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Are there formats that try to do more of a 2D compression? With png horizontal lines compress way better than vertical lines. Something like what JBIG2 does but
by yread 4y ago
Are there formats that try to do more of a 2D compression? With png horizontal lines compress way better than vertical lines. Something like what JBIG2 does but without the focus on letters
- pavlov 4y agoMost image compression formats work in pixel blocks instead of scanlines. For example JPEG uses a 8x8 block size. This way rotating the image doesn't affect compression performance (unlike PNG).
- Retr0id 4y agoJPEG-XL's lossless mode has something called the "squeeze transform" which operates over the image data in 2D. It's a variation of the Haar Transform, which works on a similar principle as DCT https://en.wikipedia.org/wiki/Haar_wavelet#Haar_transform https://en.wikipedia.org/wiki/Haar_wavelet#Haar_transform It also has "meta-adaptive filters", which act similarly to PNG's filters except you get to encode a custom decision-tree that defines how pixels are filtered, as a function of their neighboring pixels