mkvdts2eac3/mkvtruehd2eac3 is a bash script which can be used for converting the DTS or TRUEHD in Matroska (MKV) files to EAC3. 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
2. ffmpeg - Audio conversion tool
3. rsync - File transfer and synchronization

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

Usage

This script was designed to be very simple and will automatically convert the first DTS or TRUEHD track it finds in a Matroska file to EAC3 and append it when run without any arguments. Since this was the most common scenario for the developer it is the default action. mkvdts2eac3.sh Some.Random.Movie.mkv mkvtruehd2eac3.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.

    Options:
     -c TITLE,        Custom AC3 track title.
     --custom TITLE
     -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.
     -f, --force      Force processing when AC3 track is detected
     -i, --initial    New AC3 track will be first in the file.
     -k, --keep-dts   Keep external DTS track (implies '-n').
     -m, --nocolor    Do not use colors (monotone).
     --md5            Perform MD5 comparison when copying across drives.
     -n, --no-dts     Do not retain the DTS track.
     --new            Do not copy over original. Create new adjacent file.
     -p PRIORITY      Modify niceness of executed commands.
     -s MODE,
     --compress MODE  Apply header compression to streams (See mkvmerge's --compression).
     -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, --verbose    Turn on verbose output
     -V, --version    Print script version information.

User Defaults

If you find yourself constantly using the same settings, you can create a configuration file to automatically set them. Copy the following to ~/.mkvdts2eac3.rc and uncomment whichever lines you wish.

#EXTERNAL=1
#NODTS=1
#KEEPDTS=1
#DEFAULT=1
#FORCE=1
#INITIAL=1
#NOCOLOR=1
#MD5=1
#NEW=1
#PRIORITY=0
#DTSTRACK=
#DTSNAME=
#COMP="none"

(Note: If EXTERNAL is set then NODTS and KEEPDTS should not be used. AUDIOMODE is the -o-flag value passed to aften. PRIORITY is the niceness value. DTSNAME is custom title for new AC3 track.)

Examples

Keep only the new EAC3 track, discarding the original DTS/TRUEHD track

mkvdts2eac3.sh -n Some.Random.Movie.mkv
mkvtruehd2eac3.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
mkvtruehd2ac3.sh -w /mnt/bigHDD Some.Random.Movie.mkv

Convert a different DTS/TRUEHD 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.

mkvdts2eac3.sh -t 4 Some.Random.Movie.mkv
mkvtruehd2eac3.sh -t 4 Some.Random.Movie.mkv

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

mkvdts2eac3.sh -k Some.Random.Movie.mkv
mkvtruehd2eac3.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.

mkvdts2eac3.sh -e Some.Random.Movie.mkv
mkvtruehd2eac3.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.

mkvdts2eac3.sh -d -t 3 -w /mnt/media/tmp/ Some.Random.Movie.mkv
mkvtruehd2eac3.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.

$ ./mkvdts2eac3.sh --test -d -t 3 -w /mnt/media/tmp Some.Random.Movie.mkv
$ ./mkvtruehd2eac3.sh --test -d -t 3 -w /mnt/media/tmp Some.Random.Movie.mkv


MKV FILE: Some.Random.Move.mkv
DTS/TRUE FILE: /mnt/media/tmp/Some.Random.Movie.dts
EAC3 FILE: /mnt/media/tmp/Some.Random.Movie.ac3
TIMECODE: /mnt/media/tmp/Some.Random.Movie.tc
NEW FILE: /mnt/media/tmp/Some.Random.Movie.new.mkv
WORKING DIRECTORY: /mnt/media/tmp
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 track information for selected DTS track.
> mkvinfo "Some.Random.Movie.mkv" | grep -A 25 "Track number: 3"

Extract language from track info.
> echo "INFO" | grep -m 1 "Language" | cut -d " " -f 5

Extract name for selected DTS track. Change DTS to EAC3 and update bitrate if present.
> echo "INFO" | grep -m 1 "Name" | cut -d " " -f 5- | sed "s/DTS/EAC3/" | awk '{gsub(/[0-9]+(\.[0-9]+)?(M|K)bps/,"6144Kbps")}1'

Extract timecode information for the audio track.
> mkvextract timecodes_v2 "Some.Random.Movie.mkv" 3:"/mnt/media/tmp/Some.Random.Movie.tc"
> sed -n "2p" "/mnt/media/tmp/Some.Random.Movie.tc"
> rm -f "/mnt/media/tmp/Some.Random.Movie.tc"

Extract DTS file from MKV.
> mkvextract tracks "Some.Random.Movie.mkv" 3:"/mnt/media/tmp/Some.Random.Movie.dts"
Converting DTS to EAC3.
> ffmpeg -i "/mnt/media/tmp/Some.Random.Movie.dts" -acodec eac3 -ac 6 -ab 6144k "/mnt/media/tmp/Some.Random.Movie.eac3"

Running main remux.
> nice -n 0 mkvmerge -q -o "/mnt/media/tmp/Some.Random.Movie.new.mkv" --compression 1:none "Some.Random.Movie.mkv" --default-track 0 --language     0:DTSLANG --track-name 0:"DTSNAME" --sync 0:DELAY --compression 0:none "/mnt/media/tmp/Some.Random.Movie.ac3"
Removing temporary AC3 file.
> rm -f "/mnt/media/tmp/Some.Random.Movie.eac3"

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"