| Multimedia service, based on streaming media technology, was applied abroad on the Internet. People never stop pursuing multimedia service of high quality for a moment. However, the limitation of bandwidth still is the bottleneck of the development of high quality multimedia service. How to provide high quality mulimedia service on limited bandwidth becomes the focus of research field. H.264/AVC, which has outstanding compress performance and strong robustness, is a new video compress standard, issued by the joint video team (JVT) consisting of the members of MPEG and the ITU's Video Coding Experts Group. It is very suitable for network transmission. Based on the background, we research and develop the Video On Demand(VOD) system for H.264. Because IP network provides best effort service, the video data packet may lost during network transmission. However, due to high compress rate, in contrast with previous video compress standards, the influence of data packet loss will make more serious effect over H.264 bitstream.Therefore, this thesis mainly discusses the design and implementation of the client of the VOD system. Our major contributions are listed as follow. First, we design and develop the client of the VOD system. We implement basic function for user operation,such as connection of the client, programme order, play,pause. We also propose a sorting algorithm to deal with out-of-order of RTP data packet. And a algorithm for auto-adjustment of ring buffer size is developed as well. This algorithm may reduce the impact of delay jitter during data packet tansmission. Second, we propose a new real-time error concealment algrithm ,based on the new feature of H.264. We predict the lost Macroblock partion model and motion vector by using of the Macroblock partion model of around Macroblock. The experiment result shows that the algrithm meets real-time need, and the object quality is great improved ,compared with Bilinear interpolation algorithm. |
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