from what i can tell they're doing some tricks with visual perception scores and then crunching numbers over a huge hoard of photographs and using that to train heuristics. seems to work quite well https://github.com/danielgtaylor/jpeg-archive
there is another one called adept that is based on some analysis stuff that i couldn't build https://github.com/technopagan/adept-jpg-compressor it does some kind of edge analysis and then quantizes that to make a bitmap of where to use high and low quality encoding.
i don't know if the webp encoders are this advanced and i'm fairly sure the jxl ones are not. when i tested jxl it actually gets pretty competitive size performance to webp despite ... being seemingly massively less complicated
shame we'll never get to use it.
💀
@icedquinn
That "adaptive JPG Compressor" is a complete joke.
His preview image weighs in at 196kb, and has so much destroyed details in the hair, and smudgy, blurry compression artifacts in the background, that it's not even funny.
I downloaded his preview png, saved it as 92% jpeg in Gimp, takes up only 116kb, and still looks better in every way.
Either he fucked up his preview images without realizing, or his script is a complete farce.
@icedquinn
I'm looking at his other examples, and it still doesn't look favorably for his script.
soccer looks good, but there is no significant difference in size, and they look the same anyway.
I did find a small visual improvement in satchel, in a very small area, but the ruined background is far more jarring, and would distract too much in a normal viewing the notice an improvement in an area the size of a small coin. Same file size though.
He doesn't give a png for these others. Just q85 versions from other encoders.
Seems like a waste of space. I'm not seeing anything of use, just a rediscovery of what jpeg is supposed to do in the first place, and what other formats surely improved upon already.
We need to ditch jpeg, not try to retrofit useless algorithms that barely do something, and when they do, they worsen the image.
@icedquinn
On beach I do notice a slight decrease in the typical jpeg artifacts around edges (in some places), but in exchange is shits out artifacts everywhere else. There is a decent file size decrease, but it's just not worth it at all.