<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"
[
<!ENTITY product "mkvmerge">
<!ENTITY version "10.0.0">
<!ENTITY date "2017-03-25">

<!ENTITY mkvmerge "<citerefentry><refentrytitle>mkvmerge</refentrytitle><manvolnum>1</manvolnum></citerefentry>">
<!ENTITY mkvinfo "<citerefentry><refentrytitle>mkvinfo</refentrytitle><manvolnum>1</manvolnum></citerefentry>">
<!ENTITY mkvextract "<citerefentry><refentrytitle>mkvextract</refentrytitle><manvolnum>1</manvolnum></citerefentry>">
<!ENTITY mkvpropedit "<citerefentry><refentrytitle>mkvpropedit</refentrytitle><manvolnum>1</manvolnum></citerefentry>">
<!ENTITY mtxgui "<citerefentry><refentrytitle>mkvtoolnix-gui</refentrytitle><manvolnum>1</manvolnum></citerefentry>">

<!ENTITY matroska "<productname>Matroska</productname>">
<!ENTITY oggvorbis "<productname>OggVorbis</productname>">
<!ENTITY xml "<abbrev>XML</abbrev>">

]>

<refentry lang="en" id="mkvmerge">
 <refentryinfo>
  <productname>&product;</productname>
  <date>&date;</date>
  <authorgroup>
   <author>
    <contrib>Developer</contrib>
    <firstname>Moritz</firstname>
    <surname>Bunkus</surname>
    <email>moritz@bunkus.org</email>
   </author>
  </authorgroup>
 </refentryinfo>
 <refmeta>
  <refentrytitle>&product;</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="version">&version;</refmiscinfo>
  <refmiscinfo class="date">&date;</refmiscinfo>
  <refmiscinfo class="source">MKVToolNix</refmiscinfo>
  <refmiscinfo class="manual">User Commands</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>&product;</refname>
  <refpurpose>Merge multimedia streams into a &matroska; file</refpurpose>
 </refnamediv>

 <refsynopsisdiv id="mkvmerge.synopsis">
  <title>Synopsis</title>
  <cmdsynopsis>
   <command>mkvmerge</command>
   <arg>global options</arg>
   <arg choice="req">-o out</arg>
   <arg>options1</arg>
   <arg choice="req">file1</arg>
   <arg>
    <arg>options2</arg>
    <arg choice="req">file2</arg>
   </arg>
   <arg>@options-file.json</arg>
  </cmdsynopsis>
 </refsynopsisdiv>

 <refsect1 id="mkvmerge.description">
  <title>Description</title>
  <para>
   This program takes the input from several media files and joins their streams (all of them or just a selection) into
   a &matroska; file; see <ulink url="http://www.matroska.org/">the &matroska; website</ulink>.
  </para>

  <important>
   <para>
    The order of command line options is important. Please read the section <link linkend="mkvmerge.option_order">&quot;Option
    order&quot;</link> if you're new to the program.
   </para>
  </important>

  <refsect2>
   <title>Global options</title>

   <variablelist>
    <varlistentry>
     <term><option>-v</option>, <option>--verbose</option></term>
     <listitem>
      <para>Increase verbosity.</para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-q</option>, <option>--quiet</option></term>
     <listitem>
      <para>Suppress status output.</para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-o</option>, <option>--output</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>Write to the file <parameter>file-name</parameter>.  If splitting is used then this parameter is treated a bit differently.  See
      the explanation for the <link linkend="mkvmerge.description.split"><option>--split</option></link> option for details.</para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-w</option>, <option>--webm</option></term>
     <listitem>
      <para>Create a WebM compliant file. This is also turned on if the output file name's extension is &quot;webm&quot;. This mode enforces
      several restrictions. The only allowed codecs are VP8, VP9 video and Opus, Vorbis audio tracks. Neither chapters nor tags are
      allowed. The DocType header item is changed to &quot;webm&quot;.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.title">
     <term><option>--title</option> <parameter>title</parameter></term>
     <listitem>
      <para>Sets the general title for the output file, e.g. the movie name.</para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--default-language</option> <parameter>language-code</parameter></term>
     <listitem>
      <para>Sets the default language code that will be used for tracks for which no language is set with the <link
      linkend="mkvmerge.description.language"><option>--language</option></link> option and for which the source container doesn't provide a
      language.</para>

      <para>The default language code is '<literal>und</literal>' for 'undefined'.</para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Segment info handling (global options)</title>

   <variablelist>
    <varlistentry>
     <term><option>--segmentinfo</option> <parameter>filename.xml</parameter></term>
     <listitem>
      <para>
       Read segment information from a <abbrev>XML</abbrev> file. This file can contain the segment family <abbrev>UID</abbrev>, segment
       <abbrev>UID</abbrev>, previous and next segment <abbrev>UID</abbrev> elements. An example file and a <abbrev>DTD</abbrev> are included
       in the MKVToolNix distribution.
      </para>

      <para>
       See the section about <link linkend="mkvmerge.segmentinfo">segment info XML files</link> below for details.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--segment-uid</option> <parameter>SID1,SID2,...</parameter></term>
     <listitem>
      <para>
       Sets the segment UIDs to use. This is a comma-separated list of 128bit segment UIDs in the usual UID form: hex numbers with or without
       the &quot;0x&quot; prefix, with or without spaces, exactly 32 digits.
      </para>

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

      <para>
       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.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Chapter and tag handling (global options)</title>

   <variablelist>
    <varlistentry id="mkvmerge.description.chapter_language">
     <term><option>--chapter-language</option> <parameter>language-code</parameter></term>
     <listitem>
      <para>
       Sets the ISO639-2 language code that is written for each chapter entry.  Defaults to '<literal>eng</literal>'.  See the section about
       <link linkend="mkvmerge.chapters">chapters</link> below for details.
      </para>

      <para>
       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.
      </para>

      <para>
       The language set with this option is also used when chapters are generated with the <link
       linkend="mkvmerge.description.generate_chapters"><option>--generate-chapters</option> option</link>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.chapter_charset">
     <term><option>--chapter-charset</option> <parameter>character-set</parameter></term>
     <listitem>
      <para>
       Sets the character set that is used for the conversion to UTF-8 for simple chapter files. See the section about <link
       linkend="mkvmerge.text_files_and_charsets"> text files and character sets</link> for an explanation how &mkvmerge; converts between
       character sets.
      </para>

      <para>
       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.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.generate_chapters">
     <term><option>--generate-chapters</option> <parameter>mode</parameter></term>
     <listitem>
      <para>
       &mkvmerge; can create chapters automatically.  The following two modes are currently supported:
      </para>

      <itemizedlist>
       <listitem>
        <para>
         '<literal>when-appending</literal>' – This mode creates one chapter at the start and one chapter whenever a file is appended.
        </para>

        <note>
         <para>
          &mkvmerge; requires a video or an audio track to be present in order to be able to determine when a new file is appended.  If one or
          more video tracks are muxed the first one is used.  Otherwise the first audio track is used.
         </para>
        </note>
       </listitem>

       <listitem>
        <para>
         '<literal>interval:</literal><parameter>time-spec</parameter>' – This mode creates one chapter at fixed intervals given by
         <parameter>time-spec</parameter>.  The format is either the form <parameter>HH:MM:SS.nnnnnnnnn</parameter> or a number followed by
         one of the units '<literal>s</literal>', '<literal>ms</literal>' or '<literal>us</literal>'.
        </para>

        <para>
         Example: <literal>--generate-chapters interval:45s</literal>
        </para>
       </listitem>
      </itemizedlist>

      <para>
       The names for the new chapters are controlled by the option <link
       linkend="mkvmerge.description.generate_chapters_name_template">--generate-chapters-name-template</link>.  The language is set with
       <link linkend="mkvmerge.description.chapter_language">--chapter-language</link> which must occur before
       <option>--generate-chapters</option>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.generate_chapters_name_template">
     <term><option>--generate-chapters-name-template</option> <parameter>template</parameter></term>
     <listitem>
      <para>
       This sets the name template for chapter names generated by the option <link
       linkend="mkvmerge.description.generate_chapters">--generate-chapters</link>. If the option is not used then default '<literal>Chapter
       &lt;NUM:2&gt;</literal>' will be used.
      </para>

      <para>
       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 '<literal>&lt;NUM&gt;</literal>' will be replaced by the chapter number. The string '<literal>&lt;START&gt;</literal>'
       will be replaced by the chapter's start timestamp.
      </para>

      <para>
       The strings <literal>'&lt;FILE_NAME&gt;'</literal> and <literal>'&lt;FILE_NAME_WITH_EXT&gt;'</literal> are only filled when
       generating chapters for appended files.  They will be replaced by the appended file's name wihtout respectively with its extension.
       Note that only the file's base name and extension are inserted, not its directory or drive components.
      </para>

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

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

      <itemizedlist>
       <listitem>
        <para><literal>%h</literal> – hours</para>
       </listitem>
       <listitem>
        <para><literal>%H</literal> – hours zero-padded to two places</para>
       </listitem>
       <listitem>
        <para><literal>%m</literal> – minutes</para>
       </listitem>
       <listitem>
        <para><literal>%M</literal> – minutes zero-padded to two places</para>
       </listitem>
       <listitem>
        <para><literal>%s</literal> – seconds</para>
       </listitem>
       <listitem>
        <para><literal>%S</literal> – seconds zero-padded to two places</para>
       </listitem>
       <listitem>
        <para><literal>%n</literal> – nanoseconds with nine places</para>
       </listitem>
       <listitem>
        <para><literal>%&lt;1-9&gt;n</literal> – nanoseconds with up to nine places (e.g. three places with <literal>%3n</literal>)</para>
       </listitem>
      </itemizedlist>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--cue-chapter-name-format</option> <parameter>format</parameter></term>
     <listitem>
      <para>
       &mkvmerge; supports reading <abbrev>CUE</abbrev> sheets for audio files as the input for chapters. <abbrev>CUE</abbrev> sheets usually
       contain the entries <varname>PERFORMER</varname> and <varname>TITLE</varname> for each index entry. &mkvmerge; uses these two strings
       in order to construct the chapter name. With this option the format used for this name can be set.
      </para>

      <para>
       If this option is not given then &mkvmerge; defaults to the format '<code>%p - %t</code>' (the performer, followed by a space, a dash,
       another space and the title).
      </para>

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

      <itemizedlist>
       <listitem>
        <para><parameter>%p</parameter> is replaced by the current entry's <varname>PERFORMER</varname> string,</para>
       </listitem>
       <listitem>
        <para><parameter>%t</parameter> is replaced by the current entry's <varname>TITLE</varname> string,</para>
       </listitem>
       <listitem>
        <para><parameter>%n</parameter> is replaced by the current track number and</para>
       </listitem>
       <listitem>
        <para><parameter>%N</parameter> is replaced by the current track number padded with a leading zero if
        it is &lt; 10.</para>
       </listitem>
      </itemizedlist>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chapters</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       Read chapter information from the file <parameter>file-name</parameter>. See the section about <link
       linkend="mkvmerge.chapters">chapters</link> below for details.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.global_tags">
     <term><option>--global-tags</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       Read global tags from the file <parameter>file-name</parameter>. See the section about <link linkend="mkvmerge.tags">tags</link> below
       for details.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>General output control (advanced global options)</title>

   <variablelist>
    <varlistentry>
     <term><option>--track-order</option> <parameter>FID1:TID1,FID2:TID2,...</parameter></term>
     <listitem>
      <para>
       This option changes the order in which the tracks for an input file are created. The argument is a comma separated list of pairs
       IDs. Each pair contains first the file ID (<parameter>FID1</parameter>) which is simply the number of the file on the command line
       starting at 0. The second is a track ID (<parameter>TID1</parameter>) from that file.  If some track IDs are omitted then those tracks
       are created after the ones given with this option have been created.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--cluster-length</option> <parameter>spec</parameter></term>
     <listitem>
      <para>
       Limit the number of data blocks or the duration of data in each cluster. The <parameter>spec</parameter> parameter can either be a
       number <parameter>n</parameter> without a unit or a number <parameter>d</parameter> postfixed with '<literal>ms</literal>'.
      </para>

      <para>
       If no unit is used then &mkvmerge; will put at most <parameter>n</parameter> data blocks into each cluster. The maximum number of
       blocks is 65535.
      </para>

      <para>
       If the number <parameter>d</parameter> is postfixed with '<literal>ms</literal>' then &mkvmerge; puts at most <parameter>d</parameter>
       milliseconds of data into each cluster. The minimum for <parameter>d</parameter> is '<literal>100ms</literal>', and the maximum is
       '<literal>32000ms</literal>'.
      </para>

      <para>
       &mkvmerge; defaults to putting at most 65535 data blocks and 5000ms of data into a cluster.
      </para>

      <para>
       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.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.no_cues">
     <term><option>--no-cues</option></term>
     <listitem>
      <para>
       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 <link linkend="mkvmerge.description.cues"><option>--cues</option></link> which can be specified for
       each input file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--clusters-in-meta-seek</option></term>
     <listitem>
      <para>
       Tells &mkvmerge; to create a meta seek element at the end of the file containing all clusters. See also the section about the
       <link linkend="mkvmerge.file_layout">&matroska; file layout</link>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--disable-lacing</option></term>
     <listitem>
      <para>
       Disables 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.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--enable-durations</option></term>
     <listitem>
      <para>
       Write durations for all blocks. This will increase file size and does not offer any additional value for players at the moment.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--disable-track-statistics-tags</option></term>
     <listitem>
      <para>
       Normally &mkvmerge; will write certain tags with statistics for each track. If such tags are already present then they will be
       overwritten. The tags are <constant>BPS</constant>, <constant>DURATION</constant>, <constant>NUMBER_OF_BYTES</constant> and
       <constant>NUMBER_OF_FRAMES</constant>.
      </para>

      <para>
       Enabling this option prevents &mkvmerge; from writing those tags and from touching any existing tags with same names.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.timecode_scale">
     <term><option>--timecode-scale</option> <parameter>factor</parameter></term>
     <listitem>
      <para>
       Forces the timecode scale factor to <parameter>factor</parameter>. Valid values are in the range
       <constant>1000</constant>..<constant>10000000</constant> or the special value <constant>-1</constant>.
      </para>

      <para>
       Normally &mkvmerge; will use a value of <constant>1000000</constant> which means that timecodes and durations will have a precision of
       1ms. For files that will not contain a video track but at least one audio track &mkvmerge; will automatically chose a timecode scale
       factor so that all timecodes and durations have a precision of one audio sample. This causes bigger overhead but allows precise
       seeking and extraction.
      </para>

      <para>
       If the special value <constant>-1</constant> is used then &mkvmerge; will use sample precision even if a video track is present.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>File splitting, linking, appending and concatenation (more global options)</title>

   <variablelist>
    <varlistentry id="mkvmerge.description.split">
     <term><option>--split</option> <parameter>specification</parameter></term>

     <listitem>
      <para>
       Splits the output file after a given size or a given time.  Please note that tracks can only be split right before a key frame.  Due
       to buffering &mkvmerge; will split right before the next key frame after the split point has been reached.  Therefore the split point
       may be a bit off from what the user has specified.
      </para>

      <para>
       At the moment &mkvmerge; supports four different modes.
      </para>

      <orderedlist>
       <listitem>
        <para>
         Splitting by size.
        </para>

        <para>
         Syntax: <option>--split</option> <optional><literal>size:</literal></optional><parameter>d</parameter><optional>k|m|g</optional>
        </para>

        <para>
         Examples: <code>--split size:700m</code> or <code>--split 150000000</code>
        </para>

        <para>
         The parameter <parameter>d</parameter> may end with '<literal>k</literal>', '<literal>m</literal>' or '<literal>g</literal>' to
         indicate that the size is in KB, MB or GB respectively.  Otherwise a size in bytes is assumed.  After the current output file has
         reached this size limit a new one will be started.
        </para>

        <para>
         The '<literal>size:</literal>' prefix may be omitted for compatibility reasons.
        </para>
       </listitem>

       <listitem>
        <para>
         Splitting after a duration.
        </para>

        <para>
         Syntax: <option>--split</option> <optional><literal>duration:</literal></optional><parameter>HH:MM:SS.nnnnnnnnn</parameter>|<parameter>d</parameter>s
        </para>

        <para>
         Examples: <code>--split duration:00:60:00.000</code> or <code>--split 3600s</code>
        </para>

        <para>
         The parameter must either have the form <parameter>HH:MM:SS.nnnnnnnnn</parameter> for specifying the duration in up to nano-second
         precision or be a number <parameter>d</parameter> followed by the letter '<literal>s</literal>' for the duration in
         seconds. <parameter>HH</parameter> is the number of hours, <parameter>MM</parameter> the number of minutes,
         <parameter>SS</parameter> the number of seconds and <parameter>nnnnnnnnn</parameter> the number of nanoseconds.  Both the number of
         hours and the number of nanoseconds can be omitted.  There can be up to nine digits after the decimal point.  After the duration of
         the contents in the current output has reached this limit a new output file will be started.
        </para>

        <para>
         The '<literal>duration:</literal>' prefix may be omitted for compatibility reasons.
        </para>
       </listitem>

       <listitem>
        <para>
         Splitting after specific timecodes.
        </para>

        <para>
         Syntax: <option>--split</option> <literal>timecodes:</literal><parameter>A</parameter><optional>,<parameter>B</parameter><optional>,<parameter>C</parameter>...</optional></optional>
        </para>

        <para>
         Example: <code>--split timecodes:00:45:00.000,01:20:00.250,6300s</code>
        </para>

        <para>
         The parameters <parameter>A</parameter>, <parameter>B</parameter>, <parameter>C</parameter> etc must all have the same format as the
         ones used for the duration (see above). The list of timecodes is separated by commas.  After the input stream has reached the
         current split point's timecode a new file is created. Then the next split point given in this list is used.
        </para>

        <para>
         The '<literal>timecodes:</literal>' prefix must not be omitted.
        </para>
       </listitem>

       <listitem>
        <para>
         Keeping specific parts by specifying timecode ranges while discarding others.
        </para>

        <para>
         Syntax: <option>--split</option> <literal>parts:</literal><parameter>start1</parameter>-<parameter>end1</parameter><optional>,<optional>+</optional><parameter>start2</parameter>-<parameter>end2</parameter><optional>,<optional>+</optional><parameter>start3</parameter>-<parameter>end3</parameter>...</optional></optional>
        </para>

        <para>
         Examples:
         <orderedlist>
          <listitem><para><code>--split parts:00:01:20-00:02:45,00:05:50-00:10:30</code></para></listitem>
          <listitem><para><code>--split parts:00:01:20-00:02:45,+00:05:50-00:10:30</code></para></listitem>
          <listitem><para><code>--split parts:-00:02:45,00:05:50-</code></para></listitem>
         </orderedlist>
        </para>

        <para>
         The <literal>parts</literal> mode tells &mkvmerge; to keep certain ranges of timecodes while discarding others. The ranges to keep
         have to be listed after the <literal>parts:</literal> keyword and be separated by commas. A range itself consists of a start and an
         end timecode in the same format the other variations of <parameter>--split</parameter> accept (e.g. both
         <literal>00:01:20</literal> and <literal>80s</literal> refer to the same timecode).
        </para>

        <para>
         If a start timecode is left out then it defaults to the previous range's end timecode. If there was no previous range then it
         defaults to the start of the file (see example 3).
        </para>

        <para>
         If an end timecode is left out then it defaults to the end of the source files which basically tells &mkvmerge; to keep the rest (see
         example 3).
        </para>

        <para>
         Normally each range will be written to a new file. This can be changed so that consecutive ranges are written to the same file. For
         that the user has to prefix the start timecode with a <literal>+</literal>. This tells &mkvmerge; not to create a new file and
         instead append the range to the same file the previous range was written to. Timecodes will be adjusted so that there will be no
         gap in the output file even if there was a gap in the two ranges in the input file.
        </para>

        <para>
         In example 1 &mkvmerge; will create two files. The first will contain the content starting from <literal>00:01:20</literal> until
         <literal>00:02:45</literal>. The second file will contain the content starting from <literal>00:05:50</literal> until
         <literal>00:10:30</literal>.
        </para>

        <para>
         In example 2 &mkvmerge; will create only one file. This file will contain both the content starting from <literal>00:01:20</literal>
         until <literal>00:02:45</literal> and the content starting from <literal>00:05:50</literal> until <literal>00:10:30</literal>.
        </para>

        <para>
         In example 3 &mkvmerge; will create two files. The first will contain the content from the start of the source files until
         <literal>00:02:45</literal>. The second file will contain the content starting from <literal>00:05:50</literal> until the end of
         the source files.
        </para>

        <note>
          <para>
            Note that &mkvmerge; only makes decisions about splitting at key frame positions. This applies to both the start and the end of
            each range. So even if an end timecode is between two key frames &mkvmerge; will continue outputting the frames up to but
            excluding the following key frame.
          </para>
        </note>
       </listitem>

       <listitem>
        <para>
         Keeping specific parts by specifying frame/field number ranges while discarding others.
        </para>

        <para>
         Syntax: <option>--split</option> <literal>parts-frames:</literal><parameter>start1</parameter>-<parameter>end1</parameter><optional>,<optional>+</optional><parameter>start2</parameter>-<parameter>end2</parameter><optional>,<optional>+</optional><parameter>start3</parameter>-<parameter>end3</parameter>...</optional></optional>
        </para>

        <para>
         Examples:
         <orderedlist>
          <listitem><para><code>--split parts-frames:137-258,548-1211</code></para></listitem>
          <listitem><para><code>--split parts-frames:733-912,+1592-2730</code></para></listitem>
          <listitem><para><code>--split parts-frames:-430,2512-</code></para></listitem>
         </orderedlist>
        </para>

        <para>
         The <literal>parts-frames</literal> mode tells &mkvmerge; to keep certain ranges of frame/field numbers while discarding
         others. The ranges to keep have to be listed after the <literal>parts-frames:</literal> keyword and be separated by commas. A range
         itself consists of a start and an end frame/field number. Numbering starts at 1.
        </para>

        <para>
         If a start number is left out then it defaults to the previous range's end number. If there was no previous range then it defaults
         to the start of the file (see example 3).
        </para>

        <para>
         If an end number is left out then it defaults to the end of the source files which basically tells &mkvmerge; to keep the rest (see
         example 3).
        </para>

        <para>
         Normally each range will be written to a new file. This can be changed so that consecutive ranges are written to the same file. For
         that the user has to prefix the start number with a <literal>+</literal>. This tells &mkvmerge; not to create a new file and
         instead append the range to the same file the previous range was written to. Timecodes will be adjusted so that there will be no
         gap in the output file even if there was a gap in the two ranges in the input file.
        </para>

        <note>
          <para>
            Note that &mkvmerge; only makes decisions about splitting at key frame positions. This applies to both the start and the end of
            each range. So even if an end frame/field number is between two key frames &mkvmerge; will continue outputting the frames up to
            but excluding the following key frame.
          </para>
        </note>

        <para>
         In example 1 &mkvmerge; will create two files. The first will contain the content starting from the first key frame at or after
         <literal>137</literal> up to but excluding the first key frame at or after <literal>258</literal>. The second file will contain the
         content starting from <literal>548</literal> until <literal>1211</literal>.
        </para>

        <para>
         In example 2 &mkvmerge; will create only one file. This file will contain both the content starting from <literal>733</literal>
         until <literal>912</literal> and the content starting from <literal>1592</literal> until <literal>2730</literal>.
        </para>

        <para>
         In example 3 &mkvmerge; will create two files. The first will contain the content from the start of the source files until
         <literal>430</literal>. The second file will contain the content starting from <literal>2512</literal> until the end of the source
         files.
        </para>

        <para>
          This mode considers only the first video track that is output.  If no video track is output no splitting will occur.
        </para>

        <note>
          <para>
            The numbers given with this argument are interpreted based on the number of &matroska; blocks that are output.  A single &matroska;
            block contains either a full frame (for progressive content) or a single field (for interlaced content).  mkvmerge does not
            distinguish between those two and simply counts the number of blocks.  For example: If one wanted to split after the 25th full
            frame with interlaced content one would have to use <literal>50</literal> (two fields per full frame) as the split point.
          </para>
        </note>
       </listitem>

       <listitem>
        <para>
         Splitting after specific frames/fields.
        </para>

        <para>
         Syntax: <option>--split</option> <literal>frames:</literal><parameter>A</parameter><optional>,<parameter>B</parameter><optional>,<parameter>C</parameter>...</optional></optional>
        </para>

        <para>
         Example: <code>--split frames:120,237,891</code>
        </para>

        <para>
         The parameters <parameter>A</parameter>, <parameter>B</parameter>, <parameter>C</parameter> etc must all be positive integers.
         Numbering starts at 1.  The list of frame/field numbers is separated by commas.  After the input stream has reached the current
         split point's frame/field number a new file is created.  Then the next split point given in this list is used.
        </para>

        <para>
         The '<literal>frames:</literal>' prefix must not be omitted.
        </para>

        <para>
          This mode considers only the first video track that is output.  If no video track is output no splitting will occur.
        </para>

        <note>
          <para>
            The numbers given with this argument are interpreted based on the number of &matroska; blocks that are output.  A single &matroska;
            block contains either a full frame (for progressive content) or a single field (for interlaced content).  mkvmerge does not
            distinguish between those two and simply counts the number of blocks.  For example: If one wanted to split after the 25th full
            frame with interlaced content one would have to use <literal>50</literal> (two fields per full frame) as the split point.
          </para>
        </note>
       </listitem>

       <listitem>
        <para>
         Splitting before specific chapters.
        </para>

        <para>
         Syntax: <option>--split</option> <literal>chapters:all</literal> or <option>--split</option>
         <literal>chapters:</literal><parameter>A</parameter><optional>,<parameter>B</parameter><optional>,<parameter>C</parameter>...</optional></optional>
        </para>

        <para>
         Example: <code>--split chapters:5,8</code>
        </para>

        <para>
         The parameters <parameter>A</parameter>, <parameter>B</parameter>, <parameter>C</parameter> etc must all be positive integers.
         Numbering starts at 1.  The list of chapter numbers is separated by commas.  Splitting will occur right before the first key frame
         whose timecode is equal to or bigger than the start timecode for the chapters whose numbers are listed.  A chapter starting at 0s
         is never considered for splitting and discarded silently.
        </para>

        <para>
          The keyword <literal>all</literal> can be used instead of listing all chapter numbers manually.
        </para>

        <para>
         The '<literal>chapters:</literal>' prefix must not be omitted.
        </para>

        <note>
          <para>
            The &matroska; file format supports arbitrary deeply nested chapter structures called 'edition entries' and 'chapter atoms'.
            However, this mode only considers the top-most level of chapters across all edition entries.
          </para>
        </note>
       </listitem>
      </orderedlist>

      <para>
       For this splitting mode the output filename is treated differently than for the normal operation. It may contain a
       <function>printf</function> like expression '<code>%d</code>' including an optional field width,
       e.g. '<code>%02d</code>'. 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 '<code>-%03d</code>' is assumed right before the file's
       extension: '<code>-o output.mkv</code>' would result in '<code>output-001.mkv</code>' and so on. If there's no extension
       then '<code>-%03d</code>' will be appended to the name.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.link">
     <term><option>--link</option></term>
     <listitem>
      <para>
       Link files to one another when splitting the output file. See the section on <link linkend="mkvmerge.file_linking">file linking</link>
       below for details.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--link-to-previous</option> <parameter>segment-UID</parameter></term>
     <listitem>
      <para>
       Links the first output file to the segment with the segment UID given by the <parameter>segment-UID</parameter> parameter. See the
       section on <link linkend="mkvmerge.file_linking">file linking</link> below for details.
      </para>

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

    <varlistentry>
     <term><option>--link-to-next</option> <parameter>segment-UID</parameter></term>
     <listitem>
      <para>
       Links the last output file to the segment with the segment UID given by the <parameter>segment-UID</parameter> parameter. See the
       section on <link linkend="mkvmerge.file_linking">file linking</link> below for details.
      </para>

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

    <varlistentry>
     <term><option>--append-mode</option> <parameter>mode</parameter></term>
     <listitem>
      <para>
       Determines how timecodes are calculated when appending files.  The parameter <parameter>mode</parameter> can have two values:
       '<literal>file</literal>' which is also the default and '<literal>track</literal>'.
      </para>

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

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

      <para>
       Subtitle tracks are always treated as if '<literal>file</literal>' mode were active even if '<literal>track</literal>' mode actually
       is.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--append-to</option> <parameter>SFID1:STID1:DFID1:DTID1<optional>,...</optional></parameter></term>
     <listitem>
      <para>
       This option controls to which track another track is appended.  Each spec contains four IDs: a file ID, a track ID, a second file ID
       and a second track ID.  The first pair, "source file ID" and "source track ID", identifies the track that is to be appended.  The
       second pair, "destination file ID" and "destination track ID", identifies the track the first one is appended to.
      </para>

      <para>
       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 <command>mkvmerge -o output.mkv part1.mkv +part2.mkv</command>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>+</option></term>
     <listitem>
      <para>
       A single '+' causes the next file to be appended instead of added. The '+' can also be put in front of the next file name. Therefore
       the following two commands are equivalent:
      </para>

      <screen>$ mkvmerge -o full.mkv file1.mkv + file2.mkv
$ mkvmerge -o full.mkv file1.mkv +file2.mkv</screen>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>[</option> <parameter>file1</parameter> <parameter>file2</parameter> <option>]</option></term>
     <listitem>
      <para>
       If multiple file names are contained in a pair of square brackets then the second and all following files will be appended to the first file named within the brackets.
      </para>

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

      <screen>$ mkvmerge -o full.mkv file1.mkv + file2.mkv
$ mkvmerge -o full.mkv '[' file1.mkv file2.mkv ']'</screen>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.prevent_concatenation">
     <term><option>=</option></term>
     <listitem>
      <para>
       Normally &mkvmerge; looks for files in the same directory as an input file that have the same base name and only differ in their
       running number (e.g. 'VTS_01_1.VOB', 'VTS_01_2.VOB', 'VTS_01_3.VOB' etc) and treats all of those files as if they were concatenated
       into a single big file. This option, a single '=', causes mkvmerge not to look for those additional files.
      </para>

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

      <screen>$ mkvmerge -o full.mkv = file1.mkv
$ mkvmerge -o full.mkv =file1.mkv</screen>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.concatenation">
     <term><option>(</option> <parameter>file1</parameter> <parameter>file2</parameter> <option>)</option></term>
     <listitem>
      <para>
       If multiple file names are contained in a pair of parenthesis then those files will be treated as if they were concatenated into a
       single big file consisting of the content of each of the files one after the other.
      </para>

      <para>
       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.
      </para>

      <para>
       Putting a file name into parenthesis also prevents &mkvmerge; from looking for additional files with the same base name as described
       in <link linkend="mkvmerge.description.prevent_concatenation">option <option>=</option></link>. Therefore these two command lines are
       equivalent:
      </para>

      <screen>$ mkvmerge -o out.mkv = file.mkv
$ mkvmerge -o out.mkv '(' file.mkv ')'</screen>

      <para>
       Several things should be noted:
      </para>

      <orderedlist>
       <listitem>
        <para>
         There must be spaces both after the opening and before the closing parenthesis.
        </para>
       </listitem>

       <listitem>
        <para>
         Every parameter between parenthesis is interpreted as a file name. Therefore all options applying to this logical file must be listed before the opening parenthesis.
        </para>
       </listitem>

       <listitem>
        <para>
         Some shells treat parenthesis as special characters. Hence you must escape or quote them as shown in the example above.
        </para>
       </listitem>
      </orderedlist>
     </listitem>
    </varlistentry>
   </variablelist>

  </refsect2>

  <refsect2>
   <title>Attachment support (more global options)</title>

   <variablelist>
    <varlistentry  id="mkvmerge.description.attachment_description">
     <term><option>--attachment-description</option> <parameter>description</parameter></term>
     <listitem>
      <para>
       Plain text description of the following attachment. Applies to the next <link
       linkend="mkvmerge.description.attach_file"><option>--attach-file</option></link> or <option>--attach-file-once</option> option.

      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--attachment-mime-type</option> <parameter>MIME type</parameter></term>
     <listitem>
      <para>
       <abbrev >MIME</abbrev> type of the following attachment. Applies to the next <link
       linkend="mkvmerge.description.attach_file"><option>--attach-file</option></link> or <link
       linkend="mkvmerge.description.attach_file"><option>--attach-file-once</option></link> option.  A list of officially recognized
       <abbrev>MIME</abbrev> types can be found e.g. at <ulink url="http://www.iana.org/assignments/media-types/">the IANA
       homepage</ulink>. The <abbrev>MIME</abbrev> type is mandatory for an attachment.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--attachment-name</option> <parameter>name</parameter></term>
     <listitem>
      <para>
       Sets the name that will be stored in the output file for this attachment.  If this option is not given then the name will be derived
       from the file name of the attachment as given with the <link
       linkend="mkvmerge.description.attach_file"><option>--attach-file</option></link> or the <link
       linkend="mkvmerge.description.attach_file"><option>--attach-file-once</option></link> option.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.attach_file">
     <term>
      <option>--attach-file</option> <parameter>file-name</parameter>,
      <option>--attach-file-once</option> <parameter>file-name</parameter>
     </term>
     <listitem>
      <para>
       Creates a file attachment inside the &matroska; file. The <abbrev>MIME</abbrev> type must have been set before this option can used. The
       difference between the two forms is that during splitting the files attached with <option>--attach-file</option> are attached to all
       output files while the ones attached with <option>--attach-file-once</option> are only attached to the first file created.  If
       splitting is not used then both do the same.
      </para>

      <para>
       &mkvextract; can be used to extract attached files from a &matroska; file.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Options that can be used for each input file</title>

   <variablelist>
    <varlistentry>
     <term><option>-a</option>, <option>--audio-tracks</option> <parameter><optional>!</optional>n,m,...</parameter></term>
     <listitem>
      <para>
       Copy the audio tracks <parameter>n</parameter>, <parameter>m</parameter> etc. The numbers are track IDs which can be obtained with the
       <link linkend="mkvmerge.description.identify"><option>--identify</option></link> switch. They're not simply the track numbers (see
       section <link linkend="mkvmerge.track_ids">track IDs</link>). Default: copy all audio tracks.
      </para>

      <para>
       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.
      </para>

      <para>
       Default: copy all tracks of this kind.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy all tracks of this kind but the ones listed
       after the <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-d</option>, <option>--video-tracks</option> <parameter><optional>!</optional>n,m,...</parameter></term>
     <listitem>
      <para>
       Copy the video tracks <parameter>n</parameter>, <parameter>m</parameter> etc. The numbers are track IDs which can be obtained with the
       <link linkend="mkvmerge.description.identify"><option>--identify</option></link> switch. They're not simply the track numbers (see
       section <link linkend="mkvmerge.track_ids">track IDs</link>). Default: copy all video tracks.
      </para>

      <para>
       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.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy all tracks of this kind but the ones listed
       after the <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-s</option>, <option>--subtitle-tracks</option> <parameter><optional>!</optional>n,m,...</parameter></term>
     <listitem>
      <para>
       Copy the subtitle tracks <parameter>n</parameter>, <parameter>m</parameter> etc. The numbers are track IDs which can be obtained with
       the <link linkend="mkvmerge.description.identify"><option>--identify</option></link> switch. They're not simply the track numbers (see
       section <link linkend="mkvmerge.track_ids">track IDs</link>). Default: copy all subtitle tracks.
      </para>

      <para>
       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.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy all tracks of this kind but the ones listed
       after the <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-b</option>, <option>--button-tracks</option> <parameter><optional>!</optional>n,m,...</parameter></term>
     <listitem>
      <para>
       Copy the button tracks <parameter>n</parameter>, <parameter>m</parameter> etc. The numbers are track IDs which can be obtained with
       the <link linkend="mkvmerge.description.identify"><option>--identify</option></link> switch. They're not simply the track numbers (see
       section <link linkend="mkvmerge.track_ids">track IDs</link>). Default: copy all button tracks.
      </para>

      <para>
       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.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy all tracks of this kind but the ones listed
       after the <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--track-tags</option> <parameter><optional>!</optional>n,m,...</parameter></term>
     <listitem>
      <para>
       Copy the tags for tracks <parameter>n</parameter>, <parameter>m</parameter> etc.  The numbers are track IDs which can be obtained with
       the <link linkend="mkvmerge.description.identify"><option>--identify</option></link> switch (see section <link
       linkend="mkvmerge.track_ids">track IDs</link>).  They're not simply the track numbers.  Default: copy tags for all tracks.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy everything but the IDs listed after the
       <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.attachments">
     <term><option>-m</option>, <option>--attachments</option> <parameter><optional>!</optional>n<optional>:all|first</optional>,m<optional>:all|first</optional>,...</parameter></term>
     <listitem>
      <para>
       Copy the attachments with the IDs <parameter>n</parameter>, <parameter>m</parameter> etc to all or only the first output file. Each ID
       can be followed by either '<literal>:all</literal>' (which is the default if neither is entered) or '<literal>:first</literal>'. If
       splitting is active then those attachments whose IDs are specified with '<literal>:all</literal>' are copied to all of the resulting
       output files while the others are only copied into the first output file. If splitting is not active then both variants have the same
       effect.
      </para>

      <para>
       The default is to copy all attachments to all output files.
      </para>

      <para>
       If the IDs are prefixed with <literal>!</literal> then the meaning is reversed: copy everything but the IDs listed after the
       <literal>!</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-A</option>, <option>--no-audio</option></term>
     <listitem>
      <para>
       Don't copy any audio track from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-D</option>, <option>--no-video</option></term>
     <listitem>
      <para>
       Don't copy any video track from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-S</option>, <option>--no-subtitles</option></term>
     <listitem>
      <para>
       Don't copy any subtitle track from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-B</option>, <option>--no-buttons</option></term>
     <listitem>
      <para>
       Don't copy any button track from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-T</option>, <option>--no-track-tags</option></term>
     <listitem>
      <para>
       Don't copy any track specific tags from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.no_chapters">
     <term><option>--no-chapters</option></term>
     <listitem>
      <para>
       Don't copy chapters from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.no_attachments">
     <term><option>-M</option>, <option>--no-attachments</option></term>
     <listitem>
      <para>
       Don't copy attachments from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--no-global-tags</option></term>
     <listitem>
      <para>
       Don't copy global tags from this file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chapter-charset</option> <parameter>character-set</parameter></term>
     <listitem>
      <para>
       Sets the charset that is used for the conversion to UTF-8 for chapter information contained in the source file. See the section about
       <link linkend="mkvmerge.text_files_and_charsets"> text files and character sets</link> for an explanation how &mkvmerge; converts
       between character sets.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chapter-language</option> <parameter>language-code</parameter></term>
     <listitem>
      <para>
       Sets the ISO639-2 language code that is written for each chapter entry.  This option can be used for source files that contain
       chapters but no information about the chapters' languages, e.g. for MP4 and OGM files.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-y</option>, <option>--sync</option> <parameter>TID:d<optional>,o<optional>/p</optional></optional></parameter></term>
     <listitem>
      <para>
       Adjust the timecodes of the track with the id <parameter>TID</parameter> by <parameter>d</parameter> ms. The track IDs are the same as
       the ones given with <link linkend="mkvmerge.description.identify"><option>--identify</option></link> (see section <link
       linkend="mkvmerge.track_ids">track IDs</link>).
      </para>

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

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

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.cues">
     <term><option>--cues</option> <parameter>TID:none|iframes|all</parameter></term>
     <listitem>
      <para>
       Controls for which tracks cue (index) entries are created for the given track (see section <link linkend="mkvmerge.track_ids">track
       IDs</link>). '<literal>none</literal>' inhibits the creation of cue entries.  For '<literal>iframes</literal>' only blocks with
       no backward or forward references ( = I frames in video tracks) are put into the cue sheet. '<literal>all</literal>' causes
       &mkvmerge; to create cue entries for all blocks which will make the file very big.
      </para>

      <para>
       The default is '<literal>iframes</literal>' for video and subtitle tracks and '<literal>none</literal>' for audio tracks.  See also
       option <link linkend="mkvmerge.description.no_cues"><option>--no-cues</option></link> which inhibits the creation of cue entries
       regardless of the <option>--cues</option> options used.
      </para>

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--default-track</option> <parameter>TID<optional>:bool</optional></parameter></term>
     <listitem>
      <para>
       Sets the 'default' flag for the given track (see section <link linkend="mkvmerge.track_ids">track IDs</link>) if the optional argument
       <parameter>bool</parameter> is not present.  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, buttons) can have his 'default' flag set.
       If the user wants no track to have the default track flag set then he has to set <parameter>bool</parameter> to <constant>0</constant>
       for all tracks.
      </para>

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--forced-track</option> <parameter>TID<optional>:bool</optional></parameter></term>
     <listitem>
      <para>
       Sets the 'forced' flag for the given track (see section <link linkend="mkvmerge.track_ids">track IDs</link>) if the optional argument
       <parameter>bool</parameter> is not present. A player must play all tracks for which this flag is set to <constant>1</constant>.
      </para>

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--blockadd</option> <parameter>TID:level</parameter></term>
     <listitem>
      <para>
       Keep only the <classname>BlockAdditions</classname> up to the level <parameter>level</parameter> for the given track.  The default is
       to keep all levels.  This option only affects certain kinds of codecs like WAVPACK4.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.track_name">
     <term><option>--track-name</option> <parameter>TID:name</parameter></term>
     <listitem>
      <para>
       Sets the track name for the given track (see section <link linkend="mkvmerge.track_ids">track IDs</link>) to
       <parameter>name</parameter>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.language">
     <term><option>--language</option> <parameter>TID:language</parameter></term>
     <listitem>
      <para>
       Sets the language for the given track (see section <link linkend="mkvmerge.track_ids">track IDs</link>). Both ISO639-2 language codes
       and ISO639-1 country codes are allowed. The country codes will be converted to language codes automatically.  All languages including
       their ISO639-2 codes can be listed with the <link
       linkend="mkvmerge.description.list_languages"><option>--list-languages</option></link> option.
      </para>

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.tags">
     <term><option>-t</option>, <option>--tags</option> <parameter>TID:file-name</parameter></term>
     <listitem>
      <para>
       Read tags for the track with the number <parameter>TID</parameter> from the file <parameter>file-name</parameter>. See the section
       about <link linkend="mkvmerge.tags">tags</link> below for details.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--aac-is-sbr</option> <parameter>TID<optional>:0|1</optional></parameter></term>
     <listitem>
      <para>
       Tells &mkvmerge; that the track with the ID <parameter>TID</parameter> is <abbrev>SBR AAC</abbrev> (also known as
       <abbrev>HE-AAC</abbrev> or <abbrev>AAC+</abbrev>). This options is needed if a) the source file is an <abbrev>AAC</abbrev> file
       (<emphasis>not</emphasis> for a &matroska; file) and b) the <abbrev>AAC</abbrev> file contains <abbrev>SBR AAC</abbrev> data.  The
       reason for this switch is that it is technically impossible to automatically tell normal <abbrev>AAC</abbrev> data from <abbrev>SBR
       AAC</abbrev> data without decoding a complete <abbrev>AAC</abbrev> frame. As there are several patent issues with <abbrev>AAC</abbrev>
       decoders &mkvmerge; will never contain this decoding stage. So for <abbrev>SBR AAC</abbrev> files this switch is mandatory. The
       resulting file might not play back correctly or even not at all if the switch was omitted.
      </para>

      <para>
       If the source file is a &matroska; file then the <classname>CodecID</classname> should be enough to detect <abbrev>SBR
       AAC</abbrev>. However, if the <classname>CodecID</classname> is wrong then this switch can be used to correct that.
      </para>

      <para>
       If mkvmerge wrongfully detects that an <abbrev>AAC</abbrev> file is <abbrev>SBR</abbrev> then you can add
       '<literal>:0</literal>' to the track ID.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--reduce-to-core</option> <parameter>TID</parameter></term>
     <listitem>
      <para>
       Some audio codecs have a lossy core and optional extensions that implement lossless decoding. This option tells &mkvmerge; to only
       copy the core but not the extensions. By default &mkvmerge; copies both the core and the extensions.
      </para>

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

    <varlistentry>
     <term><option>--timecodes</option> <parameter>TID:file-name</parameter></term>
     <listitem>
      <para>
       Read the timecodes to be used for the specific track ID from <parameter>file-name</parameter>.  These timecodes forcefully override
       the timecodes that &mkvmerge; normally calculates. Read the section about <link linkend="mkvmerge.external_timecode_files">external
       timecode files</link>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.default_duration">
     <term><option>--default-duration</option> <parameter>TID:x</parameter></term>
     <listitem>
      <para>
       Forces the default duration of a given track to the specified value.  Also modifies the track's timecodes to match the default
       duration.  The argument <parameter>x</parameter> must be postfixed with '<literal>s</literal>', '<literal>ms</literal>',
       '<literal>us</literal>', '<literal>ns</literal>', '<literal>fps</literal>', '<literal>p</literal>' or '<literal>i</literal>' to
       specify the default duration in seconds, milliseconds, microseconds, nanoseconds, 'frames per second', 'progressive frames per
       second' or 'interlaced frames per second' respectively. The number <parameter>x</parameter> itself can be a floating point number or
       a fraction.
      </para>

      <para>
       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.
      </para>

      <para>
       This option can also be used to change the <abbrev>FPS</abbrev> of video tracks without having to use an external timecode file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.fix_bitstream_timing_information">
     <term><option>--fix-bitstream-timing-information</option> <parameter>TID<optional>:0|1</optional></parameter></term>
     <listitem>
      <para>
       Normally &mkvmerge; does not change the timing information (frame/field rate) stored in the video bitstream. With this option that
       information is adjusted to match the container timing information. The container timing information can come from various sources:
       from the command line (see option <link linkend="mkvmerge.description.default_duration"><option>--default-duration</option></link>),
       the source container or derived from the bitstream.
      </para>

      <note>
       <para>This has only been implemented for AVC/h.264 video tracks so far.</para>
      </note>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--nalu-size-length</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Forces the <abbrev>NALU</abbrev> size length to <parameter>n</parameter> bytes.  This parameter is only used if the
       <foreignphrase>AVC/h.264</foreignphrase> elementary stream packetizer is used.  If left out it defaults to 4 bytes, but there are
       files that contain frames or slices that are all smaller than 65536 bytes.  For such files you can use this parameter and decrease
       the size to 2.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.compression">
     <term><option>--compression</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Selects the compression method to be used for the track. Note that the player also has to support this method. Valid values are
       '<literal>none</literal>', '<literal>zlib</literal>' and '<literal>mpeg4_p2</literal>'/'<literal>mpeg4p2</literal>'.
      </para>
      <para>
       The compression method '<literal>mpeg4_p2</literal>'/'<literal>mpeg4p2</literal>' is a special compression method called
       '<foreignphrase>header removal</foreignphrase>' that is only available for <abbrev>MPEG4</abbrev> part 2 video tracks.
      </para>
      <para>
       The default for some subtitle types is '<literal>zlib</literal>' compression. This compression method is also the one that most if
       not all playback applications support. Support for other compression methods other than '<literal>none</literal>' is not assured.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Options that only apply to video tracks</title>

   <variablelist>
    <varlistentry>
     <term><option>-f</option>, <option>--fourcc</option> <parameter>TID:FourCC</parameter></term>
     <listitem>
      <para>
       Forces the <classname>FourCC</classname> to the specified value. Works only for video tracks in the '<foreignphrase>MS compatibility
       mode</foreignphrase>'.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.display_dimensions">
     <term><option>--display-dimensions</option> <parameter>TID:widthxheight</parameter></term>
     <listitem>
      <para>
       &matroska; files contain two values that set the display properties that a player should scale the image on playback to: display width
       and display height.  These values can be set with this option, e.g. '<literal>1:640x480</literal>'.
      </para>

      <para>
       Another way to specify the values is to use the <link
       linkend="mkvmerge.description.aspect_ratio"><option>--aspect-ratio</option></link> or the <link
       linkend="mkvmerge.description.aspect_ratio_factor"><option>--aspect-ratio-factor</option></link> option (see below).  These options
       are mutually exclusive.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.aspect_ratio">
     <term><option>--aspect-ratio</option> <parameter>TID:ratio|width/height</parameter></term>
     <listitem>
      <para>
       &matroska; files contain two values that set the display properties that a player should scale the image on playback to: display width
       and display height.  With this option &mkvmerge; will automatically calculate the display width and display height based on the
       image's original width and height and the aspect ratio given with this option.  The ratio can be given either as a floating point
       number <parameter>ratio</parameter> or as a fraction '<parameter>width</parameter>/<parameter>height</parameter>',
       e.g. '<literal>16/9</literal>'.
      </para>

      <para>
       Another way to specify the values is to use the <link
       linkend="mkvmerge.description.aspect_ratio_factor"><option>--aspect-ratio-factor</option></link> or <link
       linkend="mkvmerge.description.display_dimensions"><option>--display-dimensions</option></link> options (see above and below). These
       options are mutually exclusive.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.aspect_ratio_factor">
     <term><option>--aspect-ratio-factor</option> <parameter>TID:factor|n/d</parameter></term>
     <listitem>
      <para>
       Another way to set the aspect ratio is to specify a <parameter>factor</parameter>. The original aspect ratio is first multiplied with
       this <parameter>factor</parameter> and used as the target aspect ratio afterwards.
      </para>

      <para>
       Another way to specify the values is to use the <link
       linkend="mkvmerge.description.aspect_ratio"><option>--aspect-ratio</option></link> or <link
       linkend="mkvmerge.description.display_dimensions"><option>--display-dimensions</option></link> options (see above). These options are
       mutually exclusive.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--cropping</option> <parameter>TID:left,top,right,bottom</parameter></term>
     <listitem>
      <para>
       Sets the pixel cropping parameters of a video track to the given values.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--colour-matrix</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the matrix coefficients of the video used to derive luma and chroma values from red, green and blue color primaries. The
       parameter <parameter>n</parameter> is an integer rangeing from <constant>0</constant> and <constant>10</constant>.
      </para>

      <para>
       Valid values and their meaning are:
      </para>

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

    <varlistentry>
     <term><option>--colour-bits-per-channel</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the number of coded bits for a colour channel. A value of <constant>0</constant> indicates that the number of bits is
       unspecified.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chroma-subsample</option> <parameter>TID:hori,vert</parameter></term>
     <listitem>
      <para>
       The amount of pixels to remove in the Cr and Cb channels for every pixel not removed horizontally/vertically.
      </para>

      <para>
       Example: For video with 4:2:0 chroma subsampling, the parameter should be set to
       <code><parameter>TID</parameter>:<constant>1</constant>,<constant>1</constant></code>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--cb-subsample</option> <parameter>TID:hori,vert</parameter></term>
     <listitem>
      <para>
       The amount of pixels to remove in the Cb channel for every pixel not removed horizontally/vertically. This is additive with
       <option>--chroma-subsample</option>.
      </para>

      <para>
       Example: For video with 4:2:1 chroma subsampling, the parameter <option>--chroma-subsample</option> should be set to
       <code><parameter>TID</parameter>:<constant>1</constant>,<constant>0</constant></code> and Cb-subsample should be set to
       <code><parameter>TID</parameter>:<constant>1</constant>,<constant>0</constant></code>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chroma-siting</option> <parameter>TID:hori,vert</parameter></term>
     <listitem>
      <para>
       Sets how chroma is sited horizontally/vertically (<constant>0</constant>: unspecified, <constant>1</constant>: top collocated,
       <constant>2</constant>: half).
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--colour-range</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the clipping of the color ranges (<constant>0</constant>: unspecified, <constant>1</constant>: broadcast range,
       <constant>2</constant>: full range (no clipping), <constant>3</constant>: defined by MatrixCoefficients/TransferCharacteristics).
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--colour-transfer-characteristics</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       The transfer characteristics of the video.
      </para>

      <para>
       Valid values and their meaning are:
      </para>

      <para>
       <constant>0</constant>: reserved, <constant>1</constant>: ITU-R BT.709, <constant>2</constant>: unspecified, <constant>3</constant>:
       reserved, <constant>4</constant>: gamma 2.2 curve, <constant>5</constant>: gamma 2.8 curve, <constant>6</constant>: SMPTE 170M,
       <constant>7</constant>: SMPTE 240M, <constant>8</constant>: linear, <constant>9</constant>: log, <constant>10</constant>: log sqrt,
       <constant>11</constant>: IEC 61966-2-4, <constant>12</constant>: ITU-R BT.1361 extended colour gamut, <constant>13</constant>: IEC
       61966-2-1, <constant>14</constant>: ITU-R BT.2020 10 bit, <constant>15</constant>: ITU-R BT.2020 12 bit, <constant>16</constant>:
       SMPTE ST 2084, <constant>17</constant>: SMPTE ST 428-1; <constant>18</constant>: ARIB STD-B67 (HLG)
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--colour-primaries</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the colour primaries of the video.
      </para>

      <para>
       Valid values and their meaning are:
      </para>

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

    <varlistentry>
     <term><option>--max-content-light</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
      Sets the maximum brightness of a single pixel (Maximum Content Light Level) in candelas per square meter (cd/m²). The value of
      <parameter>n</parameter> should be a non-negtive integer.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--max-frame-light</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the maximum brightness of a single full frame (Maximum Frame-Average Light Level) in candelas per square meter (cd/m²). The
       value of <parameter>n</parameter> should be a non-negtive
      integer.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--chromaticity-coordinates</option>
     <parameter>TID:red-x,red-y,green-x,green-y,blue-x,blue-y</parameter></term>
     <listitem>
      <para>
       Sets the red/green/blue chromaticity coordinates as defined by CIE 1931.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--white-colour-coordinates</option> <parameter>TID:x,y</parameter></term>
     <listitem>
      <para>
       Sets the white colour chromaticity coordinates as defined by CIE 1931.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--max-luminance</option> <parameter>TID:float</parameter></term>
     <listitem>
      <para>
       Sets the maximum luminance in candelas per square meter (cd/m²). The value should be less than 9999.99.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--min-luminance</option> <parameter>TID:float</parameter></term>
     <listitem>
      <para>
       Sets the mininum luminance in candelas per square meter (cd/m²). The value should be less than 999.9999.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.field_order">
     <term><option>--field-order</option> <parameter>TID:n</parameter></term>
     <listitem>
      <para>
       Sets the field order for the video track with the track ID <parameter>TID</parameter>.  The order must be one of the following numbers:
      </para>

      <para>
       <constant>0</constant>: progressive; <constant>1</constant>: interlaced with top field displayed first and top field stored first;
       <constant>2</constant>: undetermined field order; <constant>6</constant>: interlaced with bottom field displayed first and bottom
       field stored first; <constant>9</constant>: interlaced with bottom field displayed first and top field stored first;
       <constant>14</constant>: interlaced with top field displayed first and bottom field stored first
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--stereo-mode</option> <parameter>TID:n|keyword</parameter></term>
     <listitem>
      <para>
       Sets the stereo mode for the video track with the track ID <parameter>TID</parameter>.  The mode can either be a number
       <parameter>n</parameter> between <constant>0</constant> and <constant>14</constant> or one of these keywords:
      </para>

      <para>
       '<literal>mono</literal>', '<literal>side_by_side_left_first</literal>', '<literal>top_bottom_right_first</literal>',
       '<literal>top_bottom_left_first</literal>', '<literal>checkerboard_right_first</literal>',
       '<literal>checkerboard_left_first</literal>', '<literal>row_interleaved_right_first</literal>',
       '<literal>row_interleaved_left_first</literal>', '<literal>column_interleaved_right_first</literal>',
       '<literal>column_interleaved_left_first</literal>', '<literal>anaglyph_cyan_red</literal>',
       '<literal>side_by_side_right_first</literal>', '<literal>anaglyph_green_magenta</literal>',
       '<literal>both_eyes_laced_left_first</literal>', '<literal>both_eyes_laced_right_first</literal>'.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Options that only apply to text subtitle tracks</title>

   <variablelist>
    <varlistentry id="mkvmerge.description.sub_charset">
     <term><option>--sub-charset</option> <parameter>TID:character-set</parameter></term>
     <listitem>
      <para>
       Sets the character set 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 or from Kate
       streams, as these are always stored in UTF-8. See the section about <link linkend="mkvmerge.text_files_and_charsets"> text files and
       character sets</link> for an explanation how &mkvmerge; converts between character sets.
      </para>

      <para>
       This option can be used multiple times for an input file applying to several tracks by selecting different track IDs each time.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

  <refsect2>
   <title>Other options</title>

   <variablelist>
    <varlistentry id="mkvmerge.description.identify">
     <term><option>-i</option>, <option>--identify</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       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.
      </para>

      <para>The output format used for the result can be changed with the option <link linkend="mkvmerge.description.identification_format">--identification-format</link>.</para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.identify_json">
     <term><option>-J</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       This is a convenient alias for "<literal>--identification-format json --identify file-name</literal>".
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.identify_verbose">
     <term><option>-I</option>, <option>--identify-verbose</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       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.
      </para>

      <para>
       The output will also contain properties for all items found, e.g. the file title or the track language.
      </para>

      <note>
       <para>This option is deprecated. It will be removed in 2018.</para>
      </note>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.identification_format">
     <term><option>-F</option>, <option>--identification-format</option> <parameter>format</parameter></term>
     <listitem>
      <para>
       Determines the output format used by the <link linkend="mkvmerge.description.identify"><literal>--identify</literal>
       option</link>. The following formats are supported: <literal>text</literal> (the default if this option isn't used),
       <literal>verbose-text</literal> and <literal>json</literal>.
      </para>

      <orderedlist>
       <listitem>
        <para>The <literal>text</literal> format is short and human-readable. It consists of one line per item found (container, tracks, attachments etc.).</para>

        <para>This format is not meant to be parsed. The output will be translated into the language &mkvmerge; uses (see also <link
        linkend="mkvmerge.description.ui_language">--ui-language</link>).</para>
       </listitem>

       <listitem>
        <para>
         The <literal>verbose-text</literal> format extends the <literal>text</literal> format with additional properties for each item. The
         extra information is surronded by square brackets. It consists of space-saparated key/value pairs where keys and values are separated
         by a colon.
        </para>

        <para>
         Each value is escaped according to the rules described in <link linkend="mkvmerge.escaping">the section about escaping special
         characters in text</link>.
        </para>

        <para>This format is not meant to be parsed. The output will be translated into the language &mkvmerge; uses (see also <link
        linkend="mkvmerge.description.ui_language">--ui-language</link>).</para>

        <note>
         <para>This option is deprecated. It will be removed in 2018.</para>
        </note>
       </listitem>

       <listitem>
        <para>
         The <literal>json</literal> format outputs a machine-readable JSON representation. This format follows the JSON schema described in
         the file <ulink
         url="https://mkvtoolnix.download/doc/mkvmerge-identification-output-schema.json"><literal>mkvmerge-identification-output-schema.json</literal></ulink>.
        </para>
       </listitem>
      </orderedlist>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.probe_range_percentage">
     <term><option>--probe-range-percentage</option> <parameter>percentage</parameter></term>
     <listitem>
      <para>
       File types such as MPEG program and transport streams (<literal>.vob</literal>, <literal>.m2ts</literal>) require parsing a certain
       amount of data in order to detect all tracks contained in the file.  This amount is 0.3% of the source file's size or 10 MB,
       whichever is higher.
      </para>

      <para>
       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.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-l</option>, <option>--list-types</option></term>
     <listitem>
      <para>
       Lists supported input file types.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.list_languages">
     <term><option>--list-languages</option></term>
     <listitem>
      <para>
       Lists all languages and their ISO639-2 code which can be used with the <link
       linkend="mkvmerge.description.language"><option>--language</option></link> option.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--priority</option> <parameter>priority</parameter></term>
     <listitem>
      <para>
       Sets the process priority that &mkvmerge; runs with. Valid values are '<literal>lowest</literal>', '<literal>lower</literal>',
       '<literal>normal</literal>', '<literal>higher</literal>' and '<literal>highest</literal>'. If nothing is given then
       '<literal>normal</literal>' is used. On Unix like systems &mkvmerge; will use the
       <citerefentry><refentrytitle>nice</refentrytitle><manvolnum>2</manvolnum></citerefentry> function. Therefore only the super user can
       use '<literal>higher</literal>' and '<literal>highest</literal>'. On Windows all values are useable for every user.
      </para>

      <para>Selecting '<literal>lowest</literal>' also causes &mkvmerge; to select idle I/O priority in addition to the lowest possible
      process priority.</para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.command_line_charset">
     <term><option>--command-line-charset</option> <parameter>character-set</parameter></term>
     <listitem>
      <para>
       Sets the character set to convert strings given on the command line from. It defaults to the character set given by system's current
       locale. This settings applies to arguments of the following options: <link
       linkend="mkvmerge.description.title"><option>--title</option></link>, <link
       linkend="mkvmerge.description.track_name"><option>--track-name</option></link> and <link
       linkend="mkvmerge.description.attachment_description"><option>--attachment-description</option></link>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.output_charset">
     <term><option>--output-charset</option> <parameter>character-set</parameter></term>
     <listitem>
      <para>
       Sets the character set to which strings are converted that are to be output.  It defaults to the character set given by system's
       current locale.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.redirect_output">
     <term><option>-r</option>, <option>--redirect-output</option> <parameter>file-name</parameter></term>
     <listitem>
      <para>
       Writes all messages to the file <parameter>file-name</parameter> instead of to the console.  While this can be done easily with output
       redirection there are cases in which this option is needed: when the terminal reinterprets the output before writing it to a file.
       The character set set with <link linkend="mkvmerge.description.output_charset"><option>--output-charset</option></link> is honored.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.ui_language">
     <term><option>--ui-language</option> <parameter>code</parameter></term>
     <listitem>
      <para>
       Forces the translations for the language <parameter>code</parameter> to be used (e.g.  '<literal>de_DE</literal>' for the German
       translations). Entering '<literal>list</literal>' as the <parameter>code</parameter> will cause the program to output a list of
       available translations.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.debug">
     <term><option>--debug</option> <parameter>topic</parameter></term>
     <listitem>
      <para>
       Turn on debugging for a specific feature. This option is only useful for developers.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.engage">
     <term><option>--engage</option> <parameter>feature</parameter></term>
     <listitem>
      <para>
       Turn on experimental features. A list of available features can be requested with <command>mkvmerge --engage list</command>. These
       features are not meant to be used in normal situations.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="mkvmerge.description.gui_mode">
     <term><option>--gui-mode</option></term>
     <listitem>
      <para>
       Turns on GUI mode. In this mode specially-formatted lines may be output that can tell a controlling GUI what's happening. These
       messages follow the format '<literal>#GUI#message</literal>'. The message may be followed by key/value pairs as in
       '<literal>#GUI#message#key1=value1#key2=value2…</literal>'. Neither the messages nor the keys are ever translated and always output
       in English.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>@</option><parameter>options-file.json</parameter></term>
     <listitem>
      <para>
       Reads additional command line arguments from the file <parameter>options-file</parameter>. See the section about <link
       linkend="mkvmerge.option_files">option files</link> for further information.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--capabilities</option></term>
     <listitem>
      <para>
       Lists information about optional features that have been compiled in and exit. The first line output will be the version
       information. All following lines contain exactly one word whose presence indicates that the feature has been compiled in. These
       features are:
      </para>

      <itemizedlist>
       <listitem>
        <para>
         '<literal>FLAC</literal>' -- reading raw <abbrev>FLAC</abbrev> files and handling <abbrev>FLAC</abbrev> tracks in other containers,
         e.g. <productname>Ogg</productname> or &matroska;.
        </para>
       </listitem>
      </itemizedlist>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-h</option>, <option>--help</option></term>
     <listitem>
      <para>
       Show usage information and exit.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-V</option>, <option>--version</option></term>
     <listitem>
      <para>
       Show version information and exit.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>--check-for-updates</option></term>
     <listitem>
      <para>
       Checks online for new releases by downloading the URL <ulink
       url="http://mkvtoolnix-releases.bunkus.org/latest-release.xml">http://mkvtoolnix-releases.bunkus.org/latest-release.xml</ulink>. Four
       lines will be output in <literal>key=value</literal> style: the URL from where the information was retrieved (key
       <literal>version_check_url</literal>), the currently running version (key <literal>running_version</literal>), the latest release's
       version (key <literal>available_version</literal>) and the download URL (key <literal>download_url</literal>).
      </para>

      <para>
       Afterwards the program exists with an exit code of 0 if no newer release is available, with 1 if a newer release is available and with
       2 if an error occured (e.g. if the update information could not be retrieved).
      </para>

      <para>
       This option is only available if the program was built with support for libcurl.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>
 </refsect1>

 <refsect1 id="mkvmerge.usage">
  <title>Usage</title>
  <para>
   For each file the user can select which tracks &mkvmerge; should take.  They are all put into the file specified with
   <option>-o</option>. A list of known (and supported) source formats can be obtained with the <option>-l</option> option.
  </para>

  <important>
   <para>
    The order of command line options is important. Please read the section <link linkend="mkvmerge.option_order">&quot;Option
    order&quot;</link> if you're new to the program.
   </para>
  </important>
 </refsect1>

 <refsect1 id="mkvmerge.option_order">
  <title>Option order</title>

  <para>
   The order in which options are entered is important for some options. Options fall into two categories:
  </para>

  <orderedlist>
   <listitem>
    <para>
     Options that affect the whole program and are not tied to any input file. These include but are not limited to
     <option>--command-line-charset</option>, <option>--output</option> or <option>--title</option>. These can appear anywhere on the
     command line.
    </para>
   </listitem>

   <listitem>
    <para>
     Options that affect a single input file or a single track in an input file. These options all apply to the following input file on the
     command line. All options applying to the same input (or to tracks from the same input file) file can be written in any order as long
     as they all appear before that input file's name. Examples for options applying to an input file are <option>--no-chapters</option> or
     <option>--chapter-charset</option>. Examples for options applying to a single track are <option>--default-duration</option> or
     <option>--language</option>.
    </para>
   </listitem>
  </orderedlist>

  <para>
   The options are processed from left to right. If an option appears multiple times within the same scope then the last occurence will be
   used. Therefore the title will be set to &quot;Something else&quot; in the following example:
  </para>

  <screen>$ mkvmerge -o output.mkv --title 'This and that' input.avi --title 'Something else'</screen>

  <para>
   The following example shows that using the <option>--language</option> option twice is OK because they're used in different scopes. Even
   though they apply to the same track ID they apply to different input files and therefore have different scopes:
  </para>

  <screen>$ mkvmerge -o output.mkv --language 0:fre français.ogg --language 0:deu deutsch.ogg</screen>
 </refsect1>

 <refsect1 id="mkvmerge.examples">
  <title>Examples</title>
  <para>
   Let's assume you have a file called MyMovie.avi and the audio track in a separate file, e.g. '<literal>MyMovie.wav</literal>'. First you
   want to encode the audio to &oggvorbis;:
  </para>

  <screen>$ oggenc -q4 -oMyMovie.ogg MyMovie.wav</screen>

  <para>
   After a couple of minutes you can join video and audio:
  </para>

  <screen>$ mkvmerge -o MyMovie-with-sound.mkv MyMovie.avi MyMovie.ogg</screen>

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

  <screen>$ mkvmerge -o MyMovie-with-sound.mkv -A MyMovie.avi MyMovie.ogg</screen>

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

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

  <para>
   The same result can be achieved with
  </para>

  <screen>$ mkvmerge -o MM-complete.mkv -A MyMovie.avi MyMovie.ogg MyMovie-add-audio.ogg</screen>

  <para>
   Now fire up <productname>mplayer</productname> and enjoy. If you have multiple audio tracks (or even video tracks) then you can tell
   <productname>mplayer</productname> which track to play with the '<option>-vid</option>' and '<option>-aid</option>' options. These are
   0-based and do not distinguish between video and audio.
  </para>

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

  <screen>$ mkvmerge --identify outofsync.ogg</screen>

  <para>
   Now you can use that ID in the following command line:
  </para>

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

  <para>
   This would add 200ms of silence at the beginning of the audio track with the
   ID <constant>12345</constant> taken from '<literal>outofsync.ogg</literal>'.
  </para>

  <para>
   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 <constant>0.2</constant> seconds out of sync at the end of the movie which was
   <constant>77340</constant> frames long. At <constant>29.97fps</constant> <constant>0.2</constant> seconds correspond to
   approx. <constant>6</constant> frames. So I did
  </para>

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

  <para>
   The result was fine.
  </para>

  <para>
   The sync options can also be used for subtitles in the same manner.
  </para>

  <para>
   For text subtitles you can either use some Windows software (like <productname>SubRipper</productname>) or the
   <productname>subrip</productname> package found in
   <citerefentry><refentrytitle>transcode</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s sources in the
   '<literal>contrib/subrip</literal>' directory. The general process is:
  </para>

  <orderedlist>
   <listitem>
    <para>extract a raw subtitle stream from the source:</para>
    <screen>$ tccat -i /path/to/copied/dvd/ -T 1 -L | tcextract -x ps1 -t vob -a 0x20 | subtitle2pgm -o mymovie</screen>
   </listitem>

   <listitem>
    <para>convert the resulting PGM images to text with gocr:</para>
    <screen>$ pgm2txt mymovie</screen>
   </listitem>

   <listitem>
    <para>spell-check the resulting text files:</para>
    <screen>$ ispell -d american *txt</screen>
   </listitem>

   <listitem>
    <para>convert the text files to a SRT file:</para>
    <screen>$ srttool -s -w -i mymovie.srtx -o mymovie.srt</screen>
   </listitem>
  </orderedlist>

  <para>
   The resulting file can be used as another input file for &mkvmerge;:
  </para>

  <screen>$ mkvmerge -o mymovie.mkv mymovie.avi mymovie.srt</screen>

  <para>
   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:
  </para>

  <screen>$ mkvmerge --list-languages</screen>

  <para>
   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
  </para>

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

  <para>
   As you can see you can use the <link linkend="mkvmerge.description.language"><option>--language</option></link> switch multiple times.
  </para>

  <para>
   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
  </para>

  <screen>$ 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</screen>

  <para>
   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 <link linkend="mkvmerge.default_values">default values</link>.
  </para>

  <para>
   Turn off the compression for an input file.
  </para>

  <screen>$ mkvmerge -o no-compression.mkv --compression -1:none MyMovie.avi --compression -1:none mymovie.srt</screen>

 </refsect1>

 <refsect1 id="mkvmerge.track_ids">
  <title>Track IDs</title>

  <para>
   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 <link
   linkend="mkvmerge.description.identify"><option>--identify</option></link> option.  An example for such output:
  </para>

  <screen>$ mkvmerge -i v.mkv
File 'v.mkv': container: &matroska;
Track ID 0: video (V_MS/VFW/FOURCC, DIV3)
Track ID 1: audio (A_MPEG/L3)</screen>

  <para>
   Do not confuse the track IDs that are assigned to the tracks that are placed in the output MKV file with the track IDs of the input
   files. Only the input file track IDs are used for options needing these values.
  </para>

  <para>
   Also note that each input file has its own set of track IDs. Therefore the track IDs for file '<filename>file1.ext</filename>' as
   reported by '<literal>mkvmerge --identify</literal>' do not change no matter how many other input files are there or in which position
   '<filename>file1.ext</filename>' is used.
  </para>

  <para>
   Track IDs are assigned like this:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     <abbrev>AVI</abbrev> files: The video track has the ID 0. The audio tracks get IDs in ascending order starting at 1.
    </para>
   </listitem>

   <listitem>
    <para>
     <abbrev>AAC</abbrev>, <abbrev>AC-3</abbrev>, <abbrev>MP3</abbrev>, <abbrev>SRT</abbrev> and <abbrev>WAV</abbrev> files: The one 'track'
     in that file gets the ID 0.
    </para>
   </listitem>

   <listitem>
    <para>
     Most other files: The track IDs are assigned in order the tracks are found in the file starting at 0.
    </para>
   </listitem>
  </itemizedlist>

  <para>
   The special track ID '<constant>-1</constant>' is a wild card and applies the given switch to all tracks that are read from an input
   file.
  </para>

  <para>
   The options that use the track IDs are the ones whose description contains '<literal>TID</literal>'.  The following options use track IDs
   as well: <option>--audio-tracks</option>, <option>--video-tracks</option>, <option>--subtitle-tracks</option>,
   <option>--button-tracks</option> and <option>--track-tags</option>.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.text_files_and_charsets">
  <title>Text files and character set conversions</title>
  <note>
   <para>
    This section applies to all programs in MKVToolNix even if it only mentions &mkvmerge;.
   </para>
  </note>

  <refsect2 id="mkvmerge.text_files_and_charsets.introduction">
   <title>Introduction</title>
   <para>
    All text in a &matroska; file is encoded in UTF-8. This means that &mkvmerge; has to convert every text file it reads as well as every
    text given on the command line from one character set into UTF-8. In return this also means that &mkvmerge;'s output has to be converted
    back to that character set from UTF-8, e.g. if a non-English translation is used with <link
    linkend="mkvmerge.description.ui_language"><option>--ui-language</option></link> or for text originating from a &matroska; file.
   </para>

   <para>
    &mkvmerge; does this conversion automatically based on the presence of a <foreignphrase>byte order marker</foreignphrase> (short:
    <abbrev>BOM</abbrev>) or the system's current locale. How the character set is inferred from the locale depends on the operating system
    that &mkvmerge; is run on.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.text_files_and_charsets.byte_order_markers">
   <title>Byte order markers (BOM)</title>

   <para>
    Text files that start with a BOM are already encoded in one representation of UTF. &mkvmerge; supports the following five modes: UTF-8,
    UTF-16 Little and Big Endian, UTF-32 Little and Big Endian. Text files with a BOM are automatically converted to UTF-8. Any of the
    parameters that would otherwise set the character set for such a file (e.g. <link
    linkend="mkvmerge.description.sub_charset"><option>--sub-charset</option></link>) is silently ignored.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.text_files_and_charsets.unix">
   <title>Linux and Unix-like systems including Mac OS</title>

   <para>
    On Unix-like systems &mkvmerge; uses the <citerefentry><refentrytitle>setlocale</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    system call which in turn uses the environment variables <varname>LANG</varname>, <varname>LC_ALL</varname> and
    <varname>LC_CYPE</varname>. The resulting character set is often one of UTF-8 or the ISO-8859-* family and is used for all text file
    operations and for encoding strings on the command line and for output to the console.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.text_files_and_charsets.windows">
   <title>Windows</title>

   <para>
    On Windows the default character set used for converting text files is determined by a call to the <function>GetACP()</function> system
    call.
   </para>

   <para>
    Reading the command line is done with the <function>GetCommandLineW()</function> function which already returns a Unicode
    string. Therefore the option <option>--command-line-charset</option> is ignored on Windows.
   </para>

   <para>
    Output to the console consists of three scenarios:
   </para>

   <orderedlist>
    <listitem>
     <para>
      If the output is redirected with the option <link
      linkend="mkvmerge.description.redirect_output"><option>--redirect-output</option></link> then the default charset is UTF-8. This can
      be changed with <link linkend="mkvmerge.description.output_charset"><option>--output-charset</option></link>.
     </para>

     <para>
      If the output is redirected with <command>cmd.exe</command> itself, e.g. with <literal>mkvinfo file.mkv &gt; info.txt</literal>, then
      the charset is always UTF-8 and cannot be changed.
     </para>

     <para>
      Otherwise (when writing directly to the console) the Windows function <function>WriteConsoleW()</function> is used and the option
      <link linkend="mkvmerge.description.output_charset"><option>--output-charset</option></link> is ignored. The console should be able to
      output all Unicode characters for which the corresponding language support is installed (e.g. Chinese characters might not be
      displayed on English Windows versions).
     </para>
    </listitem>
   </orderedlist>
  </refsect2>

  <refsect2 id="mkvmerge.text_files_and_charsets.options">
   <title>Command line options</title>

   <para>
    The following options exist that allow specifying the character sets:
   </para>

   <itemizedlist>
    <listitem>
     <para>
      <link linkend="mkvmerge.description.sub_charset"><option>--sub-charset</option></link> for text subtitle files and for text subtitle
      tracks stored in container formats for which the character set cannot be determined unambiguously (e.g. Ogg files),
     </para>
    </listitem>

    <listitem>
     <para>
      <link linkend="mkvmerge.description.chapter_charset"><option>--chapter-charset</option></link> for chapter text files and for chapters
      and file titles stored in container formats for which the character set cannot be determined unambiguously (e.g. Ogg files for chapter
      information, track and file titles etc; MP4 files for chapter information),
     </para>
    </listitem>

    <listitem>
     <para>
      <link linkend="mkvmerge.description.command_line_charset"><option>--command-line-charset</option></link> for all strings on the command
      line,
     </para>
    </listitem>

    <listitem>
     <para>
      <link linkend="mkvmerge.description.output_charset"><option>--output-charset</option></link> for all strings written to the console or
      to a file if the output has been redirected with the <link
      linkend="mkvmerge.description.redirect_output"><option>--redirect-output</option></link> option. On non-Windows systems the default for
      the output charset is the system's current charset. On Windows it defaults to UTF-8 both for redirecting with <link
      linkend="mkvmerge.description.redirect_output"><option>--redirect-output</option></link> and with <command>cmd.exe</command> itself,
      e.g. <literal>mkvinfo file.mkv &gt; info.txt</literal>.
     </para>
    </listitem>
   </itemizedlist>
  </refsect2>
 </refsect1>

 <refsect1 id="mkvmerge.option_files">
  <title>Option files</title>

  <para>
   An option file is a file &mkvmerge; can read additional command line arguments from. This can be used in order to circumvent certain
   limitations of the shell or the operating system when executing external programs like a limited command line length.
  </para>

  <para>
   There are two formats for option files: a JSON format and a proprietary legacy format. The legacy format is deprecated, and support for
   it will likely be removed in 2018.
  </para>

  <refsect2 id="mkvmerge.option_files.json_format">
   <title>The JSON format</title>

   <para>
    A JSON option file's name must end in '<filename>.json</filename>'. Its content must be a valid JSON array consisting solely of JSON
    strings. The file's encoding must be UTF-8. The file should not start with a <foreignphrase>byte order marker</foreignphrase>
    (<abbrev>BOM</abbrev>), but if one exists, it will be skipped.
   </para>

   <para>
    The rules for escaping special characters inside JSON are the ones in the official JSON specification, <ulink url="https://tools.ietf.org/html/rfc7159">RFC 7159</ulink>.
   </para>

   <para>
    The command line '<command>mkvmerge -o "my file.mkv" -A "a movie.avi" sound.ogg</command>' could be converted into the following
    JSON option file called e.g. '<filename>options.json</filename>':
   </para>

   <programlisting>[
  "-o",
  "c:\\Matroska\\my file.mkv",
  "--title",
  "#65",
  "-A",
  "a movie.avi",
  "sound.ogg"
]</programlisting>
  </refsect2>

  <refsect2 id="mkvmerge.option_files.legacy_format">
   <title>The legacy format</title>

   <para>
    There are several rules regarding option files. Lines whose first non-whitespace character is a hash mark ('<literal>#</literal>') are
    treated as comments and ignored. White spaces at the start and end of a line will be stripped. Each line must contain exactly one
    option.
   </para>

   <para>
    A line not containing anything is also ignored. An empty argument is represented by the line '<literal>#EMPTY#</literal>'.
   </para>

   <para>
    Several chars can be escaped, e.g. if you need to start a non-comment line with '#'. The rules are described in <link
    linkend="mkvmerge.escaping">the section about escaping text</link>.
   </para>

   <para>
    Note that backslashes must always be escaped. Hash marks ('#') must be escaped if they should not start a comment.
   </para>

   <para>
    The command line '<command>mkvmerge -o "my file.mkv" -A "a movie.avi" sound.ogg</command>' could be converted into the following
    legacy option file called e.g. '<filename>options.txt</filename>':
   </para>

   <programlisting># Write to the file "c:\Matroska\my file.mkv" on Windows.
-o
c:\\Matroska\\my file.mkv
# Set the title to '#65'.
--title
\h65
# Only take the video from "a movie.avi".
-A
a movie.avi
sound.ogg</programlisting>
  </refsect2>

 </refsect1>

 <refsect1 id="mkvmerge.escaping">
  <title>Escaping special chars in text</title>
  <para>
   There are a few places in which special characters in text must or should be escaped. The rules for escaping are simple: each character
   that needs escaping is replaced with a backslash followed by another character.
  </para>

  <para>
   The rules are: ' ' (a space) becomes '\s', '&quot;' (double quotes) becomes '\2', ':' becomes '\c', '#' becomes '\h', '[' becomes '\b', ']' becomes '\B' and '\' (a single backslash) itself becomes '\\'.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.subtitles">
  <title>Subtitles</title>
  <para>
   There are several text and bitmap subtitle formats that can be embedded into &matroska;. Text subtitles must be recoded to UTF-8 so that
   they can be displayed correctly by a player (see the section about <link linkend="mkvmerge.text_files_and_charsets"> text files and
   character sets</link> for an explanation how &mkvmerge; converts between character sets). Kate subtitles are already encoded in UTF-8 and
   do not have to be re-encoded.
  </para>

  <para>
   The following subtitle formats are supported at the moment:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     Subtitle Ripper (SRT) files
    </para>
   </listitem>

   <listitem>
    <para>
     Substation Alpha (SSA) / Advanced Substation Alpha scripts (ASS)
    </para>
   </listitem>

   <listitem>
    <para>
     Universal Subtitle Format (USF) files
    </para>
   </listitem>

   <listitem>
    <para>
     OggKate streams
    </para>
   </listitem>

   <listitem>
    <para>
     VobSub bitmap subtitle files
    </para>
   </listitem>

   <listitem>
    <para>
     PGS bitmap subtitle files as found on BluRay discs
    </para>
   </listitem>
  </itemizedlist>
 </refsect1>

 <refsect1 id="mkvmerge.file_linking">
  <title>File linking</title>
  <para>
   &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 the
   following explanations use the term 'file linking' although 'segment linking' would be more appropriate.
  </para>

  <para>
   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 (short: <abbrev>SID</abbrev>) of the previous/next file into the segment header
   information. &mkvinfo; prints these <abbrev>SIDs</abbrev> if it finds them.
  </para>

  <para>
   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; does not use file linking. If you want that you
   can turn it on with the <option>--link</option> option. This option is only useful if splitting is activated as well.
  </para>

  <para>
   Regardless of whether splitting is active or not the user can tell &mkvmerge; to link the produced files to specific
   <abbrev>SIDs</abbrev>. This is achieved with the options <option>--link-to-previous</option> and <option>--link-to-next</option>.  These
   options accept a segment <abbrev>SID</abbrev> in the format that &mkvinfo; outputs: 16 hexadecimal numbers between
   <constant>0x00</constant> and <constant>0xff</constant> prefixed with '<literal>0x</literal>' each, e.g. '<code>0x41 0xda 0x73 0x66
   0xd9 0xcf 0xb2 0x1e 0xae 0x78 0xeb 0xb4 0x5e 0xca 0xb3 0x93</code>'. Alternatively a shorter form can be used: 16 hexadecimal numbers
   between <constant>0x00</constant> and <constant>0xff</constant> without the '<literal>0x</literal>' prefixes and without the spaces, e.g.
   '<code>41da7366d9cfb21eae78ebb45ecab393</code>'.
  </para>

  <para>
   If splitting is used then the first file is linked to the <abbrev>SID</abbrev> given with <option>--link-to-previous</option> and the
   last file is linked to the <abbrev>SID</abbrev> given with <option>--link-to-next</option>. If splitting is not used then the one output
   file will be linked to both of the two <abbrev>SIDs</abbrev>.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.default_values">
  <title>Default values</title>
  <para>
   The &matroska; specification states 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
   <parameter>language</parameter> and the <parameter>default track flag</parameter> elements.  The default value for the
   <parameter>language</parameter> is English ('<literal>eng</literal>'), and the default value for the <parameter>default track
   flag</parameter> is <parameter>true</parameter>. Therefore if you used <option>--language 0:eng</option> for a track then it will not
   show up in &mkvinfo;'s output.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.attachments">
  <title>Attachments</title>
  <para>
   Maybe you also want to keep some photos along with your &matroska; file, or you're using <abbrev>SSA</abbrev> subtitles and need a
   special <productname>TrueType</productname> 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 '<productname>TrueType</productname> fonts' case).
  </para>

  <para>
   Here's an example how to attach a photo and a <productname>TrueType</productname> font to the output file:
  </para>

  <screen>$ 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-mime-type application/octet-stream \
  --attach-file really_cool_font.ttf</screen>

  <para>
   If a &matroska; containing attachments file is used as an input file then &mkvmerge; will copy the attachments into the new file. The
   selection which attachments are copied and which are not can be changed with the options <link
   linkend="mkvmerge.description.attachments"><option>--attachments</option></link> and <link
   linkend="mkvmerge.description.no_attachments"><option>--no-attachments</option></link>.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.chapters">
  <title>Chapters</title>
  <para>
   The &matroska; chapter system is more powerful than the old known system used by <abbrev>OGM</abbrev> files. The full specifications can
   be found at <ulink url="http://www.matroska.org/">the &matroska; website</ulink>.
  </para>

  <para>
   &mkvmerge; supports two kinds of chapter files as its input. The first format, called '<foreignphrase>simple chapter
   format</foreignphrase>', is the same format that the <abbrev>OGM</abbrev> tools expect. The second format is a &xml; based
   chapter format which supports all of &matroska;'s chapter functionality.
  </para>

  <refsect2 id="mkvmerge.chapters.simple">
   <title>The simple chapter format</title>

   <para>
    This formmat consists of pairs of lines that start with '<literal>CHAPTERxx=</literal>' and '<literal>CHAPTERxxNAME=</literal>'
    respectively. The first one contains the start timecode while the second one contains the title. Here's an example:
   </para>

   <screen>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</screen>

   <para>
    &mkvmerge; will transform every pair or lines into one &matroska; <classname>ChapterAtom</classname>. It does not set any
    <classname>ChapterTrackNumber</classname> which means that the chapters all apply to all tracks in the file.
   </para>

   <para>
    As this is a text file character set conversion may need to be done. See the section about <link
    linkend="mkvmerge.text_files_and_charsets"> text files and character sets</link> for an explanation how &mkvmerge; converts between
    character sets.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.chapters.xml">
   <title>The &xml; based chapter format</title>
   <para>
    The &xml; based chapter format looks like this example:
   </para>

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

   <para>
    With this format three things are possible that are not possible with the simple chapter format:
   </para>

   <orderedlist>
    <listitem><para>The timestamp for the end of the chapter can be set,</para></listitem>
    <listitem><para>chapters can be nested,</para></listitem>
    <listitem><para>the language and country can be set.</para></listitem>
   </orderedlist>

   <para>
    The mkvtoolnix distribution contains some sample files in the <filename>doc</filename> subdirectory which can be used as a basis.
   </para>

   <para>
    The following lists the supported XML tags, their data types and, where appropriate, the valid range for their values:
   </para>

   <screen>Chapters (master)
  EditionEntry (master)
    EditionUID (unsigned integer, valid range: 1 &lt;= value)
    EditionFlagHidden (unsigned integer, valid range: 0 &lt;= value &lt;= 1)
    EditionFlagDefault (unsigned integer, valid range: 0 &lt;= value &lt;= 1)
    EditionFlagOrdered (unsigned integer, valid range: 0 &lt;= value &lt;= 1)
    ChapterAtom (master)
      ChapterAtom (master)
      ChapterUID (unsigned integer, valid range: 1 &lt;= value)
      ChapterTimeStart (unsigned integer)
      ChapterTimeEnd (unsigned integer)
      ChapterFlagHidden (unsigned integer, valid range: 0 &lt;= value &lt;= 1)
      ChapterFlagEnabled (unsigned integer, valid range: 0 &lt;= value &lt;= 1)
      ChapterSegmentUID (binary, valid range: 1 &lt;= length in bytes)
      ChapterSegmentEditionUID (unsigned integer, valid range: 1 &lt;= value)
      ChapterPhysicalEquiv (unsigned integer)
      ChapterTrack (master)
        ChapterTrackNumber (unsigned integer, valid range: 1 &lt;= 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)</screen>
  </refsect2>

  <refsect2>
   <title>General notes</title>
   <para>
    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.
   </para>

   <para>
    &mkvmerge; is able to copy chapters from &matroska; source files unless this is explicitly disabled with the <link
    linkend="mkvmerge.description.no_chapters"><option>--no-chapters</option></link> option. The chapters from all sources (&matroska; files,
    Ogg files, <abbrev>MP4</abbrev> files, chapter text files) are usually not merged but end up in separate
    <classname>ChapterEditions</classname>. Only if chapters are read from several &matroska; or &xml; files that share the
    same edition UIDs will chapters be merged into a single <classname>ChapterEdition</classname>. If such a merge is desired in other
    situations as well then the user has to extract the chapters from all sources with &mkvextract; first, merge the &xml;
    files manually and mux them afterwards.
   </para>
  </refsect2>
 </refsect1>

 <refsect1 id="mkvmerge.tags">
  <title>Tags</title>

  <refsect2>
   <title>Introduction</title>

   <para>
    &matroska; supports an extensive set of tags that is deprecated and a new, simpler system like it is is used in most other containers:
    <parameter>KEY=VALUE</parameter>. However, in &matroska; these tags can also be nested, and both the <parameter>KEY</parameter> and the
    <parameter>VALUE</parameter> are elements of their own. The example file <filename>example-tags-2.xml</filename> shows how to use this
    new system.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.tags.scope">
   <title>Scope of the tags</title>

   <para>
    &matroska; tags do not automatically apply to the complete file. They can, but they also may 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 <ulink
    url="http://matroska.org/technical/specs/index.html">the &matroska; specification</ulink> gives more details about this fact.
   </para>

   <para>
    One important fact is that tags are linked to tracks or chapters with the <classname>Targets</classname> &matroska; tag element, and
    that the UIDs used for this linking are <emphasis>not</emphasis> 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;.
   </para>

   <para>
    &mkvmerge; knows two options with which you can add tags to &matroska; files: The <link
    linkend="mkvmerge.description.global_tags"><option>--global-tags</option></link> and the <link
    linkend="mkvmerge.description.tags"><option>--tags</option></link> options. The difference is that the former option, <link
    linkend="mkvmerge.description.global_tags"><option>--global-tags</option></link>, will make the tags apply to the complete file by
    removing any of those <classname>Targets</classname> elements mentioned above.  The latter option, <link
    linkend="mkvmerge.description.tags"><option>--tags</option></link>, automatically inserts the UID that &mkvmerge; generates for the tag
    specified with the <parameter>TID</parameter> part of the <link linkend="mkvmerge.description.tags"><option>--tags</option></link>
    option.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.tags.example">
   <title>Example</title>
   <para>
    Let's say that you want to add tags to a video track read from an <abbrev>AVI</abbrev>. <command>mkvmerge --identify file.avi</command>
    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 all
    <classname>Targets</classname> elements and call &mkvmerge;:
   </para>

   <screen>$ mkvmerge -o file.mkv --tags 0:tags.xml file.avi</screen>
  </refsect2>

  <refsect2 id="mkvmerge.tags.file_format">
   <title>Tag file format</title>
   <para>
    &mkvmerge; supports a &xml; based tag file format. The format is very closely modeled after <ulink
    url="http://matroska.org/technical/specs/index.html">the &matroska; specification</ulink>. Both the binary and the source distributions
    of MKVToolNix come with a sample file called <filename>example-tags-2.xml</filename> which simply lists all known tags and which can be
    used as a basis for real life tag files.
   </para>

   <para>
    The basics are:
   </para>

   <itemizedlist>
    <listitem><para>The outermost element must be <classname>&lt;Tags&gt;</classname>.</para></listitem>
    <listitem>
     <para>One logical tag is contained inside one pair of <classname>&lt;Tag&gt;</classname> &xml; tags.</para>
    </listitem>
    <listitem><para>White spaces directly before and after tag contents are ignored.</para></listitem>
   </itemizedlist>
  </refsect2>

  <refsect2 id="mkvmerge.tags.data_types">
   <title>Data types</title>
   <para>
    The new &matroska; tagging system only knows two data types, a UTF-8 string and a binary type. The first is used for the tag's name and
    the <classname>&lt;String&gt;</classname> element while the binary type is used for the <classname>&lt;Binary&gt;</classname> element.
   </para>

   <para>
    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 '<literal>@</literal>' then the following text is treated as a file name. The corresponding file's content is
    copied into the &matroska; element.
   </para>

   <para>
    Otherwise the data is expected to be <foreignphrase>Base64</foreignphrase> encoded. This is an encoding that transforms binary data into
    a limited set of <abbrev>ASCII</abbrev> characters and is used e.g. in email programs. &mkvextract; will output
    <foreignphrase>Base64</foreignphrase> encoded data for binary elements.
   </para>

   <para>
    The deprecated tagging system knows some more data types which can be found in the official &matroska; tag specs. As &mkvmerge; does not
    support this system anymore these types aren't described here.
   </para>
  </refsect2>

  <refsect2 id="mkvmerge.tags.xml">
   <title>Known tags for the XML file format</title>

   <para>
    The following lists the supported XML tags, their data types and, where appropriate, the valid range for their values:
   </para>

   <screen>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)</screen>
  </refsect2>
 </refsect1>

 <refsect1 id="mkvmerge.segmentinfo">
  <title>The segment info XML files</title>

  <para>
   With a segment info XML file it is possible to set certain values in the &quot;segment information&quot; header field of a &matroska;
   file. All of these values cannot be set via other command line options.
  </para>

  <para>
   Other &quot;segment information&quot; header fields can be set via command line options but not via the XML file. This includes e.g. the
   <option><link linkend="mkvmerge.description.title">--title</link></option> and the <option><link
   linkend="mkvmerge.description.timecode_scale">--timecode-scale</link></option> options.
  </para>

  <para>
   There are other elements that can be set neither via command line options nor via the XML files. These include the following elements:
   <varname>DateUTC</varname> (also known as the &quot;muxing date&quot;), <varname>MuxingApp</varname>, <varname>WritingApp</varname>
   and <varname>Duration</varname>. They're always set by &mkvmerge; itself.
  </para>

   <para>
    The following lists the supported XML tags, their data types and, where appropriate, the valid range for their values:
   </para>

   <screen>Info (master)
  SegmentUID (binary, valid range: length in bytes == 16)
  SegmentFilename (UTF-8 string)
  PreviousSegmentUID (binary, valid range: length in bytes == 16)
  PreviousSegmentFilename (UTF-8 string)
  NextSegmentUID (binary, valid range: length in bytes == 16)
  NextSegmentFilename (UTF-8 string)
  SegmentFamily (binary, valid range: length in bytes == 16)
  ChapterTranslate (master)
    ChapterTranslateEditionUID (unsigned integer)
    ChapterTranslateCodec (unsigned integer)
    ChapterTranslateID (binary)</screen>
 </refsect1>

 <refsect1 id="mkvmerge.file_layout">
  <title>&matroska; file layout</title>
  <para>
   The &matroska; file layout is quite flexible. &mkvmerge; will render a file in a predefined way. The resulting file looks like this:
  </para>

  <para>
   [EBML head] [segment {meta seek #1} [segment information] [track information] {attachments} {chapters} [cluster 1] {cluster 2} ...
   {cluster n} {cues} {meta seek #2} {tags}]
  </para>

  <para>
   The elements in curly braces are optional and depend on the contents and options used. A couple of notes:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     meta seek #1 includes only a small number of level 1 elements, and only if they actually exist: attachments, chapters, cues, tags, meta
     seek #2. Older versions of &mkvmerge; used to put the clusters into this meta seek element as well. Therefore some imprecise guessing
     was necessary to reserve enough space. It often failed. Now only the clusters are stored in meta seek #2, and meta seek #1 refers to
     the meta seek element #2.
    </para>
   </listitem>

   <listitem>
    <para>Attachment, chapter and tag elements are only present if they were added.</para>
   </listitem>
  </itemizedlist>

  <para>
   The shortest possible &matroska; file would look like this:
  </para>

  <para>
   [EBML head] [segment [segment information] [track information] [cluster 1]]
  </para>

  <para>
   This might be the case for audio-only files.
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.external_timecode_files">
  <title>External timecode files</title>
  <para>
   &mkvmerge; allows the user to chose the timecodes for a specific track himself. This can be used in order to create files with variable
   frame rate video or include gaps in audio. A frame in this case is the unit that &mkvmerge; creates separately per &matroska; block. For
   video this is exactly one frame, for audio this is one packet of the specific audio type. E.g. for <abbrev>AC-3</abbrev> this would be a
   packet containing <constant>1536</constant> samples.
  </para>

  <para>
   Timecode files that are used when tracks are appended to each other must only be specified for the first part in a chain of tracks.  For
   example if you append two files, v1.avi and v2.avi, and want to use timecodes then your command line must look something like this:
  </para>

  <screen>$ mkvmerge ... --timecodes 0:my_timecodes.txt v1.avi +v2.avi</screen>

  <para>
   There are four formats that are recognized by &mkvmerge;. The first line always contains the version number. Empty lines, lines
   containing only whitespace and lines beginning with '<literal>#</literal>' are ignored.
  </para>

  <refsect2>
   <title>Timecode file format v1</title>
   <para>
    This format starts with the version line. The second line declares the default number of frames per second.  All following lines contain
    three numbers separated by commas: the start frame (<constant>0</constant> is the first frame), the end frame and the number of frames
    in this range. The <abbrev>FPS</abbrev> is a floating point number with the dot '<literal>.</literal>' as the decimal point. The ranges
    can contain gaps for which the default <abbrev>FPS</abbrev> is used. An example:
   </para>

   <screen># timecode format v1
assume 27.930
800,1000,25
1500,1700,30</screen>
  </refsect2>

  <refsect2>
   <title>Timecode file format v2</title>

   <para>
    In this format each line contains a timecode for the corresponding frame.  This timecode must be given in millisecond precision.  It can
    be a floating point number, but it doesn't have to be.  You <emphasis>have to</emphasis> give at least as many timecode lines as there
    are frames in the track.  The timecodes in this file must be sorted.  Example for 25fps:
   </para>

   <screen># timecode format v2
0
40
80</screen>
  </refsect2>

  <refsect2>
   <title>Timecode file format v3</title>
   <para>
    In this format each line contains a duration in seconds followed by an optional number of frames per second.  Both can be floating point
    numbers.  If the number of frames per second is not present the default one is used.  For audio you should let the codec calculate the
    frame timecodes itself.  For that you should be using <constant>0.0</constant> as the number of frames per second.  You can also create
    gaps in the stream by using the '<literal>gap</literal>' keyword followed by the duration of the gap.  Example for an audio file:
   </para>

   <screen># timecode format v3
assume 0.0
25.325
7.530,38.236
gap, 10.050
2.000,38.236</screen>
  </refsect2>

  <refsect2>
   <title>Timecode file format v4</title>
   <para>
    This format is identical to the v2 format.  The only difference is that the timecodes do not have to be sorted.  This format should
    almost never be used.
   </para>
  </refsect2>
 </refsect1>

 <refsect1 id="mkvmerge.exit_codes">
  <title>Exit codes</title>

  <para>
   &mkvmerge; exits with one of three exit codes:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     <constant>0</constant> -- This exit codes means that muxing has completed successfully.
    </para>
   </listitem>

   <listitem>
    <para>
     <constant>1</constant> -- In this case &mkvmerge; has output at least one warning, but muxing did continue.  A warning is prefixed with
     the text '<literal>Warning:</literal>'.  Depending on the issues involved the resulting file might be ok or not.  The user is urged to
     check both the warning and the resulting file.
    </para>
   </listitem>

   <listitem>
    <para>
     <constant>2</constant> -- This exit code is used after an error occurred.  &mkvmerge; aborts right after outputting the error message.
     Error messages range from wrong command line arguments over read/write errors to broken files.
    </para>
   </listitem>
  </itemizedlist>
 </refsect1>

 <refsect1 id="mkvmerge.environment_variables">
  <title>Environment variables</title>

  <para>
   &mkvmerge; uses the default variables that determine the system's locale (e.g. <varname>LANG</varname> and the <varname>LC_*</varname>
   family). Additional variables:
  </para>

  <variablelist>
   <varlistentry>
    <term><varname>MKVMERGE_DEBUG</varname>, <varname>MKVTOOLNIX_DEBUG</varname> and its short form <varname>MTX_DEBUG</varname></term>
    <listitem>
     <para>The content is treated as if it had been passed via the <link
     linkend="mkvmerge.description.debug"><option>--debug</option></link> option.</para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><varname>MKVMERGE_ENGAGE</varname>, <varname>MKVTOOLNIX_ENGAGE</varname> and its short form <varname>MTX_ENGAGE</varname></term>
    <listitem>
     <para>The content is treated as if it had been passed via the <link
     linkend="mkvmerge.description.engage"><option>--engage</option></link> option.</para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><varname>MKVMERGE_OPTIONS</varname>, <varname>MKVTOOLNIX_OPTIONS</varname> and its short form <varname>MTX_OPTIONS</varname></term>
    <listitem>
     <para>The content is split on white space. The resulting partial strings are treated as if it had been passed as command line
     options. If you need to pass special characters (e.g. spaces) then you have to escape them (see <link linkend="mkvmerge.escaping">the
     section about escaping special characters in text</link>).</para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 id="mkvmerge.seealso">
  <title>See also</title>
  <para>
   &mkvinfo;, &mkvextract;, &mkvpropedit;, &mtxgui;
  </para>
 </refsect1>

 <refsect1 id="mkvmerge.www">
  <title>WWW</title>
  <para>
   The latest version can always be found at <ulink url="https://mkvtoolnix.download/">the MKVToolNix homepage</ulink>.
  </para>
 </refsect1>

</refentry>
