Thread: mplayer vdpau
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Old 09-25-09, 06:05 PM   #1193
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Join Date: Sep 2009
Posts: 45
Default Re: Blu-ray audio desync in 28900+ mplayer SVNs

Originally Posted by cehoyos View Post
How do you notice? Are frames dropped? Does -framedrop help? -fps 24?
Did you try -demuxer lavf? -demuxer lavf -nocorrect-pts?
Is complete, uncut output of mplayer (preferably with sane configure line) available?
No need to bother trying those, they won't help. It doesn't depend on MPlayer configuration either. The problem is that VDPAU insists on showing every frame for at least one monitor refresh cycle, even if timing would require them to be shown faster (correct playback would mean that some frames never actually appear on the monitor). This means that the video will fall behind if AV sync would require it to be played back faster than monitor refresh rate.

I'll have code to work around this problem by manually dropping frames ready soon, though it'd still be nice if the VDPAU implementation made it easier. Correctly deciding which frames to drop requires knowledge about the timing of future frames, and since VDPAU doesn't allow dropping already queued frames you need to buffer them to have future timing available before sending one to the VDPAU output queue. Calculating the timing also requires you to know the current monitor refresh rate. If the VDPAU implementation can't handle the framedropping correctly itself it could at least directly export the current refresh rate of the display it's syncing to to make it easier to calculate things on the client side.
A range of 100 revisions is not very helpful if you claim a regression (and since this is probably libavcodec-related, you will have to also provide its version - or a date).
I doubt there has been any change in this behavior. And it is not libavcodec-related in any way.

PS: Are you sure this is VDPAU related?
Such video update rate limitations do depend on the video output method used, though VDPAU is not the only one which suffers from this.
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