Bidirectional motion estimation based on P frame motion vectors and area overlap

Some proposed video compression schemes do not send frames in the order they were captured. Such schemes yield bidirectional or B frames: frames that are predicted from past and future frames. When estimating motion vectors for B frames the motion vector field referencing the future to the past frame (the P frame motion vector field) is available. The area overlap (AO) method presented estimates the motion vector fields relating a B frame to past and future frames using the P frame motion vector field. Thus B frame motion vectors need not be sent AO's estimates are scaled versions of P frame motion vectors and therefore have finer resolution.<>