I'm running Ubuntu Karmic, with Compiz 0.8.4, Nvidia 195.36.15, and X 1.6.4. I have an Atom + ION board.
If I have Composite enabled in xorg.conf I get tearing in full screen videos using vdpau. It's a constant band, about 5% of the way down the screen. I have tried numerous permutations of GL VBlank, XV VBlank, redirect full screen videos, detect refresh rate and VBlank in Compiz, all to no avail.
I understand the appropriate settings should be:
GL sync to VBLank in Nvidia ticked
XV sync to VBlank in Nvidia ticked
Unredirect full screen video in compiz ticked
detect refresh rate in compiz unticked
refresh rate set to TV rate (60Hz in my case)
Sync to VBlank in compiz ticked
The only way I have of viewing videos using VDPAU is to disable composite.
With composite enabled, the nvidia driver must put its video to the blit adaptor, which I believe is meant to be synced by compiz. So I believe this is a compiz bug - or do I need a newer version, a patch, or something?