A method for video coding is provided. The method includes obtaining a first reference picture and a second reference picture associated with a current prediction block, obtaining a first prediction L0 based on a first motion vector MV0 from the current prediction block to a reference block in the first reference picture, obtaining a second prediction L1 based on a second motion vector MV1 from the current prediction block to a reference block in the second reference picture, determining whether a bidirectional optical flow (BDOF) operation is applied, and calculating a bi-prediction of the current prediction block based on the first prediction L0 and the second prediction L1, and first gradient values and second gradient values.