battling judder with Xv video playback

Vladimir Dergachev volodya at
Mon Dec 20 14:24:42 PST 2004

On Mon, 20 Dec 2004, Torgeir Veimo wrote:

> I'm battling with judder in my setup with vdr & Xv output with streams
> decoded using libavcodec, and I'd like to try to find the real cause for
> this (am suspecting libavcodec).
> Therefore it would be of tremendous help if I was able to instrument the
> X server in some way to log the timestamp every time a new frame is send
> using Xv, and the timestamp the frame is actually blitted to the hw
> scaler. In this way I can find if the problem is in the X server /
> scheduler, or if it's a more fundamental problem with the decoding
> process itself.
> Does anyone have any idea of the best way to approach this? I'm not too
> familiar with X server internals and what would be the best way to
> implement a log mechanism that wouldn't affect the overall playback
> process itself.

Which card do you have ? It might be simple to add timestamping to X 

You can use xf86DrvMsg(0, X_INFO, "slfkjsldjf"); to print messages


                       Vladimir Dergachev

> -- 
> Torgeir Veimo <torgeir at>
> _______________________________________________
> xorg mailing list
> xorg at

More information about the xorg mailing list