Research On Some Issues Of Quality Assurance Of Audio And Video Communication In Android Terminal

In recent years,the Internet has developed rapidly,and the applicable scope of VoIP technology has become more and more widespread.Using intelligent terminals,people can communicate by means of audio and video conveniently.The Android system has the highest occupancy rate in intelligent terminals,and its audio and video communication applications are various.While people's demand on them is increaseingly high,how to ensure the quality of audio and video communication of Android terminals is highly valued.Echo has always been a key factor affecting communication quality.The echo in network audio and video communication is acoustic echo.It means that the far-end signal is collected by the microphone after being played out,and then transmitted back through the Internet,causing the remote user to hear his voice,which depair the user's satisfaction greatly.It's vital to implement echo cancellation.Video streaming media content occupies a large bandwidth,which is easily affected by network fluctuations,causing halting video or mosaic.Although UDP is generally used to transmit real-time media data packets,it doesn't provide any quality guarantee.Therefore,the solution of network transmission problem of video stream is also highlighted on the quality assurance of audio and video communication.Focusing on the above two issues,this thesis proposes the following solutions:(1)In terms of audio,with the theory of echo cancellation,the implementation of WebRTC_AECM echo cancellation algorithm is analyzed,and the basic scheme of echo cancellation is determined.In addition,audio processing delay on Android terminals is extremely various,which affects the effect of echo cancellation.So the echo delay estimation scheme is proposed,and the accuracy is verified in real tests on Android Terminals.The experimental results show that the combination of WebRTC_AECM and the echo delay estimation scheme of this thesis can eliminate the echo in the terminal communication more quickly,which guarantees the quality of audio communication.(2)For the video stream,this thesis puts forward a complete network state partitioning algorithm.Based on this,the adaptive rate control algorithm on the source is proposed,including the rate adjustment algorithm and the frame filtering compensation algorithm.Finally,the audio and video communication platform based on Android terminal is built.With a lot of tests,the rationality and feasibility of the algorithm scheme are analyzed.The experimental results show that the adaptive rate control algorithm on the source proposed in this thesis can reduce the packet loss rate,improve the bandwidth utilization and provide gurantee for video real-time transmission,which has practical value and reference significance.