Design And Implementation Of SIP-Based Signal Processing And Audio And Video Slice Transmission Mechanism

With the development of human society,more and more smart products have entered our lives.The SIP protocol is adopted by many smart devices as a signaling protocol due to its flexible and open features.In terms of streaming media servers,there are mainly HTTP progressive download servers and RTSP-based real-time streaming media transport servers.The SIP-based smart device systems usually use the latter.However,since the SIP protocol only specifies the manner in which the session is opened,the audio and video codec process and transmission mode of different smart device systems may be greatly different,which is not conducive to the development of the decoding module of the terminal and the development of the cache module of the server.It increases system development cycle and difficulty.If the streaming media server adopts HTTP progressive downloading,although it can develop fast,easy to adapt,and own cache function,it will generate a large delay,which is obviously not practical for the application scenario of real-time video interaction.Moreover,frequent read and write operations of such streaming media servers can cause a rapid decline in hard disk performance,which is also a disadvantage for server hardware maintenance.In order to solve the above problems,this thesis designs a SIP-based signaling interaction and audio and video slice transmission mechanism,and implements the server-side functions.The main interactive signaling designed in this thesis is based on the SIP protocol.The audio and video processing method is based on the HLS protocol.The method of writing the memory into the memory by the slice file and the innovative process design use a variety of algorithms to solve the long delay of the original HLS streaming server.The problem of slow performance of the hard disk.Compared with the traditional SIP intelligent device system,the design of this thesis has the advantages of low latency,fast development,wide compatibility and strong scalability.In terms of the terminal,the development time of the terminal will be greatly shortened,and the advantage is more obvious for the smart device system that requires multiple types of terminals.The main work and results of this thesis are as follows:(1)The SIP-based signaling interaction process is designed,including login,keepalive,video session establishment,and video session shutdown.The signaling is based on the SIP protocol,and uses tags such as REGISTER,INVITE,and BYE specified in the protocol.The module processing flow of the server in interaction is designed,including how to implement port allocation,push file generation,and port release.(2)A streaming media server based on HLS slicing is designed.The designed modules include FFmpeg push stream module and streaming slice and response module.The FFmpeg push stream module is a media stream preparation module.The streaming media slicing and response module is the core module of the streaming media server.The module does not use the traditional HLS server slice generation method,but stores the slices directly in the memory.The module flow is designed with full consideration of possible details such as slice file replacement,index file coverage,and file retrieval difficulties.The related processing mechanism is designed to reduce system delay and improve real-time performance.(3)For the previous design,using Python language,combined with SQLAlchemy framework,Mysql database,open source FFmpeg and other technologies,to achieve a server with the corresponding functions.The implemented server includes three parts: database server,signaling server and streaming server.The signaling server and streaming server are the core function servers in this design.(4)Test the implemented server.The tested terminal adopts the SIP terminal and the VLC streaming media player after the signaling transformation,and the test is mainly based on the testing of each functional module,including the testing of the signaling system,the testing of the video delay,and the testing of the server traffic load.Tests have shown that the design of this thesis is in line with expectations.(5)Suggestions for optimization of server processes and functions are provided as research content for such servers in the future.