I have been having this issue a while, and I have not been able to describe it adequate enough so, I filmed a video with my camera and below are the screencaptures from it. The lines appear in all my videos, by vlc, flash, mplayer so its not app related I think. Makes watching action film with fast camera movement on a big screen rather distracting. I hope this helps get me a fix.

http://i217.photobucket.com/albums/c...reenshot-2.png

http://i217.photobucket.com/albums/c...reenshot-3.png

http://i217.photobucket.com/albums/c...reenshot-5.png

http://i217.photobucket.com/albums/c...Screenshot.png

My system
Hardy Heron (8.04 LTS) with 2.6.24-17-generic (gnome)
nvidia 7300gt card, using compiz
screen is 1024x768 50hz