Intra prediction-based video coding method and device using MPM list
A video decoding method according to the present document comprises the steps of: configuring an MPM list by deriving candidate intra prediction modes on the basis of a first neighboring block located on the left side and a second neighboring block located on the upper side with respect to the current block; deriving an intra prediction mode for the current block on the basis of the MPM list; generating prediction samples for the current block on the basis of the intra prediction mode; and generating a reconstructed picture for the current block on the basis of the prediction samples, wherein a first intra prediction mode of the first neighboring block and a second intra prediction mode of the second neighboring block are the same, wherein the candidate intra prediction modes including a DC mode are derived on the basis of a case where both the first intra prediction mode and the second intra prediction mode are the DC mode.
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining intra prediction mode information and residual information from a bitstream;
deriving candidate intra prediction modes based on a first neighboring block adjacent to a left of a current block and a second neighboring block adjacent to an upper of the current block;
constructing a most probable mode (MPM) list based on the candidate intra prediction modes;
deriving an intra prediction mode for the current block based on the MPM list and the intra prediction mode information;
generate prediction samples for the current block based on the intra prediction mode;
generate residual samples for the current block based on the residual information; and
generating reconstructed samples based on the prediction samples and the residual samples,
wherein based on a case where a first intra prediction mode of the first neighboring block and a second intra prediction mode of the second neighboring block are the same and both the first intra prediction mode and the second intra prediction mode are the DC mode, the candidate intra prediction modes in the MPM list include a DC mode and directional intra prediction modes,
wherein the directional intra prediction modes are added after the DC mode in the MPM list, and the directional intra prediction modes include an intra prediction mode 50 , an intra prediction mode 18 , an intra prediction mode 46 , and an intra prediction mode 54 , and
wherein the DC mode is related to a first index of the MPM list, the intra prediction mode 50 is related to a second index of the MPM list, the intra prediction mode 18 is related to a third index of the MPM list, the intra prediction mode 46 is related to a fourth index of the MPM list, and the intra prediction mode 54 is related to a fifth index of the MPM list.
2. An image encoding method performed by an encoding apparatus, the method comprising:
deriving candidate intra prediction modes based on a first neighboring block adjacent to a left of a current block and a second neighboring block adjacent to an upper of the current block;
constructing a most probable mode (MPM) list based on the candidate intra prediction modes;
deriving an intra prediction mode of the current block based on the MPM list;
generate prediction samples for the current block based on the intra prediction mode;
generate intra prediction mode information based on the intra prediction mode;
generate residual samples for the current block based on the prediction samples;
generate residual information based on the residual samples; and
encode image information including the intra prediction mode information and the residual information,
wherein based on a case where a first intra prediction mode of the first neighboring block and a second intra prediction mode of the second neighboring block are the same and both the first intra prediction mode and the second intra prediction mode are the DC mode, the candidate intra prediction modes in the MPM list include a DC mode and directional intra prediction modes,
wherein the directional intra prediction modes are added after the DC mode in the MPM list, and the directional intra prediction modes include an intra prediction mode 50 , an intra prediction mode 18 , an intra prediction mode 46 , and an intra prediction mode 54 , and
wherein the DC mode is related to a first index of the MPM list, the intra prediction mode 50 is related to a second index of the MPM list, the intra prediction mode 18 is related to a third index of the MPM list, the intra prediction mode 46 is related to a fourth index of the MPM list, and the intra prediction mode 54 is related to a fifth index of the MPM list.
3. A method for transmitting data for image information comprising:
obtaining a bitstream of image information, wherein the bitstream is generated based on deriving candidate intra prediction modes based on a first neighboring block adjacent to a left of a current block and a second neighboring block adjacent to an upper of the current block, constructing a most probable mode (MPM) list based on the candidate intra prediction modes, deriving an intra prediction mode of the current block based on the MPM list, generate prediction samples for the current block based on the intra prediction mode, generate intra prediction mode information based on the intra prediction mode, generate residual samples for the current block based on the prediction samples, generate residual information based on the residual samples, encode image information including the intra prediction mode information and the residual information; and
transmitting the data comprising the bitstream of the image information,
wherein based on a case where a first intra prediction mode of the first neighboring block and a second intra prediction mode of the second neighboring block are the same and both the first intra prediction mode and the second intra prediction mode are the DC mode, the candidate intra prediction modes in the MPM list include a DC mode and directional intra prediction modes,
wherein the directional intra prediction modes are added after the DC mode in the MPM list, and the directional intra prediction modes include an intra prediction mode 50 , an intra prediction mode 18 , an intra prediction mode 46 , and an intra prediction mode 54 , and
wherein the DC mode is related to a first index of the MPM list, the intra prediction mode 50 is related to a second index of the MPM list, the intra prediction mode 18 is related to a third index of the MPM list, the intra prediction mode 46 is related to a fourth index of the MPM list, and the intra prediction mode 54 is related to a fifth index of the MPM list.