For those still using Vista, or maybe those who just don't like the media foundation codecs, the latest releases of ffdshow-tryouts now contain support for DXVA decoding of HD material.
I know it's in the branch build by albain, or alternatively you can use Shark007's codec pack which includes the latest DXVA version.
I should note that with DXVA you lose all the great things about ffdshow like post-processing, sharpening, debanding and resizing.
