A video coding or decoding method in which luminance and chrominance samples in a 4:4:4 format or a 4:2:2 format are predicted from other respective samples according to a prediction direction associated with blocks of samples to be predicted; comprises detecting a prediction direction in respect of a current block to be predicted; generating a predicted block of chrominance samples according to other chrominance samples defined by the prediction direction; if the detected prediction direction is substantially vertical, filtering the left column of samples in the predicted block of chrominance samples, or if the detected prediction direction is substantially horizontal, filtering the top row of samples in the predicted block of chrominance samples; and encoding a difference between the filtered predicted chrominance block and the actual chrominance block or applying a decoded difference to the filtered predicted chrominance block so as to encode or decode the block respectively.