Ever since I’ve installed Windows 7, it seems as if hardware video acceleration no longer works. In WPF MediaKit, wmv HD files that used 8% CPU in Vista are now running at 35% - 45%. This is a quad core too!
I doubled checked the graph and I confirmed that the wmv DirectShow filter was sending NV12 samples to the renderer! After scouring the internet, I found something that worked for me (not saying it will for you!) and now my wmv files are back where they should be, ~8% again.
Here is what I did:
Download DXVA Checker
Click “Check DirectShow filters…”
Select a WMV HD file when prompted.
Right click on the “WMVideo Decoder DMO” and select “Enable DXVA”
Again, this worked for me on my NVidia, but who knows how it’ll work on your configuration. I do have the latest drivers installed from NVidia, but that never fixed the DXVA issue. Hopefully this will be fixed by the time of Windows 7 GA.