Quote:
Originally Posted by huhn
the brightness level of the none compressed parts match at gamma 2.2.
so if you want the correct brightness levels you set this screen is already calibrated to your screens response where unlike SDR madVR will automatic change your "gamma" for HDR sources to 2.2.
as i said before i'm not a friend of this inconsistent behaviour between HDR and SDR.
|
I know one user was getting what looked like correct HDR gamma tracking at 2.20 with madVR set to clipping. But I sent that person a black clipping pattern and they were clipping some black. So I'm not sure if 2.20 is "correctly" following the PQ curve in all circumstances.
None of the SDR gamma curves have equal response to the original PQ curve:
Image: Gamma 2.20 vs. PQ ST.2084
I would assume madVR would have to tell the display to flash the correct amount of voltage to get a PQ value from an SDR gamma curve and use all kinds of dithering to fill in all of the extra shades of gray required at the low end of the curve.
When tone mapping, changing the target nits also radically changes the perceived gamma, so there is more to the gamma response than just choosing 2.20 or 2.40. It is more customizable than that. As long as you can see reference black, you can make the image darker or brighter as required to get a smooth transition from dark to light. The original tone curve will be compressed either way.
I think there are some who seem to be getting an accurate image with both 2.20 and 2.40. And there are some that I know of that get some black crush when madVR is set to 2.20. You have to test black clipping or you may notice any crush.