a) A commonly used term for a component digital video format.

The details of the format are specified in the CCIR-601 standard document.

The numerals 4:2:2 denote the ratio of the sampling frequencies of the single luminance channel to the two color difference channels. For every four luminance samples, there are two samples of each color difference channel.

b) ITU-R BT.601 digital component waveform sampling standard where the luminance signal is sampled at the rate of 13.5 MHz, and each of the color difference signals, (Cr and Cb) are sampled at the rate of 6.25 MHz each. This results in four samples of the luminance signal for each two samples of the color difference signals. See ITU-R BT.601-2.