That is definitely not working as intended, and we will need more details to figure it out.
Can you file a bug on https://bugzilla.mozilla.org/ in the component "Graphics: Color Management"? In particular I would like to see if certain errors appear...
Ah, yeah setting `layers.acceleration.disabled` to true is a fast path to no HDR features. As we upgrade more of the rendering to support HDR (for still images and other features) we will continue to require hardware acceleration for HDR features. ...
Thanks for the report, I've filed a bug https://bugzilla.mozilla.org/show_bug.cgi?id=2064486, and appreciate the inclusion of the display info from about:support, there are more parts of about:support that would help understand what is going on there...
I assume you mean MPO (multi plane overlay)? Can you describe the repro situation where flickering occurs with the compositor enabled?
We've been tracking various forms of flickering bugs with MPO in https://bugzilla.mozilla.org/show_bug.cgi?id=1638...
Thank you for the screenshots, having them helps a lot in understanding the problem, that screenshot looks like BT2100 PQ (sometimes called HDR10) video being displayed as BT709 (which makes it washed out and dull). If you are up for filing a bug on...