مرکز منطقه ای اطلاع رساني علوم و فناوري - A Simple and Effective Audio Compression Application For Voice Over Internet Protocol Applications By Using Discrete Wavelet Transform

Abstract :

In recent years, computer networks and Internet have become widespread quickly, and as a result of this, new applications have started to emerge. The transmission of voice, video and images over computer networks and Internet has brought cost advantages over traditional methods [1]. The most important point in this kind of services over Internet is end-to-end transmission time. According to ITU G.114 standard, for carrying voice, end-to-end delay is to be 0 to 150 ms [2]. A quality of service system that keeps end-to-end delay under control in VOIP technology which means carrying voice over Internet protocol is required for a quality service [3]. But a quality of service application alone that provides guaranteed bandwidth and priority to specific services is not sufficient. Usually voice is compressed by the use of compression algorithms and then carried, to make it occupy less space. This paper presents a simple and effective lossless audio compression using discrete wavelet transform with an optimal global threshold for voice over IP applications. The method used in the application performs a simple and fast compression and satisfies the requirements of VOIP applications. The application performs voice compression quickly without requiring much processing power, and satisfactory audio quality and high compression rates are obtained. This method is suitable for routers and VOIP gateways which perform voice compression.