In some cases, pairwise average candidates are generated by averaging predefined pairs of candidates in the current merge candidate list, and the predefined pairs are defined as {(0, 1), (0, 2), (1, 2), (0, 3), (1, 3), (2, 3)}, where the numbers denote the merge indices to the merge candidate list. The averaged motion vectors are calculated separately for each reference list. If both motion vectors are available in one list, these two motion vectors are averaged even when they point to different reference pictures; if only one motion vector is available, use the one directly; if no motion vector is available, keep this list invalid. The pairwise average candidates replaces the combined candidates in HEVC standard. Suppose the MVs of two merge candidates are MV0=(MV0x, MV0y) and MV1=(MV1x, MV1y), then the MV of the pairwise merge candidate denoted as MV*=(MV*x, MV*y) is derived as MV*x=(MV0x+MV1x)/2, and MV*y=(MV0y+MV1y)/2.