When I try to watch a video with a high HD Resolution 1280 x 720 H264 in Ubuntu it isn't played smoothly. Stops and glitches occur. I don't think this is a problem with the CPU or graphics card, because under Windows there are no problems like this. Could it be a driver problem?
Update: For me VLC Player works best. No stops and no glitches. Smplayer also looks good but the performance leaks similarly to the standard Ubuntu video player in my case.