Research Speech Coding Technology Base On VOIP System

Internet technology has revolutionized the way of people’s life. Voice over internet has rapidly developed in the 4G era, mobile client use Wechat, QQ and other APP to transmit voice through the Internet. With rapid development of Multimedia services, frequency resources become more and more valuable, voice service consumes more and more data traffic, therefore compressed coding is needed. Compression coding technology determines the future of VOIP system communication.Voice over internet has not been widely used, the main reason is that the instability of voice quality cannot satisfy the requirements of long-distance call. In order to improve the quality of synthetic speech, this paper use G.729 coding standards instead of G.711 coding standards in the internet. Firstly, mechanism of voice production and the corresponding mathematical model is provided by our research, we use stationary random process to study the linear prediction model of G.729 coding standards based on characteristics of the short speech stability, we use autoregressive moving average model to replace autoregressive model to estimates the parameters of voice, theoretical analysis and experimental simulation are used to calculate both models’power spectrum, theoretical analysis and experimental results demonstrate that autoregressive moving average model can further improve the quality of synthetic speech; Secondly, we use moving average model to construct autoregressive moving average model in the G.729 standard linear prediction module; Finally, MATLAB is used as our experimental platform, simulation interface of G.729 coding standard is designed through combing GUI with M-file, we also complete simulation experiments of voice codec of two models, compare waveforms and analysis the results.As a new industry, voice of internet is at a critical point of introduction and growing period, G.729 coding standards cost highly due to the impact of network environments and speech coding technology, therefore it’s application in voice over internet is limited. However, with the development of coding technology, G.729 coding standards will play an important role in the voice over internet system by its own advantage. This paper has a high practical value in the study of voice coding technology in VOIP system.