Image coding method and apparatus based on intra prediction using MPM list

An image encoding method performed by an encoding apparatus, the method comprising:

• deriving an intra prediction mode for a current block;
• generating MPM flag information, planar flag information and MPM index information based on the derived intra prediction mode, wherein the MPM flag information is related to whether the intra prediction mode for the current block is derived based on most probable mode (MPM) candidates for the current block,
• the planar flag information is related to whether to determine the intra prediction mode for the current block as a planar mode, and the MPM index information related to one of 5 MPM candidates other than the planar mode among the MPM candidates for the current block,
• encoding image information comprising the MPM flag information, the planar flag information and the MPM index information,
• wherein the MPM flag information is configured in a coding unit syntax for the current block,
• wherein based on a value of the MPM flag information representing that the intra prediction mode for the current block is derived based on the MPM candidates, the planar flag information is configured in the coding unit syntax, and
• wherein based on a value of the planar flag information representing that the intra prediction mode for the current block is not as the planar mode, the MPM index information is configured in the coding unit syntax.

A non-transitory computer readable storage medium comprising:

• encoded information which causes a decoding apparatus to perform an image decoding method,
• wherein the image decoding method comprises
• obtaining intra prediction information comprising most probable mode (MPM) flag information related to whether to derive an intra prediction mode for a current block based on most probable mode (MPM) candidates for the current block, planar flag information representing whether to determine the intra prediction mode for the current block as a planar mode, and MPM index information related to one of 5 MPM candidates other than the planar mode among the MPM candidates for the current block;
• deriving the intra prediction mode for the current block based on at least one of a value of the MPM flag information, a value of the planar flag information or a value the MPM index information;
• deriving a predicted block for the current block based on the intra prediction mode for the current block;
• and
• generating a reconstructed picture based on the predicted block, and
• wherein the MPM flag information is configured in a coding unit syntax for the current block,
• wherein based on the value of the MPM flag information representing that the intra prediction mode for the current block is derived based on the MPM candidates, the planar flag information is configured in the coding unit syntax, and
• wherein based on the value of the planar flag information representing that the intra prediction mode for the current block is not as the planar mode, the MPM index information is configured in the coding unit syntax.