Research And Implementation Of Streaming Media Transmission System Based On SRT Protocol

With the rapid development of Internet technology,the proportion of online video service users is increasing year by year.Compared with traditional TV media,online streaming media is famous for its flexibility and diversity,and has strong vitality.In the streaming media transmission,there is a triangular relationship among cost,delay and quality.It is necessary to find an optimal balance between the three,and real-time is the first factor to measure the transmission quality in the streaming media system.At present,the mainstream RTMP(real time messaging protocol)protocol uses TCP(transmission control protocol)protocol.In the network environment with large fluctuations,its performance in all aspects is degraded.To solve this problem,this thesis studies the new SRT(secure reliable transport)protocol,builds a streaming media transmission system,and compares the push and pull streams.The results show that the first delay performance of SRT is improved by 3 to 4 times under the same delay,and it has relatively good anti-jamming effect and visual experience in the packet loss network environment,The classic SRT streaming media transmission system has the problems of high delay and active data dropping when facing network congestion.To solve this problem,this thesis studies the SRT packet loss retransmission strategy,gives the mathematical model of delay and bandwidth overhead through theoretical analysis,and verifies the relationship between delay,delay and rate through simulation.On this basis,the BBR(bottleneck bandwidth and RTT)algorithm is studied.Through simulation and comparison,the advantages of BBR algorithm based on bandwidth and delay are verified.Furthermore,an adaptive dynamic coding rate control algorithm based on BBR algorithm is proposed and applied to improve the performance of SRT protocol under the condition of network bandwidth fluctuation and random packet loss.Through the construction of streaming media transmission test system,it is verified that the delay and fluency performance of the proposed algorithm are better than the original SRT protocol,and it has obvious advantages in the scenarios where the link state is difficult to predict or the network environment fluctuates greatly.