[acdha]

WebP was the classic Google “ship the prototype” move - they were hoping Chrome could muscle it through but it delivered only modest compression improvements (10-15% real world - the marketing papers promised 30% based on comparisons to unoptimized JPEGs) but it was missing features and had very primitive software support, making it harder to produce, deliver, or share (when Facebook switched, a common complaint was someone downloading a picture and finding it didn’t work in another app or when they sent it to a friend).

Very few sites pay for so much outgoing image bandwidth to make that compatibility cost lower than a 15% savings.

[asddubs]

it's still a version of jpeg that supports transparency, and it's actually well supported (down to ios 14) to use without also having to deliver a fallback format now. it's not as good as it's successors, but if you are chosing one format and care about image size, it's the best choice.

[acdha]

I’m not saying it was terrible but that it took a long time for it to be worth the trouble unless you really needed transparency. It’s only been the last year or so that you could expect to be able to use it for anything non-trivial and not spend time dealing with tools which didn’t support it.

[asddubs]

it did, but mostly because safari dragged its feet for years. Thank god they didn't take this long for AVIF (though I would have loved it if they had shipped AVIF in io15, since a bunch of devices won't get ios16)

[acdha]

Safari was the least of it - most image processing tools didn’t support it (e.g. PhotoShop got support last year, Microsoft Paint was the year before) or you had to do things like recompile the versions of common tools to add support (again, better now but it takes a while for support to spread through Linux distribution releases), and now you have more security exposure. That was a lot of hassle for very modest compression gains.

AVIF has gone better because it wasn’t based on a video codec which was never really competitive, was developed collaboratively, and didn’t have feature regressions from JPEG. As with tool support, that last matters a lot at many organizations because the edge experience tends to decide things - even if 95% of your usage is boring 8-bit 4:2:0 the institutional memory tends to be shaped by the times you hit something which can’t be used without more work. If it compressed as well as AVIF, more people might have decided WebP was worth it but since it only marginally outperformed JPEG the case was never that strong.

Part of what I meant by “shipping the prototype” was this kind of stuff: someone at Google wanted to find another use for the On2 IP they’d purchased so they tossed it into a 20 year old container format and shipped it. As with WebM, the benchmarks were fast and loose which meant that anyone who replicated them saw substantially lower performance, which is another great way not to build confidence in your format.

[xena]

AVIF works on safari on iOS 15. Open the browser inspector on a blogpost on xeiaso.net and you'll see that it's selecting an AVIF image.