What is HDR, anyway?

It's from the perspective of still photography, video, film, desktop computing, decades of research papers, and hundreds of years of analog photography, condensed into something approachable.

> However in the much broader context of HN, a highly technical community whose interests in imaging are diverse, the article's content level and narrow focus aren't consistent with the headline title. It seems written at a level appropriate for novice users.

"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity"

To be clear, I didn't submit the post, and I never submit my posts. I don't care if my posts make a splash here, and kind of dread when they do because anything involving photography or video attracts the most annoying "well actually" guys on the Internet.

> When I saw the post's headline I thought "Cool! We really need a good technical deep dive into the mess that is HDR - including tech, specs, standards, formats, content acquisition, distribution and display across content types including stills, video clips and cinematic story-telling and diverse viewing contexts from phones to TVs to cinemas to VR."

The post is called, "What is HDR," and the introduction explains the intended audience. That audience is much larger than "people who want to read about ITU-R Recommendation BT.2100." But if you think people are interested in a post like that, by all means write it.

You can lie as much as you like as an advertiser. At the beginning, HD meant 1080p. Then, 1080p became FullHD, only that 720p to became HD and to make HD digital television possible. (the original SD television is worse than analog)

I'm very confused by this. From what I've seen it's been getting a lot better (since transitioning from CRTs). At least for television, frame-rate matching is becoming more of a thing. Higher frame rates really help. Calling everything fps for simplicity; 120 divides evenly by 24, 30, and 60. Lower values wont match and cause issues.

Similarly, (maybe back in the 90s?) projectors in theaters would double-expose each frame to reduce the flicker in between frames. With digital, they no longer have to advance the film between frames.

> smooth motion like credits at certain speeds are extremely uncomfortable to look at at these frame rates.

I think scrolling credits are the most difficult use case: white on black with hard text and no blur. DLP projectors (common 10+ years ago) drive me nuts displaying R G and B separately.

Outside of credits, cinematographers and other filmmakers do think about these things. I remember hearing a cinematographer talk about working on space documentaries in Imax. If you panned too quickly, the white spaceship over a black star field could jump multiple feet each frame. Sure films shot today are optimized for the theater, but the technology gap between theater and home is nowhere near as crazy as CRT vs acetate.

> Frame size is different from the other parameters, as it is solely a physical practicality.

I'm still struggling to see how its that different. Widescreen meant a lower effective resolution (it didn't have to--it started with Cinerama and Cinemascope), but was adopted for cost and aesthetic reasons.

> If some technology somewhere else in the stack causes a change…and soon all content aligns on the format, and the majority of home TV sets will be shaped to fit the majority content it can receive.

And the industry and audiences are really attached to 24fps. Like you say, home televisions adopted film's aspect ratio and I've also seen them adopt much better support for 24fps.

As kind of an aside, I wonder if the motion blur is what people are attached to more than the actual frame rate. I assume you're talking about frame rates higher than 30? Sure, we have faster films and brighter lights, but exposure time is really short. I saw the Hobbit in theaters in both high frame rate and 24fps and the 24fps one looked weird to me, too--I meant to look it up, but I assume they just dropped frames making the blur odd.

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.