PNG-spec
zopfli
PNG-spec | zopfli | |
---|---|---|
4 | 8 | |
42 | 3,371 | |
- | 0.3% | |
8.9 | 2.6 | |
13 days ago | 21 days ago | |
HTML | C++ | |
GNU General Public License v3.0 or later | Apache License 2.0 |
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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.
zopfli
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PSA: Use ZopfliPNG to compress your PNG assets
I'm making a 2D game with lots of PNG assets. I recently found that ZopfliPNG regularly reduces the sizes of my assets by ~3x compared to Asesprite's output. I've tried a few other PNG compression tools, but ZopfliPNG consistently outperforms the others.
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Google Chrome Is Already Preparing To Deprecate JPEG-XL (~3x smaller than JPEG, HDR, lossless, alpha, progressive, recompression, animations)
I mean something better than Google's best engineers trying to optimize LZ77's compression as much as humanly possible, while remaining compatible with the DEFLATE/zlib bitstream.
- Improving App Performance
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Losslessly Optimising Images
zopflipng typically beats pngcrus and optipng (on Linux at least) but by default it drops auxillary PNG chunks [0] which can result in browsers (and other applications) using a different color space, causing the resulting images to look more washed out than the original. To prevent this you need to explicitly pass --keepchunks=cHRM,gAMA,pHYs,iCCP,sRGB,oFFs,sTER to zopflipng.
Unfortunately it (and most other tools) don't have APNG support, keeping only the first frame.
[0] https://github.com/google/zopfli/issues/113
- Good, but slow, deflate or zlib compression library
- What am I doing wrong? ffv1 vs "h264 -crf 0"
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webP animated
I tried going with a lot of different compression algorithms, in the end a lot of iterations of Zopfli delivers the best result. With that, I got the image down to 591 kB.
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KB Club: With links to HN, Reddit, Lobsters threads for each website
I tried zopflipng [1] with the very expensive option suggested from the usage and got 2,493 bytes (original 2,740 bytes, nowhere practical as it took 3 minutes) so you don't have to sacrifice the palette, though I'm not sure if 16 or even 4 color palette will significantly alter the visual.
[1] https://github.com/google/zopfli
What are some alternatives?
qoi - The “Quite OK Image Format” for fast, lossless image compression
oxipng - Multithreaded PNG optimizer written in Rust
fpng - Super fast C++ .PNG writer/reader
guetzli - Perceptual JPEG encoder
libjxl - JPEG XL image format reference implementation
libavif - libavif - Library for encoding and decoding .avif files
spdx-spec - The SPDX specification in MarkDown and HTML formats.
optipng-bin - optipng bin-wrapper that makes it seamlessly available as a local dependency
specification - Solid Technical Reports
Zpng - Better lossless compression than PNG with a simpler algorithm
jpeg2png - silky smooth JPEG decoding
ImageOptim-CLI - Make optimisation of images part of your automated build process