[Libav-user] Problem processing AVI container

Alex Agranovsky alex at sighthound.com
Fri May 22 04:02:07 EEST 2020

I'm seeing a problem with ffmpeg processing an AVI containing H264 
stream. While I can't share the file due to customer's privacy, I 
suspect what the issue might be -- but cannot find any documentation or 
reference code for proper processing.

The issue is that keyframe flag produced in avidec.c is then cleared in 
lavf's utils.c (parse_packet, specifically). The resulting packet stream 
doesn't have any keyframes, rendering the output unplayable. The input 
is playable by both VLC and avidemux.

The offending file has 8-byte long "SxS" chunks after each "00dc", 
"00wb" or "00db" chunk. If ffmpeg processes these, I haven't found where 
-- nor can I find any documentation for this type of chunk. I can't say 
I've ever encountered those before.

Any ideas for possible solutions, workarounds or pointers to relevant 
documentation are greatly appreciated.

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