I remember setting up mythtv frontend on my acer revo (nvidia ion) and making sure vdpau is selected there.
Hope this helps.
Thanks for the reply.
I did see that option, but myth seems to crash when I use it (only the vdpau ones, there are 3 right?). The other options (CPU++, slim, etc) all work, but give me the motion blur. I can't remember the error message exactly, think it was "Video frame buffer failed too many times", but can't be sure. I'll check it out and report back.
Thanks again for the suggestion.