[Ffmpeg-devel] avi out is buggy

Thomas Herrmann ollo.diab
Mon May 9 12:08:12 CEST 2005


it seems the avi output of ffmpeg is buggy in the way that AC3 sound gets
out of sync over time. The sound just drifts apart from the video. This is
true too with AAC coded sound, while MP2 seems to be fine.

To reproduce this I take a MPEG sample containing a MPEG2 video stream and
an AC3 audio stream and do:

ffmpeg -i sample_w_ac3.mpg -vcodec copy -acodec copy out.avi

While playing this file with mplayer, the sound starts in time with the
video, but drifts away quickly.

Interesting, if I do:

ffmpeg -i sample_w_ac3.mpg -vcodec copy -acodec mp2 out.avi

audio and video *are* in sync.

ffmpeg is latest CVS compiled and linked with libfaac, libfaad and liba52.

What output format should I use to encode h264 video and ac3/aac audio with
video and audio in sync?

Anyone able to fix the remuxer of avi out?

Thanks,    Thomas

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