Disclosed herein are a video encoding/decoding method and apparatus. The video decoding method of the present disclosure includes: obtaining block partitioning information of a current block; based on the block partitioning information, partitioning the current block into a first sub-block and a second sub-block; deriving motion information of the first sub-block and motion information of the second sub-block respectively; based on the motion information of the first sub-block and the motion information of the second sub-block, generating a prediction sample of the first sub-block and a prediction sample of the second sub-block respectively; and through a weighted-sum of the prediction sample of the first sub-block and the prediction sample of the second sub-block, generating a prediction sample of the current block. Herein, the block partitioning information is index information indicating an index of a table including information indicating a plurality of predefined asymmetric partition shapes.