jpegli

For making compact high-quality jpeg files, consider trying jpegli[1], it does an impressive job. More specifically, if I try a bunch of AVIF quantization options and manually pick the one that appears visually lossless, it beats jpegli, but if I select a quantization option that always looks visually lossless with AVIF, jpegli will win the average size, because I need to use some headroom for images that AVIF does less well on. 1: https://github.com/google/jpegli

Can I ask which browser you're using? I was unable to reproduce the exact same issue you described here on Firefox 128 on Linux... however, you're definitely onto something! It's a combination of two subtle issues: 1) A known bug in the jpegli library. As you suspected, XYB mode combined with chroma subsampling (like the old 4:2:0 default) can cause the exact "downscaled" look you saw. [0] 2) A sizing bug in my decoder pipeline. I was mistakenly using an image's internal codedWidth instead of its final displayWidth. For some WebP/AVIF files, this created a smaller image on a larger canvas, which magnified the XYB bug. I've just pushed a fix that addresses both issues. I've also updated the defaults to what I believe is a much better starting point: Quality 80, XYB, and 4:4:4 subsampling. This combination avoids the bug while still leverag

FWIW, the day I discovered jpegli[1] I left WebP behind. Similar sizes to WebP while maintaining JPEG compatibility. 1: https://github.com/google/jpegli

Not for a long time. The WebP encoder has improved a lot since MozJPEG was released. But these days we have Jpegli [1] which beats WebP at higher quality levels. [1] https://github.com/google/jpegli/

Technically it also had a fourth :^) [0] but it was spun out into a separate project of its own, jpegli [1]: JPEG but it uses some tricks from JPEG XL. These include spatially adaptive quantization, quantization matrices that better preserve psychovisual detail, more efficient color spaces, and also HDR (10+ bit depth) support [2]. [0] https://github.com/libjxl/libjxl/tree/main/lib/jpegli [1] https://github.com/google/jpegli [2] https://opensource.googleblog.com/2024/04/introducing-jpegli...