Hey Everyone, I'll keep this brief. I had an 720p MKV file which I used MKVTools to change into an mp4. The video was H.264 so I went passthrough, and the original audio was 6 channel AC3. I converted to 5.1 AAC. When I stream from iTunes to my AppleTV the receiver does not change to a digital format, although I do hear surround channels, but it doesn't sound quite like 5.1 (almost like when Dolby Pro Logic II or something). Any ideas? I have DD turned on in the options, and my system absolutely supports it - I have no problems with my Blu-ray player or my Xbox 360. Thanks in advance!