X-bit labs

Highly Defined: ATI Radeon HD 2000 Architecture Review (page 9)

Category: Video

by Anton Shilov , Yaroslav Lyssenko, Alexey Stepin

[ 05/15/2007 | 07:34 AM ]

Avivo HD: FullHD Gets to PC

Despite of the fact that high-bandwidth copyright protection technology (HDCP) is currently supported by almost all new graphics cards, this, unfortunately, does not mean that end-users can enjoy 1080p movies from Blu-ray and HD DVD discs on their PCs. Apparently, previous-generation graphics chips do not support HDCP for resolutions requiring dual-link DVI connection. Moreover, when previous generation graphics cards used, users were not able to have multi-channel audio, as they had to use mini-jack connectors to connect audio cards to their audio systems, which, due to HDCP, would "downgrade" number of output channels to stereo.

The Radeon HD 2000 has solutions for both issues and bring even more powerful hardware for decoding HD content. The new chips support HDCP for all resolutions and also contain built-in audio controller, which allows to transmit audio using HDMI output of graphics cards (for that ATI equips its cards with DVI->HDMI adapters). As a result, end-users can now enjoy both 1080p movies as well as multi-channel audio with their systems equipped with Radeon HD 2000 graphics cards as well as special optical drives.

The new Radeon HD 2000 graphics chips also feature improved Avivo HD technologiw with unified video decoder processing unit, which supports such functions as decoding of Context-Adaptive Variable Length Coding (CAVLC) and Context-Adaptive Binary Arithmetic Coding (CABAC) entropic encoding algorithms of H.264 and VC-1 codecs.

It is interesting to note that ATI claims support for full hadrware decoding for both H.264 and VC-1 codecs, whereas Nvidia only claims support of bitstream processing for H.264 and not VC-1. Unfortunately, current ATI Catalyst driver does not support acceleration of VC-1 decoding at all, hence, we cannot compare Avivo HD and PureVideo HD just now.

Radeon HD 2900 XT with HDMI adapter. Click to enlarge

Full hardware decoding of HD content is tremendously important for mobile computers, as while contemporary processors can process even 1080p movies, mobile chips would consume much more energy than a GPU with dedicated hardware: according to ATI, system power draw of HD DVD playback without GPU-assisted decoding is about 52W, whereas with GPU-assistance it is about 35W. Given that notebooks with Blu-ray or HD DVD optical drives are becoming more and more popular, AMD may win several designs with its Radeon HD 2000 products thanks to their advanced video capabilities.

It is also interesting to note that Radeon HD 2400 and Radeon HD 2600 have special custom logic for video post processing which improves quality of deinterlacing with edge enhancement, vertical & horizontal scaling as well as color correction.