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Comment by neoberg | Hacker News Reader

> HDR is just a marketing term for software that increases the colour and black saturation of content beyond the actual input. For photography that means more saturation than what you see in real life, for video that means tweaking it after you receive the signal.

Not even remotely correct. It is definitely not a marketing term. HDR is set of specifications and formats for capturing, storing and displaying visual data with a higher than "Standard" dynamic range. It basically carries more data and it requires proper color management. It has to be supported by relevant drivers and the display server. Right now there is no way to view HDR content (video, photos or games) under Linux.

If you are interested; there is some effort going on to enable this but it will probably take a couple more years.

https://gitlab.freedesktop.org/wayland/wayland-protocols/-/m...

https://gitlab.freedesktop.org/pq/color-and-hdr

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https://www.veneratech.com/hdr-dolby-vision-meta-data-parame....

"HDR" is just metadata to pass along to the device to tell it how to optimally adjust the colours (or not adjust them). It's main use seems to be so that HDR displays can oversaturate "SDR" content in HDR mode.

> carries more data

Not really. The metadata isn't more colours or something, it just passes info to the device about certain aspects of the video.

HDR content will be HDR if the display has enough range regardless of whether or not the OS has HDR "mode". It's more about adjusting all the other content.

Dunno if you ever had a plasma TV back in the day but they could display way more contrast than LCDs of the day so you could adjust the settings to change the way all content looks. HDR metadata is basically that, but on a per-video basis. Useful enough but not some game changer... Which is why there's tons of articles about what HDR does and doesn't do.

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.

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

HDR hasn't always meant 10 bit colour...

But anyhow, Ubuntu supports 10 bit colour and has for awhile:

https://wiki.ubuntu.com/DeepColourDepthSupportPlan

HDR as we know today always meant 10 bit colour. Before that some screens emulated HDR in 8 bit color by doing dithering to -poorly- create the illusion of a wider luminance range.

edit: and 10 bit color support on its own is not enough for HDR. I mean I don't know why we are even discussing this honestly. HDR under Linux is not supported at all. It's not an opinion; it's an objective fact which you can confirm in a couple of different ways. You can not view HDR content if you're using Linux no matter what content or display you have. There is an active effort in the community to have HDR support in Linux but it will take a couple more years probably.

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