That'd be a great solution, I'm using ffmpeg in my personal media server app to generate thumbnails and transcode media on the fly and I was wondering that too.

There are also a few things that I had to patch on top of ffmpeg (for example it doesn't do well with generating singular HLS packets on demand). Would be nice to have a pluggable architecture that can link multiple things together like that.

Might implement this myself if I end up having the time for that.