Apparently, from what I understand, Nvidia's CUDA is the best. VDPAU and DXVA are similar.
Neither work as well as CUDA on my machine.
As I mentioned earlier, CoreAVC uses both cores of the CPU very well so if you disable CUDA,
it uses as much CPU as it can get/needs (95% on my box).
On the other hand Smplayer in pclos only uses 50% of the CPU, (no chance of playing this file like that)
hence my original point about multi-threaded player.
ON my (relatively) old 8600GT, HW acceleration is not as advanced as some of the new cards.
For example, 720p H.264 files will play fine with HW acceleration in VDPAU and DXVA but 1080p will not - but 1080p
plays great with CUDA.