基于SIP的MCU视频会议系统的实现

目前的MCU视频会议主要基于H323标准,适合在专用网内进行部署。设计一种基于SIP的MCU视频会议系统,该系统在软交换网关和MCU分别进行H323和SIP信令互换;呼叫处理部分用标准的SIP信令来实现,业务逻辑用以SIP应用服务器控制,应用服务器与Web服务器间用TCP/IP通信,将会议的媒体处理单元(MCU)、终端、资源管理器、Web服务器有机的结合在一起。     

浅谈DVB—C系统在数字电视中的应用

根据DVB—C的原理,提出基于DVB—C的数字电视系统实现方法。阐述DVB前端、条件接收系统（CAS）的加密体系、电子节目指南（EPG）系统方案、宽带传输网络、用户终端DVB接收系统等技术原理和系统组成。同时对DVB-C系统技术方案进行一些技术探讨和总结。     

视频点播在网络应用中的问题及对策

通过对视频点播系统概念、原理、组成、功能和应用现状的介绍,分析了视频点播系统在实际应用中的前景及其存在的问题,并提出了解决问题的建议。     

用VB编写Windows XP系统的娱乐游戏类附件工具

介绍如何用最少的VB代码,自制WindowsXP系统的娱乐游戏类附件工具。     

From MPEG-7 user interaction tools to hanging basket models: bridging the gap

The content–user gap is the difference between the limited range of content-relevant preferences that may be expressed using the MPEG-7 user interaction tools and the much wider range of metadata that may be represented using the MPEG-7 content tools. One approach for closing this gap is to make the user and content metadata isomorphic by using the existing MPEG-7 content tools to represent user (as well as content) metadata (Agius and Angelides 2006, 2007). Subsequently, user preferences may be specified for all content, without omission. Since there is a wealth of user preference and history metadata within the MPEG-7 user interaction tools that can usefully complement these specific content preferences, in this paper we develop a method by which all user and content metadata may be bridged.

A fast SVD based video watermarking algorithm compatible with MPEG2 Standard

This paper presents a real time video watermarking algorithm based on the singular value decomposition (SVD). The embedding procedure combines the DCT and SVD. The SVD is applied on the low frequency AC coefficients of block DCT of the frame. Then the relation of neighbor coefficients of those middle frequency bands in the singular values is modified. The hidden information can be extracted without the original video or the order of the original singular values, i.e., this is a blind watermarking algorithm. Experiments show that the algorithm is very robust against MPEG-2 compression, median filtering, small shift, and rotation, etc.     

Mediating Power: Distance Learning Interfaces, Classroom Epistemology, and the Gaze

Distance learning's interfaces—from corresponding through the postal service to the televised talking head—have traditionally been designed from the top down, supporting banking models of learning or, in writing instruction, current-traditional rhetoric pedagogies. Due to temporal and spatial constraints, these interface designs often support (or encourage) one-way communication from the instructor to the student. Students mostly interact with the instructor by asking questions or submitting work, and they tend to have little correspondence with other peers. These methods clearly privilege the instructor's knowledge and evaluation. Furthermore, these interface designs empower the instructor to gaze upon the students and assess them—often not as a corporeal body but as a corpus of texts. Thus, each interface adopted for distance learning sets up a power dynamic in which the capability to share the roles of creating knowledge is juxtaposed with the instructor's capability to normalize the students and reify their own authority through their gaze. In this article we examine the traditional classroom interface through the correspondence course interface, the simulated classroom interface, and the synchronous video interface to raise questions about the infrastructures of distance learning and their implications for student learning.     

基于P2P的流媒体点播技术研究与展望

视频点播数据传输的离散程度,给P2P流媒体点播技术带来了极大的挑战.分析了P2P流媒体点播技术的基本问题,从媒体资源定位和分发两个方面介绍各种已提出的协议和算法,结合P2P视频点播的特点和网络应用的实际需求分析其优点和不足,并以此为基础提出有待解决的主要问题,为进一步的研究和应用提供有益的参考.     

基于嵌入式浏览器的交互式IPTV

交互式IPTV的核心服务之一是视频点播服务(Video On Demand)。IPTV的系统基于IP网络,这一特点有助于设计更好的VOD交互模型。提出了一种使用嵌入式浏览器作为VOD点播终端的新设计方法。     

基于C#的网络视频分发策略的研究

网络分发策略对于视频应用的服务质量起着至关重要的作用。本文在分析现有分发策略的基础上,提出了基于启发式视频媒体数据分发策略的思想,并给出了基于C#平台的启发式分发策略的算法描述。