Abstract
Recently, many people keep working with an emphasis on enhancement of the video quality on wireless network. The real-time video application on network is increasing and the demand of users growing. However, when the video packets are transmitted on network, they may be lost due to network congestion or unstable bandwidth. It not only affects the quality of current frame, but also leads to error propagation to subsequent frames because of motion compensated prediction techniques used in standard video codecs.The loss of packets is a serious problem. To solve it, error tracking was proposed several years ago, the main idea is to predict the propagation of errors and encode some blocks as intra block. If we lost some packets when transmitting, the intra blocks will stop the error propagation and recover the image quality quickly. Here, we propose a new algorithm to locate the error and tracking the error propagation quickly. It enhances the efficiency of the intra refresh coding. The proposed algorithm can adaptively vary the intra refresh rate according to the video content and the packet loss to protect the most important macroblocks against data loss. For real-time application, the speed of error tacking is considered. In this thesis, we show the simulation results of the error tracking algorithms with different propagation length and the performance of tracking scalability. The setting of intra-refresh threshold is adaptive to erroneous MBs and the intra-refresh becomes more effective. Due to the high accuracy of error prediction, the scalability of error tracking still works well.