Optoma UHZ65LV image drop in brightness during HDR movies

[wall pro]

I installed this projector in my parents' basement for movie nights and it keeps reverting brightness when playing HDR content from my AppleTV 4K. Non-HDR content looks fine. Is there a setting that overrides this auto adjust so Cinema mode stays locked?

 

[chattert0n]

I had the same issue and turning down BrilliantColor on the projector helped a lot with the dim HDR. Also, go into your Apple TV settings and turn off “Match Dynamic Range.” That stopped it from flipping modes and messing with brightness.