EN: 4:2:2


Standard definition video signals with luminance (Y) sampled at 13.5 MHz and color difference (R-Y, B-Y) channels each sampled at 6.75 MHz. Now in common usage describing both high definition and standard definition systems with the ratio between luminance and chrominance samples at 2:1-two sets of color difference samples (R-Y, B-Y) for every four luminance samples (Y).
Canon USA