In C, I was using ffmpeg's functions directly instead of their CLI. I was manually decoding packets, frames and so on. Having to do all of this, I quickly became familiar with how ffmpeg works (and got able to read their source code) ; but this level of control was unneeded to create a HLS multi-variant stream. I made more sense to simply call ffmpeg via it's CLI interface and use a higher level language to manage states.
I then moved to rust, mostly because I was curious about the language. When I decided to use the original's video keyframes I needed to rewrite everything anyway, so I decided to change language at this time. The CLI interface did not change but using golang made state management easier since it has great tooling for (goroutines, concurrent maps, channels...). Rust lacks those tools, and it was hard to handle mutexes and so on.
I then moved to rust, mostly because I was curious about the language. When I decided to use the original's video keyframes I needed to rewrite everything anyway, so I decided to change language at this time. The CLI interface did not change but using golang made state management easier since it has great tooling for (goroutines, concurrent maps, channels...). Rust lacks those tools, and it was hard to handle mutexes and so on.