[nsnhd]

Using madVR with a 3DLUT simulates HDR by adding post processing but does not put my display into HDR mode. (similar but in no way the same as @Gereral1 because the post processing is much more intense than bumping color settings). I verify by looking at contrast and backlight. The mode I am looking at is the 2D calibration. No new mode engages. While the picture is not dull and looks decent, this calibration is not ideal for HDR as is @Gereral1 method. I have to manually max out the contrast to get the full benefit. This does not wash out bright scenes/bright objects and looks as it should. You tell me "A) MadVR autoswitches the TV to HDR mode when playing HDR." This is clearly not the case?

In my case, with my hardware, I use madVR with a 3DLUT and live with a subpar picture simply because I don't want to fumble around with settings and then put those settings back how they were when finished with playback because I'll forget. I also don't want to upgrade to limited special motherboards, CPU's, GPU's, etc for playback of UHD. While stripped UHD HDR mkv's play using anything but Kodi, only MPC allows UHD file structure. Other players require specific hardware and simply won't launch. Should the Windows HDR switch actually automate on and off somehow in the future (script and tagged preferred) it will be a better choice for me and complete the perfection.

Which 3DLUT are you using, is this the one created by a sensor for your TV ?
And the madVR display mode you are using is "Process HDR content by using 3DLUT" ?

My goal is to provide automation per movie and custom levels so every monitor will look its best. Also my goal is to provide auto hdr function switching by providing hdr.cal file to do it. powerdvd17 can read uhd movie and its metadata and send that metadata to tv to adjust hdr levels. Windows hdr tab is a generic hdr mode that sends hdr10. That's why some users have reported even with that tab switched the movie looks dull still. The tab is only part of the equation. The player must be able to open the video file and read the meta tag data and send it thru the hdmi port to the tv and the tv sees this formatted data and adjusts the levels. according to soli madvr can do this via passthru. Wish I could test this but amd shows a black screen in hdr10 mode. Only custom presenter filter works with amd.

I've tried Powerdvd17 with some HDR clips, they looked dull. So, I think Powerdvd17 doesn't work without the HDR tab switch that my htpc doesn't have of course.