Previously, neither ATI Radeon R520 series' ATI Avivo nor NVidia Geforce 7 series' PureVideo assisted front-end bitstream/entropy decompression in VC-1 and H.264 - the host CPU performed this work. UVD handles VLC/CAVLC/CABAC, frequency transform, pixel prediction and inloop deblocking, but passes the post processing to the shaders.
Previously, ATI Radeon R520 series' ATI Avivo and NVidia Geforce 7 series' PureVideo did not assist with front-end bitstream/entropy decompression for VC-1 and H.264; the host CPU handled this work. UVD managed VLC/CAVLC/CABAC, frequency transform, pixel prediction, and inloop deblocking but passed post processing to shaders.