Since you are already trying different images could you try my squeeze desktop image and tell me how that works out? I think it performs a tad bit better than maverick myself. I'm only asking this so I can perhaps compare it to maverick and see what's going on there.
http://www.powerdeveloper.org/forums/vi ... php?t=2262
also one thing to keep in mind is the acceleration is only really for up to 720p videos. some higher res vids will play just fine though but not all.
using my squeeze image right now playing some videos and looking at htop most videos use around 30 to 45% cpu and at least one used between 40 and 70% it all depends on how the videos are encoded.
anyway please give it a shot and let me know if it's still a problem on my squeeze image because that image has improvements to the hardware/multimedia support packages that I've been working on for a while now. (mostly PulseAudio config stuff)
Also if it is a free video could you point me at the video file that is causing you trouble?
Senior Software Engineer
Genesi USA, Inc.