HighDef.org

22:11:11

Defines high definition video signals, where the luminance (Y) is sampled at 74.25 MHz and the color difference samples (R-Y,B-Y) channels are each sampled at 37.125 MHz. Note that it has become commonplace to denote HDTV Y,R-Y,B-Y also as 4:2:2. While technically incorrect, it is popularly used in a great deal of published literature.