This is the first motion detection release.
Uncomment the -DMOTION in the Makefile, and when in loop capture, videodog will only save changing frames.
The algorithm is explained into motion.c, and the approach is very simple.
The entry point is inside video.c file, grab_loop function. Its very beta software, but have been working ok for me. 
There are two functions:

detect_motion - which only detects and returns an average changed pixel number, but keeps image as it were before analysis

subtract_motion - which does the same, but returns a modified image, containing only the diff'ed pixels.


