You're getting somewhere but still not complete. HDR formats we have today use 10bit or 12bit bit depths so that alone is a big difference. About the metadata, HDR10 uses static metadata meaning whole content will have the same metadata but HDR10+ and Dolby use dynamic metadata.

HDR content "will not" be HDR if you're playing it under Linux. It will however be HDR if you play it under Macos or Windows (keeping everything else like the screen and content same). There is no way around this right now. So in basic terms you will not see the dark blacks and bright whites under Linux.

> Edit - where HDR really is great is photography... You take multiple photos of the same scene with different ISO and shutter settings then stitch them together for more colours than would otherwise be captured. But a screen can either display colours or it can't.

It's the same for video or games really. With HDR you can record and display more details and contrast.

And that HDR photo you just described will not be shown as HDR even if your display supports HDR if viewed under Linux