Current git master fails to parse some flv files

[Timo R.]

This seems to affect primarily all flv files creates by OBS(​https://obsproject.com/), but as it works fine with 2.8 and earlier versions, it's a regression in ffmpeg.

How to reproduce:

% ./ffprobe ~/Downloads/test.flv 
ffprobe version N-75430-g0cfdaf4 Copyright (c) 2007-2015 the FFmpeg developers
  built with gcc 4.9.3 (Gentoo 4.9.3 p1.1, pie-0.6.2)
  configuration: 
  libavutil      55.  2.100 / 55.  2.100
  libavcodec     57.  3.100 / 57.  3.100
  libavformat    57.  2.100 / 57.  2.100
  libavdevice    57.  0.100 / 57.  0.100
  libavfilter     6.  5.100 /  6.  5.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.100 /  2.  0.100
[flv @ 0x223eba0] Packet mismatch 347 344
[flv @ 0x223eba0] Could not find codec parameters for stream 0 (Video: none, none, 30720 kb/s): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
[flv @ 0x223eba0] Could not find codec parameters for stream 1 (Audio: none, 0 channels, 327 kb/s): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
/home/timo/Downloads/test.flv: End of file

Increasing analyzeduation/probesize does not make any difference.

Sample is attached, and i'm going through a bisect right now, will report back when done.

[Timo R.]

Regression since cbbd906be6150be38dfc14b6bc67dcac8da8aea4

[Michael Niedermayer]

Workaround added in e3cf978cdda91df923e3e5d1f1e66133dbbe6218.
Can you (or someone else) please inform the encoder/muxer authors about this so they can check that their muxer is generating valid files

[r1ch]

Hello,
I'm one of the developers of Open Broadcaster Software. I took a look into our FLV output code and it does seem like we've been writing the wrong tag length when generating FLV files. This will be fixed in our next release. Thanks for bringing this to our attention!