Research On The Mobile Video QoS Key Technology

With the development of mobile Internet technology, especially the3G era, mobile videoapplications are more and more, by user favorite. However, the current mobile network alsohas some shortcomings. The mobile video technology should solve the problem of theerror-prone and the unsure quality of service. Real-time mobile video is morechallenging. Real-time mobile video technology has broad application in the social securitymonitoring, video conferencing, video and television, and has broad prospects fordevelopment, that multimedia technology research focus.In this paper, based on the project "Mobile video surveillance network managementplatform" of the laboratory and the research on the QoS related technology of videotransmission, get in-depth study on the mobile video dynamic congestion control and adaptiveerror recovery techniques for video data transmission.To solve the congestion during the video data transmission on the network that thebandwidth constantly changing, this paper propose the congestion control algorithm base onRTCP in the project with multicast way. This algorithm gets the feedback message from thereceiver by means of RTCP protocol, and analyzes the status of the receiver, so that we canadjust the bit rate of the video. According to the state of the receiver, the sender uses multiplevideo streams for multicast mode, which uses a variety of bit rate encoding for single-channelvideo. In order to be able to adapt more receivers, the sender takes a quantitative parameterfine-tuning for the encoding video stream ensure that the transmitted video bit rate is moresuitable for the majority of the receivers.In order to mitigate the impact of network packet loss for video decoding, this paperpresents an error recovery technique for the mobile video. The technology uses forward errorcorrection technology with the RS error correction coding, which can be effectively on thewrong data recovery. Meanwhile, in order to adapt to the network conditions of the receiver,this paper presents the adaptive approach, provides a variety of error correction codingschemes, so that the redundant data generated in the coding would not produce congestion onthe network transmission process. For the H.264encoder, there are importance distinctions of the video sequences. This paper presents the unequal protection for video sequences, therebyreducing the impact of packet loss for video decoding.Finally, it describes the results of system testing and application. The test results showthat, despite the state of the wireless network is constantly changing, the algorithm of thepaper can adaptively adjusts the video transmission rate, reduces the video transmissionprocess generated by congestion problem. Compared with not using the system of adaptiveerror recovery, error recovery scheme proposed in this paper effective data protection andimprove the quality of decoding the video transmission, and the case of bit rate increase isvery small. It can be seen from the results of the actual project application, the algorithms canachieve good results.