V4L capture program supporting motion detection

 Motion is a program that monitors the video signal from
 one or more cameras and is able to detect if a significant
 part of the picture has changed. Or in other words, it can
 detect motion.
 .
 Motion is a command line based tool. It has no graphical
 user interface. Everything is setup either via the
 command line or via configuration files.
 .
 The output from motion can be:
    - jpg/ppm image files
    - mpeg/mp4/swf/flv/mov/ogg video sequences
 .
 Also, motion has its own minimalistic web server. Thus,
 you can access the webcam output from motion via a browser.