It's based on the next-gen AV1 video codec. I've tried it out, and it's amazing.

https://netflixtechblog.com/avif-for-next-generation-image-c...

https://github.com/AOMediaCodec/libavif

> So what's this AVIF format they mention that's actually better than both?

AVIF is an image format based on the intra-frame coding of AV1, as WebP is to VP8 and HEIF is to HEVC.

AV1 and HEIF are super recent though, the AVIF 1.0 spec was only released in early 2019. By comparison, WebP was initially released in 2019. So AVIF currently has very little support (it's behind flags in Firefox and that's it).

However all the big names are part of AOM, which oversees AV1 (and AVIF): http://aomedia.org/membership/members/

So chances are pretty high it'll get widespread support, eventually.

There’s one problem though: like WebP, AVIF just is not solving a big issue.

I think it's just about to take off. Browser support across the board is coming by the end of the year. PNG also took a while to become fully supported, so we just need some patience.