https://github.com/TheRealOrange/icer_compression is pretty neat – a mostly complete implementation of ICER, a wavelet-based, error-resilient image compression format designed by NASA 20+ years ago for Spirit and Opportunity.
It’s pretty old-fashioned now. The vanilla DWT, the Tudor-era entropy coder – with only admiration for what it was in 2003, no one would propose a new format like ICER today. But it’s interesting in itself and as a what-if. (What if JPEG 2000 were designed for normal people, basically.)
I was just saying to a friend that JPEG 2000 never succeeded in supplanting JPEG outside a few high-end niches (mapping, archives, medical imaging) due to a scope-crept, complex, IP-unclear, and generally unappealing-to-nonspecialist-developers design, but I think there’s an alternate history not too far away in the multiverse where someone adapted ICER into an OS and browser-supported JPEG replacement in, like, 2005.