←back to thread

A new PNG spec

(www.programmax.net)
616 points bluedel | 2 comments | 24 Jun 25 13:01 UTC | HN request time: 0.425s | source
Show context
LeoPanthera ◴[25 Jun 25 05:06 UTC] No.44373778[source]▶
> 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.

replies(11): >>44373790 #>>44373796 #>>44373928 #>>44373937 #>>44374139 #>>44374147 #>>44374842 #>>44375132 #>>44375261 #>>44375615 #>>44380021 #
lifthrasiir ◴[25 Jun 25 05:11 UTC] No.44373796[source]▶
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

replies(2): >>44374822 #>>44374939 #
snvzz ◴[25 Jun 25 08:14 UTC] No.44374822[source]▶
I am hopeful whatever better compression doesn't end up multiplying memory requirements, or increase burden on cpu, especially on decompression.

Now, PNG datatype for AmigaOS will need upgrading.

replies(2): >>44374936 #>>44375008 #
Arnt ◴[25 Jun 25 08:47 UTC] No.44375008[source]▶
I don't see why? If your video output is plain old RGB (like the Amiga hardware), then an unmodified decoder will handle new files without a problem. You only need a new decoder if your video output can handle more vivid colours than RGB can express.
replies(1): >>44376534 #
1. Findecanor ◴[25 Jun 25 12:31 UTC] No.44376534[source]▶
An image decoded in the wrong colour space for the output will look wrong. It is not using extra bits to express the increased dynamic range: the existing numeric range is stretched and warped.
replies(1): >>44379844 #
2. Arnt ◴[25 Jun 25 17:34 UTC] No.44379844[source]▶
Yes. But how bad? AIUI the way it's done is more or less the best that can be done with old video hardware, like mine and like the Amiga.

It could be horrible in principle, but actually isn't.