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A new PNG spec

(www.programmax.net)
615 points bluedel | 1 comments | 24 Jun 25 13:01 UTC | HN request time: 0s | source
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qwertfisch ◴[25 Jun 25 12:22 UTC] No.44376468[source]▶
Seems a bit too late? And also, JPEG XL supports all the features and uses already advanced compression (finite-state entropy, like ZStandard). It offers lossy and lossless compression, animated pictures, HDR, EXIF etc.

There is just no need for a PNG update, just adopt JPEG XL.

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Aachen ◴[25 Jun 25 12:55 UTC] No.44376756[source]▶
> advanced compression (finite-state entropy, like ZStandard)

I've not tried it on images, but wouldn't zstandard be exceedingly bad at gradients? It completely fails to compress numbers that change at a fixed rate

Bzip2 does that fine, not sure why https://chaos.social/@luc/114531687791022934 The two variables (inner and outer loop) could be two color channels that change at different rates. Real-world data will never be a clean i++ like it is here, but more noise surely isn't going to help the algorithm compared to this clean example

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1. adgjlsfhk1 ◴[25 Jun 25 14:06 UTC] No.44377519[source]▶
the FSE layer isn't responsible for finding these sorts of patterns in an image codec. The domain modeling turns that sort of pattern into repeated data and then the FSE goes to town on the output.