[FFmpeg-user] A/V sync problems with h264/aac video fragment

Tom Evans tevans.uk at googlemail.com
Mon Apr 16 15:52:04 CEST 2012

On Mon, Apr 16, 2012 at 1:03 PM, Konrad Karl <kk_konrad at gmx.at> wrote:
> On Mon, Apr 16, 2012 at 11:48:46AM +0100, Tom Evans wrote:
>> The 520 certainly handles anything I throw at it, bluray, HD broadcast, rips...
> Pls try to play (1080p50, ~140MB)
> At  00:00:09 (white elephant scene) my GeForce 450 GTS is too slow
> to play it (now I now, thanks to Carl Eugen), I have to use mplayer
> -speed 0.7 at this scene to keep A/V in sync.
> In case your card is able to keep up you might try -speed 1.2 or
> similar to get a feeling about the remaining margin.

I'm not at home, in front of the screen, but it seems to play fine
with speed 1. The maximum A-V in this case is a little high, at most

If I lower the speed to 0.8, the max A-V is much more acceptable, 0.078.

If I bump the speed up to 1.2, then it cannot cope, the A-V rises
constantly, is over a second out within 10 seconds, and over 2 seconds
out by the end of the clip. So it doesn't have quite so much overhead
as I thought!

Running with vo xv, I get big de-synchronization with speeds > 0.4,
similar to vdpau at 1.2. If I use multiple threads, I can go up to 0.6
speed without losing synch.



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