What I've always wondered - are there any screen recording utilities where the frame grabber can be invoked by a manual trigger signal rather than a timer?
If so, you could set orbiter to a fixed time step size, say 1/30s, send a trigger to the frame grabber at each frame, and get a perfect 30fps video independent of how fast your computer actually is. No more jerky videos.
I'm doing my own (short) videos by writing out a jpg screenshot at each frame, and then converting them to video with avidemux. But this requires a huge intermediate amount of disk space, and writing out the jpgs is very slow, so it can't be used interactively - but it still works for pre-recorded flights.