Originally Posted by howzz1854
hey guys, i am at a loss here. i tried calibrating my HDR TV Samsung KU6300 that's connected to my Gaming machine running Windows 10 using the latest HCFR but discovered that there's a huge gamma discrepancy with Windows 10's native HDR WCG mode, vs the MadVR HDR passthrough method. the HCFR HDR10 output seem to be similar to the MadVR, in which when Meta is sent to the tv, all the desktop icons and wallpaper increases in contrast dramatically. but when i use the Windows 10's native HDR WCG toggle, the desktop elements becomes very dull. i know the TV is receiving HDR signal in both cases, but there's just a huge difference in terms of gamma curve and color mapping.
long story short, i tried to calibrate for both output method to see which one will yield the best result and found that when sending the HDR meta through MadVR/HCFR HDR10 it yields the best final calibrated result, while the Windows 10 native HDR toggle after calibrating it with HCFR (without the HCFR's internal HDR10 signal output), I can't get close to the HDR gamma/luminance reference curve and on top of that the color saturation mapping doesn't expand as far out as the MadVR/HCFR HDR10 output method. with the MadVR/HCFR, i can get very very close to the SMPTE 2084 curve, which resembles a snake shape, and the saturation coverage goes out a lot farther on the Rec2020 spectrum. but with the Windows 10 HDR output, the closest i can get the gamma curve is more inline with the regular BT 1886 reference curve, almost looks like a 2.1/2.2 gamma. needless to say, this provides less punch when watching a HDR movie or an HDR game.
when investigating more by looking at the MPC-HE/MadVR info toggle switch (Ctrl + J), i noticed that when using MadVR method, the info shows that the HDR method is "NV HDR". but when doing the Windows 10 method, it shows "OS HDR". all the other info are identical.
i would have just stick with the MadVR method except there're a lot of HDR games out there on PC, some uses the native OS HDR toggle method, while others send meta data when the game boots and triggers the HDR mode method. as you can imagine, this makes the former game look more dull.
can someone explain to me what's going on here.
Windows 10 Home 64bit version 1803
Video card: Geforce 980Ti
CPU Ryzen 2 2700X
TV Samsung KU6300
NVidia control panel setting output is set to Default. but tried YcBCR 4:2:2 10 bit limited but the same result.
Not all things in Windows 10 are made for HDR of any sort. When you turn it on, if there is no HDR10 signal, it pushes the SDR content within a lower set. On Windows 10 1803, they added a slider in the HDR and WCG menu for Brightness for SDR content. This is to try to adjust the nit level for the SDR content, that way to provide better mapping and try to avoid issues related to washed out or dull looking images and icons, which happens when you turn it on with windows controller. HCFR applies the HDR signal in 8-bit, IIRC, but the signal is applied to everything, so those SDR images get put within the stretched HDR/WCG color space. So, there is an extra step when playing with the OS toggle where you should have HDR on in OS, then put up a 100% IRE white/gray pattern being sent in SDR, then adjust the brightness slider in the HDR menu so that you reach your target luminance for SDR content (usually 80-120 nit, I usually go for 120, personally), which then should give slightly better mapping so that you get closer to proper SDR content in HDR on in the OS, while the HDR content, when it is properly sent, should provide correct values. You may need to balance the settings in Nvidia control panel to make sure things are being sent properly to the display. MadVR has the settings for 0-255 and 16-234 as well, so having another pattern to make sure you are sending it properly, whatever means you choose to present that pattern with, would be good to try.
Also, if doing madVR, you may look into reshade, which can allow the use of a 3D LUT with games, although with some tradeoffs. Check it out to see if it is right for you (sorry that sounded like a pharmaceutical commercial, lol).
So, just to be clear, Windows 10's HDR mode allows SDR content to not be stretched into the HDR color space, but without the luminance correction, washes out all SDR content. It is making the effort to try. Most apps are SDR, not HDR. The other two kick it so that it presents the material as HDR, even if not HDR content. I would calibrate with the HCFR or MadVR image (newest version out 9/19), then try to do what I said above for changing the brightness level for SDR. With that, you should have better results and less washout. I have not fully worked out the kinks with OS HDR because it isn't as good as just allowing the graphics card to pass it along. But try that and you may get better results.