Design And Implementation Of Streaming Media Video Transmission System Based On MPEG-DASH

With the development of the Internet and the involvement of many smart terminal devices, the demand for the Internet streaming video services is increasing. The traditional streaming video transmission technology with limits of the protocol is difficult to solve the problem when transmitting the video stream, like traversing the firewall and NAT etc. The adaptive streaming technology base on HTTP can solve the problems above effectively which has become a hotspot of research.MPEG-DASH transmission protocol is a cross platform standard streaming media video transmission protocol launched by MPEG organization. It is becoming more and more popular and accepted. It has great research value and development potential. In this paper, we analyzed the MPEG-DASH protocol, in addtion, the related rate switching algorithm that suitable for the client is studied, and a streaming media video transmission system is implemented based on the protocol.One significant advantage for rate selection algorithms based on bandwidth estimation is the high bandwidth utilization rate. They are, however, vulnerable to network bandwidth fluctuations, leading to appearance of rate instantaneous peak value and hence wasting unnecessary bandwidth consumption. To tackle the problem above, this thesis designs a novel rate selection algorithm based on the contrast sensitivity of human eyes, where in the client eyes cutoff spatial frequency under the current viewing conditions is calculated by using the human contrast sensitivity model. The algorithm selects the rate of video fragment which has the minimum absolute difference value to the spatial frequency computed, stored in server as the target rate. Compared with those methods calculating the target rate based on bandwidth estimation and testing target rate in different angles, the proposed method gets the ladder diagrams of rate calculation of both methods. Experimental results demonstrate that the proposed algorithm is able to save a considerable amount of bandwidth without the loss of video quality, with viewing angle from 5 to 15 degrees.In this thesis, we implement the system with the the MPEG-DASH framework by using the method that was mentioned above.Besides, we provide the detailed information and technologyies that are adopted by each component of the framework.Then we discussed the selection of some important parameters used in our system, and furthermore we analyzed results which are carried out by experiments. Finally, the system is tested in a real environment. The results show that the video transmission system can bring good user experience and has certain value of applying.