[FFmpeg-trac] #5343(ffmpeg:new): flac decoding throws "non monotonically increasing dts" error causing audio dropout

[FFmpeg]

#5343: flac decoding throws "non monotonically increasing dts" error causing audio
dropout
--------------------------------+--------------------------------------
             Reporter:  ww4     |                     Type:  defect
               Status:  new     |                 Priority:  normal
            Component:  ffmpeg  |                  Version:  git-master
             Keywords:          |               Blocked By:
             Blocking:          |  Reproduced by developer:  0
Analyzed by developer:  0       |
--------------------------------+--------------------------------------
 I occasionally run across a flac file which decodes with an "Application
 provided invalid, non monotonically increasing dts to muxer" error. This
 error is relatively harmless on some machines, but when I run this on an
 EC2 instance, the decode results in a block of audio silence at the sample
 where the error is pointing.

 Any number of alterations to the exact bits in the encode (lpc_type, minor
 sample alterations, etc.) prevent the decode errors. However, the silent
 block is 100% reproducible on my machine for flac files exhibiting this
 problem.

 Example flac file and corresponding ffmpeg output attached:

 {{{
 $ ~/ffmpeg/ffmpeg -i 5074690822_chol.flac output.wav
 ffmpeg version N-79055-g7725210 Copyright (c) 2000-2016 the FFmpeg
 developers
   built with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
   configuration:
   libavutil      55. 19.100 / 55. 19.100
   libavcodec     57. 28.103 / 57. 28.103
   libavformat    57. 28.102 / 57. 28.102
   libavdevice    57.  0.101 / 57.  0.101
   libavfilter     6. 39.102 /  6. 39.102
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
 Input #0, flac, from '5074690822_chol.flac':
   Metadata:
     MAJOR_BRAND     : qt
     MINOR_VERSION   : 537199360
     COMPATIBLE_BRANDS: qt
     TIMECODE        : 00:59:59:00
     ENCODER         : Lavf56.19.100
   Duration: 00:00:30.00, start: 0.000000, bitrate: 5363 kb/s
     Stream #0:0: Audio: flac, 48000 Hz, 7.1, s32 (24 bit)
 Output #0, wav, to 'output.wav':
   Metadata:
     MAJOR_BRAND     : qt
     MINOR_VERSION   : 537199360
     COMPATIBLE_BRANDS: qt
     ISMP            : 00:59:59:00
     ISFT            : Lavf57.28.102
     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 7.1,
 s16 (24 bit), 6144 kb/s
     Metadata:
       encoder         : Lavc57.28.103 pcm_s16le
 Stream mapping:
   Stream #0:0 -> #0:0 (flac (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 [wav @ 0x3987540] Non-monotonous DTS in output stream 0:0; previous:
 1055232, current: 1041408; changing to 1055232. This may result in
 incorrect timestamps in the output file.
 [wav @ 0x3987540] Non-monotonous DTS in output stream 0:0; previous:
 1055232, current: 1046016; changing to 1055232. This may result in
 incorrect timestamps in the output file.
 [wav @ 0x3987540] Non-monotonous DTS in output stream 0:0; previous:
 1055232, current: 1050624; changing to 1055232. This may result in
 incorrect timestamps in the output file.
 size=   22356kB time=00:00:30.00 bitrate=6104.7kbits/s speed= 109x
 video:0kB audio:22356kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.000533%
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/5343>
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