A Codec Mapping
is a set of attributes to identify, name, and contextualize the format
and characteristics of encoded data that can be contained within Matroska Clusters.
Each TrackEntry
used within Matroska MUST reference a defined Codec Mapping
using the
Codec ID
to identify and describe the format of the encoded data in its associated Clusters.
This Codec ID
is a unique registered identifier that represents the encoding stored within
the Track
. Certain encodings MAY also require some form of codec initialization
to provide its decoder with context and technical metadata.
The intention behind this list is not to list all existing audio and video codecs,
but rather to list those codecs that are currently supported in Matroska and therefore
need a well defined Codec ID
so that all developers supporting Matroska will use the
same Codec ID
. If you feel we missed support for a very important codec, please tell
us on our development mailing list (cellar at ietf.org).
Support for a codec is defined in Matroska with the following values.
Each codec supported for storage in Matroska MUST have a unique Codec ID
.
Each Codec ID
MUST be prefixed with the string from the following table according to
the associated type of the codec. All characters of a Codec ID Prefix
MUST be
capital letters (A-Z) except for the last character of a Codec ID Prefix
which MUST be
an underscore ("_").
Codec Type | Codec ID Prefix |
---|---|
Video | "V_" |
Audio | "A_" |
Subtitle | "S_" |
Button | "B_" |
Each Codec ID
MUST include a Major Codec ID
immediately following the Codec ID Prefix
.
A Major Codec ID
MAY be followed by an OPTIONAL Codec ID Suffix
to communicate a refinement
of the Major Codec ID
. If a Codec ID Suffix
is used, then the Codec ID
MUST include a
forward slash ("/") as a separator between the Major Codec ID
and the Codec ID Suffix
.
The Major Codec ID
MUST be composed of only capital letters (A-Z) and numbers (0-9).
The Codec ID Suffix
MUST be composed of only capital letters (A-Z), numbers (0-9),
underscore ("_"), and forward slash ("/").
The following table provides examples of valid Codec IDs
and their components:
Codec ID Prefix | Major Codec ID | Separator | Codec ID Suffix | Codec ID |
---|---|---|---|---|
A_ | AAC | / | MPEG2/LC/SBR | A_AAC/MPEG2/LC/SBR |
V_ | MPEG4 | / | ISO/ASP | V_MPEG4/ISO/ASP |
V_ | MPEG1 | V_MPEG1 |
Each encoding supported for storage in Matroska MUST have a Codec Name
.
The Codec Name
provides a readable label for the encoding.
An optional description for the encoding. This value is only intended for human consumption.
Each encoding supported for storage in Matroska MUST have a defined Initialization.
The Initialization MUST describe the storage of data necessary to initialize the decoder,
which MUST be stored within the CodecPrivate
element. When the Initialization is updated
within a track, then that updated Initialization data MUST be written into the CodecState
element
of the first Cluster
to require it. If the encoding does not require any form of Initialization,
then none
MUST be used to define the Initialization and the CodecPrivate
element
SHOULD NOT be written and MUST be ignored. Data that is defined Initialization to be
stored in the CodecPrivate
element is known as Private Data
.
Additional data that contextualizes or supplements a Block
can be stored within
the BlockAdditional
element of a BlockMore
element. This BlockAdditional
data MAY
be passed to the associated decoder along with the content of the Block
element.
Each BlockAdditional
is coupled with a BlockAddID
that identifies the kind of data
it contains. The following table defines the meanings of BlockAddID
values.
BlockAddID Value | Definition |
---|---|
0 | Invalid. |
1 | Indicates that the context of the BlockAdditional data is defined by the corresponding Codec Mapping . |
2 or greater | BlockAddID values of 2 and greater are mapped to the BlockAddIDValue of the BlockAdditionMapping of the associated Track . |
The values of BlockAddID
that are 2 of greater have no semantic meaning, but simply
associate the BlockMore
element with a BlockAdditionMapping
of the associated Track
.
See (#block-additional-mapping) on Block Additional Mappings
for more information.
The following XML depicts the nested elements of a BlockGroup
element with an example of BlockAdditions
:
<BlockGroup>
<Block>{Binary data of a VP9 video frame in YUV}</Block>
<BlockAdditions>
<BlockMore>
<BlockAddID>1</BlockAddID>
<BlockAdditional>
{alpha channel encoding to supplement the VP9 frame}
</BlockAdditional>
</BlockMore>
</BlockAdditions>
</BlockGroup>
Documentation of the associated normative and informative references for the codec is RECOMMENDED.
A timestamp, expressed in [@!RFC3339] that notes when support for the Codec Mapping
within Matroska was deprecated. If a Codec Mapping
is defined with a Deprecation Date
,
then it is RECOMMENDED that Matroska Writers SHOULD NOT use the Codec Mapping
after the Deprecation Date
.
A Codec Mapping
MAY only be defined with a Superseded By
value, if it has an
expressed Deprecation Date
. If used, the Superseded By
value MUST store
the Codec ID
of another Codec Mapping
that has superseded the Codec Mapping
.
Creators of new Codec Mappings
to be used in the context of Matroska:
-
SHOULD assume that all
Codec Mappings
they create might become standardized, public, commonly deployed, or usable across multiple implementations. -
SHOULD employ meaningful values for
Codec ID
andCodec Name
that they have reason to believe are currently unused. -
SHOULD NOT prefix their
Codec ID
with "X_" or similar constructs.
These recommendations are based on [@!RFC6648, section 3].
Codec ID: V_MS/VFW/FOURCC
Codec Name: Microsoft (TM) Video Codec Manager (VCM)
Description: The private data contains the VCM structure BITMAPINFOHEADER including the extra private bytes, as defined by Microsoft. The data are stored in little-endian format (like on IA32 machines). Where is the Huffman table stored in HuffYUV, not AVISTREAMINFO ??? And the FourCC, not in AVISTREAMINFO.fccHandler ???
Initialization: Private Data
contains the VCM structure BITMAPINFOHEADER including the extra private bytes,
as defined by Microsoft in https://msdn.microsoft.com/en-us/library/windows/desktop/dd183376(v=vs.85).aspx.
Citation: https://msdn.microsoft.com/en-us/library/windows/desktop/dd183376(v=vs.85).aspx
Codec ID: V_UNCOMPRESSED
Codec Name: Video, raw uncompressed video frames
Description: All details about the used color specs and bit depth are to be put/read from the TrackEntry\Video\UncompressedFourCC
elements.
Initialization: none
Codec ID: V_MPEG4/ISO/SP
Codec Name: MPEG4 ISO simple profile (DivX4)
Description: Stream was created via improved codec API (UCI) or even transmuxed from AVI (no b-frames in Simple Profile), frame order is coding order.
Initialization: none
Codec ID: V_MPEG4/ISO/ASP
Codec Name: MPEG4 ISO advanced simple profile (DivX5, XviD, FFMPEG)
Description: Stream was created via improved codec API (UCI) or transmuxed from MP4, not simply transmuxed from AVI.
Note there are differences how b-frames are handled in these original streams,
when being compared to a VfW created stream, as here there are no
dummy frames inserted,
the frame order is exactly the same as the coding order, same as in MP4 streams.
Initialization: none
Codec ID: V_MPEG4/ISO/AP
Codec Name: MPEG4 ISO advanced profile
Description: Stream was created via improved codec API (UCI) or transmuxed from MP4, not simply transmuxed from AVI.
Note there are differences how b-frames are handled in these original streams,
when being compared to a VfW created stream, as here there are no
dummy frames inserted,
the frame order is exactly the same as the coding order, same as in MP4 streams.
Initialization: none
Codec ID: V_MPEG4/MS/V3
Codec Name: Microsoft (TM) MPEG4 V3
Description: Microsoft (TM) MPEG4 V3 and derivates, means DivX3, Angelpotion, SMR, etc.; stream was created using VfW codec or transmuxed from AVI; note that V1/V2 are covered in VfW compatibility mode.
Initialization: none
Codec ID: V_MPEG1
Codec Name: MPEG 1
Description: The Matroska video stream will contain a demuxed Elementary Stream (ES), where block boundaries are still to be defined. It's RECOMMENDED to use MPEG2MKV.exe for creating those files, and to compare the results with self-made implementations
Initialization: none
Codec ID: V_MPEG2
Codec Name: MPEG 2
Description: The Matroska video stream will contain a demuxed Elementary Stream (ES), where block boundaries are still to be defined. It's RECOMMENDED to use MPEG2MKV.exe for creating those files, and to compare the results with self-made implementations
Initialization: none
Codec ID: V_MPEG4/ISO/AVC
Codec Name: AVC/H.264
Description: Individual pictures (which could be a frame, a field, or 2 fields having the same timestamp) of AVC/H.264 stored as described in [@!ISO.14496-15].
Initialization: The Private Data
contains a AVCDecoderConfigurationRecord
structure, as defined in [@!ISO.14496-15].
For legacy reasons, because Block Additional Mappings
are preferred; see (#block-addition-mappings),
the AVCDecoderConfigurationRecord
structure MAY be followed by an extension block beginning
with a 4-byte extension block size field in big-endian byte order which is the size of the extension block
minus 4 (excluding the size of the extension block size field) and a 4-byte field corresponding
to a BlockAddIDType
of "mvcC" followed by a content corresponding to the content of BlockAddIDExtraData
for mvcC
; see (#mvcc).
Codec ID: V_MPEGH/ISO/HEVC
Codec Name: HEVC/H.265
Description: Individual pictures (which could be a frame, a field, or 2 fields having the same timestamp) of HEVC/H.265 stored as described in [@!ISO.14496-15].
Initialization: The Private Data
contains a HEVCDecoderConfigurationRecord
structure, as defined in [@!ISO.14496-15].
Codec ID: V_MPEGI/ISO/VVC
Codec Name: VVC/H.266
Description: Individual pictures (which could be a frame, a field, or 2 fields having the same timestamp) of VVC/H.266 stored as described in [@!ISO.14496-15].
Initialization: The Private Data
contains a VVCDecoderConfigurationRecord
structure, as defined in [@!ISO.14496-15].
Codec ID: V_AVS2
Codec Name: AVS2-P2/IEEE.1857.4
Description: Individual pictures of AVS2-P2 stored as described in the second part of [@!IEEE.1857-4].
Initialization: none.
Codec ID: V_AVS3
Codec Name: AVS3-P2/IEEE.1857.10
Description: Individual pictures of AVS3-P2 stored as described in the second part of [@!IEEE.1857-10].
Initialization: none.
Codec ID: V_REAL/RV10
Codec Name: RealVideo 1.0 aka RealVideo 5
Description: Individual slices from the Real container are combined into a single frame.
Initialization: The Private Data
contains a real_video_props_t
structure in big-endian byte order as found in librmff.
Codec ID: V_REAL/RV20
Codec Name: RealVideo G2 and RealVideo G2+SVT
Description: Individual slices from the Real container are combined into a single frame.
Initialization: The Private Data
contains a real_video_props_t
structure in big-endian byte order as found in librmff.
Codec ID: V_REAL/RV30
Codec Name: RealVideo 8
Description: Individual slices from the Real container are combined into a single frame.
Initialization: The Private Data
contains a real_video_props_t
structure in big-endian byte order as found in librmff.
Codec ID: V_REAL/RV40
Codec Name: rv40 : RealVideo 9
Description: Individual slices from the Real container are combined into a single frame.
Initialization: The Private Data
contains a real_video_props_t
structure in big-endian byte order as found in librmff.
Codec ID: V_QUICKTIME
Codec Name: Video taken from QuickTime(TM) files
Description: Several codecs as stored in QuickTime (e.g., Sorenson or Cinepak).
Initialization: The Private Data
contains all additional data that is stored in the 'stsd' (sample description) atom
in the QuickTime file after the mandatory video descriptor structure
(starting with the size and FourCC fields). For an explanation of the QuickTime file format read QuickTime File Format Specification.
Codec ID: V_THEORA
Codec Name: Theora
Initialization: The Private Data
contains the first three Theora packets in order. The lengths of the packets precedes them. The actual layout is:
- Byte 1: number of distinct packets
#p
minus one inside the CodecPrivate block. This MUST be "2" for current (as of 2016-07-08) Theora headers. - Bytes 2..n: lengths of the first
#p
packets, coded in Xiph-style lacing. The length of the last packet is the length of the CodecPrivate block minus the lengths coded in these bytes minus one. - Bytes n+1..: The Theora identification header, followed by the commend header followed by the codec setup header. Those are described in the Theora specs.
Codec ID: V_PRORES
Codec Name: Apple ProRes
Initialization: The Private Data
contains the FourCC as found in MP4 movies:
- ap4x: ProRes 4444 XQ
- ap4h: ProRes 4444
- apch: ProRes 422 High Quality
- apcn: ProRes 422 Standard Definition
- apcs: ProRes 422 LT
- apco: ProRes 422 Proxy
- aprh: ProRes RAW High Quality
- aprn: ProRes RAW Standard Definition
this page for more technical details on ProRes
Codec ID: V_VP8
Codec Name: VP8 Codec format
Description: VP8 is an open and royalty free video compression format developed by Google and created by On2 Technologies as a successor to VP7. [@!RFC6386]
Codec BlockAdditions: A single-channel encoding of an alpha channel MAY be stored in BlockAdditions
. The BlockAddId
of the BlockMore
containing these data MUST be 1.
Initialization: none
Codec ID: V_VP9
Codec Name: VP9 Codec format
Description: VP9 is an open and royalty free video compression format developed by Google as a successor to VP8. Draft VP9 Bitstream and Decoding Process Specification
Codec BlockAdditions: A single-channel encoding of an alpha channel MAY be stored in BlockAdditions
. The BlockAddId
of the BlockMore
containing these data MUST be 1.
Initialization: none
Codec ID: V_FFV1
Codec Name: FF Video Codec 1
Description: FFV1 is a lossless intra-frame video encoding format designed to efficiently compress video data in a variety of pixel formats. Compared to uncompressed video, FFV1 offers storage compression, frame fixity, and self-description, which makes FFV1 useful as a preservation or intermediate video format. Draft FFV1 Specification
Initialization: For FFV1 versions 0 or 1, Private Data
SHOULD NOT be written. For FFV1 version 3 or greater, the Private Data
MUST contain the FFV1 Configuration Record structure, as defined in https://tools.ietf.org/html/draft-ietf-cellar-ffv1-04#section-4.2, and no other data.
Codec ID: A_MPEG/L3
Codec Name: MPEG Audio 1, 2, 2.5 Layer III
Description: The data contain everything needed for playback in the MPEG Audio header of each frame. Corresponding ACM wFormatTag : 0x0055
Initialization: none
Codec ID: A_MPEG/L2
Codec Name: MPEG Audio 1, 2 Layer II
Description: The data contain everything needed for playback in the MPEG Audio header of each frame. Corresponding ACM wFormatTag : 0x0050
Initialization: none
Codec ID: A_MPEG/L1
Codec Name: MPEG Audio 1, 2 Layer I
Description: The data contain everything needed for playback in the MPEG Audio header of each frame. Corresponding ACM wFormatTag : 0x0050
Initialization: none
Codec ID: A_PCM/INT/BIG
Codec Name: PCM Integer Big Endian
Description: The audio bit depth MUST be read and set from the BitDepth
element. Audio samples MUST be considered as signed values,
except if the audio bit depth is 8 which MUST be interpreted as unsigned values. Corresponding ACM wFormatTag : ???
Initialization: none
Codec ID: A_PCM/INT/LIT
Codec Name: PCM Integer Little Endian
Description: The audio bit depth MUST be read and set from the BitDepth
element. Audio samples MUST be considered as signed values,
except if the audio bit depth is 8 which MUST be interpreted as unsigned values. Corresponding ACM wFormatTag : 0x0001
Initialization: none
Codec ID: A_PCM/FLOAT/IEEE
Codec Name: Floating-Point, IEEE compatible
Description: The audio bit depth MUST be read and set from the BitDepth
element (32 bit in most cases).
The floats are stored as defined in [@!IEEE.754] and in little-endian order. Corresponding ACM wFormatTag : 0x0003
Initialization: none
Codec ID: A_MPC
Codec Name: MPC (musepack) SV8
Description: The main developer for musepack has requested that we wait until the SV8 framing has been fully defined for musepack before defining how to store it in Matroska.
Codec ID: A_AC3
Codec Name: (Dolby™) AC3
Description: BSID <= 8 !! The private data is void ??? Corresponding ACM wFormatTag : 0x2000 ; channel number have to be read from the corresponding audio element
Codec ID: A_AC3/BSID9
Codec Name: (Dolby™) AC3
Description: The ac3 frame header has, similar to the mpeg-audio header a version field. Normal ac3 is defined as bitstream id 8 (5 Bits, numbers are 0-15). Everything below 8 is still compatible with all decoders that handle 8 correctly. Everything higher are additions that break decoder compatibility. For the samplerates 24kHz (00); 22,05kHz (01) and 16kHz (10) the BSID is 9 For the samplerates 12kHz (00); 11,025kHz (01) and 8kHz (10) the BSID is 10
Initialization: none
Codec ID: A_AC3/BSID10
Codec Name: (Dolby™) AC3
Description: The ac3 frame header has, similar to the mpeg-audio header a version field. Normal ac3 is defined as bitstream id 8 (5 Bits, numbers are 0-15). Everything below 8 is still compatible with all decoders that handle 8 correctly. Everything higher are additions that break decoder compatibility. For the samplerates 24kHz (00); 22,05kHz (01) and 16kHz (10) the BSID is 9 For the samplerates 12kHz (00); 11,025kHz (01) and 8kHz (10) the BSID is 10
Initialization: none
Codec ID: A_ALAC
Codec Name: ALAC (Apple Lossless Audio Codec)
Initialization: The Private Data
contains ALAC's magic cookie (both the codec specific configuration as well as the optional channel layout information).
Its format is described in ALAC's official source code.
Codec ID: A_DTS
Codec Name: Digital Theatre System
Description: Supports DTS, DTS-ES, DTS-96/26, DTS-HD High Resolution Audio and DTS-HD Master Audio. The private data is void. Corresponding ACM wFormatTag : 0x2001
Initialization: none
Codec ID: A_DTS/EXPRESS
Codec Name: Digital Theatre System Express
Description: DTS Express (a.k.a. LBR) audio streams. The private data is void. Corresponding ACM wFormatTag : 0x2001
Initialization: none
Codec ID: A_DTS/LOSSLESS
Codec Name: Digital Theatre System Lossless
Description: DTS Lossless audio that does not have a core substream. The private data is void. Corresponding ACM wFormatTag : 0x2001
Initialization: none
Codec ID: A_VORBIS
Codec Name: Vorbis
Initialization: The Private Data
contains the first three Vorbis packet in order. The lengths of the packets precedes them. The actual layout is:
- Byte 1: number of distinct packets
#p
minus one inside the CodecPrivate block. This MUST be "2" for current (as of 2016-07-08) Vorbis headers. - Bytes 2..n: lengths of the first
#p
packets, coded in Xiph-style lacing. The length of the last packet is the length of the CodecPrivate block minus the lengths coded in these bytes minus one. - Bytes n+1..: The Vorbis identification header, followed by the Vorbis comment header followed by the codec setup header.
Codec ID: A_FLAC
Codec Name: FLAC (Free Lossless Audio Codec)
Initialization: The Private Data
contains all the header/metadata packets before the first data packet.
These include the first header packet containing only the word fLaC
as well as all metadata packets.
Codec ID: A_REAL/14_4
Codec Name: Real Audio 1
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_REAL/28_8
Codec Name: Real Audio 2
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_REAL/COOK
Codec Name: Real Audio Cook Codec (codename: Gecko)
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_REAL/SIPR
Codec Name: Sipro Voice Codec
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_REAL/RALF
Codec Name: Real Audio Lossless Format
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_REAL/ATRC
Codec Name: Sony Atrac3 Codec
Initialization: The Private Data
contains either the "real_audio_v4_props_t" or the "real_audio_v5_props_t" structure
(differentiated by their "version" field; big-endian byte order) as found in librmff.
Codec ID: A_MS/ACM
Codec Name: Microsoft(TM) Audio Codec Manager (ACM)
Description: The data are stored in little-endian format (like on IA32 machines).
Initialization: The Private Data
contains the [@!WAVEFORMATEX] structure including the extra format information bytes.
The structure is stored without packing or padding bytes.
A WORD
corresponds to a signed 2 octets integer, DWORD
corresponds to a signed 4 octets integer.
The extra format information are appended after the WAVEFORMATEX octets.
Codec ID: A_AAC/MPEG2/MAIN
Codec Name: MPEG2 Main Profile
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG2/LC
Codec Name: Low Complexity
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG2/LC/SBR
Codec Name: Low Complexity with Spectral Band Replication
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG2/SSR
Codec Name: Scalable Sampling Rate
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG4/MAIN
Codec Name: MPEG4 Main Profile
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG4/LC
Codec Name: Low Complexity
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG4/LC/SBR
Codec Name: Low Complexity with Spectral Band Replication
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG4/SSR
Codec Name: Scalable Sampling Rate
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_AAC/MPEG4/LTP
Codec Name: Long Term Prediction
Description: Channel number and sample rate have to be read from the corresponding audio element. Audio stream is stripped from ADTS headers and normal Matroska frame based muxing scheme is applied. AAC audio always uses wFormatTag 0xFF.
Initialization: none
Codec ID: A_QUICKTIME
Codec Name: Audio taken from QuickTime(TM) files
Description: Several codecs as stored in QuickTime (e.g., QDesign Music v1 or v2).
Initialization: The Private Data
contains all additional data that is stored in the 'stsd' (sample description) atom
in the QuickTime file after the mandatory sound descriptor structure (starting with the size and FourCC fields).
For an explanation of the QuickTime file format read QuickTime File Format Specification.
Codec ID: A_QUICKTIME/QDMC
Codec Name: QDesign Music
Description:
Initialization: The Private Data
contains all additional data that is stored in the 'stsd' (sample description) atom
in the QuickTime file after the mandatory sound descriptor structure (starting with the size and FourCC fields).
For an explanation of the QuickTime file format read QuickTime File Format Specification.
Superseded By: A_QUICKTIME
Codec ID: A_QUICKTIME/QDM2
Codec Name: QDesign Music v2
Description:
Initialization: The Private Data
contains all additional data that is stored in the 'stsd' (sample description) atom
in the QuickTime file after the mandatory sound descriptor structure (starting with the size and FourCC fields).
For an explanation of the QuickTime file format read QuickTime File Format Specification.
Superseded By: A_QUICKTIME
Codec ID: A_TTA1
Codec Name: The True Audio lossless audio compressor
Description: TTA format description
Each frame is kept intact, including the CRC32. The header and seektable are dropped. SamplingFrequency
, Channels
and BitDepth
are used in the TrackEntry
. wFormatTag = 0x77A1
Initialization: none
Codec ID: A_WAVPACK4
Codec Name: WavPack lossless audio compressor
Description: The Wavpack packets consist of a stripped header followed by the frame data. For multi-track (> 2 tracks) a frame consists of many packets. For more details, check the WavPack muxing description.
Codec BlockAdditions: For hybrid A_WAVPACK4
encodings (that include a lossy encoding with a supplemental correction
to produce a lossless encoding), the correction part is stored in BlockAdditional.
The BlockAddId
of the BlockMore
containing these data MUST be 1.
Initialization: none
Codec ID: A_ATRAC/AT1
Codec Name: Sony ATRAC1 Codec
Description: The original ATRAC codec by Sony, mainly used in MiniDisc platforms. The core technical details on ATRAC1 can be found in [@?AtracAES]. An example encoder/decoder can be found at [@?atracdenc].
Initialization: None
Codec ID: S_TEXT/UTF8
Codec Name: UTF-8 Plain Text
Description: Basic text subtitles. For more information see (#subtitles) on Subtitles.
Codec ID: S_TEXT/SSA
Codec Name: Subtitles Format
Description: The [Script Info] and [V4 Styles] sections are stored in the codecprivate. Each event is stored in its own Block
.
For more information see (#ssa-ass-subtitles) on SSA/ASS.
Codec ID: S_TEXT/ASS
Codec Name: Advanced Subtitles Format
Description: The [Script Info] and [V4 Styles] sections are stored in the codecprivate. Each event is stored in its own Block
.
For more information see (#ssa-ass-subtitles) on SSA/ASS.
Codec ID: S_TEXT/WEBVTT
Codec Name: Web Video Text Tracks Format (WebVTT)
Description: Advanced text subtitles. For more information see (#webvtt) on WebVTT.
Codec ID: S_IMAGE/BMP
Codec Name: Bitmap
Description: Basic image based subtitle format; The subtitles are stored as images, like in the DVD [@?DVD-Video]. The timestamp in the block header of Matroska indicates the start display time, the duration is set with the Duration element. The full data for the subtitle bitmap is stored in the Block's data section.
Codec ID: S_DVBSUB
Codec Name: Digital Video Broadcasting (DVB) subtitles
Description: This is the graphical subtitle format used in the Digital Video Broadcasting standard. For more information see (#digital-video-broadcasting-dvb-subtitles) on Digital Video Broadcasting (DVB).
Codec ID: S_VOBSUB
Codec Name: VobSub subtitles
Description: The same subtitle format used on DVDs [@?DVD-Video]. Supported is only format version 7 and newer.
VobSubs consist of two files, the .idx containing information, and the .sub, containing the actual data.
The .idx file is stripped of all empty lines, of all comments and of lines beginning with alt:
or langidx:
.
The line beginning with id:
SHOULD be transformed into the appropriate Matroska track language element
and is discarded. All remaining lines but the ones containing timestamps and file positions
are put into the CodecPrivate
element.
For each line containing the timestamp and file position data is read from the appropriate position in the .sub file. This data consists of a MPEG program stream which in turn contains SPU packets. The MPEG program stream data is discarded, and each SPU packet is put into one Matroska frame.
Codec ID: S_HDMV/PGS
Codec Name: HDMV presentation graphics subtitles (PGS)
Description: This is the graphical subtitle format used on Blu-rays. For more information, see (#hdmv-text-subtitles) on HDMV text presentation.
Codec ID: S_HDMV/TEXTST
Codec Name: HDMV text subtitles
Description: This is the textual subtitle format used on Blu-rays. For more information, see (#hdmv-presentation-graphics-subtitles) on HDMV graphics presentation.
Codec ID: S_KATE
Codec Name: Karaoke And Text Encapsulation
Description: A subtitle format developed for ogg. The mapping for Matroska is described on the Xiph wiki. As for Theora and Vorbis, Kate headers are stored in the private data as xiph-laced packets.
Codec ID: S_ARIBSUB
Codec Name: ARIB STD-B24 subtitles
Description: This is the textual subtitle format used in the ISDB/ARIB broadcasting standard. For more information see (#arib-isdb-subtitles) on ARIB (ISDB) subtitles.
Codec ID: B_VOBBTN
Codec Name: VobBtn Buttons
Description: Based on MPEG/VOB PCI packets. The file contains a header consisting of the string "butonDVD" followed by the width and height in pixels (16-bit integer each) and 4 reserved bytes. The rest is full PCI packets.
Registered BlockAddIDType
are:
Block type identifier: 0
Block type name: Use BlockAddIDValue
Description: This value indicates that the actual type is stored in BlockAddIDValue
instead.
This value is expected to be used when it is important to have a strong compatibility
with players or derived formats not supporting BlockAdditionMapping
but using BlockAdditions
with an unknown BlockAddIDValue
, and SHOULD NOT be used if it is possible to use another value.
Block type identifier: 1
Block type name: Opaque data
Description: the BlockAdditional
data is interpreted as opaque additional data passed to the codec
with the Block data. BlockAddIDValue
MUST be 1.
Block type identifier: 4
Block type name: ITU T.35 metadata
Description: the BlockAdditional
data is interpreted as ITU T.35 metadata, as defined by ITU-T T.35
terminal codes. BlockAddIDValue
MUST be 4.
Block type identifier: 0x61766345
Block type name: Dolby Vision enhancement-layer AVC configuration
Description: the BlockAddIDExtraData
data is interpreted as the Dolby Vision enhancement-layer AVC
configuration box as described in [@!DolbyVisionWithinIso]. This extension MUST NOT
be used if Codec ID
is not V_MPEG4/ISO/AVC
.
Block type identifier: 0x64766343
Block type name: Dolby Vision configuration
Description: the BlockAddIDExtraData
data is interpreted as DOVIDecoderConfigurationRecord
structure, as defined in [@!DolbyVisionWithinIso],
for Dolby Vision profiles less than and equal to 7.
Block type identifier: 0x64767643
Block type name: Dolby Vision configuration
Description: the BlockAddIDExtraData
data is interpreted as DOVIDecoderConfigurationRecord
structure, as defined in [@!DolbyVisionWithinIso],
for Dolby Vision profiles greater than 7.
Block type identifier: 0x68766345
Block type name: Dolby Vision enhancement-layer HEVC configuration
Description: the BlockAddIDExtraData
data is interpreted as the Dolby Vision enhancement-layer HEVC configuration as described in [@!DolbyVisionWithinIso].
This extension MUST NOT be used if Codec ID
is not V_MPEGH/ISO/HEVC
.
Block type identifier: 0x6D766343
Block type name: MVC configuration
Description: the BlockAddIDExtraData
data is interpreted as MVCDecoderConfigurationRecord
structure, as defined in [@!ISO.14496-15].
This extension MUST NOT be used if Codec ID
is not V_MPEG4/ISO/AVC
.