Research On H.264 Motion Estimation Algorithm And Its Application In Scabale Video Coding

Demand for multimedia information is increasing sharply nowadays, benefited from the development of information processing techniques and network communication technologies. And the video coding technology is an important part. Because of the advantage in compression rate and network transmission, the newest H.264 video compress coding standard, is recommended as the primary video compress coding technology. But the high encoding complexity of H.264 limited its widely employmet in applications. How to decrease its complexity while keeping its excellent performance, and make the video coding technology adjust to different application environment, thus promoting the standard's practicality, is the problem we'll solve.In this paper, the video coding process of H.264 standard is introduced first. And motion estimation techniques, which is the most complex part of H.264 coding process, is analyzed, then most of motion estimation algorithms are summarized and compared with each other with a diagram. Then the Scabale Video Coding of H.264 extend standard is briefly introduced.By analyzing the motion estimation in H.264, laws of correlation between values of Rate Distortion Optimizition and block sizes and reference frames were found. A fast motion estimation algorithm is proposed. The algorithm predicts the searching starting point, and runs global multi-accuracy sampling search, then runs 2-step fine search with multi-patterns, then run diamond search for 1/4 sub-pel motion estimation. making use of the laws mentioned above, the sampling search applys adaptive sampling pattern and candidate point, and several new adative thresholds are introduced to confirm the optimal solution or eliminate the bad candidate. Experimental results show that, compared with UMHexagonS algorithm in different kinds of test sequences including HD format, the proposed method averagely reduces 32% of motion estimation time with almost the same R-D performance and bit rate.For network systems with very different performance, the H.264 scabale video coding technoque procudes streams with different rates adaptive to network environment and service quality. H.264 Scabale Video Coding system is introduced. The proposed fast motion estimation algorithm is employed in the system, and by including predicting layer coding mode, test complexity of the system. The result shows a promotion in svc speed is visible.