Since installing 1.1 and Kubuntu 7.04, I've noticed that I'm having difficulty getting smooth video playback. It doesn't matter what type of content I try to play. SD and HD material display the same symptom. There's a lot of tearing in the image and playback is jumpy. The problem exists using both xv and xvmc/xxmc, but the problem is worse when using xvmc. I did some investigation and isolated the problem to the Composite extension in the xorg.conf file.
Option "Composite" "Disable"
If I set Composite to "Disable" the playback is smooth. It appears to be an nVidia driver issue with either KDE or Ubuntu 7.04, but I'm not sure which. People are having tons of issues with the current nVidia drivers and Ubuntu over at the nvNews forums. The most recent nVidia drivers have exhibit this problem on my box. I've tried 9755, the latest legacy driver, and the 100.xx nVidia beta driver. The catch is that disabling Composite prevents me from using UI2 with alpha-blending. I can still run UI2 with Masking however, so all is not lost.
I wanted to point this out in case others are seeing playback issues with nVidia cards. Here are my system specs.
2GB dual channel RAM
nVidia 9755 driver (same issue with beta 100.xx beta driver)
Avermedia A180 ATSC\QAM card
Olevia 532H HDTV connected via DVI