FIELD: image encoding.
SUBSTANCE: invention is related to image encoding, and more particularly to a method and equipment for performing mutual prediction based on decoder-side motion vector refinement (DMVR) and bi-directional optical flow (BDOF). An image decoding method is provided in which DMVR is applied to extract detailed L0 and L1 motion vectors based on the L0 and L1 motion vectors of the current block; prediction samples of the current block are derived based on L0 prediction samples derived based on the detailed L0 motion vector and L1 prediction samples derived based on the detailed L1 motion vector; and reconstruction samples of the current block are generated based on the prediction samples, wherein the L0 prediction samples are derived based on the L0 reference frame and the detailed L0 motion vector, the L1 prediction samples are derived based on the L1 reference frame and the detailed L1 motion vector, and in the step for extracting predictive samples, whether or not to apply the BDOF extraction process is determined based on whether or not the first POC difference between the current frame and the L0 reference frame and the second POC difference between the current frame and the L1 reference frame are identical, wherein the prediction samples for the current block are derived by applying BDOF to the current block based on BDOF flag information indicating whether or not to apply BDOF to the current block.
EFFECT: increasing the efficiency of image encoding/decoding.
3 cl, 12 dwg, 30 tbl
