CPC H04N 19/137 (2014.11) [H04N 19/105 (2014.11); H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/46 (2014.11)] | 14 Claims |
1. An image decoding method performed by a decoding apparatus, the image decoding method comprising:
deriving an L0 motion vector and an L1 motion vector of a current block;
deriving a refined L0 motion vector and a refined L1 motion vector by applying decoder-side motion vector refinement (DMVR) based on the L0 motion vector and the L1 motion vector of the current block;
deriving prediction samples for the current block based on L0 prediction samples derived based on the refined L0 motion vector and L1 prediction samples derived based on the refined L1 motion vector; and
generating reconstructed samples for the current block based on the prediction samples,
wherein the L0 prediction samples are derived based on an L0 reference picture and the refined L0 motion vector, and the L1 prediction samples are derived based on an L1 reference picture and the refined L1 motion vector,
wherein the prediction samples for the current block are derived by applying bi-directional optical flow (BDOF) to the current block based on BDOF flag information indicating whether to apply BDOF to the current block,
wherein the BDOF flag information is derived based on whether a first picture order count (POC) difference between a current picture and the L0 reference picture and a second POC difference between the current picture and the L1 reference picture are the same, and whether a value of bi-prediction weight index information of the current block is equal to 0, and
wherein based on a case where the first POC difference and the second POC difference are the same, and the value of the bi-prediction weight index information of the current block is equal to 0, a value of the BDOF flag information is set to a value related to applying the BDOF to the current block.
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