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Firefox 157 will include JPEG XL by default on all platforms

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Re: Firefox 157 will include JPEG XL by default on all platforms

#12
post #7
post #2

I'm curious how many HN people in 2026 have not yet heard of JPEG XL / jxl

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

It compresses better than webp*, has really good progressive decoding (current encoders are able to encode the image such that the most important part of the image gets decoded first, and you only need the first ~20% of the image to display it as a thumbnail), and it's also a very flexible format (unlike avif) since it can also display lossless files* and display much larger images than AVIF can.

Also the compatibility with existing JPEG files that was mentioned below, unlike other formats you can losslessly convert a JPEG into a JXL without losing quality but saving file size in the process.

* it actually has better compression than PNG for this

* and potentially AVIF too, but this is debated

Re: Firefox 157 will include JPEG XL by default on all platforms

#14
post #7
post #2

I'm curious how many HN people in 2026 have not yet heard of JPEG XL / jxl

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

Lossless: stronger than both (even though webp was pretty good there), especially AVIF that can't really do lossless RGB (must convert to YUV or incur a really bad compression ratio) yet relatively fast encoding.

Lossy: webp (VP8 I-frame format which means mandatory 4:2:0 chroma subsampling and ungodly smoothing) was never good, AVIF is better but only equal or worse at decent, visually transparent bitrates.

Another point worth mentioning: AV1/AVIF doesn't really have a standard encoder, libaom is a reference codec thus slow and not really interested in proper psy optimizations, SVT-AV1 is slowly getting there thanks to enthusiasts porting x264's good stuff to it but remains locked to 4:2:0 (lol). I won't even speak about the missed promises of FGS.

And finally, JXL's format has a lot of gizmos that make it more future proof as something to replace JPEG/PNG/GIF. Progressive decoding, lossless conversion from JPEG, very large limits (float bitdepth for HDR, image dimensions without tiling, unlimited channels incl. CMYK support) are good even when the encoder isn't yet supporting everything.

Re: Firefox 157 will include JPEG XL by default on all platforms

#15
post #12
post #7

Earlier quoted context omitted.

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

It compresses better than webp*, has really good progressive decoding (current encoders are able to encode the image such that the most important part of the image gets decoded first, and you only need the first ~20% of the image to display it as a thumbnail), and it's also a very flexible format (unlike avif) since it can also display lossless files* and display much larger images than AVIF can. Also the compatibili…

avif also supports lossless, but it's so inefficient it might as well not exist.

Lossless webp is a completely different image format compared to lossy webp, even though they come under the same file extension. Unlike lossy webp, it's a good image format that has excellent compression ratio compared to png. I've often been using it for screenshots to avoid damaging text clarity and still maintain acceptable file size.

jxl has excellent support for both lossy and lossless cases, and can replace both lossy avif (even if somewhat less efficient at low file sizes), and lossless webp.

Note also that converting jpeg to jxl is 100% reversible, you can convert it back to exactly the same image (byte for byte identical) if you need to.

Re: Firefox 157 will include JPEG XL by default on all platforms

#17
post #7
post #2

I'm curious how many HN people in 2026 have not yet heard of JPEG XL / jxl

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

At the basic job of showing a normal 24bpp photo on screen, the differences between the formats are marginal.

jxl shines when you want to do anything even a little bit more complex. Support for lots more color formats, including fp ones. Support for an image with parts of it encoded losslessly, and parts with a lossy encoder. Great progressive decoding. And many more features.

Re: Firefox 157 will include JPEG XL by default on all platforms

#18
post #10
post #7

Earlier quoted context omitted.

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

The big feature over other new formats is compatibility with legacy JPEGs. You can (simplified) take the raw data from a legacy JPEG, reformat it as a JPEG XL, and achieve like 20-30% filesize savings without any actual re-encode, just better packaging of the same data. While converting them to AVIF or webp is a lossy re-encode, and so loses quality. I think it's really this feature that has people wanting it still d…

Webp lossy is better (compresses more with higher quality image results) than jpeg at everything except smooth gradients at high quality settings according to the research I remember doing. Webp lossy can't seem to get rid of banding until you go ultra high quality settings. Jpeg can show blue skies without banding at much more reasonable quality settings. So webp is better at anything where smaller files is preferred, like all website usage. Jpeg is better for long term storage of very high quality lossy compressed images.

I chose webp for long term storage of scanned documents in our SaaS product, as size reduction was more important than no banding.

Also webp has excellent support in modern software and operating systems. So that's not a drawback any more. JpegXL will be the best of all worlds choice in a few years when software support is good.

Re: Firefox 157 will include JPEG XL by default on all platforms

#19
post #12
post #7

Earlier quoted context omitted.

I have only heard of it in passing. I wonder what it adds beyond Webp and Avif.

It compresses better than webp*, has really good progressive decoding (current encoders are able to encode the image such that the most important part of the image gets decoded first, and you only need the first ~20% of the image to display it as a thumbnail), and it's also a very flexible format (unlike avif) since it can also display lossless files* and display much larger images than AVIF can. Also the compatibili…

> [JPEG XL can] display much larger images than AVIF can

Does it do tiles? What about pyramids (i.e. precomputed downscaled images, think mipmaps)? Right now the state of the art for truly large images (medical, geospatial, scanned artworks) seems to be JPEG (and I think also JPEG 2000?) tiles in TIFF containers, which would be fine except nobody seems to agree on how exactly to express the pyramids.

Re: Firefox 157 will include JPEG XL by default on all platforms

#20
post #5

With both Firefox and Chromium using jxl-rs (Rust-based), I wonder what Apple will do about the libjxl (C++) they already shipped. I know they're doing some memory-safety with Swift, but are they shipping any Rust in their platforms so far? I also wonder if anyone's done benchmark comparisons between both libs. -- Also, I was under the impression that after backtracking, Chromium was relying on Mozilla to come up wit…

Apple is gonna do what apple wants.
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