The ATI 3450 & 3650 cards do assist with hardware decoding & encoding of HD video.
3650 specs inc:
Integrated AMD Xilleon? HDTV encoder
MPEG-2, MPEG-4, DivX, WMV9, VC-1, and H.264/AVC encoding and transcoding
Seamless integration of pixel shaders with video in real time
Two integrated...