Hm, I haven't actually checked if FLAC comes out as multi-channel, since my ATV4 is connected to my downstairs TV that is set up for stereo only. I'll try connecting it to my main system with surround and report back.Can you see there ever being support for video with Flac audio? I have a handful of BDs I have ripped with Flac and they are only being seen as 2.0. I've noticed this is the case with every video app I've tried, so maybe a limitation of the ATV.