[FFmpeg-user] Demultiplexing multichannel audio

[Hecken Penner]

Dear everyone!

I am trying to get a script to work which's interesting part grabs a 5.1
audio stream and writes all channels to individual wav-files. Or at least
it is supposed to do so, but I am stuck with an error message that I don't
fully understand. Googling the stuff only leads me to the sources where I
got the advise to do as I did, but maybe one of you guys out there has
tried something similair. The command I want to use is the following:

"ffmpeg -i "$movie" -filter:v
'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]' -map '[FL]'
temp/Left.wav -map '[FR]' temp/Right.wav -map '[FC]' temp/Center.wav -map
'[LFE]' temp/LFE.wav -map '[SL]' temp/SL.wav -map '[SR]' temp/SR.wav"

In fact, as I am on Ubuntu 12.04, I am using avconv instead of ffmpeg
behind the scenes, but I think the syntax should be pretty much the same.
The parsing of the $movie thing also works fine as the output of ffpmeg
says.
Alas, what I get from it is this:

"ffmpeg version N-53724-g716dbc7 Copyright (c) 2000-2013 the FFmpeg
developers
  built on Jun  1 2013 05:26:08 with gcc 4.6 (Debian 4.6.3-1)
  configuration: --prefix=/root/ffmpeg-static/64bit
--extra-cflags='-I/root/ffmpeg-static/64bit/include -static'
--extra-ldflags='-L/root/ffmpeg-static/64bit/lib -static'
--extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared
--disable-ffserver --disable-doc --enable-bzlib --enable-zlib
--enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl
--enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray
--enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex
--enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3
--enable-libvpx
  libavutil      52. 34.100 / 52. 34.100
  libavcodec     55. 12.102 / 55. 12.102
  libavformat    55.  8.102 / 55.  8.102
  libavdevice    55.  2.100 / 55.  2.100
  libavfilter     3. 73.100 /  3. 73.100
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
Input #0, matroska,webm, from 'Room_in_Rome.mkv':
  Metadata:
    creation_time   : 2011-01-28 23:16:53
  Duration: 01:47:27.84, start: 0.000000, bitrate: 5924 kb/s
    Stream #0:0(ger): Video: h264 (High), yuv420p, 1920x816, SAR 1:1 DAR
40:17, 24 fps, 24 tbr, 1k tbn, 48 tbc (default) (forced)
    Metadata:
      title           : QoM Room.in.Rome 1080p
    Stream #0:1(ger): Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536
kb/s (default) (forced)
    Metadata:
      title           : GER-DTS
    Stream #0:2(eng): Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s
    Metadata:
      title           : ENG-DTS
    Stream #0:3(ger): Subtitle: subrip
    Metadata:
      title           : GER-SUBS
    Stream #0:4(ger): Subtitle: subrip (default) (forced)
    Metadata:
      title           : GER-FORCEDSUBS
Output with label 'FL' does not exist in any defined filter graph, or was
already used elsewhere."

I get a very similair message using avconv.

"avconv version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the
Libav developers
  built on Apr  2 2013 17:02:36 with gcc 4.6.3
[matroska,webm @ 0x137e760] max_analyze_duration reached
[matroska,webm @ 0x137e760] Estimating duration from bitrate, this may be
inaccurate
Input #0, matroska,webm, from 'Room_in_Rome.mkv':
  Duration: 01:47:27.84, start: 0.000000, bitrate: 3072 kb/s
    Stream #0.0(ger): Video: h264 (High), yuv420p, 1920x816, PAR 1:1 DAR
40:17, 24 fps, 24 tbr, 1k tbn, 48 tbc (default) (forced)
    Metadata:
      title           : QoM Room.in.Rome 1080p
    Stream #0.1(ger): Audio: dca (DTS), 48000 Hz, 5.1, s16, 1536 kb/s
(default) (forced)
    Metadata:
      title           : GER-DTS
    Stream #0.2(eng): Audio: dca (DTS), 48000 Hz, 5.1, s16, 1536 kb/s
    Metadata:
      title           : ENG-DTS
    Stream #0.3(ger): Subtitle: [0][0][0][0] / 0x0000
    Metadata:
      title           : GER-SUBS
    Stream #0.4(ger): Subtitle: [0][0][0][0] / 0x0000 (default) (forced)
    Metadata:
      title           : GER-FORCEDSUBS
[matroska,webm @ 0x137e760] Invalid stream specifier: [FL].
    Last message repeated 4 times
Stream map '[FL]' matches no streams."

I hope you can make anything of this? I am running out of ideas at this
point.

Regards,
Jakob