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Jpeg XL isn’t backwards compatible with existing JPEG renderers. If it was, it’d be a winner.
According to the video, and this article, JPEG XL is backwards compatible with JPEG.
But I’m not sure if that’s all that necessary. JPEG XL was designed to be a full, long term replacement to JPEG. Old JPEG’s compression is very lossy, while JPEG XL, with the same amount of computational power, speed, and size, outclasses it entirely. PNG is lossless, and thus is not comparable since the file size is so much larger.
JPEG XL, at least from what I’m seeing, does appear to be the best full replacement for JPEG (and it’s not like they can’t co-exist).
It’s only backwards compatible in that it can re-encode existing jpeg content into the newer format without any image loss. Existing browsers and apps can’t render jpegXL without adding a new decoder.
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.
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.
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.
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.
The video actually references that comic at the end.
But I don’t see how that applies in your example, since both JPEG and JPEG XL existing in parallel doesn’t really have any downsides, it’d just be nice to have the newer option available. The thrust of the video is that Google is kneecapping JPEG XL in favor of their own format, which is not backwards compatible with JPEG in any capacity. So we’re getting a brand new format either way, but a monopoly is forcing a worse format.
They’re confusing backwards and forwards compatible. The new file format is backwards compatible but the old renderers are not forward compatible with the new format.
According to the video, and this article, JPEG XL is backwards compatible with JPEG.
But I’m not sure if that’s all that necessary. JPEG XL was designed to be a full, long term replacement to JPEG. Old JPEG’s compression is very lossy, while JPEG XL, with the same amount of computational power, speed, and size, outclasses it entirely. PNG is lossless, and thus is not comparable since the file size is so much larger.
JPEG XL, at least from what I’m seeing, does appear to be the best full replacement for JPEG (and it’s not like they can’t co-exist).
It’s only backwards compatible in that it can re-encode existing jpeg content into the newer format without any image loss. Existing browsers and apps can’t render jpegXL without adding a new decoder.
Why is that a negative?
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.
But how is that different to any other new format? Webp was no different?
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.
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.
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.
https://xkcd.com/927/
The video actually references that comic at the end.
But I don’t see how that applies in your example, since both JPEG and JPEG XL existing in parallel doesn’t really have any downsides, it’d just be nice to have the newer option available. The thrust of the video is that Google is kneecapping JPEG XL in favor of their own format, which is not backwards compatible with JPEG in any capacity. So we’re getting a brand new format either way, but a monopoly is forcing a worse format.
They’re confusing backwards and forwards compatible. The new file format is backwards compatible but the old renderers are not forward compatible with the new format.