Research And Implementation Of Mobile Cloud Computing Based Streaming Media Transcoding System

With the current rapid development of Mobile Internet, mobile video is becoming an important part of the online video ecosystem. Users are gradually developing the habit of watching video via mobile terminal, and the network video users of mobile terminal has reached a high level. Existing network streaming protocol has three major categories, connection-oriented transport such as Real Time Streaming Protocol, HTTP progressive download and Adaptive bitrate streaming. Dynamic Adaptive Streaming over HTTP (DASH) is an Adaptive bitrate streaming technology, combined with the other two techniques to their strengths, can automatically adapt to network conditions to provide different quality of online video. Traditional DASH technology provides only a few fixed bit rate of video segments for client choice, and therefore has lower network adaptive flexibility. In a particular scenario, if a group of adjacent users watch a same online video, the network ability of each user will reduce due to the competition among the group, thus affecting the video quality that they are viewing.In this paper, against the issues that the group competition affects streaming media viewing experience in the scenario described above, an improved network of streaming media transmission system that is called M-DASH is proposed. On the basis of DASH, media resources are transcoded using mobile cloud computing technology, in order to make the transmitted of video slices more fitting to the current network capacity, and to enhance the flexibility of the network adaptive capacity. On the other hand, neighboring cooperation takes full advantage of the user’s network capabilities, and network capability of a single user is expanded by device-to-device (D2D) connection. Through the validation by building a test bed platform, the M-DASH system can provide better video quality for viewing than existing systems, and can optimize the user experience.In this paper, the first chapter briefly introduces the basic mechanisms of DASH protocol, describes the scene that will be focused on, and presents a comparison of the existing domestic and foreign research progress. Then in the second chapter, the improved M-DASH system is proposed, which can optimize the user experience to these specific scenario with the help of mobile cloud computing technology. After that the research is focused on two key issues in the proposed system. Rate selection algorithm is discussed in the third chapter, and the device-to-device transmission is introduced in the fourth chapter. At last, the fifth chapter discusses system performance, and the sixth chapter introduces summary and outlook.