Internet Engineering Task Force (IETF) S. Lhomme
Request for Comments: 9559
Updates: 8794 M. Bunkus
Category: Standards Track
ISSN: 2070-1721 D. Rice
October 2024
Matroska Media Container Format Specification
Abstract
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This document defines the Matroska audiovisual data container structure, including definitions of its structural elements, terminology, vocabulary, and application.
This document updates RFC 8794 to permit the use of a previously reserved Extensible Binary Meta Language (EBML) Element ID.
Status of This Memo
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This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9559.
Copyright Notice
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Copyright © 2024 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.
Table of Contents
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1. Introduction 2. Status of This Document 3. Notation and Conventions 4. Matroska Overview 4.1. Principles 4.2. Updates to RFC 8794 4.3. Added EBML Constraints 4.4. Design Rules 4.5. Data Layout 5. Matroska Schema 5.1. Segment Element 5.1.1. SeekHead Element 5.1.1.1. Seek Element 5.1.2. Info Element 5.1.2.1. SegmentUUID Element 5.1.2.2. SegmentFilename Element 5.1.2.3. PrevUUID Element 5.1.2.4. PrevFilename Element 5.1.2.5. NextUUID Element 5.1.2.6. NextFilename Element 5.1.2.7. SegmentFamily Element 5.1.2.8. ChapterTranslate Element 5.1.2.9. TimestampScale Element 5.1.2.10. Duration Element 5.1.2.11. DateUTC Element 5.1.2.12. Title Element 5.1.2.13. MuxingApp Element 5.1.2.14. WritingApp Element 5.1.3. Cluster Element 5.1.3.1. Timestamp Element 5.1.3.2. Position Element 5.1.3.3. PrevSize Element 5.1.3.4. SimpleBlock Element 5.1.3.5. BlockGroup Element 5.1.4. Tracks Element 5.1.4.1. TrackEntry Element 5.1.5. Cues Element 5.1.5.1. CuePoint Element 5.1.6. Attachments Element 5.1.6.1. AttachedFile Element 5.1.7. Chapters Element 5.1.7.1. EditionEntry Element 5.1.8. Tags Element 5.1.8.1. Tag Element 6. Matroska Element Ordering 6.1. Top-Level Elements 6.2. CRC-32 6.3. SeekHead 6.4. Cues (Index) 6.5. Info 6.6. Chapters Element 6.7. Attachments 6.8. Tags 7. Matroska Versioning 8. Stream Copy 9. DefaultDecodedFieldDuration 10. Cluster Blocks 10.1. Block Structure 10.2. SimpleBlock Structure 10.3. Block Lacing 10.3.1. No Lacing 10.3.2. Xiph Lacing 10.3.3. EBML Lacing 10.3.4. Fixed-size Lacing 10.3.5. Laced Frames Timestamp 10.4. Random Access Points 11. Timestamps 11.1. Timestamp Ticks 11.1.1. Matroska Ticks 11.1.2. Segment Ticks 11.1.3. Track Ticks 11.2. Block Timestamps 11.3. TimestampScale Rounding 12. Language Codes 13. Country Codes 14. Encryption 15. Image Presentation 15.1. Cropping 15.2. Rotation 16. Segment Position 16.1. Segment Position Exception 16.2. Example of Segment Position 17. Linked Segments 17.1. Hard Linking 17.2. Medium Linking 17.2.1. Linked-Duration 17.2.2. Linked-Edition 18. Track Flags 18.1. Default Flag 18.2. Forced Flag 18.3. Hearing-Impaired Flag 18.4. Visual-Impaired Flag 18.5. Descriptions Flag 18.6. Original Flag 18.7. Commentary Flag 18.8. Track Operation 18.9. Overlay Track 18.10. Multi-planar and 3D Videos 19. Default Track Selection 19.1. Audio Selection 19.2. Subtitle Selection 20. Chapters 20.1. EditionEntry 20.1.1. EditionFlagDefault 20.1.2. Default Edition 20.1.3. EditionFlagOrdered 20.1.3.1. Ordered-Edition and Matroska Segment Linking 20.2. ChapterAtom 20.2.1. ChapterTimeStart 20.2.2. ChapterTimeEnd 20.2.3. Nested Chapters 20.2.4. Nested Chapters in Ordered Chapters 20.2.5. ChapterFlagHidden 20.3. Menu Features 20.4. Physical Types 20.5. Chapter Examples 20.5.1. Example 1: Basic Chaptering 20.5.2. Example 2: Nested Chapters 20.5.2.1. The Micronauts "Bleep To Bleep" 21. Attachments 21.1. Cover Art 21.2. Font Files 22. Cues 22.1. Recommendations 23. Matroska Streaming 23.1. File Access 23.2. Livestreaming 24. Tags 24.1. Tags Precedence 24.2. Tag Levels 25. Implementation Recommendations 25.1. Cluster 25.2. SeekHead 25.3. Optimum Layouts 25.3.1. Optimum Layout for a Muxer 25.3.2. Optimum Layout after Editing Tags 25.3.3. Optimum Layout with Cues at the Front 25.3.4. Optimum Layout for Livestreaming 26. Security Considerations 27. IANA Considerations 27.1. Matroska Element IDs Registry 27.2. Matroska Compression Algorithms Registry 27.3. Matroska Encryption Algorithms Registry 27.4. Matroska AES Cipher Modes Registry 27.5. Matroska Content Encoding Scopes Registry 27.6. Matroska Content Encoding Types Registry 27.7. Matroska Stereo Modes Registry 27.8. Matroska Alpha Modes Registry 27.9. Matroska Display Units Registry 27.10. Matroska Horizontal Chroma Sitings Registry 27.11. Matroska Vertical Chroma Sitings Registry 27.12. Matroska Color Ranges Registry 27.13. Matroska Tags Target Types Registry 27.14. Matroska Chapter Codec IDs Registry 27.15. Matroska Projection Types Registry 27.16. Matroska Track Types Registry 27.17. Matroska Track Plane Types Registry 27.18. Media Types 27.18.1. For Files Containing Video Tracks 27.18.2. For Files Containing Audio Tracks with No Video Tracks 27.18.3. For Files Containing a Stereoscopic Video Track 28. References 28.1. Normative References 28.2. Informative References Appendix A. Historic Deprecated Elements A.1. SilentTracks Element A.2. SilentTrackNumber Element A.3. BlockVirtual Element A.4. ReferenceVirtual Element A.5. Slices Element A.6. TimeSlice Element A.7. LaceNumber Element A.8. FrameNumber Element A.9. BlockAdditionID Element A.10. Delay Element A.11. SliceDuration Element A.12. ReferenceFrame Element A.13. ReferenceOffset Element A.14. ReferenceTimestamp Element A.15. EncryptedBlock Element A.16. MinCache Element A.17. MaxCache Element A.18. TrackOffset Element A.19. CodecSettings Element A.20. CodecInfoURL Element A.21. CodecDownloadURL Element A.22. CodecDecodeAll Element A.23. TrackOverlay Element A.24. AspectRatioType Element A.25. GammaValue Element A.26. FrameRate Element A.27. ChannelPositions Element A.28. TrickTrackUID Element A.29. TrickTrackSegmentUID Element A.30. TrickTrackFlag Element A.31. TrickMasterTrackUID Element A.32. TrickMasterTrackSegmentUID Element A.33. ContentSignature Element A.34. ContentSigKeyID Element A.35. ContentSigAlgo Element A.36. ContentSigHashAlgo Element A.37. CueRefCluster Element A.38. CueRefNumber Element A.39. CueRefCodecState Element A.40. FileReferral Element A.41. FileUsedStartTime Element A.42. FileUsedEndTime Element A.43. TagDefaultBogus Element Authors' Addresses
1. Introduction
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Matroska is an audiovisual data container format. It was derived from a project called [MCF] but diverges from it significantly because it is based on EBML (Extensible Binary Meta Language) [RFC8794], a binary derivative of XML. EBML provides significant advantages in terms of future format extensibility, without breaking file support in parsers reading the previous versions.
To avoid any misunderstandings, it is essential to clarify exactly what an audio/video container is:
- It is NOT a video or audio compression format (codec).
- It is an envelope in which there can be many audio, video, and subtitles streams, allowing the user to store a complete movie or CD in a single file.
Matroska is designed with the future in mind. It incorporates features such as:
- Fast seeking in the file
- Chapter entries
* Full metadata (tags) support
- Selectable subtitle/audio/video streams
- Modularly expandable
- Error resilience (can recover playback even when the stream is damaged)
- Streamable over the Internet and local networks (HTTP [RFC9110], FTP [RFC0959], SMB [SMB-CIFS], etc.)
* Menus (like menus that DVDs have [DVD-Video])
2. Status of This Document
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This document covers Matroska versions 1, 2, 3, and 4. Matroska version 4 is the current version. Matroska versions 1 to 3 are no longer maintained. No new elements are expected in files with version numbers 1, 2, or 3.
3. Notation and Conventions
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This document defines the following terms in order to define the format and application of Matroska:
Matroska: A multimedia container format based on EBML (Extensible Binary Meta Language). Matroska Reader: A data parser that interprets the semantics of a Matroska document and creates a way for programs to use Matroska. Matroska Player: A Matroska Reader with the primary purpose of playing audiovisual files, including Matroska documents. Matroska Writer: A data writer that creates Matroska documents.
4. Matroska Overview
4.1. Principles
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Matroska is a Document Type of EBML. This specification is dependent on the EBML specification [RFC8794]. For an understanding of Matroska's EBML Schema, see in particular the sections of the EBML specification that cover EBML Element Types (Section 7), EBML Schema (Section 11.1), and EBML Structure (Section 3).
4.2. Updates to RFC 8794
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Because of an oversight, [RFC8794] reserved EBML ID 0x80, which is used by deployed Matroska implementations. For this reason, this specification updates [RFC8794] to make 0x80 a legal EBML ID. Additionally, this specification makes the following updates:
* Section 17.1 of [RFC8794] (per Erratum ID #7189 [Err7189])
OLD:
| One-octet Element IDs MUST be between 0x81 and 0xFE. These items | are valuable because they are short, and they need to be used for | commonly repeated elements. Element IDs are to be allocated | within this range according to the "RFC Required" policy | [RFC8126]. | | The following one-octet Element IDs are RESERVED: 0xFF and 0x80.
NEW:
| One-octet Element IDs MUST be between 0x80 and 0xFE. These items | are valuable because they are short, and they need to be used for | commonly repeated elements. Element IDs are to be allocated | within this range according to the "RFC Required" policy | [RFC8126]. | | The following one-octet Element ID is RESERVED: 0xFF. * Section 5 of [RFC8794] (per Erratum ID #7191 [Err7191])
OLD:
+=========================+================+=================+ | Element ID Octet Length | Range of Valid | Number of Valid | | | Element IDs | Element IDs | +=========================+================+=================+ | 1 | 0x81 - 0xFE | 126 | +-------------------------+----------------+-----------------+NEW:
+=========================+================+=================+ | Element ID Octet Length | Range of Valid | Number of Valid | | | Element IDs | Element IDs | +=========================+================+=================+ | 1 | 0x80 - 0xFE | 127 | +-------------------------+----------------+-----------------+
4.3. Added EBML Constraints
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As an EBML Document Type, Matroska adds the following constraints to the EBML specification [RFC8794]:
- The docType of the EBML Header MUST be "matroska".
- The EBMLMaxIDLength of the EBML Header MUST be 4.
- The EBMLMaxSizeLength of the EBML Header MUST be between 1 and 8, inclusive.
4.4. Design Rules
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The Root Element and all Top-Level Elements MUST use 4 octets for their EBML Element ID -- i.e., Segment and direct children of Segment.
Legacy EBML/Matroska parsers did not handle Empty Elements properly; elements were present in the file but had a length of 0. They always assumed the value was 0 for integers/dates or 0x0p+0, the textual expression of floats using the format in [ISO9899], no matter the default value of the element that should have been used instead. Therefore, Matroska Writers MUST NOT use EBML Empty Elements if the element has a default value that is not 0 for integers/dates and 0x0p+0 for floats.
When adding new elements to Matroska, these rules apply:
- A non-mandatory integer/date Element MUST NOT have a default value other than 0.
- A non-mandatory float Element MUST NOT have a default value other than 0x0p+0.
- A non-mandatory string Element MUST NOT have a default value, as empty strings cannot be defined in the XML Schema.
4.5. Data Layout
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A Matroska file MUST be composed of at least one EBML Document using the Matroska Document Type. Each EBML Document MUST start with an EBML Header and MUST be followed by the EBML Root Element, defined as Segment in Matroska. Matroska defines several Top-Level Elements that may occur within the Segment.
As an example, a simple Matroska file consisting of a single EBML Document could be represented like this:
* EBML Header * Segment
A more complex Matroska file consisting of an EBML Stream (consisting of two EBML Documents) could be represented like this:
* EBML Header
* Segment
* EBML Header
* SegmentThe following diagram represents a simple Matroska file, comprised of an EBML Document with an EBML Header, a Segment element (the Root Element), and all eight Matroska Top-Level Elements. In the diagrams in this section, horizontal spacing expresses a parent-child relationship between Matroska elements (e.g., the Info element is contained within the Segment element), whereas vertical alignment represents the storage order within the file.
+-------------+ | EBML Header | +---------------------------+ | Segment | SeekHead | | |-------------| | | Info | | |-------------| | | Tracks | | |-------------| | | Chapters | | |-------------| | | Cluster | | |-------------| | | Cues | | |-------------| | | Attachments | | |-------------| | | Tags | +---------------------------+
Figure 1: Basic Layout of a Matroska File
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The Matroska EBML Schema defines eight Top-Level Elements:
- SeekHead (Section 6.3)
- Info (Section 6.5)
- Tracks (Section 18)
- Chapters (Section 20)
- Cluster (Section 10)
- Cues (Section 22)
- Attachments (Section 21)
- Tags (Section 6.8)
The SeekHead element (also known as MetaSeek) contains an index of Top-Level Elements locations within the Segment. Use of the SeekHead element is RECOMMENDED. Without a SeekHead element, a Matroska parser would have to search the entire file to find all of the other Top-Level Elements. This is due to Matroska's flexible ordering requirements; for instance, it is acceptable for the Chapters element to be stored after the Cluster element(s).
+--------------------------------+ | SeekHead | Seek | SeekID | | | |--------------| | | | SeekPosition | +--------------------------------+
Figure 2: Representation of a SeekHead Element
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The Info element contains vital information for identifying the whole Segment. This includes the title for the Segment, a randomly generated unique identifier (UID), and the UID(s) of any linked Segment elements.
+-------------------------+ | Info | SegmentUUID | | |------------------| | | SegmentFilename | | |------------------| | | PrevUUID | | |------------------| | | PrevFilename | | |------------------| | | NextUUID | | |------------------| | | NextFilename | | |------------------| | | SegmentFamily | | |------------------| | | ChapterTranslate | | |------------------| | | TimestampScale | | |------------------| | | Duration | | |------------------| | | DateUTC | | |------------------| | | Title | | |------------------| | | MuxingApp | | |------------------| | | WritingApp | |-------------------------|
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Figure 3: Representation of an Info Element and Its Child Elements
The Tracks element defines the technical details for each track and can store the name, number, UID, language, and type (audio, video, subtitles, etc.) of each track. For example, the Tracks element MAY store information about the resolution of a video track or sample rate of an audio track.
The Tracks element MUST identify all the data needed by the codec to decode the data of the specified track. However, the data required is contingent on the codec used for the track. For example, a Track element for uncompressed audio only requires the audio bit rate to be present. A codec such as AC-3 would require that the CodecID element be present for all tracks, as it is the primary way to identify which codec to use to decode the track.
+------------------------------------+ | Tracks | TrackEntry | TrackNumber | | | |--------------| | | | TrackUID | | | |--------------| | | | TrackType | | | |--------------| | | | Name | | | |--------------| | | | Language | | | |--------------| | | | CodecID | | | |--------------| | | | CodecPrivate | | | |--------------| | | | CodecName | | | |----------------------------------+ | | | Video | FlagInterlaced | | | | |-------------------| | | | | FieldOrder | | | | |-------------------| | | | | StereoMode | | | | |-------------------| | | | | AlphaMode | | | | |-------------------| | | | | PixelWidth | | | | |-------------------| | | | | PixelHeight | | | | |-------------------| | | | | DisplayWidth | | | | |-------------------| | | | | DisplayHeight | | | | |-------------------| | | | | AspectRatioType | | | | |-------------------| | | | | Colour | | | |----------------------------------| | | | Audio | SamplingFrequency | | | | |-------------------| | | | | Channels | | | | |-------------------| | | | | BitDepth | |--------------------------------------------------------|
Figure 4: Representation of the Tracks Element and a Selection of Its
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Descendant Elements
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The Chapters element lists all of the chapters. Chapters are a way to set predefined points to jump to in video or audio.
+-----------------------------------------+ | Chapters | Edition | EditionUID | | | Entry |--------------------| | | | EditionFlagDefault | | | |--------------------| | | | EditionFlagOrdered | | | |---------------------------------+ | | | ChapterAtom | ChapterUID | | | | |-------------------| | | | | ChapterStringUID | | | | |-------------------| | | | | ChapterTimeStart | | | | |-------------------| | | | | ChapterTimeEnd | | | | |-------------------| | | | | ChapterFlagHidden | | | | |-------------------------------+ | | | | ChapterDisplay | ChapString | | | | | |--------------| | | | | | ChapLanguage | +------------------------------------------------------------------+
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Figure 5: Representation of the Chapters Element and a Selection
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of Its Descendant Elements
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Cluster elements contain the content for each track, e.g., video frames. A Matroska file SHOULD contain at least one Cluster element. In the rare case it doesn't, there should be a method for Segments to link together, possibly using Chapters; see Section 17.
The Cluster element helps to break up SimpleBlock or BlockGroup elements and helps with seeking and error protection. Every Cluster element MUST contain a Timestamp element. This SHOULD be the Timestamp element used to play the first Block in the Cluster element, unless a different value is needed to accommodate for more Blocks; see Section 11.2.
Cluster elements contain one or more Block element, such as BlockGroup or SimpleBlock elements. In some situations, a Cluster element MAY contain no Block element, for example, in a live recording when no data has been collected.
A BlockGroup element MAY contain a Block of data and any information relating directly to that Block.
+--------------------------+ | Cluster | Timestamp | | |----------------| | | Position | | |----------------| | | PrevSize | | |----------------| | | SimpleBlock | | |----------------| | | BlockGroup | +--------------------------+
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Figure 6: Representation of a Cluster Element and Its Immediate
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Child Elements
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+----------------------------------+ | Block | Portion of | Data Type | | | a Block | - Bit Flag | | |--------------------------+ | | Header | TrackNumber | | | |-------------| | | | Timestamp | | | |-------------| | | | Flags | | | | - Gap | | | | - Lacing | | | | - Reserved | | |--------------------------| | | Optional | FrameSize | | |--------------------------| | | Data | Frame | +----------------------------------+
Figure 7: Representation of the Block Element Structure
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Each Cluster MUST contain exactly one Timestamp element. The Timestamp element value MUST be stored once per Cluster. The Timestamp element in the Cluster is relative to the entire Segment. The Timestamp element SHOULD be the first element in the Cluster it belongs to or the second element if that Cluster contains a CRC-32 element (Section 6.2).
Additionally, the Block contains an offset that, when added to the Cluster's Timestamp element value, yields the Block's effective timestamp. Therefore, the timestamp in the Block itself is relative to the Timestamp element in the Cluster. For example, if the Timestamp element in the Cluster is set to 10 seconds and a Block in that Cluster is supposed to be played 12 seconds into the clip, the timestamp in the Block would be set to 2 seconds.
The ReferenceBlock in the BlockGroup is used instead of the basic "P-frame"/"B-frame" description. Instead of simply saying that this Block depends on the Block directly before or directly after, the Timestamp of the necessary Block is used. Because there can be as many ReferenceBlock elements as necessary for a Block, it allows for some extremely complex referencing.
The Cues element is used to seek when playing back a file by providing a temporal index for some of the Tracks. It is similar to the SeekHead element but is used for seeking to a specific time when playing back the file. It is possible to seek without this element, but it is much more difficult because a Matroska Reader would have to "hunt and peck" through the file to look for the correct timestamp.
The Cues element SHOULD contain at least one CuePoint element. Each CuePoint element stores the position of the Cluster that contains the BlockGroup or SimpleBlock element. The timestamp is stored in the CueTime element, and the location is stored in the CueTrackPositions element.
The Cues element is flexible. For instance, the Cues element can be used to index every single timestamp of every Block or they can be indexed selectively.
+-------------------------------------+ | Cues | CuePoint | CueTime | | | |-------------------| | | | CueTrackPositions | | |------------------------------| | | CuePoint | CueTime | | | |-------------------| | | | CueTrackPositions | +-------------------------------------+
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Figure 8: Representation of a Cues Element and Two Levels of Its
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Descendant Elements
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The Attachments element is for attaching files to a Matroska file, such as pictures, fonts, web pages, etc.
+------------------------------------------------+ | Attachments | AttachedFile | FileDescription | | | |-------------------| | | | FileName | | | |-------------------| | | | FileMediaType | | | |-------------------| | | | FileData | | | |-------------------| | | | FileUID | +------------------------------------------------+
Figure 9: Representation of an Attachments Element
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The Tags element contains metadata that describes the Segment and potentially its Tracks, Chapters, and Attachments. Each Track or Chapter that those tags applies to has its UID listed in the Tags. The Tags contain all extra information about the file: scriptwriters, singers, actors, directors, titles, edition, price, dates, genre, comments, etc. Tags can contain their values in multiple languages. For example, a movie's "TITLE" tag value might contain both the original English title as well as the German title.
+-------------------------------------------+ | Tags | Tag | Targets | TargetTypeValue | | | | |------------------| | | | | TargetType | | | | |------------------| | | | | TagTrackUID | | | | |------------------| | | | | TagEditionUID | | | | |------------------| | | | | TagChapterUID | | | | |------------------| | | | | TagAttachmentUID | | | |------------------------------| | | | SimpleTag | TagName | | | | |------------------| | | | | TagLanguage | | | | |------------------| | | | | TagDefault | | | | |------------------| | | | | TagString | | | | |------------------| | | | | TagBinary | | | | |------------------| | | | | SimpleTag | +-------------------------------------------+
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Figure 10: Representation of a Tags Element and Three Levels of
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Its Children Elements
5. Matroska Schema
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This specification includes an EBML Schema that defines the elements and structure of Matroska using the EBML Schema elements and attributes defined in Section 11.1 of [RFC8794].
Attributes using their default value (like minOccurs, minver, etc.) or attributes with undefined values (like length, maxver, etc.) are omitted.
The definitions for each Matroska element are provided below.
5.1. Segment Element
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id / type: 0x18538067 / master unknownsizeallowed: True path: \Segment minOccurs / maxOccurs: 1 / 1 definition: The Root Element that contains all other Top-Level Elements; see Section 4.5.
5.1.1. SeekHead Element
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id / type: 0x114D9B74 / master path: \Segment\SeekHead maxOccurs: 2 definition: Contains seeking information of Top-Level Elements; see Section 4.5.
5.1.1.1. Seek Element
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id / type: 0x4DBB / master path: \Segment\SeekHead\Seek minOccurs: 1 definition: Contains a single seek entry to an EBML Element.
5.1.1.1.1. SeekID Element
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id / type: 0x53AB / binary length: 4 path: \Segment\SeekHead\Seek\SeekID minOccurs / maxOccurs: 1 / 1 definition: The binary EBML ID of a Top-Level Element.
5.1.1.1.2. SeekPosition Element
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id / type: 0x53AC / uinteger path: \Segment\SeekHead\Seek\SeekPosition minOccurs / maxOccurs: 1 / 1 definition: The Segment Position (Section 16) of a Top-Level Element.
5.1.2. Info Element
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id / type: 0x1549A966 / master path: \Segment\Info minOccurs / maxOccurs: 1 / 1 recurring: True definition: Contains general information about the Segment.
5.1.2.1. SegmentUUID Element
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id / type: 0x73A4 / binary length: 16 path: \Segment\Info\SegmentUUID maxOccurs: 1 definition: A randomly generated UID that identifies the Segment amongst many others (128 bits). It is equivalent to a Universally Unique Identifier (UUID) v4 [RFC9562] with all bits randomly (or pseudorandomly) chosen. An actual UUID v4 value, where some bits are not random, MAY also be used. usage notes: If the Segment is a part of a Linked Segment, then this element is REQUIRED. The value of the UID MUST contain at least one bit set to 1.
5.1.2.2. SegmentFilename Element
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id / type: 0x7384 / utf-8 path: \Segment\Info\SegmentFilename maxOccurs: 1 definition: A filename corresponding to this Segment.
5.1.2.3. PrevUUID Element
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id / type: 0x3CB923 / binary length: 16 path: \Segment\Info\PrevUUID maxOccurs: 1 definition: An ID that identifies the previous Segment of a Linked Segment. usage notes: If the Segment is a part of a Linked Segment that uses Hard Linking (Section 17.1), then either the PrevUUID or the NextUUID element is REQUIRED. If a Segment contains a PrevUUID but not a NextUUID, then it MAY be considered as the last Segment of the Linked Segment. The PrevUUID MUST NOT be equal to the SegmentUUID.
5.1.2.4. PrevFilename Element
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id / type: 0x3C83AB / utf-8 path: \Segment\Info\PrevFilename maxOccurs: 1 definition: A filename corresponding to the file of the previous Linked Segment. usage notes: Provision of the previous filename is for display convenience, but PrevUUID SHOULD be considered authoritative for identifying the previous Segment in a Linked Segment.
5.1.2.5. NextUUID Element
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id / type: 0x3EB923 / binary length: 16 path: \Segment\Info\NextUUID maxOccurs: 1 definition: An ID that identifies the next Segment of a Linked Segment. usage notes: If the Segment is a part of a Linked Segment that uses Hard Linking (Section 17.1), then either the PrevUUID or the NextUUID element is REQUIRED. If a Segment contains a NextUUID but not a PrevUUID, then it MAY be considered as the first Segment of the Linked Segment. The NextUUID MUST NOT be equal to the SegmentUUID.
5.1.2.6. NextFilename Element
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id / type: 0x3E83BB / utf-8 path: \Segment\Info\NextFilename maxOccurs: 1 definition: A filename corresponding to the file of the next Linked Segment. usage notes: Provision of the next filename is for display convenience, but NextUUID SHOULD be considered authoritative for identifying the Next Segment.
5.1.2.7. SegmentFamily Element
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id / type: 0x4444 / binary length: 16 path: \Segment\Info\SegmentFamily definition: A UID that all Segments of a Linked Segment MUST share (128 bits). It is equivalent to a UUID v4 [RFC9562] with all bits randomly (or pseudorandomly) chosen. An actual UUID v4 value, where some bits are not random, MAY also be used. usage notes: If the Segment Info contains a ChapterTranslate element, this element is REQUIRED.
5.1.2.8. ChapterTranslate Element
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id / type: 0x6924 / master path: \Segment\Info\ChapterTranslate definition: The mapping between this Segment and a segment value in the given Chapter Codec. rationale: Chapter Codecs may need to address different segments, but they may not know of the way to identify such segments when stored in Matroska. This element and its child elements add a way to map the internal segments known to the Chapter Codec to the SegmentUUIDs in Matroska. This allows remuxing a file with Chapter Codec without changing the content of the codec data, just the Segment mapping.
5.1.2.8.1. ChapterTranslateID Element
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id / type: 0x69A5 / binary path: \Segment\Info\ChapterTranslate\ChapterTranslateID minOccurs / maxOccurs: 1 / 1 definition: The binary value used to represent this Segment in the chapter codec data. The format depends on the ChapProcessCodecID used; see Section 5.1.7.1.4.15.
5.1.2.8.2. ChapterTranslateCodec Element
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id / type: 0x69BF / uinteger path: \Segment\Info\ChapterTranslate\ChapterTranslateCodec minOccurs / maxOccurs: 1 / 1 definition: Applies to the chapter codec of the given chapter edition(s); see Section 5.1.7.1.4.15. defined values: See Table 31. Additional values can be registered in the "Matroska Chapter Codec IDs" registry defined in Section 27.14.
5.1.2.8.3. ChapterTranslateEditionUID Element
-
id / type: 0x69FC / uinteger path: \Segment\Info\ChapterTranslate\ChapterTranslateEditionUID definition: Specifies a chapter edition UID to which this ChapterTranslate applies. usage notes: When no ChapterTranslateEditionUID is specified in the ChapterTranslate, the ChapterTranslate applies to all chapter editions found in the Segment using the given ChapterTranslateCodec.
5.1.2.9. TimestampScale Element
-
id / type / default: 0x2AD7B1 / uinteger / 1000000 range: not 0 (1-18446744073709551615) path: \Segment\Info\TimestampScale minOccurs / maxOccurs: 1 / 1 definition: Base unit for Segment Ticks and Track Ticks, in nanoseconds. A TimestampScale value of 1000000 means scaled timestamps in the Segment are expressed in milliseconds; see Section 11 on how to interpret timestamps.
5.1.2.10. Duration Element
-
id / type: 0x4489 / float range: > 0x0p+0 path: \Segment\Info\Duration maxOccurs: 1 definition: Duration of the Segment, expressed in Segment Ticks, which are based on TimestampScale; see Section 11.1.
5.1.2.11. DateUTC Element
-
id / type: 0x4461 / date path: \Segment\Info\DateUTC maxOccurs: 1 definition: The date and time that the Segment was created by the muxing application or library.
5.1.2.12. Title Element
-
id / type: 0x7BA9 / utf-8 path: \Segment\Info\Title maxOccurs: 1 definition: General name of the Segment.
5.1.2.13. MuxingApp Element
-
id / type: 0x4D80 / utf-8 path: \Segment\Info\MuxingApp minOccurs / maxOccurs: 1 / 1 definition: Muxing application or library (example: "libmatroska- 0.4.3"). usage notes: Include the full name of the application or library followed by the version number.
5.1.2.14. WritingApp Element
-
id / type: 0x5741 / utf-8 path: \Segment\Info\WritingApp minOccurs / maxOccurs: 1 / 1 definition: Writing application (example: "mkvmerge-0.3.3"). usage notes: Include the full name of the application followed by the version number.
5.1.3. Cluster Element
-
id / type: 0x1F43B675 / master unknownsizeallowed: True path: \Segment\Cluster definition: The Top-Level Element containing the (monolithic) Block structure.
5.1.3.1. Timestamp Element
-
id / type: 0xE7 / uinteger path: \Segment\Cluster\Timestamp minOccurs / maxOccurs: 1 / 1 definition: Absolute timestamp of the cluster, expressed in Segment Ticks, which are based on TimestampScale; see Section 11.1. usage notes: This element SHOULD be the first child element of the Cluster it belongs to or the second if that Cluster contains a CRC-32 element (Section 6.2).
5.1.3.2. Position Element
-
id / type: 0xA7 / uinteger path: \Segment\Cluster\Position maxOccurs: 1 maxver: 4 definition: The Segment Position of the Cluster in the Segment (0 in live streams). It might help to resynchronize the offset on damaged streams.
5.1.3.3. PrevSize Element
-
id / type: 0xAB / uinteger path: \Segment\Cluster\PrevSize maxOccurs: 1 definition: Size of the previous Cluster, in octets. Can be useful for backward playing.
5.1.3.4. SimpleBlock Element
-
id / type: 0xA3 / binary path: \Segment\Cluster\SimpleBlock minver: 2 definition: Similar to Block (see Section 10.1) but without all the extra information. Mostly used to reduce overhead when no extra feature is needed; see Section 10.2 on SimpleBlock Structure.
5.1.3.5. BlockGroup Element
-
id / type: 0xA0 / master path: \Segment\Cluster\BlockGroup definition: Basic container of information containing a single Block and information specific to that Block.
5.1.3.5.1. Block Element
-
id / type: 0xA1 / binary path: \Segment\Cluster\BlockGroup\Block minOccurs / maxOccurs: 1 / 1 definition: Block containing the actual data to be rendered and a timestamp relative to the Cluster Timestamp; see Section 10.1 on Block Structure.
5.1.3.5.2. BlockAdditions Element
-
id / type: 0x75A1 / master path: \Segment\Cluster\BlockGroup\BlockAdditions maxOccurs: 1 definition: Contains additional binary data to complete the Block element; see Section 4.1.5 of [MatroskaCodec] for more information. An EBML parser that has no knowledge of the Block structure could still see and use/skip these data.
-
id / type: 0xA6 / master path: \Segment\Cluster\BlockGroup\BlockAdditions\BlockMore minOccurs: 1 definition: Contains the BlockAdditional and some parameters.
-
id / type: 0xA5 / binary path: \Segment\Cluster\BlockGroup\BlockAdditions\BlockMore\BlockAddi tional minOccurs / maxOccurs: 1 / 1 definition: Interpreted by the codec as it wishes (using the BlockAddID).
-
id / type / default: 0xEE / uinteger / 1 range: not 0 (1-18446744073709551615) path: \Segment\Cluster\BlockGroup\BlockAdditions\BlockMore\BlockAddI D minOccurs / maxOccurs: 1 / 1 definition: An ID that identifies how to interpret the BlockAdditional data; see Section 4.1.5 of [MatroskaCodec] for more information. A value of 1 indicates that the BlockAdditional data is defined by the codec. Any other value indicates that the BlockAdditional data should be handled according to the BlockAddIDType that is located in the TrackEntry. usage notes: Each BlockAddID value MUST be unique between all BlockMore elements found in a BlockAdditions element. To keep MaxBlockAdditionID as low as possible, small values SHOULD be used.
5.1.3.5.3. BlockDuration Element
-
id / type: 0x9B / uinteger path: \Segment\Cluster\BlockGroup\BlockDuration minOccurs / maxOccurs: See Table 1 / 1 definition: The duration of the Block, expressed in Track Ticks; see Section 11.1. The BlockDuration element can be useful at the end of a Track to define the duration of the last frame (as there is no subsequent Block available) or when there is a break in a track like for subtitle tracks. notes: See Table 1. +===========+==================================================+ | attribute | note | +===========+==================================================+ | minOccurs | BlockDuration MUST be set (minOccurs=1) if the | | | associated TrackEntry stores a DefaultDuration | | | value. | +-----------+--------------------------------------------------+ | default | If a value is not present and no DefaultDuration | | | is defined, the value is assumed to be the | | | difference between the timestamp of this Block | | | and the timestamp of the next Block in "display" | | | order (not coding order). | +-----------+--------------------------------------------------+
Table 1: BlockDuration Implementation Notes
5.1.3.5.4. ReferencePriority Element
-
id / type / default: 0xFA / uinteger / 0 path: \Segment\Cluster\BlockGroup\ReferencePriority minOccurs / maxOccurs: 1 / 1 definition: This frame is referenced and has the specified cache priority. In the cache, only a frame of the same or higher priority can replace this frame. A value of 0 means the frame is not referenced.
5.1.3.5.5. ReferenceBlock Element
-
id / type: 0xFB / integer path: \Segment\Cluster\BlockGroup\ReferenceBlock definition: A timestamp value, relative to the timestamp of the Block in this BlockGroup, expressed in Track Ticks; see Section 11.1. This is used to reference other frames necessary to decode this frame. The relative value SHOULD correspond to a valid Block that this Block depends on. Historically, Matroska Writers didn't write the actual Block(s) that this Block depends on, but they did write _some_ Block(s) in the past.The value "0" MAY also be used to signify that this Block cannot be decoded on its own, but the necessary reference Block(s) is unknown. In this case, other ReferenceBlock elements MUST NOT be found in the same BlockGroup. If the BlockGroup doesn't have a ReferenceBlock element, then the Block it contains can be decoded without using any other Block data.
5.1.3.5.6. CodecState Element
-
id / type: 0xA4 / binary path: \Segment\Cluster\BlockGroup\CodecState maxOccurs: 1 minver: 2 definition: The new codec state to use. Data interpretation is private to the codec. This information SHOULD always be referenced by a seek entry.
5.1.3.5.7. DiscardPadding Element
-
id / type: 0x75A2 / integer path: \Segment\Cluster\BlockGroup\DiscardPadding maxOccurs: 1 minver: 4 definition: Duration of the silent data added to the Block, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1 (padding at the end of the Block for positive values and at the beginning of the Block for negative values). The duration of DiscardPadding is not calculated in the duration of the TrackEntry and SHOULD be discarded during playback.
5.1.4. Tracks Element
-
id / type: 0x1654AE6B / master path: \Segment\Tracks maxOccurs: 1 recurring: True definition: A Top-Level Element of information with many tracks described.
5.1.4.1. TrackEntry Element
-
id / type: 0xAE / master path: \Segment\Tracks\TrackEntry minOccurs: 1 definition: Describes a track with all elements.
5.1.4.1.1. TrackNumber Element
-
id / type: 0xD7 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\TrackNumber minOccurs / maxOccurs: 1 / 1 definition: The track number as used in the Block Header.
5.1.4.1.2. TrackUID Element
-
id / type: 0x73C5 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\TrackUID minOccurs / maxOccurs: 1 / 1 definition: A UID that identifies the Track. stream copy: True (Section 8)
5.1.4.1.3. TrackType Element
-
id / type: 0x83 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\TrackType minOccurs / maxOccurs: 1 / 1 definition: The TrackType defines the type of each frame found in the Track. The value SHOULD be stored on 1 octet. defined values: See Table 2. Additional values can be registered in the "Matroska Track Types" registry defined in Section 27.16. stream copy: True (Section 8) +=======+==========+==========================================+ | value | label | contents of each frame | +=======+==========+==========================================+ | 1 | video | An image. | +-------+----------+------------------------------------------+ | 2 | audio | Audio samples. | +-------+----------+------------------------------------------+ | 3 | complex | A mix of different other TrackType. The | | | | codec needs to define how the Matroska | | | | Player should interpret such data. | +-------+----------+------------------------------------------+ | 16 | logo | An image to be rendered over the video | | | | track(s). | +-------+----------+------------------------------------------+ | 17 | subtitle | Subtitle or closed caption data to be | | | | rendered over the video track(s). | +-------+----------+------------------------------------------+ | 18 | buttons | Interactive button(s) to be rendered | | | | over the video track(s). | +-------+----------+------------------------------------------+ | 32 | control | Metadata used to control the player of | | | | the Matroska Player. | +-------+----------+------------------------------------------+ | 33 | metadata | Timed metadata that can be passed on to | | | | the Matroska Player. | +-------+----------+------------------------------------------+
Table 2: TrackType Values
5.1.4.1.4. FlagEnabled Element
-
id / type / default: 0xB9 / uinteger / 1 range: 0-1 path: \Segment\Tracks\TrackEntry\FlagEnabled minOccurs / maxOccurs: 1 / 1 minver: 2 definition: Set to 1 if the track is usable. It is possible to turn a track that is not usable into a usable track using chapter codecs or control tracks.
5.1.4.1.5. FlagDefault Element
-
id / type / default: 0x88 / uinteger / 1 range: 0-1 path: \Segment\Tracks\TrackEntry\FlagDefault minOccurs / maxOccurs: 1 / 1 definition: Set to 1 if the track (audio, video, or subtitles) is eligible for automatic selection by the player; see Section 19 for more details.
5.1.4.1.6. FlagForced Element
-
id / type / default: 0x55AA / uinteger / 0 range: 0-1 path: \Segment\Tracks\TrackEntry\FlagForced minOccurs / maxOccurs: 1 / 1 definition: Applies only to subtitles. Set to 1 if the track is eligible for automatic selection by the player if it matches the user's language preference, even if the user's preferences would not normally enable subtitles with the selected audio track; this can be used for tracks containing only translations of audio in foreign languages or on-screen text. See Section 19 for more details.
5.1.4.1.7. FlagHearingImpaired Element
-
id / type: 0x55AB / uinteger range: 0-1 path: \Segment\Tracks\TrackEntry\FlagHearingImpaired maxOccurs: 1 minver: 4 definition: Set to 1 if and only if the track is suitable for users with hearing impairments.
5.1.4.1.8. FlagVisualImpaired Element
-
id / type: 0x55AC / uinteger range: 0-1 path: \Segment\Tracks\TrackEntry\FlagVisualImpaired maxOccurs: 1 minver: 4 definition: Set to 1 if and only if the track is suitable for users with visual impairments.
5.1.4.1.9. FlagTextDescriptions Element
-
id / type: 0x55AD / uinteger range: 0-1 path: \Segment\Tracks\TrackEntry\FlagTextDescriptions maxOccurs: 1 minver: 4 definition: Set to 1 if and only if the track contains textual descriptions of video content.
5.1.4.1.10. FlagOriginal Element
-
id / type: 0x55AE / uinteger range: 0-1 path: \Segment\Tracks\TrackEntry\FlagOriginal maxOccurs: 1 minver: 4 definition: Set to 1 if and only if the track is in the content's original language.
5.1.4.1.11. FlagCommentary Element
-
id / type: 0x55AF / uinteger range: 0-1 path: \Segment\Tracks\TrackEntry\FlagCommentary maxOccurs: 1 minver: 4 definition: Set to 1 if and only if the track contains commentary.
5.1.4.1.12. FlagLacing Element
-
id / type / default: 0x9C / uinteger / 1 range: 0-1 path: \Segment\Tracks\TrackEntry\FlagLacing minOccurs / maxOccurs: 1 / 1 definition: Set to 1 if the track MAY contain blocks that use lacing. When set to 0, all blocks MUST have their lacing flags set to "no lacing"; see Section 10.3 on 'Block' Lacing.
5.1.4.1.13. DefaultDuration Element
-
id / type: 0x23E383 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\DefaultDuration maxOccurs: 1 definition: Number of nanoseconds per frame, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1 ("frame" in the Matroska sense -- one element put into a (Simple)Block). stream copy: True (Section 8)
5.1.4.1.14. DefaultDecodedFieldDuration Element
-
id / type: 0x234E7A / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\DefaultDecodedFieldDuration maxOccurs: 1 minver: 4 definition: The period between two successive fields at the output of the decoding process, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1. See Section 9 for more information. stream copy: True (Section 8)
5.1.4.1.15. TrackTimestampScale Element
-
id / type / default: 0x23314F / float / 0x1p+0 range: > 0x0p+0 path: \Segment\Tracks\TrackEntry\TrackTimestampScale minOccurs / maxOccurs: 1 / 1 maxver: 3 definition: The scale to apply on this track to work at normal speed in relation with other tracks (mostly used to adjust video speed when the audio length differs). stream copy: True (Section 8)
5.1.4.1.16. MaxBlockAdditionID Element
-
id / type / default: 0x55EE / uinteger / 0 path: \Segment\Tracks\TrackEntry\MaxBlockAdditionID minOccurs / maxOccurs: 1 / 1 definition: The maximum value of BlockAddID (Section 5.1.3.5.2.3). A value of 0 means there is no BlockAdditions (Section 5.1.3.5.2) for this track.
5.1.4.1.17. BlockAdditionMapping Element
-
id / type: 0x41E4 / master path: \Segment\Tracks\TrackEntry\BlockAdditionMapping minver: 4 definition: Contains elements that extend the track format by adding content either to each frame, with BlockAddID (Section 5.1.3.5.2.3), or to the track as a whole with BlockAddIDExtraData.
-
id / type: 0x41F0 / uinteger range: >=2 path: \Segment\Tracks\TrackEntry\BlockAdditionMapping\BlockAddIDValu e maxOccurs: 1 minver: 4 definition: If the track format extension needs content beside frames, the value refers to the BlockAddID (Section 5.1.3.5.2.3) value being described. usage notes: To keep MaxBlockAdditionID as low as possible, small values SHOULD be used.
-
id / type: 0x41A4 / string path: \Segment\Tracks\TrackEntry\BlockAdditionMapping\BlockAddIDName maxOccurs: 1 minver: 4 definition: A human-friendly name describing the type of BlockAdditional data, as defined by the associated Block Additional Mapping.
-
id / type / default: 0x41E7 / uinteger / 0 path: \Segment\Tracks\TrackEntry\BlockAdditionMapping\BlockAddIDType minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Stores the registered identifier of the Block Additional Mapping to define how the BlockAdditional data should be handled. usage notes: If BlockAddIDType is 0, the BlockAddIDValue and corresponding BlockAddID values MUST be 1.
-
id / type: 0x41ED / binary path: \Segment\Tracks\TrackEntry\BlockAdditionMapping\BlockAddIDExtr aData maxOccurs: 1 minver: 4 definition: Extra binary data that the BlockAddIDType can use to interpret the BlockAdditional data. The interpretation of the binary data depends on the BlockAddIDType value and the corresponding Block Additional Mapping.
5.1.4.1.18. Name Element
-
id / type: 0x536E / utf-8 path: \Segment\Tracks\TrackEntry\Name maxOccurs: 1 definition: A human-readable track name.
5.1.4.1.19. Language Element
-
id / type / default: 0x22B59C / string / eng path: \Segment\Tracks\TrackEntry\Language minOccurs / maxOccurs: 1 / 1 definition: The language of the track, in the Matroska languages form; see Section 12 on language codes. This element MUST be ignored if the LanguageBCP47 element is used in the same TrackEntry.
5.1.4.1.20. LanguageBCP47 Element
-
id / type: 0x22B59D / string path: \Segment\Tracks\TrackEntry\LanguageBCP47 maxOccurs: 1 minver: 4 definition: The language of the track, in the form defined in [RFC5646]; see Section 12 on language codes. If this element is used, then any Language elements used in the same TrackEntry MUST be ignored.
5.1.4.1.21. CodecID Element
-
id / type: 0x86 / string path: \Segment\Tracks\TrackEntry\CodecID minOccurs / maxOccurs: 1 / 1 definition: An ID corresponding to the codec; see [MatroskaCodec] for more info. stream copy: True (Section 8)
5.1.4.1.22. CodecPrivate Element
-
id / type: 0x63A2 / binary path: \Segment\Tracks\TrackEntry\CodecPrivate maxOccurs: 1 definition: Private data only known to the codec. stream copy: True (Section 8)
5.1.4.1.23. CodecName Element
-
id / type: 0x258688 / utf-8 path: \Segment\Tracks\TrackEntry\CodecName maxOccurs: 1 definition: A human-readable string specifying the codec.
5.1.4.1.24. AttachmentLink Element
-
id / type: 0x7446 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\AttachmentLink maxOccurs: 1 maxver: 3 definition: The UID of an attachment that is used by this codec. usage notes: The value MUST match the FileUID value of an attachment found in this Segment.
5.1.4.1.25. CodecDelay Element
-
id / type / default: 0x56AA / uinteger / 0 path: \Segment\Tracks\TrackEntry\CodecDelay minOccurs / maxOccurs: 1 / 1 minver: 4 definition: The built-in delay for the codec, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1. It represents the number of codec samples that will be discarded by the decoder during playback. This timestamp value MUST be subtracted from each frame timestamp in order to get the timestamp that will be actually played. The value SHOULD be small so the muxing of tracks with the same actual timestamp are in the same Cluster. stream copy: True (Section 8)
5.1.4.1.26. SeekPreRoll Element
-
id / type / default: 0x56BB / uinteger / 0 path: \Segment\Tracks\TrackEntry\SeekPreRoll minOccurs / maxOccurs: 1 / 1 minver: 4 definition: After a discontinuity, the duration of the data that the decoder MUST decode before the decoded data is valid, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1. stream copy: True (Section 8)
5.1.4.1.27. TrackTranslate Element
-
id / type: 0x6624 / master path: \Segment\Tracks\TrackEntry\TrackTranslate definition: The mapping between this TrackEntry and a track value in the given Chapter Codec. rationale: Chapter Codecs may need to address content in a specific track, but they may not know of the way to identify tracks in Matroska. This element and its child elements add a way to map the internal tracks known to the Chapter Codec to the track IDs in Matroska. This allows remuxing a file with Chapter Codec without changing the content of the codec data, just the track mapping.
-
id / type: 0x66A5 / binary path: \Segment\Tracks\TrackEntry\TrackTranslate\TrackTranslateTrackI D minOccurs / maxOccurs: 1 / 1 definition: The binary value used to represent this TrackEntry in the chapter codec data. The format depends on the ChapProcessCodecID used; see Section 5.1.7.1.4.15.
-
id / type: 0x66BF / uinteger path: \Segment\Tracks\TrackEntry\TrackTranslate\TrackTranslateCodec minOccurs / maxOccurs: 1 / 1 definition: Applies to the chapter codec of the given chapter edition(s); see Section 5.1.7.1.4.15. defined values: See Table 31. Additional values can be registered in the "Matroska Chapter Codec IDs" registry defined in Section 27.14.
-
id / type: 0x66FC / uinteger path: \Segment\Tracks\TrackEntry\TrackTranslate\TrackTranslateEditio nUID definition: Specifies a chapter edition UID to which this TrackTranslate applies. usage notes: When no TrackTranslateEditionUID is specified in the TrackTranslate, the TrackTranslate applies to all chapter editions found in the Segment using the given TrackTranslateCodec.
5.1.4.1.28. Video Element
-
id / type: 0xE0 / master path: \Segment\Tracks\TrackEntry\Video maxOccurs: 1 definition: Video settings.
-
id / type / default: 0x9A / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\FlagInterlaced minOccurs / maxOccurs: 1 / 1 minver: 2 definition: Specifies whether the video frames in this track are interlaced. restrictions: See Table 3. stream copy: True (Section 8) +=======+==============+==========================+ | value | label | definition | +=======+==============+==========================+ | 0 | undetermined | Unknown status. This | | | | value SHOULD be avoided. | +-------+--------------+--------------------------+ | 1 | interlaced | Interlaced frames. | +-------+--------------+--------------------------+ | 2 | progressive | No interlacing. | +-------+--------------+--------------------------+
Table 3: FlagInterlaced Values
-
id / type / default: 0x9D / uinteger / 2 path: \Segment\Tracks\TrackEntry\Video\FieldOrder minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Specifies the field ordering of video frames in this track. restrictions: See Table 4. usage notes: If FlagInterlaced is not set to 1, this element MUST be ignored. stream copy: True (Section 8) +=======+===============+=========================================+ | value | label | definition | +=======+===============+=========================================+ | 0 | progressive | Interlaced frames. This value SHOULD | | | | be avoided; setting FlagInterlaced to 2 | | | | is sufficient. | +-------+---------------+-----------------------------------------+ | 1 | tff | Top field displayed first. Top field | | | | stored first. | +-------+---------------+-----------------------------------------+ | 2 | undetermined | Unknown field order. This value SHOULD | | | | be avoided. | +-------+---------------+-----------------------------------------+ | 6 | bff | Bottom field displayed first. Bottom | | | | field stored first. | +-------+---------------+-----------------------------------------+ | 9 | tff | Top field displayed first. Fields are | | | (interleaved) | interleaved in storage with the top | | | | line of the top field stored first. | +-------+---------------+-----------------------------------------+ | 14 | bff | Bottom field displayed first. Fields | | | (interleaved) | are interleaved in storage with the top | | | | line of the top field stored first. | +-------+---------------+-----------------------------------------+
Table 4: FieldOrder Values
-
id / type / default: 0x53B8 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\StereoMode minOccurs / maxOccurs: 1 / 1 minver: 3 definition: Stereo-3D video mode. See Section 18.10 for more details. defined values: See Table 5. Additional values can be registered in the "Matroska Stereo Modes" registry defined in Section 27.7. stream copy: True (Section 8) +=======+===================================================+ | value | label | +=======+===================================================+ | 0 | mono | +-------+---------------------------------------------------+ | 1 | side by side (left eye first) | +-------+---------------------------------------------------+ | 2 | top - bottom (right eye is first) | +-------+---------------------------------------------------+ | 3 | top - bottom (left eye is first) | +-------+---------------------------------------------------+ | 4 | checkboard (right eye is first) | +-------+---------------------------------------------------+ | 5 | checkboard (left eye is first) | +-------+---------------------------------------------------+ | 6 | row interleaved (right eye is first) | +-------+---------------------------------------------------+ | 7 | row interleaved (left eye is first) | +-------+---------------------------------------------------+ | 8 | column interleaved (right eye is first) | +-------+---------------------------------------------------+ | 9 | column interleaved (left eye is first) | +-------+---------------------------------------------------+ | 10 | anaglyph (cyan/red) | +-------+---------------------------------------------------+ | 11 | side by side (right eye first) | +-------+---------------------------------------------------+ | 12 | anaglyph (green/magenta) | +-------+---------------------------------------------------+ | 13 | both eyes laced in one Block (left eye is first) | +-------+---------------------------------------------------+ | 14 | both eyes laced in one Block (right eye is first) | +-------+---------------------------------------------------+
Table 5: StereoMode Values
-
id / type / default: 0x53C0 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\AlphaMode minOccurs / maxOccurs: 1 / 1 minver: 3 definition: Indicates whether the BlockAdditional element with BlockAddID of "1" contains Alpha data as defined by the Codec Mapping for the CodecID. Undefined values (i.e., values other than 0 or 1) SHOULD NOT be used, as the behavior of known implementations is different. defined values: See Table 6. Additional values can be registered in the "Matroska Alpha Modes" registry defined in Section 27.8. stream copy: True (Section 8) +=======+=========+============================================+ | value | label | definition | +=======+=========+============================================+ | 0 | none | The BlockAdditional element with | | | | BlockAddID of "1" does not exist or SHOULD | | | | NOT be considered as containing such data. | +-------+---------+--------------------------------------------+ | 1 | present | The BlockAdditional element with | | | | BlockAddID of "1" contains alpha channel | | | | data. | +-------+---------+--------------------------------------------+
Table 6: AlphaMode Values
-
id / type: 0x53B9 / uinteger path: \Segment\Tracks\TrackEntry\Video\OldStereoMode maxOccurs: 1 maxver: 2 definition: Bogus StereoMode value used in old versions of [libmatroska]. restrictions: See Table 7. usage notes: This element MUST NOT be used. It was an incorrect value used in libmatroska up to 0.9.0. +=======+===========+ | value | label | +=======+===========+ | 0 | mono | +-------+-----------+ | 1 | right eye | +-------+-----------+ | 2 | left eye | +-------+-----------+ | 3 | both eyes | +-------+-----------+
Table 7: OldStereoMode
Values
-
id / type: 0xB0 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Video\PixelWidth minOccurs / maxOccurs: 1 / 1 definition: Width of the encoded video frames in pixels. stream copy: True (Section 8)
-
id / type: 0xBA / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Video\PixelHeight minOccurs / maxOccurs: 1 / 1 definition: Height of the encoded video frames in pixels. stream copy: True (Section 8)
-
id / type / default: 0x54AA / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\PixelCropBottom minOccurs / maxOccurs: 1 / 1 definition: The number of video pixels to remove at the bottom of the image. stream copy: True (Section 8)
-
id / type / default: 0x54BB / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\PixelCropTop minOccurs / maxOccurs: 1 / 1 definition: The number of video pixels to remove at the top of the image. stream copy: True (Section 8)
-
id / type / default: 0x54CC / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\PixelCropLeft minOccurs / maxOccurs: 1 / 1 definition: The number of video pixels to remove on the left of the image. stream copy: True (Section 8)
-
id / type / default: 0x54DD / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\PixelCropRight minOccurs / maxOccurs: 1 / 1 definition: The number of video pixels to remove on the right of the image. stream copy: True (Section 8)
-
id / type: 0x54B0 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Video\DisplayWidth maxOccurs: 1 definition: Width of the video frames to display. Applies to the video frame after cropping (PixelCrop* Elements). notes: See Table 8. stream copy: True (Section 8) +===========+==================================================+ | attribute | note | +===========+==================================================+ | default | If the DisplayUnit of the same TrackEntry is 0, | | | then the default value for DisplayWidth is equal | | | to PixelWidth - PixelCropLeft - PixelCropRight; | | | else, there is no default value. | +-----------+--------------------------------------------------+
Table 8: DisplayWidth Implementation Notes
-
id / type: 0x54BA / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Video\DisplayHeight maxOccurs: 1 definition: Height of the video frames to display. Applies to the video frame after cropping (PixelCrop* Elements). notes: See Table 9. stream copy: True (Section 8) +===========+===================================================+ | attribute | note | +===========+===================================================+ | default | If the DisplayUnit of the same TrackEntry is 0, | | | then the default value for DisplayHeight is equal | | | to PixelHeight - PixelCropTop - PixelCropBottom; | | | else, there is no default value. | +-----------+---------------------------------------------------+
Table 9: DisplayHeight Implementation Notes
-
id / type / default: 0x54B2 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\DisplayUnit minOccurs / maxOccurs: 1 / 1 definition: How DisplayWidth and DisplayHeight are interpreted. defined values: See Table 10. Additional values can be registered in the "Matroska Display Units" registry defined in Section 27.9. +=======+======================+ | value | label | +=======+======================+ | 0 | pixels | +-------+----------------------+ | 1 | centimeters | +-------+----------------------+ | 2 | inches | +-------+----------------------+ | 3 | display aspect ratio | +-------+----------------------+ | 4 | unknown | +-------+----------------------+
Table 10: DisplayUnit Values
-
id / type: 0x2EB524 / binary length: 4 path: \Segment\Tracks\TrackEntry\Video\UncompressedFourCC minOccurs / maxOccurs: See Table 11 / 1 definition: Specifies the uncompressed pixel format used for the Track's data as a FourCC. This value is similar in scope to the biCompression value of AVI's BITMAPINFO [AVIFormat]. There is neither a definitive list of FourCC values nor an official registry. Some common values for YUV pixel formats can be found at [MSYUV8], [MSYUV16], and [FourCC-YUV]. Some common values for uncompressed RGB pixel formats can be found at [MSRGB] and [FourCC-RGB]. notes: See Table 11. stream copy: True (Section 8) +===========+==============================================+ | attribute | note | +===========+==============================================+ | minOccurs | UncompressedFourCC MUST be set (minOccurs=1) | | | in TrackEntry when the CodecID element of | | | the TrackEntry is set to "V_UNCOMPRESSED". | +-----------+----------------------------------------------+
Table 11: UncompressedFourCC Implementation Notes
-
id / type: 0x55B0 / master path: \Segment\Tracks\TrackEntry\Video\Colour maxOccurs: 1 minver: 4 definition: Settings describing the color format. stream copy: True (Section 8)
-
id / type / default: 0x55B1 / uinteger / 2 path: \Segment\Tracks\TrackEntry\Video\Colour\MatrixCoefficients minOccurs / maxOccurs: 1 / 1 minver: 4 definition: The Matrix Coefficients of the video used to derive luma and chroma values from red, green, and blue color primaries. For clarity, the value and meanings for MatrixCoefficients are adopted from Table 4 of [ITU-H.273]. restrictions: See Table 12. stream copy: True (Section 8) +=======+=======================================+ | value | label | +=======+=======================================+ | 0 | Identity | +-------+---------------------------------------+ | 1 | ITU-R BT.709 | +-------+---------------------------------------+ | 2 | unspecified | +-------+---------------------------------------+ | 3 | reserved | +-------+---------------------------------------+ | 4 | US FCC 73.682 | +-------+---------------------------------------+ | 5 | ITU-R BT.470BG | +-------+---------------------------------------+ | 6 | SMPTE 170M | +-------+---------------------------------------+ | 7 | SMPTE 240M | +-------+---------------------------------------+ | 8 | YCoCg | +-------+---------------------------------------+ | 9 | BT2020 Non-constant Luminance | +-------+---------------------------------------+ | 10 | BT2020 Constant Luminance | +-------+---------------------------------------+ | 11 | SMPTE ST 2085 | +-------+---------------------------------------+ | 12 | Chroma-derived Non-constant Luminance | +-------+---------------------------------------+ | 13 | Chroma-derived Constant Luminance | +-------+---------------------------------------+ | 14 | ITU-R BT.2100-0 | +-------+---------------------------------------+
Table 12: MatrixCoefficients Values
-
id / type / default: 0x55B2 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\Colour\BitsPerChannel minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Number of decoded bits per channel. A value of 0 indicates that the BitsPerChannel is unspecified. stream copy: True (Section 8)
-
id / type: 0x55B3 / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\ChromaSubsamplingHorz maxOccurs: 1 minver: 4 definition: The number of pixels to remove in the Cr and Cb channels for every pixel not removed horizontally. Example: For video with 4:2:0 chroma subsampling, the ChromaSubsamplingHorz SHOULD be set to 1. stream copy: True (Section 8)
-
id / type: 0x55B4 / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\ChromaSubsamplingVert maxOccurs: 1 minver: 4 definition: The number of pixels to remove in the Cr and Cb channels for every pixel not removed vertically. Example: For video with 4:2:0 chroma subsampling, the ChromaSubsamplingVert SHOULD be set to 1. stream copy: True (Section 8)
-
id / type: 0x55B5 / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\CbSubsamplingHorz maxOccurs: 1 minver: 4 definition: The number of pixels to remove in the Cb channel for every pixel not removed horizontally. This is additive with ChromaSubsamplingHorz. Example: For video with 4:2:1 chroma subsampling, the ChromaSubsamplingHorz SHOULD be set to 1, and CbSubsamplingHorz SHOULD be set to 1. stream copy: True (Section 8)
-
id / type: 0x55B6 / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\CbSubsamplingVert maxOccurs: 1 minver: 4 definition: The number of pixels to remove in the Cb channel for every pixel not removed vertically. This is additive with ChromaSubsamplingVert. stream copy: True (Section 8)
-
id / type / default: 0x55B7 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\Colour\ChromaSitingHorz minOccurs / maxOccurs: 1 / 1 minver: 4 definition: How chroma is subsampled horizontally. defined values: See Table 13. Additional values can be registered in the "Matroska Horizontal Chroma Sitings" registry defined in Section 27.10. stream copy: True (Section 8) +=======+=================+ | value | label | +=======+=================+ | 0 | unspecified | +-------+-----------------+ | 1 | left collocated | +-------+-----------------+ | 2 | half | +-------+-----------------+
Table 13:
ChromaSitingHorz Values
-
id / type / default: 0x55B8 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\Colour\ChromaSitingVert minOccurs / maxOccurs: 1 / 1 minver: 4 definition: How chroma is subsampled vertically. defined values: See Table 14. Additional values can be registered in the "Matroska Vertical Chroma Sitings" registry defined in Section 27.11. stream copy: True (Section 8) +=======+================+ | value | label | +=======+================+ | 0 | unspecified | +-------+----------------+ | 1 | top collocated | +-------+----------------+ | 2 | half | +-------+----------------+
Table 14:
ChromaSitingVert
Values
-
id / type / default: 0x55B9 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\Colour\Range minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Clipping of the color ranges. defined values: See Table 15. Additional values can be registered in the "Matroska Color Ranges" registry defined in Section 27.12. stream copy: True (Section 8) +=======+=========================================================+ | value | label | +=======+=========================================================+ | 0 | unspecified | +-------+---------------------------------------------------------+ | 1 | broadcast range | +-------+---------------------------------------------------------+ | 2 | full range (no clipping) | +-------+---------------------------------------------------------+ | 3 | defined by MatrixCoefficients / TransferCharacteristics | +-------+---------------------------------------------------------+
Table 15: Range Values
-
id / type / default: 0x55BA / uinteger / 2 path: \Segment\Tracks\TrackEntry\Video\Colour\TransferCharacteristic s minOccurs / maxOccurs: 1 / 1 minver: 4 definition: The transfer characteristics of the video. For clarity, the value and meanings for TransferCharacteristics are adopted from Table 3 of [ITU-H.273]. restrictions: See Table 16. stream copy: True (Section 8) +=======+=======================================+ | value | label | +=======+=======================================+ | 0 | reserved | +-------+---------------------------------------+ | 1 | ITU-R BT.709 | +-------+---------------------------------------+ | 2 | unspecified | +-------+---------------------------------------+ | 3 | reserved2 | +-------+---------------------------------------+ | 4 | Gamma 2.2 curve - BT.470M | +-------+---------------------------------------+ | 5 | Gamma 2.8 curve - BT.470BG | +-------+---------------------------------------+ | 6 | SMPTE 170M | +-------+---------------------------------------+ | 7 | SMPTE 240M | +-------+---------------------------------------+ | 8 | Linear | +-------+---------------------------------------+ | 9 | Log | +-------+---------------------------------------+ | 10 | Log Sqrt | +-------+---------------------------------------+ | 11 | IEC 61966-2-4 | +-------+---------------------------------------+ | 12 | ITU-R BT.1361 Extended Colour Gamut | +-------+---------------------------------------+ | 13 | IEC 61966-2-1 | +-------+---------------------------------------+ | 14 | ITU-R BT.2020 10 bit | +-------+---------------------------------------+ | 15 | ITU-R BT.2020 12 bit | +-------+---------------------------------------+ | 16 | ITU-R BT.2100 Perceptual Quantization | +-------+---------------------------------------+ | 17 | SMPTE ST 428-1 | +-------+---------------------------------------+ | 18 | ARIB STD-B67 (HLG) | +-------+---------------------------------------+
Table 16: TransferCharacteristics Values
-
id / type / default: 0x55BB / uinteger / 2 path: \Segment\Tracks\TrackEntry\Video\Colour\Primaries minOccurs / maxOccurs: 1 / 1 minver: 4 definition: The color primaries of the video. For clarity, the value and meanings for Primaries are adopted from Table 2 of [ITU-H.273]. restrictions: See Table 17. stream copy: True (Section 8) +=======+========================================+ | value | label | +=======+========================================+ | 0 | reserved | +-------+----------------------------------------+ | 1 | ITU-R BT.709 | +-------+----------------------------------------+ | 2 | unspecified | +-------+----------------------------------------+ | 3 | reserved2 | +-------+----------------------------------------+ | 4 | ITU-R BT.470M | +-------+----------------------------------------+ | 5 | ITU-R BT.470BG - BT.601 625 | +-------+----------------------------------------+ | 6 | ITU-R BT.601 525 - SMPTE 170M | +-------+----------------------------------------+ | 7 | SMPTE 240M | +-------+----------------------------------------+ | 8 | FILM | +-------+----------------------------------------+ | 9 | ITU-R BT.2020 | +-------+----------------------------------------+ | 10 | SMPTE ST 428-1 | +-------+----------------------------------------+ | 11 | SMPTE RP 432-2 | +-------+----------------------------------------+ | 12 | SMPTE EG 432-2 | +-------+----------------------------------------+ | 22 | EBU Tech. 3213-E - JEDEC P22 phosphors | +-------+----------------------------------------+
Table 17: Primaries Values
-
id / type: 0x55BC / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\MaxCLL maxOccurs: 1 minver: 4 definition: Maximum brightness of a single pixel (Maximum Content Light Level) in candelas per square meter (cd/m^2). stream copy: True (Section 8)
-
id / type: 0x55BD / uinteger path: \Segment\Tracks\TrackEntry\Video\Colour\MaxFALL maxOccurs: 1 minver: 4 definition: Maximum brightness of a single full frame (Maximum Frame-Average Light Level) in candelas per square meter (cd/m^2). stream copy: True (Section 8)
-
id / type: 0x55D0 / master path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata maxOccurs: 1 minver: 4 definition: SMPTE 2086 mastering data. stream copy: True (Section 8)
-
id / type: 0x55D1 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryRChromaticityX maxOccurs: 1 minver: 4 definition: Red X chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D2 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryRChromaticityY maxOccurs: 1 minver: 4 definition: Red Y chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D3 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryGChromaticityX maxOccurs: 1 minver: 4 definition: Green X chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D4 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryGChromaticityY maxOccurs: 1 minver: 4 definition: Green Y chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D5 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryBChromaticityX maxOccurs: 1 minver: 4 definition: Blue X chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D6 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Prim aryBChromaticityY maxOccurs: 1 minver: 4 definition: Blue Y chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D7 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Whit ePointChromaticityX maxOccurs: 1 minver: 4 definition: White X chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D8 / float range: 0x0p+0-0x1p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Whit ePointChromaticityY maxOccurs: 1 minver: 4 definition: White Y chromaticity coordinate, as defined by [CIE-1931]. stream copy: True (Section 8)
-
id / type: 0x55D9 / float range: >= 0x0p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Lumi nanceMax maxOccurs: 1 minver: 4 definition: Maximum luminance. Represented in candelas per square meter (cd/m^2). stream copy: True (Section 8)
-
id / type: 0x55DA / float range: >= 0x0p+0 path: \Segment\Tracks\TrackEntry\Video\Colour\MasteringMetadata\Lumi nanceMin maxOccurs: 1 minver: 4 definition: Minimum luminance. Represented in candelas per square meter (cd/m^2). stream copy: True (Section 8)
-
id / type: 0x7670 / master path: \Segment\Tracks\TrackEntry\Video\Projection maxOccurs: 1 minver: 4 definition: Describes the video projection details. Used to render spherical or VR videos or to flip videos horizontally or vertically. stream copy: True (Section 8)
-
id / type / default: 0x7671 / uinteger / 0 path: \Segment\Tracks\TrackEntry\Video\Projection\ProjectionType minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Describes the projection used for this video track. defined values: See Table 18. Additional values can be registered in the "Matroska Projection Types" registry defined in Section 27.15. stream copy: True (Section 8) +=======+=================+ | value | label | +=======+=================+ | 0 | rectangular | +-------+-----------------+ | 1 | equirectangular | +-------+-----------------+ | 2 | cubemap | +-------+-----------------+ | 3 | mesh | +-------+-----------------+
Table 18:
ProjectionType Values
-
id / type: 0x7672 / binary path: \Segment\Tracks\TrackEntry\Video\Projection\ProjectionPrivate maxOccurs: 1 minver: 4 definition: Private data that only applies to a specific projection. * If ProjectionType equals 0 (rectangular), then this element MUST NOT be present. * If ProjectionType equals 1 (equirectangular), then this element MUST be present and contain the same binary data that would be stored inside an ISOBMFF Equirectangular Projection Box ("equi"). * If ProjectionType equals 2 (cubemap), then this element MUST be present and contain the same binary data that would be stored inside an ISOBMFF Cubemap Projection Box ("cbmp"). * If ProjectionType equals 3 (mesh), then this element MUST be present and contain the same binary data that would be stored inside an ISOBMFF Mesh Projection Box ("mshp"). usage notes: ISOBMFF box size and FourCC fields are not included in the binary data, but the FullBox version and flag fields are. This is to avoid redundant framing information while preserving versioning and semantics between the two container formats. stream copy: True (Section 8)
-
id / type / default: 0x7673 / float / 0x0p+0 range: >= -0xB4p+0, <= 0xB4p+0 path: \Segment\Tracks\TrackEntry\Video\Projection\ProjectionPoseYaw minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Specifies a yaw rotation to the projection. Value represents a clockwise rotation, in degrees, around the up vector. This rotation must be applied before any ProjectionPosePitch or ProjectionPoseRoll rotations. The value of this element MUST be in the -180 to 180 degree range, both inclusive.Setting ProjectionPoseYaw to 180 or -180 degrees with ProjectionPoseRoll and ProjectionPosePitch set to 0 degrees flips the image horizontally.
stream copy: True (Section 8)
-
id / type / default: 0x7674 / float / 0x0p+0 range: >= -0x5Ap+0, <= 0x5Ap+0 path: \Segment\Tracks\TrackEntry\Video\Projection\ProjectionPosePitc h minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Specifies a pitch rotation to the projection. Value represents a counter-clockwise rotation, in degrees, around the right vector. This rotation must be applied after the ProjectionPoseYaw rotation and before the ProjectionPoseRoll rotation. The value of this element MUST be in the -90 to 90 degree range, both inclusive. stream copy: True (Section 8)
-
id / type / default: 0x7675 / float / 0x0p+0 range: >= -0xB4p+0, <= 0xB4p+0 path: \Segment\Tracks\TrackEntry\Video\Projection\ProjectionPoseRoll minOccurs / maxOccurs: 1 / 1 minver: 4 definition: Specifies a roll rotation to the projection. Value represents a counter-clockwise rotation, in degrees, around the forward vector. This rotation must be applied after the ProjectionPoseYaw and ProjectionPosePitch rotations. The value of this element MUST be in the -180 to 180 degree range, both inclusive. Setting ProjectionPoseRoll to 180 or -180 degrees and ProjectionPoseYaw to 180 or -180 degrees with ProjectionPosePitch set to 0 degrees flips the image vertically. Setting ProjectionPoseRoll to 180 or -180 degrees with ProjectionPoseYaw and ProjectionPosePitch set to 0 degrees flips the image horizontally and vertically. stream copy: True (Section 8)
5.1.4.1.29. Audio Element
-
id / type: 0xE1 / master path: \Segment\Tracks\TrackEntry\Audio maxOccurs: 1 definition: Audio settings.
-
id / type / default: 0xB5 / float / 0x1.f4p+12 range: > 0x0p+0 path: \Segment\Tracks\TrackEntry\Audio\SamplingFrequency minOccurs / maxOccurs: 1 / 1 definition: Sampling frequency in Hz. stream copy: True (Section 8)
-
id / type: 0x78B5 / float range: > 0x0p+0 path: \Segment\Tracks\TrackEntry\Audio\OutputSamplingFrequency maxOccurs: 1 definition: Real output sampling frequency in Hz that is used for Spectral Band Replication (SBR) techniques. notes: See Table 19. +===========+======================================================+ | attribute | note | +===========+======================================================+ | default | The default value for OutputSamplingFrequency of the | | | same TrackEntry is equal to the SamplingFrequency. | +-----------+------------------------------------------------------+
Table 19: OutputSamplingFrequency Implementation Notes
-
id / type / default: 0x9F / uinteger / 1 range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Audio\Channels minOccurs / maxOccurs: 1 / 1 definition: Numbers of channels in the track. stream copy: True (Section 8)
-
id / type: 0x6264 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\Audio\BitDepth maxOccurs: 1 definition: Bits per sample, mostly used for PCM. stream copy: True (Section 8)
5.1.4.1.30. TrackOperation Element
-
id / type: 0xE2 / master path: \Segment\Tracks\TrackEntry\TrackOperation maxOccurs: 1 minver: 3 definition: Operation that needs to be applied on tracks to create this virtual track. For more details, see Section 18.8. stream copy: True (Section 8)
-
id / type: 0xE3 / master path: \Segment\Tracks\TrackEntry\TrackOperation\TrackCombinePlanes maxOccurs: 1 minver: 3 definition: Contains the list of all video plane tracks that need to be combined to create this 3D track. stream copy: True (Section 8)
-
id / type: 0xE4 / master path: \Segment\Tracks\TrackEntry\TrackOperation\TrackCombinePlanes\T rackPlane minOccurs: 1 minver: 3 definition: Contains a video plane track that needs to be combined to create this 3D track. stream copy: True (Section 8)
-
id / type: 0xE5 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\TrackOperation\TrackCombinePlanes\T rackPlane\TrackPlaneUID minOccurs / maxOccurs: 1 / 1 minver: 3 definition: The TrackUID number of the track representing the plane. stream copy: True (Section 8)
-
id / type: 0xE6 / uinteger path: \Segment\Tracks\TrackEntry\TrackOperation\TrackCombinePlanes\T rackPlane\TrackPlaneType minOccurs / maxOccurs: 1 / 1 minver: 3 definition: The kind of plane this track corresponds to. defined values: See Table 20. Additional values can be registered in the "Matroska Track Plane Types" registry defined in Section 27.17. stream copy: True (Section 8) +=======+============+ | value | label | +=======+============+ | 0 | left eye | +-------+------------+ | 1 | right eye | +-------+------------+ | 2 | background | +-------+------------+
Table 20:
TrackPlaneType Values
-
id / type: 0xE9 / master path: \Segment\Tracks\TrackEntry\TrackOperation\TrackJoinBlocks maxOccurs: 1 minver: 3 definition: Contains the list of all tracks whose Blocks need to be combined to create this virtual track. stream copy: True (Section 8)
-
id / type: 0xED / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\TrackOperation\TrackJoinBlocks\Trac kJoinUID minOccurs: 1 minver: 3 definition: The TrackUID number of a track whose blocks are used to create this virtual track. stream copy: True (Section 8)
5.1.4.1.31. ContentEncodings Element
-
id / type: 0x6D80 / master path: \Segment\Tracks\TrackEntry\ContentEncodings maxOccurs: 1 definition: Settings for several content encoding mechanisms like compression or encryption. stream copy: True (Section 8)
-
id / type: 0x6240 / master path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding minOccurs: 1 definition: Settings for one content encoding like compression or encryption. stream copy: True (Section 8)
-
id / type / default: 0x5031 / uinteger / 0 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncodingOrder minOccurs / maxOccurs: 1 / 1 definition: Defines the order to apply each ContentEncoding of the ContentEncodings. The decoder/demuxer MUST start with the ContentEncoding with the highest ContentEncodingOrder and work its way down to the ContentEncoding with the lowest ContentEncodingOrder. This value MUST be unique for each ContentEncoding found in the ContentEncodings of this TrackEntry. stream copy: True (Section 8)
-
id / type / default: 0x5032 / uinteger / 1 range: not 0 (0x1-0x8000000000000000) path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncodingScope minOccurs / maxOccurs: 1 / 1 definition: A bit field that describes which elements have been modified in this way. Values (big-endian) can be OR'ed. defined values: See Table 21. Additional values can be registered in the "Matroska Content Encoding Scopes" registry defined in Section 27.5. stream copy: True (Section 8) +=======+=========+============================================+ | value | label | definition | +=======+=========+============================================+ | 0x1 | Block | All frame contents, excluding lacing data. | +-------+---------+--------------------------------------------+ | 0x2 | Private | The track's CodecPrivate data. | +-------+---------+--------------------------------------------+ | 0x4 | Next | The next ContentEncoding (next | | | | ContentEncodingOrder; the data inside | | | | ContentCompression and/or | | | | ContentEncryption). This value SHOULD NOT | | | | be used, as it's not supported by players. | +-------+---------+--------------------------------------------+
Table 21: ContentEncodingScope Values
-
id / type / default: 0x5033 / uinteger / 0 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncodingType minOccurs / maxOccurs: 1 / 1 definition: A value describing the kind of transformation that is applied. defined values: See Table 22. Additional values can be registered in the "Matroska Content Encoding Types" registry defined in Section 27.6. stream copy: True (Section 8) +=======+=============+ | value | label | +=======+=============+ | 0 | Compression | +-------+-------------+ | 1 | Encryption | +-------+-------------+
Table 22:
ContentEncodingType
Values
-
id / type: 0x5034 / master path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentCompression maxOccurs: 1 definition: Settings describing the compression used. This element MUST be present if the value of ContentEncodingType is 0 and absent otherwise. Each block MUST be decompressable, even if no previous block is available in order to not prevent seeking. stream copy: True (Section 8)
-
id / type / default: 0x4254 / uinteger / 0 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentCompression\ContentCompAlgo minOccurs / maxOccurs: 1 / 1 definition: The compression algorithm used. defined values: See Table 23. Additional values can be registered in the "Matroska Compression Algorithms" registry defined in Section 27.2. usage notes: Compression method "1" (bzlib) and "2" (lzo1x) lack proper documentation on the format, which limits implementation possibilities. Due to licensing conflicts on commonly available libraries' compression methods, "2" (lzo1x) does not offer widespread interoperability. A Matroska Writer SHOULD NOT use these compression methods by default. A Matroska Reader MAY support methods "1" and "2" and SHOULD support other methods. stream copy: True (Section 8) +=======+===========+========================================+ | value | label | definition | +=======+===========+========================================+ | 0 | zlib | zlib compression [RFC1950]. | +-------+-----------+----------------------------------------+ | 1 | bzlib | bzip2 compression [BZIP2] SHOULD NOT | | | | be used; see usage notes. | +-------+-----------+----------------------------------------+ | 2 | lzo1x | Lempel-Ziv-Oberhumer compression [LZO] | | | | SHOULD NOT be used; see usage notes. | +-------+-----------+----------------------------------------+ | 3 | Header | Octets in ContentCompSettings | | | Stripping | (Section 5.1.4.1.31.7) have been | | | | stripped from each frame. | +-------+-----------+----------------------------------------+
Table 23: ContentCompAlgo Values
-
id / type: 0x4255 / binary path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentCompression\ContentCompSettings maxOccurs: 1 definition: Settings that might be needed by the decompressor. For Header Stripping (ContentCompAlgo=3), the bytes that were removed from the beginning of each frame of the track. stream copy: True (Section 8)
-
id / type: 0x5035 / master path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption maxOccurs: 1 definition: Settings describing the encryption used. This element MUST be present if the value of ContentEncodingType is 1 (encryption) and MUST be ignored otherwise. A Matroska Player MAY support encryption. stream copy: True (Section 8)
-
id / type / default: 0x47E1 / uinteger / 0 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentEncAlgo minOccurs / maxOccurs: 1 / 1 definition: The encryption algorithm used. defined values: See Table 24. Additional values can be registered in the "Matroska Encryption Algorithms" registry defined in Section 27.3. stream copy: True (Section 8) +=======+===========+============================================+ | value | label | definition | +=======+===========+============================================+ | 0 | Not | The data are not encrypted. | | | encrypted | | +-------+-----------+--------------------------------------------+ | 1 | DES | Data Encryption Standard (DES) [FIPS46-3]. | | | | This value SHOULD be avoided. | +-------+-----------+--------------------------------------------+ | 2 | 3DES | Triple Data Encryption Algorithm | | | | [SP800-67]. This value SHOULD be avoided. | +-------+-----------+--------------------------------------------+ | 3 | Twofish | Twofish Encryption Algorithm [Twofish]. | +-------+-----------+--------------------------------------------+ | 4 | Blowfish | Blowfish Encryption Algorithm [Blowfish]. | | | | This value SHOULD be avoided. | +-------+-----------+--------------------------------------------+ | 5 | AES | Advanced Encryption Standard (AES) | | | | [FIPS197]. | +-------+-----------+--------------------------------------------+
Table 24: ContentEncAlgo Values
-
id / type: 0x47E2 / binary path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentEncKeyID maxOccurs: 1 definition: For public key algorithms, the ID of the public key that the data was encrypted with. stream copy: True (Section 8)
-
id / type: 0x47E7 / master path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentEncAESSettings maxOccurs: 1 minver: 4 definition: Settings describing the encryption algorithm used. notes: See Table 25. stream copy: True (Section 8) +===========+=================================================+ | attribute | note | +===========+=================================================+ | maxOccurs | ContentEncAESSettings MUST NOT be set | | | (maxOccurs=0) if ContentEncAlgo is not AES (5). | +-----------+-------------------------------------------------+
Table 25: ContentEncAESSettings Implementation Notes
-
id / type: 0x47E8 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentEncAESSettings\AESSettingsCipherMode minOccurs / maxOccurs: 1 / 1 minver: 4 definition: The AES cipher mode used in the encryption. defined values: See Table 26. Additional values can be registered in the "Matroska AES Cipher Modes" registry defined in Section 27.4. notes: See Table 27. stream copy: True (Section 8) +=======+=========+===================================+ | value | label | definition | +=======+=========+===================================+ | 1 | AES-CTR | Counter [SP800-38A] | +-------+---------+-----------------------------------+ | 2 | AES-CBC | Cipher Block Chaining [SP800-38A] | +-------+---------+-----------------------------------+
Table 26: AESSettingsCipherMode Values
-
+===========+=================================================+ | attribute | note | +===========+=================================================+ | maxOccurs | AESSettingsCipherMode MUST NOT be set | | | (maxOccurs=0) if ContentEncAlgo is not AES (5). | +-----------+-------------------------------------------------+
Table 27: AESSettingsCipherMode Implementation Notes
5.1.5. Cues Element
-
id / type: 0x1C53BB6B / master path: \Segment\Cues minOccurs / maxOccurs: See Table 28 / 1 definition: A Top-Level Element to speed seeking access. All entries are local to the Segment. notes: See Table 28. +===========+====================================================+ | attribute | note | +===========+====================================================+ | minOccurs | This element SHOULD be set when the Segment is not | | | transmitted as a live stream; see Section 23.2. | +-----------+----------------------------------------------------+
Table 28: Cues Implementation Notes
5.1.5.1. CuePoint Element
-
id / type: 0xBB / master path: \Segment\Cues\CuePoint minOccurs: 1 definition: Contains all information relative to a seek point in the Segment.
5.1.5.1.1. CueTime Element
-
id / type: 0xB3 / uinteger path: \Segment\Cues\CuePoint\CueTime minOccurs / maxOccurs: 1 / 1 definition: Absolute timestamp of the seek point, expressed in Segment Ticks, which are based on TimestampScale; see Section 11.1.
5.1.5.1.2. CueTrackPositions Element
-
id / type: 0xB7 / master path: \Segment\Cues\CuePoint\CueTrackPositions minOccurs: 1 definition: Contains positions for different tracks corresponding to the timestamp.
-
id / type: 0xF7 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Cues\CuePoint\CueTrackPositions\CueTrack minOccurs / maxOccurs: 1 / 1 definition: The track for which a position is given.
-
id / type: 0xF1 / uinteger path: \Segment\Cues\CuePoint\CueTrackPositions\CueClusterPosition minOccurs / maxOccurs: 1 / 1 definition: The Segment Position (Section 16) of the Cluster containing the associated Block.
-
id / type: 0xF0 / uinteger path: \Segment\Cues\CuePoint\CueTrackPositions\CueRelativePosition maxOccurs: 1 minver: 4 definition: The relative position inside the Cluster of the referenced SimpleBlock or BlockGroup with 0 being the first possible position for an element inside that Cluster.
-
id / type: 0xB2 / uinteger path: \Segment\Cues\CuePoint\CueTrackPositions\CueDuration maxOccurs: 1 minver: 4 definition: The duration of the block, expressed in Segment Ticks, which are based on TimestampScale; see Section 11.1. If missing, the track's DefaultDuration does not apply and no duration information is available in terms of the cues.
-
id / type: 0x5378 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Cues\CuePoint\CueTrackPositions\CueBlockNumber maxOccurs: 1 definition: Number of the Block in the specified Cluster.
-
id / type / default: 0xEA / uinteger / 0 path: \Segment\Cues\CuePoint\CueTrackPositions\CueCodecState minOccurs / maxOccurs: 1 / 1 minver: 2 definition: The Segment Position (Section 16) of the Codec State corresponding to this Cues element. 0 means that the data is taken from the initial TrackEntry.
-
id / type: 0xDB / master path: \Segment\Cues\CuePoint\CueTrackPositions\CueReference minver: 2 definition: The Clusters containing the referenced Blocks.
-
id / type: 0x96 / uinteger path: \Segment\Cues\CuePoint\CueTrackPositions\CueReference\CueRefTi me minOccurs / maxOccurs: 1 / 1 minver: 2 definition: Timestamp of the referenced Block, expressed in Segment Ticks which is based on TimestampScale; see Section 11.1.
5.1.6. Attachments Element
-
id / type: 0x1941A469 / master path: \Segment\Attachments maxOccurs: 1 definition: Contains attached files.
5.1.6.1. AttachedFile Element
-
id / type: 0x61A7 / master path: \Segment\Attachments\AttachedFile minOccurs: 1 definition: An attached file.
5.1.6.1.1. FileDescription Element
-
id / type: 0x467E / utf-8 path: \Segment\Attachments\AttachedFile\FileDescription maxOccurs: 1 definition: A human-friendly name for the attached file.
5.1.6.1.2. FileName Element
-
id / type: 0x466E / utf-8 path: \Segment\Attachments\AttachedFile\FileName minOccurs / maxOccurs: 1 / 1 definition: Filename of the attached file.
5.1.6.1.3. FileMediaType Element
-
id / type: 0x4660 / string path: \Segment\Attachments\AttachedFile\FileMediaType minOccurs / maxOccurs: 1 / 1 definition: Media type of the file following the format described in [RFC6838]. stream copy: True (Section 8)
5.1.6.1.4. FileData Element
-
id / type: 0x465C / binary path: \Segment\Attachments\AttachedFile\FileData minOccurs / maxOccurs: 1 / 1 definition: The data of the file. stream copy: True (Section 8)
5.1.6.1.5. FileUID Element
-
id / type: 0x46AE / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Attachments\AttachedFile\FileUID minOccurs / maxOccurs: 1 / 1 definition: UID representing the file, as random as possible. stream copy: True (Section 8)
5.1.7. Chapters Element
-
id / type: 0x1043A770 / master path: \Segment\Chapters maxOccurs: 1 recurring: True definition: A system to define basic menus and partition data. For more detailed information, see Section 20.
5.1.7.1. EditionEntry Element
-
id / type: 0x45B9 / master path: \Segment\Chapters\EditionEntry minOccurs: 1 definition: Contains all information about a Segment edition.
5.1.7.1.1. EditionUID Element
-
id / type: 0x45BC / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Chapters\EditionEntry\EditionUID maxOccurs: 1 definition: A UID that identifies the edition. It's useful for tagging an edition. stream copy: True (Section 8)
5.1.7.1.2. EditionFlagDefault Element
-
id / type / default: 0x45DB / uinteger / 0 range: 0-1 path: \Segment\Chapters\EditionEntry\EditionFlagDefault minOccurs / maxOccurs: 1 / 1 definition: Set to 1 if the edition SHOULD be used as the default one.
5.1.7.1.3. EditionFlagOrdered Element
-
id / type / default: 0x45DD / uinteger / 0 range: 0-1 path: \Segment\Chapters\EditionEntry\EditionFlagOrdered minOccurs / maxOccurs: 1 / 1 definition: Set to 1 if the chapters can be defined multiple times and the order to play them is enforced; see Section 20.1.3.
5.1.7.1.4. ChapterAtom Element
-
id / type: 0xB6 / master path: \Segment\Chapters\EditionEntry\+ChapterAtom minOccurs: 1 recursive: True definition: Contains the atom information to use as the chapter atom (applies to all tracks).
-
id / type: 0x73C4 / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterUID minOccurs / maxOccurs: 1 / 1 definition: A UID that identifies the Chapter. stream copy: True (Section 8)
-
id / type: 0x5654 / utf-8 path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterStringUID maxOccurs: 1 minver: 3 definition: A unique string ID that identifies the Chapter. For example, it is used as the storage for cue identifier values [WebVTT].
-
id / type: 0x91 / uinteger path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterTimeStart minOccurs / maxOccurs: 1 / 1 definition: Timestamp of the start of Chapter, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1.
-
id / type: 0x92 / uinteger path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterTimeEnd minOccurs / maxOccurs: See Table 29 / 1 definition: Timestamp of the end of Chapter (timestamp excluded), expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1. The value MUST be greater than or equal to the ChapterTimeStart of the same ChapterAtom. usage notes: With the ChapterTimeEnd timestamp value being excluded, it MUST take into account the duration of the last frame it includes, especially for the ChapterAtom using the last frames of the Segment. notes: See Table 29. +===========+====================================================+ | attribute | note | +===========+====================================================+ | minOccurs | ChapterTimeEnd MUST be set (minOccurs=1) if the | | | Edition is an ordered edition; see Section 20.1.3. | | | If it's a Parent Chapter, see Section 20.2.3. | +-----------+----------------------------------------------------+
Table 29: ChapterTimeEnd Implementation Notes
-
id / type / default: 0x98 / uinteger / 0 range: 0-1 path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterFlagHidden minOccurs / maxOccurs: 1 / 1 definition: Set to 1 if a chapter is hidden. Hidden chapters SHOULD NOT be available to the user interface (but still be available to Control Tracks; see Section 20.2.5 on Chapter flags).
-
id / type: 0x6E67 / binary length: 16 path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterSegmentUUID minOccurs / maxOccurs: See Table 30 / 1 definition: The SegmentUUID of another Segment to play during this chapter. usage notes: The value MUST NOT be the SegmentUUID value of the Segment it belongs to. notes: See Table 30. +===========+==============================================+ | attribute | note | +===========+==============================================+ | minOccurs | ChapterSegmentUUID MUST be set (minOccurs=1) | | | if ChapterSegmentEditionUID is used; see | | | Section 17.2 on Medium-Linking Segments. | +-----------+----------------------------------------------+
Table 30: ChapterSegmentUUID Implementation Notes
-
id / type: 0x6EBC / uinteger range: not 0 (1-18446744073709551615) path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterSegmentEdit ionUID maxOccurs: 1 definition: The EditionUID to play from the Segment linked in ChapterSegmentUUID. If ChapterSegmentEditionUID is undeclared, then no Edition of the Linked Segment is used; see Section 17.2 on Medium-Linking Segments.
-
id / type: 0x63C3 / uinteger path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterPhysicalEqu iv maxOccurs: 1 definition: Specifies the physical equivalent of this ChapterAtom, e.g., "DVD" (60) or "SIDE" (50); see Section 20.4 for a complete list of values.
-
id / type: 0x80 / master path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterDisplay definition: Contains all possible strings to use for the chapter display.
-
id / type: 0x85 / utf-8 path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterDisplay\Cha pString minOccurs / maxOccurs: 1 / 1 definition: Contains the string to use as the chapter atom.
-
id / type / default: 0x437C / string / eng path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterDisplay\Cha pLanguage minOccurs: 1 definition: A language corresponding to the string, in the Matroska languages form; see Section 12 on language codes. This element MUST be ignored if a ChapLanguageBCP47 element is used within the same ChapterDisplay element.
-
id / type: 0x437D / string path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterDisplay\Cha pLanguageBCP47 minver: 4 definition: A language corresponding to the ChapString, in the form defined in [RFC5646]; see Section 12 on language codes. If a ChapLanguageBCP47 element is used, then any ChapLanguage and ChapCountry elements used in the same ChapterDisplay MUST be ignored.
-
id / type: 0x437E / string path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapterDisplay\Cha pCountry definition: A country corresponding to the string, in the Matroska countries form; see Section 13 on country codes. This element MUST be ignored if a ChapLanguageBCP47 element is used within the same ChapterDisplay element.
-
id / type: 0x6944 / master path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess definition: Contains all the commands associated with the Atom.
-
id / type / default: 0x6955 / uinteger / 0 path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess\ChapPr ocessCodecID minOccurs / maxOccurs: 1 / 1 definition: Contains the type of the codec used for processing. defined values: See Table 31. Additional values can be registered in the "Matroska Chapter Codec IDs" registry defined in Section 27.14. +=======+=================+============================+ | value | label | definition | +=======+=================+============================+ | 0 | Matroska Script | Chapter commands using the | | | | Matroska Script codec. | +-------+-----------------+----------------------------+ | 1 | DVD-menu | Chapter commands using the | | | | DVD-like codec. | +-------+-----------------+----------------------------+
Table 31: ChapProcessCodecID Values
-
id / type: 0x450D / binary path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess\ChapPr ocessPrivate maxOccurs: 1 definition: Optional data attached to the ChapProcessCodecID information. For ChapProcessCodecID = 1, it is the "DVD level" equivalent; see Section 20.3 on DVD menus.
-
id / type: 0x6911 / master path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess\ChapPr ocessCommand definition: Contains all the commands associated with the Atom.
-
id / type: 0x6922 / uinteger path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess\ChapPr ocessCommand\ChapProcessTime minOccurs / maxOccurs: 1 / 1 definition: Defines when the process command SHOULD be handled. restrictions: See Table 32. +=======+===============================+ | value | label | +=======+===============================+ | 0 | during the whole chapter | +-------+-------------------------------+ | 1 | before starting playback | +-------+-------------------------------+ | 2 | after playback of the chapter | +-------+-------------------------------+
Table 32: ChapProcessTime Values
-
id / type: 0x6933 / binary path: \Segment\Chapters\EditionEntry\+ChapterAtom\ChapProcess\ChapPr ocessCommand\ChapProcessData minOccurs / maxOccurs: 1 / 1 definition: Contains the command information. The data SHOULD be interpreted depending on the ChapProcessCodecID value. For ChapProcessCodecID = 1, the data correspond to the binary DVD cell pre/post commands; see Section 20.3 on DVD menus.
5.1.8. Tags Element
-
id / type: 0x1254C367 / master path: \Segment\Tags definition: Element containing metadata describing Tracks, Editions, Chapters, Attachments, or the Segment as a whole. A list of valid tags can be found in [MatroskaTags].
5.1.8.1. Tag Element
-
id / type: 0x7373 / master path: \Segment\Tags\Tag minOccurs: 1 definition: A single metadata descriptor.
5.1.8.1.1. Targets Element
-
id / type: 0x63C0 / master path: \Segment\Tags\Tag\Targets minOccurs / maxOccurs: 1 / 1 definition: Specifies which other elements the metadata represented by the tag value applies to. If empty or omitted, then the tag value describes everything in the Segment.
-
id / type / default: 0x68CA / uinteger / 50 range: not 0 (1-18446744073709551615) path: \Segment\Tags\Tag\Targets\TargetTypeValue minOccurs / maxOccurs: 1 / 1 definition: A number to indicate the logical level of the target. defined values: See Table 33. Additional values can be registered in the "Matroska Tags Target Types" registry defined in Section 27.13. usage notes: The TargetTypeValue values are meant to be compared. Higher values MUST correspond to a logical level that contains the lower logical level TargetTypeValue values. +=======+==========================+================================+ | value | label | definition | +=======+==========================+================================+ | 70 | COLLECTION | The highest hierarchical level | | | | that tags can describe. | +-------+--------------------------+--------------------------------+ | 60 | EDITION / ISSUE / | A list of lower levels grouped | | | VOLUME / OPUS / | together. | | | SEASON / SEQUEL | | +-------+--------------------------+--------------------------------+ | 50 | ALBUM / OPERA / | The most common grouping level | | | CONCERT / MOVIE / | of music and video (e.g., an | | | EPISODE | episode for TV series). | +-------+--------------------------+--------------------------------+ | 40 | PART / SESSION | When an album or episode has | | | | different logical parts. | +-------+--------------------------+--------------------------------+ | 30 | TRACK / SONG / | The common parts of an album | | | CHAPTER | or movie. | +-------+--------------------------+--------------------------------+ | 20 | SUBTRACK / | Corresponds to parts of a | | | MOVEMENT / SCENE | track for audio, such as a | | | | movement or scene in a movie. | +-------+--------------------------+--------------------------------+ | 10 | SHOT | The lowest hierarchy found in | | | | music or movies. | +-------+--------------------------+--------------------------------+
Table 33: TargetTypeValue Values
-
id / type: 0x63CA / string path: \Segment\Tags\Tag\Targets\TargetType maxOccurs: 1 definition: An informational string that can be used to display the logical level of the target, such as "ALBUM", "TRACK", "MOVIE", "CHAPTER", etc. restrictions: See Table 34. +============+====================+ | value | label | +============+====================+ | COLLECTION | TargetTypeValue 70 | +------------+--------------------+ | EDITION | TargetTypeValue 60 | +------------+--------------------+ | ISSUE | TargetTypeValue 60 | +------------+--------------------+ | VOLUME | TargetTypeValue 60 | +------------+--------------------+ | OPUS | TargetTypeValue 60 | +------------+--------------------+ | SEASON | TargetTypeValue 60 | +------------+--------------------+ | SEQUEL | TargetTypeValue 60 | +------------+--------------------+ | ALBUM | TargetTypeValue 50 | +------------+--------------------+ | OPERA | TargetTypeValue 50 | +------------+--------------------+ | CONCERT | TargetTypeValue 50 | +------------+--------------------+ | MOVIE | TargetTypeValue 50 | +------------+--------------------+ | EPISODE | TargetTypeValue 50 | +------------+--------------------+ | PART | TargetTypeValue 40 | +------------+--------------------+ | SESSION | TargetTypeValue 40 | +------------+--------------------+ | TRACK | TargetTypeValue 30 | +------------+--------------------+ | SONG | TargetTypeValue 30 | +------------+--------------------+ | CHAPTER | TargetTypeValue 30 | +------------+--------------------+ | SUBTRACK | TargetTypeValue 20 | +------------+--------------------+ | MOVEMENT | TargetTypeValue 20 | +------------+--------------------+ | SCENE | TargetTypeValue 20 | +------------+--------------------+ | SHOT | TargetTypeValue 10 | +------------+--------------------+
Table 34: TargetType Values
-
id / type / default: 0x63C5 / uinteger / 0 path: \Segment\Tags\Tag\Targets\TagTrackUID definition: A UID that identifies the Track(s) that the tags belong to. usage notes: If the value is 0 at this level, the tags apply to all tracks in the Segment. If set to any other value, it MUST match the TrackUID value of a track found in this Segment.
-
id / type / default: 0x63C9 / uinteger / 0 path: \Segment\Tags\Tag\Targets\TagEditionUID definition: A UID that identifies the EditionEntry(s) that the tags belong to. usage notes: If the value is 0 at this level, the tags apply to all editions in the Segment. If set to any other value, it MUST match the EditionUID value of an edition found in this Segment.
-
id / type / default: 0x63C4 / uinteger / 0 path: \Segment\Tags\Tag\Targets\TagChapterUID definition: A UID that identifies the Chapter(s) that the tags belong to. usage notes: If the value is 0 at this level, the tags apply to all chapters in the Segment. If set to any other value, it MUST match the ChapterUID value of a chapter found in this Segment.
-
id / type / default: 0x63C6 / uinteger / 0 path: \Segment\Tags\Tag\Targets\TagAttachmentUID definition: A UID that identifies the Attachment(s) that the tags belong to. usage notes: If the value is 0 at this level, the tags apply to all the attachments in the Segment. If set to any other value, it MUST match the FileUID value of an attachment found in this Segment.
5.1.8.1.2. SimpleTag Element
-
id / type: 0x67C8 / master path: \Segment\Tags\Tag\+SimpleTag minOccurs: 1 recursive: True definition: Contains general information about the target.
-
id / type: 0x45A3 / utf-8 path: \Segment\Tags\Tag\+SimpleTag\TagName minOccurs / maxOccurs: 1 / 1 definition: The name of the tag value that is going to be stored.
-
id / type / default: 0x447A / string / und path: \Segment\Tags\Tag\+SimpleTag\TagLanguage minOccurs / maxOccurs: 1 / 1 definition: Specifies the language of the specified tag in the Matroska languages form; see Section 12 on language codes. This element MUST be ignored if the TagLanguageBCP47 element is used within the same SimpleTag element.
-
id / type: 0x447B / string path: \Segment\Tags\Tag\+SimpleTag\TagLanguageBCP47 maxOccurs: 1 minver: 4 definition: The language used in the TagString, in the form defined in [RFC5646]; see Section 12 on language codes. If this element is used, then any TagLanguage elements used in the same SimpleTag MUST be ignored.
-
id / type / default: 0x4484 / uinteger / 1 range: 0-1 path: \Segment\Tags\Tag\+SimpleTag\TagDefault minOccurs / maxOccurs: 1 / 1 definition: A boolean value to indicate if this is the default/ original language to use for the given tag.
-
id / type: 0x4487 / utf-8 path: \Segment\Tags\Tag\+SimpleTag\TagString maxOccurs: 1 definition: The tag value.
-
id / type: 0x4485 / binary path: \Segment\Tags\Tag\+SimpleTag\TagBinary maxOccurs: 1 definition: The tag value if it is binary. Note that this cannot be used in the same SimpleTag as TagString.
6. Matroska Element Ordering
-
With the exceptions of the EBML Header and the CRC-32 element, the EBML specification [RFC8794] does not require any particular storage order for elements. However, this specification defines mandates and recommendations for ordering certain elements to facilitate better playback, seeking, and editing efficiency. This section describes and offers rationale for ordering requirements and recommendations for Matroska.
6.1. Top-Level Elements
-
The Info element is the only REQUIRED Top-Level Element in a Matroska file. To be playable, Matroska MUST also contain at least one Tracks element and Cluster element. The first Info element and the first Tracks element either MUST be stored before the first Cluster element or SHALL both be referenced by a SeekHead element occurring before the first Cluster element.
All Top-Level Elements MUST use a 4-octet EBML Element ID.
When using Medium Linking, chapters are used to reference other Segments to play in a given order (see Section 17.2). A Segment containing these Linked Chapters does not require a Tracks element or a Cluster element.
It is possible to edit a Matroska file after it has been created. For example, chapters, tags, or attachments can be added. When new Top-Level Elements are added to a Matroska file, the SeekHead element(s) MUST be updated so that the SeekHead element(s) itemizes the identity and position of all Top-Level Elements.
Editing, removing, or adding elements to a Matroska file often requires that some existing elements be voided or extended. Transforming the existing elements into Void elements as padding can be used as a method to avoid moving large amounts of data around.
6.2. CRC-32
-
As noted by the EBML specification [RFC8794], if a CRC-32 element is used, then the CRC-32 element MUST be the first ordered element within its Parent Element.
In Matroska, all Top-Level Elements of an EBML Document SHOULD include a CRC-32 element as their first Child Element. The Segment element, which is the Root Element, SHOULD NOT have a CRC-32 element.
6.3. SeekHead
-
If used, the first SeekHead element MUST be the first non-CRC-32 Child element of the Segment element. If a second SeekHead element is used, then the first SeekHead element MUST reference the identity and position of the second SeekHead element.
Additionally, the second SeekHead element MUST only reference Cluster elements and not any other Top-Level Element already contained within the first SeekHead element.
The second SeekHead element MAY be stored in any order relative to the other Top-Level Elements. Whether one or two SeekHead elements are used, the SeekHead element(s) MUST collectively reference the identity and position of all Top-Level Elements except for the first SeekHead element.
6.4. Cues (Index)
-
The Cues element is RECOMMENDED to optimize seeking access in Matroska. It is programmatically simpler to add the Cues element after all Cluster elements have been written because this does not require a prediction of how much space to reserve before writing the Cluster elements. However, storing the Cues element before the Cluster elements can provide some seeking advantages. If the Cues element is present, then it SHOULD either be stored before the first Cluster element or be referenced by a SeekHead element.
6.5. Info
-
The first Info element SHOULD occur before the first Tracks element and first Cluster element except when referenced by a SeekHead element.
6.6. Chapters Element
-
The Chapters element SHOULD be placed before the Cluster element(s). The Chapters element can be used during playback even if the user does not need to seek. It immediately gives the user information about what section is being read and what other sections are available.
In the case of Ordered Chapters, it is RECOMMENDED to evaluate the logical linking before playing. The Chapters element SHOULD be placed before the first Tracks element and after the first Info element.
6.7. Attachments
-
The Attachments element is not intended to be used by default when playing the file but could contain information relevant to the content, such as cover art or fonts. Cover art is useful even before the file is played, and fonts could be needed before playback starts for the initialization of subtitles. The Attachments element MAY be placed before the first Cluster element; however, if the Attachments element is likely to be edited, then it SHOULD be placed after the last Cluster element.
6.8. Tags
-
The Tags element is most subject to changes after the file was originally created. For easier editing, the Tags element can be placed at the end of the Segment element, even after the Attachments element. On the other hand, it is inconvenient to have to seek in the Segment for tags, especially for network streams; thus, it's better if the Tags element is found early in the stream. When editing the Tags element, the original Tags element at the beginning can be overwritten with a Void element and a new Tags element written at the end of the Segment element. The file and Segment sizes will only marginally change.
7. Matroska Versioning
-
Matroska is based on the principle that a reading application does not have to support 100% of the specifications in order to be able to play the file. Therefore, a Matroska file contains version indicators that tell a reading application what to expect.
It is possible and valid to have the version fields indicate that the file contains Matroska elements from a higher specification version number while signaling that a reading application MUST only support a lower version number properly in order to play it back (possibly with a reduced feature set).
The EBML Header of each Matroska document informs the reading application on what version of Matroska to expect. The elements within the EBML Header with jurisdiction over this information are DocTypeVersion and DocTypeReadVersion.
DocTypeVersion MUST be equal to or greater than the highest Matroska version number of any element present in the Matroska file. For example, a file using the SimpleBlock element (Section 5.1.3.4) MUST have a DocTypeVersion equal to or greater than 2. A file containing CueRelativePosition elements (Section 5.1.5.1.2.3) MUST have a DocTypeVersion equal to or greater than 4.
The DocTypeReadVersion MUST contain the minimum version number that a reading application can minimally support in order to play the file back -- optionally with a reduced feature set. For example, if a file contains only elements of version 2 or lower except for CueRelativePosition (which is a version 4 Matroska element), then DocTypeReadVersion SHOULD still be set to 2 and not 4 because evaluating CueRelativePosition is not necessary for standard playback -- it makes seeking more precise if used.
A reading application supporting Matroska version V MUST NOT refuse to read a file with DocReadTypeVersion equal to or lower than V, even if DocTypeVersion is greater than V.
A reading application supporting at least Matroska version V and reading a file whose DocTypeReadVersion field is equal to or lower than V MUST skip Matroska/EBML elements it encounters but does not know about if that unknown element fits into the size constraints set by the current Parent Element.
8. Stream Copy
-
It is sometimes necessary to create a Matroska file from another Matroska file, for example, to add subtitles in a language or to edit out a portion of the content. Some values from the original Matroska file need to be kept the same in the destination file. For example, the SamplingFrequency of an audio track wouldn't change between the two files. Some other values may change between the two files, for example, the TrackNumber of an audio track when another track has been added.
An element is marked with a property "stream copy: True" when the values of that element need to be kept identical between the source and destination files. If that property is not set, elements may or may not keep the same value between the source and destination files.
9. DefaultDecodedFieldDuration
-
The DefaultDecodedFieldDuration element can signal to the displaying application how often fields of a video sequence will be available for displaying. It can be used for both interlaced and progressive content.
If the video sequence is signaled as interlaced (Section 5.1.4.1.28.1), then DefaultDecodedFieldDuration equals the period between two successive fields at the output of the decoding process. For video sequences signaled as progressive, DefaultDecodedFieldDuration is half of the period between two successive frames at the output of the decoding process.
These values are valid at the end of the decoding process before post-processing (such as deinterlacing or inverse telecine) is applied.
Examples:
* Blu-ray movie: 1000000000 ns/(48/1.001) = 20854167 ns * PAL broadcast/DVD: 1000000000 ns/(50/1.000) = 20000000 ns * N/ATSC broadcast: 1000000000 ns/(60/1.001) = 16683333 ns * Hard-telecined DVD: 1000000000 ns/(60/1.001) = 16683333 ns (60 encoded interlaced fields per second) * Soft-telecined DVD: 1000000000 ns/(60/1.001) = 16683333 ns (48 encoded interlaced fields per second, with "repeat_first_field = 1")
10. Cluster Blocks
-
Frames using references SHOULD be stored in "coding order" (i.e., the references first and then the frames referencing them). A consequence is that timestamps might not be consecutive. However, a frame with a past timestamp MUST reference a frame already known; otherwise, it is considered bad/void.
Matroska has two similar ways to store frames in a block:
- in a Block that is contained inside a BlockGroup
- in a SimpleBlock that is directly in the Cluster
The SimpleBlock is usually preferred unless some extra elements of the BlockGroup need to be used. A Matroska Reader MUST support both types of blocks.
Each block contains the same parts in the following order:
- a variable-length header
* the lacing information (optional)
- the consecutive frame(s)
The block header starts with the number of the Track it corresponds to. The value MUST correspond to the TrackNumber (Section 5.1.4.1.1) of a TrackEntry of the Segment.
The TrackNumber is coded using the Variable-Size Integer (VINT) mechanism described in Section 4 of [RFC8794]. To save space, the shortest VINT form SHOULD be used. The value can be coded using up to 8 octets. This is the only element with a variable size in the block header.
The timestamp is expressed in Track Ticks; see Section 11.1. The value is stored as a signed value on 16 bits.
10.1. Block Structure
-
This section describes the binary data contained in the Block element (Section 5.1.3.5.1). Bit 0 is the most significant bit.
As the TrackNumber size can vary between 1 and 8 octets, there are 8 different sizes for the Block header. The definitions for TrackNumber sizes of 1 and 2 are provided; the other variants can be deduced by extending the size of the TrackNumber by multiples of 8 bits.
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | |I|LAC|U| | Track Number | Timestamp | Rsvrd |N|ING|N| | | | |V| |U| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Block Header with 1-Octet TrackNumber
-
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Track Number | Timestamp | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |I|LAC|U| | Rsvrd |N|ING|N| ... | |V| |U| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Block Header with 2-Octet TrackNumber
-
where:
Track Number: 8, 16, 24, 32, 40, 48, or 56 bits. An EBML VINT-coded track number. Timestamp: 16 bits. Signed timestamp in Track Ticks. Rsvrd: 4 bits. Reserved bits MUST be set to 0. INV: 1 bit. Invisible; The codec SHOULD decode this frame but not display it. LACING: 2 bits. Uses lacing mode. 00b: no lacing (Section 10.3.1) 01b: Xiph lacing (Section 10.3.2) 11b: EBML lacing (Section 10.3.3) 10b: fixed-size lacing (Section 10.3.4) UNU: 1 bit. Unused bit.The remaining data in the Block corresponds to the lacing data and frames usage as described in each respective lacing mode (see Section 10.3).
10.2. SimpleBlock Structure
-
This section describes the binary data contained in the SimpleBlock element (Section 5.1.3.4). Bit 0 is the most significant bit.
The SimpleBlock structure is inspired by the Block structure; see Section 10.1. The main differences are the added Keyframe flag and Discardable flag. Otherwise, everything is the same.
As the TrackNumber size can vary between 1 and 8 octets, there are 8 different sizes for the SimpleBlock header. The definitions for TrackNumber sizes of 1 and 2 are provided; the other variants can be deduced by extending the size of the TrackNumber by multiples of 8 bits.
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | |K| |I|LAC|D| | Track Number | Timestamp |E|Rsvrd|N|ING|I| | | |Y| |V| |S| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: SimpleBlock Header with 1-Octet TrackNumber
-
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Track Number | Timestamp | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |K| |I|LAC|D| |E|Rsvrd|N|ING|I| ... |Y| |V| |S| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14: SimpleBlock Header with 2-Octet TrackNumber
-
where:
Track Number: 8, 16, 24, 32, 40, 48, or 56 bits. An EBML VINT-coded track number. Timestamp: 16 bits. Signed timestamp in Track Ticks. KEY: 1 bit. Keyframe; Set when the Block contains only keyframes. Rsvrd: 3 bits. Reserved bits MUST be set to 0. INV: 1 bit. Invisible; the codec SHOULD decode this frame but not display it. LACING: 2 bits. Uses lacing mode. 00b: no lacing (Section 10.3.1) 01b: Xiph lacing (Section 10.3.2) 11b: EBML lacing (Section 10.3.3) 10b: fixed-size lacing (Section 10.3.4) DIS: 1 bit. Discardable; The frames of the Block can be discarded during playing if needed.The remaining data in the SimpleBlock corresponds to the lacing data and frames usage as described in each respective lacing mode (see Section 10.3).
10.3. Block Lacing
-
Lacing is a mechanism to save space when storing data. It is typically used for small blocks of data (referred to as frames in Matroska). It packs multiple frames into a single Block or SimpleBlock.
Lacing MUST NOT be used to store a single frame in a Block or SimpleBlock.
There are three types of lacing:
- Xiph, which is inspired by what is found in the Ogg container [RFC3533]
- EBML, which is the same with sizes coded differently
- Fixed-size, where the size is not coded
When lacing is not used, i.e., to store a single frame, the lacing bits (bits 5 and 6) of the Block or SimpleBlock MUST be set to zero.
For example, a user wants to store three frames of the same track. The first frame is 800 octets long, the second is 500 octets long, and the third is 1000 octets long. Because these frames are small, they can be stored in a lace to save space.
It is possible to not use lacing at all and just store a single frame without any extra data. When the FlagLacing (Section 5.1.4.1.12) is set to 0, all blocks of that track MUST NOT use lacing.
10.3.1. No Lacing
-
When no lacing is used, the number of frames in the lace is omitted, and only one frame can be stored in the Block. The LACING bits of the Block Header flags are set to 00b.
The Block for an 800-octet frame is as follows:
+=============+=========+===================+ | Block Octet | Value | Description | +=============+=========+===================+ | 4-803 | <frame> | Single frame data | +-------------+---------+-------------------+
Table 35: No Lacing
-
When a Block contains a single frame, it MUST use this "no lacing" mode.
10.3.2. Xiph Lacing
-
The Xiph lacing uses the same coding of size as found in the Ogg container [RFC3533]. The LACING bits of the Block Header flags are set to 01b.
The Block data with laced frames is stored as follows:
- Lacing Head on 1 Octet: Number of frames in the lace minus 1.
- Lacing size of each frame except the last one.
- Binary data of each frame consecutively.
The lacing size is split into 255 values, stored as unsigned octets -- for example, 500 is coded 255;245 or [0xFF 0xF5]. A frame with a size multiple of 255 is coded with a 0 at the end of the size -- for example, 765 is coded 255;255;255;0 or [0xFF 0xFF 0xFF 0x00].
The size of the last frame is deduced from the size remaining in the Block after the other frames.
Because large sizes result in large coding of the sizes, it is RECOMMENDED to use Xiph lacing only with small frames.
In our example, the 800-, 500-, and 1000-octet frames are stored with Xiph lacing in a Block as follows:
+==============+=====================+==========================+ | Block Octets | Value | Description | +==============+=====================+==========================+ | 4 | 0x02 | Number of frames minus 1 | +--------------+---------------------+--------------------------+ | 5-8 | 0xFF 0xFF 0xFF 0x23 | Size of the first frame | | | | (255;255;255;35) | +--------------+---------------------+--------------------------+ | 9-10 | 0xFF 0xF5 | Size of the second frame | | | | (255;245) | +--------------+---------------------+--------------------------+ | 11-810 | | First frame data | +--------------+---------------------+--------------------------+ | 811-1310 | | Second frame data | +--------------+---------------------+--------------------------+ | 1311-2310 | | Third frame data | +--------------+---------------------+--------------------------+
Table 36: Xiph Lacing Example
-
The Block is 2311 octets, and the last frame starts at 1311, so we can deduce that the size of the last frame is 2311 - 1311 = 1000.
10.3.3. EBML Lacing
-
The EBML lacing encodes the frame size with an EBML-like encoding [RFC8794]. The LACING bits of the Block Header flags are set to 11b.
The Block data with laced frames is stored as follows:
- Lacing Head on 1 Octet: Number of frames in the lace minus 1.
- Lacing size of each frame except the last one.
- Binary data of each frame consecutively.
The first frame size is encoded as an EBML VINT value. The remaining frame sizes are encoded as signed values using the difference between the frame size and the previous frame size. These signed values are encoded as VINT, with a mapping from signed to unsigned numbers. Decoding the unsigned number stored in the VINT to a signed number is done by subtracting 2^((7*n)-1)-1, where n is the octet size of the VINT.
+===================================+======================+ | Bit Representation of Signed VINT | Possible Value Range | +===================================+======================+ | 1xxx xxxx | 2^7 values from | | | -(2^6-1) to 2^6 | +-----------------------------------+----------------------+ | 01xx xxxx xxxx xxxx | 2^14 values from | | | -(2^13-1) to 2^13 | +-----------------------------------+----------------------+ | 001x xxxx xxxx xxxx xxxx xxxx | 2^21 values from | | | -(2^20-1) to 2^20 | +-----------------------------------+----------------------+ | 0001 xxxx xxxx xxxx xxxx xxxx | 2^28 values from | | xxxx xxxx | -(2^27-1) to 2^27 | +-----------------------------------+----------------------+ | 0000 1xxx xxxx xxxx xxxx xxxx | 2^35 values from | | xxxx xxxx xxxx xxxx | -(2^34-1) to 2^34 | +-----------------------------------+----------------------+
Table 37: EBML Lacing Signed VINT Bits Usage
-
In our example, the 800-, 500-, and 1000-octet frames are stored with EBML lacing in a Block as follows:
+==============+===========+=====================================+ | Block Octets | Value | Description | +==============+===========+=====================================+ | 4 | 0x02 | Number of frames minus 1 | +--------------+-----------+-------------------------------------+ | 5-6 | 0x43 0x20 | Size of the first frame (800 = | | | | 0x320 + 0x4000) | +--------------+-----------+-------------------------------------+ | 7-8 | 0x5E 0xD3 | Size of the second frame (500 - 800 | | | | = -300 = - 0x12C + 0x1FFF + 0x4000) | +--------------+-----------+-------------------------------------+ | 8-807 | <frame1> | First frame data | +--------------+-----------+-------------------------------------+ | 808-1307 | <frame2> | Second frame data | +--------------+-----------+-------------------------------------+ | 1308-2307 | <frame3> | Third frame data | +--------------+-----------+-------------------------------------+
Table 38: EBML Lacing Example
-
The Block is 2308 octets, and the last frame starts at 1308, so we can deduce that the size of the last frame is 2308 - 1308 = 1000.
10.3.4. Fixed-size Lacing
-
Fixed-size lacing doesn't store the frame size; rather, it only stores the number of frames in the lace. Each frame MUST have the same size. The frame size of each frame is deduced from the total size of the Block. The LACING bits of the Block Header flags are set to 10b.
The Block data with laced frames is stored as follows:
- Lacing Head on 1 Octet: Number of frames in the lace minus 1.
- Binary data of each frame consecutively.
For example, for three frames that are 800 octets each:
+==============+==========+==========================+ | Block Octets | Value | Description | +==============+==========+==========================+ | 4 | 0x02 | Number of frames minus 1 | +--------------+----------+--------------------------+ | 5-804 | <frame1> | First frame data | +--------------+----------+--------------------------+ | 805-1604 | <frame2> | Second frame data | +--------------+----------+--------------------------+ | 1605-2404 | <frame3> | Third frame data | +--------------+----------+--------------------------+
Table 39: Fixed-Size Lacing Example
-
This gives a Block of 2405 octets. When reading the Block, we find that there are three frames (Octet 4). The data start at Octet 5, so the size of each frame is (2405 - 5) / 3 = 800.
10.3.5. Laced Frames Timestamp
-
A Block only contains a single timestamp value. But when lacing is used, it contains more than one frame. Each frame originally has its own timestamp, or Presentation Timestamp (PTS). That timestamp applies to the first frame in the lace.
In the lace, each frame after the first one has an underdetermined timestamp. However, each of these frames MUST be contiguous -- i.e., the decoded data MUST NOT contain any gap between them. If there is a gap in the stream, the frames around the gap MUST NOT be in the same Block.
Lacing is only useful for small contiguous data to save space. This is usually the case for audio tracks and not the case for video (which use a lot of data) or subtitle tracks (which have long gaps). For audio, there is usually a fixed output sampling frequency for the whole track, so the decoder should be able to recover the timestamp of each sample, knowing each output sample is contiguous with a fixed frequency. For subtitles, this is usually not the case, so lacing SHOULD NOT be used.
10.4. Random Access Points
-
Random Access Points (RAPs) are positions where the parser can seek to and start playback without decoding what was before. In Matroska, BlockGroups and SimpleBlocks can be RAPs. To seek to these elements, it is still necessary to seek to the Cluster containing them, read the Cluster Timestamp, and start playback from the BlockGroup or SimpleBlock that is a RAP.
Because a Matroska File is usually composed of multiple tracks playing at the same time -- video, audio, and subtitles -- to seek properly to a RAP, each selected track must be taken into account. Usually, all audio and subtitle BlockGroups or SimpleBlocks are RAPs. They are independent of each other and can be played randomly.
On the other hand, video tracks often use references to previous and future frames for better coding efficiency. Frames with such references MUST either contain one or more ReferenceBlock elements in their BlockGroup or MUST be marked as non-keyframe in a SimpleBlock; see Section 10.2.
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- References a Block 40 Track Ticks before this one --> <ReferenceBlock>-40</ReferenceBlock> <Block/> </BlockGroup> ... </Cluster>-
Figure 15: BlockGroup with a Frame That References Another Frame,
-
with the EBML Tree Shown as XML
-
<Cluster> <Timestamp>123456</Timestamp> <SimpleBlock/> (octet 3 bit 0 not set) ... </Cluster>
Figure 16: SimpleBlock with a Frame That References Another
Frame, with the EBML Tree Shown as XML
-
Frames that are RAPs (i.e., frames that don't depend on other frames) MUST set the keyframe flag if they are in a SimpleBlock or their parent BlockGroup MUST NOT contain a ReferenceBlock.
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- No ReferenceBlock allowed in this BlockGroup --> <Block/> </BlockGroup> ... </Cluster>
Figure 17: BlockGroup with a Frame That References No Other
Frame, with the EBML Tree Shown as XML
-
<Cluster> <Timestamp>123456</Timestamp> <SimpleBlock/> (octet 3 bit 0 set) ... </Cluster>
Figure 18: SimpleBlock with a Frame That References No Other
Frame, with the EBML Tree Shown as XML
-
There may be cases where the use of BlockGroup is necessary, as the frame may need a BlockDuration, BlockAdditions, CodecState, or DiscardPadding element. For those cases, a SimpleBlock MUST NOT be used; the reference information SHOULD be recovered for non-RAP frames.
<Cluster> <Timestamp>123456</Timestamp> <SimpleBlock/> (octet 3 bit 0 not set) ... </Cluster>
Figure 19: SimpleBlock with a Frame That References Another
Frame, with the EBML Tree Shown as XML
-
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- ReferenceBlock value recovered based on the codec --> <ReferenceBlock>-40</ReferenceBlock> <BlockDuration>20</BlockDuration> <Block/> </BlockGroup> ... </Cluster>-
Figure 20: Same Frame That References Another Frame Put inside a BlockGroup to Add BlockDuration, with the EBML Tree Shown as XML
When a frame in a BlockGroup is not a RAP, the BlockGroup MUST contain at least a ReferenceBlock. The ReferenceBlocks MUST be used in one of the following ways:
- each reference frame listed as a ReferenceBlock,
- some referenced frames listed as a ReferenceBlock, even if the timestamp value is accurate, or
- one ReferenceBlock with the timestamp value "0" corresponding to a self or unknown reference.
The lack of ReferenceBlock would mean such a frame is a RAP, and seeking on that frame that actually depends on other frames may create a bogus output or even crash.
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- ReferenceBlock value not recovered from the codec --> <ReferenceBlock>0</ReferenceBlock> <BlockDuration>20</BlockDuration> <Block/> </BlockGroup> ... </Cluster>-
Figure 21: Same Frame That References Another Frame Put inside a
BlockGroup, but the Reference Could Not Be Recovered, with the
-
EBML Tree Shown as XML
-
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- References a Block 80 Track Ticks before this one --> <ReferenceBlock>-80</ReferenceBlock> <!-- References a Block 40 Track Ticks after this one --> <ReferenceBlock>40</ReferenceBlock> <Block/> </BlockGroup> ... </Cluster>
Figure 22: BlockGroup with a Frame That References Two Other
Frames, with the EBML Tree Shown as XML
-
Intra-only video frames, such as the ones found in AV1 or VP9, can be decoded without any other frame, but they don't reset the codec state. Thus, seeking to these frames is not possible, as the next frames may need frames that are not known from this seeking point. Such intra-only frames MUST NOT be considered as keyframes, so the keyframe flag MUST NOT be set in the SimpleBlock or a ReferenceBlock MUST be used to signify the frame is not a RAP. The timestamp value of the ReferenceBlock MUST be "0", meaning it's referencing itself.
<Cluster> <Timestamp>123456</Timestamp> <BlockGroup> <!-- References itself to mark it should not be used as RAP --> <ReferenceBlock>0</ReferenceBlock> <Block/> </BlockGroup> ... </Cluster>-
Figure 23: Intra-Only Frame (Not a RAP), with the EBML Tree Shown
-
as XML
-
Because a video SimpleBlock has less information on references than a video BlockGroup, it is possible to remux a video track using BlockGroup into a SimpleBlock, as long as it doesn't use any other BlockGroup features than ReferenceBlock.
11. Timestamps
-
Historically, timestamps in Matroska were mistakenly called timecodes. The Timestamp element was called Timecode, the TimestampScale element was called TimecodeScale, the TrackTimestampScale element was called TrackTimecodeScale, and the ReferenceTimestamp element was called ReferenceTimeCode.
11.1. Timestamp Ticks
-
All timestamp values in Matroska are expressed in multiples of a tick. They are usually stored as integers. There are three types of ticks possible: Matroska Ticks, Segment Ticks, and Track Ticks.
11.1.1. Matroska Ticks
-
The timestamp value is stored directly in nanoseconds.
The elements storing values in Matroska Ticks/nanoseconds are:
* TrackEntry\DefaultDuration; defined in Section 5.1.4.1.13
- TrackEntry\DefaultDecodedFieldDuration; defined in Section 5.1.4.1.14
* TrackEntry\SeekPreRoll; defined in Section 5.1.4.1.26 * TrackEntry\CodecDelay; defined in Section 5.1.4.1.25 * BlockGroup\DiscardPadding; defined in Section 5.1.3.5.7 * ChapterAtom\ChapterTimeStart; defined in Section 5.1.7.1.4.3 * ChapterAtom\ChapterTimeEnd; defined in Section 5.1.7.1.4.4
11.1.2. Segment Ticks
-
Elements in Segment Ticks involve the use of the TimestampScale element of the Segment to get the timestamp in nanoseconds of the element, with the following formula:
timestamp in nanosecond = element value * TimestampScale
This allows for storage of smaller integer values in the elements.
When using the default value of "1,000,000" for TimestampScale, one Segment Tick represents one millisecond.
The elements storing values in Segment Ticks are:
* Cluster\Timestamp; defined in Section 5.1.3.1
- Info\Duration is stored as a floating-point, but the same formula applies; defined in Section 5.1.2.10
* CuePoint\CueTime; defined in Section 5.1.5.1.1
- CuePoint\CueTrackPositions\CueDuration; defined in Section 5.1.5.1.2.4
* CueReference\CueRefTime; defined in Section 5.1.5.1.1
11.1.3. Track Ticks
-
Elements in Track Ticks involve the use of the TimestampScale element of the Segment and the TrackTimestampScale element of the Track to get the timestamp in nanoseconds of the element, with the following formula:
timestamp in nanoseconds =
-
element value * TrackTimestampScale * TimestampScale
This allows for storage of smaller integer values in the elements. The resulting floating-point values of the timestamps are still expressed in nanoseconds.
When using the default values of "1,000,000" for TimestampScale and "1.0" for TrackTimestampScale, one Track Tick represents one millisecond.
The elements storing values in Track Ticks are:
* Cluster\BlockGroup\Block and Cluster\SimpleBlock timestamps; detailed in Section 11.2 * Cluster\BlockGroup\BlockDuration; defined in Section 5.1.3.5.3 * Cluster\BlockGroup\ReferenceBlock; defined in Section 5.1.3.5.5When the TrackTimestampScale is interpreted as "1.0", Track Ticks are equivalent to Segment Ticks and give an integer value in nanoseconds. This is the most common case as TrackTimestampScale is usually omitted.
A value of TrackTimestampScale other than "1.0" MAY be used to scale the timestamps more in tune with each Track sampling frequency. For historical reasons, a lot of Matroska Readers don't take the TrackTimestampScale value into account. Thus, using a value other than "1.0" might not work in many places.
11.2. Block Timestamps
-
A Block element and SimpleBlock element timestamp is the time when the decoded data of the first frame in the Block/SimpleBlock MUST be presented if the track of that Block/SimpleBlock is selected for playback. This is also known as the Presentation Timestamp (PTS).
The Block element and SimpleBlock element store their timestamps as signed integers, relative to the Cluster\Timestamp value of the Cluster they are stored in. To get the timestamp of a Block or SimpleBlock in nanoseconds, the following formula is used:
( Cluster\Timestamp + ( block timestamp * TrackTimestampScale ) ) * TimestampScale
The Block element and SimpleBlock element store their timestamps as 16-bit signed integers, allowing a range from "-32768" to "+32767" Track Ticks. Although these values can be negative, when added to the Cluster\Timestamp, the resulting frame timestamp SHOULD NOT be negative.
When a CodecDelay element is set, its value MUST be subtracted from each Block timestamp of that track. To get the timestamp in nanoseconds of the first frame in a Block or SimpleBlock, the formula becomes:
( ( Cluster\Timestamp + ( block timestamp * TrackTimestampScale ) ) * TimestampScale ) - CodecDelayThe resulting frame timestamp SHOULD NOT be negative.
During playback, when a frame has a negative timestamp, the content MUST be decoded by the decoder but not played to the user.
11.3. TimestampScale Rounding
-
The default Track Tick duration is one millisecond.
The TimestampScale is a floating-point value that is usually "1.0". But when it's not, the multiplied Block Timestamp is a floating-point value in nanoseconds. The Matroska Reader SHOULD use the nearest rounding value in nanoseconds to get the proper nanosecond timestamp of a Block. This allows some clever TimestampScale values to have a more refined timestamp precision per frame.
12. Language Codes
-
Matroska versions 1 through 3 use language codes that can be either the three-letter bibliographic ISO 639-2 form [ISO639-2] (like "fre" for French) or such a language code followed by a dash and a country code for specialities in languages (like "fre-ca" for Canadian French). The ISO 639-2 Language elements are Language element, TagLanguage element, and ChapLanguage element.
Starting in Matroska version 4, the forms defined in either [ISO639-2] or [RFC5646] MAY be used, although the form in [RFC5646] is RECOMMENDED. The Language elements in the [RFC5646] form are LanguageBCP47 element, TagLanguageBCP47 element, and ChapLanguageBCP47 element. If both an [ISO639-2] Language element and an [RFC5646] Language element are used within the same Parent Element, then the Language element in the [ISO639-2] form MUST be ignored and precedence given to the Language element in the [RFC5646] form.
In this document, "BCP47" in element names refers specifically to [RFC5646], which is part of BCP 47.
13. Country Codes
-
Country codes are the [RFC5646] two-letter region subtags, without the UK exception.
14. Encryption
-
This Matroska specification provides no interoperable solution for securing the data container with any assurances of confidentiality, integrity, authenticity, or authorization. The ContentEncryption element (Section 5.1.4.1.31.8) and associated sub-fields (Section 5.1.4.1.31.9 to Section 5.1.4.1.31.12) are defined only for the benefit of implementers to construct their own proprietary solution or as the basis for further standardization activities. How to use these fields to secure a Matroska data container is out of scope, as are any related issues such as key management and distribution.
A Matroska Reader who encounters containers that use the fields defined in this section MUST rely on out-of-scope guidance to decode the associated content.
Because encryption occurs within the Block element, it is possible to manipulate encrypted streams without decrypting them. The streams could potentially be copied, deleted, cut, appended, or any number of other possible editing techniques without decryption. The data can be used without having to expose it or go through the decrypting process.
Encryption can also be layered within Matroska. This means that two completely different types of encryption can be used, requiring two separate keys to be able to decrypt a stream.
Encryption information is stored in the ContentEncodings element under the ContentEncryption element.
For encryption systems sharing public/private keys, the creation of the keys and the exchange of keys are not covered by this document. They have to be handled by the system using Matroska.
The algorithms described in Table 24 support different modes of operations and key sizes. The specification of these parameters is required for a complete solution but is out of scope of this document and left to the proprietary implementations using them or subsequent profiles of this document.
The ContentEncodingScope element gives an idea of which part of the track is encrypted, but each ContentEncAlgo element and its sub- elements (like AESSettingsCipherMode) define exactly how the encrypted track should be interpreted.
An example of an extension that builds upon these security-related fields in this specification is [WebM-Enc]. It uses AES-CTR, ContentEncAlgo = 5 (Section 5.1.4.1.31.9), and AESSettingsCipherMode = 1 (Section 5.1.4.1.31.12).
A Matroska Writer MUST NOT use insecure cryptographic algorithms to create new archives or streams, but a Matroska Reader MAY support these algorithms to read previously made archives or streams.
15. Image Presentation
15.1. Cropping
-
The PixelCrop elements (PixelCropTop, PixelCropBottom, PixelCropRight, and PixelCropLeft) indicate when, and by how much, encoded video frames SHOULD be cropped for display. These elements allow edges of the frame that are not intended for display (such as the sprockets of a full-frame film scan or the Video ANCillary (VANC) area of a digitized analog videotape) to be stored but hidden. PixelCropTop and PixelCropBottom store an integer of how many rows of pixels SHOULD be cropped from the top and bottom of the image, respectively. PixelCropLeft and PixelCropRight store an integer of how many columns of pixels SHOULD be cropped from the left and right of the image, respectively.
For example, a pillar-boxed video that stores a 1440x1080 visual image within the center of a padded 1920x1080 encoded image may set both PixelCropLeft and PixelCropRight to "240", so a Matroska Player should crop off 240 columns of pixels from the left and right of the encoded image to present the image with the pillar-boxes hidden.
Cropping has to be performed before resizing and the display dimensions given by DisplayWidth, DisplayHeight, and DisplayUnit apply to the already-cropped image.
15.2. Rotation
-
The ProjectionPoseRoll element (Section 5.1.4.1.28.46) can be used to indicate that the image from the associated video track SHOULD be rotated for presentation. For instance, the following example of the Projection element (Section 5.1.4.1.28.41) and the ProjectionPoseRoll element represents a video track where the image SHOULD be presented with a 90-degree counter-clockwise rotation, with the EBML tree shown as XML:
<Projection> <ProjectionPoseRoll>90</ProjectionPoseRoll> </Projection>
Figure 24: Rotation Example
16. Segment Position
-
The Segment Position of an element refers to the position of the first octet of the Element ID of that element, measured in octets, from the beginning of the Element Data section of the containing Segment element. In other words, the Segment Position of an element is the distance in octets from the beginning of its containing Segment element minus the size of the Element ID and Element Data Size of that Segment element. The Segment Position of the first Child Element of the Segment element is 0. An element that is not stored within a Segment element, such as the elements of the EBML Header, do not have a Segment Position.
16.1. Segment Position Exception
-
Elements that are defined to store a Segment Position MAY define reserved values to indicate a special meaning.
16.2. Example of Segment Position
-
This table presents an example of Segment Position by showing a hexadecimal representation of a very small Matroska file with labels to show the offsets in octets. The file contains a Segment element with an Element ID of "0x18538067" and a MuxingApp element with an Element ID of "0x4D80".
0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ 0 |1A|45|DF|A3|8B|42|82|88|6D|61|74|72|6F|73|6B|61| ^ EBML Header 0 | |18|53|80|67| ^ Segment ID 20 |93| ^ Segment Data Size 20 | |15|49|A9|66|8E|4D|80|84|69|65|74|66|57|41|84|69|65|74|66| ^ Start of Segment data 20 | |4D|80|84|69|65|74|66|57|41|84|69|65|74|66| ^ MuxingApp startIn the above example, the Element ID of the Segment element is stored at offset 16, the Element Data Size of the Segment element is stored at offset 20, and the Element Data of the Segment element is stored at offset 21.
The MuxingApp element is stored at offset 26. Since the Segment Position of an element is calculated by subtracting the position of the Element Data of the containing Segment element from the position of that element, the Segment Position of the MuxingApp element in the above example is "26 - 21" or "5".
17. Linked Segments
-
Matroska provides several methods to link two or more Segment elements together to create a Linked Segment. A Linked Segment is a set of multiple Segments linked together into a single presentation by using Hard Linking or Medium Linking.
All Segments within a Linked Segment MUST have a SegmentUUID.
All Segments within a Linked Segment SHOULD be stored within the same directory or be quickly accessible based on their SegmentUUID in order to have a seamless transition between segments.
All Segments within a Linked Segment MAY set a SegmentFamily with a common value to make it easier for a Matroska Player to know which Segments are meant to be played together.
The SegmentFilename, PrevFilename, and NextFilename elements MAY also give hints on the original filenames that were used when the Segment links were created, in case some SegmentUUIDs are damaged.
17.1. Hard Linking
-
Hard Linking, also called "splitting", is the process of creating a Linked Segment by linking multiple Segment elements using the NextUUID and PrevUUID elements.
All Segments within a Hard Linked Segment MUST use the same Tracks list and TimestampScale.
Within a Linked Segment, the timestamps of Block and SimpleBlock MUST consecutively follow the timestamps of Block and SimpleBlock from the previous Segment in linking order.
With Hard Linking, the chapters of any Segment within the Linked Segment MUST only reference the current Segment. The NextUUID and PrevUUID reference the respective SegmentUUID values of the next and previous Segments.
The first Segment of a Linked Segment MUST NOT have a PrevUUID element. The last Segment of a Linked Segment MUST NOT have a NextUUID element.
For each node of the chain of Segments of a Linked Segment, at least one Segment MUST reference the other Segment within the chain.
In a chain of Segments of a Linked Segment, the NextUUID always takes precedence over the PrevUUID. Thus, if SegmentA has a NextUUID to SegmentB and SegmentB has a PrevUUID to SegmentC, the link to use is NextUUID between SegmentA and SegmentB, and SegmentC is not part of the Linked Segment.
If SegmentB has a PrevUUID to SegmentA, but SegmentA has no NextUUID, then the Matroska Player MAY consider these two Segments linked as SegmentA followed by SegmentB.
As an example, three Segments can be Hard Linked as a Linked Segment through cross-referencing each other with SegmentUUID, PrevUUID, and NextUUID as shown in this table:
+==========+================+==================+==================+ |file name |SegmentUUID | PrevUUID | NextUUID | +==========+================+==================+==================+ |start.mkv |71000c23cd310998| Invalid | a77b3598941cb803 | | |53fbc94dd984a5dd| | eac0fcdafe44fac9 | +----------+----------------+------------------+------------------+ |middle.mkv|a77b3598941cb803| 71000c23cd310998 | 6c92285fa6d3e827 | | |eac0fcdafe44fac9| 53fbc94dd984a5dd | b198d120ea3ac674 | +----------+----------------+------------------+------------------+ |end.mkv |6c92285fa6d3e827| a77b3598941cb803 | Invalid | | |b198d120ea3ac674| eac0fcdafe44fac9 | | +----------+----------------+------------------+------------------+
Table 40: Usual Hard Linking UIDs
-
An example where only the NextUUID element is used:
+============+==================+==========+==================+ | file name | SegmentUUID | PrevUUID | NextUUID | +============+==================+==========+==================+ | start.mkv | 71000c23cd310998 | Invalid | a77b3598941cb803 | | | 53fbc94dd984a5dd | | eac0fcdafe44fac9 | +------------+------------------+----------+------------------+ | middle.mkv | a77b3598941cb803 | n/a | 6c92285fa6d3e827 | | | eac0fcdafe44fac9 | | b198d120ea3ac674 | +------------+------------------+----------+------------------+ | end.mkv | 6c92285fa6d3e827 | n/a | Invalid | | | b198d120ea3ac674 | | | +------------+------------------+----------+------------------+
Table 41: Hard Linking without PrevUUID
-
An example where only the PrevUUID element is used:
+============+==================+==================+==========+ | file name | SegmentUUID | PrevUUID | NextUUID | +============+==================+==================+==========+ | start.mkv | 71000c23cd310998 | Invalid | n/a | | | 53fbc94dd984a5dd | | | +------------+------------------+------------------+----------+ | middle.mkv | a77b3598941cb803 | 71000c23cd310998 | n/a | | | eac0fcdafe44fac9 | 53fbc94dd984a5dd | | +------------+------------------+------------------+----------+ | end.mkv | 6c92285fa6d3e827 | a77b3598941cb803 | Invalid | | | b198d120ea3ac674 | eac0fcdafe44fac9 | | +------------+------------------+------------------+----------+
Table 42: Hard Linking without NextUUID
-
An example where only the middle.mkv is using the PrevUUID and NextUUID elements:
+==========+================+==================+==================+ |file name |SegmentUUID | PrevUUID | NextUUID | +==========+================+==================+==================+ |start.mkv |71000c23cd310998| Invalid | n/a | | |53fbc94dd984a5dd| | | +----------+----------------+------------------+------------------+ |middle.mkv|a77b3598941cb803| 71000c23cd310998 | 6c92285fa6d3e827 | | |eac0fcdafe44fac9| 53fbc94dd984a5dd | b198d120ea3ac674 | +----------+----------------+------------------+------------------+ |end.mkv |6c92285fa6d3e827| n/a | Invalid | | |b198d120ea3ac674| | | +----------+----------------+------------------+------------------+
Table 43: Hard Linking with Mixed UID Links
17.2. Medium Linking
-
Medium Linking creates relationships between Segments using Ordered Chapters (Section 20.1.3) and the ChapterSegmentUUID element. A Chapter Edition with Ordered Chapters MAY contain Chapters elements that reference timestamp ranges from other Segments. The Segment referenced by the Ordered Chapter via the ChapterSegmentUUID element SHOULD be played as part of a Linked Segment.
The timestamps of Segment content referenced by Ordered Chapters MUST be adjusted according to the cumulative duration of the previous Ordered Chapters.
As an example, a file named intro.mkv could have a SegmentUUID of "0xb16a58609fc7e60653a60c984fc11ead". Another file called program.mkv could use a Chapter Edition that contains two Ordered Chapters. The first chapter references the Segment of intro.mkv with the use of a ChapterSegmentUUID, ChapterSegmentEditionUID, ChapterTimeStart, and an optional ChapterTimeEnd element. The second chapter references content within the Segment of program.mkv. A Matroska Player SHOULD recognize the Linked Segment created by the use of ChapterSegmentUUID in an enabled Edition and present the reference content of the two Segments as a single presentation.
The ChapterSegmentUUID represents the Segment that holds the content to play in place of the Linked Chapter. The ChapterSegmentUUID MUST NOT be the SegmentUUID of its own Segment.
There are two ways to use a chapter link:
- Linked-Duration linking
- Linked-Edition linking
17.2.1. Linked-Duration
-
A Matroska Player MUST play the content of the Linked Segment from the ChapterTimeStart until the ChapterTimeEnd timestamp in place of the Linked Chapter.
ChapterTimeStart and ChapterTimeEnd represent timestamps in the Linked Segment matching the value of ChapterSegmentUUID. Their values MUST be in the range of the Linked Segment duration.
The ChapterTimeEnd value MUST be set when using Linked-Duration chapter linking. ChapterSegmentEditionUID MUST NOT be set.
17.2.2. Linked-Edition
-
A Matroska Player MUST play the whole Linked Edition of the Linked Segment in place of the Linked Chapter.
ChapterSegmentEditionUID represents a valid Edition from the Linked Segment matching the value of ChapterSegmentUUID.
When using Linked-Edition chapter linking, ChapterTimeEnd is OPTIONAL.
18. Track Flags
18.1. Default Flag
-
The Default flag is a hint for a Matroska Player indicating that a given track SHOULD be eligible to be automatically selected as the default track for a given language. If no tracks in a given language have the Default flag set, then all tracks in that language are eligible for automatic selection. This can be used to indicate that a track provides "regular service" that is suitable for users with default settings, as opposed to specialized services, such as commentary, captions for users with hearing impairments, or descriptive audio.
The Matroska Player MAY override the Default flag for any reason, including user preferences to prefer tracks providing accessibility services.
18.2. Forced Flag
-
The Forced flag tells the Matroska Player that it SHOULD display this subtitle track, even if user preferences usually would not call for any subtitles to be displayed alongside the audio track that is currently selected. This can be used to indicate that a track contains translations of on-screen text or dialogue spoken in a different language than the track's primary language.
18.3. Hearing-Impaired Flag
-
The Hearing-Impaired flag tells the Matroska Player that it SHOULD prefer this track when selecting a default track for a user with a hearing impairment and that it MAY prefer to select a different track when selecting a default track for a user that is not hearing impaired.
18.4. Visual-Impaired Flag
-
The Visual-Impaired flag tells the Matroska Player that it SHOULD prefer this track when selecting a default track for a user with a visual impairment and that it MAY prefer to select a different track when selecting a default track for a user that is not visually impaired.
18.5. Descriptions Flag
-
The Descriptions flag tells the Matroska Player that this track is suitable to play via a text-to-speech system for a user with a visual impairment and that it SHOULD NOT automatically select this track when selecting a default track for a user that is not visually impaired.
18.6. Original Flag
-
The Original flag tells the Matroska Player that this track is in the original language and that it SHOULD prefer this track if configured to prefer original-language tracks of this track's type.
18.7. Commentary Flag
-
The Commentary flag tells the Matroska Player that this track contains commentary on the content.
18.8. Track Operation
-
TrackOperation allows for the combination of multiple tracks to make a virtual one. It uses two separate system to combine tracks. One to create a 3D "composition" (left/right/background planes) and one to simplify join two tracks together to make a single track.
A track created with TrackOperation is a proper track with a UID and all its flags. However, the codec ID is meaningless because each "sub" track needs to be decoded by its own decoder before the "operation" is applied. The Cues elements corresponding to such a virtual track SHOULD be the union of the Cues elements for each of the tracks it's composed of (when the Cues are defined per track).
In the case of TrackJoinBlocks, the Block elements (from BlockGroup and SimpleBlock) of all the tracks SHOULD be used as if they were defined for this new virtual Track. When two Block elements have overlapping start or end timestamps, it's up to the underlying system to either drop some of these frames or render them the way they overlap. This situation SHOULD be avoided when creating such tracks, as you can never be sure of the end result on different platforms.
18.9. Overlay Track
-
An overlay track SHOULD be rendered in the same channel as the track it's linked to. When content is found in such a track, it SHOULD be played on the rendering channel instead of the original track.
18.10. Multi-planar and 3D Videos
-
There are two different ways to compress 3D videos: have each eye track in a separate track and have one track have both eyes combined inside (which is more efficient compression-wise). Matroska supports both ways.
For the single-track variant, there is the StereoMode element, which defines how planes are assembled in the track (mono or left-right combined). Odd values of StereoMode means the left plane comes first for more convenient reading. The pixel count of the track (PixelWidth/PixelHeight) is the raw number of pixels (for example, 3840x1080 for full HD side by side), and the DisplayWidth/ DisplayHeight in pixels is the number of pixels for one plane (1920x1080 for that full HD stream). Old stereo 3D movies were displayed using anaglyph (cyan and red colors separated). For compatibility with such movies, there is a value of the StereoMode that corresponds to anaglyph.
There is also a "packed" mode (values 13 and 14) that consists of packing two frames together in a Block that uses lacing. The first frame is the left eye and the other frame is the right eye (or vice versa). The frames SHOULD be decoded in that order and are possibly dependent on each other (P and B frames).
For separate tracks, Matroska needs to define exactly which track does what. TrackOperation with TrackCombinePlanes does that. For more details, see Section 18.8 on how TrackOperation works.
The 3D support is still in infancy and may evolve to support more features.
The StereoMode used to be part of Matroska v2, but it didn't meet the requirement for multiple tracks. There was also a bug in [libmatroska] prior to 0.9.0 that would save/read it as 0x53B9 instead of 0x53B8; see OldStereoMode (Section 5.1.4.1.28.5). Matroska Readers MAY support these legacy files by checking Matroska v2 or 0x53B9. The older values of StereoMode were 0 (mono), 1 (right eye), 2 (left eye), and 3 (both eyes); these are the only values that can be found in OldStereoMode. They are not compatible with the StereoMode values found in Matroska v3 and above.
19. Default Track Selection
-
This section provides some example sets of Tracks and hypothetical user settings, along with indications of which ones a similarly configured Matroska Player SHOULD automatically select for playback by default in such a situation. A player MAY provide additional settings with more detailed controls for more nuanced scenarios. These examples are provided as guidelines to illustrate the intended usages of the various supported Track flags and their expected behaviors.
Track names are shown in English for illustrative purposes; actual files may have titles in the language of each track or provide titles in multiple languages.
19.1. Audio Selection
-
Example track set:
+===+=====+====+======+========+=======+===============+===========+ |No.|Type |Lang|Layout|Original|Default|Other Flags |Name | +===+=====+====+======+========+=======+===============+===========+ |1 |Video|und |N/A |N/A |N/A |None | | +---+-----+----+------+--------+-------+---------------+-----------+ |2 |Audio|eng |5.1 |1 |1 |None | | +---+-----+----+------+--------+-------+---------------+-----------+ |3 |Audio|eng |2.0 |1 |1 |None | | +---+-----+----+------+--------+-------+---------------+-----------+ |4 |Audio|eng |2.0 |1 |0 |Visual-Impaired|Descriptive| | | | | | | | |audio | +---+-----+----+------+--------+-------+---------------+-----------+ |5 |Audio|esp |5.1 |0 |1 |None | | +---+-----+----+------+--------+-------+---------------+-----------+ |6 |Audio|esp |2.0 |0 |0 |Visual-Impaired|Descriptive| | | | | | | | |audio | +---+-----+----+------+--------+-------+---------------+-----------+ |7 |Audio|eng |2.0 |1 |0 |Commentary |Director's | | | | | | | | |Commentary | +---+-----+----+------+--------+-------+---------------+-----------+ |8 |Audio|eng |2.0 |1 |0 |None |Karaoke | +---+-----+----+------+--------+-------+---------------+-----------+
Table 44: Audio Tracks for Default Selection
-
The table above shows a file with seven audio tracks -- five in English and two in Spanish.
The English tracks all have the Original flag, indicating that English is the original content language.
Generally, the player will first consider the track languages. If the player has an option to prefer original-language audio and the user has enabled it, then it should prefer one of the tracks with the Original flag. If the user has configured to specifically prefer audio tracks in English or Spanish, the player should select one of the tracks in the corresponding language. The player may also wish to prefer a track with the Original flag if no tracks matching any of the user's explicitly preferred languages are available.
Two of the tracks have the Visual-Impaired flag. If the player has been configured to prefer such tracks, it should select one; otherwise, it should avoid them if possible.
If selecting an English track, when other settings have left multiple possible options, it may be useful to exclude the tracks that lack the Default flag. Here, one provides descriptive service for individuals with visual impairments (which has its own flag and may be automatically selected by user configuration but is unsuitable for users with default-configured players), one is a commentary track (which has its own flag and the player may or may not have specialized handling for), and the last contains karaoke versions of the music that plays during the film (which is an unusual specialized audio service that Matroska has no built-in support for indicating, so it's indicated in the track name instead). By not setting the Default flag on these specialized tracks, the file's author hints that they should not be automatically selected by a default- configured player.
Having narrowed its choices down, the example player now may have to select between tracks 2 and 3. The only difference between these tracks is their channel layouts: 2 is 5.1 surround, while 3 is stereo. If the player is aware that the output device is a pair of headphones or stereo speakers, it may wish to prefer the stereo mix automatically. On the other hand, if it knows that the device is a surround system, it may wish to prefer the surround mix.
If the player finishes analyzing all of the available audio tracks and finds that more than one seem equally and maximally preferable, it SHOULD default to the first of the group.
19.2. Subtitle Selection
-
Example track set:
+===+=========+====+========+=======+======+========+==============+ |No.|Type |Lang|Original|Default|Forced|Other | Name | | | | | | | |Flags | | +===+=========+====+========+=======+======+========+==============+ |1 |Video |und |N/A |N/A |N/A |None | | +---+---------+----+--------+-------+------+--------+--------------+ |2 |Audio |fra |1 |1 |N/A |None | | +---+---------+----+--------+-------+------+--------+--------------+ |3 |Audio |por |0 |1 |N/A |None | | +---+---------+----+--------+-------+------+--------+--------------+ |4 |Subtitles|fra |1 |1 |0 |None | | +---+---------+----+--------+-------+------+--------+--------------+ |5 |Subtitles|fra |1 |0 |0 |Hearing-| Captions for | | | | | | | |Impaired| users with | | | | | | | | | hearing | | | | | | | | | impairments | +---+---------+----+--------+-------+------+--------+--------------+ |6 |Subtitles|por |0 |1 |0 |None | | +---+---------+----+--------+-------+------+--------+--------------+ |7 |Subtitles|por |0 |0 |1 |None | Signs | +---+---------+----+--------+-------+------+--------+--------------+ |8 |Subtitles|por |0 |0 |0 |Hearing-| SDH | | | | | | | |Impaired| | +---+---------+----+--------+-------+------+--------+--------------+
Table 45: Subtitle Tracks for Default Selection
-
The table above shows two audio tracks and five subtitle tracks. As we can see, French is the original language.
We'll start by discussing the case where the user prefers French (or original-language) audio (or has explicitly selected the French audio track) and also prefers French subtitles.
In this case, if the player isn't configured to display captions when the audio matches their preferred subtitle languages, the player doesn't need to select a subtitle track at all.
If the user _has_ indicated that they want captions to be displayed, the selection simply comes down to whether hearing-impaired subtitles are preferred.
The situation for a user who prefers Portuguese subtitles starts out somewhat analogous. If they select the original French audio (either by explicit audio language preference, preference for original- language tracks, or explicitly selecting that track), then the selection once again comes down to the hearing-impaired preference.
However, the case where the Portuguese audio track is selected has an important catch: a Forced track in Portuguese is present. This may contain translations of on-screen text from the video track or of portions of the audio that are not translated (music, for instance). This means that even if the user's preferences wouldn't normally call for captions here, the Forced track should be selected nonetheless, rather than selecting no track at all. On the other hand, if the user's preferences _do_ call for captions, the non-Forced tracks should be preferred, as the Forced track will not contain captioning for the dialogue.
20. Chapters
-
The Matroska Chapters system can have multiple Editions, and each Edition can consist of Simple Chapters where a chapter start time is used as a marker in the timeline only. An Edition can be more complex with Ordered Chapters where a chapter end timestamp is additionally used or much more complex with Linked Chapters. The Matroska Chapters system can also have a menu structure borrowed from the DVD-menu system [DVD-Video] or have its own built-in Matroska menu structure.
20.1. EditionEntry
-
The EditionEntry is also called an Edition. An Edition contains a set of Edition flags and MUST contain at least one ChapterAtom element. Chapters are always inside an Edition (or a Chapter itself is part of an Edition). Multiple Editions are allowed. Some of these Editions MAY be ordered and others not.
20.1.1. EditionFlagDefault
-
Only one Edition SHOULD have an EditionFlagDefault flag set to true.
20.1.2. Default Edition
-
The Default Edition is the Edition that a Matroska Player SHOULD use for playback by default.
The first Edition with the EditionFlagDefault flag set to true is the Default Edition.
When all EditionFlagDefault flags are set to false, then the first Edition is the Default Edition.
+===========+=============+=================+ | Edition | FlagDefault | Default Edition | +===========+=============+=================+ | Edition 1 | true | X | +-----------+-------------+-----------------+ | Edition 2 | true | | +-----------+-------------+-----------------+ | Edition 3 | true | | +-----------+-------------+-----------------+
Table 46: Default Edition, All Default
-
+===========+=============+=================+ | Edition | FlagDefault | Default Edition | +===========+=============+=================+ | Edition 1 | false | X | +-----------+-------------+-----------------+ | Edition 2 | false | | +-----------+-------------+-----------------+ | Edition 3 | false | | +-----------+-------------+-----------------+
Table 47: Default Edition, No Default
-
+===========+=============+=================+ | Edition | FlagDefault | Default Edition | +===========+=============+=================+ | Edition 1 | false | | +-----------+-------------+-----------------+ | Edition 2 | true | X | +-----------+-------------+-----------------+ | Edition 3 | false | | +-----------+-------------+-----------------+
Table 48: Default Edition, With Default
20.1.3. EditionFlagOrdered
-
The EditionFlagOrdered flag is a significant feature, as it enables an Edition of Ordered Chapters that defines and arranges a virtual timeline rather than simply labeling points within the timeline. For example, with Editions of Ordered Chapters, a single Matroska file can present multiple edits of a film without duplicating content. Alternatively, if a videotape is digitized in full, one Ordered Edition could present the full content (including colorbars, countdown, slate, a feature presentation, and black frames), while another Edition of Ordered Chapters can use Chapters that only mark the intended presentation with the colorbars and other ancillary visual information excluded. If an Edition of Ordered Chapters is enabled, then the Matroska Player MUST play those Chapters in their stored order from the timestamp marked in the ChapterTimeStart element to the timestamp marked in to ChapterTimeEnd element.
If the EditionFlagOrdered flag evaluates to "0", Simple Chapters are used and only the ChapterTimeStart of a Chapter is used as a chapter mark to jump to the predefined point in the timeline. With Simple Chapters, a Matroska Player MUST ignore certain elements inside a Chapters element. In that case, these elements are informational only.
The following list shows the different Chapters elements only found in Ordered Chapters.
- ChapterAtom\ChapterSegmentUUID
- ChapterAtom\ChapterSegmentEditionUID
- ChapterAtom\ChapProcess
- Info\ChapterTranslate
- TrackEntry\TrackTranslate
Furthermore, there are other EBML elements that could be used if the EditionFlagOrdered evaluates to "1".
20.1.3.1. Ordered-Edition and Matroska Segment Linking
-
Hard Linking: Ordered Chapters supersede the Hard Linking. Medium Linking: Ordered Chapters are used in a normal way and can be combined with the ChapterSegmentUUID element, which establishes a link to another Segment.See Section 17 on Linked Segments for more information about Hard Linking and Medium Linking.
20.2. ChapterAtom
-
The ChapterAtom is also called a Chapter.
20.2.1. ChapterTimeStart
-
ChapterTimeStart is the timestamp of the start of Chapter with nanosecond accuracy and is not scaled by TimestampScale. For Simple Chapters, this is the position of the chapter markers in the timeline.
20.2.2. ChapterTimeEnd
-
ChapterTimeEnd is the timestamp of the end of Chapter with nanosecond accuracy and is not scaled by TimestampScale. The timestamp defined by the ChapterTimeEnd is not part of the Chapter. A Matroska Player calculates the duration of this Chapter using the difference between the ChapterTimeEnd and ChapterTimeStart. The end timestamp MUST be greater than or equal to the start timestamp.
When the ChapterTimeEnd timestamp is equal to the ChapterTimeStart timestamp, the timestamp is included in the Chapter. It can be useful to put markers in a file or add chapter commands with ordered chapter commands without having to play anything; see Section 5.1.7.1.4.14.
+===========+=================+===============+===============+ | Chapter | Start timestamp | End timestamp | Duration | +===========+=================+===============+===============+ | Chapter 1 | 0 | 1000000000 | 1000000000 | +-----------+-----------------+---------------+---------------+ | Chapter 2 | 1000000000 | 5000000000 | 4000000000 | +-----------+-----------------+---------------+---------------+ | Chapter 3 | 6000000000 | 6000000000 | 0 | +-----------+-----------------+---------------+---------------+ | Chapter 4 | 9000000000 | 8000000000 | Invalid | | | | | (-1000000000) | +-----------+-----------------+---------------+---------------+
Table 49: ChapterTimeEnd Usage Possibilities
20.2.3. Nested Chapters
-
A ChapterAtom element can contain other ChapterAtom elements. That element is a Parent Chapter, and the ChapterAtom elements it contains are Nested Chapters.
Nested Chapters can be useful to tag small parts of a Segment that already have tags or add Chapter Codec commands on smaller parts of a Segment that already have Chapter Codec commands.
The ChapterTimeStart of a Nested Chapter MUST be greater than or equal to the ChapterTimeStart of its Parent Chapter.
If the Parent Chapter of a Nested Chapter has a ChapterTimeEnd, the ChapterTimeStart of that Nested Chapter MUST be smaller than or equal to the ChapterTimeEnd of the Parent Chapter.
20.2.4. Nested Chapters in Ordered Chapters
-
The ChapterTimeEnd of the lowest level of Nested Chapters MUST be set for Ordered Chapters.
When used with Ordered Chapters, the ChapterTimeEnd value of a Parent Chapter is useless for playback, as the proper playback sections are described in its Nested Chapters. The ChapterTimeEnd SHOULD NOT be set in Parent Chapters and MUST be ignored for playback.
20.2.5. ChapterFlagHidden
-
Each Chapter's ChapterFlagHidden flag works independently of Parent Chapters. A Nested Chapter with a ChapterFlagHidden flag that evaluates to "0" remains visible in the user interface even if the Parent Chapter's ChapterFlagHidden flag is set to "1".
+==========================+===================+=========+ | Chapter + Nested Chapter | ChapterFlagHidden | visible | +==========================+===================+=========+ | Chapter 1 | 0 | yes | +--------------------------+-------------------+---------+ | Nested Chapter 1.1 | 0 | yes | +--------------------------+-------------------+---------+ | Nested Chapter 1.2 | 1 | no | +--------------------------+-------------------+---------+ | Chapter 2 | 1 | no | +--------------------------+-------------------+---------+ | Nested Chapter 2.1 | 0 | yes | +--------------------------+-------------------+---------+ | Nested Chapter 2.2 | 1 | no | +--------------------------+-------------------+---------+
Table 50: ChapterFlagHidden Nested Visibility
20.3. Menu Features
-
The menu features are handled like a chapter codec. That means each codec has a type, some private data, and some data in the chapters.
The type of the menu system is defined by the ChapProcessCodecID parameter. For now, only two values are supported: 0 (Matroska Script) and 1 (menu borrowed from the DVD [DVD-Video]). The private data stored in ChapProcessPrivate and ChapProcessData depends on the ChapProcessCodecID value.
The menu system, as well as Chapter Codecs in general, can perform actions on the Matroska Player, such as jumping to another Chapter or Edition, selecting different tracks, and possibly more. The scope of all the possibilities of Chapter Codecs is not covered in this document, as it depends on the Chapter Codec features and its integration in a Matroska Player.
20.4. Physical Types
-
Each level can have different meanings for audio and video. The ORIGINAL_MEDIA_TYPE tag [MatroskaTags] can be used to specify a string for ChapterPhysicalEquiv = 60. Here is the list of possible levels for both audio and video:
+=======+=======================+=============+=====================+ | Value | Audio | Video | Comment | +=======+=======================+=============+=====================+ | 70 | SET / PACKAGE | SET / | the collection of | | | | PACKAGE | different media | +-------+-----------------------+-------------+---------------------+ | 60 | CD / 12" / 10" / 7" / | DVD / VHS | the physical medium | | | TAPE / MINIDISC / DAT | / | like a CD or a DVD | | | | LASERDISC | | +-------+-----------------------+-------------+---------------------+ | 50 | SIDE | SIDE | when the original | | | | | medium (LP/DVD) has | | | | | different sides | +-------+-----------------------+-------------+---------------------+ | 40 | - | LAYER | another physical | | | | | level on DVDs | +-------+-----------------------+-------------+---------------------+ | 30 | SESSION | SESSION | as found on CDs and | | | | | DVDs | +-------+-----------------------+-------------+---------------------+ | 20 | TRACK | - | as found on audio | | | | | CDs | +-------+-----------------------+-------------+---------------------+ | 10 | INDEX | - | the first logical | | | | | level of the side/ | | | | | medium | +-------+-----------------------+-------------+---------------------+
Table 51: ChapterPhysicalEquiv Meaning per Track Type
20.5. Chapter Examples
20.5.1. Example 1: Basic Chaptering
-
In this example, a movie is split in different chapters. It could also just be an audio file (album) in which each track corresponds to a chapter.
* 00000 ms - 05000 ms: Intro
* 05000 ms - 25000 ms: Before the crime
* 25000 ms - 27500 ms: The crime
* 27500 ms - 38000 ms: After the crime
* 38000 ms - 43000 ms: CreditsThis translates to Matroska form, with the EBML tree shown as follows in XML:
<Chapters> <EditionEntry> <EditionUID>16603393396715046047</EditionUID> <ChapterAtom> <ChapterUID>1193046</ChapterUID> <ChapterTimeStart>0</ChapterTimeStart> <ChapterTimeEnd>5000000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Intro</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>2311527</ChapterUID> <ChapterTimeStart>5000000000</ChapterTimeStart> <ChapterTimeEnd>25000000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Before the crime</ChapString> </ChapterDisplay> <ChapterDisplay> <ChapString>Avant le crime</ChapString> <ChapLanguage>fra</ChapLanguage> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>3430008</ChapterUID> <ChapterTimeStart>25000000000</ChapterTimeStart> <ChapterTimeEnd>27500000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>The crime</ChapString> </ChapterDisplay> <ChapterDisplay> <ChapString>Le crime</ChapString> <ChapLanguage>fra</ChapLanguage> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>4548489</ChapterUID> <ChapterTimeStart>27500000000</ChapterTimeStart> <ChapterTimeEnd>38000000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>After the crime</ChapString> </ChapterDisplay> <ChapterDisplay> <ChapString>Apres le crime</ChapString> <ChapLanguage>fra</ChapLanguage> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>5666960</ChapterUID> <ChapterTimeStart>38000000000</ChapterTimeStart> <ChapterTimeEnd>43000000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Credits</ChapString> </ChapterDisplay> <ChapterDisplay> <ChapString>Generique</ChapString> <ChapLanguage>fra</ChapLanguage> </ChapterDisplay> </ChapterAtom> </EditionEntry> </Chapters>
Figure 25: Basic Chapters Example
20.5.2. Example 2: Nested Chapters
-
In this example, an (existing) album is split into different chapters, and one of them contains another splitting.
20.5.2.1. The Micronauts "Bleep To Bleep"
-
* 00:00 - 12:28: Baby wants to Bleep/Rock - 00:00 - 04:38: Baby wants to bleep (pt.1) - 04:38 - 07:12: Baby wants to rock - 07:12 - 10:33: Baby wants to bleep (pt.2) - 10:33 - 12:28: Baby wants to bleep (pt.3) * 12:30 - 19:38: Bleeper_O+2 * 19:40 - 22:20: Baby wants to bleep (pt.4) * 22:22 - 25:18: Bleep to bleep * 25:20 - 33:35: Baby wants to bleep (k) * 33:37 - 44:28: BleeperThis translates to Matroska form, with the EBML tree shown as follows in XML:
<Chapters> <EditionEntry> <EditionUID>1281690858003401414</EditionUID> <ChapterAtom> <ChapterUID>1</ChapterUID> <ChapterTimeStart>0</ChapterTimeStart> <ChapterTimeEnd>748000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to Bleep/Rock</ChapString> </ChapterDisplay> <ChapterAtom> <ChapterUID>2</ChapterUID> <ChapterTimeStart>0</ChapterTimeStart> <ChapterTimeEnd>278000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to bleep (pt.1)</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>3</ChapterUID> <ChapterTimeStart>278000000</ChapterTimeStart> <ChapterTimeEnd>432000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to rock</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>4</ChapterUID> <ChapterTimeStart>432000000</ChapterTimeStart> <ChapterTimeEnd>633000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to bleep (pt.2)</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>5</ChapterUID> <ChapterTimeStart>633000000</ChapterTimeStart> <ChapterTimeEnd>748000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to bleep (pt.3)</ChapString> </ChapterDisplay> </ChapterAtom> </ChapterAtom> <ChapterAtom> <ChapterUID>6</ChapterUID> <ChapterTimeStart>750000000</ChapterTimeStart> <ChapterTimeEnd>1178500000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Bleeper_O+2</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>7</ChapterUID> <ChapterTimeStart>1180500000</ChapterTimeStart> <ChapterTimeEnd>1340000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to bleep (pt.4)</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>8</ChapterUID> <ChapterTimeStart>1342000000</ChapterTimeStart> <ChapterTimeEnd>1518000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Bleep to bleep</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>9</ChapterUID> <ChapterTimeStart>1520000000</ChapterTimeStart> <ChapterTimeEnd>2015000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Baby wants to bleep (k)</ChapString> </ChapterDisplay> </ChapterAtom> <ChapterAtom> <ChapterUID>10</ChapterUID> <ChapterTimeStart>2017000000</ChapterTimeStart> <ChapterTimeEnd>2668000000</ChapterTimeEnd> <ChapterDisplay> <ChapString>Bleeper</ChapString> </ChapterDisplay> </ChapterAtom> </EditionEntry> </Chapters>
Figure 26: Nested Chapters Example
21. Attachments
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Matroska supports storage of related files and data in the Attachments element (a Top-Level Element). Attachments elements can be used to store related cover art, font files, transcripts, reports, error recovery files, pictures, text-based annotations, copies of specifications, or other ancillary files related to the Segment.
Matroska Readers MUST NOT execute files stored as Attachments elements.
21.1. Cover Art
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This section defines a set of guidelines for the storage of cover art in Matroska files. A Matroska Reader MAY use embedded cover art to display a representational still-image depiction of the multimedia contents of the Matroska file.
Only [JPEG] and PNG [RFC2083] image formats SHOULD be used for cover art pictures.
There can be two different covers for a movie/album: a portrait style (e.g., a DVD case) and a landscape style (e.g., a wide banner ad).
There can be two versions of the same cover: the normal cover and the small cover. The dimension of the normal cover SHOULD be 600 pixels on the smallest side (e.g., 960x600 for landscape, 600x800 for portrait, or 600x600 for square). The dimension of the small cover SHOULD be 120 pixels on the smallest side (e.g., 192x120 or 120x160).
Versions of cover art can be differentiated by the filename, which is stored in the FileName element. The default filename of the normal cover in square or portrait mode is cover.(jpg|png). When stored, the normal cover SHOULD be the first Attachments element in storage order. The small cover SHOULD be prefixed with "small_", such as small_cover.(jpg|png). The landscape variant SHOULD be suffixed with "_land", such as cover_land.(jpg|png). The filenames are case- sensitive.
The following table provides examples of file names for cover art in Attachments.
+======================+===================+=================+ | File Name | Image Orientation | Pixel Length of | | | | Smallest Side | +======================+===================+=================+ | cover.jpg | Portrait or | 600 | | | square | | +----------------------+-------------------+-----------------+ | small_cover.png | Portrait or | 120 | | | square | | +----------------------+-------------------+-----------------+ | cover_land.png | Landscape | 600 | +----------------------+-------------------+-----------------+ | small_cover_land.jpg | Landscape | 120 | +----------------------+-------------------+-----------------+
Table 52: Cover Art Filenames
21.2. Font Files
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Font files MAY be added to a Matroska file as Attachments so that the font file may be used to display an associated subtitle track. This allows the presentation of a Matroska file to be consistent in various environments where the needed fonts might not be available on the local system.
Depending on the font format in question, each font file can contain multiple font variants. Each font variant has a name that will be referred to as Font Name from now on. This Font Name can be different from the Attachment's FileName, even when disregarding the extension. In order to select a font for display, a Matroska Player SHOULD consider both the Font Name and the base name of the Attachment's FileName, preferring the former when there are multiple matches.
Subtitle codecs, such as SubStation Alpha (SSA) and Advanced SubStation Alpha (ASS), usually refer to a font by its Font Name, not by its filename. If none of the Attachments are a match for the Font Name, the Matroska Player SHOULD attempt to find a system font whose Font Name matches the one used in the subtitle track.
Since loading fonts temporarily can take a while, a Matroska Player usually loads or installs all the fonts found in attachments so they are ready to be used during playback. Failure to use the font attachment might result in incorrect rendering of the subtitles.
If a selected subtitle track has some AttachmentLink elements, the player MAY restrict its font rendering to use only these fonts.
A Matroska Player SHOULD handle the official font media types from [RFC8081] when the system can handle the type:
* font/sfnt: Generic SFNT Font Type * font/ttf: TrueType Font (TTF) Font Type * font/otf: OpenType Layout (OTF) Font Type * font/collection: Collection Font Type
- font/woff: WOFF 1.0
- font/woff2: WOFF 2.0
Fonts in Matroska existed long before [RFC8081]. A few unofficial media types for fonts were used in existing files. Therefore, it is RECOMMENDED for a Matroska Player to support the following legacy media types for font attachments:
* application/x-truetype-font: TrueType fonts, equivalent to font/ ttf and sometimes font/otf * application/x-font-ttf: TrueType fonts, equivalent to font/ttf * application/vnd.ms-opentype: OpenType Layout fonts, equivalent to font/otf * application/font-sfnt: Generic SFNT Font Type, equivalent to font/ sfnt * application/font-woff: WOFF 1.0, equivalent to font/woffThere may also be some font attachments with the application/octet- stream media type. In that case, the Matroska Player MAY try to guess the font type by checking the file extension of the AttachedFile\FileName string. Common file extensions for fonts are:
* .ttf for TrueType fonts, equivalent to font/ttf * .otf for OpenType Layout fonts, equivalent to font/otf * .ttc for Collection fonts, equivalent to font/collection
The file extension check MUST be case-insensitive.
Matroska Writers SHOULD use a valid font media type from [RFC8081] in the AttachedFile\FileMediaType of the font attachment. They MAY use the media types found in older files when compatibility with older players is necessary.
22. Cues
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The Cues element provides an index of certain Cluster elements to allow for optimized seeking to absolute timestamps within the Segment. The Cues element contains one or many CuePoint elements, each of which MUST reference an absolute timestamp (via the CueTime element), a Track (via the CueTrack element), and a Segment Position (via the CueClusterPosition element). Additional non-mandated elements are part of the CuePoint element, such as CueDuration, CueRelativePosition, CueCodecState, and others that provide any Matroska Reader with additional information to use in the optimization of seeking performance.
22.1. Recommendations
-
The following recommendations are provided to optimize Matroska performance.
- Unless Matroska is used as a live stream, it SHOULD contain a Cues element.
- For each video track, each keyframe SHOULD be referenced by a CuePoint element.
- It is RECOMMENDED to not reference non-keyframes of video tracks in Cues unless it references a Cluster element that contains a CodecState element but no keyframes.
- For each subtitle track present, each subtitle frame SHOULD be referenced by a CuePoint element with a CueDuration element.
- References to audio tracks MAY be skipped in CuePoint elements if a video track is present. When included, the CuePoint elements SHOULD reference audio keyframes once every 500 milliseconds at most.
- If the referenced frame is not stored within the first SimpleBlock or first BlockGroup within its Cluster element, then the CueRelativePosition element SHOULD be written to reference where in the Cluster the reference frame is stored.
- If a CuePoint element references a Cluster element that includes a CodecState element, then that CuePoint element MUST use a CueCodecState element.
- CuePoint elements SHOULD be numerically sorted in storage order by the value of the CueTime element.
23. Matroska Streaming
-
In Matroska, there are two kinds of streaming: file access and livestreaming.
23.1. File Access
-
File access can simply be reading a file located on your computer, but it also includes accessing a file from an HTTP (web) server or Common Internet File System (CIFS) (Windows share) server. These protocols are usually safe from reading errors, and seeking in the stream is possible. However, when a file is stored far away or on a slow server, seeking can be an expensive operation and should be avoided. When followed, the guidelines in Section 25 help reduce the number of seeking operations for regular playback and also have the playback start quickly without needing to read lot of data first (like a Cues element, Attachments element, or SeekHead element).
Matroska, having a small overhead, is well suited for storing music/ videos on file servers without a big impact on the bandwidth used. Matroska does not require the index to be loaded before playing, which allows playback to start very quickly. The index can be loaded only when seeking is requested the first time.
23.2. Livestreaming
-
Livestreaming is the equivalent of television broadcasting on the Internet. There are two families of servers for livestreaming: RTP / Real-Time Streaming Protocol (RTSP) and HTTP. Matroska is not meant to be used over RTP. RTP already has timing and channel mechanisms that would be wasted if doubled in Matroska. Additionally, having the same information at the RTP and Matroska level would be a source of confusion if they do not match. Livestreaming of Matroska over file-like protocols like HTTP, QUIC, etc., is possible.
A live Matroska stream is different from a file because it usually has no known end (only ending when the client disconnects). For this, all bits of the "size" portion of the Segment element MUST be set to 1. Another option is to concatenate Segment elements with known sizes, one after the other. This solution allows a change of codec/resolution between each segment. For example, this allows for a switch between 4:3 and 16:9 in a television program.
When Segment elements are continuous, certain elements (like SeekHead, Cues, Chapters, and Attachments) MUST NOT be used.
It is possible for a Matroska Player to detect that a stream is not seekable. If the stream has neither a SeekHead list nor a Cues list at the beginning of the stream, it SHOULD be considered non-seekable. Even though it is possible to seek forward in the stream, it is NOT RECOMMENDED.
In the context of live radio or web TV, it is possible to "tag" the content while it is playing. The Tags element can be placed between Clusters each time it is necessary. In that case, the new Tags element MUST reset the previously encountered Tags elements and use the new values instead.
24. Tags
24.1. Tags Precedence
-
Tags allow tagging all kinds of Matroska parts with very detailed metadata in multiple languages.
Some Matroska elements also contain their own string value, like the track Name element (Section 5.1.4.1.18) or the ChapString element (Section 5.1.7.1.4.10).
The following Matroska elements can also be defined with tags:
- The track Name element (Section 5.1.4.1.18) corresponds to a tag with the TagTrackUID (Section 5.1.8.1.1.3) set to the given track, a TagName of TITLE (Section 5.1.8.1.2.1), and a TagLanguage (Section 5.1.8.1.2.2) or TagLanguageBCP47 (Section 5.1.8.1.2.3) of "und".
- The ChapString element (Section 5.1.7.1.4.10) corresponds to a tag with the TagChapterUID (Section 5.1.8.1.1.5) set to the same chapter UID, a TagName of TITLE (Section 5.1.8.1.2.1), and a TagLanguage (Section 5.1.8.1.2.2) or TagLanguageBCP47 (Section 5.1.8.1.2.3) matching the ChapLanguage (Section 5.1.7.1.4.11) or ChapLanguageBCP47 (Section 5.1.7.1.4.12), respectively.
* The FileDescription element (Section 5.1.6.1.1) of an attachment corresponds to a tag with the TagAttachmentUID (Section 5.1.8.1.1.6) set to the given attachment, a TagName of TITLE (Section 5.1.8.1.2.1), and a TagLanguage (Section 5.1.8.1.2.2) or TagLanguageBCP47 (Section 5.1.8.1.2.3) of "und".When both values exist in the file, the value found in Tags takes precedence over the value found in the original location of the element. For example, if you have a TrackEntry\Name element and a tag value TITLE for that track in a Matroska Segment, the tag value string SHOULD be used instead of the TrackEntry\Name string to identify the track.
As the Tag element is optional, a lot of Matroska Readers do not handle it and will not use the tags value when it's found. Thus, for maximum compatibility, it's usually better to put the strings in the TrackEntry, ChapterAtom, and Attachments elements and keep the tags matching these values if tags are also used.
24.2. Tag Levels
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Tag elements allow tagging information on multiple levels, with each level having a TargetTypeValue (Section 5.1.8.1.1.1). An element for a given TargetTypeValue also applies to the lower levels denoted by smaller TargetTypeValue values. If an upper value doesn't apply to a level but the actual value to use is not known, an empty TagString (Section 5.1.8.1.2.5) or an empty TagBinary (Section 5.1.8.1.2.6) MUST be used as the tag value for this level.
See [MatroskaTags] for more details on common tag names, types, and descriptions.
25. Implementation Recommendations
25.1. Cluster
-
It is RECOMMENDED that each individual Cluster element contain no more than five seconds or five megabytes of content.
25.2. SeekHead
-
It is RECOMMENDED that the first SeekHead element be followed by a Void element to allow for the SeekHead element to be expanded to cover new Top-Level Elements that could be added to the Matroska file, such as Tags, Chapters, and Attachments elements.
The size of this Void element should be adjusted depending on the Tags, Chapters, and Attachments elements in the Matroska file.
25.3. Optimum Layouts
-
While there can be Top-Level Elements in any order, some orderings of elements are better than others. The following subsections detail optimum layouts for different use cases.
25.3.1. Optimum Layout for a Muxer
-
This is the basic layout muxers should be using for an efficient playback experience:
* SeekHead * Info * Tracks * Chapters * Attachments * Tags * Clusters * Cues
25.3.2. Optimum Layout after Editing Tags
-
When tags from the previous layout need to be extended, they are moved to the end with the extra information. The location where the old tags were located is voided.
* SeekHead * Info * Tracks * Chapters * Attachments * Void * Clusters * Cues * Tags
25.3.3. Optimum Layout with Cues at the Front
-
Cues are usually a big chunk of data referencing a lot of locations in the file. Players that want to seek in the file need to seek to the end of the file to access these locations. It is often better if they are placed early in the file. On the other hand, that means players that don't intend to seek will have to read/skip these data no matter what.
Because the Cues reference locations further in the file, it's often complicated to allocate the proper space for that element before all the locations are known. Therefore, this layout is rarely used:
* SeekHead * Info * Tracks * Chapters * Attachments * Tags * Cues * Clusters
25.3.4. Optimum Layout for Livestreaming
-
In livestreaming (Section 23.2), only a few elements make sense. For example, SeekHead and Cues are useless. All elements other than the Clusters MUST be placed before the Clusters.
* Info * Tracks * Attachments (rare) * Tags * Clusters
26. Security Considerations
-
Matroska inherits security considerations from EBML [RFC8794].
Attacks on a Matroska Reader could include:
- Storage of an arbitrary and potentially executable data within an Attachments element. Matroska Readers that extract or use data from Matroska Attachments SHOULD check that the data adheres to expectations or not use the attachment.
- A Matroska Attachment with an inaccurate media type.
- Damage to the Encryption and Compression fields (Section 14) that would result in bogus binary data interpreted by the decoder.
- Chapter Codecs running unwanted commands on the host system.
The same error handling done for EBML applies to Matroska files. Particular error handling is not covered in this specification, as this is depends on the goal of the Matroska Readers. Matroska Readers decide how to handle the errors whether or not they are recoverable in their code. For example, if the checksum of the \Segment\Tracks is invalid, some could decide to try to read the data anyway, some will just reject the file, and most will not even check it.
Matroska Reader implementations need to be robust against malicious payloads. Those related to denial of service are outlined in Section 2.1 of [RFC4732].
Although rarer, the same may apply to a Matroska Writer. Malicious stream data must not cause the Matroska Writer to misbehave, as this might allow an attacker access to transcoding gateways.
As an audio/video container format, a Matroska file or stream will potentially encapsulate numerous byte streams created with a variety of codecs. Implementers will need to consider the security considerations of these encapsulated formats.
27. IANA Considerations
27.1. Matroska Element IDs Registry
-
IANA has created a new registry called the "Matroska Element IDs" registry.
To register a new Element ID in this registry, one needs an Element ID, an Element Name, a Change Controller, and an optional Reference to a document describing the Element ID.
Element IDs are encoded using the VINT mechanism described in Section 4 of [RFC8794] and can be between one and five octets long. Five-octet Element IDs are possible only if declared in the EBML Header.
Element IDs are described in Section 5 of [RFC8794], with the changes in [Err7189] and [Err7191].
One-octet Matroska Element IDs (range 0x80-0xFE) are to be allocated according to the "RFC Required" policy [RFC8126].
Two-octet Matroska Element IDs (range 0x407F-0x7FFE) are to be allocated according to the "Specification Required" policy [RFC8126].
Two-octet Matroska Element IDs between 0x0100 and 0x407E are not valid for use as an Element ID.
Three-octet (range 0x203FFF-0x3FFFFE) and four-octet Matroska Element IDs (range 0x101FFFFF-0x1FFFFFFE) are to be allocated according to the "First Come First Served" policy [RFC8126].
Three-octet Matroska Element IDs between 0x010000 and 0x203FFE are not valid for use as an Element ID.
Four-octet Matroska Element IDs between 0x01000000 and 0x101FFFFE are not valid for use as an Element ID.
The allowed values in the "Matroska Element IDs" registry are similar to the ones found in the "EBML Element IDs" registry defined in Section 17.1 of [RFC8794].
EBML Element IDs defined for the EBML Header -- as defined in Section 17.1 of [RFC8794] -- MUST NOT be used as Matroska Element IDs.
Given the scarcity of one-octet Element IDs, they should only be created to save space for elements found many times in a file (for example, BlockGroup or Chapters). The four-octet Element IDs are mostly for synchronization of large elements. They should only be used for such high-level elements. Elements that are not expected to be used often should use three-octet Element IDs.
Elements found in Appendix A have an assigned Matroska Element ID for historical reasons. These elements are not in use and SHOULD NOT be reused unless there are no other IDs available with the desired size. Such IDs are marked as "Reclaimed" in the "Matroska Element IDs" registry, as they could be used for other things in the future.
Table 53 shows the initial contents of the "Matroska Element IDs" registry. The Change Controller for the initial entries is the IETF.
+=====================+=============================+==============+ | Element ID| Element Name |Reference | +=====================+=============================+==============+ | 0x80| ChapterDisplay |RFC 9559, | | | |Section | | | |5.1.7.1.4.9 | +---------------------+-----------------------------+--------------+ | 0x83| TrackType |RFC 9559, | | | |Section | | | |5.1.4.1.3 | +---------------------+-----------------------------+--------------+ | 0x85| ChapString |RFC 9559, | | | |Section | | | |5.1.7.1.4.10 | +---------------------+-----------------------------+--------------+ | 0x86| CodecID |RFC 9559, | | | |Section | | | |5.1.4.1.21 | +---------------------+-----------------------------+--------------+ | 0x88| FlagDefault |RFC 9559, | | | |Section | | | |5.1.4.1.5 | +---------------------+-----------------------------+--------------+ | 0x8E| Slices |Reclaimed (RFC| | | |9559, | | | |Appendix A.5) | +---------------------+-----------------------------+--------------+ | 0x91| ChapterTimeStart |RFC 9559, | | | |Section | | | |5.1.7.1.4.3 | +---------------------+-----------------------------+--------------+ | 0x92| ChapterTimeEnd |RFC 9559, | | | |Section | | | |5.1.7.1.4.4 | +---------------------+-----------------------------+--------------+ | 0x96| CueRefTime |RFC 9559, | | | |Section | | | |5.1.5.1.2.8 | +---------------------+-----------------------------+--------------+ | 0x97| CueRefCluster |Reclaimed (RFC| | | |9559, | | | |Appendix A.37)| +---------------------+-----------------------------+--------------+ | 0x98| ChapterFlagHidden |RFC 9559, | | | |Section | | | |5.1.7.1.4.5 | +---------------------+-----------------------------+--------------+ | 0x9A| FlagInterlaced |RFC 9559, | | | |Section | | | |5.1.4.1.28.1 | +---------------------+-----------------------------+--------------+ | 0x9B| BlockDuration |RFC 9559, | | | |Section | | | |5.1.3.5.3 | +---------------------+-----------------------------+--------------+ | 0x9C| FlagLacing |RFC 9559, | | | |Section | | | |5.1.4.1.12 | +---------------------+-----------------------------+--------------+ | 0x9D| FieldOrder |RFC 9559, | | | |Section | | | |5.1.4.1.28.2 | +---------------------+-----------------------------+--------------+ | 0x9F| Channels |RFC 9559, | | | |Section | | | |5.1.4.1.29.3 | +---------------------+-----------------------------+--------------+ | 0xA0| BlockGroup |RFC 9559, | | | |Section | | | |5.1.3.5 | +---------------------+-----------------------------+--------------+ | 0xA1| Block |RFC 9559, | | | |Section | | | |5.1.3.5.1 | +---------------------+-----------------------------+--------------+ | 0xA2| BlockVirtual |Reclaimed (RFC| | | |9559, | | | |Appendix A.3) | +---------------------+-----------------------------+--------------+ | 0xA3| SimpleBlock |RFC 9559, | | | |Section | | | |5.1.3.4 | +---------------------+-----------------------------+--------------+ | 0xA4| CodecState |RFC 9559, | | | |Section | | | |5.1.3.5.6 | +---------------------+-----------------------------+--------------+ | 0xA5| BlockAdditional |RFC 9559, | | | |Section | | | |5.1.3.5.2.2 | +---------------------+-----------------------------+--------------+ | 0xA6| BlockMore |RFC 9559, | | | |Section | | | |5.1.3.5.2.1 | +---------------------+-----------------------------+--------------+ | 0xA7| Position |RFC 9559, | | | |Section | | | |5.1.3.2 | +---------------------+-----------------------------+--------------+ | 0xAA| CodecDecodeAll |Reclaimed (RFC| | | |9559, | | | |Appendix A.22)| +---------------------+-----------------------------+--------------+ | 0xAB| PrevSize |RFC 9559, | | | |Section | | | |5.1.3.3 | +---------------------+-----------------------------+--------------+ | 0xAE| TrackEntry |RFC 9559, | | | |Section | | | |5.1.4.1 | +---------------------+-----------------------------+--------------+ | 0xAF| EncryptedBlock |Reclaimed (RFC| | | |9559, | | | |Appendix A.15)| +---------------------+-----------------------------+--------------+ | 0xB0| PixelWidth |RFC 9559, | | | |Section | | | |5.1.4.1.28.6 | +---------------------+-----------------------------+--------------+ | 0xB2| CueDuration |RFC 9559, | | | |Section | | | |5.1.5.1.2.4 | +---------------------+-----------------------------+--------------+ | 0xB3| CueTime |RFC 9559, | | | |Section | | | |5.1.5.1.1 | +---------------------+-----------------------------+--------------+ | 0xB5| SamplingFrequency |RFC 9559, | | | |Section | | | |5.1.4.1.29.1 | +---------------------+-----------------------------+--------------+ | 0xB6| ChapterAtom |RFC 9559, | | | |Section | | | |5.1.7.1.4 | +---------------------+-----------------------------+--------------+ | 0xB7| CueTrackPositions |RFC 9559, | | | |Section | | | |5.1.5.1.2 | +---------------------+-----------------------------+--------------+ | 0xB9| FlagEnabled |RFC 9559, | | | |Section | | | |5.1.4.1.4 | +---------------------+-----------------------------+--------------+ | 0xBA| PixelHeight |RFC 9559, | | | |Section | | | |5.1.4.1.28.7 | +---------------------+-----------------------------+--------------+ | 0xBB| CuePoint |RFC 9559, | | | |Section | | | |5.1.5.1 | +---------------------+-----------------------------+--------------+ | 0xC0| TrickTrackUID |Reclaimed (RFC| | | |9559, | | | |Appendix A.28)| +---------------------+-----------------------------+--------------+ | 0xC1| TrickTrackSegmentUID |Reclaimed (RFC| | | |9559, | | | |Appendix A.29)| +---------------------+-----------------------------+--------------+ | 0xC4| TrickMasterTrackSegmentUID |Reclaimed (RFC| | | |9559, | | | |Appendix A.32)| +---------------------+-----------------------------+--------------+ | 0xC6| TrickTrackFlag |Reclaimed (RFC| | | |9559, | | | |Appendix A.30)| +---------------------+-----------------------------+--------------+ | 0xC7| TrickMasterTrackUID |Reclaimed (RFC| | | |9559, | | | |Appendix A.31)| +---------------------+-----------------------------+--------------+ | 0xC8| ReferenceFrame |Reclaimed (RFC| | | |9559, | | | |Appendix A.12)| +---------------------+-----------------------------+--------------+ | 0xC9| ReferenceOffset |Reclaimed (RFC| | | |9559, | | | |Appendix A.13)| +---------------------+-----------------------------+--------------+ | 0xCA| ReferenceTimestamp |Reclaimed (RFC| | | |9559, | | | |Appendix A.14)| +---------------------+-----------------------------+--------------+ | 0xCB| BlockAdditionID |Reclaimed (RFC| | | |9559, | | | |Appendix A.9) | +---------------------+-----------------------------+--------------+ | 0xCC| LaceNumber |Reclaimed (RFC| | | |9559, | | | |Appendix A.7) | +---------------------+-----------------------------+--------------+ | 0xCD| FrameNumber |Reclaimed (RFC| | | |9559, | | | |Appendix A.8) | +---------------------+-----------------------------+--------------+ | 0xCE| Delay |Reclaimed (RFC| | | |9559, | | | |Appendix A.10)| +---------------------+-----------------------------+--------------+ | 0xCF| SliceDuration |Reclaimed (RFC| | | |9559, | | | |Appendix A.11)| +---------------------+-----------------------------+--------------+ | 0xD7| TrackNumber |RFC 9559, | | | |Section | | | |5.1.4.1.1 | +---------------------+-----------------------------+--------------+ | 0xDB| CueReference |RFC 9559, | | | |Section | | | |5.1.5.1.2.7 | +---------------------+-----------------------------+--------------+ | 0xE0| Video |RFC 9559, | | | |Section | | | |5.1.4.1.28 | +---------------------+-----------------------------+--------------+ | 0xE1| Audio |RFC 9559, | | | |Section | | | |5.1.4.1.29 | +---------------------+-----------------------------+--------------+ | 0xE2| TrackOperation |RFC 9559, | | | |Section | | | |5.1.4.1.30 | +---------------------+-----------------------------+--------------+ | 0xE3| TrackCombinePlanes |RFC 9559, | | | |Section | | | |5.1.4.1.30.1 | +---------------------+-----------------------------+--------------+ | 0xE4| TrackPlane |RFC 9559, | | | |Section | | | |5.1.4.1.30.2 | +---------------------+-----------------------------+--------------+ | 0xE5| TrackPlaneUID |RFC 9559, | | | |Section | | | |5.1.4.1.30.3 | +---------------------+-----------------------------+--------------+ | 0xE6| TrackPlaneType |RFC 9559, | | | |Section | | | |5.1.4.1.30.4 | +---------------------+-----------------------------+--------------+ | 0xE7| Timestamp |RFC 9559, | | | |Section | | | |5.1.3.1 | +---------------------+-----------------------------+--------------+ | 0xE8| TimeSlice |Reclaimed (RFC| | | |9559, | | | |Appendix A.6) | +---------------------+-----------------------------+--------------+ | 0xE9| TrackJoinBlocks |RFC 9559, | | | |Section | | | |5.1.4.1.30.5 | +---------------------+-----------------------------+--------------+ | 0xEA| CueCodecState |RFC 9559, | | | |Section | | | |5.1.5.1.2.6 | +---------------------+-----------------------------+--------------+ | 0xEB| CueRefCodecState |Reclaimed (RFC| | | |9559, | | | |Appendix A.39)| +---------------------+-----------------------------+--------------+ | 0xED| TrackJoinUID |RFC 9559, | | | |Section | | | |5.1.4.1.30.6 | +---------------------+-----------------------------+--------------+ | 0xEE| BlockAddID |RFC 9559, | | | |Section | | | |5.1.3.5.2.3 | +---------------------+-----------------------------+--------------+ | 0xF0| CueRelativePosition |RFC 9559, | | | |Section | | | |5.1.5.1.2.3 | +---------------------+-----------------------------+--------------+ | 0xF1| CueClusterPosition |RFC 9559, | | | |Section | | | |5.1.5.1.2.2 | +---------------------+-----------------------------+--------------+ | 0xF7| CueTrack |RFC 9559, | | | |Section | | | |5.1.5.1.2.1 | +---------------------+-----------------------------+--------------+ | 0xFA| ReferencePriority |RFC 9559, | | | |Section | | | |5.1.3.5.4 | +---------------------+-----------------------------+--------------+ | 0xFB| ReferenceBlock |RFC 9559, | | | |Section | | | |5.1.3.5.5 | +---------------------+-----------------------------+--------------+ | 0xFD| ReferenceVirtual |Reclaimed (RFC| | | |9559, | | | |Appendix A.4) | +---------------------+-----------------------------+--------------+ | 0xFF| Reserved |RFC 9559 | +---------------------+-----------------------------+--------------+ | 0x0100-0x407E| Not valid for use as an |RFC 9559, | | | Element ID |Section 27.1 | +---------------------+-----------------------------+--------------+ | 0x41A4| BlockAddIDName |RFC 9559, | | | |Section | | | |5.1.4.1.17.2 | +---------------------+-----------------------------+--------------+ | 0x41E4| BlockAdditionMapping |RFC 9559, | | | |Section | | | |5.1.4.1.17 | +---------------------+-----------------------------+--------------+ | 0x41E7| BlockAddIDType |RFC 9559, | | | |Section | | | |5.1.4.1.17.3 | +---------------------+-----------------------------+--------------+ | 0x41ED| BlockAddIDExtraData |RFC 9559, | | | |Section | | | |5.1.4.1.17.4 | +---------------------+-----------------------------+--------------+ | 0x41F0| BlockAddIDValue |RFC 9559, | | | |Section | | | |5.1.4.1.17.1 | +---------------------+-----------------------------+--------------+ | 0x4254| ContentCompAlgo |RFC 9559, | | | |Section | | | |5.1.4.1.31.6 | +---------------------+-----------------------------+--------------+ | 0x4255| ContentCompSettings |RFC 9559, | | | |Section | | | |5.1.4.1.31.7 | +---------------------+-----------------------------+--------------+ | 0x437C| ChapLanguage |RFC 9559, | | | |Section | | | |5.1.7.1.4.11 | +---------------------+-----------------------------+--------------+ | 0x437D| ChapLanguageBCP47 |RFC 9559, | | | |Section | | | |5.1.7.1.4.12 | +---------------------+-----------------------------+--------------+ | 0x437E| ChapCountry |RFC 9559, | | | |Section | | | |5.1.7.1.4.13 | +---------------------+-----------------------------+--------------+ | 0x4444| SegmentFamily |RFC 9559, | | | |Section | | | |5.1.2.7 | +---------------------+-----------------------------+--------------+ | 0x4461| DateUTC |RFC 9559, | | | |Section | | | |5.1.2.11 | +---------------------+-----------------------------+--------------+ | 0x447A| TagLanguage |RFC 9559, | | | |Section | | | |5.1.8.1.2.2 | +---------------------+-----------------------------+--------------+ | 0x447B| TagLanguageBCP47 |RFC 9559, | | | |Section | | | |5.1.8.1.2.3 | +---------------------+-----------------------------+--------------+ | 0x4484| TagDefault |RFC 9559, | | | |Section | | | |5.1.8.1.2.4 | +---------------------+-----------------------------+--------------+ | 0x4485| TagBinary |RFC 9559, | | | |Section | | | |5.1.8.1.2.6 | +---------------------+-----------------------------+--------------+ | 0x4487| TagString |RFC 9559, | | | |Section | | | |5.1.8.1.2.5 | +---------------------+-----------------------------+--------------+ | 0x4489| Duration |RFC 9559, | | | |Section | | | |5.1.2.10 | +---------------------+-----------------------------+--------------+ | 0x44B4| TagDefaultBogus |Reclaimed (RFC| | | |9559, | | | |Appendix A.43)| +---------------------+-----------------------------+--------------+ | 0x450D| ChapProcessPrivate |RFC 9559, | | | |Section | | | |5.1.7.1.4.16 | +---------------------+-----------------------------+--------------+ | 0x45A3| TagName |RFC 9559, | | | |Section | | | |5.1.8.1.2.1 | +---------------------+-----------------------------+--------------+ | 0x45B9| EditionEntry |RFC 9559, | | | |Section | | | |5.1.7.1 | +---------------------+-----------------------------+--------------+ | 0x45BC| EditionUID |RFC 9559, | | | |Section | | | |5.1.7.1.1 | +---------------------+-----------------------------+--------------+ | 0x45DB| EditionFlagDefault |RFC 9559, | | | |Section | | | |5.1.7.1.2 | +---------------------+-----------------------------+--------------+ | 0x45DD| EditionFlagOrdered |RFC 9559, | | | |Section | | | |5.1.7.1.3 | +---------------------+-----------------------------+--------------+ | 0x465C| FileData |RFC 9559, | | | |Section | | | |5.1.6.1.4 | +---------------------+-----------------------------+--------------+ | 0x4660| FileMediaType |RFC 9559, | | | |Section | | | |5.1.6.1.3 | +---------------------+-----------------------------+--------------+ | 0x4661| FileUsedStartTime |Reclaimed (RFC| | | |9559, | | | |Appendix A.41)| +---------------------+-----------------------------+--------------+ | 0x4662| FileUsedEndTime |Reclaimed (RFC| | | |9559, | | | |Appendix A.42)| +---------------------+-----------------------------+--------------+ | 0x466E| FileName |RFC 9559, | | | |Section | | | |5.1.6.1.2 | +---------------------+-----------------------------+--------------+ | 0x4675| FileReferral |Reclaimed (RFC| | | |9559, | | | |Appendix A.40)| +---------------------+-----------------------------+--------------+ | 0x467E| FileDescription |RFC 9559, | | | |Section | | | |5.1.6.1.1 | +---------------------+-----------------------------+--------------+ | 0x46AE| FileUID |RFC 9559, | | | |Section | | | |5.1.6.1.5 | +---------------------+-----------------------------+--------------+ | 0x47E1| ContentEncAlgo |RFC 9559, | | | |Section | | | |5.1.4.1.31.9 | +---------------------+-----------------------------+--------------+ | 0x47E2| ContentEncKeyID |RFC 9559, | | | |Section | | | |5.1.4.1.31.10 | +---------------------+-----------------------------+--------------+ | 0x47E3| ContentSignature |Reclaimed (RFC| | | |9559, | | | |Appendix A.33)| +---------------------+-----------------------------+--------------+ | 0x47E4| ContentSigKeyID |Reclaimed (RFC| | | |9559, | | | |Appendix A.34)| +---------------------+-----------------------------+--------------+ | 0x47E5| ContentSigAlgo |Reclaimed (RFC| | | |9559, | | | |Appendix A.35)| +---------------------+-----------------------------+--------------+ | 0x47E6| ContentSigHashAlgo |Reclaimed (RFC| | | |9559, | | | |Appendix A.36)| +---------------------+-----------------------------+--------------+ | 0x47E7| ContentEncAESSettings |RFC 9559, | | | |Section | | | |5.1.4.1.31.11 | +---------------------+-----------------------------+--------------+ | 0x47E8| AESSettingsCipherMode |RFC 9559, | | | |Section | | | |5.1.4.1.31.12 | +---------------------+-----------------------------+--------------+ | 0x4D80| MuxingApp |RFC 9559, | | | |Section | | | |5.1.2.13 | +---------------------+-----------------------------+--------------+ | 0x4DBB| Seek |RFC 9559, | | | |Section | | | |5.1.1.1 | +---------------------+-----------------------------+--------------+ | 0x5031| ContentEncodingOrder |RFC 9559, | | | |Section | | | |5.1.4.1.31.2 | +---------------------+-----------------------------+--------------+ | 0x5032| ContentEncodingScope |RFC 9559, | | | |Section | | | |5.1.4.1.31.3 | +---------------------+-----------------------------+--------------+ | 0x5033| ContentEncodingType |RFC 9559, | | | |Section | | | |5.1.4.1.31.4 | +---------------------+-----------------------------+--------------+ | 0x5034| ContentCompression |RFC 9559, | | | |Section | | | |5.1.4.1.31.5 | +---------------------+-----------------------------+--------------+ | 0x5035| ContentEncryption |RFC 9559, | | | |Section | | | |5.1.4.1.31.8 | +---------------------+-----------------------------+--------------+ | 0x535F| CueRefNumber |Reclaimed (RFC| | | |9559, | | | |Appendix A.38)| +---------------------+-----------------------------+--------------+ | 0x536E| Name |RFC 9559, | | | |Section | | | |5.1.4.1.18 | +---------------------+-----------------------------+--------------+ | 0x5378| CueBlockNumber |RFC 9559, | | | |Section | | | |5.1.5.1.2.5 | +---------------------+-----------------------------+--------------+ | 0x537F| TrackOffset |Reclaimed (RFC| | | |9559, | | | |Appendix A.18)| +---------------------+-----------------------------+--------------+ | 0x53AB| SeekID |RFC 9559, | | | |Section | | | |5.1.1.1.1 | +---------------------+-----------------------------+--------------+ | 0x53AC| SeekPosition |RFC 9559, | | | |Section | | | |5.1.1.1.2 | +---------------------+-----------------------------+--------------+ | 0x53B8| StereoMode |RFC 9559, | | | |Section | | | |5.1.4.1.28.3 | +---------------------+-----------------------------+--------------+ | 0x53B9| OldStereoMode |RFC 9559, | | | |Section | | | |5.1.4.1.28.5 | +---------------------+-----------------------------+--------------+ | 0x53C0| AlphaMode |RFC 9559, | | | |Section | | | |5.1.4.1.28.4 | +---------------------+-----------------------------+--------------+ | 0x54AA| PixelCropBottom |RFC 9559, | | | |Section | | | |5.1.4.1.28.8 | +---------------------+-----------------------------+--------------+ | 0x54B0| DisplayWidth |RFC 9559, | | | |Section | | | |5.1.4.1.28.12 | +---------------------+-----------------------------+--------------+ | 0x54B2| DisplayUnit |RFC 9559, | | | |Section | | | |5.1.4.1.28.14 | +---------------------+-----------------------------+--------------+ | 0x54B3| AspectRatioType |Reclaimed (RFC| | | |9559, | | | |Appendix A.24)| +---------------------+-----------------------------+--------------+ | 0x54BA| DisplayHeight |RFC 9559, | | | |Section | | | |5.1.4.1.28.13 | +---------------------+-----------------------------+--------------+ | 0x54BB| PixelCropTop |RFC 9559, | | | |Section | | | |5.1.4.1.28.9 | +---------------------+-----------------------------+--------------+ | 0x54CC| PixelCropLeft |RFC 9559, | | | |Section | | | |5.1.4.1.28.10 | +---------------------+-----------------------------+--------------+ | 0x54DD| PixelCropRight |RFC 9559, | | | |Section | | | |5.1.4.1.28.11 | +---------------------+-----------------------------+--------------+ | 0x55AA| FlagForced |RFC 9559, | | | |Section | | | |5.1.4.1.6 | +---------------------+-----------------------------+--------------+ | 0x55AB| FlagHearingImpaired |RFC 9559, | | | |Section | | | |5.1.4.1.7 | +---------------------+-----------------------------+--------------+ | 0x55AC| FlagVisualImpaired |RFC 9559, | | | |Section | | | |5.1.4.1.8 | +---------------------+-----------------------------+--------------+ | 0x55AD| FlagTextDescriptions |RFC 9559, | | | |Section | | | |5.1.4.1.9 | +---------------------+-----------------------------+--------------+ | 0x55AE| FlagOriginal |RFC 9559, | | | |Section | | | |5.1.4.1.10 | +---------------------+-----------------------------+--------------+ | 0x55AF| FlagCommentary |RFC 9559, | | | |Section | | | |5.1.4.1.11 | +---------------------+-----------------------------+--------------+ | 0x55B0| Colour |RFC 9559, | | | |Section | | | |5.1.4.1.28.16 | +---------------------+-----------------------------+--------------+ | 0x55B1| MatrixCoefficients |RFC 9559, | | | |Section | | | |5.1.4.1.28.17 | +---------------------+-----------------------------+--------------+ | 0x55B2| BitsPerChannel |RFC 9559, | | | |Section | | | |5.1.4.1.28.18 | +---------------------+-----------------------------+--------------+ | 0x55B3| ChromaSubsamplingHorz |RFC 9559, | | | |Section | | | |5.1.4.1.28.19 | +---------------------+-----------------------------+--------------+ | 0x55B4| ChromaSubsamplingVert |RFC 9559, | | | |Section | | | |5.1.4.1.28.20 | +---------------------+-----------------------------+--------------+ | 0x55B5| CbSubsamplingHorz |RFC 9559, | | | |Section | | | |5.1.4.1.28.21 | +---------------------+-----------------------------+--------------+ | 0x55B6| CbSubsamplingVert |RFC 9559, | | | |Section | | | |5.1.4.1.28.22 | +---------------------+-----------------------------+--------------+ | 0x55B7| ChromaSitingHorz |RFC 9559, | | | |Section | | | |5.1.4.1.28.23 | +---------------------+-----------------------------+--------------+ | 0x55B8| ChromaSitingVert |RFC 9559, | | | |Section | | | |5.1.4.1.28.24 | +---------------------+-----------------------------+--------------+ | 0x55B9| Range |RFC 9559, | | | |Section | | | |5.1.4.1.28.25 | +---------------------+-----------------------------+--------------+ | 0x55BA| TransferCharacteristics |RFC 9559, | | | |Section | | | |5.1.4.1.28.26 | +---------------------+-----------------------------+--------------+ | 0x55BB| Primaries |RFC 9559, | | | |Section | | | |5.1.4.1.28.27 | +---------------------+-----------------------------+--------------+ | 0x55BC| MaxCLL |RFC 9559, | | | |Section | | | |5.1.4.1.28.28 | +---------------------+-----------------------------+--------------+ | 0x55BD| MaxFALL |RFC 9559, | | | |Section | | | |5.1.4.1.28.29 | +---------------------+-----------------------------+--------------+ | 0x55D0| MasteringMetadata |RFC 9559, | | | |Section | | | |5.1.4.1.28.30 | +---------------------+-----------------------------+--------------+ | 0x55D1| PrimaryRChromaticityX |RFC 9559, | | | |Section | | | |5.1.4.1.28.31 | +---------------------+-----------------------------+--------------+ | 0x55D2| PrimaryRChromaticityY |RFC 9559, | | | |Section | | | |5.1.4.1.28.32 | +---------------------+-----------------------------+--------------+ | 0x55D3| PrimaryGChromaticityX |RFC 9559, | | | |Section | | | |5.1.4.1.28.33 | +---------------------+-----------------------------+--------------+ | 0x55D4| PrimaryGChromaticityY |RFC 9559, | | | |Section | | | |5.1.4.1.28.34 | +---------------------+-----------------------------+--------------+ | 0x55D5| PrimaryBChromaticityX |RFC 9559, | | | |Section | | | |5.1.4.1.28.35 | +---------------------+-----------------------------+--------------+ | 0x55D6| PrimaryBChromaticityY |RFC 9559, | | | |Section | | | |5.1.4.1.28.36 | +---------------------+-----------------------------+--------------+ | 0x55D7| WhitePointChromaticityX |RFC 9559, | | | |Section | | | |5.1.4.1.28.37 | +---------------------+-----------------------------+--------------+ | 0x55D8| WhitePointChromaticityY |RFC 9559, | | | |Section | | | |5.1.4.1.28.38 | +---------------------+-----------------------------+--------------+ | 0x55D9| LuminanceMax |RFC 9559, | | | |Section | | | |5.1.4.1.28.39 | +---------------------+-----------------------------+--------------+ | 0x55DA| LuminanceMin |RFC 9559, | | | |Section | | | |5.1.4.1.28.40 | +---------------------+-----------------------------+--------------+ | 0x55EE| MaxBlockAdditionID |RFC 9559, | | | |Section | | | |5.1.4.1.16 | +---------------------+-----------------------------+--------------+ | 0x5654| ChapterStringUID |RFC 9559, | | | |Section | | | |5.1.7.1.4.2 | +---------------------+-----------------------------+--------------+ | 0x56AA| CodecDelay |RFC 9559, | | | |Section | | | |5.1.4.1.25 | +---------------------+-----------------------------+--------------+ | 0x56BB| SeekPreRoll |RFC 9559, | | | |Section | | | |5.1.4.1.26 | +---------------------+-----------------------------+--------------+ | 0x5741| WritingApp |RFC 9559, | | | |Section | | | |5.1.2.14 | +---------------------+-----------------------------+--------------+ | 0x5854| SilentTracks |Reclaimed (RFC| | | |9559, | | | |Appendix A.1) | +---------------------+-----------------------------+--------------+ | 0x58D7| SilentTrackNumber |Reclaimed (RFC| | | |9559, | | | |Appendix A.2) | +---------------------+-----------------------------+--------------+ | 0x61A7| AttachedFile |RFC 9559, | | | |Section | | | |5.1.6.1 | +---------------------+-----------------------------+--------------+ | 0x6240| ContentEncoding |RFC 9559, | | | |Section | | | |5.1.4.1.31.1 | +---------------------+-----------------------------+--------------+ | 0x6264| BitDepth |RFC 9559, | | | |Section | | | |5.1.4.1.29.4 | +---------------------+-----------------------------+--------------+ | 0x63A2| CodecPrivate |RFC 9559, | | | |Section | | | |5.1.4.1.22 | +---------------------+-----------------------------+--------------+ | 0x63C0| Targets |RFC 9559, | | | |Section | | | |5.1.8.1.1 | +---------------------+-----------------------------+--------------+ | 0x63C3| ChapterPhysicalEquiv |RFC 9559, | | | |Section | | | |5.1.7.1.4.8 | +---------------------+-----------------------------+--------------+ | 0x63C4| TagChapterUID |RFC 9559, | | | |Section | | | |5.1.8.1.1.5 | +---------------------+-----------------------------+--------------+ | 0x63C5| TagTrackUID |RFC 9559, | | | |Section | | | |5.1.8.1.1.3 | +---------------------+-----------------------------+--------------+ | 0x63C6| TagAttachmentUID |RFC 9559, | | | |Section | | | |5.1.8.1.1.6 | +---------------------+-----------------------------+--------------+ | 0x63C9| TagEditionUID |RFC 9559, | | | |Section | | | |5.1.8.1.1.4 | +---------------------+-----------------------------+--------------+ | 0x63CA| TargetType |RFC 9559, | | | |Section | | | |5.1.8.1.1.2 | +---------------------+-----------------------------+--------------+ | 0x6624| TrackTranslate |RFC 9559, | | | |Section | | | |5.1.4.1.27 | +---------------------+-----------------------------+--------------+ | 0x66A5| TrackTranslateTrackID |RFC 9559, | | | |Section | | | |5.1.4.1.27.1 | +---------------------+-----------------------------+--------------+ | 0x66BF| TrackTranslateCodec |RFC 9559, | | | |Section | | | |5.1.4.1.27.2 | +---------------------+-----------------------------+--------------+ | 0x66FC| TrackTranslateEditionUID |RFC 9559, | | | |Section | | | |5.1.4.1.27.3 | +---------------------+-----------------------------+--------------+ | 0x67C8| SimpleTag |RFC 9559, | | | |Section | | | |5.1.8.1.2 | +---------------------+-----------------------------+--------------+ | 0x68CA| TargetTypeValue |RFC 9559, | | | |Section | | | |5.1.8.1.1.1 | +---------------------+-----------------------------+--------------+ | 0x6911| ChapProcessCommand |RFC 9559, | | | |Section | | | |5.1.7.1.4.17 | +---------------------+-----------------------------+--------------+ | 0x6922| ChapProcessTime |RFC 9559, | | | |Section | | | |5.1.7.1.4.18 | +---------------------+-----------------------------+--------------+ | 0x6924| ChapterTranslate |RFC 9559, | | | |Section | | | |5.1.2.8 | +---------------------+-----------------------------+--------------+ | 0x6933| ChapProcessData |RFC 9559, | | | |Section | | | |5.1.7.1.4.19 | +---------------------+-----------------------------+--------------+ | 0x6944| ChapProcess |RFC 9559, | | | |Section | | | |5.1.7.1.4.14 | +---------------------+-----------------------------+--------------+ | 0x6955| ChapProcessCodecID |RFC 9559, | | | |Section | | | |5.1.7.1.4.15 | +---------------------+-----------------------------+--------------+ | 0x69A5| ChapterTranslateID |RFC 9559, | | | |Section | | | |5.1.2.8.1 | +---------------------+-----------------------------+--------------+ | 0x69BF| ChapterTranslateCodec |RFC 9559, | | | |Section | | | |5.1.2.8.2 | +---------------------+-----------------------------+--------------+ | 0x69FC| ChapterTranslateEditionUID |RFC 9559, | | | |Section | | | |5.1.2.8.3 | +---------------------+-----------------------------+--------------+ | 0x6D80| ContentEncodings |RFC 9559, | | | |Section | | | |5.1.4.1.31 | +---------------------+-----------------------------+--------------+ | 0x6DE7| MinCache |Reclaimed (RFC| | | |9559, | | | |Appendix A.16)| +---------------------+-----------------------------+--------------+ | 0x6DF8| MaxCache |Reclaimed (RFC| | | |9559, | | | |Appendix A.17)| +---------------------+-----------------------------+--------------+ | 0x6E67| ChapterSegmentUUID |RFC 9559, | | | |Section | | | |5.1.7.1.4.6 | +---------------------+-----------------------------+--------------+ | 0x6EBC| ChapterSegmentEditionUID |RFC 9559, | | | |Section | | | |5.1.7.1.4.7 | +---------------------+-----------------------------+--------------+ | 0x6FAB| TrackOverlay |Reclaimed (RFC| | | |9559, | | | |Appendix A.23)| +---------------------+-----------------------------+--------------+ | 0x7373| Tag |RFC 9559, | | | |Section | | | |5.1.8.1 | +---------------------+-----------------------------+--------------+ | 0x7384| SegmentFilename |RFC 9559, | | | |Section | | | |5.1.2.2 | +---------------------+-----------------------------+--------------+ | 0x73A4| SegmentUUID |RFC 9559, | | | |Section | | | |5.1.2.1 | +---------------------+-----------------------------+--------------+ | 0x73C4| ChapterUID |RFC 9559, | | | |Section | | | |5.1.7.1.4.1 | +---------------------+-----------------------------+--------------+ | 0x73C5| TrackUID |RFC 9559, | | | |Section | | | |5.1.4.1.2 | +---------------------+-----------------------------+--------------+ | 0x7446| AttachmentLink |RFC 9559, | | | |Section | | | |5.1.4.1.24 | +---------------------+-----------------------------+--------------+ | 0x75A1| BlockAdditions |RFC 9559, | | | |Section | | | |5.1.3.5.2 | +---------------------+-----------------------------+--------------+ | 0x75A2| DiscardPadding |RFC 9559, | | | |Section | | | |5.1.3.5.7 | +---------------------+-----------------------------+--------------+ | 0x7670| Projection |RFC 9559, | | | |Section | | | |5.1.4.1.28.41 | +---------------------+-----------------------------+--------------+ | 0x7671| ProjectionType |RFC 9559, | | | |Section | | | |5.1.4.1.28.42 | +---------------------+-----------------------------+--------------+ | 0x7672| ProjectionPrivate |RFC 9559, | | | |Section | | | |5.1.4.1.28.43 | +---------------------+-----------------------------+--------------+ | 0x7673| ProjectionPoseYaw |RFC 9559, | | | |Section | | | |5.1.4.1.28.44 | +---------------------+-----------------------------+--------------+ | 0x7674| ProjectionPosePitch |RFC 9559, | | | |Section | | | |5.1.4.1.28.45 | +---------------------+-----------------------------+--------------+ | 0x7675| ProjectionPoseRoll |RFC 9559, | | | |Section | | | |5.1.4.1.28.46 | +---------------------+-----------------------------+--------------+ | 0x78B5| OutputSamplingFrequency |RFC 9559, | | | |Section | | | |5.1.4.1.29.2 | +---------------------+-----------------------------+--------------+ | 0x7BA9| Title |RFC 9559, | | | |Section | | | |5.1.2.12 | +---------------------+-----------------------------+--------------+ | 0x7D7B| ChannelPositions |Reclaimed (RFC| | | |9559, | | | |Appendix A.27)| +---------------------+-----------------------------+--------------+ | 0x7FFF| Reserved |RFC 9559 | +---------------------+-----------------------------+--------------+ | 0x010000-0x203FFE| Not valid for use as an |RFC 9559, | | | Element ID |Section 27.1 | +---------------------+-----------------------------+--------------+ | 0x22B59C| Language |RFC 9559, | | | |Section | | | |5.1.4.1.19 | +---------------------+-----------------------------+--------------+ | 0x22B59D| LanguageBCP47 |RFC 9559, | | | |Section | | | |5.1.4.1.20 | +---------------------+-----------------------------+--------------+ | 0x23314F| TrackTimestampScale |RFC 9559, | | | |Section | | | |5.1.4.1.15 | +---------------------+-----------------------------+--------------+ | 0x234E7A| DefaultDecodedFieldDuration |RFC 9559, | | | |Section | | | |5.1.4.1.14 | +---------------------+-----------------------------+--------------+ | 0x2383E3| FrameRate |Reclaimed (RFC| | | |9559, | | | |Appendix A.26)| +---------------------+-----------------------------+--------------+ | 0x23E383| DefaultDuration |RFC 9559, | | | |Section | | | |5.1.4.1.13 | +---------------------+-----------------------------+--------------+ | 0x258688| CodecName |RFC 9559, | | | |Section | | | |5.1.4.1.23 | +---------------------+-----------------------------+--------------+ | 0x26B240| CodecDownloadURL |Reclaimed (RFC| | | |9559, | | | |Appendix A.21)| +---------------------+-----------------------------+--------------+ | 0x2AD7B1| TimestampScale |RFC 9559, | | | |Section | | | |5.1.2.9 | +---------------------+-----------------------------+--------------+ | 0x2EB524| UncompressedFourCC |RFC 9559, | | | |Section | | | |5.1.4.1.28.15 | +---------------------+-----------------------------+--------------+ | 0x2FB523| GammaValue |Reclaimed (RFC| | | |9559, | | | |Appendix A.25)| +---------------------+-----------------------------+--------------+ | 0x3A9697| CodecSettings |Reclaimed (RFC| | | |9559, | | | |Appendix A.19)| +---------------------+-----------------------------+--------------+ | 0x3B4040| CodecInfoURL |Reclaimed (RFC| | | |9559, | | | |Appendix A.20)| +---------------------+-----------------------------+--------------+ | 0x3C83AB| PrevFilename |RFC 9559, | | | |Section | | | |5.1.2.4 | +---------------------+-----------------------------+--------------+ | 0x3CB923| PrevUUID |RFC 9559, | | | |Section | | | |5.1.2.3 | +---------------------+-----------------------------+--------------+ | 0x3E83BB| NextFilename |RFC 9559, | | | |Section | | | |5.1.2.6 | +---------------------+-----------------------------+--------------+ | 0x3EB923| NextUUID |RFC 9559, | | | |Section | | | |5.1.2.5 | +---------------------+-----------------------------+--------------+ | 0x3FFFFF| Reserved |RFC 9559 | +---------------------+-----------------------------+--------------+ |0x01000000-0x101FFFFE| Not valid for use as an |RFC 9559, | | | Element ID |Section 27.1 | +---------------------+-----------------------------+--------------+ | 0x1043A770| Chapters |RFC 9559, | | | |Section 5.1.7 | +---------------------+-----------------------------+--------------+ | 0x114D9B74| SeekHead |RFC 9559, | | | |Section 5.1.1 | +---------------------+-----------------------------+--------------+ | 0x1254C367| Tags |RFC 9559, | | | |Section 5.1.8 | +---------------------+-----------------------------+--------------+ | 0x1549A966| Info |RFC 9559, | | | |Section 5.1.2 | +---------------------+-----------------------------+--------------+ | 0x1654AE6B| Tracks |RFC 9559, | | | |Section 5.1.4 | +---------------------+-----------------------------+--------------+ | 0x18538067| Segment |RFC 9559, | | | |Section 5.1 | +---------------------+-----------------------------+--------------+ | 0x1941A469| Attachments |RFC 9559, | | | |Section 5.1.6 | +---------------------+-----------------------------+--------------+ | 0x1C53BB6B| Cues |RFC 9559, | | | |Section 5.1.5 | +---------------------+-----------------------------+--------------+ | 0x1F43B675| Cluster |RFC 9559, | | | |Section 5.1.3 | +---------------------+-----------------------------+--------------+ | 0x1FFFFFFF| Reserved |RFC 9559 | +---------------------+-----------------------------+--------------+
-
Table 53: Initial Contents of "Matroska Element IDs" Registry
-
27.2. Matroska Compression Algorithms Registry
-
IANA has created a new registry called the "Matroska Compression Algorithms" registry. The values correspond to the unsigned integer ContentCompAlgo value described in Section 5.1.4.1.31.6.
To register a new Compression Algorithm in this registry, one needs a Compression Algorithm value, a description, a Change Controller, and a Reference to a document describing the Compression Algorithm.
The Compression Algorithms are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 4-18446744073709551615.
Table 54 shows the initial contents of the "Matroska Compression Algorithms" registry. The Change Controller for the initial entries is the IETF.
+=======================+=============+===================+ | Compression Algorithm | Description | Reference | +=======================+=============+===================+ | 0 | zlib | RFC 9559, Section | | | | 5.1.4.1.31.6 | +-----------------------+-------------+-------------------+ | 1 | bzlib | RFC 9559, Section | | | | 5.1.4.1.31.6 | +-----------------------+-------------+-------------------+ | 2 | lzo1x | RFC 9559, Section | | | | 5.1.4.1.31.6 | +-----------------------+-------------+-------------------+ | 3 | Header | RFC 9559, Section | | | Stripping | 5.1.4.1.31.6 | +-----------------------+-------------+-------------------+
Table 54: Initial Contents of "Matroska Compression
Algorithms" Registry
27.3. Matroska Encryption Algorithms Registry
-
IANA has created a new registry called the "Matroska Encryption Algorithms" registry. The values correspond to the unsigned integer ContentEncAlgo value described in Section 5.1.4.1.31.9.
To register a new Encryption Algorithm in this registry, one needs an Encryption Algorithm value, a description, a Change Controller, and an optional Reference to a document describing the Encryption Algorithm.
The Encryption Algorithms are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 6-18446744073709551615.
Table 55 shows the initial contents of the "Matroska Encryption Algorithms" registry. The Change Controller for the initial entries is the IETF.
+======================+===============+===================+ | Encryption Algorithm | Description | Reference | +======================+===============+===================+ | 0 | Not encrypted | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+ | 1 | DES | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+ | 2 | 3DES | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+ | 3 | Twofish | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+ | 4 | Blowfish | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+ | 5 | AES | RFC 9559, Section | | | | 5.1.4.1.31.9 | +----------------------+---------------+-------------------+
Table 55: Initial Contents of "Matroska Encryption
Algorithms" Registry
27.4. Matroska AES Cipher Modes Registry
-
IANA has created a new registry called the "Matroska AES Cipher Modes" registry. The values correspond to the unsigned integer AESSettingsCipherMode value described in Section 5.1.4.1.31.12.
To register a new AES Cipher Mode in this registry, one needs an AES Cipher Mode value, a description, a Change Controller, and an optional Reference to a document describing the AES Cipher Mode.
The AES Cipher Modes are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 3-18446744073709551615.
The value 0 is not valid for use as an AES Cipher Mode.
Table 56 shows the initial contents of the "Matroska AES Cipher Modes" registry. The Change Controller for the initial entries is the IETF.
+=================+======================+===================+ | AES Cipher Mode | Description | Reference | +=================+======================+===================+ | 0 | Not valid for use as | RFC 9559, Section | | | an AES Cipher Mode | 5.1.4.1.31.12 | +-----------------+----------------------+-------------------+ | 1 | AES-CTR | RFC 9559, Section | | | | 5.1.4.1.31.12 | +-----------------+----------------------+-------------------+ | 2 | AES-CBC | RFC 9559, Section | | | | 5.1.4.1.31.12 | +-----------------+----------------------+-------------------+
Table 56: Initial Contents of "Matroska AES Cipher Modes"
Registry
27.5. Matroska Content Encoding Scopes Registry
-
IANA has created a new registry called the "Matroska Content Encoding Scopes" registry. The values correspond to the unsigned integer ContentEncodingScope value described in Section 5.1.4.1.31.3.
To register a new Content Encoding Scope in this registry, one needs a Content Encoding Scope value, a description, a Change Controller, and a Reference to a document describing the Content Encoding Scope.
The Content Encoding Scopes are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 0x8-0x8000000000000000.
The Content Encoding Scope is a bit-field value, so only power of 2 values can be registered.
The value 0 is not valid for use as a Content Encoding Scope.
Table 57 shows the initial contents of the "Matroska Content Encoding Scopes" registry. The Change Controller for the initial entries is the IETF.
+================+========================+===================+ | Content | Description | Reference | | Encoding Scope | | | +================+========================+===================+ | 0x0 | Not valid for use as a | RFC 9559, Section | | | Content Encoding Scope | 5.1.4.1.31.3 | +----------------+------------------------+-------------------+ | 0x1 | Block | RFC 9559, Section | | | | 5.1.4.1.31.3 | +----------------+------------------------+-------------------+ | 0x2 | Private | RFC 9559, Section | | | | 5.1.4.1.31.3 | +----------------+------------------------+-------------------+ | 0x4 | Next | RFC 9559, Section | | | | 5.1.4.1.31.3 | +----------------+------------------------+-------------------+
Table 57: Initial Contents of "Matroska Content Encoding
Scopes" Registry
27.6. Matroska Content Encoding Types Registry
-
IANA has created a new registry called the "Matroska Content Encoding Types" registry. The values correspond to the unsigned integer ContentEncodingType value described in Section 5.1.4.1.31.4.
To register a new Content Encoding Type in this registry, one needs a Content Encoding Type value, a description, a Change Controller, and a Reference to a document describing the Content Encoding Type.
The Content Encoding Types are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 2-18446744073709551615.
Table 58 shows the initial contents of the "Matroska Content Encoding Types" registry. The Change Controller for the initial entries is the IETF.
+=======================+=============+===================+ | Content Encoding Type | Description | Reference | +=======================+=============+===================+ | 0 | Compression | RFC 9559, Section | | | | 5.1.4.1.31.4 | +-----------------------+-------------+-------------------+ | 1 | Encryption | RFC 9559, Section | | | | 5.1.4.1.31.4 | +-----------------------+-------------+-------------------+
Table 58: Initial Contents of "Matroska Content
Encoding Types" Registry
27.7. Matroska Stereo Modes Registry
-
IANA has created a new registry called the "Matroska Stereo Modes" registry. The values correspond to the unsigned integer StereoMode value described in Section 5.1.4.1.28.3.
To register a new Stereo Mode in this registry, one needs a Stereo Mode value, a description, a Change Controller, and a Reference to a document describing the Stereo Mode.
The Stereo Modes are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 15-18446744073709551615.
Table 59 shows the initial contents of the "Matroska Stereo Modes" registry. The Change Controller for the initial entries is the IETF.
+=============+============================+===================+ | Stereo Mode | Description | Reference | +=============+============================+===================+ | 0 | mono | RFC 9559, Section | | | | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 1 | side by side (left eye | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 2 | top - bottom (right eye is | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 3 | top - bottom (left eye is | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 4 | checkboard (right eye is | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 5 | checkboard (left eye is | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 6 | row interleaved (right eye | RFC 9559, Section | | | is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 7 | row interleaved (left eye | RFC 9559, Section | | | is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 8 | column interleaved (right | RFC 9559, Section | | | eye is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 9 | column interleaved (left | RFC 9559, Section | | | eye is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 10 | anaglyph (cyan/red) | RFC 9559, Section | | | | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 11 | side by side (right eye | RFC 9559, Section | | | first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 12 | anaglyph (green/magenta) | RFC 9559, Section | | | | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 13 | both eyes laced in one | RFC 9559, Section | | | Block (left eye is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+ | 14 | both eyes laced in one | RFC 9559, Section | | | Block (right eye is first) | 5.1.4.1.28.3 | +-------------+----------------------------+-------------------+-
Table 59: Initial Contents of "Matroska Stereo Modes" Registry
-
27.8. Matroska Alpha Modes Registry
-
IANA has created a new registry called the "Matroska Alpha Modes" registry. The values correspond to the unsigned integer AlphaMode value described in Section 5.1.4.1.28.4.
To register a new Alpha Mode in this registry, one needs an Alpha Mode value, a description, a Change Controller, and an optional Reference to a document describing the Alpha Mode.
The Alpha Modes are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 2-18446744073709551615.
Table 60 shows the initial contents of the "Matroska Alpha Modes" registry. The Change Controller for the initial entries is the IETF.
+============+=============+================================+ | Alpha Mode | Description | Reference | +============+=============+================================+ | 0 | none | RFC 9559, Section 5.1.4.1.28.4 | +------------+-------------+--------------------------------+ | 1 | present | RFC 9559, Section 5.1.4.1.28.4 | +------------+-------------+--------------------------------+-
Table 60: Initial Contents of "Matroska Alpha Modes" Registry
-
27.9. Matroska Display Units Registry
-
IANA has created a new registry called the "Matroska Display Units" registry. The values correspond to the unsigned integer DisplayUnit value described in Section 5.1.4.1.28.14.
To register a new Display Unit in this registry, one needs a Display Unit value, a description, a Change Controller, and a Reference to a document describing the Display Unit.
The Display Units are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 5-18446744073709551615.
Table 61 shows the initial contents of the "Matroska Display Units" registry. The Change Controller for the initial entries is the IETF.
+==============+==============+=================================+ | Display Unit | Description | Reference | +==============+==============+=================================+ | 0 | pixels | RFC 9559, Section 5.1.4.1.28.14 | +--------------+--------------+---------------------------------+ | 1 | centimeters | RFC 9559, Section 5.1.4.1.28.14 | +--------------+--------------+---------------------------------+ | 2 | inches | RFC 9559, Section 5.1.4.1.28.14 | +--------------+--------------+---------------------------------+ | 3 | display | RFC 9559, Section 5.1.4.1.28.14 | | | aspect ratio | | +--------------+--------------+---------------------------------+ | 4 | unknown | RFC 9559, Section 5.1.4.1.28.14 | +--------------+--------------+---------------------------------+-
Table 61: Initial Contents of "Matroska Display Units" Registry
-
27.10. Matroska Horizontal Chroma Sitings Registry
-
IANA has created a new registry called the "Matroska Horizontal Chroma Sitings" registry. The values correspond to the unsigned integer ChromaSitingHorz value described in Section 5.1.4.1.28.23.
To register a new Horizontal Chroma Siting in this registry, one needs a Horizontal Chroma Siting value, a description, a Change Controller, and an optional Reference to a document describing the Horizontal Chroma Siting.
The Horizontal Chroma Sitings are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 3-18446744073709551615.
Table 62 shows the initial contents of the "Matroska Horizontal Chroma Sitings" registry. The Change Controller for the initial entries is the IETF.
+==========================+=============+===================+ | Horizontal Chroma Siting | Description | Reference | +==========================+=============+===================+ | 0 | unspecified | RFC 9559, Section | | | | 5.1.4.1.28.23 | +--------------------------+-------------+-------------------+ | 1 | left | RFC 9559, Section | | | collocated | 5.1.4.1.28.23 | +--------------------------+-------------+-------------------+ | 2 | half | RFC 9559, Section | | | | 5.1.4.1.28.23 | +--------------------------+-------------+-------------------+
Table 62: Initial Contents of "Matroska Horizontal Chroma
Sitings" Registry
27.11. Matroska Vertical Chroma Sitings Registry
-
IANA has created a new registry called the "Matroska Vertical Chroma Sitings" registry. The values correspond to the unsigned integer ChromaSitingVert value described in Section 5.1.4.1.28.24.
To register a new Vertical Chroma Siting in this registry, one needs a Vertical Chroma Siting value, a description, a Change Controller, and an optional Reference to a document describing the Vertical Chroma Siting.
The Vertical Chroma Sitings are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 3-18446744073709551615.
Table 63 shows the initial contents of the "Matroska Vertical Chroma Sitings" registry. The Change Controller for the initial entries is the IETF.
+========================+=============+===================+ | Vertical Chroma Siting | Description | Reference | +========================+=============+===================+ | 0 | unspecified | RFC 9559, Section | | | | 5.1.4.1.28.24 | +------------------------+-------------+-------------------+ | 1 | top | RFC 9559, Section | | | collocated | 5.1.4.1.28.24 | +------------------------+-------------+-------------------+ | 2 | half | RFC 9559, Section | | | | 5.1.4.1.28.24 | +------------------------+-------------+-------------------+
Table 63: Initial Contents of "Matroska Vertical Chroma
Sitings" Registry
27.12. Matroska Color Ranges Registry
-
IANA has created a new registry called the "Matroska Color Ranges" registry. The values correspond to the unsigned integer Range value described in Section 5.1.4.1.28.25.
To register a new Color Range in this registry, one needs a Color Range value, a description, a Change Controller, and a Reference to a document describing the Color Range.
The Color Ranges are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 4-18446744073709551615.
Table 64 shows the initial contents of the "Matroska Color Ranges" registry. The Change Controller for the initial entries is the IETF.
+=============+===============================+===================+ | Color Range | Description | Reference | +=============+===============================+===================+ | 0 | unspecified | RFC 9559, Section | | | | 5.1.4.1.28.25 | +-------------+-------------------------------+-------------------+ | 1 | broadcast range | RFC 9559, Section | | | | 5.1.4.1.28.25 | +-------------+-------------------------------+-------------------+ | 2 | full range (no clipping) | RFC 9559, Section | | | | 5.1.4.1.28.25 | +-------------+-------------------------------+-------------------+ | 3 | defined by MatrixCoefficients | RFC 9559, Section | | | / TransferCharacteristics | 5.1.4.1.28.25 | +-------------+-------------------------------+-------------------+-
Table 64: Initial Contents of "Matroska Color Ranges" Registry
-
27.13. Matroska Tags Target Types Registry
-
IANA has created a new registry called the "Matroska Tags Target Types" registry. The values correspond to the unsigned integer TargetTypeValue value described in Section 5.1.8.1.1.1.
To register a new Tags Target Type in this registry, one needs a Tags Target Type value, a description, a Change Controller, and a Reference to a document describing the Tags Target Type.
The Tags Target Types are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 1-9, 11-19, 21-29, 31-39, 41-49, 51-59, 61-69, and 71-18446744073709551615.
The value 0 is not valid for use as a Tags Target Type.
Table 65 shows the initial contents of the "Matroska Tags Target Types" registry. The Change Controller for the initial entries is the IETF.
+==================+==========================+===================+ | Tags Target Type | Description | Reference | +==================+==========================+===================+ | 70 | COLLECTION | RFC 9559, Section | | | | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 60 | EDITION / ISSUE / VOLUME | RFC 9559, Section | | | / OPUS / SEASON / SEQUEL | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 50 | ALBUM / OPERA / CONCERT | RFC 9559, Section | | | / MOVIE / EPISODE | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 40 | PART / SESSION | RFC 9559, Section | | | | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 30 | TRACK / SONG / CHAPTER | RFC 9559, Section | | | | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 20 | SUBTRACK / MOVEMENT / | RFC 9559, Section | | | SCENE | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 10 | SHOT | RFC 9559, Section | | | | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+ | 0 | Not valid for use as a | RFC 9559, Section | | | Tags Target Type | 5.1.8.1.1.1 | +------------------+--------------------------+-------------------+Table 65: Initial Contents of "Matroska Tags Target Types" Registry
27.14. Matroska Chapter Codec IDs Registry
-
IANA has created a new registry called the "Matroska Chapter Codec IDs" registry. The values correspond to the unsigned integer ChapProcessCodecID, ChapterTranslateCodec, and TrackTranslateCodec values described in Section 5.1.7.1.4.15.
To register a new Chapter Codec ID in this registry, one needs a Chapter Codec ID value, a description, a Change Controller, and a Reference to a document describing the Chapter Codec ID.
The Chapter Codec IDs are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 2-18446744073709551615.
Table 66 shows the initial contents of the "Matroska Chapter Codec IDs" registry. The Change Controller for the initial entries is the IETF.
+==================+=================+===================+ | Chapter Codec ID | Description | Reference | +==================+=================+===================+ | 0 | Matroska Script | RFC 9559, Section | | | | 5.1.7.1.4.15 | +------------------+-----------------+-------------------+ | 1 | DVD-menu | RFC 9559, Section | | | | 5.1.7.1.4.15 | +------------------+-----------------+-------------------+
Table 66: Initial Contents of "Matroska Chapter Codec
IDs" Registry
27.15. Matroska Projection Types Registry
-
IANA has created a new registry called the "Matroska Projection Types" registry. The values correspond to the unsigned integer ProjectionType value described in Section 5.1.4.1.28.42.
To register a new Projection Type in this registry, one needs a Projection Type value, a description, a Change Controller, and an optional Reference to a document describing the Projection Type.
The Projection Types are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 4-18446744073709551615.
Table 67 shows the initial contents of the "Matroska Projection Types" registry. The Change Controller for the initial entries is the IETF.
+=================+=================+===================+ | Projection Type | Description | Reference | +=================+=================+===================+ | 0 | rectangular | RFC 9559, Section | | | | 5.1.4.1.28.42 | +-----------------+-----------------+-------------------+ | 1 | equirectangular | RFC 9559, Section | | | | 5.1.4.1.28.42 | +-----------------+-----------------+-------------------+ | 2 | cubemap | RFC 9559, Section | | | | 5.1.4.1.28.42 | +-----------------+-----------------+-------------------+ | 3 | mesh | RFC 9559, Section | | | | 5.1.4.1.28.42 | +-----------------+-----------------+-------------------+
Table 67: Initial Contents of "Matroska Projection
Types" Registry
27.16. Matroska Track Types Registry
-
IANA has created a new registry called the "Matroska Track Types" registry. The values correspond to the unsigned integer TrackType value described in Section 5.1.4.1.3.
To register a new Track Type in this registry, one needs a Track Type value, a description, a Change Controller, and a Reference to a document describing the Track Type.
The Track Types are to be allocated according to the "Specification Required" policy [RFC8126]. Available values range from 4-15, 19-31, and 34-18446744073709551615.
The value 0 is not valid for use as a Track Type.
Table 68 shows the initial contents of the "Matroska Track Types" registry. The Change Controller for the initial entries is the IETF.
+============+===================+===================+ | Track Type | Description | Reference | +============+===================+===================+ | 0 | Not valid for use | RFC 9559, | | | as a Track Type | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 1 | video | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 2 | audio | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 3 | complex | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 16 | logo | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 17 | subtitle | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 18 | buttons | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 32 | control | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+ | 33 | metadata | RFC 9559, | | | | Section 5.1.4.1.3 | +------------+-------------------+-------------------+
Table 68: Initial Contents of "Matroska Track
Types" Registry
27.17. Matroska Track Plane Types Registry
-
IANA has created a new registry called the "Matroska Track Plane Types" registry. The values correspond to the unsigned integer TrackPlaneType value described in Section 5.1.4.1.30.4.
To register a new Track Plane Type in this registry, one needs a Track Plane Type value, a description, a Change Controller, and an optional Reference to a document describing the Track Plane Type.
The Track Plane Types are to be allocated according to the "First Come First Served" policy [RFC8126]. Available values range from 3-18446744073709551615.
Table 69 shows the initial contents of the "Matroska Track Plane Types" registry. The Change Controller for the initial entries is the IETF.
+==================+=============+================================+ | Track Plane Type | Description | Reference | +==================+=============+================================+ | 0 | left eye | RFC 9559, Section 5.1.4.1.30.4 | +------------------+-------------+--------------------------------+ | 1 | right eye | RFC 9559, Section 5.1.4.1.30.4 | +------------------+-------------+--------------------------------+ | 2 | background | RFC 9559, Section 5.1.4.1.30.4 | +------------------+-------------+--------------------------------+Table 69: Initial Contents of "Matroska Track Plane Types" Registry
27.18. Media Types
-
Matroska files and streams are found in three main forms: audio- video, audio-only, and (occasionally) stereoscopic video.
Historically, Matroska files and streams have used the following media types with an "x-" prefix. For better compatibility, a system SHOULD be able to handle both formats. Newer systems SHOULD NOT use the historic format and use the format that follows the format in [RFC6838] instead.
IANA has registered three media types per the templates (see [RFC6838]) in the following subsections.
27.18.1. For Files Containing Video Tracks
-
Type name: video Subtype name: matroska Required parameters: N/A Optional parameters: N/A Encoding considerations: As per RFCs 9559 and 8794 Security considerations: See Section 26 of RFC 9559. Interoperability considerations: Due to the extensibility of Matroska, it is possible to encounter files with unknown but valid EBML Elements. Readers should be ready to handle this case. The fixed byte order, octet boundaries, and UTF-8 usage allow for broad interoperability. Published specification: RFC 9559 Applications that use this media type: FFmpeg, VLC, etc. Fragment identifier considerations: N/A
Additional information:
Deprecated alias names for this type: video/x-matroska Magic number(s): N/A File extension(s): mkv Macintosh file type code(s): N/A Person & email address to contact for further information: IETF CELLAR WG (cellar@ietf.org) Intended usage: COMMON Restrictions on usage: None Author: IETF CELLAR WG Change controller: IETF
27.18.2. For Files Containing Audio Tracks with No Video Tracks
-
Type name: audio Subtype name: matroska Required parameters: N/A Optional parameters: N/A Encoding considerations: As per RFCs 9559 and 8794 Security considerations: See Section 26 of RFC 9559. Interoperability considerations: Due to the extensibility of Matroska, it is possible to encounter files with unknown but valid EBML Elements. Readers should be ready to handle this case. The fixed byte order, octet boundaries, and UTF-8 usage allow for broad interoperability. Published specification: RFC 9559 Applications that use this media type: FFmpeg, VLC, etc. Fragment identifier considerations: N/A
Additional information:
Deprecated alias names for this type: audio/x-matroska Magic number(s): N/A File extension(s): mka Macintosh file type code(s): N/A Person & email address to contact for further information: IETF CELLAR WG (cellar@ietf.org) Intended usage: COMMON Restrictions on usage: None Author: IETF CELLAR WG Change controller: IETF
27.18.3. For Files Containing a Stereoscopic Video Track
-
Type name: video Subtype name: matroska-3d Required parameters: N/A Optional parameters: N/A Encoding considerations: As per RFCs 9559 and 8794 Security considerations: See Section 26 of RFC 9559. Interoperability considerations: Due to the extensibility of Matroska, it is possible to encounter files with unknown but valid EBML Elements. Readers should be ready to handle this case. The fixed byte order, octet boundaries, and UTF-8 usage allow for broad interoperability. Published specification: RFC 9559 Applications that use this media type: FFmpeg, VLC, etc. Fragment identifier considerations: N/A
Additional information:
Deprecated alias names for this type: video/x-matroska-3d Magic number(s): N/A File extension(s): mk3d Macintosh file type code(s): N/A Person & email address to contact for further information: IETF CELLAR WG (cellar@ietf.org) Intended usage: COMMON Restrictions on usage: None Author: IETF CELLAR WG Change controller: IETF
28. References
28.1. Normative References
-
[CIE-1931] Wikipedia, "CIE 1931 color space",
<https://en.wikipedia.org/w/ index.php?title=CIE_1931_color_space&oldid=1242811504>. [ISO639-2] International Organization for Standardization, "Codes for the Representation of Names of Languages", ISO 639-2, December 2017, <https://www.loc.gov/standards/iso639- 2/php/code_list.php>. [ISO9899] International Organization for Standardization, "Information technology -- Programming languages -- C", ISO/IEC 9899:2018, June 2018, <https://www.iso.org/standard/74528.html>.[ITU-H.273]
ITU-T, "Coding-independent code points for video signal type identification", ITU-T Recommendation H.273, September 2023, <https://www.itu.int/rec/T-REC-H.273-202309-P/en>. [RFC1950] Deutsch, P. and J. Gailly, "ZLIB Compressed Data Format Specification version 3.3", RFC 1950, DOI 10.17487/RFC1950, May 1996, <https://www.rfc-editor.org/info/rfc1950>. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>. [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009, <https://www.rfc-editor.org/info/rfc5646>. [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013, <https://www.rfc-editor.org/info/rfc6838>. [RFC8081] Lilley, C., "The "font" Top-Level Media Type", RFC 8081, DOI 10.17487/RFC8081, February 2017, <https://www.rfc-editor.org/info/rfc8081>. [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. [RFC8794] Lhomme, S., Rice, D., and M. Bunkus, "Extensible Binary Meta Language", RFC 8794, DOI 10.17487/RFC8794, July 2020, <https://www.rfc-editor.org/info/rfc8794>. [RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May 2024, <https://www.rfc-editor.org/info/rfc9562>.
28.2. Informative References
-
[AVIFormat]
Microsoft Corporation, "AVI RIFF File Reference", June 2023, <https://docs.microsoft.com/en- us/windows/win32/directshow/avi-riff-file-reference>. [Blowfish] Schneier, B., "The Blowfish Encryption Algorithm", 1993, <https://www.schneier.com/academic/blowfish/>. [BZIP2] Seward, J., "bzip2", July 2019, <https://sourceware.org/bzip2/>.[DivXTrickTrack]
"Smooth FF/RW", December 2010, <https://web.archive.org/web/20101222001148/ http://labs.divx.com/node/16601>.[DivXWorldFonts]
"World Fonts", December 2010, <https://web.archive.org/web/20110214132246/ http://labs.divx.com/node/16602>.[DVD-Video]
DVD Forum, "DVD-Books: Part 3 DVD-Video Book", November 1995, <http://www.dvdforum.org/>. [Err7189] RFC Errata, Erratum ID 7189, RFC 8794, <https://www.rfc-editor.org/errata/eid7189>. [Err7191] RFC Errata, Erratum ID 7191, RFC 8794, <https://www.rfc-editor.org/errata/eid7191>. [FIPS197] National Institute of Standards and Technology (NIST), "Advanced Encryption Standard (AES)", FIPS PUB 197, DOI 10.6028/NIST.FIPS.197, November 2001, <https://csrc.nist.gov/publications/detail/fips/197/ final>.[FIPS46-3] National Institute of Standards and Technology (NIST),
"Data Encryption Standard (DES)", FIPS PUB 46, October 1999, <https://csrc.nist.gov/publications/detail/fips/46/3/ archive/1999-10-25>.[FourCC-RGB]
FOURCC, "RGB pixel formats", <https://web.archive.org/web/20160609214806/ https://www.fourcc.org/rgb.php>.[FourCC-YUV]
FOURCC, "YUV pixel formats", <https://web.archive.org/web/20160609214806/ https://www.fourcc.org/yuv.php>. [JPEG] ITU-T, "INFORMATION TECHNOLOGY - DIGITAL COMPRESSION AND CODING OF CONTINUOUS-TONE STILL IMAGES - REQUIREMENTS AND GUIDELINES", ITU-T Recommendation T.81, September 1992, <https://www.w3.org/Graphics/JPEG/itu-t81.pdf>.[libmatroska]
"libmatroska", March 2024, <https://github.com/Matroska-Org/libmatroska>. [LZO] Tarreau, W. and R. Rodgman, "LZO stream format as understood by Linux's LZO decompressor", October 2018, <https://www.kernel.org/doc/Documentation/lzo.txt>.[MatroskaCodec]
Lhomme, S., Bunkus, M., and D. Rice, "Matroska Media Container Codec Specifications", Work in Progress, Internet-Draft, draft-ietf-cellar-codec-13, 5 May 2024, <https://datatracker.ietf.org/doc/html/draft-ietf-cellar- codec-13>.[MatroskaTags]
Lhomme, S., Bunkus, M., and D. Rice, "Matroska Media Container Tag Specifications", Work in Progress, Internet- Draft, draft-ietf-cellar-tags-13, 5 May 2024, <https://datatracker.ietf.org/doc/html/draft-ietf-cellar- tags-13>. [MCF] "MCF specification, introduction", <http://mukoli.free.fr/mcf/>. [MSRGB] Microsoft Corporation, "Compression Enumeration", June 2021, <https://learn.microsoft.com/en- us/openspecs/windows_protocols/ms-wmf/4e588f70-bd92-4a6f- b77f-35d0feaf7a57>. [MSYUV16] Microsoft Corporation, "10-bit and 16-bit YUV Video Formats", November 2022, <https://learn.microsoft.com/en- us/windows/win32/medfound/10-bit-and-16-bit-yuv-video- formats>. [MSYUV8] Microsoft Corporation, "Recommended 8-Bit YUV Formats for Video Rendering", January 2021, <https://learn.microsoft.com/en-us/windows/win32/medfound/ recommended-8-bit-yuv-formats-for-video-rendering>. [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9, RFC 959, DOI 10.17487/RFC0959, October 1985, <https://www.rfc-editor.org/info/rfc959>. [RFC2083] Boutell, T., "PNG (Portable Network Graphics) Specification Version 1.0", RFC 2083, DOI 10.17487/RFC2083, March 1997, <https://www.rfc-editor.org/info/rfc2083>. [RFC3533] Pfeiffer, S., "The Ogg Encapsulation Format Version 0", RFC 3533, DOI 10.17487/RFC3533, May 2003, <https://www.rfc-editor.org/info/rfc3533>. [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet Denial-of-Service Considerations", RFC 4732, DOI 10.17487/RFC4732, December 2006, <https://www.rfc-editor.org/info/rfc4732>. [RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, June 2022, <https://www.rfc-editor.org/info/rfc9110>. [SMB-CIFS] Microsoft Corporation, "[MS-CIFS]: Common Internet File System (CIFS) Protocol", October 2020, <https://winprotocoldoc.blob.core.windows.net/ productionwindowsarchives/MS-CIFS/%5bMS-CIFS%5d.pdf>.[SP800-38A]
National Institute of Standards and Technology (NIST), "Recommendation for Block Cipher Modes of Operation: Methods and Techniques", DOI 10.6028/NIST.SP.800-38A, NIST Special Publication 800-38A, December 2001, <https://nvlpubs.nist.gov/nistpubs/Legacy/SP/ nistspecialpublication800-38a.pdf>.[SP800-67] National Institute of Standards and Technology (NIST),
"Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher", DOI 10.6028/NIST.SP.800-67r2, NIST Special Publication 800-67, November 2017, <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/ NIST.SP.800-67r2.pdf>. [Twofish] Schneier, B., Kelsey, J., Whiting, D., Wagner, D., Hall, C., and N. Ferguson, "Twofish: A 128-Bit Block Cipher", June 1998, <https://www.schneier.com/academic/archives/1998/06/ twofish_a_128-bit_bl.html>. [WebM-Enc] Galligan, F., "WebM Encryption", September 2016, <https://www.webmproject.org/docs/webm-encryption/>. [WebVTT] Pieters, S., Pfeiffer, S., Ed., Jaegenstedt, P., and I. Hickson, "WebVTT: The Web Video Text Tracks Format", W3C Candidate Recommendation, April 2019, <https://www.w3.org/TR/2019/CR-webvtt1-20190404/>.
Appendix A. Historic Deprecated Elements
-
As Matroska has evolved since 2002, many parts that were considered for use in the format were never used and often incorrectly designed. Many of the elements that were defined then are not found in any known files but were part of public specs. DivX also had a few custom elements that were designed for custom features.
In this appendix, we list elements that have a known ID that SHOULD NOT be reused to avoid colliding with existing files. These might be reassigned by IANA in the future if there are no more IDs for a given size. A short description of what each ID was used for is included, but the text is not normative.
A.1. SilentTracks Element
-
type / id: master / 0x5854 path: \Segment\Cluster\SilentTracks documentation: The list of tracks that are not used in that part of the stream. It is useful when using overlay tracks for seeking or deciding what track to use.
A.2. SilentTrackNumber Element
-
type / id: uinteger / 0x58D7 path: \Segment\Cluster\SilentTracks\SilentTrackNumber documentation: One of the track numbers that is not used from now on in the stream. It could change later if not specified as silent in a further Cluster.
A.3. BlockVirtual Element
-
type / id: binary / 0xA2 path: \Segment\Cluster\BlockGroup\BlockVirtual documentation: A Block with no data. It must be stored in the stream at the place the real Block would be in display order.
A.4. ReferenceVirtual Element
-
type / id: integer / 0xFD path: \Segment\Cluster\BlockGroup\ReferenceVirtual documentation: The Segment Position of the data that would otherwise be in position of the virtual block.
A.5. Slices Element
-
type / id: master / 0x8E path: \Segment\Cluster\BlockGroup\Slices documentation: Contains slices description.
A.6. TimeSlice Element
-
type / id: master / 0xE8 path: \Segment\Cluster\BlockGroup\Slices\TimeSlice documentation: Contains extra time information about the data contained in the Block. Being able to interpret this element is not required for playback.
A.7. LaceNumber Element
-
type / id: uinteger / 0xCC path: \Segment\Cluster\BlockGroup\Slices\TimeSlice\LaceNumber documentation: The reverse number of the frame in the lace (0 is the last frame, 1 is the next to last, etc.). Being able to interpret this element is not required for playback.
A.8. FrameNumber Element
-
type / id: uinteger / 0xCD path: \Segment\Cluster\BlockGroup\Slices\TimeSlice\FrameNumber documentation: The number of the frame to generate from this lace with this delay (allows for the generation of many frames from the same Block/Frame).
A.9. BlockAdditionID Element
-
type / id: uinteger / 0xCB path: \Segment\Cluster\BlockGroup\Slices\TimeSlice\BlockAdditionID documentation: The ID of the BlockAdditional element (0 is the main Block).
A.10. Delay Element
-
type / id: uinteger / 0xCE path: \Segment\Cluster\BlockGroup\Slices\TimeSlice\Delay documentation: The delay to apply to the element, expressed in Track Ticks; see Section 11.1.
A.11. SliceDuration Element
-
type / id: uinteger / 0xCF path: \Segment\Cluster\BlockGroup\Slices\TimeSlice\SliceDuration documentation: The duration to apply to the element, expressed in Track Ticks; see Section 11.1.
A.12. ReferenceFrame Element
-
type / id: master / 0xC8 path: \Segment\Cluster\BlockGroup\ReferenceFrame documentation: Contains information about the last reference frame. See [DivXTrickTrack].
A.13. ReferenceOffset Element
-
type / id: uinteger / 0xC9 path: \Segment\Cluster\BlockGroup\ReferenceFrame\ReferenceOffset documentation: The relative offset, in bytes, from the previous BlockGroup element for this Smooth FF/RW video track to the containing BlockGroup element. See [DivXTrickTrack].
A.14. ReferenceTimestamp Element
-
type / id: uinteger / 0xCA path: \Segment\Cluster\BlockGroup\ReferenceFrame\ReferenceTimestamp documentation: The timestamp of the BlockGroup pointed to by ReferenceOffset, expressed in Track Ticks; see Section 11.1. See [DivXTrickTrack].
A.15. EncryptedBlock Element
-
type / id: binary / 0xAF path: \Segment\Cluster\EncryptedBlock documentation: Similar to SimpleBlock (see Section 10.2), but the data inside the Block are Transformed (encrypted and/or signed).
A.16. MinCache Element
-
type / id: uinteger / 0x6DE7 path: \Segment\Tracks\TrackEntry\MinCache documentation: The minimum number of frames a player should be able to cache during playback. If set to 0, the reference pseudo-cache system is not used.
A.17. MaxCache Element
-
type / id: uinteger / 0x6DF8 path: \Segment\Tracks\TrackEntry\MaxCache documentation: The maximum cache size necessary to store referenced frames in and the current frame. 0 means no cache is needed.
A.18. TrackOffset Element
-
type / id: integer / 0x537F path: \Segment\Tracks\TrackEntry\TrackOffset documentation: A value to add to the Block's Timestamp, expressed in Matroska Ticks -- i.e., in nanoseconds; see Section 11.1. This can be used to adjust the playback offset of a track.
A.19. CodecSettings Element
-
type / id: utf-8 / 0x3A9697 path: \Segment\Tracks\TrackEntry\CodecSettings documentation: A string describing the encoding setting used.
A.20. CodecInfoURL Element
-
type / id: string / 0x3B4040 path: \Segment\Tracks\TrackEntry\CodecInfoURL documentation: A URL to find information about the codec used.
A.21. CodecDownloadURL Element
-
type / id: string / 0x26B240 path: \Segment\Tracks\TrackEntry\CodecDownloadURL documentation: A URL to download information about the codec used.
A.22. CodecDecodeAll Element
-
type / id: uinteger / 0xAA path: \Segment\Tracks\TrackEntry\CodecDecodeAll documentation: Set to 1 if the codec can decode potentially damaged data.
A.23. TrackOverlay Element
-
type / id: uinteger / 0x6FAB path: \Segment\Tracks\TrackEntry\TrackOverlay documentation: Specify that this track is an overlay track for the Track specified (in the u-integer). This means that when this track has a gap on SilentTracks, the overlay track should be used instead. The order of multiple TrackOverlay matters; the first one is the one that should be used. If the first one is not found, it should be the second, etc.
A.24. AspectRatioType Element
-
type / id: uinteger / 0x54B3 path: \Segment\Tracks\TrackEntry\Video\AspectRatioType documentation: Specifies the possible modifications to the aspect ratio.
A.25. GammaValue Element
-
type / id: float / 0x2FB523 path: \Segment\Tracks\TrackEntry\Video\GammaValue documentation: Gamma value.
A.26. FrameRate Element
-
type / id: float / 0x2383E3 path: \Segment\Tracks\TrackEntry\Video\FrameRate documentation: Number of frames per second. This value is informational only. It is intended for constant frame rate streams and should not be used for a variable frame rate TrackEntry.
A.27. ChannelPositions Element
-
type / id: binary / 0x7D7B path: \Segment\Tracks\TrackEntry\Audio\ChannelPositions documentation: Table of horizontal angles for each successive channel.
A.28. TrickTrackUID Element
-
type / id: uinteger / 0xC0 path: \Segment\Tracks\TrackEntry\TrickTrackUID documentation: The TrackUID of the Smooth FF/RW video in the paired EBML structure corresponding to this video track. See [DivXTrickTrack].
A.29. TrickTrackSegmentUID Element
-
type / id: binary / 0xC1 path: \Segment\Tracks\TrackEntry\TrickTrackSegmentUID documentation: The SegmentUUID of the Segment containing the track identified by TrickTrackUID. See [DivXTrickTrack].
A.30. TrickTrackFlag Element
-
type / id: uinteger / 0xC6 path: \Segment\Tracks\TrackEntry\TrickTrackFlag documentation: Set to 1 if this video track is a Smooth FF/RW track. If set to 1, MasterTrackUID and MasterTrackSegUID should be present, and BlockGroups for this track must contain ReferenceFrame structures. Otherwise, TrickTrackUID and TrickTrackSegUID must be present if this track has a corresponding Smooth FF/RW track. See [DivXTrickTrack].
A.31. TrickMasterTrackUID Element
-
type / id: uinteger / 0xC7 path: \Segment\Tracks\TrackEntry\TrickMasterTrackUID documentation: The TrackUID of the video track in the paired EBML structure that corresponds to this Smooth FF/RW track. See [DivXTrickTrack].
A.32. TrickMasterTrackSegmentUID Element
-
type / id: binary / 0xC4 path: \Segment\Tracks\TrackEntry\TrickMasterTrackSegmentUID documentation: The SegmentUUID of the Segment containing the track identified by MasterTrackUID. See [DivXTrickTrack].
A.33. ContentSignature Element
-
type / id: binary / 0x47E3 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentSignature documentation: A cryptographic signature of the contents.
A.34. ContentSigKeyID Element
-
type / id: binary / 0x47E4 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentSigKeyID documentation: This is the ID of the private key that the data was signed with.
A.35. ContentSigAlgo Element
-
type / id: uinteger / 0x47E5 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentSigAlgo documentation: The algorithm used for the signature.
A.36. ContentSigHashAlgo Element
-
type / id: uinteger / 0x47E6 path: \Segment\Tracks\TrackEntry\ContentEncodings\ContentEncoding\Co ntentEncryption\ContentSigHashAlgo documentation: The hash algorithm used for the signature.
A.37. CueRefCluster Element
-
type / id: uinteger / 0x97 path: \Segment\Cues\CuePoint\CueTrackPositions\CueReference\CueRefCl uster documentation: The Segment Position of the Cluster containing the referenced Block.
A.38. CueRefNumber Element
-
type / id: uinteger / 0x535F path: \Segment\Cues\CuePoint\CueTrackPositions\CueReference\CueRefNu mber documentation: Number of the referenced Block of Track X in the specified Cluster.
A.39. CueRefCodecState Element
-
type / id: uinteger / 0xEB path: \Segment\Cues\CuePoint\CueTrackPositions\CueReference\CueRefCo decState documentation: The Segment Position of the Codec State corresponding to this referenced element. 0 means that the data is taken from the initial TrackEntry.
A.40. FileReferral Element
-
type / id: binary / 0x4675 path: \Segment\Attachments\AttachedFile\FileReferral documentation: A binary value that a track/codec can refer to when the attachment is needed.
A.41. FileUsedStartTime Element
-
type / id: uinteger / 0x4661 path: \Segment\Attachments\AttachedFile\FileUsedStartTime documentation: The timestamp at which this optimized font attachment comes into context, expressed in Segment Ticks, which are based on TimestampScale. See [DivXWorldFonts].
A.42. FileUsedEndTime Element
-
type / id: uinteger / 0x4662 path: \Segment\Attachments\AttachedFile\FileUsedEndTime documentation: The timestamp at which this optimized font attachment goes out of context, expressed in Segment Ticks, which are based on TimestampScale. See [DivXWorldFonts].
A.43. TagDefaultBogus Element
-
type / id: uinteger / 0x44B4 path: \Segment\Tags\Tag\+SimpleTag\TagDefaultBogus documentation: A variant of the TagDefault element with a bogus element ID; see Section 5.1.8.1.2.4.
Authors' Addresses
-
Steve Lhomme
Email: slhomme@matroska.orgMoritz Bunkus
Email: moritz@bunkus.orgDave Rice
Email: dave@dericed.com