y the h264 branch is just slowning down the whole machine. the video plays in a slideshow
unfortunately, that's the status - Intel are lying to us (G4x owners) for several years that they will provide Linux driver with H.264 acceleration then they submitted some initial code for that on May 16, 2011 and afterwards no any further updates or as of now H.264 acceleration with Intel G4x in Linux is not existing in practice.
however, it's interesting that according to Intel there are no such problems and it should work:
Seems to work for me as well. Using a 1080p bluray rip (10GB) CPU usage on mplayer went from around 30% to 3%. But it doesn't work with multithreading yet. Setting threads to anything other than 1 and the CPU goes back up to 30%. To get high bit-rate files, like the one above, to work, I didn't setting SwapbuffersWait to off in my xorg.conf, since I don't have one. Instead, I just gave mplayer an unusually high cache (27MB), and that seemed to fix frame drop issues.