will not play if there is no keyframe in the first frame

assigned to @rbultje

I uploaded a test video

Test video cannot be played on VLC

But Test video can be played on VLC for patched dav1d

I've tested this (on tools/dav1d) before and after the patch, and it plays identically. I think VLC uses the dav1d API slightly differently in a way that causes it to not be able to resume after an error. The issue should probably be fixed there.

Also, ffmpeg plays it correctly for me (using libdav1d):

$ ffmpeg -i ~/Downloads/test.mkv -c:v copy /tmp/test.ivf
ffmpeg version 4.4.1 Copyright (c) 2000-2021 the FFmpeg developers
  built with Apple clang version 13.0.0 (clang-1300.0.29.3)
  configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-librsvg --enable-libtheora --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --enable-zlib --disable-libjack --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-libxcb --disable-libxcb-shm --disable-libxcb-xfixes --disable-indev=jack --enable-opencl --disable-outdev=xv --enable-audiotoolbox --enable-videotoolbox --enable-sdl2 --disable-securetransport --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --enable-libzimg --enable-libdav1d --arch=x86_64 --enable-x86asm --enable-libx265 --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
[libdav1d @ 0x7f9b1801a400] libdav1d 0.9.2
[libdav1d @ 0x7f9b1801a400] Error parsing OBU data
    Last message repeated 150 times
[matroska,webm @ 0x7f9b18008200] decoding for stream 0 failed
[matroska,webm @ 0x7f9b18008200] Could not find codec parameters for stream 0 (Video: av1 (libdav1d) (Main), none(tv, progressive), 512x384): unspecified pixel format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, matroska,webm, from '/Users/ronaldbultje/Downloads/test.mkv':
  Metadata:
    COMPATIBLE_BRANDS: isomiso2mp41
    MAJOR_BRAND     : isom
    MINOR_VERSION   : 512
    ENCODER         : Lavf59.16.100
  Duration: N/A, start: 9.055000, bitrate: N/A
  Stream #0:0: Video: av1 (Main), none(tv, progressive), 512x384, SAR 1:1 DAR 4:3, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      HANDLER_NAME    : VideoHandler
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc59.18.100 libsvtav1
  Stream #0:1: Audio: aac (LC), 44100 Hz, stereo, fltp (default)
    Metadata:
      HANDLER_NAME    : SoundHandler
      VENDOR_ID       : [0][0][0][0]
Output #0, ivf, to '/tmp/test.ivf':
  Metadata:
    COMPATIBLE_BRANDS: isomiso2mp41
    MAJOR_BRAND     : isom
    MINOR_VERSION   : 512
    encoder         : Lavf58.76.100
  Stream #0:0: Video: av1 (Main) (AV01 / 0x31305641), none(tv, progressive), 512x384 [SAR 1:1 DAR 4:3], q=2-31, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      HANDLER_NAME    : VideoHandler
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc59.18.100 libsvtav1
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
[matroska,webm @ 0x7f9b18008200] File ended prematurely0.00 bitrate=N/A speed=   0x    
frame=  669 fps=0.0 q=-1.0 Lsize=    1267kB time=00:00:23.25 bitrate= 446.4kbits/s speed=1.81e+03x    
video:1258kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.729443%

mentioned in merge request !1362 (closed)

We found a bug in FFmpeg which prevented this from working correctly. After 61b104caaa, FFmpeg decodes the provided sample correctly.

I'm not yet sure why VLC fails to play it. It's possible VLC aborts media processing after the first packet decoding error. This is obviously unwanted for live streams. The correct way to resolve this would be to fix VLC, not to workaround the packet decoding errors in dav1d.

I've tried to build VLC myself but I can't get it working. I think the build instructions don't work on Mac 12.0. I would recommend that someone who can build VLC fix their API usage. I think they need to re-try decoding video packets if the first packet fails. I can help further if someone can help me build VLC.

closed

reopened

ffmpeg also doesn't decode correctly

test.webm does play in ffplay for libaom-av1

ffplay -codec:v libaom-av1 -i test.webm

test.webm does not play in ffplay for libdav1d

ffplay -codec:v libdav1d -i test.webm

But test.webm does play in ffplay for patched libdav1d

AV1 Video Extension(using dav1d) also doesn't decode correctly

https://www.microsoft.com/en-us/p/av1-video-extension/9mvzqvxjbq9v

I think it's better to fix Dav1d than VLC

ffmpeg also doesn't decode correctly

Did you try again using an ffmpeg build that includes the fix Ronald talked about, namely commit hash 61b104caaa? It's available in the master branch, and releases 5.0, 4.4, and 4.3 branches.

ffmpeg fixed with 61b104caaa.

Thank you

closed

I think it's better to fix Dav1d than VLC

I don't think we should disable one particular case of error reporting when applications don't use the API correctly. I understand this can be infuriating, but it's better (long-term) to fix the applications.

I got some help building VLC. Bugfix for VLC is here: vlc!1346 (merged)

mentioned in merge request vlc!1346 (merged)

mentioned in merge request vlc!1405 (merged)

See also vlc!1405 (merged) for VLC 3.0.x

changed milestone to %1.0.0

added bug label

will not play if there is no keyframe in the first frame

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