ATI's Avivo Platform - H.264 Decode and Transcode Acceleration on R5xx

GPU Accelerated H.264 Decode

Transcode acceleration isn't the only thing that the R5xx GPUs will be doing; as we saw at Computex, ATI has had working H.264 decode acceleration for months now, and it will be a requirement for all Avivo platforms.

All Avivo graphics cards (e.g. R520, RV530, RV515) will feature decode assist for H.264, MPEG-2, MPEG-4, VC-1 and WMV9. This feature will be enabled on the day that the products ship, through Catalyst.

Keep in mind that we're still talking about GPU assisted decode, so there are still a lot of functions that are done by the CPU. Avivo GPUs will perform in-loop deblocking, motion compensation and inverse transform.

ATI performed the same demo for us that we saw back at Computex (this time on a dual core machine however), and the performance results were very similar. CPU utilization dropped from 90% down to around 30% while playing a 20Mbps H.264 stream.

Based on ATI's chart, it's not too hard to see why the GPU assisted H.264 decode reduces CPU utilization by so much. Note that reverse entropy does appear to eat up quite a bit of CPU time, which the R5xx GPUs do not handle. This is most likely why CPU utilization is still not insignificant even with decode assist enabled.

The H.264 decode acceleration of Avivo GPUs is quite important, mostly because both the next-generation DVD standards (HD-DVD and Blu-ray) will both use H.264 as the encoding format for video stored on the discs.

For what it's worth, NVIDIA has committed to delivering H.264 decode acceleration later this year on their GeForce 7 based products; but we have yet to see a live demo of the technology.