Exactly, that is my point, default MC-install doesn't seem to do any tonemapping with its default settings? But maybe the "led madVR decide" isn't the best setting here?
I don't use "let MadVR decide" for HDR simply because I have no idea how MadVR decides … in your case it seems MadVR chose to passthrough HDR metadata (ie it chose not to do tone mapping and let TV do it … this only works in Full Screen … your TV should enter HDR mode … this would explain why your screenshot of MC looks wash out - it was not running full screen)
madVR 0.92.16 shipped with MC has following option for HDR
1. [let MadVR decide] … I don't use this as I have no idea how MadVR chooses between 5 available choices
2. [passthrough HDR content to the display] - MadVR don't do tone mapping and let TV do it (obviously TV must support HDR) … box [send HDR metadata to the display] must be ticked otherwise TV would not know if it suppose to do tone mapping … this only works if video is played in full screen mode … your TV will enter HDR mode (if it does not - something is not working correctly)
remaining 4 options are [convert HDR content to SDR] and [process HDR content] with options to do it with "pixel shader" or "3DLUT"
3DLUT is not something average person can do … so most ppl will use pixel shaders … this uses GPU … so might need to tone down on scaling algorithms to avoid frame drops
the deference between [convert] and [process] … is later allows you to send HDR metadata to TV for TV to do further tone mapping (though purpose of this escapes my limited understanding of HDR)
In summary … if you want TV to do tone mapping … choose [passthrough HDR content to the display] with [send HDR metadata to the display] box ticked
If your TV is not HDR or its tone mapping suck bad … choose [convert HDR content to SDR by using pixel shader math] … most important setting there is target nits
… google your TV to see its max nits … you don't want to set target nits higher than what your TV can do or there will be clipping
PS. be aware when comparing passthrough with convert to SDR … when TV enters HDR mode in passthrough it uses separate settings for brightness/contrast (usually much brighter) … so you need to adjust your TV brightness in normal mode to match your target nits in conversion, which might make your regular SDR content not so good