For chapters and tags only a subset of elements are allowed. mkvmerge(1) will automatically remove all elements not allowed by the specification.

The default language code is 'und' for 'undetermined'.

See the section about segment info XML files below for details.

If SID starts with = then its rest is interpreted as the name of a Matroska file whose segment UID is read and used.

Each file created contains one segment, and each segment has one segment UID. If more segment UIDs are specified than segments are created then the surplus UIDs are ignored. If fewer UIDs are specified than segments are created then random UIDs will be created for them.

This option can be used both for simple chapter files and for source files that contain chapters but no information about the chapters' language, e.g. MP4 and OGM files.

The language set with this option is also used when chapters are generated with the --generate-chapters option.

This switch does also apply to chapters that are copied from certain container types, e.g. Ogg/OGM and MP4 files. See the section about chapters below for details.

o/p: adjust the timestamps by o/p to fix linear drifts. p defaults to 1 if omitted. Both o and p can be floating point numbers.

Defaults: no manual sync correction (which is the same as d = 0 and o/p = 1.0).

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

The names for the new chapters are controlled by the option --generate-chapters-name-template. The language is set with --chapter-language which must occur before --generate-chapters.

There are several variables that can be used in the template that are replaced by their actual values when a chapter is generated. The string '<NUM>' will be replaced by the chapter number. The string '<START>' will be replaced by the chapter's start timestamp.

The strings '<FILE_NAME>' and '<FILE_NAME_WITH_EXT>' are only filled when generating chapters for appended files. They will be replaced by the appended file's name without respectively with its extension. Note that only the file's base name and extension are inserted, not its directory or drive components.

You can specify a minimum number of places for the chapter number with '<NUM:places>', e.g. '<NUM:3>'. The resulting number will be padded with leading zeroes if the number of places is less than specified.

You can control the format used by the start timestamp with <START:format>. The format defaults to '%H:%M:%S' if none is given. Valid format codes are:

If this option is not given then mkvmerge(1) defaults to the format '%p - %t' (the performer, followed by a space, a dash, another space and the title).

If the format is given then everything except the following meta characters is copied as-is, and the meta characters are replaced like this:

If no unit is used then mkvmerge(1) will put at most n data blocks into each cluster. The maximum number of blocks is 65535.

If the number d is postfixed with 'ms' then mkvmerge(1) puts at most d milliseconds of data into each cluster. The minimum for d is '100ms', and the maximum is '32000ms'.

mkvmerge(1) defaults to putting at most 65535 data blocks and 5000ms of data into a cluster.

Programs trying to find a certain frame can only seek directly to a cluster and have to read the whole cluster afterwards. Therefore creating larger clusters may lead to imprecise or slow seeking.

Normally mkvmerge(1) will use a value of 1000000 which means that timestamps and durations will have a precision of 1ms. For files that will not contain a video track but at least one audio track mkvmerge(1) will automatically chose a timestamp scale factor so that all timestamps and durations have a precision of one audio sample. This causes bigger overhead but allows precise seeking and extraction.

If the special value -1 is used then mkvmerge(1) will use sample precision even if a video track is present.

Enabling this option prevents mkvmerge(1) from writing those tags and from touching any existing tags with same names.

In the canonical form all subtags for which preferred values exist are replaced by those preferred values. This converts e.g. 'zh-yue-jyutping' to 'yue-jyutping' or 'fr-FX' to 'fr-FR'.

For the extended language subtags form the canonical form is built first. Afterwards all primary languages for which an extended language subtag exists are replaced by that extended language subtag and its prefix. This converts e.g. 'yue-jyutping' back to 'zh-yue-jyutping' but has no effect on 'fr-FR' as 'fr' is not an extended language subtag.

At the moment mkvmerge(1) supports the following modes:

For this splitting mode the output filename is treated differently than for the normal operation. It may contain a printf like expression '%d' including an optional field width, e.g. '%02d'. If it does then the current file number will be formatted appropriately and inserted at that point in the filename. If there is no such pattern then a pattern of '-%03d' is assumed right before the file's extension: '-o output.mkv' would result in 'output-001.mkv' and so on. If there's no extension then '-%03d' will be appended to the name.

Another possible pattern is '%c' which will be replaced by the name of the first chapter in the file. Note that when '%c' is present, the pattern '-%03d' will not be added automatically.

If SID starts with = then its rest is interpreted as the name of a Matroska file whose segment UID is read and used.

If SID starts with = then its rest is interpreted as the name of a Matroska file whose segment UID is read and used.

When mkvmerge appends a track (called 'track2_1' from now on) from a second file (called 'file2') to a track (called 'track1_1') from the first file (called 'file1') then it has to offset all timestamps for 'track2_1' by an amount. For 'file' mode this amount is the highest timestamp encountered in 'file1' even if that timestamp was from a different track than 'track1_1'. In track mode the offset is the highest timestamp of 'track1_1'.

Unfortunately mkvmerge cannot detect which mode to use reliably. Therefore it defaults to 'file' mode. 'file' mode usually works better for files that have been created independently of each other; e.g. when appending AVI or MP4 files. 'track' mode may work better for sources that are essentially just parts of one big file, e.g. for VOB and EVO files.

Subtitle tracks are always treated as if 'file' mode were active even if 'track' mode actually is.

If this option has been omitted then a standard mapping is used. This standard mapping appends each track from the current file to a track from the previous file with the same track ID. This allows for easy appending if a movie has been split into two parts and both file have the same number of tracks and track IDs with the command mkvmerge -o output.mkv part1.mkv +part2.mkv.

This is an alternative syntax to using '+' between the file names. Therefore the following two commands are equivalent:

$ mkvmerge -o full.mkv file1.mkv + file2.mkv
$ mkvmerge -o full.mkv '[' file1.mkv file2.mkv ']'

The '=' can also be put in front of the next file name. Therefore the following two commands are equivalent:

$ mkvmerge -o full.mkv = file1.vob
$ mkvmerge -o full.mkv =file1.vob

This can be used for e.g. VOB files coming from a DVD or MPEG transport streams. It cannot be used if each file contains its own set of headers which is usually the case with stand-alone files like AVI or MP4.

Putting a file name into parenthesis also prevents mkvmerge(1) from looking for additional files with the same base name as described in option =. Therefore these two command lines are equivalent:

$ mkvmerge -o out.mkv = file.mkv
$ mkvmerge -o out.mkv '(' file.mkv ')'

Several things should be noted:

If no MIME type is given a for an attachment, its type will be detected automatically.

mkvextract(1) can be used to extract attached files from a Matroska(TM) file.

This affects both new attachments if its MIME type is detected automatically and existing attachments whose stored MIME types will be remapped to the legacy ones.

The affected MIME types are 'font/sfnt', 'font/ttf' and 'font/collection' which are all mapped to 'application/x-truetype-fonts' and 'font/otf' which is mapped to 'application/vnd.ms-opentype'.

Instead of track IDs you can also provide ISO 639-2 language codes. This will only work for source files that provide language tags for their tracks.

Default: copy all tracks of this kind.

If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this kind but the ones listed after the !.

Instead of track IDs you can also provide ISO 639-2 language codes. This will only work for source files that provide language tags for their tracks.

If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this kind but the ones listed after the !.

Instead of track IDs you can also provide ISO 639-2 language codes. This will only work for source files that provide language tags for their tracks.

If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this kind but the ones listed after the !.

Instead of track IDs you can also provide ISO 639-2 language codes. This will only work for source files that provide language tags for their tracks.

If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this kind but the ones listed after the !.

If the IDs are prefixed with ! then the meaning is reversed: copy everything but the IDs listed after the !.

The default is to copy all attachments to all output files.

If the IDs are prefixed with ! then the meaning is reversed: copy everything but the IDs listed after the !.

o/p: adjust the timestamps by o/p to fix linear drifts. p defaults to 1 if omitted. Both o and p can be floating point numbers.

Defaults: no manual sync correction (which is the same as d = 0 and o/p = 1.0).

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

The default is 'iframes' for video and subtitle tracks and 'none' for audio tracks. See also option --no-cues which inhibits the creation of cue entries regardless of the --cues options used.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

If the user does not explicitly select a track during playback, the player should select one of the tracks that has its "default track" flag set, taking user preferences such as their preferred language into account.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

Only tracks whose "track enabled" flag is set should be considered for playback.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

If the source file is a Matroska(TM) file then the CodecID should be enough to detect SBR AAC. However, if the CodecID is wrong then this switch can be used to correct that.

If mkvmerge wrongfully detects that an AAC file is SBR then you can add ':0' to the track ID.

Currently only DTS tracks are affected by this option. TrueHD tracks that contain an embedded AC-3 core are instead presented as two separate tracks for which the user can select which track to copy. For DTS such a scheme would not work as the HD extensions cannot be decoded by themselves – unlike the TrueHD data.

Currently only AC-3, DTS and TrueHD tracks are affected by this option.

If the default duration is not forced then mkvmerge will try to derive the track's default duration from the container and/or the encoded bitstream for certain track types, e.g. AVC/H.264 or MPEG-2.

This option can also be used to change the FPS of video tracks without having to use an external timestamp file.

The compression method 'mpeg4_p2'/'mpeg4p2' is a special compression method called 'header removal' that is only available for MPEG4 part 2 video tracks.

The default for some subtitle types is 'zlib' compression. This compression method is also the one that most if not all playback applications support. Support for other compression methods other than 'none' is not assured.

Another way to specify the values is to use the --aspect-ratio or the --aspect-ratio-factor option (see below). These options are mutually exclusive.

Another way to specify the values is to use the --aspect-ratio-factor or --display-dimensions options (see above and below). These options are mutually exclusive.

Another way to specify the values is to use the --aspect-ratio or --display-dimensions options (see above). These options are mutually exclusive.

Valid values and their meaning are:

0: GBR, 1: BT709, 2: unspecified, 3: reserved, 4: FCC, 5: BT470BG, 6: SMPTE 170M, 7: SMPTE 240M, 8: YCOCG, 9: BT2020 non-constant luminance, 10: BT2020 constant luminance

Example: For video with 4:2:0 chroma subsampling, the parameter should be set to TID:1,1.

Example: For video with 4:2:1 chroma subsampling, the parameter --chroma-subsample should be set to TID:1,0 and Cb-subsample should be set to TID:1,0.

Valid values and their meaning are:

0: reserved, 1: ITU-R BT.709, 2: unspecified, 3: reserved, 4: gamma 2.2 curve, 5: gamma 2.8 curve, 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: SMPTE ST 2084, 17: SMPTE ST 428-1; 18: ARIB STD-B67 (HLG)

Valid values and their meaning are:

0: reserved, 1: ITU-R BT.709, 2: unspecified, 3: reserved, 4: ITU-R BT.470M, 5: ITU-R BT.470BG, 6: SMPTE 170M, 7: SMPTE 240M, 8: FILM, 9: ITU-R BT.2020, 10: SMPTE ST 428-1, 22: JEDEC P22 phosphors

0: progressive; 1: interlaced with top field displayed first and top field stored first; 2: undetermined field order; 6: interlaced with bottom field displayed first and bottom field stored first; 9: interlaced with bottom field displayed first and top field stored first; 14: interlaced with top field displayed first and bottom field stored first

'mono', 'side_by_side_left_first', 'top_bottom_right_first', 'top_bottom_left_first', 'checkerboard_right_first', 'checkerboard_left_first', 'row_interleaved_right_first', 'row_interleaved_left_first', 'column_interleaved_right_first', 'column_interleaved_left_first', 'anaglyph_cyan_red', 'side_by_side_right_first', 'anaglyph_green_magenta', 'both_eyes_laced_left_first', 'both_eyes_laced_right_first'.

This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

The output format used for the result can be changed with the option --identification-format.

If tracks are known to be present but not found then the percentage to probe can be changed with this option. The minimum of 10 MB is built-in and cannot be changed.

Selecting 'lowest' also causes mkvmerge(1) to select idle I/O priority in addition to the lowest possible process priority.

The seed can be an arbitrary string and does not have to be a number.

The result of byte-identical files is only guaranteed under the following conditions:

Using other versions of mkvmerge(1) or other command-line options may result in the same byte-identical file but is not guaranteed to do so.

$ mkvmerge -i v.mkv
File 'v.mkv': container: Matroska(TM)
Track ID 0: video (V_MS/VFW/FOURCC, DIV3)
Track ID 1: audio (A_MPEG/L3)

CHAPTER01=00:00:00.000
CHAPTER01NAME=Intro
CHAPTER02=00:02:30.000
CHAPTER02NAME=Baby prepares to rock
CHAPTER03=00:02:42.300
CHAPTER03NAME=Baby rocks the house

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE Chapters SYSTEM "matroskachapters.dtd">
<Chapters>
  <EditionEntry>
    <ChapterAtom>
      <ChapterTimeStart>00:00:30.000</ChapterTimeStart>
      <ChapterTimeEnd>00:01:20.000</ChapterTimeEnd>
      <ChapterDisplay>
        <ChapterString>A short chapter</ChapterString>
        <ChapterLanguage>eng</ChapterLanguage>
      </ChapterDisplay>
      <ChapterAtom>
        <ChapterTimeStart>00:00:46.000</ChapterTimeStart>
        <ChapterTimeEnd>00:01:10.000</ChapterTimeEnd>
        <ChapterDisplay>
          <ChapterString>A part of that short chapter</ChapterString>
          <ChapterLanguage>eng</ChapterLanguage>
        </ChapterDisplay>
      </ChapterAtom>
    </ChapterAtom>
  </EditionEntry>
</Chapters>

Chapters (master)
  EditionEntry (master)
    EditionUID (unsigned integer, valid range: 1 <= value)
    EditionFlagHidden (unsigned integer, valid range: 0 <= value <= 1)
    EditionFlagDefault (unsigned integer, valid range: 0 <= value <= 1)
    EditionFlagOrdered (unsigned integer, valid range: 0 <= value <= 1)
    ChapterAtom (master)
      ChapterAtom (master)
      ChapterUID (unsigned integer, valid range: 1 <= value)
      ChapterTimeStart (unsigned integer)
      ChapterTimeEnd (unsigned integer)
      ChapterFlagHidden (unsigned integer, valid range: 0 <= value <= 1)
      ChapterFlagEnabled (unsigned integer, valid range: 0 <= value <= 1)
      ChapterSegmentUID (binary, valid range: 1 <= length in bytes)
      ChapterSegmentEditionUID (unsigned integer, valid range: 1 <= value)
      ChapterPhysicalEquiv (unsigned integer)
      ChapterTrack (master)
        ChapterTrackNumber (unsigned integer, valid range: 1 <= value)
      ChapterDisplay (master)
        ChapterString (UTF-8 string)
        ChapterLanguage (UTF-8 string)
        ChapterCountry (UTF-8 string)
      ChapterProcess (master)
        ChapterProcessCodecID (unsigned integer)
        ChapterProcessPrivate (binary)
        ChapterProcessCommand (master)
          ChapterProcessTime (unsigned integer)
          ChapterProcessData (binary)

$ mkvmerge -o file.mkv --tags 0:tags.xml file.avi

Tags (master)
  Tag (master)
    Targets (master)
      TargetTypeValue (unsigned integer)
      TargetType (UTF-8 string)
      TrackUID (unsigned integer)
      EditionUID (unsigned integer)
      ChapterUID (unsigned integer)
      AttachmentUID (unsigned integer)
    Simple (master)
      Simple (master)
      Name (UTF-8 string)
      TagLanguage (UTF-8 string)
      DefaultLanguage (unsigned integer)
      String (UTF-8 string)
      Binary (binary)

# timestamp format v1
assume 27.930
800,1000,25
1500,1700,30

# timestamp format v2
0
40
80

# timestamp format v3
assume 0.0
25.325
7.530,38.236
gap, 10.050
2.000,38.236