Rate-constrained motion estimation algorithm for video coding

We propose a rate-distortion-constrained motion estimation algorithm that leads to improvements in motion-compensated video coding. This is especially true in low bit rate video coding applications such as video conferencing. We introduce the concept of coding efficiency, and the rate-distortion optimization process is formulated as a problem of maximizing coding efficiency. Based on the coding efficiency, the proposed motion estimation algorithm measures the effect of choosing different motion vectors on the overall bit rate and reconstruction distortion. The main advantages of the algorithm are that it employs a more effective measure of performance and it is computationally simple. Our experimental results show that our proposed rate-constrained motion estimation algorithm yields better rate-distortion performance when compared with conventional motion estimation algorithms.