On-line broadcast archives for interactive video

Delivery of user specified interactive multimedia digital services is drawing worldwide attention. With the availability of a greater number of channels as a result of video compression and the receding geographical barriers, content providers are hard pressed to meet the programme requirements. Broadcast archives are valuable multimedia resource centres, stocking audio and video material of interest to a vast population across the globe. There is a great potential for using these archives for on-line interactive access of these material. The paper describes the system architecture and implementation issues of an on-line broadcast archives management system (OLBAMS) which entails various functions of storage and dissemination, taking advantage of emerging digital technology, viz. video servers, OODBMS, CORBA, MPI video, use of Java applets for set-tops, webTV, or computers     

适用于广播监视的安全视频水印方案

考虑到广播监视应用中对视频片段的认证问题,基于三维离散小波变换,提出一种新颖的顽健视频散列算法,并利用生成的散列值和水印标识形成待嵌入的水印信息,以实现对视频片段的认证.在此基础上利用扩频水印技术提出一种适用于广播监视的安全、顽健的视频水印算法.理论分析和实验结果表明,提出的算法具有很好的安全性和顽健性.     

基于可见光通信的一对多视频广播系统

利用自主研发的软硬件搭建了基于可见光通信(VLC )的一对多视频广播系统。通过传输流(TS,transport stream)音视频数据流解决了通信信道 不可靠的问题,通过广播流量控制算法和控制指令的设计解决了多媒体数据广播传输时服务 器和客户端速率不匹配带来的超大缓存需求问题。可见光收发模块采用荧光型LED和PIN探测 器作为光源和探测器。系统拥有蜂窝网络结构,每个蜂窝可以有多个用户,客户可以同时接 收广播信号且不会相互干扰。通过实验实验证了系统的可行性。测试结果表明,本文系统支 持1对多的1080P视频数据光学无线广播传输,每个用户的接收带宽为 2Mbit/s,传输距离为2m。     

A GACS modeling approach for MPEG broadcast video

Accurate MPEG source models are needed to support high speed networks such as ATM and Internet. In this paper, we propose a video model called Gaussian auto-regressive and chi-square processes (GACS) for MPEG coded video traffic. The GACS models the sizes of MPEG I, P, and B frames according to the MPEG syntax I-frame>P-frame>B-frame. This is done by decomposing the process of each frame size into a weighted sum of a number of chi-square sequences. Each chi-square sequence is then obtained by squaring a Gaussian process, which is efficiently generated by using an auto-regressive (AR) model whose parameters are determined from an estimated covariance matrix. We evaluate the effectiveness of our model by conducting a series of experiments using a wide variety of long empirical video sequences. The results show that the proposed model leads to excellent data fit and accurate prediction of queuing performance.     

一种基于Helix服务器的网络视频直播的实现

随着宽带用户的迅速增长,网络视频技术得到更多的应用。现论述了网络视频直播的工作原理和系统构成,给出了一个基于RealHelix服务器的网络视频直播系统在企业边界网中的实现,特别说明了在具体应用中应注意的若干问题。     

基于3G网络的视频直播传输系统方案设计

实现了标清视频通过3G网络进行直播传输,针对3G网络现状上行速率不足的问题,采用多信道绑定和信道均衡预处理技术,提出系统的解决方案,并给出了系统发送端设备的硬件和软件的实现方案,最后给出样机的测试和试用情况,结果显示该方案的有效性.     

P2broadcast: a hierarchical clustering live video streaming system for P2P networks

This work describes a novel live video streaming system for P2P networks, referred to as P2broadcast. The video streaming service has bandwidth requirements to guarantee presentation quality. Therefore, a scalable strategy to quickly find a path from a media server to a client with abundant bandwidth is very important. A common approach in the literature is the bandwidth first (BF) scheme, which allows a newcomer to adopt a BF tree traversal scheme to find its parent peer on the P2P overlay tree to retrieve the media content. The BF scheme is likely to build a deep overlay tree, resulting in long start‐up latency as the number of peers on the overlay tree grows. P2broadcast reduces start‐up latency by organizing peers into hierarchical clusters and making the overlay tree become a ‘short‐and‐wide’ tree. The hierarchical clustering structure enables a newcomer to find its parent peer among the set of peers that are more likely to provide large available bandwidth only. Limiting the set of potential parent peers not only reduces start‐up latency but also improves the system availability. Additionally, unlike the BF scheme that only concerns available bandwidth, P2broadcast utilizes a cost function to evaluate the appropriateness of a potential parent peer. The cost function considers the depth of the newcomer on the overlay tree, making the overlay tree become a short‐and‐wide tree. In addition to start‐up latency reduction, the short‐and‐wide tree feature also alleviates the service interruption probability due to the leaving or failure of a peer. Our simulation results show that P2broadcast greatly outperforms the BF scheme in terms of system availability, and achieves around 66% savings in start‐up latency and 10% decrement in service interruption probability. Copyright © 2005 John Wiley & Sons, Ltd.     

广播新闻语音的关键词检测系统

提出了一种两阶段的关键词检测策略，关键词表可即时配置、即时使用。与以往不同的是，解码是在整个声学空间上进行的，而不仅仅是关键词所构成的声学空间。首先，利用维特比解码得到最优候选的音素序列。然后，通过关键词列表，可以产生候选的关键词。最后，采用了基于声学模型的置信度与基于网格的置信度相结合的方法来降低虚警。实验证明，新的框架下关键词检测的性能得到了显著的提高。     

Interactive broadcast services for live soccer video based on instant semantics acquisition

This paper presents a system for providing interactive broadcast services for live soccer video that is based on instant semantics acquisition. Currently, we have implemented two such interactive services: live event alert and on-the-fly language selection. The live event alert service has a small time lag of about 30 s for a short video clip to reach its final viewer and at most 1.5 min for a long clip of the live event. The on-the-fly language selection service allows users to choose their preferred contents and preferred language. The motivation for this work is that such interactive services will greatly increase the value of live soccer video. Currently, similar systems attempt to derive semantics of a soccer game from gamelog in freestyle text format and low-level features of the video, which is a challenging task. In this paper, we tackle this challenge with a combination of both gamelog input tool and targeted algorithm proposed in this paper. Our system is powered by our proposed semantic gamelog input tool that facilitates fast and accurate input of a semantic gamelog that contains basic semantic information of atomic events. When an interesting event occurs, our system performs boundary detection of these events by combining features extracted from the video with additional information from the semantic gamelog. This additional information facilitates our system to achieve accurate and very fast boundary detection of these events to support our live event alert service. Our system also implements a gamelog translation machine which translates the semantic gamelog (encoded in a game-specific code) into any natural language, provided that there is a configuration file for that language. Combining our gamelog translation machine with existing text-to-speech technology, we provide the on-the-fly language selection service. (Currently, our system supports English, Chinese, and Malay.)     

A hybrid architecture for analog video broadcast and B-ISDNservices in customer premises networks

The use of SCM (subcarrier multiplexing) transmission to deliver broadcast analog video signals within a CPN (customer premises network) as an overlay to an all-digital B-ISDN (broadband integrated services digital network) is considered. The feasibility of a proposal where the analog and digital signals are carried on different wavelengths is shown. An architecture for an optical CPN, termed H-Bus and incorporating emerging broadband SONET and ATM (asynchronous transfer mode) standards, is taken as a baseline for the delivery of switched digital, two-way voice, data, and video services. An optical overlay for the distribution of analog, broadcast video services using subcarrier multiplexing is considered. Several key alternatives associated with the delivery of broadcast video services are assessed, including signal quality, number of simultaneous channels, number of user terminals to be served, and modulation format. These issues are considered in terms of their impact on the interface with the public local exchange network and on the complexity, topology, and cost of the CPN     

Integrated alerting and system broadcast channel for a wirelessaccess system

A protocol is described which allows a wireless access system to dynamically multiplex the alerting, system information, and priority access request subchannels on its system-wide broadcast channel. These subchannels each have different requirements with respect to the message length and position within the framing structure; the described protocol meets each of their requirements. The protocol efficiently accommodates a wide range of alerting traffic levels and provides for efficient downloading of system information to subscriber units by using excess capacity when alerting traffic is low. It provides error detection capabilities above that provided by the radio channel alone and is easily extendible to accommodate other services such as paging and low bandwidth broadcast messaging. The flexibility provided by this protocol could permit a broad range of network architectures for wireless access     

A semantic framework for video genre classification and event analysis

Semantic video analysis is a key issue in digital video applications, including video retrieval, annotation, and management. Most existing work on semantic video analysis is mainly focused on event detection for specific video genres, while the genre classification is treated as another independent issue. In this paper, we present a semantic framework for weakly supervised video genre classification and event analysis jointly by using probabilistic models for MPEG video streams. Several computable semantic features that can accurately reflect the event attributes are derived. Based on an intensive analysis on the connection between video genres and the contextual relationship among events, as well as the statistical characteristics of dominant event, a hidden Markov model (HMM) and naive Bayesian classifier (NBC) based analysis algorithm is proposed for video genre classification. Another Gaussian mixture model (GMM) is built to detect the contained events using the same semantic features, whilst an event adjustment strategy is proposed according to an analysis on the GMM structure and pre-definition of video events. Subsequently, a special event is recognized based on the detected events by another HMM. The simulative experiments on video genre classification and event analysis using a large number of video data sets demonstrate the promising performance of the proposed framework for semantic video analysis.     

Low cost measurement system for broadcast power amplifiers

For the fast prototyping, production, and delivery of commercial radio frequency products/systems, accurate and reliable test systems are necessary. These systems are usually product customized and thus expensive solutions, capable of performing all necessary measurements for a specific product. The purpose of this paper is to present a flexible cost‐effective test solution, capable of realizing all necessary measurement on a high output power amplifier system greater than 500 W, and to generate essential reports. These reports allow the system operator to (i) perform an analysis and a statistical comparison among various products, assuring that the quality is the same for all products; and (ii) retain products that present a performance poorer than other similar products, without a rigorous technical analysis, thus increasing efficiency in factory assembly line. Copyright © 2013 John Wiley & Sons, Ltd.     

多波束宽带卫星广播系统的自适应功率分配

随着互联网和宽带通信需求的不断增长,未来的多波束宽带卫星系统将主要工作在Ka频段或更高频段,在这些高频段下,时变的天气和降雨是影响系统性能的主要因素。针对这一问题,提出了基于公平性指标的启发式多波束动态功率分配方法,并采用了波束用户分群方法降低算法的计算复杂度,从而能实现系统性能和复杂性之间的交换。仿真结果表明,相比于传统的静态功率分配算法,提出的算法可以在雨衰环境下服务更多的用户,实现更高的功率效率;另一方面,算法也明显提高了系统资源分配的公平性。     

Scalable architecture for word HMM-based speech recognition and VLSI implementation in complete system

This paper describes a scalable architecture for real-time speech recognizers based on word hidden Markov models (HMMs) that provide high recognition accuracy for word recognition tasks. However, the size of their recognition vocabulary is small because its extremely high computational costs cause long processing times. To achieve high-speed operations, we developed a VLSI system that has a scalable architecture. The architecture effectively uses parallel computations on the word HMM structure. It can reduce processing time and/or extend the word vocabulary. To explore the practicality of our architecture, we designed and evaluated a complete system recognizer, including speech analysis and noise robustness parts, on a 0.18-/spl mu/m CMOS standard cell library and field-programmable gate array. In the CMOS standard-cell implementation, the total processing time is 56.9 /spl mu/s/word at an operating frequency of 80 MHz in a single system. The recognizer gives a real-time response using an 800-word vocabulary.     

机载广播/电视系统试飞技术

结合某机载广播/电视系统的试飞内容,对该试飞领域进行了技术探索,本文着重介绍了测试区域选择方法、测试点布局设计以及场强辅助分析等。     

基于EasyDL平台视频事件监测系统在铁路运维中的应用

人工智能技术日益发展,为了更好地减轻铁路视频监控人员工作量,保障铁路作业人员安全,减少事故发生,文章针对铁路运营维护的5个场景,设计了一种基于EasyDL平台的视频事件监测系统。此系统基于人工智能EasyDL平台,建立未佩戴安全帽、未穿防护服、特殊区域人员徘徊等机器学习模型,利用相关模型识别铁路作业人员的一些违规行为,及时记录并给出警示。测试结果表明,该系统能够准确识别摄像头抓拍到的违规事件,有助于进一步保障铁路作业人员的安全。     

Bidirectional WDM passive optical network for simultaneous transmission of data and digital broadcast video service

We have demonstrated an easily upgradable bidirectional passive optical network for the simultaneous transmission of wavelength-division-multiplexing channels and digital broadcast video signals. The proposed network could transmit 15 2.5-Gb/s downstream channels, 15 155-Mb/s upstream channels, and one broadcast signal consisting of more than 70 digital video channels.     

Integrating the scene length characteristics of MPEG video bitstreams into a direct broadcast satellite network with return channel system

In order to optimize the network resources, we should incorporate all the available information into the network design. However, incorporating irrelevant information may increase the design complexity and/or decrease the performance of the network. In this paper, we investigate the relevance of integrating the scene length characteristics of moving pictures expert group (MPEG) coded video bitstreams into a direct broadcast satellite (DBS) network with return channel system (DVB‐RCS). Due to the complexity of the studied system, unless disputable simplifications are made, it is hard to achieve a mathematical foundation for this integration. Our analysis relies on extensive set of simulations. Firstly, we achieve the scene length distributions for MPEG bitstreams based on the proposed scene change models and their subjective observations of the actual video. We show that these models may be used to estimate the scene length of MPEG bitstreams. We then integrate this estimation into a DBS network simulator. Finally, we show that the scene length characteristics may be used to improve the DBS network performance under certain conditions. Copyright © 2004 John Wiley & Sons, Ltd.     

小型广播系统播控端单片机软件设计

为了在小型音乐广播系统中实现对10路发射信号传输频点的控制和对音乐类型数据的接收及存储．提出了一种基于ATmegal6单片机和BHl415F调频芯片的播控端软件设计方案并给出了调试仿真方法。该方案中采用ATmega16单片机从12C主设备接收音乐类型数据、频点控制数据，并且将频点控制数据处理后，转发给BHl415调频芯片，实现频点控制；将音乐类型数据存储起来，供语音录放模块控制播放顺序用。调试仿真和实际应用结果表明．本方案可正确控制调制频点，高效接收和存储音乐类型数据。