[FFmpeg-user] issue with trim & pan filters

[Christian Johannesen]

I ran into an issue with ffmpeg tonight where I could not trim a source
because of the audio channel configuration of the track I was pulling audio
from. The source has a track of 12 channels of audio. I can process the
first two channels in the track to a stereo output with the pan filter. If
I apply a trim to the input - the trim for input stream complains that it
cannot select the channel layout for the link between the filters trim and
the Parsed_pan_0. I have tried adding -guess_layout_max 0 before the input,
and have tried
setting aformat=channel_layouts=FC+FC+FC+FC+FC+FC+FC+FC+FC+FC+FC+FC without
success.

Any suggestions would be appreciated.

Thanks,
Chris

>ffmpeg.exe -r 24000/1001 -ss 00:00:06.256 -t 00:00:20.771 -i
d:\media\1080p2398_timecode_12ch_multitrack.mov -filter_complex
"[0:1]pan=2c|c0=c0c1=c1[pan_0_0]" -map 0:0 -map "[pan_0_0]" -c:v libx264
-c:a aac -shortest d:\media\1080p2398_timecode_clip_stereo.mp4
ffmpeg version N-77528-gf88546b Copyright (c) 2000-2015 the FFmpeg
developers
  built with gcc 5.2.0 (GCC)
  configuration: --enable-gpl --enable-nonfree --enable-libx264
--enable-libx265 --enable-libfdk_aac --enable-static --disable-shared
--enable-libfreetype --enable-libfontconfig
  libavutil      55. 11.100 / 55. 11.100
  libavcodec     57. 20.100 / 57. 20.100
  libavformat    57. 21.100 / 57. 21.100
  libavdevice    57.  0.100 / 57.  0.100
  libavfilter     6. 22.100 /  6. 22.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
'd:\media\1080p2398_timecode_12ch_multitrack.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2015-12-30 03:50:57
    com.apple.quicktime.player.version: 7.6.9 (Dev)
    com.apple.quicktime.version: 7.6.9 (1680.9)
    com.apple.quicktime.player.movie.audio.gain: 1.000000
    com.apple.quicktime.player.movie.audio.treble: 0.000000
    com.apple.quicktime.player.movie.audio.bass: 0.000000
    com.apple.quicktime.player.movie.audio.balance: 0.000000
    com.apple.quicktime.player.movie.audio.pitchshift: 0.000000
    com.apple.quicktime.player.movie.audio.mute:
    com.apple.quicktime.player.movie.visual.brightness: 0.000000
    com.apple.quicktime.player.movie.visual.color: 1.000000
    com.apple.quicktime.player.movie.visual.tint: 0.000000
    com.apple.quicktime.player.movie.visual.contrast: 1.000000
  Duration: 00:00:27.07, start: 0.000000, bitrate: 29785 kb/s
    Stream #0:0(eng): Video: prores (apcs / 0x73637061),
yuv422p10le(bt709), 1920x1080, 15958 kb/s, SAR 1:1 DAR 16:9, 23.98 fps,
23.98 tbr, 24k tbn, 24k tbc (default)
    Metadata:
      creation_time   : 2015-12-30 03:50:57
      handler_name    : Apple Alias Data Handler
      encoder         : Apple ProRes 422 (LT)
      timecode        : 00:59:45:00
    Stream #0:1(eng): Audio: pcm_s24le (lpcm / 0x6D63706C), 48000 Hz, 12
channels, s32 (24 bit), 13824 kb/s (default)
    Metadata:
      creation_time   : 2015-12-30 03:50:57
      handler_name    : Apple Alias Data Handler
      timecode        : 00:59:45:00
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2015-12-30 03:50:57
      handler_name    : Apple Alias Data Handler
      timecode        : 00:59:45:00
[trim for input stream 0:1 @ 000000ecd74caac0] Cannot select channel layout
for the link between filters trim for input stream 0:1 and Parsed_pan_0.
[trim for input stream 0:1 @ 000000ecd74caac0] Unknown channel layouts not
supported, try specifying a channel layout using
'aformat=channel_layouts=something'.
Error configuring complex filters.
Invalid argument