Method for coding intra-prediction mode, and device for same

A picture decoding method performed by a decoding apparatus, the method comprising:

• receiving prediction related information and residual information from a bitstream;
• determining that an intra prediction is applied for a current block based on the prediction related information;
• constructing a Most Probable Modes (MPM) list including intra prediction mode candidates for the current block based on neighboring blocks of the current block;
• decoding remaining mode information indicating one of remaining intra prediction modes not included in the MPM list from the bitstream;
• deriving an intra prediction mode of the current block based on the remaining mode information;
• generating prediction samples for the current block based on the intra prediction mode;
• generating residual samples for the current block based on the residual information;
• and
• generating reconstructed samples for the current block based on the prediction samples for the current block and the residual samples for the current block,
• wherein the remaining mode information is decoded based on a truncated binary code,
• wherein a number of bits of the truncated binary code for first intra prediction modes of the remaining intra prediction modes is k, and a number of bits of the truncated binary code for second intra prediction modes excepting the first intra prediction modes among the remaining intra prediction modes is k+1,
• wherein a number of the first intra prediction modes is L, and
• wherein a following equation is applied between the k and u,
• k = floor(log2u)
• where the u represents a total number of the remaining intra prediction modes.

A picture encoding method performed by an encoding apparatus, the method comprising:

• determining that an intra prediction is applied for a current block;
• constructing a Most Probable Modes (MPM) list including intra prediction mode candidates for the current block based on neighboring blocks of the current block;
• generating remaining mode information indicating, as an intra prediction mode of the current block, one of remaining intra prediction modes not included in the MPM list;
• generating prediction samples for the current block based on the intra prediction mode of the current block;
• deriving residual samples for the current block based on the prediction samples for the current block;
• generating residual information based on the residual samples for the current block;
• and
• encoding image information including the residual information and the remaining mode information,
• wherein the remaining mode information included in the image information is encoded based on a truncated binary code,
• wherein a number of bits of the truncated binary code for first intra prediction modes of the remaining intra prediction modes is k, and a number of bits of the truncated binary code for second intra prediction modes excepting the first intra prediction modes among the remaining intra prediction modes is k+1,
• wherein a number of the first intra prediction modes is L, and
• wherein a following equation is applied between the k and u,
• k = floor(log2u)
• where the u represents a total number of the remaining intra prediction modes.

A method for transmitting data for an image, comprising:

• obtaining a bitstream of image information, wherein the bitstream is generated based on determining that an intra prediction is applied for a current block, constructing a Most Probable Modes (MPM) list including intra prediction mode candidates for the current block based on neighboring blocks of the current block, generating remaining mode information indicating, as an intra prediction mode of the current block, one of remaining intra prediction modes not included in the MPM list, generating prediction samples for the current block based on the intra prediction mode of the current block, deriving residual samples for the current block based on the prediction samples for the current block, generating residual information based on the residual samples for the current block, and encoding image information including the residual information and the remaining mode information;
• and
• transmitting the data comprising the bitstream of the image information including the residual information and the remaining mode information,
• wherein the remaining mode information included in the image information is encoded based on a truncated binary code,
• wherein a number of bits of the truncated binary code for first intra prediction modes of the remaining intra prediction modes is k, and a number of bits of the truncated binary code for second intra prediction modes excepting the first intra prediction modes among the remaining intra prediction modes is k+1,
• wherein a number of the first intra prediction modes is L, and
• wherein a following equation is applied between the k and u,
• k = floor(log2u)
• where the u represents a total number of the remaining intra prediction modes.