Greetings! I have this issue while playing every kind of video with totem. Horizontal lines spanning the whole screen in the 1/3 to 2/3 vertical region. I tried an approach of testing this issue with vlc + the opengl rendering method: same result. But before this post gets filed under "proprietary ATI driver" issues, I would like to notice that this doesn't occur with a mediacenter application called "XBMC". This app is good for long-play movie entertainment, but since this app is very dominant in a way you can't minimize it, or even get it in a windowed state, the issue becomes very prominent when interacting video with the overall desktop experience (playing flicks in totem or any other desktop-integrated video-player). My hardware-specs consist of a ATI 420x4 cpu, and integrated HD 4200 with 128MB DDR2 sideport memory, 4 GB DDR3 with 512MB shared video memory. I have a long way going with the old Windows enviroment, but i'm a novice with linux (but I like it!). Before thrashing this post, I want to point that, since it's possible to render correct video with XBMC, why isn't it possible with the desktop-integrated players, with this kind of hardware specifications? Rendering method with XBMC is "Advanced Shaders (GLSL)". I've put the gstreamer video default output plugin to "X Window System (X11/XShm/Xv) with device "ATI Radeon AVIVO Video". I've put the "wait for vertical refresh" selector in the Catalyst Control Center to "Always On" (aka "Quality") as well, so i've ran out of options. Just want to enjoy a movie or downloaded flv-flick without firing up that XBMC stuff.

Thank you for your time,
Jeffrey