Research And Implementation Of Audio System Based On WebRTC Echo Cancellation

Recently,audio and video instant messaging technology has been widely used in medical,military,education,security control and other application fields.However,with the widespread application of audio and video instant messaging in various scenarios,the existing technology presents many deficiencies,such as unsynchronized audio and video,echo interference,and difficulty in guaranteeing transmission quality.The presence of echo affects the quality of voice communication,to a large extent,resulting in loss of call quality,which is an important issue to be solved urgently.In order to eliminate echo,researchers have carried out extensive and in-depth research on it.Nowadays,great progress has been made.In order to better promote the construction of digital campus,this thesis aims to eliminate the echo in audio and video instant messaging,and focuses on the research of unstable acoustic echo cancellation.The main works of this thesis are as follows:1.This thesis studies the related theories of Web RTC,including its development status,application fields,overall framework and core technology,and in-depth study of the seven major components of Web RTC,open source API and Web Socket protocol.Thesis focus on the analysis of the implementation principle of the Web RTC echo cancellation module,and in-depth study of the Least Mean Square(LMS)and Recursive Least Square(RLS)algorithms in the Web RTC adaptive filter.Analyzing the advantages and disadvantages of the two various types of algorithms.Make certain theoretical preparations for the method proposed in this thesis.2.The LMS algorithm has low computational complexity and is easy to implement,but its convergence effect is not good.To solve this problem,thesis further researches and improves the normalized least mean square(Normalized LMS,NLMS)algorithm on the basis of the LMS algorithm.Verification by the simulation experiment platform and experimental results show that the improved NLMS algorithm has the advantages of fast convergence,low steady-state error and strong tracking ability compared to the LMS algorithm and the typical NLMS algorithm.3.Design and implement a classroom conference system based on Web RTC echo cancellation.The development process of the system includes architecture design,serverside configuration and deployment,and client-side design and implementation.This thesis selects SFU as the communication framework of the system.The server-side work includes the deployment of three modules,namely the streaming media module,the signaling module,and the network address translation penetration module.The client’s work includes environment construction,communication principle research and implementation of various functional modules.4.Under the case of multi-user circumstances,this thesis tests the system function modules and collects relevant data for performance analysis and echo cancellation analysis.The test results show that the system has the advantages of cross-application platform,stability and low power consumption.Finally,the actual classroom scene application shows that the system has practical application value.