Min Luminance for OLEDs

[hk1249]

I am using a calibrated C2 (w/ spectro and colorimeter). Using the VESA DisplayHDR Test app from the Microsoft Store to check MaxCLL, MaxFALL, and MinCLL using your profile, min luminance is not set to 0 like with the profile generated by the HDR Calibration App with an OLED (C2). Is this cause of the corrections needed for the profile from sRGB to 2.2? Or is it just not possible to completely correct the issue. Thanks for the work btw.

Using the HDR Calibration App profile with settings for a LG C2 (800,800,0)

When using the HDR Calibration App to just check the min luminance and using 0.0050, you can still see the grey window outline in both situations with and without the profile active.

[dylanraga]

I noticed this, but not sure what tag makes the Windows HDR calibration ICM report zero nits. Though from what I've seen, nothing really seems to use this min luminance value, and metadata-aware media players show no difference in tone mapping swapping between my profiles and the Windows HDR calibration profiles.

[hk1249]

Sounds good. Little off topic but do you happen to know why the 42" LG C2 clips at 800 nits using the HDR Calibration App? The 42" C2s don't come close to 800 nits. I've seen 650-700 depending on whitepoint even with a smaller window size. After calibration my C2 hits 650 nits on 10% window w/ D65 whitepoint and HGIG. I've also tried using tone mapping off and uploading a new tone curve with my peak and 100% values, still clips at 800 nits on the app. It's prob not a big issue since there's a lot of games that just use their own HDR calibration anyway. Just something I've been trying to test using EndlesslyFlowering's reshade HDR analysis tool I'm wondering if editing the EDID with CRU is the better way to go with your untagged profiles.

[dylanraga]

@hk1249 I've investigated and tested this every now and then. Came to the conclusion that LG simply bakes in this tone mapping in its 42-inch TVs as an additional LUT step to "match" it with the larger sizes (48"+) that do get up to 800 nits. This tonemapping is there even with HGIG enable or DTM off. This way, LGE does not need to create two separate HDR10 master LUTS for the C2 series. Just one, and an additional roll-off specifically for the 42-inch.

[hk442]

Thanks for the response. Appreciate you still keeping track with this. So yeah using that reshade HDR tool you can analyze the peak nits and for games that go over your display's peak and you can cap it using the static tonemapping tool. I've been capping the nits at my display's peak of 660 nits instead of using 800. Some games even go over their set peak from the settings so it's very useful. It also has a tool to fix raised black level in games however if you use your profile I don't think the tool recognizes the profile's corrected black level. Probably comes before the pipeline or the tool needs to be configured to recognize it. But the profile is much easier and a "set and forget" while the black level tool requires a bit of tinkering using the analysis tool. Good to have options though.