4:2:0

4:2:0 - A sampling system used to digitize the luminance and color difference components (Y, R-Y, B-Y) of a video signal. It decreases the overall data by 25 percent against 4:2:2 sampling and the color information has a reasonably even resolution in both the vertical and horizontal directions. 4:2:0 is widely used in MPEG-2 coding meaning that the broadcast and DVD digital video seen at home is usually sampled this way.