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Comment by bumper_crop | Hacker News Reader

The best lossless format is the one you can decode back to the original image. When evaluating them, there is an implicit assumption that the decode step will happen a short time later, but that's not always true. Will there be JPEG XL decoders commonly available in 40 years? Will the code even compile then? As a thought experiment, try to find the lossless encodings from 40 years ago and see if they can be faithfully reproduced. (or even 20 years ago, remember JPEG2000?)

Framing best in terms of file size or encoding speed is a really use-specific framing, and not ideal for preservation.

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Your concern is valid but misplaced, there is a reason that we have standards after all. The Library of Congress maintains file format evaluations for the purpose of preservation, and there is an (pretty favorable) entry for JPEG XL [1] as well. Not yet in public, but I'm also working on the very first reimplementation of JPEG XL from scratch and reporting any spec bugs from ISO/IEC 18181 (there are plenty!) and I expect there would be more implementations in the future.

[1] https://www.loc.gov/preservation/digital/formats/fdd/fdd0005...

> or even 20 years ago, remember JPEG2000?

Open Source JPEG2000 libraries:

- Grok, last commit 9 hours ago: https://github.com/GrokImageCompression/grok

- JasPer, last commit 5 days ago: https://github.com/jasper-software/jasper

- OpenJPEG, last commit 8 days ago: https://github.com/uclouvain/openjpeg

I didn't try them, but I think you can probably still read your 20 year old JPEG2000 files today without too much problems.

This seems excessively handwringing about code rot. TIFF was introduced 35 years ago and still well supported. JPEG2000 didn't become super widespread, but is still used in many places. Smart passports encode your passport photo in JPEG2000 for example.

Another example is in radiology. Many thousands of medical images are created and stored in lossless JPEG2000 every day with entire ecosystems of software to store and move them.

Also in digital cinemas films are JPEG2000 sequences.

Huh?

Exactly what they said. Movies in cinemas with digital projectors are distributed as sequences of JPEG 2000 images: https://en.wikipedia.org/wiki/Digital_Cinema_Package

The question isn’t whether any format from 35 years ago is still feasible to decode. The question is whether every format from back then is.

This is a good point - and also not just is it POSSIBLE to do - but is it easy?

Say you archive hours and hours and hours of footage and photographs in JPEG XL and then in 5 years the industry moves on to something completely different (maybe even worse in terms of specs) like the beta vs VHS thing. In 20 years it will surely be possible to decode those JPEG XL files but if you just want to send one to a friend and they have to jump through hoops to view it then it becomes a pretty big pain in the butt.

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