sample/frame number mismatch in adjacent frames

[jimmalone]

Summary of the bug:
sample/frame number mismatch in adjacent frames
This apparently recurring error is still appearing with latest ffmepg 4.2. There's no discernable problem in the sound itself, but this error appears randomly when decoding flac files.

How to reproduce:

ffmpeg -i input.flac output.wav

ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.1.1 (GCC) 20190807
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, flac, from 'input.flac':
  Metadata:
    encoder         : Lavf58.29.100
  Duration: 00:05:38.33, start: 0.000000, bitrate: 300 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, mono, s16
Stream mapping:
  Stream #0:0 -> #0:0 (flac (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, wav, to 'output.wav':
  Metadata:
    ISFT            : Lavf58.29.100
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, mono, s16, 705 kb/s
    Metadata:
      encoder         : Lavc58.54.100 pcm_s16le
[NULL @ 0000017013fdb640] sample/frame number mismatch in adjacent frames
size=   29142kB time=00:05:38.33 bitrate= 705.6kbits/s speed=1.97e+03x
video:0kB audio:29142kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000261%

[jimmalone]

Unable to upload the input.flac file as it is too big. File can be downloaded from here, ​https://randomhouse.box.com/s/cm36axsgxppgdz2nase2xcfz28694nc6

[mkver]

Sample works fine on git master (the only version supported here). See ticket #5937 (searching for your error message would have found this).