Provided is a video decoding method including obtaining a bitstream including residual data about a residual block of a current block, determining a plurality of prediction directions with respect to the current block, determining a plurality of reference samples included in a neighboring region of the current block in a current image, by using the plurality of prediction directions that are determined, generating a prediction block of the current block by using the plurality of reference samples, obtaining a residual block of the current block based on the residual data about the residual block of the current block, and reconstructing the current block by using the prediction block of the current block and the residual block of the current block.