A video processing method includes constructing, for a conversion between a current block of a video and a bitstream representation of the video, a motion candidate list with at least one motion candidate; and determining, based on a candidate type of a first motion candidate, whether a generalized bi-prediction (GBI) processing tool is enabled. The GBI processing tool comprises deriving a final prediction based on applying equal or unequal weights to predictions from different reference lists according to a set of weights. The method also includes performing the conversion according to the determining.