If what you want is a pov, and you have the .wav output from mumble, all you need to do is start the demo, and type this in the console
host_framerate 30; startmovie a_movie_
You'll get a lot of frames in your /tf/ folder. Then Vdub it together, which will take some time. I don't see why people only use this method for HQ videos, it's nice if you just want a framerate that does not stutter.