This C implementation of the QOI (Quite OK Image) foramt is implemented according to the specification and is heavily influenced by the original C implementation on GitHub.
Some optimizations and better programming practices make the code somewhat more readable. Overall, it was a fun experiment in reading and implementing a specification and is definitely something that could be easily be adapted for a classroom or workshop. Specifically, everything inside the for-loops in the qoi_decode() and qoi_encode() functions inside qoi.c file is fair game for anyone with basic programming experience.
I really appreciate this codec because of it's simplicity and that it minimally uses any RAM. In fact, the implementation mostly uses a hash table, a run length, the current pixel, and the previous pixel.