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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 1 year ago

Jason-GitH commented 1 year 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 1 year 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 11 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 11 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 11 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 9 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 9 months ago

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