一直以来,网络上的交流一直是以文字的方式进行,不过随着网络接入技术的发展,ADSL、小区宽带等高速网络接入技术把我们带入了宽带网络时代。同时,伴随着多媒体技术特别是视、音频信息的编码压缩和流式传输技术的成熟,语音和视频开始在网络上广泛传输。另外一方面,随着计算机制 All along, the exchange on the Internet has been carried out by means of text, but with the development of network access technology, ADSL, residential broadband and other high-speed network access technology brought us into the era of broadband networks. At the same time, along with the maturation of multimedia technologies, especially video and audio coding, and streaming technologies, voice and video are beginning to be widely transmitted over the Internet. On the other hand, with the computer system