A new PNG spec

#1

Post by bluedel » Tue, Jun 24, 2025, 1:01 PM UTC

A new PNG spec
programmax.net

Re: A new PNG spec

#2

Post by bravesoul2 » Tue, Jun 24, 2025, 1:16 PM UTC

Papua New Guniea never went away!

Re: A new PNG spec

#3

Post by LeoPanthera » Wed, Jun 25, 2025, 5:06 AM UTC

> I know you all immediately wondered, better compression?. We're already working on that.

This worries me. Because presumably, changing the compression algorithm will break backwards compatibility, which means we'll start to see "png" files that aren't actually png files.

It'll be like USB-C but for images.

Re: A new PNG spec

#4

Post by LegionMammal978 » Wed, Jun 25, 2025, 5:06 AM UTC

Reading the linked blog post on the new cICP chunk type [0], it looks like the "proper HDR support" isn't something that you couldn't already do with an embedded ICC profile, but instead a much-abbreviated form of the colorspace information suitable for small image files.

[0] https://svgees.us/blog/cICP.html

Re: A new PNG spec

#5

Post by albert_e » Wed, Jun 25, 2025, 5:09 AM UTC

So animated GIFs can be replaced by Animated PNGs with alpha blending with transparent backgrounds and lossless compression! Some nostalgia from 2000s websites can be revived and relived :)

Curious if Animated SVGs are also a thing. I remember seeing some Javascript based SVG animations (it was a animated chatbot avatar) - but not sure if there is any standard framework.

Re: A new PNG spec

#6

Post by skywal_l » Wed, Jun 25, 2025, 5:10 AM UTC

LeoPanthera wrote: post #3

> I know you all immediately wondered, better compression?. We're already working on that. This worries me. Because presumably, changing the compression algorithm will break backwards compatibility, which means we'll start to see "png" files that aren't actually png files. It'll be like USB-C but for images.

Can't you improve a compression algorithm and still produce a still valid decompression input? PNG is based on zip, there's certainly ways to improve zip without breaking backwards compatibility.

That being said, they also can do dumb things however, right at the end of the sentence you quote they say:

> we want to make sure we do it right.

So there's hope.

Re: A new PNG spec

#7

Post by lifthrasiir » Wed, Jun 25, 2025, 5:11 AM UTC

LeoPanthera wrote: post #3

> I know you all immediately wondered, better compression?. We're already working on that. This worries me. Because presumably, changing the compression algorithm will break backwards compatibility, which means we'll start to see "png" files that aren't actually png files. It'll be like USB-C but for images.

Better compression can also mean a new set of filter methods or a new interlacing algorithm. But yeah, any of them would cause an instant incompatibility. As noted in the relevant issue [1], we will need a new media type at the very least.

[1] https://github.com/w3c/png/issues/39#issuecomment-2674690324

Re: A new PNG spec

#8

Post by andsoitis » Wed, Jun 25, 2025, 5:14 AM UTC

albert_e wrote: post #5

So animated GIFs can be replaced by Animated PNGs with alpha blending with transparent backgrounds and lossless compression! Some nostalgia from 2000s websites can be revived and relived :) Curious if Animated SVGs are also a thing. I remember seeing some Javascript based SVG animations (it was a animated chatbot avatar) - but not sure if there is any standard framework.

> Curious if Animated SVGs are also a thing.

Yes. Relevant animation elements:

•

See https://www.w3schools.com/graphics/svg_animation.asp

Re: A new PNG spec

#9

Post by adgjlsfhk1 » Wed, Jun 25, 2025, 5:17 AM UTC

I'm very curious to see how this will end up stacking up vs lossless jpegxl

Re: A new PNG spec

#10

Post by qwertox » Wed, Jun 25, 2025, 5:19 AM UTC

> Officially supports Exif data

Probably the best news here. While you already can write custom data into a header, having Exif is good.

BTW: Does Exif have a magnetometer (rotation) and acceleration (gravity) field? I often wonder about why Google isn't saving this information in the images which the camera app saves. It could help so much with post-processing, like with leveling the horizon or creating panoramas.