Research On Technology Of VoIP High Quality Audio And Video Transmission

Internet have been applied to all aspects of our lives.With the rise of mobile Internet technology,such 3G and 4G,Vo IP(Voice Over Internet Protocol)technology has gradually become popular.Compared with traditional mobile phone,Vo IP has the advantage of low cost,simple deployment,and customization.But the Communication quality of Vo IP depends on the quality of Internet.It is not easy to guarantee the communication quality.In Vo IP audio and video communication,there are various factors such as echo,noise,and carton that has an influence on the quality of Vo IP communication.In order to make Vo IP more widely used and achieve high-quality audio and video communication in the mobile Internet,these defects must be optimized.This paper discusses how to improve the audio and video quality in Vo IP communication.After analysis the source code of Web RTC which is an open source project of Google,this paper discusses the feasibility of using Web RTC voice engine in Vo IP so that we can use the Web RTC technology in Vo IP.This paper used the echo cancellation module of Web RTC audio engine in Vo IP to eliminate echo.Compared with the traditional open source AEC(Acoustic Echo Cancellation)module such as Speex,the Web RTC AEC module shows better performance.In addition,for the case that the Web RTC noise suppression module shows poor performance in complex noise sources,this paper proposes an audio noise suppression method based on neural network which use GRU to suppress noise.It is proved that the neural network shows better performance than Web RTC noise suppression module by experiment in different noise environments.In terms of video communication,this paper designs a slow start rate control scheme based on the slow start algorithm used in TCP congestion control.The scheme makes it possible to change the video rate according to real-time net speed.It is proved that this scheme will reduce the packet loss rate cause by the change of net speed.The performance of the scheme is completely dependent on the transmission threshold.In the case of inaccurate threshold settings,video communication will generate periodic packet loss.In order to solve this problem,this paper designs an adaptive rate threshold scheme based on the cyclic queue principle.This scheme will automatically try to adjust the bit rate threshold to achieve the best communication experience for Vo IP video communication while video communication.Experiments show that the method can adjust the video bit rate to the optimal value after communication for a period of time,avoiding periodic packet loss.