I'm getting issues with Xv on a GeForce MX4000 (NV18) card; when I play HD video on mplayer using 'xv:adaptor=0' (the default adaptor), the video does what is in the summary. If I use 'xv:adaptor=1', the video plays fine. This doesn't happen with SD video.
I put up a sample on this link (first 12 seconds of Code Geass 20; the problem is most noticeable on the scene you see the mecha):
*** This bug has been marked as a duplicate of bug 17462 ***