Research On Error Resilient In Wireless Video Communication

Recently, with the development of the wireless network, the requirement of multimedia applications is growing fast. Because of the huge data of multimedia and video data, video signal is usually compressed highly to reduce the redundancy for the demand of the narrow bandwidth. So the compressed data will be more sensitive to the transmission error. And the reconstructed pictures will be badly damaged, even can't be decoded. The characteristics of the wireless channel are high bit error rate and packet loss rate. Wireless video communication needs appropriate and effective error resilient technology to provide the guaranteed quality. The work introduced in this thesis has researched the error resilient technology suit for wireless video communication.Firstly, a brief introduction of video compression technologies and standards is given. Then, the key technologies and characteristics of some important video compression standards are analyzed in detail. And the main research of this thesis is explained.After that, the error detection method is introduced. Then, a detailed analysis of some error resilient technologies and their principle is given. These technologies are typical and have mature research achievements. Many characteristic error resilient tools in H.264/AVC standard are deeply researched. And the introduction of flexible reference frame (FRF) in AVS standard, the fully intellectual property of second generation source coding-decoding standard which is owned by China, is given.Temporal error concealment, spatial error concealment, frequency error concealment and adaptive spatial/ temporal error concealment methods are introduced respectively. Every kind of methods has its own advantages and disadvantages. We need to choose them according to the specific video sequence and error condition. Considering the characteristic of wireless communication, a new adaptive spatial/ temporal error concealment method is proposed. Experiment results show that it can obtain much better picture performance than the error concealment algorithms in H.264/AVC standard. The higher bit error rate is, the better performance obtains.Changing the macroblock order is an effective method to combat channel errors. According to that, a macroblock order strategy, which is suit for real-time communication, is proposed. This strategy has better results by avoiding continuous error. Then a combination of the adaptive spatial/ temporal error concealment method and this strategy is researched. Experiment results show that this combined error resilient method is better than the error resilient tools in H.264/AVC standard.Lastly, a conclusion of this thesis and the discussion of future research directions are given.