I have a Radeon HD video card and I wanted to play mkv files (h264) with my video card's power since my cpu cannot play 1080p. Here's what I did to get it to all work.
Well MPC-HC was able to play mkv files using DXVA and the video card's cpu just fine, if I blocked the external filters ffdshow video decoder and CoreAVC. I uninstalled CoreAVC anyways. So I thought if MPC-HC could do DXVA, then surely WMP or BSPlayer could also. You need to get the standalone video decoder from MPC-HC and register it.
Download from:
SourceForge.net: MPC - Homecinema: Downloading ...
Copy MPCVideoDec.ax to a folder, such as C:\dxva
Then go to command prompt and type the following: "regsvr32 C:\dxva\MPCVideoDec.ax"
At this point, WMP should use DXVA just fine but BSPlayer will not work correctly.
In BSPlayer, go to Options, Preferences. Go to the Video Rendering tab.
I did this on Windows XP SP3, Vista may be different for all of this.
Set the rendering mode to VMR7 and CHECK "Use YUV mixing mode with VMR Renderer"
Now you still need Haali Media Splitter, and I'd recommend AC3Filter and FFDShow (audio decoder only)
Good luck!