[Gordio]

Is it not? I posted this a while ago,and most people say HD content is way too huge. However, what about streaming? I think most people would say "hell no!" but I always wondered how my comcast HD can stream so much. DSL is only half the speed.

Doesn't this mean it's technically possible for HD content to be on apple tv (streaming)?

[mduell]

The Apple TV has limited support for HD (720p only, with some other restrictions). If you have some HD content on your computer you can stream (or cache) it to the Apple TV.
Comcast is sending their HD programming over cable broadcast, not over a cable modem. Current high-end broadband connections (30Mbps FIOS) are fast enough to stream good quality HD content, but few people have them and it takes a crapload of bandwidth for the server with multiple clients.

[GORDYmac]

Video formats supported: H.264 and protected H.264 (from iTunes Store): 640 by 480, 30 fps, LC version of Baseline Profile; 320 by 240, 30 fps, Baseline profile up to Level 1.3; 1280 by 720, 24 fps, Progressive Main Profile. MPEG-4: 640 by 480, 30 fps, Simple Profile