View Single Post
Old 12-08-08, 07:11 AM   #14
Registered User
Join Date: Aug 2007
Location: Austin, TX
Posts: 120
Default Re: 1920x1200 video playback performance

Originally Posted by azenz View Post
Hi guys, thanks for all the advice, I tried the refresh rate settings in compiz and no improvement. I do feel from the looks of it that this is some kind of performance issue and not a refresh rate issue, because the problem comes mostly in high motion scenes with lots of panning and movement (and not all the time). I am just not sure where the performance bottleneck is considering that my system has good specs.
That's precisely the behaviour you would expect if vsync was not working correctly. The tearing occurs because part of a previous frame is still being displayed while the next one is being written. In high motion scenes the tear is more obvious because the spatial disparity is larger.

A "performance" issue would manifest itself as a low frame rate, or dropped frames, neither of which is likely on a modern GPU that is just rendering (and not decoding) a video. The fix for me was to disable Sync to VBlank under "X Server XVideo Settings" in nvidia-settings and enable it in CompizConfig Settings Manager -> General Options -> Display Settings -> Sync to VBlank. Then using e.g. VLC with XVideo output the tearing goes away.
jcornwall is offline   Reply With Quote