I'm a PulseAudio noob, and I'm not sure if I'm even using the correct terminology. I've seen that PulseAudio can perform echo cancellation, but it needs a source and a sink to filter from, and a new source and sink. I can provide my mic and my audio-out as the source and sink, right?

Now, here's my situation: I have two video streams, say, rtmp streams, or consider two flv files, say at any given moment, stream X is the input stream that's coming from another computer's webcam+mic and stream Y is the output stream that I'm sending, (and it's coming from my computer's webcam+mic).

Question: Back to the first paragraph - here's the thing, I don't want to use my mic and my audio-out, instead, I want to use these two "input" and "output" streams as my source and sink so to speak (of course, I'll use xuggler maybe, to extract just the audio from X and Y). It may be a strange question, and I have my reasons for doing this strange this - I need to experiment and verify the results to see.