if your response is to my post i'm not sure i follow?
i was asking about madvr only and its hdr pass through option.... is it possible to set all madvr setting set to "off" except for hdr pass through? or is madvr designed to do at least some rendering when launched, a minimum amount, which can't be changed, set lower, or tuned off?
re the future possibility of setting an external player to hdr only, sounds interesting, so how would that work exactly? would all sdr be tone mapped to hdr?
looking forward to reading your mpv thread.... from what i've read at github, plex forum, avsforum and elsewhere, getting mpv to handle hdr correctly has been a huge wish list item for quite a while, and because it apparently doesn't handle it correctly it's been a real deal breaker for more than a few who have opted to move on to other player options.
I think I understand your quandary, now. You seem to be assuming that all media is handled the same way? They aren't. Both in madVR and mpv, they are handled independently. SDR isn't necessarily converted to HDR. The most common use for madVR is for your display to be generally in SDR, and when HDR is presented, it then switches the display to HDR10 and the metadata is passed directly to the display for rendering. But if you run Windows in HDR10 (this is what I do), then you will always be in Wide Color Gamut and have brighter LEDs. Then the SDR colorspace will be applied to the WCG, and if not applied correctly you will have over saturation. I'm not sure how madVR handles that. In mpv, I use an icc so that mpv maps the colors, correctly. I'm not very experienced with all the madVR options, I've chosen to focus on mpv.
Here's an example of HDR passthrough compared to how I have mpv configured.