Device and method for controlling a video signal gain

Abstract

A device and a method for controlling a video signal in a video display device controls a magnitude of an RGB video signal by controlling RGB gain values based on RGB count values controlled through external key inputs. The method comprises the steps of: reading the RGB gain values and the RGB count values stored in a storage part; receiving inputs of an RGB color selection key; receiving inputs of a level control key; reading count values of colors selected by the color selection key inputs, and controlling the read count values based on the level control key inputs; calculating difference values between the count values of colors controlled and the count values of the other colors read in the initial reading step by comparing the count values controlled based on the level control by inputs with the count value read in the first step, and controlling the RGB gain values according to the calculated difference values; and updating the storage part with the count values and the gain values controlled in the two preceding steps. As a result, the brightness is not greatly increased or decreased and constant color coordinates are maintained when the RGB gains are controlled by controlling the RGB gain values according to the difference values calculated by comparing the color count values controlled by a user with the other color count values not controlled.