Comment 19 for bug 993397

Actually, on my machine DISABLING sync to vBlank(in both Nvidia settings and ccsm), not enabling it (which is enabled by default) partially works around the problem (it does not work for full screen), see my post #3

If furthermore, "undericted fullscreen windows" is checked in ccsm then vdpau works perfectly in XBMC but still not work for mplayer and mplayer2. But it has other side effects such as tearing for Desktop cube.

IIRC there is an option in KDE which disables Desktop compositing for fullscreen applications, I think something like that would probably solve the problem if available in Unity.