A method of constructing a uni-directional motion vector merge list for triangular shape processing units (PUs) in the triangle prediction mode of video coding standards, such as the current Versatile Video Coding (VVC), is performed at a computing device. The computing device constructs the motion vector merge list for the coding unit (CU) containing the triangular shape PUs, and then constructs the uni-directional motion vector merge list for the triangular shape PUs based on the motion vector merge list for the CU.