In the planning and installation of a networked video system, compression technologies play a critical part in reducing the size of files for transmission over the network and storage.
The screen of a color television tube is coated with a layer of red, green, and blue phosphor elements. Electron guns, one for each color, shoot electrons at the phosphor elements, causing them to glow briefly. Red, green, and blue colors are used, as they can be mixed together to recreate virtually any color. Each cluster of one red, one blue, and one green phosphor element is called a picture element, or pel. The intensity of the electron gun’s electron stream causes the elements to glow at various brightness levels.