PNG-spec
Zpng
PNG-spec | Zpng | |
---|---|---|
4 | 4 | |
42 | 254 | |
- | - | |
8.9 | 10.0 | |
13 days ago | almost 6 years ago | |
HTML | C | |
GNU General Public License v3.0 or later | BSD 3-clause "New" or "Revised" License |
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PNG-spec
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Hello, PNG!
Pull requests welcome. :D
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Are IDAT chunks in PNG encoded individually?
There are multiple github issues on the subject where we work on future editions of the PNG spec. (3rd Edition coming soon!)
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Google Chrome Is Already Preparing To Deprecate JPEG-XL (~3x smaller than JPEG, HDR, lossless, alpha, progressive, recompression, animations)
Especially enticing as the PNG file format does allow for additional compression/filter methods and new ones could be added to a PNG 2.0 standard. A small wishlist discussion about that at the W3C's PNG specification Github.
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QOI – The “Quite OK Image Format” for fast, lossless image compression
> But its not like any reader ever supports it fully, hell most readers dont support showing the other images in a png file.
Do you mean APNG? In all fairness, that is not even in the specification although there is discussion to add it. https://github.com/w3c/PNG-spec/issues/26
The one that was specified was MNG but it was a different format and practically no one used it since it was not parsable as a PNG.
Zpng
- Zpng: Better lossless compression than PNG with a simpler algorithm
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Quite OK Image is now my favorite asset format
> You'd probably get even better results by using PNG's filters instead of QOI
Did anybody ever try this? It would be quite interesting and does not seem too difficult.
The only thing I could find is https://github.com/catid/Zpng which does not use the normal PNG filtering.
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Google Chrome Is Already Preparing To Deprecate JPEG-XL (~3x smaller than JPEG, HDR, lossless, alpha, progressive, recompression, animations)
Also, Chris Taylor published an experimental PNG library with Zstd hardwired in.
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QOI: Lossless Image Compression in O(n) Time
- I feel like the benchmark suite is lacking. For better overview you probably should include libpng results with max compression level and lowest compression level. Lossless modes of AVIF and WEBP would be nice. (also could throw similar project to yours like https://github.com/catid/Zpng) Not saying the benchmark is bad, but IMHO doesn't paint the full picture. From quick test I got significantly better compression on libpng, ofc in expense of time, but you didn't optimize it for speed either. So we have some results, but they are not really representative imho.
What are some alternatives?
qoi - The “Quite OK Image Format” for fast, lossless image compression
fpng - Super fast C++ .PNG writer/reader
ZLib - A massively spiffy yet delicately unobtrusive compression library.
zopfli - Zopfli Compression Algorithm is a compression library programmed in C to perform very good, but slow, deflate or zlib compression.
qoi - Pure Go encoder/decoder of the QOI image format
libjxl - JPEG XL image format reference implementation
spdx-spec - The SPDX specification in MarkDown and HTML formats.
qoi - A rust implementation of the “Quite OK Image” format for fast, lossless image compression
specification - Solid Technical Reports
rawloader - rust library to extract the raw data and some metadata from digital camera images