Development And Implementation Of Echo Cancellation Algorithm Based On WebRTC In VoIP Telephone

With the development of network bandwidth, VoIP technology and its applications are developing rapidly. Compared with traditional call, IP (Internet Protocol) call has high network bandwidth utilization, low-cost, and the flexibility to provide many value-added features, so it is getting more and more support from the market. However, during the VoIP call, the echo is very grave, which do serious impact on call quality and user experience. Therefore, in order to make VoIP widely used, we must raise its voice quality, that is to say we must eliminate the echo introduced by the transmission process through the Internet.This paper has deeply analysed the AEC (Acoustic Echo Cancellation) algorithm of the open source WebRTC project, and focused on its working performance on embedded mobile devices. The architecture of WebRTC AEC algorithm, its workflow and each module’s function call process were described in detail in the paper. The open source software linphone was selected as the VoIP application and its architecture were discussed in detail in the paper. The widely used Android operating system was selected as the software platform. The TI’s DM6446which has very powerful media capabilities was selected as the hardware platform. Then this paper described in detail how to port the AEC algorithm to the linphone application and how to download the images compiled in the android source codes tree to the DM6466hardware platform to test the working performance of the AEC algorithm. Three groups of test cases were designed, each represent an application scenario and each was repeat several times. Through analyse the waveforms processed by the AEC algorithm and feedback of persons who have listened the actual voices, we can conclude that the AEC algorithm has very well echo cancellation performance and can be applied to VoIP applications of embedded devices.