In this paper , three method are proposed . the two among them are that the higher information transmission data rate will be given in the increasement of the signal transmitted power , and another is got through the compression of video signal data rate 論文提出了三種方法,即兩種通過信號功率增加使信息傳輸速率提高的方法和一種壓縮視頻帶寬提高數(shù)據(jù)傳輸速率的方法。
Firstly , the paper compares v . 90 , modem , xdsl , isdn in their characters , difficulties , management and costs . finally , we choose to construct the h . 320 multi - media communication system based on n - isdn . secondly , in the theoretical part of the paper , the basic theory of h . 320 multi - media communication is introduced , such as the compression of video and audio data , h . 320 stack protocol and especially introduced the theory , relative protocol and the technique of access to the net of n - isdn 本文針對銅線接入技術應用的基礎和現(xiàn)狀,對v . 90 、 modem 、 xdsl 、 isdn等接入方式的技術特點、接入難度、運行管理和經(jīng)濟性等方面進行對比分析,結(jié)合接入的具體環(huán)境,通信需求和經(jīng)濟性等方面的特點,重點闡述了n ? isdn接入方案的可行性和“基于n ? isdn接入的h . 320多媒體通信系統(tǒng)”的實現(xiàn)方案。
This paper also provides some background knowledge about sip and video conference , such as the sip framework , the history of voip and video conference , etc . this paper emphasizes on the implementation of sip terminal on the windows platform , including the realization of sip stack , the capture and compression of video and audio steams , rtp transmission of stream data , the working thread of sip terminal and the optimization of video codecs 本文在論述研究工作的同時也介紹了一些相關的背景知識如sip協(xié)議的框架、 voip和可視電話的發(fā)展歷史等。本文重點論述了windows平臺sip多媒體終端的實現(xiàn),包括sip協(xié)議棧的實現(xiàn)、視音頻流的采集、編解碼和網(wǎng)絡傳輸方案、 sip終端的工作流程、以及編解碼器基于指令集的優(yōu)化。