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A new PNG spec

(www.programmax.net)
614 points bluedel | 3 comments | 24 Jun 25 13:01 UTC | HN request time: 0.628s | source
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Joel_Mckay ◴[25 Jun 25 06:05 UTC] No.44374066[source]▶
DaVinci Resolve also supports OpenEXR format with the added magic of LUT.

PNG is popular with some Commercial Application developers, but the exposure and color problems still look 1980's awful in some use-cases.

Even after spending a few grand on seats for a project, one still gets arrogant 3D clown-ware vendors telling people how they should run their pipeline with PNG hot garbage as input.

People should choose EXR more often, and pick a consistent color standard. PNG does not need yet another awful encoding option. =3

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DidYaWipe ◴[25 Jun 25 07:41 UTC] No.44374614[source]▶
"PNG is popular with some Commercial Application developers, but the exposure and color problems still look 1980's awful in some use-cases."

What are you talking about? It's a bitmap. It has nothing to do with "exposure and color problems."

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Joel_Mckay ◴[25 Jun 25 08:08 UTC] No.44374785[source]▶
In general, with some applications people hit the limits pretty quickly with PNG and JPG. In our use-case, the EXR format essentially meant a rendered part of the source image wouldn't be "overexposed" by the render pipeline, and layers could be later adjusted to better match in Resolve. Example: your scenes fireball simulation won't look like a fried egg photo from 1980 due to hitting 0xFF.

If you've never encountered the use-case, than don't worry about the aesthetics. Seriously, many vendors also just don't care... especially after they already were paid. Best of luck =3

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ProgramMax ◴[25 Jun 25 18:36 UTC] No.44380512[source]▶
0xFF is 8-bit. PNG supports up to 16-bit. It always has. Plus, PNG now supports full HDR so the fireball won't look washed out.

I think your experience is with some tool that made bad PNGs. That is a problem with the tool, not the format.

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1. Joel_Mckay ◴[25 Jun 25 19:00 UTC] No.44380766[source]▶
EXR stores the color-space information differently, and you missed the point.

Have a look at a tutorial that dives into the basic details, and consider learning something:

https://www.youtube.com/watch?v=pLt1230dtYE

https://www.youtube.com/watch?v=mb0b83MML78

https://www.youtube.com/watch?v=egtnkhuUe_E

PNG has its use-cases, and some people do expect that baked color-space garbage look given it dominates a lot of low-end media. Have a great day =3

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2. ProgramMax ◴[25 Jun 25 19:46 UTC] No.44381198[source]▶
I'm trying to follow your point. But...there are problems with your claims. Yes, EXR stores color-space differently than PNG. Because EXR doesn't store color space at all.

In the first video, the person loads the image and manually chooses a gamma transfer function with 2.2. If that was then saved, it would produce the washed-out fireball you mentioned.

In the second video, the person loads the image and manually chooses rec.709, which is also gamma tf and also produces washed-out fireball. In fact, the EXR image he loads literally has a bright fireball and you see it get washed out.

If you want to make claims about EXR being better than PNG, you need to say why storing the values as floating point is better than integer. But the blown-out fireball example is just incorrect. As evidence, I'll point to HDR. ANYTHING you see in an HDR movie is now 100% losslessly reproducible in a PNG.

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3. Joel_Mckay ◴[25 Jun 25 20:04 UTC] No.44381326[source]▶
There is a lot of conflated contexts to unpack there...

However, I still trust the ILM engineers over your pet project, and maligned post that reeks of LLM slop.

The argument of making cow from hamburger doesn't hold true under our use-cases. You were shown the path, and it is your choice to put in the work to learn something important.

Best of luck kid =3