Joint Source Channel Coding Technique Research Based On Scalable Video Coding

In recent years, with the rapid development of fundamental technologies such as computer, communication and network etc, video communication has been widely applied. The scalability is one of the most important features for video streams. However, this kind of bitstreams are very sensitive to packets loss and bit errors in transmission channels. Even if a single bit error occurs , it can be probable that all remainning bits will not be decoded correctly. On the other hand ,the Internet and wireless networks nowadays are lossy and cannot provide reliable data transmission in real time. As a result, one challenging problem is to transmit scalable bitstreams reliably and efficiently over noisy channels.Joint source channel coding(JSCC) is one of the important methods to cope with the problem of reliable transmission of image and video in real time. Based on scalable video bitstreams and LDPC technology, the key technology in JSCC is studied in this thesis. The main contributions and innovation points are as follows:(1) A novel rate allocation algorithm is proposed , which allocates bit rate jointly for source and channel by Particle Swarm Optimization(PSO) method. In this thesis, rate allocation in JSCC is better solved by PSO algorithm. Experiments show that the algorithm is simple to implement and easy to find the optimal solution with low complexity.(2) Studies on distortion-based optimal and rate-based optimal criterion are made, with analysis on characteristics of these two criterions. Better effect is achieved under the distortion-based optimal criterion while low complexity is needed with rate-based optimal criterion.(3) JSCC scheme under multicast scenario is given. For multi-user transmission with different target rate and packet loss rate, the proposed scheme can significantly reduce the number of computing rate allocation and the complexity of transmission system for scalable bitstreams.Finally, the summary of this thesis is made, and future direction on the JSCC is discussed as well based on the work of this study.