Encoding method and apparatus therefor, and decoding method and apparatus therefor

A video decoding apparatus comprising:

• a memory storing at least one instruction for performing video decoding;
• and
• a processor configured to execute the at least one instruction,
• wherein the processor is further configured to, in response to the at least one instruction,
• obtain intra prediction mode information indicating an intra prediction mode of a current block,
• determine an intra prediction direction indicated by the intra prediction mode information, according to a shape of the current block,
• predict the current block by intra predicting the current block in the intra prediction direction, and
• reconstruct the current block, according to a prediction result with respect to the current block, and
• wherein, when the current block has a square shape, the intra prediction mode of the current block is determined from first intra prediction direction candidates determined according to the square shape,
• wherein, when the current block has a non-square shape, the intra prediction direction of the current block is determined from second intra prediction direction candidates determined according to a width and a height of the non-square current block, and
• wherein the first intra prediction direction candidates and the second intra prediction direction candidates are determined from an intra prediction direction candidate group comprising a plurality of prediction directions.

A video encoding method comprising:

• determining an intra prediction direction to be used in prediction of a current block, from among a plurality of intra prediction directions;
• determining intra prediction mode information indicating an intra prediction mode of the current block, according to a shape and the intra prediction direction of the current block;
• and
• outputting a bitstream comprising intra prediction mode information,
• wherein the determining of the intra prediction mode information of the current block comprises,
• when the current block has a square shape, determining the intra prediction mode information from first intra prediction direction candidates determined according to the square shape, and
• when the current block has a non-square shape, determining the intra prediction mode information of the current block from second intra prediction direction candidates determined according to a width and a height of the non-square current block, and
• wherein the first intra prediction direction candidates and the second intra prediction direction candidates are determined from an intra prediction direction candidate group comprising a plurality of prediction directions.