Motion Estimation for Real Time Transmission on H.264/AVC

Motion estimation (ME) limits the performance of the encoder in terms of encoding speed and image quality. However, its complexity is too high to be applied in real time applications. To reduce its complexity and maintain the image quality, the proposed method uses a hierarchical search strategy for integer pel ME. This strategy consists of symmetrical cross search pattern, multi-square grid search pattern and diamond search patterns. This hybrid search strategy places search points symmetrically and evenly that can cover the overall search area not to fall into the local minimum and to reduce the complexity. Experiment results show that the speedup improvement of the proposed method over unsymmetrical-cross multi-hexagon grid search (UMHexagonS) and full search (FS) can be up to 1.2 square 6.6 times faster respectively. Compared to FS, the proposed method shows an average PSNR drop of 0.01 dB while showing an average PSNR gain 0.01 dB in comparison to UMHexagonS.