apac decoder sometimes is not lossless

[ami_stuff]

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%

[Elon Musk]

Do Test more after fix gets into your build.