Nvidia has patches and a build script to automate everything. Grab it:
Extract it and navigate to the resulting directory. Run the checkout-patch-build.sh script -i ran this script and it did a bunch of unloading and patching, then on the last 2 things it tried to do, it says something error1 and error2
. It will download the latest svn mplayer, apply the patches, and compile mplayer. When it's done you'll have, amongst other things, an mplayer executable in the mplayer-vdpau directory - did not see any mplayer executable in the folder.