I've been testing HD-DVD playback with Xbox 360's HD-DVD drive and latest version of Cyberlink's PowerDVD which includes support to Radeon X2000 series hardware decoding (http://www.cyberlink.com/multi/downl...7_112_ENU.html)
I have two HD-DVD movies here, Serenity with VC-1 codec and Wolf Creek with MPEG-4 AVC (H.264) codec. With both movies there are absolutely no benefit from Radeon HD 2900 XT's hardware acceleration feature in PowerDVD settings. For example with Core 2 Duo E4300 average CPU load remains at 72 % with H.264 movie (GeForce 8600 GTS 14 %).
Yesterday AMD's Dave Baumann posted this to B3D Forums which explains why:
"HD 2900 does not have UVD; it'll be paried with HD video capable CPU's."
The weird thing is that the biggest hardware sites in the world are writing in their Radeon HD 2900 XT articles that R600 supports UVD:
"The R600 Video Decode Pipeline: UVD"
"AMD is one upping NVIDIA this time around, as their UVD (Unified Video Decode) architecture is also capable of decoding VLC bitstreams on all three HD media codecs."
(Although they tested the feature..)
"Either way, the best way to figure out what's going on is to take a look at performance and see if there really is any advantage to R600 over G86. Unfortunately, try as we might, we could not get UVD to work with the current drivers provided by AMD and the PowerDVD release that is supposed to enable the hardware acceleration on HD 2000 series parts. We will have to take a second look at hardware decode when AMD and CyberLink or Intervideo get their software in order."
"This new processor is called a UVD for Unified Video Decoder. While it is a processor unto itself, the silicon is actually a part of R600, much like how the 2D and 3D engines are internalized."
Tom's Hardware: http://www.tomshardware.com/2007/05/...ti/page16.html
"All '6-family products and the GPUs that drive them contain a new video decoder block, which AMD worked with Tensilica to build, called UVD, or Unified Video Decoder"
"Every SKU of this new generation of Radeon could perform (almost) full CPU offload acceleration for video playback for all three current optical disc formats."
"All of the new members of the Radeon HD 2000 family of GPUs feature a new AVIVO HD video engine with better performance and more functionality than the version found in the Radeon X1K family of products."
"The new AVIVO HD engine features AMD's Universal Video Decoder technology, which basically offloads every major aspect of HD video processing from the host CPU and performs the functions on the GPU."
"In addition to all of the new graphics goodness, the R600 brings with it some important new capabilities for high-definition displays and video playback. The most prominent among them is a brand-new video processor AMD has dubbed the UVD, for universal video decoder. The UVD is a dedicated processor with its own instruction and data caches, and it can accelerate key stages of the decompression and playback of HD video formats for both HD-DVD and Blu-ray, including H.264 and VC-1."
The Tech Report: http://www.techreport.com/reviews/20...t/index.x?pg=9
Some sites like Hexus and HardOCP are writing it correct: R600 doesn't include UVD.