HandBrake

QuickTime Player 7.1.3 will open mp4 files with 6-channel AAC files, but there's a bug on Intel which causes QuickTime Player to crash when you do. It works fine on PPC, or on Intel if you open QuickTime Player under Rosetta. Yes, I managed to get AAC 5.1 audio in an mpeg4 file a while ago while us...

If you have .srt subtitle files for the movie (easy to find for most movies if you google 'DivX subtitles'), you can convert them to QuickTime text with TitleLab and add them to the movie in QuickTime Pro. You can then save as a self-contained movie (.mov) to have the tracks embedded or as a referen...

I'm affraid there's a very slim chance it will work with the AppleTV, since it seems to be very limited in the formats it understands, avi files don't seem to be one of them. It's even very doubtful that it will play mpeg4 files with aac 5.1 audio, since QuickTime only seems to support that in a .mo...

You can also use the free program QT Sync to change the aspect ratio and save as a .mov file (for those who don't want to pay the extra cash for QuickTime Pro).