The present disclosure relates to a method and an apparatus for encoding/decoding a color image or video. The video encoding apparatus encodes a luminance component block for a current block of an image, performs a selection of a color format among a plurality of color formats to encode a chrominance component block for the current block of the image according to the color format upon selection, and generates and outputs a bitstream including the encoded luminance component block, the encoded chrominance component block, and information on the selected color format. The disclosure enables an improvement in compression performance by allowing encoding and decoding one video component image in various color formats.