[FFmpeg-trac] #7287(avcodec:new): Audiotoolbox decodes 24-bit ALAC as 16-bit

FFmpeg trac at avcodec.org
Thu Jun 28 20:14:35 EEST 2018


#7287: Audiotoolbox decodes 24-bit ALAC as 16-bit
-------------------------------------+-------------------------------------
             Reporter:  macdavis     |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  avcodec      |                  Version:  git-
             Keywords:               |  master
  Audiotoolbox                       |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 The sample file is 24-bit, but Audiotoolbox decodes as 16-bit.

 How to reproduce:
 {{{
 ffmpeg -c:a alac_at -i /Volumes/New\ Volume/Untitledsample_24_bit_alac.m4a
 -f null -
 ffmpeg version 3.4.git Copyright (c) 2000-2018 the FFmpeg developers
   built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
   configuration: --extra-cflags='-Ofast -march=native -m64 -finline-
 functions -funroll-loops -ffunction-sections -fdata-sections -ffp-
 contract=fast' --arch=x86_64 --cpu=haswell --disable-ffplay --disable-
 runtime-cpudetect --disable-debug --disable-opencl --disable-avdevice
 --enable-libfdk-aac --disable-doc --enable-hardcoded-tables
   libavutil      56. 18.102 / 56. 18.102
   libavcodec     58. 20.104 / 58. 20.104
   libavformat    58. 17.101 / 58. 17.101
   libavfilter     7. 25.100 /  7. 25.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Volumes/New
 Volume/Untitledsample_24_bit_alac.m4a':
   Metadata:
     major_brand     : M4A
     minor_version   : 0
     compatible_brands: M4A mp42isom
     creation_time   : 2018-06-28T17:03:28.000000Z
     iTunSMPB        :  00000000 00000000 00001000 0000000000190000
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
   Duration: 00:00:37.24, start: 0.000000, bitrate: 219 kb/s
     Stream #0:0(eng): Audio: alac (alac / 0x63616C61), 44100 Hz, stereo,
 s16, 1246 kb/s (default)
     Metadata:
       creation_time   : 2018-06-28T17:03:28.000000Z
 Stream mapping:
   Stream #0:0 -> #0:0 (alac (alac_at) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 Output #0, null, to 'pipe:':
   Metadata:
     major_brand     : M4A
     minor_version   : 0
     compatible_brands: M4A mp42isom
     iTunSMPB        :  00000000 00000000 00001000 0000000000190000
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
     encoder         : Lavf58.17.101
     Stream #0:0(eng): Audio: pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s
 (default)
     Metadata:
       creation_time   : 2018-06-28T17:03:28.000000Z
       encoder         : Lavc58.20.104 pcm_s16le
 size=N/A time=00:00:07.24 bitrate=N/A speed= 477x
 video:0kB audio:1248kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7287>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


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