Delivers the best quality analogue video image as it contains all the origional components of the image as opposed to the compression used in composite video.
The two commonly used systems are RGB and Y,R-Y,B-Y.
RGB is simply the red,green and blue elements of the picture having one wire each. Y,R-Y,B-Y is slightly different in that Y carries a black and white picture, R-Y the red element and B-Y the blue element. Green is extracted by taking the red and blue elements from Y and whatever is left is green.
Comonent Video RCA Sockets