NTA but if the assumption is that the reader has only a basic understanding of C programming and wants to contribute to a video codec there is a lot of ground that needs to be covered just to get to how the cooley/tukey algorithm works and even that's just the basic fundamentals.

I read the repo more as "go through this if you want to have a greater understanding of how things work on a lower level inside your computer". In other words, presumably it's not only intended for people who want to contribute to a video codec/other parts of ffmpeg. But I'm also NTA, so could be wrong.