A Video Server cost/performance Estimator tool

The Video Server Estimator (VSE) is an analytical tool which allows a user to perform a cost/performance analysis of video servers with hierarchical storage. The underlying model comprises multiple systems, main memory, expanded storage, disks and a tape library. The main objective of the tool is to optimally allocate the video files to different storage media based on the system parameters and the video file request probability distribution. The cost and the size of the video server that can accommodate a customer profile are determined. Furthermore, the impact of design parameters on the cost and performance are examined through a parametric analysis.     

Design and Implementation of the Stony Brook Video Server

The system architecture of the Stony Brook Video Server (SBVS), which guarantees end-to-end real-time video playback in a client-server setting, is presented. SBVS employs a real-time network access protocol, RETHER, to use existing Ethernet hardware as the underlying communications media. The video server tightly integrates the bandwidth guarantee mechanisms for network transport and disk I/O. SBVS's stream-by-stream disk scheduling scheme optimizes the effective disk bandwidth without incurring significant scheduling overhead. To demonstrate the feasibility of the proposed architecture, we have implemented a prototype called SBVS-1, which can support five concurrent MPEG-1 video streams on an Intel 486DX2/EISA PC. To our knowledge, this system is the first video server that provides an end-to-end performance guarantee from the server's disks to the each user's display over standard Ethernet. This paper describes the implementation details of integrating network and I/O bandwidth guarantee mechanisms, and the performance measurements that drive and/or validate our design decisions. © 1997 by John Wiley & Sons, Ltd.     

视频存储技术发展综述

网络技术的不断发展,远程视频的应用研究成为计算机领域的一个研究热点,而视频存储技术的研究是这一领域内研究最早、发展较为成熟的一部分。文章主要综述和比较了20世纪90年代中期以来视频存储方面的关键技术,并对这些技术的优缺点及使用的局限性给出了评说。     

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.     

电信级视频点播系统的设计与实现

视频点播服务是一种新的信息服务。作为信息服务运营商,电信需要构建电信级的视频点播系统以便有效提供电信级视频点播服务。针对电信级视频点播服务的设计需求,本文提出了一个电信级视频点播层次型分布式系统架构,并在该架构下,整合视频服务子系统、容错子系统、节目管理子系统、节目分发子系统、节目采编子系统、用户认证计费系统和网管子系统等七大功能系统,完整地实现了一个电信级视频点播系统,最终实现了城域范围内的视频点播服务。     

面向海量高清视频数据的高性能分布式存储系统

通过对视频监控数据的特点和传统存储方案进行分析,提出一种高性能分布式存储系统解决方案.不同于传统的基于文件存储的方式,设计了一种逻辑卷结构,将非结构化的视频流数据以此结构进行组织并直接写入RAW磁盘设备,解决了传统存储方案中随机磁盘读写和磁盘碎片导致存储性能下降的问题.该方案将元数据组织为两级索引结构,分别由状态管理器和存储服务器管理,极大地减少了状态管理器需要管理元数据的数量,消除了性能瓶颈,并提供精确到秒级的检索精度.此外,该方案灵活的存储服务器分组策略和组内互备关系使得存储系统具备容错能力和线性扩展能力.系统测试结果表明,该方案在成本低廉的PC服务器上实现了单台服务器能同时记录400路1080P视频流,写入速度是本地文件系统的2.5倍.     

监控视频云存储系统

非结构化数据呈爆炸态势增长, 传统存储技术在吞吐能力可扩展性及易管理性等方面急需改进, 通过分析安保视频数据存储的问题, 设计一种云计算架构下的安保视频监控存储系统, 基于框架技术搭建了对等架构的云计算环境, 并对其中的云存储策略进行了设计和建模. 实现在廉价不可信节点上存储海量私有化只读视频数据, 并提供高效可靠地访问. 仿真结果显示, 系统的存储性能可靠度高且易于扩展, 可提供效能较高的视频云存储服务.     

嵌入式数字视频监控系统的数据存储策略

在基于vxWorks的嵌入式数字视频监控系统中实现了先进的存储策略,克服了dosFs文件系统自身的缺陷与不足,满足了实际应用的要求。     

Selection and dissemination of digital video via the Virtual Video Browser

In this paper we describe the Virtual Video Browser (VVB) software application designed to allow the interactive browsing and content-based query of a video database and to facilitate the subsequent playout of selected titles. The VVB is a manifestation of our mechanisms for the location, identification, and delivery of digital audio and video in a distributed system which can be extended to several application domains including multimedia-based home entertainment, catalog shopping, and distance learning.The VVB employs a two phase retrieval process to serve its users. In the query phase, user queries are sent to a metadata server for processing. In the subsequent playout phase, a connection is established between the client workstation and a video server for the delivery of video data. The VVB incorporates a simple query interface that lets users specify their preferences to the system and retrieve the appropriate video. The application is designed to work in a distributed environment where video sequences are stored in different databases interconnected via a network. It has been shown to be a viable target application useful for investigating research problems related to building interactive multimedia systems.Portions of this work were presented at the Intl. Workshop on Services in Distributed and Networked Environments (SDNE), Prague, Czech Republic, June 1994, and at the 1st ACM Intl. Conf. on Multimedia, Anaheim CA, August 1993.     

公共卫生数据中心存储系统设计思路与实践探讨

数据中心越来越依靠存储系统来实现核心业务数据存放、关键数据保护、高效备份和归档,以及搭建容灾系统提供业务连续性保障。充分利用先进的技术理念,将有助于建立与公共卫生业务系统相适应的存储系统,以解决当前业务系统快速增长、种类繁多、存储孤岛以及业务连续性等所带来的问题。文章以中国疾控中心为例,对业务系统所需存储资源进行梳理,阐述了基于SAN的存储整合体系、虚拟化存储体系、容灾备份系统以及云存储平台等解决方案,通过这些具体的实践探讨,期望为公共卫生行业的数据中心存储系统规划建设提供一些有益的借鉴和参考。     

Efficient Algorithms for Slot-Scheduling and Cycle-Scheduling of Video Streams on Clustered Video Servers

The granularity of scheduling video streams can be categorized as cycle-scheduling and slot-scheduling where a time cycle is further divided into time slots. To avoid resource conflict and thereby increase throughput of clustered video servers, slot-scheduling using conflict-free scheduling and especially cycle-scheduling using full-duplex scheduling and ordered scheduling are presented in the paper. Also, the analysis of the pros and cons of applying slot-scheduling and cycle-scheduling on clustered video servers are discussed.     

一种PC式数字录像机软件系统的设计与实现

介绍了一种PC(个人计算机)式数字录像机软件系统的设计与实现,给出了该软件系统的组成框架,对系统主要功能的设计与实现进行了简介,包括图像预览、录像与回放、移动侦测与遮挡、电子地图等。文章给出了系统设计中的多厂家设备支持、系统性能优化两个关键问题的设计与实现。该PC式数字录像机软件系统界面友好、功能完善、运行稳定,用户易于掌握使用,同时具有良好的可扩展性,在实际使用中效果良好。     

基于深度学习的新型视频分析系统综述

摄像设备在生活中的普及,使得视频数据快速增长,这些数据中蕴含丰富的信息.早期,研究人员基于传统的计算机视觉技术开发视频分析系统,用于提取并分析视频数据.近年来,深度学习技术在人脸识别等领域取得了突破性进展,基于深度学习的新型视频分析系统不断涌现.从应用、技术、系统等角度,综述了新型视频分析系统的研究进展.首先,回顾了视频分析系统的发展历史,指出了新型视频分析系统与传统视频分析系统的区别;其次,分析了新型视频分析系统在计算和存储两方面所面临的挑战,从视频数据的组织分布和视频分析的应用需求两方面探讨了新型视频分析系统的影响因素;再次,将新型视频分析系统划分为针对计算优化的系统和针对存储优化的系统两大类,选取其中典型的代表并介绍其核心设计理念;最后,从多个维度对比和分析了新型视频分析系统,指出了这些系统当前存在的问题,并据此展望了新型视频分析系统未来的研究和发展方向.     

数字视频监控系统的设计与实现

本文首先对数字视频监控系统进行了介绍,然后从系统的硬件和软件实现两个方面对数字视频监控系统进行系统设计,给出了相应的总体框架设计方案和视频网络传输模型。     

Design of Scalable Continuous Media Servers

Multimedia applications place high demands for quality-of-service (QoS), performance, and reliability on systems. These stringent requirements make design of cost-effective and scalable systems difficult. Therefore efficient adaptive and dynamic resource management techniques in conjunction with data placement techniques can be of great help in improving performance, scalability, and reliability of such systems. This is the focus of our paper.     

纠删码存储系统数据更新方法研究综述

在分布式存储系统中,节点故障已成为一种常态,为了保证数据的高可用性,系统通常采用数据冗余的方式.目前主要有2种冗余机制：一种是多副本,另一种是纠删码.伴随着数据量的与日俱增,多副本机制带来的效益越来越低,人们逐渐将目光转向存储效率更高的纠删码.但是纠删码本身的复杂规则导致使用纠删码的分布式存储系统的读、写、更新操作的开销相比于多副本较大.所以纠删码通常被用于冷数据或者温数据的存储,热数据这种需要频繁访问更新的场景仍然用多副本机制存储.专注于纠删码存储系统内的数据更新,从硬盘I/O、网络传输、系统优化3方面综述了目前纠删码更新相关的优化工作,对目前具有代表性的编码方案的更新性能做了对比分析,最后展望了未来研究趋势.通过分析发现目前的纠删码更新方案仍然无法获得和多副本相近的更新性能.如何在纠删码更新规则和系统架构角度优化纠删码存储系统,使其能够替换掉热数据场景下的多副本机制,降低热数据存储开销仍是未来值得深入研究的问题.     

一个数字视频监控系统的设计与实现

本文以中山移动营业厅视频监控服务为应用背景,通过对数字视频监控中的数字视频压缩、网络传输等相关技术进行分析研究,设计实现了一个集成式、多功能、综合性的数字视频监控系统。测试结果和实际应用表明,系统运行稳定可靠。     

命名数据网络中的视频传输研究综述

互联网目前已经发展为一个由实时视频和视频点播等内容分发服务主导的网络传统IP网络对于视频分发类任务的支持存在组播的部署复杂且开销大,不能有效利用多路径获取内容、对移动性的支持差和难以同时满足可靠性以及低延时需求等问题命名数据网络(named data networking,NDN)作为新型的下一代互联网体系结构,支持网...     

纠删码存储下的离线批处理作业性能优化

随着互联网数据的爆发式增长,越来越多的分布式存储系统开始引入纠删码存储机制,以在提供数据可靠性的同时降低存储开销。但纠删码机制的引入改变了数据放置模式,从而影响分布式系统上层业务的数据访问和运行效率。在异构Hadoop集群环境中,一类典型的离线批处理作业——MapReduce应用在条带式纠删码存储模式下需要从多个节点访问数据,该“一对多”的数据访问模式由于节点性能差异造成应用执行效率下降。对此,该文提出了一种基于异构环境的数据放置和任务分配策略。通过对异构集群中各节点的硬件参数和历史负载进行分析,将同一纠删码条带的数据块尽可能分布在性能相近的节点上;在系统进行任务分配时,针对各节点当前负载和运算能力确定节点的任务并发度,以平衡各节点计算资源的占用情况,从而避免因数据访问或计算过程中的资源竞争产生极端缓慢任务以致降低整个MapReduce应用的运行效率。实验结果表明,相比当前Hadoop默认的随机数据放置和任务分配策略,该文提出的异构感知数据放置策略和动态任务分配策略能够在不同类型的MapReduce应用中有效削弱任务的长尾效应,使得作业整体运行时间节约10.5%～42%,验证了该方案的...     

基于计算机与DSP的智能视频系统的分析与研究

近几年来随着计算机性能和DSP芯片性能的不断提高,出现了智能视频这一新兴技术,其应用极大地扩展了人们对于现场情况的控制力,并且使视频监控更加准确及时,已成为未来视频发展的新方向。基于计算机视觉技术和DSP技术的发展,提出两种分别基于计算机与DSP的智能视频系统实现方案,同时对各自的软件实现方面做了较为详尽的介绍。在基于计算机的系统中由于采用了OpenCV视觉库使视频开发更加迅：DSP方面采用的是TI公司刚刚推出的TMS320DM6446,其独特的设计使得图像处理更加迅速,充分满足现场实时性需求。