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What is HDR, anyway?

(www.lux.camera)
806 points _kush | 11 comments | 14 May 25 12:46 UTC | HN request time: 0s | source | bottom
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Terr_ ◴[14 May 25 23:21 UTC] No.43990206[source]▶
> Our eyes can see both just fine.

This gets to a gaming rant of mine: Our natural vision can handle these things because our eyes scan sections of the scene with constant adjustment (light-level, focus) while our brain is compositing it together into what feels like a single moment.

However certain effects in games (i.e. "HDR" and Depth of Field) instead reduce the fidelity of the experience. These features limp along only while our gaze is aimed at the exact spot the software expects. If you glance anywhere else around the scene, you instead percieve an unrealistically wrong coloration or blur that frustratingly persists no matter how much you squint. These problems will remain until gaze-tracking support becomes standard.

So ultimately these features reduce the realism of the experience. They make it less like being there and more like you're watching a second-hand movie recorded on flawed video-cameras. This distinction is even clearer if you consider cases where "film grain" is added.

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1. brokenmachine ◴[15 May 25 01:29 UTC] No.43990946[source]▶
I'm with you on depth of field, but I don't understand why you think HDR reduces the fidelity of a game.

If you have a good display (eg an OLED) then the brights are brighter and simultaneously there is more detail in the blacks. Why do you think that is worse than SDR?

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2. pfranz ◴[15 May 25 01:42 UTC] No.43991035[source]▶
Check out this old post: https://www.realtimerendering.com/blog/thought-for-the-day/

HDR in games would frequently mean clipping highlights and adding bloom. Prior the "HDR" exposure looked rather flat.

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3. Sharlin ◴[15 May 25 03:15 UTC] No.43991473[source]▶
The “HDR” here is in the sense of “tone mapping to SDR”. Should also be said that even “H” DR displays only have a stop or two of more range, still much less than in a real-world high-contrast scenes
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4. brokenmachine ◴[15 May 25 04:09 UTC] No.43991765[source]▶
It's still better though.

HDR displays are >1000nits while SDR caps out at less than 500nits even on the best displays.

Eg for the Samsung s90c, HDR is 1022nits, SDR is 487nits: https://www.rtings.com/tv/reviews/samsung/s90c-oled#test_608 https://www.rtings.com/tv/reviews/samsung/s90c-oled#test_4

Double the range is undeniably still better.

And also 10bit instead of 8bit, so less posterization as well.

Just because the implementations have been subpar until now doesn't mean it's worthless tech to pursue.

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5. brokenmachine ◴[15 May 25 04:17 UTC] No.43991796[source]▶
OK, so it doesn't mean real HDR but simulated HDR.

Maybe when proper HDR support becomes mainstream in 3D engines, that problem will go away.

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6. orthoxerox ◴[15 May 25 08:27 UTC] No.43992986{3}[source]▶
It's HDR at the world data level, but SDR at the rendering level. It's simulating the way film cannot handle real-life high dynamic range and clips it instead of compressing it like "HDR" in photography.
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7. majormajor ◴[15 May 25 14:37 UTC] No.43995552[source]▶
That's not what it means since 2016 or so when consumer TVs got support for properly displaying brighter whites and colors.

It definitely adds detail now, and for the last 8-9 years.

Though consumer TVs obviously still fall short of being as bright at peak as the real world. (We'll probably never want our TV to burn out our vision like the sun, though, but probably hitting highs at least in the 1-2000nit range vs the 500-700 that a lot peak at right now would be nice for most uses.

8. nomel ◴[15 May 25 20:56 UTC] No.43999261{4}[source]▶
> Instead of compressing it like "HDR" in photography

That's not HDR either, that's tone mapping to SDR. The entire point of HDR is that you don't need to compress it because your display can actually make use of the extra bits of information. Most modern phones take true HDR pictures that look great on an HDR display.

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9. pfranz ◴[15 May 25 23:27 UTC] No.44000379{3}[source]▶
Right. Just like the article, HDR is too vague to mean anything specific and a label that's slapped onto products. In gaming, it often meant they were finally simulating light and exposure separately--clipping highlights that would have previously been shown. In their opinion, reducing the fidelity. Same with depth of field blurring things that used to not have blur.
10. account42 ◴[23 May 25 11:16 UTC] No.44071781{5}[source]▶
That's revisionist nomenclature. HDR photography has meant tone mapping long before HDR displays existed.
11. account42 ◴[23 May 25 11:20 UTC] No.44071800{3}[source]▶
> HDR displays are >1000nits

Displays as low as 400nits have been marketed as "HDR".

But nits are only part of the story. What really matters at the end is the range between the darkest and brightest color the display can show under the lighting conditions you want to use it as. 400 nits in a darkened room where blacks are actually black can have much more actual range than 1000nits with very bright "blacks" due to shitty display tech or excessive external illumination.