mkvdts2ac3

mkvdts2ac3 is a bash script which can be used for converting the DTS in Matroska (MKV) files to AC3. It provides you with a healthy set of options for controlling the resulting file.

Installation

Prerequisites

Make sure the executables for the following libraries are accessible.

1. mkvtoolnix - Matroska tools
   http://www.bunkus.org/videotools/mkvtoolnix/

2. libdca - DTS to WAV decoder
   http://videolan.org/developers/libdca.html

3. aften - WAV to AC3 encoder
   http://aften.sourceforge.net/

Note: If you are a Mac OS X user you may need to compile these libraries.

Installation

If you have git installed, you can just run git clone git://github.com/JakeWharton/mkvdts2ac3.git. Otherwise you can click the "Download" link on the GitHub project page and download an archive and extract its contents.

Optional: If you want easy access to the script from any directory you can copy or symlink the mkvdts2ac3.sh file to a directory in your PATH variable or else append the script's directory to the PATH variable.

Usage

This script was designed to be very simple and will automatically convert the first DTS track it finds in a Matroska file to AC3 and append it when run without any arguments. Since this was the most common scenario for the developer it is the default action.

mkvdts2ac3.sh Some.Random.Movie.mkv

For users who wish to change the behavior there are a variety of options which control various aspects of the script. Here is the output of the --help argument.

mkvdts2ac3-1.0.3 - by Jake Wharton <jakewharton@gmail.com>

Usage: ./mkvdts2ac3.sh [options] <filename>
Options:
     -d, --default    Mark AC3 track as default.
     -e, --external   Leave AC3 track out of file. Does not modify the
                      original matroska file. This overrides '-n' and
                      '-d' arguments.
     -c TITLE,        Custom AC3 track title.
     --custom TITLE
     -k, --keep-dts   Keep external DTS track (implies '-n').
     -n, --no-dts     Do not retain the DTS track.
     -o MODE          Pass a custom audio output mode to libdca.
     -t TRACKID,
     --track TRACKID  Specify alternate DTS track.
     -w FOLDER,
     --wd FOLDER      Specify alternate temporary working directory.

     --test           Print commands only, execute nothing.
     --debug          Print commands and pause before executing each.

     -h, --help       Print command usage.
     -v, --version    Print script version information.

Examples

Keep only the new AC3 track, discarding the original DTS

mkvdts2ac3.sh -n Some.Random.Movie.mkv

Specify an alternate directory to use for the temporary files. This can be useful when the partition your /tmp directory on is tiny.

mkvdts2ac3.sh -w /mnt/bigHDD Some.Random.Movie.mkv

Convert a different DTS track rather than the first one sequentially in the file. This will require you to check the output of a command like mkvmerge -i Some.Random.Movie.mkv which will give you the track ids of each file.

mkvdts2ac3.sh -t 4 Some.Random.Movie.mkv

If you want to retain the DTS track in an alternate location you can instruct the script not to delete it after the conversion.

mkvdts2ac3.sh -k Some.Random.Movie.mkv

If you want to keep the original file untouched (such as if you are still seeding it in a torrent) and your player supports external audio tracks you can choose to leave the converted AC3 track out of the file.

mkvdts2ac3.sh -e Some.Random.Movie.mkv

All of these examples only showcase the use of a single argument but they can be combined to achieve the desired result.

mkvdts2ac3.sh -d -t 3 -w /mnt/media/tmp/ Some.Random.Movie.mkv

If you're unsure of what any command will do run it with the --test argument to display a list of command execute. You can also use the --debug argument which will print out the commands and wait for the user to press the return key before running each.

$ mkvdts2ac3.sh --test -d -t 3 -w /mnt/media/tmp/ Some.Random.Movie.mkv
mkvdts2ac3-1.0.0 - by Jake Wharton <jakewharton@gmail.com>

MKVFILE: Some.Random.Movie.mkv
DTSFILE: /mnt/media/tmp//Some.Random.Movie.dts
AC3FILE: /mnt/media/tmp//Some.Random.Movie.ac3
NEWFILE: /mnt/media/tmp//Some.Random.Movie.new.mkv

Checking to see if DTS track specified via arguments is valid
> mkvmerge -i "Some.Random.Movie.mkv" | grep "Track ID 3: audio (A_DTS)"

Extract language from selected DTS track.
> mkvinfo "Some.Random.Movie.mkv" | grep -A 12 "Track number: 3" | tail -n 1 | cut -d" " -f5

Extract DTS file from MKV.
> mkvextract tracks "Some.Random.Movie.mkv" 3:"/mnt/media/tmp//Some.Random.Movie.dts"

Converting DTS to AC3.
> dcadec -o wavall "/mnt/media/tmp//Some.Random.Movie.dts" | aften - "/mnt/media/tmp//Some.Random.Movie.ac3"

Removing temporary DTS file.
> rm -f "/mnt/media/tmp//Some.Random.Movie.dts"

Running main remux.
> mkvmerge -o "/mnt/media/tmp//Some.Random.Movie.new.mkv" "Some.Random.Movie.mkv" --default-track 0 --language 0:DTSLANG "/mnt/media/tmp//Some.Random.Movie.ac3"

Removing temporary AC3 file.
> rm -f "/mnt/media/tmp//Some.Random.Movie.ac3"

Copying new file over the old one.
> cp "/mnt/media/tmp//Some.Random.Movie.new.mkv" "Some.Random.Movie.mkv"

Remove working file.
> rm -f "/mnt/media/tmp//Some.Random.Movie.new.mkv"

Developed By

• Jake Wharton - jakewharton@gmail.com

Git repository located at github.com/JakeWharton/mkvdts2ac3

Special Thanks

• John Nilsson - Dependency, file, and space checking as well as general bash formatting
• crimsdings - General debugging and error resolution
• Vladimir Berezhnoy - Feature to copy track name from DTS
• Ricardo Capurro - Bug reporting on uncommon uses
• Tom Flanagan - Idea for downmixing support

And to everyone who submitted bug reports through email and on networkedmediatank.com

License

Copyright 2009 Jake Wharton

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.