An Improved Multiple Description Coding Strategy Based on Path Diversity

In this paper, a source coding technique exploiting packet path diversity is presented, which combines the individual benefits of MDC (multiple description coding) and LC (layer coding) for video transmission over wireless networks. Performance comparisons between LC and MDC are discussed at the beginning of this paper. Their advantages and disadvantages are concluded. An improved coding technique named auto-resilient multiple description coding (ARMDC) is then shown for its ability to conjoin the merits and avoid the shortcomings of the above two coding schemes. Under the critical transmission conditions of error-prone wireless channels, ARMDC can make all the received packets useful, not just those consecutive from the first packet. At the same time, it can also process the feature of LC, creating a “base-layer” bit-stream to ensure the basic quality of video. Transmission policy of ARMDC varies with transmission environment and application limits to gain fine video quality. 3G mobile channels are simulated and then streams create by ARMDC, MDR (multiple description with restart) scheme and coding scheme without any LC or MDC are sent over the channels. Experiment results show that the decoded video sequences of ARMDC streams have better performance in R-D curve comparision than the other MDC scheme and also gain best personality effect because of the smooth sequence quality. This out-coming is well adapted to streaming and conversational applications in wireless environment.