【作者】 路强；

【导师】 韩江洪；

【作者基本信息】 合肥工业大学 ， 计算机应用技术， 2004， 硕士

【摘要】 计算机网络和多媒体技术的发展，尤其是近几年基于TCP／IP的宽带网络的迅速发展和普及，基于IP网络的多媒体应用--MoIP(Multimedia over IP)成为一个备受关注的领域。社区宽带网的发展使得日常生活的各项服务逐渐网络化，因而出现了对社区宽带网上特色业务的需求，各种社区网络可视化服务的无疑应放在重要位置。本论文在智能家居系统课题中针对视频编码、传输技术研究的基础上，对社区宽带网络多媒体应用进行研究。 国际电信联盟(ITU-T)制定的H．323建议，定义了终端等实体在不假定提供服务质量保证的基于分组的网络上提供多媒体通信服务。H．323实体可以提供实时的音频、视频和／或数据通信。H．323实体可以被用于各种网络的配置，如点对点、点对多点等。 结合社区宽带网络环境和多媒体应用的需要，将H．323建议运用到社区宽带网络多媒体应用中成为一种可行并且可靠的方案。本文对H．323建议进行了深入的分析，并在此基础上提出了社区宽带网络多媒体应用的结构、多点通信过程、控制系统等内容的实现方案。 网络多媒体通信过程中多点控制器是十分重要的功能实体。多点控制器的主要功能之一是对来自各个与会者的视频流进行处理与转发。本文提出了一种改进的基于MPEG-4的转编码方案，该方案充分利用网络带宽提供更高的视觉效果、并且降低了多点控制器的运算负担。 MPEG-4技术的发展成熟，迅速成为多媒体研究与应用的热点。MPEG-4和传统的MPEG-1、MPEG-2和H．323协议框架中的视频部分H．263压缩标准相比，在存储容量、图像质量、网络传输、抗误码性等方面都具有巨大的优势。因此，本方案采用MPEG-4作为视频压缩标准。 本文提出并实现了运用于转编码方案中的MPEG-4改进编码算法。通过实验数据验证了该算法比MPEG-4的Q2码率控制方案有更好的效果。更多还原

【Abstract】 As the quick development of computer networks and multimedia technology and the popularization of broadband networks based on TCP/IP in recent years, MoIP (Multimedia over IP), which is a multimedia application based on IP networks, becomes a concentrated research area. The development of Residential Broad Band (RBB) enables various daily services to be used on the Internet, which also asks for specialized services on the RBB and the key position of visualized services of RBB. Based on the research of video coding and transmission techniques of Smart Home System, this dissertation carries on the research work of network multimedia application of RBB.The H.323 proposal made by ITU-T defines the way to offer multimedia communication services of terminal peers without an assumption of QoS on package networks. H.322 entity can provide real-time sound, video and/or data communication and can be used to configure various networks, such as point-to-point, point-to-multipoint networks.With the requirement of RBB environment and multimedia applications, it has become a feasible and reliable scheme to apply H.323 proposal into multimedia application of RBB. This dissertation delves into H.323 proposal and based on that detailed analysis, it put forward a method to realize the architecture of multimedia application of RBB, multipoint communication process and control system.As the maturing of MPEG-4, it has become a concentrated research area of multimedia application. Comparing with the traditional video compression standard in MPEG-1 and MPEG-2’s framework, MPEG-4 has great advantages in storage volume, quality of graph, net transmission, and error resistance. So, this project uses MPEG-4 as the video compression standard.Multipoint controller is a key functional entity in network multimedia transmission process. One of the main functions of multipoint controller is to process and redistribute the video stream coming from every participant. This dissertation proposes an improved encoding scheme of MPEG-4. It utilizes network bandwidth to provide an enhanced visualization and reduces the computation workload of multipoint controller.This dissertation proposes and realizes the enhanced coding algorithm of MPEG-4 that could be applied to transcoding scheme. Furthermore, it validates the expected results with the experimental data and shows the better effect for transmission of rate-control scheme when comparing with the Q2 in MPEG-4.更多还原