Trusted Reviews has a preview of ATI's AVIVO technology:
While the battle for 3D gaming performance is at the heart of the graphics card, ATI hoped to gain extra brownie points by announcing its AVIVO platform. This is a technology that according to ATI was designed to provide the optimal video experience on the PC. The headline feature was hardware support for H.264 but this actually proved to be something of a damp squib as there was no driver support. However, this is set to change as at a press conference a couple of weeks ago, ATI revealed to the press that on December 22nd it will make Catalyst 5.13 available for download, which will finally enable hardware the assisted acceleration of H.264 on the X1000 series.