That was it! Thanks @Mark McSherry ! Why do they make this stuff so difficult? When I got the receiver I didn't have 4K, so I left that where it was. I went through every single menu in the ATV and UHD player ten times, but never even occurred to me to go into the receiver's.
So, I have the ATV 4K's "Format" set to 4K SDR. What I didn't understand before I had HDR is that "Format" on the ATV 4K just sets the video format of the menus. I want a minimum of having to wait for the TV to switch around between formats all the time, so I set it to 4K SDR with Range and Frame Rate enabled in "Match Content". Then it changes to whatever HDR and frame rate of the actual movie or show, once you start playing it. My TV has a 120Hz refresh rate, so it's outputting Jessica Jones, for example, at 4K 24Hz Dolby Vision. All is right with the world.
BTW, the SR7012 was on the ATV input when I enabled the 4K Enhanced mode, and the ATV automatically sensed it and activated 4K Dolby Vision. Then I went ahead and deactivated it.
So, I have the ATV 4K's "Format" set to 4K SDR. What I didn't understand before I had HDR is that "Format" on the ATV 4K just sets the video format of the menus. I want a minimum of having to wait for the TV to switch around between formats all the time, so I set it to 4K SDR with Range and Frame Rate enabled in "Match Content". Then it changes to whatever HDR and frame rate of the actual movie or show, once you start playing it. My TV has a 120Hz refresh rate, so it's outputting Jessica Jones, for example, at 4K 24Hz Dolby Vision. All is right with the world.
BTW, the SR7012 was on the ATV input when I enabled the 4K Enhanced mode, and the ATV automatically sensed it and activated 4K Dolby Vision. Then I went ahead and deactivated it.
