[FFmpeg-trac] #5369(undetermined:open): new audiotoolbox encoder does not support AAC encoding with more than 2 channels

[FFmpeg]

#5369: new audiotoolbox encoder does not support AAC encoding with more than 2
channels
-------------------------------------+-------------------------------------
             Reporter:  julian       |                    Owner:  11rcombs
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:               |               Resolution:
  audiotoolbox osx                   |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by julian):

 * owner:   => 11rcombs
 * status:  new => open


Comment:

 even more weird is this - if you convert to two channels it works fine:

 ffmpeg -i test.mkv  -map 0:0 -map 0:1  -vcodec copy -c:a:0 aac -ac:0 2
 -b:a:0 128k  test.mp4

 but if additionally include an AC3 surround copy of the very same
 audiotrack it fails with the audiotoolbox code complaining:


 ffmpeg -i test.mkv  -map 0:0 -map 0:1 -map 0:1 -vcodec copy -c:a:0 aac
 -ac:0 2 -b:a:0 128k  -c:a:1 ac3 -ac:1 6 -b:a:1 448k test.mp4



 full output tested with GIT HEAD from a few seconds ago:

 ffmpeg -i test.mkv  -map 0:0 -map 0:1 -map 0:1 -vcodec copy -c:a:0 aac
 -ac:0 2 -b:a:0 128k  -c:a:1 ac3 -ac:1 6 -b:a:1 448k test.mp4
 ffmpeg version N-79651-ge1c2048 Copyright (c) 2000-2016 the FFmpeg
 developers
   built with Apple LLVM version 7.3.0 (clang-703.0.29)
   configuration: --disable-encoders --disable-muxers --enable-muxer=ac3
 --enable-muxer=mp4 --enable-encoder=aac_at --enable-encoder=ac3 --enable-
 encoder=ac3_fixed --enable-encoder=movtext --enable-muxer=mp3 --disable-
 indev=qtkit --disable-securetransport --disable-network --disable-swscale
 --disable-postproc
   libavutil      55. 22.101 / 55. 22.101
   libavcodec     57. 38.100 / 57. 38.100
   libavformat    57. 34.103 / 57. 34.103
   libavdevice    57.  0.101 / 57.  0.101
   libavfilter     6. 44.100 /  6. 44.100
   libswresample   2.  0.101 /  2.  0.101
 [h264 @ 0x7fb0d3811200] Increasing reorder buffer to 1
 Input #0, matroska,webm, from 'test.mkv':
   Metadata:
     ENCODER         : Lavf55.19.104
   Duration: 00:00:02.08, start: 0.016000, bitrate: 3791 kb/s
     Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709), 1280x718
 [SAR 1:1 DAR 640:359], 23.98 fps, 23.98 tbr, 1k tbn (default)
     Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 384 kb/s
 (default)
     Stream #0:2(eng): Subtitle: subrip
     Metadata:
       title           : CC
       LANGUAGE        : eng
 File 'test.mp4' already exists. Overwrite ? [y/N] y
 [aac_at @ 0x7fb0d401a400] Specified channel layout '5.1' is not supported
 Output #0, mp4, to 'test.mp4':
   Metadata:
     ENCODER         : Lavf55.19.104
     Stream #0:0(eng): Unknown: none, SAR 1:1 DAR 0:0 (default)
     Stream #0:1(eng): Unknown: none (default)
     Metadata:
       LANGUAGE        : eng
       encoder         : Lavc57.38.100 aac_at
     Stream #0:2(eng): Unknown: none (default)
     Metadata:
       LANGUAGE        : eng
       encoder         : Lavc57.38.100 ac3
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
   Stream #0:1 -> #0:1 (ac3 (native) -> aac (aac_at))
   Stream #0:1 -> #0:2 (ac3 (native) -> ac3 (native))
 Error while opening encoder for output stream #0:1 - maybe incorrect
 parameters such as bit_rate, rate, width or height


 but the AC3 surround encoding shouldn't change anything in the
 audiotoolbox track! its still stereo and should still convert!

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5369#comment:4>
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