Different color spaces are useful for different purposes and transformations translate data from one color space to another. The color encoding systems used for videos are derived from the RGB color space. RGB is an additive space that uses combinations of Red, Green, and Blue primaries. The RGB system is transformed to other systems that allow video-encoding techniques to exploit the characteristics of human color perception. Brightness and color information are treated differently by the human visual system.
Humans are more sensitive to changes in brightness than changes in color.
NTSC format is used in the Americas and Japan. PAL format is used in Western Europe and Australia. Analog video is digitized so that a computer may manipulate it. Each frame of video becomes a two dimensional array of pixels. A complete color image is composed of three image frames, one for each color component.