节点文献
视频会议系统MCU的研究
The Research of MCU in Video Conference System
【作者】 杨刚；
【作者基本信息】 北京邮电大学 ， 检测技术与自动化装置， 2011， 硕士
【摘要】 随着科学技术的不断发展,传统的视频会议已经不能满足人们的要求,高清视频会议系统已经成为主流。多点控制单元(MCU)是视频会议系统中的重要控制部件,其性能优劣直接影响视频会议系统的质量。针对视频会议系统的MCU,本文研究了国内外视频会议系统的发展现状,就当前研究热点做了分析,介绍了MCU的主要功能。作者对视频会议系统中用到的音视频编解码做了详细研究,具体测试了开源音视频编解码库G.711、G.729、H.261、H.263和H.264,对编解码前后的音频信号波形变化和视频图像大小及质量分别做了对比分析。文章还介绍了H.323协议栈,对该协议栈的各个组成部分和信令做了详细的分析。研究了基于H.323的MCU的基本结构,对软件MCU和硬件MCU做了对比分析,给出了软件MCU的系统管理功能做了需求分析。根据VIS H.323 DLL Library提供的API函数研究并设计了一个小型的视频会议系统的MCU,实现了音视频转发和会议控制,设计了基于TCP/IP协议在线文字讨论模块,最后提出了一种新的基于VLC的ActiveX控件的分屏显示方法。使用MFC实现了MCU的界面设计。论文最后对实现的MCU系统功能进行了测试,就视频会议系统多点控制单元的发展进行了总结和展望。论文所研究的内容来源于实际视频会议项目,具有一定的实用价值。
【Abstract】 With the development of science and technology, the traditional video conference can not meet people’s demands,high-definition video conference systems have become mainstream. Multi-point Control Unit(MCU) is an important control component in video conference, Its performance directly influences the quality of the video conference.For the MCU of video conference system, this paper studies the development status of the video conference system of domestic and international, and to do analysis of the current research focus, and introduce MCU’s main features. Author do a detailed study on audio and video codecs used in video conference system, and do a specific test for open source library about the H.261, H.263, H.264,G.711,G.729codec, compare the change of audio signal waves and the video image’s size and quality after encoding and decoding. The article also describes the H.323 protocol stack, and give a detailed description about the stack of the various components and signaling. It study the basic structure of MCU based on H.323,and do a comparative analysis software MCU and hardware MCU, and do a software requirements analysis of software MCU systems management capabilities. This paper research and design a simple MCU according to VIS H.323 DLL Library provided API functions, achieve the audio and video forwarding and conference control, and detailed design the online text discussion modules based on the TCP/IP protocol. Finally, propose a new method about the split screen based on VLC’s ActiveX controls. Achieve the interface design of MCU with MFC.At the end of the paper, author test the system function of realized MCU, and do a summary and outlook for the development of MCU. The contents of the studied items from the actual Project of video conference, has some practical value.