Research And Realization Of Streaming Media Transmission Scheme Based On SIP

With the arrival of the mobile Internet era,the streaming media market is expanding at a high rate.It is widely used in video conferencing,video surveillance,distance education and many other aspects,gradually replaced the picture and text-based traditional Internet.Therefore,research on media transmission technology is more and more important.In this thesis,we divide the application scenario about streaming media into two categories,one is similar to VOIP,a one-to-one transmission;the other is like the live scene which is a one-to-many transmission way.Two kinds of SIP-based streaming media transmission schemes are implemented for these types of scenarios.First,the program of ICE traversal Symmetric NAT based SIP is optimized and implemented for the point-to-point transmission scenarios.A new intelligent discovery mechanism of NAT type is proposed in the process of connectivity detection,and the complex and cumbersome detection process of traditional ICE is discarded,which support the stable premise for the implementation of port prediction algorithm.The hard problems of incremental selection Symmetric NAT traversal is successfully solved by the improved port prediction algorithm,meanwhile taking a certain strategy to avoid the predicted port has been occupied;Traditional connectivity testing process is optimized,making the connection time reduced.Second,a point-to-multipoint transmission strategy is achieved on the basis of point-to-point transmission scheme.The defect of live555 is made up.In order to guarantee video quality in poor network,the video data is pushed by the way of RTP over TCP;at the same time,the delay frame strategy is designed and implemented to reduce the delay of real-time video screen;and the data obtained from the server as the source of unpacked data which is successfully displayed to achieve a multi-user expansion.Finally,we designed a set of network audio and video monitoring systems running in different network topologies.Of course,a large number of test schemes,data collection and result analysis are carried out to verify the correctness and practicability of the scheme.