site, you may have been disappointed not in the quality of the video, but the playback experience. Apple uses the H.264 codec for all of its HiDef video, as it makes sharp pictures with smooth motion while maintaining reasonable file sizes and throughputs. The problem is, the heavy compression needed to get the quality you see takes an enormous amount of processing power to decompress. That’s why even on a fairly new computer you might see stuttering with the 720p version of a trailer, and wouldn’t even want to try the 1080p.
That’s all software, though. Hardware decompression is much more efficient and takes the heavy lifting from the processor and “out sources” it to a dedicated chip. The idea’s not new: Apple shipped certain models of its G3 series Powerbooks with hardware MPEG decoders for the built-in DVD drives, and according to Cringley, its set to do the same thing with forthcoming Macs and H.264.
This would explain how the Apple TV, with its relatively meager specs, will be expected to smoothly output 720p or even 1080p video in H.264 without choking. Adding the same tech to Macs would be a logical piece of cake.
The Great Apple Video Encoder Attack of 2007 [I, Cringely]