Study And Realization On Real-time Transmission Of Streaming Media Based On DirectShow

With the rapid increasing of network bandwidth, the real-time transmission technology of streaming media data has been becoming one of the key researches on the area of modern network technology in recent years. However, the current best-effort Internet does not offer any quality of service(QoS) guarantees to real-time streaming media, because its bandwidth and delay change with time. Under this background, this paper researches the framework of DirectShow and the real-time transmission of streaming media deeply, then designs and realizes the basic audio transmission system based on DirectShow framework and RTP/RTCP protocol, the system realizes living broadcast service of streaming media using G.723 codec and RTP/RTCP protocol.Firstly this paper summarizes the development, appliance, existing problems of streaming media technology and DirectShow appliance, then puts forward software design pattern based on DirectShow framework on the basis of analyzing the framework DirectShow deeply, this pattern solves the problem of reuse in software. On the basis of being familiar with the basic principle and the architecture of streaming media transmission, establishes the total solution of the streaming media transmission system, including the designment of thread structure, total structure, server end, client end, sending filter and receiving filter, confirms C/S model of system and compartmentalizes main function model of system. Subsequently, describes particularly sending and receiving RTP and RTCP packet in server and client. Finally, this system analyzes the adaptive control of streaming media transmission in detail, including TCP-friendly congestion control, error control, parameter computing and the strategy of feedback in receiving end and adjustment of sending end.The audio transmission system based on DirectShow framework has been applied to the environment of LAN. The system solves finely the problems of jitter, error, loss order in the transmission process of real time streaming data, and obtains better communication effect.