It seems there’s a bug on the Apple TV side of things with my setup.

Setup: Apple TV 4K (3 gen) w/ HDMI 2.1 cable connected to HDMI 1 port Sonos arc + sub + era 300 x2 connected to eARC port with HDMI 2.1 cable Samsung frame tv with eARC, input plus, pass through, and atmos enabled.

All apps and hardware are updated.

ATV set to change format “off” and atmos “on” When viewing atmos content in TV+, hbo max, and Netflix apps it works flawlessly. Any DD 5.1 is put through as stereo PCM (e.g. interstellar from TV+) All plex is stereo pcm (including AAC DD 5.1 or 7.1 atmos tracks that are not trueHD encoded, also tried going back to the old audio and video engines) All prime is stereo pcm (no atmos titles showing as compatible, tried nope and a couple others)

ATV set to change format “on” and Dolby digital 5.1, atmos “off” All content in TV+, max, Netflix, prime, and plex can now do DD 5.1, but all atmos is off.

I’m not sure if this is a bug (plex and prime apps) or because of the setting not being able to pick between the two and prioritize one. If atmos is unavailable you’d think it would default to DD 5.1 instead of all the way down to stereo PCM, especially with interstellar through the Tv+ app.

I know there is a long standing issue with ATV and trueHD 7.1 compatibility, but having to switch back and forth is getting annoying.

Anyone else having this issue or have a workaround?