I have noticed with the latest tvOS updates as of October 2022 that I can set my AppleTV to 4K SDR and when I go to YouTube and play HDR videos it will switch on its own. then if I go to Apple photos and play videos that are Dolby Vision recorded on my iPhone they will switch. That’s a new thing! we used to have to manually set our AppleTV into HDR or Dolby Vision mode to make that happen. so that’s cool. I noticed though that despite this working some of my iPhone recorded Dolby Vision videos simply won’t play in Dolby Vision. they continue to play as SDR. not sure why. Progress, though.
