Is there a tool that converts Doom demos to videos?

I'd like to upload some demos to YouTube, rather than just send them as LMPs to people. Is there any tool that plays vanilla-compatible LMPs and outputs everything to a movie file? Preferably without rendering to the screen. Just a command-line tool that runs the Doom engine on the demo and writes to a movie.

I know that general screen-capturing programs exist, but they're neither foolproof nor portable, and tend to be rather heavy instead. A Doom port that simply outputs its audio/video to a stream would be ideal.

prboom+ can do this. There are instructions in its usage file for how to set it up. Idk about preventing it from rendering to a display, but there might be a way to do that.