Hi Kagami, What questions do you think you would answer with a prototype? It seems like this is about getting an implementation in place in preparation for shipping, but not committing to shipping. That's a good plan in this case.
I've discussed this with Jake and my understanding is that the Rust implementation is currently about 2x slower than the (unsafe) C++ reference implementation. That doesn't seem like it would be good for Firefox, especially since the C++ implementation is still substantially slower than decoders for other formats. At what point would we think the code is fast enough to ship? Are there other things that a prototype might need to resolve before shipping? Features in the format we might need extra capabilities to support, like progressive rendering or wide gamut or anything in the long list of features for the format? On Tue, Jan 27, 2026 at 12:23 AM 'Kagami Rosylight' via [email protected] <[email protected]> wrote: > (The previous intent in 2021 is here > <https://groups.google.com/a/mozilla.org/g/dev-platform/c/wdB1v7sKcdo>.) > > *Summary*: JPEG XL is a new emerging image format that has been adopted > by multiple software > <https://en.wikipedia.org/wiki/JPEG_XL#Official_software_support> as of > 2026. The format is now getting an alternative, more memory-safe > implementation <https://github.com/libjxl/jxl-rs> written in Rust. > *Bug*: https://bugzilla.mozilla.org/show_bug.cgi?id=1986393 > *Specification*: https://www.iso.org/standard/85066.html > *Standards Body*: ISO/IEC > *Platform coverage*: All > *Preference*: image.jxl.enabled > *Link to standards-positions discussion*: > https://github.com/mozilla/standards-positions/issues/522 > *Other browsers*: > > - Blink: Implemented with the same underlying Rust library behind the > preference #enable-jxl-image-format. Their intent to prototype is > updated > > <https://groups.google.com/a/chromium.org/g/blink-dev/c/WjCKcBw219k/m/NmOyvMCCBAAJ> > in > 2025-11. > - WebKit: Shipped in Safari 17.0 > <https://webkit.org/blog/14445/webkit-features-in-safari-17-0/> in > 2023. > > *web-platform-tests*: A limited set of tests are in > https://wpt.fyi/results/jpegxl?label=master&label=experimental&aligned > <https://wpt.fyi/results/jpegxl?label=master&label=experimental&aligned&q=jpeg> > . > > -- > You received this message because you are subscribed to the Google Groups " > [email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/53b4e3e0-5eee-4768-a1ba-b069e1e85244n%40mozilla.org > <https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/53b4e3e0-5eee-4768-a1ba-b069e1e85244n%40mozilla.org?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/CAPLxc%3DV5zQJuYno-qXpPZwFocecpZt4i8b6wKAmW77%2BUnLv-VA%40mail.gmail.com.
