Just a quick note that VDPAU patch was applied to FFmpeg on 5 January 2008. VDPAU enables hardware decoding of MPEG-2 and H.264 streams with Nvidia cards. Testing under Mplayer shows that even heavy 30Mb/s ATSC 1080i streams can be fully hardware decoded. Even cheap Nvidia 40€ video cards support hardware decoding.
There is still development needed in MLT to support VDPAU. Contributors are welcome to join MLT team and implement VDPAU.