多媒体CAI课件制作中的数字视频处理技术

在多媒体CAI课件中，视频是一种重要的多媒体元素。利用数字视频技术对视频材料进行编辑制作和加工处理，是多媒体课件开发中的重要一环。该文探讨了数字视频技术在多媒体CAI课件制作中的应用，着重从数字视频处理硬件技术、数字视频采集与压缩、数字视频编辑三方面进行了阐述。     

Multimedia networks: issues and challenges

Video on demand, teleconferencing, digital libraries, and remote tutoring systems are just a few of the many distributed multimedia applications that have emerged in recent years. Widespread use of such applications requires networks that can offer transport services to both discrete media (such as text and digital images) and continuous media (such as audio and video). The discussion explores some of the issues involved in the design of such networks     

Data compression in multimedia computing — principles and techniques

Integrated multimedia systems process text, graphics, and other discrete media as well as digital audio, and video data. Considerable amounts of graphics, audio and video data in their uncompressed form, especially moving pictures, require storage and digital network capacities that will not be available in the near future. Nevertheless, local, as well as networked, multimedia applications and systems have become realities. In order to cope with these storage and communication requirements in such integrated multimedia systems, compression technology is essential. This papers starts with a brief motivation of the need for compression and subsequently states the essential requirements for these techniques in the scope of multimedia systems and applications. As most of these techniques apply the same principles, namely, the source, entropy, and hybrid coding fundamentals, these are explained in detail. Based on a general framework of the steps encountered in a compression system — data preparation, processing, quantization, and entropy coding — this paper outlines details about the techniques developed by CCITT (H.261, i.e., px64), in the ISO/IEC (JPEG, MPEG) standardization bodies and the proprietary DVI system.     

基于EM8620L的嵌入式多媒体播放终端设计

采用专用多媒体视音频解码芯片EM8620L为核心，设计了一种新型的多媒体播放终端，它能够播放多种格式的多媒体文件。其硬件主要由专用解码芯片、网络控制电路、存储器和显示控制电路组成，软件系统由操作系统、图形系统和应用程序组成。通过调试证明该方案合理、先进，为视频联网广告系统提供了一种功能强大的、智能化的播放终端。     

A quality-of-service specification for multimedia presentations

The bandwidth limitations of multimedia systems force trade-offs between presentation-data fidelity and real-time performance. For example, digital video is commonly encoded with lossy compression to reduce bandwidth, and frames may be skipped during playback to maintain synchronization. These trade-offs depend on device performance and physical data representations that are hidden by a database system. If a multimedia database is to support digital video and other continuous media data types, we argue that the database should provide a quality-of-service (QOS) interface to allow application control of presentation timing and information-loss trade-offs. This paper proposes a data model for continuous media that preserves device and physical data independence. We show how to define formal QOS constraints from a specification of ideal presentation outputs. Our definition enables meaningful requests for endto-end service guarantees, while leaving the database system free to optimize resource management. We propose one set of QOS parameters that constitute a complete model for presentation error, and we show how this error model extends the opportunities for resource optimization.     

基于多模态子空间相关性传递的视频语义挖掘

在视频语义信息理解和挖掘中,充分利用图像、音频和文本等多模态媒质之间的交互关联是非常重要的研究方向.考虑到视频的多模态和时序关联共生特性,提出了一种基于多模态子空间相关性传递的语义概念检测方法来挖掘视频的语义信息.该方法对所提取视频镜头的多模态底层特征,根据共生数据嵌入(co-occurrence data embedding)和相似度融合(SimFusion)进行多模态子空间相关性传递而得到镜头之间的相似度关系,接着通过局部不变投影(locality preserving projections)对原始数据进行降维以获得低维语义空间内的坐标,再利用标注信息训练分类模型,从而可对训练集外的测试数据进行语义概念检测,实现视频语义信息挖掘.实验表明该方法有较高的准确率.     

基于IP网络的多媒体视频通信技术研究

本文首先简要阐述了多媒体通信的概念和主要形式和发展概况,之后对基于IP网络的多媒体视频通信[1]的组成进行了介绍;对对多媒体视频通信技术的Java[2]媒体播放架构（JMF）和R．TP协议的关键技术进行了详细的分析。最后通过对系统服务器和客户端以及实时数据传输的功能性设计,从而实现了采用JMF平台和RTP协议的多媒体视频通信系统。     

计算机多媒体技术的应用研究

计算机多媒体技术,就是通过计算机将文字、图像、视频、声音、动画等多种形式的媒体信息都经过一系列的变换,转变成为数字信息,同时,把这些数字信息通过友好的界面进行显示出来。计算机多媒体技术的应用正在日趋广泛,结合笔者的实际工作经验,主要从多媒体教学方面探讨了计算机多媒体技术的应用。     

Hardware assisted watermarking for multimedia

Digital media offer several distinct advantages over analog media, such as high quality, ease of editing, and ease of processing operations such as compression and high fidelity copying. Digital data is commonly available through digital TV broadcast, CD, DVD, and computing devices such as personal computers. The ease by which a digital media object can be duplicated and distributed has led to the need for effective digital rights management tools. Digital watermarking is one such tool. Watermarking is the process of embedding extra data called a watermark into a multimedia object, like image, audio, or video, such that the watermark can later be detected or extracted in order to make an assertion regarding the object. During the last decade, numerous software based watermarking schemes have appeared in the literature and watermarking research has attained a certain degree of maturity. But hardware based watermarking systems have evolved more recently only and they are still at their infancy. The goal of hardware assisted watermarking is to achieve low power usage, real-time performance, reliability, and ease of integration with existing consumer electronic devices. In this paper, we survey the hardware assisted solutions proposed in the literature for watermarking of multimedia objects. The survey is preceded by an introduction to the background issues involved in digital watermarking.     

Scheduling multimedia presentations in educational digital libraries

An educational digital library is a specialized digital library containing instructional materials, such as class lectures, seminar presentations, and various training materials. These materials consist of a combination of audio, video, and image data. In such an environment, basic parts of multimedia data are usually stored in databases and sophisticated multimedia presentations may be assembled to generate various presentations. In this paper, we investigate a theory of the scheduling strategies for supporting the synchronized presentations of multimedia streams which is applicable to educational digital libraries. This scheduling theory includes the specification and representation of synchronization on media streams, the realization of appropriate synchronization granularity, and the scheduling principles for the presentations of multimedia streams. This investigation formulates criteria for specifying and scheduling the skipping/pausing of media streams with asynchronous presentations when various delays occur. Adaptability to various quality-of-service requirements is supported in the scheduling strategies. Various synchronization mechanisms at both client and server sides are proposed to implement the scheduling theory. Experimental analysis is conducted using instructional materials.     

多媒体中的数字水印技术

随着计算机网络技术的飞速发展,数字多媒体例如:图像、音频、视频以及文本文件在人类生活中的应用越来越广泛。由于数字媒体不仅容易在网络中传播,也容易被人非法复制、篡改。近十几年来,为了保护数字多媒体,数字水印技术慢慢发展起来。本文重点阐述了数字水印概念、特征以及基本原理,并对数字水印对多媒体的保护作用、发展现状和前景等方面进行了深入研究和探讨。     

MPEG的新发展——多媒体框架标准MPEG-21

标准化是产业化活动成功的前提，视、音频编码的各种国际标准的制定集中地反映了视、音频编码技术发展的水平．目前，图象压缩方面的标准主要有MPEG系列(MPEG-1，MPEG-2，MPEG-4，MPEG-7和MPEG-21标准)，以及H．26X系列(H．261，H．263标准)和静止图象压缩标准JPEG．为了使人们对图象压缩标准有所了解，以进一步推动图象压缩方面的研究，首先对MPEG系列的各种已有标准及其应用进行了概述，然后着重讨论了MPEG中的新面孔——正在开发的MPEG-21标准，并就其目标、用户需求、技术要素、关键任务、应用领域以及工作计划做了较详细的描述．     

Bringing Commercial Games into the Classroom

One of the challenges facing us when we try to bring commercial materials such as video games into the classroom to be used as educational tools is to identify appropriate strategies of collaboration with teachers, families, and even industries. This paper explores how multimedia contexts can be created in which children become active participants in a digital universe where multiple technologies are present (so that video games are just one of several digital tools). We present several examples derived from specific projects carried out in formal and informal educational contexts, in action research and from ethnographical perspectives. As participant observers in and outside the classroom, we designed workshops as innovative educational contexts; all the sessions were video and audio recorded. Our analysis adopted a socio-cultural perspective. Several preliminary results clearly appeared: (a) Children playing commercial games inside and outside classrooms produce different writing texts depending of the context in which they are generated; (b) using video games combined with other digital technologies seems to be an effective way of introducing children to the content and structure of games considered as dynamic systems; (c) using and reflecting on video games in and outside the school, via discussions in digital media such as blogs or pictures, can contribute to the development of digital literacies as a way of using multimodal discourses. Our main goal at this moment is to design digital materials capable of supporting teachers’ and families’ use of games and in particular, to reveal the rules that organize their structure, codes and symbolic universe.     

Synchronization-Oriented Placement and Retrieval Strategies for Delay-Sensitive Media Streams

Multimedia data include text,image,audio and video,etc.Recent developments and advances in the areas of mass storage technology and high speed networks make it feasible for multimedia computing systems to offer services such as multimedia e-mial,teleconferencing and various vivid games.The storage and retrieval of multimedia data are two of the most important technologies in the futre multimedia systems.This paper analyzes the synchronization requirements of the delay-sensitive media streams,classifies the synchronization hierarchically and proposes several effective strategies for the intra-media and inter-media data placement problems.     

MPEG-2视频解码器在DirectShow中的实现

MPEG-2是目前应用最为广泛的数字音视频编码国际标准,大部分数字音视频节目是以MPEG-2的形式存在.DirectShow是目前windows操作系统上的优秀的多媒体开发编程接口.提出一个MPEG-2视频解码器在DirectShow中的实现方案.这一实现在多媒体应用中具有广泛的参考价值.     

A spatio-temporal semantic model for multimedia database systemsand multimedia information systems

As more information sources become available in multimedia systems, the development of abstract semantic models for video, audio, text, and image data is becoming very important. An abstract semantic model has two requirements: it should be rich enough to provide a friendly interface of multimedia presentation synchronization schedules to the users and it should be a good programming data structure for implementation in order to control multimedia playback. An abstract semantic model based on an augmented transition network (ATN) is presented. The inputs for ATNs are modeled by multimedia input strings. Multimedia input strings provide an efficient means for iconic indexing of the temporal/spatial relations of media streams and semantic objects. An ATN and its subnetworks are used to represent the appearing sequence of media streams and semantic objects. The arc label is a substring of a multimedia input string. In this design, a presentation is driven by a multimedia input string. Each subnetwork has its own multimedia input string. Database queries relative to text, image, and video can be answered via substring matching at subnetworks. Multimedia browsing allows users the flexibility to select any part of the presentation they prefer to see. This means that the ATN and its subnetworks can be included in multimedia database systems which are controlled by a database management system (DBMS). User interactions and loops are also provided in an ATN. Therefore, ATNs provide three major capabilities: multimedia presentations, temporal/spatial multimedia database searching, and multimedia browsing     

Usage derived recommendations for a video digital library

We describe a minimalist methodology to develop usage-based recommender systems for multimedia digital libraries. A prototype recommender system based on this strategy was implemented for the Open Video Project, a digital library of videos that are freely available for download. Sequential patterns of video retrievals are extracted from the project's web download logs and analyzed to generate a network of video relationships. A spreading activation algorithm locates video recommendations by searching for associative paths connecting query-related videos. We evaluate the performance of the resulting system relative to an item-based collaborative filtering technique operating on user profiles extracted from the same log data.     

Efficient PCIe transmission for Multi-Channel video using dynamic splicing and conditional prefetching

Multimedia Tools and Applications - PCI Express (PCIe) interface has been extensively used in high-speed digital systems for multimedia communication. With the migration of the video processing...     

基于iebook的电子书播放外部视频功能的实现

Exe类型电子书制作软件集成文字内容和小图片非常容易,效果也很不错,但是对集成高品质的音视频、数码照片等大容量数据文件却无能为力。通过对iebook超级精灵自带模板以及Exe电子书文件的深入分析,把flash技术、流媒体对象和file协议有机结合,实现动态加载指定相对路径下的外部视频文件到电子书中,大大提高了iebook超级精灵在处理多媒体方面的实用性。     

An analytical framework for event mining in video data

With the high availability of digital video contents on the internet, users need more assistance to access digital videos. Various researches have been done about video summarization and semantic video analysis to help to satisfy these needs. These works are developing condensed versions of a full length video stream through the identification of the most important and pertinent content within the stream. Most of the existing works in these areas are mainly focused on event mining. Event mining from video streams improves the accessibility and reusability of large media collections, and it has been an active area of research with notable recent progress. Event mining includes a wide range of multimedia domains such as surveillance, meetings, broadcast, news, sports, documentary, and films, as well as personal and online media collections. Due to the variety and plenty of Event mining techniques, in this paper we suggest an analytical framework to classify event mining techniques and to evaluate them based on important functional measures. This framework could lead to empirical and technical comparison of event mining methods and development of more efficient structures at future.