Video Capture from an X11 Window?

Dandre asks: "I'm trying to capture video from an X11 window containing a java display of my research into an MPEG. The only 'solution' I was able to find was to use x11rec, which stores an animated gif from the window. I then can presumably use various tools (mpeg2encode & gimp) to split this into separate images then bind it together again into an MPEG. I would have thought there was a simple tool to just capture directly into MPEG from the given display. Does anyone have any suggestions?"