The iTunes download service from Apple has a growing list of movies available to purchase or rent. However you can only purchase either an SD version of the movie or pay extra for a so-called "HD" version. That HD version, however, only goes up to 720p resolution. So far Apple has yet to offer its customers access to full 1080p (1920x1080) high resolution video downloads. But according to the latest rumor, that might be changing in the near future.
According to AppleInsider, it has learned via unnamed sources that that the service could start offering 1080p movies in September or October. The sources claim that upcoming movies will soon be available for purchase via iTunes in SD, 720p HD and the new 1080p resolution. Those movies will have a bitrate encoding of 10,000 kbps on average, according to the story.
The same story states that Apple might be getting ready to release a new version of the Apple TV device which can store videos from iTunes and play them on a big screen TV. The story claims that the Apple TV revision will have the dual core A5 chip inside which is the same chip in Apple's iPad 2. That chip is capable of handling the 1080p video. However, the story speculates that if Apple were to offer 1080p video via download it would do so as a direct download just for the PC and Mac platforms. 1080p files would certainly be much larger in terms of file size compared to the current SD and 720p HD movies that Apple currently has on iTunes.