This is a proof of concept for simultaneous upload, processing and download of a file, using node.js streams. The basic premise is that you upload a movie file, it gets processed by FFMpeg and turned into a .mp3 with the movie's audio, and that gets sent back to the user as a .mp3 file. I encourage you to look through the server.js source code.
Note that this is just a proof of concept at this point; it only allows one user at the same time, and it may hog all the server's CPU/memory/whatever.
In order to use this, you need to have a ffmpeg binary installed with .mp3 support.
