• seaQueue@lemmy.world
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    4 months ago

    Legacy client support. Old devices running old browser code can’t support a new format without software updates, and that’s not always possible. Decoding jxl on a 15yo device that’s not upgradable isn’t good UX. Sure, you probably can work around that with slow JavaScript decoding for many but it’ll be slow and processor intensive. Imagine decoding jxl on a low power arm device or something like a Celeron from the early 2010s and you’ll get the idea, it will not be anywhere near as fast as good old jpeg.

    • ProdigalFrog@slrpnk.netOP
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      4 months ago

      That’s a good argument, and as a fan of permacomputing and reducing e-waste, I must admit I’m fairly swayed by it.

      However, are you sure JPEG XL decode/encode is more computationally heavy than JPEG to where it would struggle on older hardware? This measurement seems to show that it’s quite comparable to standard JPEG, unless I’m misunderstanding something (and I very well might be).

      That wouldn’t help the people stuck on an outdated browser (older, unsupported phones?), but for those who can change their OS, like older PC’s, a modern Linux distro with an updated browser would still allow that old hardware to decode JPEG XL’s fairly well, I would hope.

      • seaQueue@lemmy.world
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        4 months ago

        Optimized jpegxl decoding can be as fast as jpeg but only if the browser supports the format natively. If you’re trying to bolt jxl decoding onto a legacy browser your options become JavaScript and WASM decoding. WASM can be as fast but browsers released before like 2020 won’t support it and need to use JavaScript to do the job. Decoding jxl in JavaScript is, let’s just say it’s not fast and it’s not guaranteed to work on legacy browsers and older machines. Additionally any of these bolt on mechanisms require sending the decoder package on page load so unless you’re able to load that from the user’s cache you pay the bandwidth/time price of downloading and initializing the decoder code before images even start to render on the page. Ultimately bolting on support for the new format just isn’t worth the cost of the implementation in many cases so sites usually implement fallback to the older format as well.

        Webp succeeded because Google rammed the format through and they did that because they controlled the standard. You’ll see the same thing happen with the jpegli format next, it lifts the majority of its featureset from jpegxl and Google controls the standard.