JPEG transcoding is one of the neatest features of JXL; there is so much existing jpeg out there. Eventually that may be unnecessary, but it's looking like this could already save a significant amount of space for photo archive backups for example.

Great article!

Overall I am getting that AVIF is better on the web...unless Lossless is needed, in that case better take JPEGXL.

Perhaps useful:

* https://caniuse.com/?search=avif

* https://caniuse.com/?search=jpegxl

> AVIF is basically the keyframe format of AV1 video, with a bunch of still-image-specific optimisations thrown in. Animated AVIF however, is pretty much just a repackaging of AV1 video.

What optimizations are being added? I thought it was basically the exact same codec, but different packaging and usually some adjustment to how the encoder is tuned.

> AVIF is basically the keyframe format of AV1 video, with a bunch of still-image-specific optimisations thrown in. Animated AVIF however, is pretty much just a repackaging of AV1 video. You can convert an AV1 MP4 to AVIF and back losslessly - it's just a container change. That's why it performs so much better, because it's built for motion.

So, is animated AVIF only keyframes / p-frames, where each frame is independent from the other? I was under that impression, uncertain if there are any other capabilities it might have (like only updating part of the canvas when only parts change, like GIF supports)

I don't have any real use cases for jxl or avif or any other modern format b/c I rarely host images but all these articles are always so interesting to me. And at the end of it, I'm left wondering, is there ever going to be a single winner here?

The question now is how much of AVIF's advantage comes from the encoder compared to the image format itself. If it is the encoder, does JPEG XL even stand a chance of catching up? AVIF will certainly receive further improvements, albeit at a diminishing rate.

A little while ago, I chucked together a comparison game on image file formats (incl a stab at av2 images), encoders, parameters to back out preferences relative to ssimulacra2 and butteraugli: https://aadhar.sh/pixel-peeper

It does seem like AVIFs win on small images, and JXL gives you progressive rendering, easy upgradability on JPEGs, and better lossless and high bitrate images.

1. How long does size, encode time and resize take compared to good old jpeg?

2. Is it possible to encode AVIF with hardware acceleration?