Originally Posted by Javs
SDR BT2020 is tone mapping. That's also what the Panasonic if and Oppo does. Along with Lumagen I believe.
When you use madvr tone mapping it actually needs your display to be in gamma 2.2 mode.
Originally Posted by mavromatis
So if you use madvr tone mapping we need to use gamma 2.2 instead of 2.4?
Originally Posted by Javs
You have to tell madvr which gamma you are using. But the tone mapping algorithms are based on a 2.2 working space so it's best to use that.
You could set it to 2.4 in the on the pj and madvr but it will probably not look different.
Originally Posted by grendelrt
I thought that gamma 2.2 was only if you were using a 3d lut and not pixel shaders?
Just to clarify, madVR pixel shader tonemapping *doesn’t* need the display to be set to a 2.2 gamma.
The display can be set to anything. If what you set it to is accurately calibrated to what you tell madVR it is in the calibration tab ("this display is already calibrate to"), it shoudn’t make any difference. If you use a 3D LUT, the LUT *target* has to be 2.2 but the display itself can still be set to anything.
Let me explain.
If you don’t use a 3D LUT, set your display to any gamma you like. For example, if you need it to be set to 2.4 so that your SDR WCG calibration is also compatible with the output of a player (Oppo, Pana) outputting 2.4, then it’s absolutely fine to tell madVR that your display is already calibrated and tell it to which gamma/gamut.
It will convert to PQ though, which is absolute, so whether you set your display to 2.0, 2.2, 2.4 or 2.6, the result, provided the display actually tracks what you are telling madVR, should be exactly the same.
If you select (and calibrate the display) to 2.2, it won’t look like 2.2, it will look like PQ.
If you select (and calibrate the display) to 2.4, it won’t look like 2.4, it will look like PQ.
This is because madVR’s pixel shader tonemapping converts to PQ gamma.
Now of course if you lie to madVR and tell it a display tracks a gamma it doesn’t, the results will be different, but they will also be inaccurate.
So simply tell madVR what the gamma closest to the actual gamma tracked by the display is, so that madVR’s output is closest to PQ.
If you do use a 3D LUT, you can also set the display to whatever you like, and it doesn’t have to be accurate as any inaccuracy will be delt with by the LUT.
But you *have* to give the LUT a target of 2.2, because that’s what madVR expects internally. This won’t look like 2.2 in a dedicated room (washed out vs 2.4 or higher) because the madVR’s output will, again, be PQ.
I’ve explained this in the JVC calibration thread for 2019 models in a short note to madVR users in my recommended settings a few days ago, and I’ll post there recommended settings for madVR playback and calibration after a public build is released, as at the moment the settings for tonemapping are changing daily. Make sure you follow the 2019 calibration thread if you want any updates.