A very promising format, capable of lossless jpeg transcoding. Official website https://jpeg.org/jpegxl/ Reference software https://gitlab.com/wg1/jpeg-xl Additional info https://jpegxl.info/ https://cloudinary.com/blog/time_for_next_gen_codecs_to_dethrone_jpeg Discord with devs https://discord.gg/DqkQgDRTFu Already supported by Chrome Dev and Firefox Nightly under the flag: https://bugs.chromium.org/p/chromium/issues/detail?id=1178058 https://bugzilla.mozilla.org/show_bug.cgi?id=1539075 Others: https://github.com/novomesk/qt-jpegxl-image-plugin https://github.com/saschanaz/jxl-winthumb
In what context would MuPDF encounter JPEG XL images? PDF 2.0 doesn't support them, neither does XPS. Maybe you are thinking of EPUB or CBZ? Are there real world examples of usage? Since MuPDF isn't mainly an image viewer I'm not convinced that adding support for JPEG XL would make sense. Perhaps if it is included in PDF 2.5 or if there are other current compelling reasons..?
(In reply to Sebastian Rasmussen from comment #1) > Maybe you are thinking of EPUB or CBZ? Yeah, I am here for CBZ. JXL is still a new format and not very common, but that will change faster than we might think. Chrome and Firefox already support it as an experimental feature. Facebook will use JXL when Chrome turns it on by default. The format has many special features, one of which is the ability to losslessly transcode JPGs. This makes it possible to transcode all CBZs from JPG to JXL without losing any pixel and save up to 20% of their file size. Personally I'll get from it about 20 GiB. Some online library - I can't even imagine. And all original JPGs can be decoded back. I'm afraid that this could turn into a vicious circle. When developer A waits for developer B to add a new format, and developer B waits for the same from developer A. In the end, everyone suffers, because they're just stuck and can't use something new and improved because it's just not supported by all other programs yet.
> JXL is still a new format and not very common, but that will change faster > than we might think. Chrome and Firefox already support it as an experimental > feature. Facebook will use JXL when Chrome turns it on by default. It may become prevalent, but I think we ought wait for that to happen before we consider adding support for JPEG XL in MuPDF. Remember that when we add dependencies such as a new image decoding library we need to make it build on many platforms and we need to keep updating and/or fixing bugs in the library more or less forever. If JPEG XL was added to the e.g. PDF 2.2 specification then the situation would be very different we'd essentially be forced to support it to gain full support for one of our core file formats. So thanks for pointing to the reference library and letting us know how much support it has gained so far, but at this point we'll wait a bit longer before we add support for JPEG XL.