Confused with HDR

[Vamp898]

I hope this is the right forum to ask this question, but i am completely confused with how HDR works on PCs.

I ripped my very first 4K HDR BluRay and it looks good... and that confused me, it is supposed to look bad.

My Notebook does have an HDR compatiable GPU and so Windows says, it can do HDR. But(!), my Display is only an SDR Display, no HDR support and Windows tells me that. GPU yes, Display no. So people told me when i play an HDR MKV, it will look very flat and the colors will look off.

But it looks amazing. It looks exactly how i am used to how HDR looks on my HDR capable TV. When i take a screenshot with the VLC screenshot feature, that screenshot looks flat and the colors are very weak, exactly how people describe it. But the actual video looks fine to me when playing it.

I tried to play it with PowerDVD 22 too which complains about that HDR is not supported on my system and warns me, that everything will look wrong but then, when i ignore the warning, it looks just as it is supposed to be.

I can switch between Hardware Rendering and Software Rendering in PowerDVD and when i click that switch, i have this flat and colorless image for like 1 second, and then it turns back to normal. And there is a visible difference between Software and Hardware (the colors are stronger and pop more, but they are unnatural strong imho).

That is my issue, why does it look good? Is my GPU causing this, knowing its an SDR Display and then adjusting the output? I don't get it. It looks good to the point, that i could, i am pretty sure, trick people into thinking its an HDR Display.

[Billycar11]

Most programs now tone map hdr to sdr so it looks ok
In the old days that was not common

[Vamp898]

Ah okay. So they basically do the same that you do with photos (cameras shoot with 14-16bit and still, you output an 8bit JPEG in the end) which makes sense.

My display only has an contrast of 300something:1, so 8bit is completely sufficient but I think I'll consider an HDR Display in the long run to at least be able to display 10bit

[dcoke22]

There's a display standard called VESA DisplayHDR that can help you navigate the murky waters of HDR displays.