| 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)] | 3 Claims |

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1. An image decoding method performed by a decoding apparatus, the image decoding method comprising:
deriving a refined L0 motion vector by applying decoder-side motion vector refinement (DMVR) based on an L0 motion vector of a current block and a refined L1 motion vector by applying the DMVR based on an 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 motion vector is related to an L0 reference picture and the L1 motion vector is related to an L1 reference picture,
wherein the L0 prediction samples are derived based on the L0 reference picture and the refined L0 motion vector, and the L1 prediction samples are derived based on the L1 reference picture and the refined L1 motion vector,
wherein the deriving of the prediction samples comprises deriving bi-directional optical flow (BDOF) flag information related to indicating whether to apply BDOF, 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,
wherein, based on a case where the first POC difference and the second POC difference are the same, a value of the BDOF flag information is set to a value related to applying the BDOF to the current block, and
wherein it is determined that the DMVR is applied based on a case that a merge mode is applied to the current block.
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