Help to create a script to remove audio tracks from MKVs

[mrlyle]

Hi all,

I'm new to this forum. I've been searching for 2 days a way to systematically delete non-english tracks from a hundred MKVs I have, all of them being in the same folder, using a single batch command.
I haven't found it. I know I could do this file by file with MKVToolnix, but it would take me forever.

I want to keep the English audio track along with the English subs, and the other tracks deleted.

I'm using OS X 10.10.3, with a rMBP 13". I have the latest MKVToolnix installed, with MediaInfo.

Here's an example of a MKV I'd like to be processed.

General
Format : Matroska
Format version : Version 2
File size : 3.86 GiB
Duration : 43mn 4s
Overall bit rate mode : Variable
Overall bit rate : 12.8 Mbps
Movie name : LOST S05E01 Bluray 1080p Multi DTS HDMA x264-MAN OF STYLE.mkv
Writing application : HandBrake 0.10.1 2015030800
Writing library : Lavf55.12.0

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 43mn 4s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Writing library : x264 core 142 r2479 dd79a61
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio #1
ID : 2
Format : DTS
Format/Info : Digital Theater Systems
Mode : 16
Format settings, Endianness : Big
Codec ID : A_DTS
Duration : 43mn 4s
Bit rate mode : Constant
Bit rate : 1 509 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Compression mode : Lossy
Stream size : 465 MiB (12%)
Title : Surround
Language : French
Default : Yes
Forced : No

Audio #2
ID : 3
Format : DTS
Format/Info : Digital Theater Systems
Format profile : MA / Core
Mode : 16
Format settings, Endianness : Big
Codec ID : A_DTS
Duration : 43mn 4s
Bit rate mode : Variable
Bit rate : Unknown / 1 509 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Compression mode : Lossless / Lossy
Title : Surround
Language : English
Default : No
Forced : No

Text #1
ID : 4
Format : PGS
Codec ID : S_HDMV/PGS
Codec ID/Info : Picture based subtitle format used on BDs/HD-DVDs
Language : English
Default : No
Forced : No

Text #2
ID : 5
Format : PGS
Codec ID : S_HDMV/PGS
Codec ID/Info : Picture based subtitle format used on BDs/HD-DVDs
Language : French
Default : No
Forced : No

Text #3
ID : 6
Format : PGS
Codec ID : S_HDMV/PGS
Codec ID/Info : Picture based subtitle format used on BDs/HD-DVDs
Language : French
Default : No
Forced : No

Text #4
ID : 7
Format : PGS
Codec ID : S_HDMV/PGS
Codec ID/Info : Picture based subtitle format used on BDs/HD-DVDs
Language : French
Default : No
Forced : No

Menu
00:00:00.000 : :(01)00:00:00:000
00:05:34.000 : :(02)00:05:33:916
00:12:14.734 : :(03)00:12:14:608
00:19:38.886 : :(04)00:19:38:802
00:27:01.119 : :(05)00:27:01:036
00:34:47.293 : :(06)00:34:47:210
00:42:26.794 : :(07)00:42:26:710

Any chance I could perform this easily ? I'm not a power user.

Thanks.

[Baldrick]

Dual boot into windows and try mkvcleaver. .


I haven't seen any other easy batch code for stripping out tracks just by language.

[sneaker]

Create a .bat file with:

md output
for %%a in (*.mkv) do mkvmerge -o "output\%%~na.mkv" --audio-tracks 2 --subtitle-tracks 3 "%%a"

/edit:
Oh, you're not on Windows. I'll let it here to show you the general mkvmerge command, though. Maybe you can adapt it for OS X.

/edit2:
No OS X to test here, but probably something like that:

#!/bin/bash

mkdir "output"

for filename in ./*.mkv
do
     mkvmerge -o "./output/$filename" --audio-tracks 2 --subtitle-tracks 3 "./$filename"
done

[Baldrick]

Does that strip by language? If the mkvs are muxed different. If all are same it would work though.

[sneaker]

It's not by language. If the files have varying track orders the script would have to be vastly more complicated because mkvmerge has no commands to filter input by language. You'd have to do some parsing of mkvmerge --identify-verbose. That said, as long as English is always the second audio as well as the first subtitle track it will work.