A decoding method includes the following. A bitstream is parsed to determine first flag information, where the first flag information indicates that a DIMD Merge mode is used for a current block. Multiple search positions around the current block are determined according to the first flag information, where the multiple search positions include a spatial non-adjacent position of the current block. Gradient information to be blended is determined according to the multiple search positions. A prediction value of the current block is determined according to the gradient information to be blended.