基于H.264的远距离无线视频监控系统方案设计

设计了一种基于H.264压缩标准的远距离视频监控系统,详细给出了该系统的硬件与软件设计,并针对RTP流媒体网络数据传输中的若干问题给出了相应的解决方案。实践证明,系统运行稳定可靠,设计合理。     

基于TMDXEVM6446的网络视频监控系统

网络视频监控系统是集视频编解码和流媒体传输技术为一体的综合系统,提供了实时快捷的监控服务,近年来得到越来越广泛的应用。本文详细介绍了H.264/AVC视频编码新标准在TMDXEVM6446平台上的移植和优化,并完成了基于H.264编解码的网络视频监控系统完整的设计与实现。     

架构在视频门禁系统中的应用——基于JMF的流媒体服务器

设计了一个基于JMF技术的流媒体服务器架构,并应用于视频门禁系统中。该架构在逻辑上是BS三层结构,采用组播进行数据传输。系统采用RTP/RTCP协议实现MPEG实时流媒体服务,在IP网络中运行良好。     

数字监控市场的新宠——网络视频服务器

目前，在视频图像监控领域，数字化、网络化、智能化已成为一种发展趋势．数字视频图像监控系统也逐步进入大规模商业应用阶段；和传统的第一代模拟视频监控系统相比．数字视频图像监控系统至今已经历了两个发展阶段：20世纪90年代末期．利用计称为第二代准数字化本地视频监控系统．典型的产品就是数字硬盘录像机（DVR）：21世纪初期．以网络为依托．以数字视频处理技术为核心，综合利用光电传感器、数字化图像处理、嵌八式计算机系统、数据传输网络、自动控制和人工智能等技术的一种新型数字监控系统横空出世，它不仅具有第一代本地数字监控系统所具有的计算机快速处理能力、数字信息抗干扰能力、便于快速查询记录、视频图像清晰及单机显示多路图像等优点，而且依托网络．真正发挥了宽带网络的优势。     

3G无线流媒体技术在水利监控的应用

随着3G网络的商用,流媒体技术也拓展到无线领域,可适用于监控等多种业务。介绍了流媒体的概念,分析了流媒体编解码和嵌入式视频Web服务器技术,重点就3G流媒体在水利监控中的应用和水利3G监控系统的组成进行阐述和说明。将3G流媒体应用于水利监控,可节省人力和监视设备,推进水利视频监控系统向智能化的综合管理系统发展。     

基于S3C2440嵌入式平台的USB摄像头视频监控

针对传统视频监控系统造价昂贵,安装不便的缺点,提出了一种基于嵌入式的远程视频实时监控系统设计方案。系统以S3C2440为硬件平台、开源的Linux为软件平台,采用通用的USB摄像头,通过内核提供的Video4Linux接口对视频信息进行采集处理,由符合TCP网络传输的mjpg-streamer流媒体服务将视频传送到网络。实验结果表明,经过采集处理后的视频效果和实时性都达到了监控的要求。     

3G网络的移动视频监控系统

移动流媒体应用是基于3G独特高数据带宽的业务应用,是3G业务网络中最具市场潜力的增值业务类型。为了进一步推广移动流媒体技术的应用,该文将3G移动网络和固网视频监控结合起来,实现两者优势互补,提出了一种基于3G网络的移动视频监控系统模型,此模型能够弥补传统移动网络和固网的不足对移动视频监控系统的设计具有一定的指导意义。     

网络数字视频监控系统

本文较全面地探讨：数字网络视频临近系统的应用范围：系统组成与视频数据传输协议，网络数字视频监控系统的应用例，还介绍了无线网络数字视频监控系统。     

基于实时流媒体服务的多源应用层组播系统

针对矿区网络大容量视频信号传输,通过在现有网路中部署流媒体服务节点,构建基于实时流媒体服务的多源应用层组播系统,并提出一种基于度和延时约束的路由算法,进行组播树节点的管理和优化。该系统实现简单、路由健壮性高,与传统C/S模式视频监控系统相比,在同等网络状况和运行环境下,传输视频流的网络丢包率降低50%以上。     

基于嵌入式Web远程视频监控系统的设计与实现

介绍一种基于嵌入式Linux和ARM微处理器的视频监控系统。该系统通过USB摄像头采集视频数据．经MPEG-4对视频流媒体进行压缩编码,采用端对端的实时传输协议／实时传输控制协议（RTP／RTCP）实现视频数据的网络传输,采用CGI技术、AJAX技术、B／S模式浏览及动态IP绑定。整个系统建立在嵌入式的构架上,能独立完成实时视频的采集、处理及传输．可应用于家居安防、网络视频、远程监控等领域。     

混合结构视频网格的构造与性能分析

针对可扩展视频网格结构中,由于加盟服务器数量不足所引起的区域服务器负载波动随在线用户数量变化过大的问题,引入P2P技术构造混合结构的视频网格,实现普通客户端之间视频流数据的直接传输。论述了P2P点播组的构成,资源的管理和调度算法,异常情况的处理过程。实验表明,混合结构的视频网格具有较好的性能,能够降低区域服务器负载的波动范围。     

Optimal Coding of Multilayer and Multiversion Video Streams

Traditional video servers partially cope with heterogeneous client populations by maintaining a few versions of the same stream with different bit rates. More recent video servers leverage multilayer scalable coding techniques to customize the quality for individual clients. In both cases, heuristic, error-prone, techniques are currently used by administrators to determine either the rate of each stream version, or the granularity and rate of each layer in a multilayer scalable stream. In this paper, we propose an algorithm to determine the optimal rate and encoding granularity of each layer in a scalable video stream that maximizes a system-defined utility function for a given client distribution. The proposed algorithm can be used to compute the optimal rates of multiversion streams as well. Our algorithm is general in the sense that it can employ arbitrary utility functions for clients. We implement our algorithm and verify its optimality, and we show how various structuring of scalable video streams affect the client utilities. To demonstrate the generality of our algorithm, we consider three utility functions in our experiments. These utility functions model various aspects of streaming systems, including the effective rate received by clients, the mismatch between client bandwidth and received stream rate, and the client-perceived quality in terms of PSNR. We compare our algorithm against a heuristic algorithm that has been used before in the literature, and we show that our algorithm outperforms it in all cases.     

影响多媒体服务器性能的关键因素研究

在构建大规模视频服务系统时 ,基于层次型多服务器群的体系结构在吞吐率、可扩展性、经济性等方面都有其突出的优势 ,尤其适合于在因特网上的应用 .但是 ,要充分发挥和提高视频服务系统的性能 ,还要针对一些主要的瓶颈(如服务器磁盘 I/ O带宽与网络带宽 ) ,解决好一系列的问题 .本文分析了影响多媒体视频服务器性能的一些主要因素 ,如视频服务器的体系结构、服务器与客户端之间的数据传送方式、媒体数据在视频服务器存储子系统中的分布与放置方式、对磁盘访问请求的调度、单服务器中的缓存及多服务器间协同缓存的管理、接入控制策略、流调度策略等 ,这些因素对视频服务器的性能与吞吐率有着极大的影响 .本文还介绍了一些适用于大规模视频服务系统的性能优化技术 ,如广播、批处理等流调度策略 .在构建视频服务器系统时 ,只有综合考虑这些因素 ,才能真正提高服务器乃至整个视频服务系统的吞吐率 ,并较好地满足客户的 Qo S要求     

SSMU流媒体服务器性能测评系统的设计与实现

流媒体服务器性能的关键指标是流输出能力和所能支持的并发请求数量。本文提出一种名为SSMU的流媒体服务器测评系统,并且分析了流媒体服务器的性能测评指标。该系统只需要一台或几台客户机就能实现流媒体服务器的性能测评。     

On network CoProcessors for scalable, predictable media services

This paper presents the embedded realization and experimental evaluation of a media stream scheduler on network interface (NI) CoProcessor boards. When using media frames as scheduling units, the scheduler is able to operate in real-time on streams traversing the CoProcessor, resulting in its ability to stream video to remote clients at real-time rates. This paper presents a detailed evaluation of the effects of placing application or kernel-level functionality, like packet scheduling on NIs, rather than the host machines to which they are attached. The main benefits of such placement are: 1) that traffic is eliminated from the host bus and memory subsystem, thereby allowing increased host CPU utilization for other tasks, and 2) that NI-based scheduling is immune to host-CPU loading, unlike host-based media schedulers that are easily affected even by transient load conditions. An outcome of this work is a proposed cluster architecture for building scalable media servers by distributing schedulers and media stream producers across the multiple NIs used by a single server and by clustering a number of such servers using commodity network hardware and software.     

Loopback: exploiting collaborative caches for large-scale streaming

In this paper, we propose a Loopback approach in a two-level streaming architecture to exploit collaborative client/proxy buffers for improving the quality and efficiency of large-scale streaming applications. At the upper level we use a content delivery network (CDN) to deliver video from a central server to proxy servers. At the lower level a proxy server delivers video with the help of collaborative client caches. In particular, a proxy server and its clients in a local domain cache different portions of a video and form delivery loops. In each loop, a single video stream originates at the proxy, passes through a number of clients, and finally is passed back to the proxy. As a result, with limited bandwidth and storage space contributed by collaborative clients, we are able to significantly reduce the required network bandwidth, I/O bandwidth, and cache space of a proxy. Furthermore, we develop a local repair scheme to address the client failure issue for enhancing service quality and eliminating most required repairing load at the central server. For popular videos, our local repair scheme is able to handle most of single-client failures without service disruption and retransmissions from the central server. Our analysis and simulations have shown the effectiveness of the proposed scheme.     

一种基于QoS的MPEG-4视频泵实现方法

基于QoS的MPEG-4视频泵技术是具有QoS功能的MPEG-4视频服务器设计中的核心技术之一。在MPEG-4标准框架下,利用多框架多级别的视频编码方案,对MPEG-4视频泵进行了扩充设计,可在64bps～2Mbps的带宽范围内,为基于RTP/RTCP传输机制的视频服务提供服务质量保证。基于QoS的MPEG-4视频泵在视频服务器中的应用,为实时、可变码率的流媒体服务提供可行的解决方案。     

Super-Streaming: A New Object Delivery Paradigm for Continuous Media Servers

A number of studies have focused on the design of continuous media, CM, (e.g., video and audio) servers to support the real-time delivery of CM objects. These systems have been deployed in local environments such as hotels, hospitals and cruise ships to support media-on-demand applications. They typically stream CM objects to the clients with the objective of minimizing the buffer space required at the client site. This objective can now be relaxed due to the availability of inexpensive storage devices at the client side. Therefore, we propose a Super-streaming paradigm that can utilize the client side resources in order to improve the utilization of the CM server. To support super-streaming, we propose a technique to enable the CM servers to deliver CM objects at a rate higher than their display bandwidth requirement. We also propose alternative admission control policies to downgrade super-streams in favor of regular streams when the resources are scarce. We demonstrate the superiority of our paradigm over streaming with both analytical and simulation models.Moreover, new distributed applications such as distant-learning, digital libraries, and home entertainment require the delivery of CM objects to geographically disbursed clients. For quality purposes, recently many studies proposed dedicated distributed architectures to support these types of applications. We extend our super-streaming paradigm to be applicable in such distributed architectures. We propose a sophisticated resource management policy to support super-streaming in the presence of multiple servers, network links and clients. Due to the complexity involved in modeling these architectures, we only evaluate the performance of super-streaming by a simulation study.     

SMTVS:一种基于H.264的手机电视系统

手机电视系统必须能够适应网络和客户端的异构性、无线信道的多变性等特点.提出一种手机电视系统SMTVS,流媒体服务器在不同码率的H.264视频流之间进行切换以适应网络状况的变化;代理服务器之间构成一个内容分送网络,视频数据通过应用层组播的方式传输到各个代理服务器,降低了服务器的负载,提高了网络资源利用率;代理服务器接收到视频数据之后,针对无线链路的状况对数据进行处理后再发送到客户端,以适应最终用户的不同需求;客户端根据网络状况来动态调整播放速率,避免显示缓冲区下溢和上溢.通过流媒体服务器、代理服务器以及客户端的协作,实现了视频数据在无线信道上的自适应传输.     

基于视频内容的多媒体网络接纳控制

提出一种新的基于视频内容的多媒体网络服务接纳控制方法。根据MPEGVBR视频图像的内容复杂度,利用人眼对视频内容的惰性,对不同视频流在固定窗口下赋予不同的丢帧优先级。在网络负载加重时,在客户可容忍的QoS范围内,通过适当丢弃B帧,不但增加了多媒体网络的并发客户数,而且也提高了网络资源的利用率。