Re: vdpau issues (Canon HF20)
Where are you getting all those random command line and config file options from? Many of the ones mentioned in this thread make very little sense.
First, when testing don't use the lists of fallback options - it's better to test one thing at a time and possible fallback to something else only confuses matters.
Having "fps=60" in the config file by default, affecting all videos, makes no sense at all. It's rarely useful for any single video either. Specifying "vo=vdpau:deint=2" also activates deinterlacing by default - not a good idea if you also play progressive videos (maybe it'd be worth changing MPlayer to add syntax to specify the default deinterlace mode without activating it).
The sdl audio output is little used or tested, so it may have problems. Where did you get that from too?
If your content uses PAFF (at least some other avchd samples I've seen do) then you should try compiling MPlayer from the git repo (easiest done using 'git clone git://repo.or.cz/mplayer-build.git', then follow the README). The current git version has better timing code that should handle PAFF videos correctly if you use -demuxer lavf, and it also has an improved VDPAU driver. I think your 9600 GT should be able to handle deinterlacing modes higher than 2; with the git VDPAU driver I can use deint=4 without problems on my 9500 GT.