Research On Adaptive Streaming Media Transmission Technology Based On DASH

With the popularity of Internet and the rapid development of mobile communication technology,the application of streaming media which based on multimedia technology is more and more widely.The traditional Internet can effectively transmit the text,graphics and other discrete media,but it faces a huge challenge in transmiting a large number of real-time continuous audio and video media data.Transmiting real-time continuous data with stream can be a good way to deal with this challenge.However,with the consistent growth in the application of streaming media,the traditional streaming media technology shows a variety of shortcomings in practice,such as network heterogeneous,can not through the firewall,server deployment complex,high maintenance costs.Streaming media technology based on MPEG-DASH protocol can optimize these problems by combining the advantages of HTTP progressive download technology and adaptive transmission technology.This paper mainly studies the adaptive system and key technology of streaming media which based on DASH protocol.Firstly,this paper describes some challenges which streaming media technology faces in the background of the growing demand for its application,thus people use the adaptive streaming media transmission technology to deal with these challenges.Then the paper studies the streaming media system and its protocol stack,and the format of media presentation description file and slice principle about DASH technical standard.By building a simple adaptive streaming media system and studing the adaptive bit rate selection algorithm in the player client,this paper points out the shortcomings of the built-in algorithm in choosing the optimal bit rate.To optimize the adaptive bit rate selection algorithm,the mathematical model of the client adaptive transmission algorithm is studied.On this basis,an adaptive bit rate selection algorithm combining the rate and the client buffer is designed.Finally,in NS-3,the asymptotic switching algorithm and the designed algorithm for fixed and changing network bandwidth scene are experimented and the overall performance is compared.The simulation results show that the proposed algorithm has a stable high speed and the playback is feasible under the fixed network bandwidth.In the case of bandwidth change,the designed algorithm shows better adaptability,which not only improves the network bandwidth utilization,but also improves the quality of the user's video experience.