[MPlayer-dev-eng] flv A/V sync broken

Uoti Urpala uoti.urpala at pp1.inet.fi
Tue Feb 20 03:18:35 CET 2007

On Tue, 2007-02-20 at 02:41 +0100, Michael Niedermayer wrote:
> > I tested that sample and saw desync when playing without -correct-pts.
> > It seems to work with -correct-pts. I haven't verified the exact cause
> > but flv uses a libavformat demuxer and those generally do not work well
> > without -correct-pts because of timestamp ordering.
> flv1 doesnt support b frames so there should be no out of order timestamps

I checked what was causing it. Seems that demux_lavf sets a fps value
but it doesn't match the timestamps. It sets sh_video->fps to 29.9700298
which makes video.c use a constant 1/fps frame duration, but average
distance between frame timestamps is longer.

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