MKVMERGE

NAME
SYNOPSIS
DESCRIPTION
USAGE
EXAMPLES
TRACK IDS
SUBTITLES
FILE LINKING
DEFAULT VALUES
ATTACHMENTS
CHAPTERS
TAGS
NOTES
AUTHOR
SEE ALSO
WWW

NAME

mkvmerge − Merge multimedia streams into a Matroska file

SYNOPSIS

mkvmerge [global options] −o out [options] <file1> [[options] <file2> ...] [@optionsfile]

DESCRIPTION

This program takes the input from several media files and joins their streams (all of them or just a selection) into a Matroska file. <http://www.matroska.org/>

Global options:

−v, −−verbose

Increase verbosity.

−q, −−quiet

Suppress status output.

−o, −−output out

Write to the file ’out’.

−−title <title>

Sets the general title for the output file, e.g. the movie name.

−−chapters <file>

Read chapter information from the file. See the section about chapters below for details.

−−global−tags <file>

Read global tags from the XML file. See the section about tags below for details.

General output control (still global, advanced options):

−−cluster−length n[ms]

Put at most n data blocks into each cluster. If the number is postfixed with ’ms’ then put at most n milliseconds of data into each cluster. The maximum length for a cluster is 65535ms. Programs will only be able to seek to clusters, so creating larger clusters may lead to imprecise seeking and/or processing.

−−no−cues

Tells mkvmerge not to create and write the cue data which can be compared to an index in an AVI. Matroska files can be played back without the cue data, but seeking will probably be imprecise and slower. Use this only if you’re really desperate for space or for testing purposes. See also option −−cues which can be specified for each input file.

−−no−meta−seek

The meta seek information is stored along with the headers at the beginning of the file and points to the cue entries (the index). This allows a player to quickly find the index and uses very little space. It should be left on and only disabled for testing purposes. At the moment −−no−cues implies −−no−meta−seek.

−−meta−seek−size d

Reserve d bytes for the meta seek information (see −−no−meta−seek). Default value is 100 bytes which should be enough. mkvmerge will abort with an appropriate warning message if the space is not enough and also provide the optimal size to use with this option. This option is normally not needed.

−−no−lacing

Disable lacing for all tracks. This will increase the file’s size, especially if there are many audio tracks. This option is not intended for everyday use.

File splitting and linking (still global):

−−split <d[k|m|g]> or −−split <HH:MM:SS|ns>

Splits the output file after a given size or a given time. For splitting after a specific size the parameter d may end with k, m or g to indicate that the size is in KB, MB or GB respectively. For time-based splitting use the form HH:MM:SS or add ’s’ to the number of seconds n after which the file should be split.
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.

−−split−max−files <n>

Create at most n files, even if the last file will be longer or larger than indicated by −−split.

−−dont−link

Do not link files to one another when splitting the output file. See the section FILE LINKING below for details.

−−link−to−previous <UID>

Links the first output file to the segment with the given UID. See the section FILE LINKING below for details.

−−link−to−next <UID>

Links the last output file to the segment with the given UID. See the section FILE LINKING below for details.

Attachment support (still global):

−−attachment−description <description>

Plain text description of the following attachment. Applies to the next −−attach−file or −−attach−file−once command.

−−attachment−mime−type <MIME type>

MIME type of the following attachment. Applies to the next −−attach−file or −−attach−file−once command. A list of officially recognized MIME types can be found e.g. at <ftp://ftp.isi.edu/in-notes/iana/assignments/media-types/media-types> The MIME type is mandatory for an attachment.

−−attach−file <file name>

−−attach−file−once <file name>

Creates a file attachment inside the Matroska file. The MIME type must have been set before this option can used. The difference between the two forms is that during splitting the files attached with −−attach−file are attached to all output files while the ones attached with −−attach−file−once are only attached to the first file created. If splitting is not used then both do the same.
mkvextract
can be used to extract attached files from a Matroska file.
Note:
If an input file is a Matroska file then the attached files will not be copied to the output file(s). This may change in the future.

Options that can be used for each input file:

−a, −−atracks <n,m,...>

Copy the audio tracks n, m etc. The numbers are track IDs which can be obtained with the −−identify switch. They’re not simply the track numbers (see section TRACK IDS). Default: copy all audio tracks.

−d, −−vtracks <n,m,...>

Copy the video tracks n, m etc. The numbers are track IDs which can be obtained with the −−identify switch (see section TRACK IDS). They’re not simply the track numbers. Default: copy all video tracks.

−s, −−stracks <n,m,...>

Copy the subtitle tracks n, m etc. The numbers are track IDs which can be obtained with the −−identify switch (see section TRACK IDS). They’re not simply the track numbers. Default: copy all subtitle tracks.

−A, −−noaudio

Don’t copy any audio track from this file.

−D, −−novideo

Don’t copy any video track from this file.

−T, −−nosubs

Don’t copy any subtitle track from this file.

−y, −−sync <TID:d[,o[/p]]>

Synchronize manually, delay the audio track with the id TID by d ms. The track IDs are the same as the ones given with −−identify (see section TRACK IDS).
d
> 0: Pad with silent samples.
d
< 0: Remove samples from the beginning.
o
/p: adjust the timestamps by o/p to fix linear drifts. p defaults to 1000 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.

−−cues <TID:none|iframes|all>

Controls for which tracks cue (index) entries are created for the given track (see section TRACK IDS). none inhibits the creation of cue entries. For iframes only blocks with no backward or forward references ( = I frames in video tracks) are put into the cue sheet. all causes mkvmerge to create cue entries for all blocks which will make the file very big.
The default is iframes for video tracks and none for all others. 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.

−−default−track <TID>

Sets the ’default’ flag for the given track (see section TRACK IDS). If the user does not explicitly select a track himself then the player should prefer the track that has his ’default’ flag set. Only one track of each kind (audio, video, subtitles) can have his ’default’ flag set.
This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

−−language <TID:language>

Sets the language for the given track (see section TRACK IDS). Only ISO639-2 codes are allowed. All languages including their ISO639-2 codes can be listed with the −−list−languages option.
This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

−t, −−tags <TID:file>

Read tags for the track with the number TID from the file. See the section about tags below for details.

Options that only apply to video tracks:

−f, −−fourcc <FourCC>

Forces the FourCC to the specified value. Works only for video tracks.

−−aspect−ratio <ar|w/h>

Sets the aspect ratio for the track. The ratio can be given either as a floating point number or as ’width/height’, e.g. 16/9.

Options that only apply to subtitle tracks:

−−sub−charset <TID:charset>

Sets the charset for the conversion to UTF-8 for UTF-8 subtitles for the given track ID. If not specified the charset will be derived from the current locale settings. Note that a charset is not needed for subtitles read from Matroska files as these are always stored in UTF-8.
This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.

Other options:

−i, −−identify <filename>

Will let mkvmerge probe the single file and report its type, the tracks contained in the file and their track IDs. If this option is used then the only other option allowed is the filename.

−l, −−list−types

Lists supported input file types.

−−list−languages

Lists all languages and their ISO639-2 code which can be used with the −−language option.

−h, −−help

Show usage information.

−V, −−version

Show version information.

@optionsfile

Reads additional command line arguments from the file optionsfile. Lines whose first non-whitespace character is a hash mark (#) are treated as comments and ignored. White spaces at the start and end of a line will be stripped. If a space is encountered and the line starts with ’−’ then the line will be split into exactly two arguments - the string before the space and the string after it. There is no meta character escaping.
The command line mkvmerge −o "my file.mkv" -A "a movie.avi" sound.ogg could be converted into the following option file:
# Write to the file "my file.mkv".
−o my file.mkv
# Only take the video from "a movie.avi".
−A a movie.avi
sound.ogg

USAGE

For each file the user can select which tracks mkvmerge should take. They are all put into the file specified with ’-o’. A list of known (and supported) source formats can be obtained with the ’-l’ option.

EXAMPLES

Let’s assume you have a file called MyMovie.avi and the audio track in a separate file, e.g. MyMovie.wav. First you want to encode the audio to OGG:

$ oggenc -q4 -oMyMovie.ogg MyMovie.wav

After a couple of minutes you can join video and audio:

$ mkvmerge -o MyMovie-with-sound.mkv MyMovie.avi MyMovie.ogg

If your AVI already contains an audio track then it will be copied as well (if mkvmerge supports the audio format). To avoid that simply do

$ mkvmerge -o MyMovie-with-sound.mkv -A MyMovie.avi MyMovie.ogg

After some minutes of consideration you rip another audio track, e.g. the director’s comments or another language to MyMovie-add-audio.wav. Encode it again and join it up with the other file:

$ oggenc -q4 -oMyMovie-add-audio.ogg MyMovie-add-audio.wav
$ mkvmerge -o MM-complete.mkv MyMovie-with-sound.mkv MyMovie-add-audio.ogg

The same result can be achieved with

$ mkvmerge -o MM-complete.mkv -A MyMovie.avi MyMovie.ogg \
MyMovie-add-audio.ogg

Now fire up mplayer and enjoy. If you have multiple audio tracks (or even video tracks) then you can tell mplayer which track to play with the ’-vid’ and ’-aid’ parameters. These are 0-based and do not distinguish between video and audio.

If you need an audio track synchronized you can do that easily. First find out which track ID the Vorbis track has with

$ mkvmerge --identify outofsync.ogg

Now you can use that ID in the following command line:

$ mkvmerge -o goodsync.mkv -A source.avi -y 12345:200 outofsync.ogg

This would add 200ms of silence at the beginning of the audio track with the ID 12345 taken from outofsync.ogg.

Some movies start synced correctly but slowly drift out of sync. For these kind of movies you can specify a delay factor that is applied to all timestamps - no data is added or removed. So if you make that factor too big or too small you’ll get bad results. An example is that an episode I transcoded was 0.2 seconds out of sync at the end of the movie which was 77340 frames long. At 29.97fps 0.2 seconds correspond to approx. 6 frames. So I did

$ mkvmerge -o goodsync.mkv -y 23456:0,77346/77340 outofsync.mkv

The result was fine.

The sync options can also be used for subtitles in the same manner.

For text subtitles you can either use some Windows software (like SubRipper) or the subrip package found in transcode(1)’s sources (in contrib/subrip). The general process is:

1.

extract a raw subtitle stream from the source:

$ tccat -i /path/to/copied/dvd/ -T 1 -L | \
tcextract -x ps1 -t vob -a 0x20 | \
subtitle2pgm -o mymovie

2.

convert the resulting PGM images to text with gocr:

$ pgm2txt mymovie

3.

spell-check the resulting text files:

$ ispell -d american *txt

4.

convert the text files to a SRT file:

$ srttool -s -w -i mymovie.srtx -o mymovie.srt

The resulting file can be used as another input file for mkvmerge:

$ mkvmerge -o mymovie.mkv mymovie.avi mymovie.srt

If you want to specify the language for a given track then this is easily done. First find out the ISO639-2 code for your language. mkvmerge can list all of those codes for you:

$ mkvmerge --list-languages

Search the list for the languages you need. Let’s assume you have put two audio tracks into a Matroska file and want to set their language codes and that their track IDs are 2 and 3. This can be done with

$ mkvmerge -o with-lang-codes.mkv --language 2:ger --language 3:dut without-lang-codes.mkv

As you can see you can use the --language switch multiple times.

Maybe you’d also like to have the player use the Dutch language as the default language. You also have extra subtitles, e.g. in English and French, and want to have the player display the French ones by default. This can be done with

$ mkvmerge -o with-lang-codes.mkv --language 2:ger --language 3:dut --default-track 3 without-lang-codes.mkv --language 0:eng english.srt --default-track 0 --language 0:fre french.srt

If you do not see the language or default track flags that you’ve specified in mkvinfo’s output then please read the section about DEFAULT VALUES.

TRACK IDS

Some of the options for mkvmerge need a track ID to specify which track they should be applied to. Those track IDs are printed by the readers when demuxing the current input file, or if mkvmerge is called with the −−identify option. Track IDs are assigned like this:

*

AVI files: The video track has the ID 0. All audio tracks get the ID 1, 2...

*

AAC, AC3, MP3, SRT and WAV files: The one ’track’ in that file gets the ID 0.

*

Ogg/OGM files: The track’s ID is its serial number as given in the Ogg stream header page.

*

Matroska files: The track’s ID is the track number as reported by mkvinfo or mkvmerge −−identify. It is not the track UID.

The special track ID ’-1’ is a wild card and applies the given switch to all tracks that are read from an input file. This was the behaviour of these switches prior to version 0.4.4.

The options that use the track IDs are: −−atracks, −−vtracks, −−stracks, −−sync, −−default-track, −−cues and −−language.

SUBTITLES

There are several text subtitle formats that can be embedded into Matroska. At the moment mkvmerge supports only text subtitle formats. These subtitles must be recoded to UTF-8 so that they can be displayed correctly by a player.

mkvmerge does this conversion automatically based on the system’s current locale. If the subtitle charset is not the same as the system’s current charset then the user can use −−sub−charset switch. If the subtitles are already encoded in UTF-8 then you can use −−sub−charset UTF−8.

The following subtitle formats are supported at the moment:

*

Subtitle Ripper (SRT) files

*

Substation Alpha (SSA) / Advanced Substation Alpha scripts (ASS)

FILE LINKING

Matroska supports file linking which simply says that a specific file is the predecessor or successor of the current file. To be precise, it’s not really the files that are linked but the Matroska segments. As most files will probably only contain one Matroska segment I simply say ’file linking’ although ’segment linking’ would be more appropriate.

Each segment is identified by a unique 128 bit wide segment UID. This UID is automatically generated by mkvmerge. The linking is done primarily via putting the segment UIDs of the previous/next file into the segment header information. mkvinfo(1) prints these UIDs if it finds them.

If a file is split into several smaller ones and linking is used then the timecodes will not start at 0 again but will continue where the last file has left off. This way the absolute time is kept even if the previous files are not available (e.g. when streaming). If no linking is used then the timecodes should start at 0 for each file. By default mkvmerge uses file linking. If you don’t want that you can turn it off with the ´−−dont−link´ option. This option is only useful if splitting is activated as well.

Regardless of whether splitting is active or not the user can tell mkvmerge to link the produced files to specific UIDs. This is achieved with the options ’−−link−to−previous’ and ’−−link−to−next’. These options accept a segment UID in the format that mkvinfo(1) outputs: 16 hexadecimal numbers between 0x00 and 0xff prefixed with ’0x’ each, e.g. 0x41 0xda 0x73 0x66 0xd9 0xcf 0xb2 0x1e 0xae 0x78 0xeb 0xb4 0x5e 0xca 0xb3 0x93. Alternatively a shorter form can be used: 16 hexadecimal numbers between 0x00 and 0xff without the ’0x’ prefixes and without the spaces, e.g. 41da7366d9cfb21eae78ebb45ecab393.

If splitting is used then the first file is linked to the UID given with ´−−link−to−previous´ and the last file is linked to the UID given with ´−−link−to−next´. If splitting is not used then the one output file will be linked to both of the two UIDs.

DEFAULT VALUES

The Matroska specs say that some elements have a default value. Usually an element is not written to the file if its value is equal to its default value in order to save space. The elements that the user might miss in mkvinfo’s output are the language and the default track flag. The default value for the language is English (eng), and the default value for the default track flag is true. Therefore if you used --language 0:eng for a track then it will not show up in mkvinfo’s output.

ATTACHMENTS

Maybe you also want to keep some photos along with your Matroska file, or you’re using SSA subtitles and need a special TrueType font that’s really rare. In these cases you can attach those files to the Matroska file. They will not be just appended to the file but embedded in it. A player can then show those files (the ’photos’ case) or use them to render the subtitles (the ’TrueType fonts’ case).

Here’s an example how to attach a photo and a TrueType font to the output file:
$ mkvmerge -o output.mkv -A video.avi sound.ogg −−attachment−description "Me and the band behind the stage in a small get-together" −−attachment−mime−type image/jpeg −−attach−file me_and_the_band.jpg −−attachment−description "The real rare and unbelievably good looking font" −−attachment−type application/octet−stream −−attach−file really_cool_font.ttf

CHAPTERS

The Matroska chapter system is more powerful than the old known system used by OGMs. The full specs can be found at <http://cvs.corecodec.org/cgi-bin/viewcvs.cgi/*checkout*/matroska/doc/website/technical/specs/chapters/index.html>

mkvmerge’s chapter support is still a bit limited, though. At the moment it only supports reading chapter data in the same format that the OGM tools expect. It looks basically like this:

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

mkvmerge will transform every pair or lines (CHAPTERxx and CHAPTERxxNAME) into one Matroska ChapterAtom. It does not set any ChapterTrackNumber which means that the chapters all apply to all tracks in the file.

When splitting files mkvmerge will correctly adjust the chapters as well. This means that each file only includes the chapter entries that apply to it, and that the timecodes will be offset to match the new timecodes of each output file.

Another shortcoming is that mkvmerge will silently discards chapters found in source files - e.g. when reading them from an OGM file or another Matroska file. You can use mkvextract to export chapters from another Matroska file and use the result with mkvmerge.

The upcoming version of mkvmerge will address most of the shortcomings mentioned above.

TAGS

Introduction

Matroska supports an extensive set of tags. Unlike other containers/formats it does not rely on a free form specification of the type KEY=VALUE but provides a big number of tags that are a subset of several well-known tagging schemes unified in one big tag tree. The full specification can be found at <http://cvs.corecodec.org/cgi-bin/viewcvs.cgi/*checkout*/matroska/doc/website/technical/specs/tagging/index.html>

Scope of the tags

Matroska tags do not automatically apply to the complete file. They may, however, apply to different parts of the file: to one or more tracks, to one or more chapters, or even to a combination of both. The aforementioned URL gives more details about this fact.

One important fact is that tags are linked to tracks or chapters with the Targets Matroska tag element, and that the UIDs used for this linking are NOT the track IDs mkvmerge uses everywhere. Instead the numbers used are the UIDs which mkvmerge calculates automatically (if the track is taken from a file format other than Matroska) or which are copied from the source file if the track’s source file is a Matroska file. Therefore it is difficult to know which UIDs to use in the tag file before the file is handed over to mkvmerge.

mkvmerge knows two options with which you can add tags to Matroska files: The −−global−tags and the −−tags options. The difference is that the former option, −−global−tags, will not modify the tags read from the file in any way, while the latter option, −−tags, automatically inserts the UID that mkvmerge generates for the tag specified with the TID part of the −−tags option. Therefore the tag file used with −−tags does not need any Targets element (in fact they are deleted if the tag file contained any), while the one used with −−global−tags does need them.

Example

Let’s say that you want to add tags to a video track read from an AVI. mkvmerge -i file.avi tells you that the video track’s ID (do not mix this ID with the UID!) is 0. So you create your tag file, leave out any Targets element and call mkvmerge:
$ mkvmerge -o file.mkv --tags 0:tags.xml file.avi

Tag file format

mkvmerge supports a XML based tag file format. The format is very easy and closely connected to the Matroska tag specs found at the URL mentioned above. Both the binary and the source mkvtoolnix distributions come with a sample file called matroska-tags.xml which simply lists all known tags and which can be used as a basis for real life tag files.

The basics are:

*

The outermost element must be <Tags>.

*

One logical tag is contained inside one pair of <Tag> XML tags.

*

White spaces directly before and after tag contents are ignored.

Data types

The data type expected can be found in the official Matroska tag specs. The types integer, unsigned integer, float, string and UTF-8 string look just like you expect them to: 4254, -2, 5.0, hello world and hello world. Two data types are treadet differently, however: binary and date.

As binary data itself would not fit into a XML file mkvmerge supports two other methods of storing binary data. If the contents of a XML tag starts with ’@’ then the following text is treated as a file name. The corresponding file’s content is copied into the Matroska element.

Otherwise the data is expected to be Base64 encoded. This is an encoding that transforms binary data into a limited set of ASCII characters and is used e.g. in email programs. mkvtoolnix comes with a utility, base64tool, that can be used to encode to and decode from Base64. mkvextract will output Base64 encoded data for binary elements.

The date format used by both mkvmerge when reading XML tag files and by mkvextract when outputting XML tag data is the ISO-8601 format. It has the following structure: YYYY-MM-DDTHH:MM:SS+TZTZ. YYYY is the year (four digist long), MM the month (two digits long starting with 01), DD the day of the month (two digits long starting with 01), HH the hour of the day (two digits long, range 00 - 23), MM the minute (two digits long, range 00 - 59), SS the seconds (two digits long, range 00 - 59). +TZTZ is the time zone, e.g. +0100 or -0200. An example would be 2003-07-30T19:10:16+0200.

NOTES

What works:

*

AVI as the video and audio source (only raw PCM, MP3 and AC3 audio tracks at the moment)

*

OGG as the source for video, audio (Vorbis, raw PCM, MP3 and AC3 audio) and text streams (subtitles).

*

WAV as the audio source

*

AAC audio files (only those with ADTS headers before each packet)

*

AC3 audio files

*

DTS audio files

*

MP3 audio files

*

RealVideo and RealAudio from RealMedia files

*

Track selection

*

Manual audio synchronization by adding silence/removing packets for Vorbis audio and for text streams by adjusting the starting point and duration.

*

Manual audio synchronization for AAC, AC3, DTS and MP3 audio by duplicating or removing packets at the beginning.

*

Text subtitles can be read from SRT (SubRipper / subrip) files or taken from other OGM files.

*

SSA/ASS subtitles from SSA/ASS files

*

Simple chapters.

*

Full tags support.

What not works:

*

Manual audio synchronization for PCM sound (who needs it anyway?)

AUTHOR

mkvmerge was written by Moritz Bunkus <moritz@bunkus.org>.

SEE ALSO

mkvinfo(1), mkvextract(1)

WWW

The newest version can always be found at <http://www.bunkus.org/videotools/mkvtoolnix/>