> Super cool work! I was also mucking around with codecs last week. I got some surprisingly good results from delta encoding each channel separately and then zs

> Super cool work! I was also mucking around with codecs last week. I got some surprisingly good results from delta encoding each channel separately and then zstandard compression. Dirt simple, crazy fast. My understanding is that this is one of the techniques that png uses (though not zstd) for doing it's xompression too. Along with I think some different strides down the image and some other stuff but I don't fully understand everything it tries. That's what optipng and friends play with for parameters to find the best settings for decomposing the image for compression. If you look at what jpeg and similar codecs do they nearly take a DC offset out of the image because that difference then greatly reduces the range of values you have to encode which means that you need fewer bits to do so. Combine that with range or arithmatic coding and you can get decent efficency for very little work. Then with lzw, zstd, etc. You can get lots of other patterns taken out and compressed. Lossy codecs try to take out the stuff we won't see with our eyes so that the set of values to be encoded need fewer bits and it'll also make more patterns appear that can be exploited too