[FFmpeg-trac] #10072(undetermined:new): apac decoder sometimes is not lossless

[FFmpeg]

#10072: apac decoder sometimes is not lossless
-------------------------------------+-------------------------------------
             Reporter:  ami_stuff    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 there is one difference in the output at the end of the file




 33_2.wav - input file used in apac to encode 33_2.APC

 33_2.APC - encoded apac file

 33_2_out_from_apac.WAV - decoded output in apac from 33_3.APC



 the output from

 ./ffmpeg -i 33_2.wav -f s16le -y 33_2.raw

 and

 ./ffmpeg -i 33_2_out_from_apac.WAV -f s16le -y 33_2_out_from_apac.raw

 is the same

 {{{
 ./ffmpeg  -i 33_2.APC -y -f s16le 33_2_ff_apc.raw
 ffmpeg version N-109101-g822da7a317 Copyright (c) 2000-2022 the FFmpeg
 developers
   built with gcc 9 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
   configuration: --enable-libopenjpeg
   libavutil      57. 42.100 / 57. 42.100
   libavcodec     59. 52.102 / 59. 52.102
   libavformat    59. 34.101 / 59. 34.101
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 50.100 /  8. 50.100
   libswscale      6.  8.112 /  6.  8.112
   libswresample   4.  9.100 /  4.  9.100
 Guessed Channel Layout for Input Stream #0.0 : stereo
 Input #0, apac, from '33_2.APC':
   Duration: N/A, bitrate: N/A
   Stream #0:0: Audio: apac, 33333 Hz, 2 channels, s16p
 Stream mapping:
   Stream #0:0 -> #0:0 (apac (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 Output #0, s16le, to '33_2_ff_apc.raw':
   Metadata:
     encoder         : Lavf59.34.101
   Stream #0:0: Audio: pcm_s16le, 33333 Hz, stereo, s16, 1066 kb/s
     Metadata:
       encoder         : Lavc59.52.102 pcm_s16le
 size=    1302kB time=00:00:09.99 bitrate=1066.7kbits/s speed= 193x
 video:0kB audio:1302kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.000000%
 }}}


 {{{
 ./ffmpeg  -i 33_2.wav -y -f s16le 33_2.raw
 ffmpeg version N-109101-g822da7a317 Copyright (c) 2000-2022 the FFmpeg
 developers
   built with gcc 9 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
   configuration: --enable-libopenjpeg
   libavutil      57. 42.100 / 57. 42.100
   libavcodec     59. 52.102 / 59. 52.102
   libavformat    59. 34.101 / 59. 34.101
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 50.100 /  8. 50.100
   libswscale      6.  8.112 /  6.  8.112
   libswresample   4.  9.100 /  4.  9.100
 Guessed Channel Layout for Input Stream #0.0 : stereo
 Input #0, wav, from '33_2.wav':
   Metadata:
     encoder         : Lavf57.83.100
   Duration: 00:00:10.00, bitrate: 1066 kb/s
   Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 33333 Hz, 2
 channels, s16, 1066 kb/s
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 Output #0, s16le, to '33_2.raw':
   Metadata:
     encoder         : Lavf59.34.101
   Stream #0:0: Audio: pcm_s16le, 33333 Hz, stereo, s16, 1066 kb/s
     Metadata:
       encoder         : Lavc59.52.102 pcm_s16le
 size=    1302kB time=00:00:09.98 bitrate=1068.4kbits/s speed= 709x
 video:0kB audio:1302kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.000000%
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10072>
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