I'm considering buying an atv and would like to know what restrictions there are for playing mp4s on the atv. I'm aware of the appletv specs page and have looked on there and I find it hard to believe that the appletv can't play 1080p and that the bit rate is limited to 4000? Can anyone confirm this? I'm assuming people use their atv's for HD playback so does this mean that you can only do 720p? and the 4000 bitrate isn't really enough for that?! Also, is there a file size limit?