I'll try to keep this brief: I did AC3 Passthru PLUS AAC Stereo using the Handbrake presets for a handful of DVDs I own to test out converting my collection to an iTunes-compatible format. Prior to the 5.1 update, all was working well; 5.1 when playing through the Apple TV, stereo when I played the exact same file on my iPhone or iPad. Now the same files still play fine on my iPad and iPhone, but the Apple TV refuses to output any audio on files that have an option between 5.1 and 2.0 (stereo). I went into Netflix on my Apple TV, picked a movie with 5.1 audio, and it played back properly without an issue. My Apple TV is connected to my receiver via HDMI-only and my receiver is connected to my TV via HDMI as well. I've tried both forcing Dolby Output to "On" and "Auto" as well. I've found some comments on Apple's support forum from several years ago stating that using optical might fix a similar issue, but I fail to see why Apple would take a step backwards in HDMI-connectivity. :/ Since no one else seems to be complaining about this recently anywhere I've seen, it must be me. Does anyone have any suggestions?