need advice: saving some portions of a video stream

[Ram Bhamidipaty]

Hi,

I am looking for advice on how to save small portions of a video stream.


I have a basic security cam application - and I want to save some 
portions of

of the output stream. I can currently process the input video stream and 
send it

to a motion detection processor, and I can save the full video stream to 
disk as

a Transport Stream.


Instead - what I would like to do is only save the video when motion is 
detected,

something like one minute before and three minutes after motion is 
detected.


I was thinking about modifying the mpegtsmux or maybe the filesing 
plugin.  Or

perhaps there is some better way. Suggestions are welcome.


Thank you for any input.

-Ram