This is what I have asked for a couple of years ago as well with the answer "not a motion topic". I regard this to be a valid answer since it's vital for motion to be a basic middleware rather than a complete solution. I recommend to look at mjpg-streamer to do those things behind the loopback devices (which has the smart advantage to get also the outputs / settings from motion in to the stream as well).
-- AxelAmthor - 22 Oct 2009