I anticipate some much more savvy than myself saying this wrapper is unnecessary as you can do all of this “easily” with ffmpeg. I welcome tools like this that have a more common user in mind, evidenced immediately in the beginning of the README with common use cases.
Ffmpegs documentation on the other hand forces me to feel as though it’s normal to assume knowledge about a point in a video and what it means if my encoders are different from input to output.