Method and apparatus of inter prediction using average motion vector for video coding

An apparatus of video coding utilizing a motion vector predictor (MVP) for a motion vector (MV) for a block coded in Inter, Merge, or Skip mode, wherein the MV is associated with one given block and one corresponding reference block in a given reference picture in a given reference list, the apparatus comprising one or more electronic circuits or processors configured to:

• receive input data associated with a current block in a current picture;
• derive a current candidate list for the current block based on MVs (motion vectors) associated with neighbouring blocks of the current block according to a pre-defined order, wherein each candidate in the current candidate list includes one MV (motion vector) associated with list 0 or list 1 for uni-prediction and each candidate includes two MVs (motion vectors) associated with both list 0 and list 1 for bi-prediction;
• derive a mean candidate from at least two candidates in the current candidate list, wherein the mean candidate includes two MVs for the bi-prediction or one MV for the uni-prediction, and at least one MV of the mean candidate is derived as a mean of the MVs of said at least two candidates in one of list 0 and list 1;
• add the mean candidate to the current candidate list to form a modified candidate list;
• determine, from the modified candidate list, one selected candidate as a MVP (motion vector predictor) or MVPs (motion vector predictors) for a current MV or current MVs of the current block;
• and
• encode or decode the current block in Inter, Merge, or Skip mode utilizing the MVP or MVPs, wherein a MVD (MV difference) or MVDs (MV differences) between the MVP or MVPs and the current MV or current MVs respectively along with prediction residuals of the current block are signalled for the current block coded in the Inter mode, wherein an index indicating the selected MVP in a Merge candidate list along with the prediction residuals of the current block are signalled for the current block coded in the Merge mode, and wherein the index indicating the selected MVP in the Merge candidate list is signalled for the current block coded in the Skip mode without the prediction residuals of the current block.