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What’s the best lossless image format?

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Re: What’s the best lossless image format?

#71
post #38

Earlier quoted context omitted.

Everything about JPEG XL sounds great, except that it takes about 34 times longer to encode an image compared to PNG. Edit: Apparently there's an experimental faster version: https://github.com/libjxl/libjxl/tree/main/experimental/fast...

Depends, are you optimizing the PNG? Because cjxl is a hell of a lot faster for a much smaller file than zopflipng.

zopflipng is a very aggressive form of optimization.

Re: What’s the best lossless image format?

#72
post #69

If you want something that is going to be around for awhile and has a LOT of features you probably do not need then you are going to want to go probably with a .DPX or .EXR which are the standard for the VFX industry as well as film in general. On the consumer side I guess adobe .DNG might not be bad either or for maximum compatibility but then maybe a Tiff. For video I personally like Cineform but both ProRes and DN…

How do EXR and JXL compare to each other, feature-wise?

I have never used JXL honestly - no job I have had it was ever even considered. Given the Jpeg in the name I doubt any pro studio would consider it given the other options do everything needed. DPX is basically the older standard for film and EXR is the newer one.

edit: Just looked at the specs and JpegXL is definitely marketed at least more as a web end viewing file type. It does higher color depths (up to 16 bit) which is pretty good but will not do 32 bit like EXR. Given that EXR is so widely used I would likely not consider anything else.

Re: What’s the best lossless image format?

#73

Earlier quoted context omitted.

Why is encoding speed irrelevant? I'm currently in the process of scanning and archiving lots of photographs as high-resolution 16-bit PNG's and encoding speed is definitely a significant influence on how long this process takes.

You missed the "almost". The vast majority of use-cases and users barely care about encoding performance. Your use is in the tiny minority. That isn't to say that you don't have a use-case, just that because of how rarely encoding speed matters, it truly is "almost irrelevant" for 99.99% of users 99.99% of the time. -------------- It definitely would be nice if JPEG-XL also had good encoding performance, though. Ther…

It’s common enough to create an image on the fly and send it to a single user to be viewed once.

Re: What’s the best lossless image format?

#74

JPEG XL is the standard to beat them all. Like how Opus became the definitive codec for lossy compression for the web. JPEG XL covers nearly every use case for images, even replacing GIFs with it's animation support. Existing JPEGs can also be re-encoded losslessly into JPEG XL format/data structure and get significant file size savings. This backwards compatiability is very important in transitioning to web to JPEG…

Unless nobody adopts it?

EXR seems like it does all of the high end pro features of JpegXL and more (including 32 bit color). JPEGXL can do some odd stuff like animated gif type images but that seems more like a web end user feature than something professionals would care about. I can see it replacing Jpeg / GIF but I don't see this becoming an industry standard anytime soon.

Re: What’s the best lossless image format?

#75
post #38

JPEG XL is the standard to beat them all. Like how Opus became the definitive codec for lossy compression for the web. JPEG XL covers nearly every use case for images, even replacing GIFs with it's animation support. Existing JPEGs can also be re-encoded losslessly into JPEG XL format/data structure and get significant file size savings. This backwards compatiability is very important in transitioning to web to JPEG…

Everything about JPEG XL sounds great, except that it takes about 34 times longer to encode an image compared to PNG. Edit: Apparently there's an experimental faster version: https://github.com/libjxl/libjxl/tree/main/experimental/fast...

If it takes that much longer to encode then I am guessing it takes a lot longer to decode as well which I am going to guess makes it completely out for image sequences, film archiving, VFX work, high end photography, etc etc.

Re: What’s the best lossless image format?

#76

Earlier quoted context omitted.

How many megabytes per second is your scanner feeding you? I'm very surprised that encoding a PNG is slower than scanning.

It's not slower than scanning, but I still spend a significant amount of time waiting for the maximum compression PNG encoding to complete.

If it's not encoding in the background so it can be done within a second or so of the data finishing, then it's just programmed wrong, it's not an encoding speed problem.

Re: What’s the best lossless image format?

#77

Earlier quoted context omitted.

Quite, and encoding speed, which is included, seems almost irrelevant

Why is encoding speed irrelevant? I'm currently in the process of scanning and archiving lots of photographs as high-resolution 16-bit PNG's and encoding speed is definitely a significant influence on how long this process takes.

Can I ask why you chose PNG for your archive format?

Re: What’s the best lossless image format?

#78
post #18
post #10

> What is the best lossless image format? For which application? Otherwise you can only say " depends ". Tiff is good if you want to save data fast to disk in Blender. EXR is great if you want 32bit color depth, etc.

> Tiff is good Mind that TIFF is only a container format that can contain any arbitrary codec you like; it can be uncompressed pixels, RLE compressed, it can be a PNG, a JPEG XL, even lossy JPEG or WebP if you'd like. Saying your image format is TIFF is roughly as useful and conveys as much information as saying your video format is MKV.

Usually with TIFF people mean uncompressed.

Re: What’s the best lossless image format?

#79

Earlier quoted context omitted.

Quite, and encoding speed, which is included, seems almost irrelevant

Why is encoding speed irrelevant? I'm currently in the process of scanning and archiving lots of photographs as high-resolution 16-bit PNG's and encoding speed is definitely a significant influence on how long this process takes.

Not a bad choice - all that really matters in those cases anyways is what your scanner is capable of

Re: What’s the best lossless image format?

#80

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 faithfull…

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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