Not really an abstraction for ffmpeg, but a bit of PDL that can interface with it: PDL::IO::Pic. I can envision (ha!) additional functionality for the rmpeg function that could interface to a stream (obviously relying largely on ffmpeg capability). Today, that's a synchronous read rather than a stream.

What do people think would some sample (maybe pseudo-)code look like that would solve this? I anticipate a write-stream as well, but don't want to bias people's thinking.