Fast multiframe motion estimation algorithm in H.264

In the new MPEG-4 AVC/H.264/JVT video coding standard, motion estimation is allowed to use multiple reference frames, which takes up a significant encoding time especially when using the straightforward full search algorithm (FS). However, the reduction of the prediction residues is not proportional the number of reference frames. In this paper, we first analyze the distribution of used reference frames and the efficiency of multiple reference frames, then a fast multiple reference frame motion estimation algorithm is proposed based on the assumption that correlation between frames decreases according to their interval. Extensive simulations show that this algorithm can reduce about half of reference frames, while the loss of the output quality of encoded sequences is less than 0.05 dB. In addition, this algorithm can be used with any fast motion estimation search algorithm.