A decoder includes a parser, an intra predictor, and an inter predictor. The parser parses a bit stream to extract header information and first through third data information, to determine a prediction mode for blocks in a current frame based on the header information, and to selectively output the first and second data information based on the prediction mode. The intra predictor generates a predicted value of a pixel of a current block based on a pixel value of a first reference block in the current frame based on the first data information. The inter predictor predicts a second reference block from a reference frame based on the second data information, converts a pixel value of the second reference block, and generates a predicted value of the pixel of the current block based on a converted pixel value.