IMAGE DECODING DEVICE, IMAGE DECODING METHOD, AND PROGRAM

An image decoding device includes: a prediction signal generation unit configured to determine whether or not an application condition of Bi-Directional Optical Flow (BDOF) processing is satisfied for each block, generate a prediction signal by executing the BDOF processing in a case where it is determined that the application condition is satisfied, and set the application condition based on a weight coefficient in a case where calculation is performed using pixel values of two reference frames or values calculated from the pixel values in the BDOF processing such that the application condition includes a condition on time distances between the two reference frames and a target frame.