[FFmpeg-trac] #4904(undetermined:new): Broken vp9 decoding after failed seek in webm file

[FFmpeg]

#4904: Broken vp9 decoding after failed seek in webm file
-------------------------------------+-------------------------------------
               Reporter:  cehoyos    |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:
                Version:  git-       |  undetermined
  master                             |               Keywords:  mkv vp9
             Blocked By:             |  seek
Reproduced by developer:  0          |               Blocking:
                                     |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 (Sample from videolan ticket 15433)
 A vlc user has uploaded a webm vp9 sample that does not allow seeking with
 ffplay. If I try to seek forward ten seconds immediately after starting
 playback, the file continues to play for 66 seconds, then video gets
 broken and does not recover. I was unable to reproduce with {{{ffmpeg}}}.
 {{{
 $ ffplay TestClip\ webm.webm.webm
 ffplay version N-75722-g32a6d37 Copyright (c) 2003-2015 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      55.  2.100 / 55.  2.100
   libavcodec     57.  4.101 / 57.  4.101
   libavformat    57.  2.102 / 57.  2.102
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6.  9.101 /  6.  9.101
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.100 /  2.  0.100
   libpostproc    54.  0.100 / 54.  0.100
 Input #0, matroska,webm, from 'TestClip webm.webm.webm': 0B f=0/0
   Metadata:
     encoder         : Lavf56.40.101
   Duration: 00:03:01.29, start: 0.007000, bitrate: 1722 kb/s
     Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv), 1920x1080, SAR 1:1
 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default)
     Stream #0:1(eng): Audio: opus, 48000 Hz, 5.1, fltp (default)
     Stream #0:2(eng): Subtitle: webvtt (default)
 [matroska,webm @ 0x7fd45c000920] seek_frame_generic failed as this stream
 seems to contain no keyframes after the target timestamp, 1002 non
 keyframes found
 [matroska,webm @ 0x7fd45c000920] seek_frame_generic failed as this stream
 seems to contain no keyframes after the target timestamp, 1002 non
 keyframes found
 TestClip webm.webm.webm: error while seeking
   40.38 A-V:  0.006 fd=   1 aq= 3148KB vq=12213KB sq=    0B
 }}}
 The timecounter shows that FFplay seeks back after playing for 66 seconds
 which fails badly.

 With a different configure line, the issue gets much easier to reproduce:
 Seeking forward produces nearly immediately broken video:
 {{{
 $ ffplay TestClip\ webm.webm.webm
 ffplay version N-75722-g32a6d37 Copyright (c) 2003-2015 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --disable-everything --disable-vdpau --disable-network
 --enable-protocol=file --enable-demuxer=matroska --enable-libopus
 --enable-decoder='vp9,opus' --enable-parser=vp9 --enable-filter=aresample
   libavutil      55.  2.100 / 55.  2.100
   libavcodec     57.  4.100 / 57.  4.100
   libavformat    57.  2.102 / 57.  2.102
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6.  9.101 /  6.  9.101
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.100 /  2.  0.100
 Input #0, matroska,webm, from 'TestClip webm.webm.webm': 0B f=0/0
   Metadata:
     encoder         : Lavf56.40.101
   Duration: 00:03:01.29, start: 0.007000, bitrate: 1722 kb/s
     Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv), 1920x1080, SAR 1:1
 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default)
     Stream #0:1(eng): Audio: opus, 48000 Hz, 5.1, fltp (default)
     Stream #0:2(eng): Subtitle: webvtt (default)
 No codec could be found with id 96265
 [matroska,webm @ 0x7fb258000920] seek_frame_generic failed as this stream
 seems to contain no keyframes after the target timestamp, 1002 non
 keyframes found
 [matroska,webm @ 0x7fb258000920] seek_frame_generic failed as this stream
 seems to contain no keyframes after the target timestamp, 1002 non
 keyframes found
 TestClip webm.webm.webm: error while seeking
   40.12 A-V: -0.001 fd=   1 aq=   69KB vq=  188KB sq=    0B
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4904>
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