motion detection from VDR output

[Sean]

I have a set of Swan cameras recording video from around the premises on a schedule. The recording goes to a VDR attached to the other end of their cables, etc. The VDR records onto a built-in hard drive, but I can also dub the recorded data to a DVD-Ram if need be. Actually, however, if I want to transfer the data to a computer disk, it is easier for me to make use of a USB dongle device for video capture, which I can connect from the RCA video jacks of the VDR directly to a USB port on the PC. On this PC I make use of both Linux and Windows.

I would like to find a way to filter the video from the recorded data on the PC in order to detect motion in the video. Ideally, I would like to be able to feed the data through a program which would seek the points where motion was detected and somehow convey to me at what points such motion occurred. It would be great if I could do this somehow or another with the VLC Media Player program, since I already have it installed. However, I have found very little material discussing how to accomplish this. If someone could point me in the right direction, I would appreciate it immensely--if not with VLC, then with another program.