Temporal motion prediction for fast motion estimation in multiple reference frames

In the new video coding standard, H.264/MPEG-4 Part 10, motion compensation is allowed to use multiple reference frames that improves the rate distortion performance but at the cost of drastic increase in complexity. The increased computation is in proportion to the number of searched reference frames. However, the reduction of prediction residues is highly dependent on the nature of sequences. In this paper, we present a fast technique to predict the motion vector in reference frames to speed up the matching process for multiple reference frames. The proposed technique is based on choosing the motion centre and carrying the search around the centre with a radius of 1 or 2 pixels in all reference frames which exception of the one which immediately precedes the current frame. For the reference frame that immediately precedes the current frame any motion estimation technique can be used. The results show that the proposed technique reduces the computational requirements down to that required for single reference frame motion estimation with only a negligible loss of objective quality.