chrominance

Chrominance (chroma or C for short) is the signal used in video systems to convey the color information of the picture, separately from the accompanying luma signal (or Y for short). Chrominance is usually represented as two color-difference components: U = B' - Y' (blue - luma) and V = R' - Y' (red - luma). Each of these difference components may have scale factors and offsets applied to it, as specified by the applicable video standard.