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dylanraga / win11hdr-srgb-to-gamma2.2-icm

Transform Windows 11's virtual SDR-in-HDR curve from piecewise sRGB to Gamma 2.2
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Should we be using this for Auto HDR games as well? #19

Open Jason-GitH opened 9 months ago

Jason-GitH commented 9 months ago

Does Windows correct gamma to 2.2 for SDR content in Auto HDR? Or do we need to use these ICC profiles for Auto HDR games?

dylanraga commented 9 months ago

AutoHDR games are interpreted as sRGB, extending only their midtones and highlights. Thus you should use the gamma correction to improve the contrast of AutoHDR games.

Filoppi commented 6 months ago

What @dylanraga said above is correct, though I don't think AutoHDR follows the same paper white nits values that the SDR->HDR content brightness sliders has: image so it's going to be a lot harder to find the proper icc profile between the ones available in this repo.

I suggest using SK or DXVK AutoHDR as an alternative.

Filoppi commented 6 months ago

Yes, I tested this. AutoHDR with a SDR brightness slider value of 0 roughly matches raw SDR->HDR upgrades done with a slider value of 43 (~250 nits). Thus if using one of these 2.2/sRGB gamma mismatch profiles, you should use one that targets 250 nits if you want to correct gamma mismatches while playing AutoHDR games (at brightness 0).

Proof screenshots: AutoHDR comparison.zip

dylanraga commented 6 months ago

@Filoppi makes a great point, and it's something I've noticed. You would expect an Auto-HDR intensity of zero to be identical to SDR, but it's not. Even with the intensity set to zero, there is does some extra global lifting.I believe it's either game- or APL-dependent. Running some test patterns within World of Warcraft's UI colorpicker, with the Auto-HDR intensity slider set to zero, paper white measured at about 160 nits (up from 100 nits/slider 5). When using a 100-nit 2.4-gamma transformation, I measured an in-game base gamma of ~2.26.

BanTheRobot commented 5 months ago

Yes, I tested this. AutoHDR with a SDR brightness slider value of 0 roughly matches raw SDR->HDR upgrades done with a slider value of 43 (~250 nits). Thus if using one of these 2.2/sRGB gamma mismatch profiles, you should use one that targets 250 nits if you want to correct gamma mismatches while playing AutoHDR games (at brightness 0).

Proof screenshots: AutoHDR comparison.zip

Hello, thanks for the info. How would you handle this if you set the Game Bar HDR intensity to a higher value? Currently I use HDR Calibration (0,800,800) + HGIG + 40% SDR-HDR slider and Game Bar HDR intensity set to 90%. Based on HDR + WCG Image Viewer it estimates the nits to be 797. Would I make a custom profile for 800 nits just for in-game auto HDR only?

Citrus333 commented 4 months ago

So basically, to avoid overcomplicating things. Turn off AutoHDR always and just use these ICC profiles to make SDR look like HDR.