Patent ID: 8345758

Claim:
A method of deriving a list 0 and list 1 motion vectors of a bi-predictive block in a current picture from a motion vector of a co-located block in a first reference picture, performed by a moving picture coding system, comprising: selecting, by the moving picture coding system, a list 0 motion vector of the co-located block in the first reference picture as the motion vector for deriving the list 0 and the list 1 motion vectors of the bi-predictive block regardless of whether the co-located block has a list 1 motion vector if the co-located block has the list 0 motion vector, the first reference picture being a type of reference picture permitted to be located temporally before or after the current picture; deriving, by the moving picture coding system, a first temporal distance between the current picture and the second reference picture which is referred by the co-located block in the first reference picture; deriving, by the moving picture coding system, a second temporal distance between the first reference picture and the second reference picture; scaling, by the moving picture coding system, the selected list 0 motion vector of the co-located block based on the first and second temporal distances; and deriving, by the moving picture coding system, the list 0 and the list 1 motion vectors of the bi-predictive block based on the scaled list 0 motion vector of the co-located block.