A Multi-layer motion estimation scheme for spatial scalability in H.264/AVC scalable extension

In this paper, we propose a fast multi-layer motion estimation algorithm for spatial scalability provided in H.264/AVC scalable extension, based on the reuse of the motion vectors from multiple spatial layers. The reused motion vector is used to set a search center and refined within a small search area. However, the reused motion vector often produces significant prediction error at object boundaries. Motion vector difference defined in the H.264/AVC standard is used to decide whether the reused motion vector is appropriate. In addition, a search range is dynamically adjusted based on the distribution of the rate-distortion cost. By using the proposed multi-layer motion estimation, we reduce the execution time of motion estimation by almost 93% at the cost of 0.01 dB PSNR decrease and 0.79% bit-rate increase.