ATI's Avivo mark 2 - a preview

H.264 video

H.264 is the name of a next generation video format. It is just one of the ways that we can get high definition video playback.

High definition content includes DivX HD as well as Windows Media HD - both of those codecs utilise a version of MPEG-4. However, H.264 is perhaps the emerging dominant standard for HD. It is the encoding standard that is being used in Blu Ray and HD-DVD, it is the standard used in Apple's QuickTime HD, and it is the standard being used for HDTV broadcasts in the UK, via Sky. H.264 is often referred to as a subset of MPEG-4.

You can use H.264 in standard or low-definition content, as well as in high definition content - for example, it is the standard used for the iPod Video.


The codec itself is amazingly mathmatically complex. The computational power required to encode and playback H.264 content is pretty huge. This is especially true of high definition content. As an example, Apple restricts downloads of its High Definition QuickTime content, encoded in H.264, to Apple users with dual processor or dual core G5 PowerMacs. Trying to play back H.264 high definition content on even a high-end PC system - such as as 3.6GHz Pentium 4 - will result in dropped frames left, right and centre.

What ATI are doing is accelerating the playback of H.264 high definition content via the processing power in the X1000 video card. By assisting the CPU in the processing cycle, ATI is enabling silky smooth H.264 high definition content. This will be crucial when we start to see Blu Ray and HD-DVD next year - it's no good having these gorgeous new high definition formats if even our awesome rigs can't play back!

To enable this, ATI are releasing a free H.264 software decoder module in association with Cyberlink. This module plugs into Windows Media Center to let you play back content through that application. Because of the immense processing power required by H.264 video decoding, the different X1000 cards are only able to process certain resolutions. The X1300 can handle 480p and 576p content - basically, standard definition. The X1600 can manage 720p, which is the wide standard for high definition, and is what European and American HDTV broadcasts use. X1800 can manage the highest of high-definition, 1080p. ATI stressed to us that this isn't an 'artificial / marketing' limitation - the power is directly proportional to the pixel pipelines in each card.