基于Web服务技术的分布式电视节目制作环境研究
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摘要
随着信息技术的发展，传统的基于录像机的线性编辑手段正在被非线性编辑所替代，电视台正在进入一个数字化、网络化的时代。目前国内很多电视台都建立了非线性编辑网络系统，从而提高了节目制作效率，降低了节目制作成本。但这些网络系统大多基于C/S两层体系结构，从而导致了许多问题。其中最突出的就是很难与电视台内的其它应用系统进行集成，这就造成了各个系统间无法相互访问和协同工作，在电视台内形成了一个个的信息孤岛，给工作带来了极大的不便，严重阻碍了电视台节目制、播、存网络一体化的进程。
Web服务(Web Services)是近年来刚刚出现的一种分布式计算技术，它将紧密耦合的n层计算技术与松散耦合的Web概念相结合，允许客户端通过标准网络传输协议HTTP调用远程的Web服务，调用请求和返回结果都用XML进行编码，从而实现了平台无关性。Web服务平台无关和松散耦合的特点使得基于Web服务技术的系统之间能够方便地进行集成和互操作。正因为如此，Web服务技术成为建立分布式电视节目制作环境理想的技术手段。
本文首先对电视节目制作系统的工作原理和技术现状进行了阐述，并指出了存在的问题及其原因，然后在对Web服务技术的最新学术和应用成果进行了详细研究的基础上，建立了基于Web服务的分布式电视节目制作环境，有效地解决了不同系统之间的集成问题。论文不仅给出了基于Web服务的分布式电视节目制作环境的工作原理和软件体系结构，而且给出了在．NET环境下建立和调用Web服务的具体方法和运行结果。论文最后对系统的特点和性能进行了讨论。
当然，建立基于Web服务技术的分布式电视节目制作环境所涉及技术问题比论文中研究的内容要复杂很多，例如复杂业务逻辑的抽取、遗产系统的处理、视音频素材的交换格式、Web服务的安全等，都有待于进一步的研究和实践。
With the development of IT technology, traditional linear television production method is replaced by nonlinear method. TV station is coming into a digitalizing and networking era. Now, many television production nonlinear edit networks have been established in China, and they play an important role in raising efficiency and reducing costs. However, because most of them use CIS software architecture, there are many problems such as difficult to integrate with other systems. Thus many isolated networks are formed in TV station, and this brings much inconvenience.
Web Services is a new distributed computing technology, it combines the tight -coupling N-tier computing technology and the concept of loose-coupling Web together, thus allows the clients access the distant Web Services via standard network transfer protocol (HTTP). The messages of request and response are all encoded in XML format. All this makes Web Services platform-independent. The loose-coupling and platform-independent features of Web Services make it easy to integrate and inter-operate with other system. Hence, Web Services becomes the ideal technology to set up a distributed television production system.
At the beginning of the paper, the principle and status quo of television nonlinear-edit network are expounded, and the problems are also pointed out. With the studies of the latest technologies and application fruits of Web Services, a distributed television production environment -based on Web Services is established. The paper not only proposes the principle and software architecture of the system, but also shows how to create and invoke Web Services. At the end of the paper, the performance of the system is discussed.
Of course, establishing a Web Services based distributed television production environment must be much more complex than the paper described. There are still many difficulties, such as how to acquire the complex business logic, how to deal with the legacy system, what format to use for the multimedia material exchange, how about the safety of Web services, etc. All these need further study.
Web服务(Web Services)是近年来刚刚出现的一种分布式计算技术，它将紧密耦合的n层计算技术与松散耦合的Web概念相结合，允许客户端通过标准网络传输协议HTTP调用远程的Web服务，调用请求和返回结果都用XML进行编码，从而实现了平台无关性。Web服务平台无关和松散耦合的特点使得基于Web服务技术的系统之间能够方便地进行集成和互操作。正因为如此，Web服务技术成为建立分布式电视节目制作环境理想的技术手段。
本文首先对电视节目制作系统的工作原理和技术现状进行了阐述，并指出了存在的问题及其原因，然后在对Web服务技术的最新学术和应用成果进行了详细研究的基础上，建立了基于Web服务的分布式电视节目制作环境，有效地解决了不同系统之间的集成问题。论文不仅给出了基于Web服务的分布式电视节目制作环境的工作原理和软件体系结构，而且给出了在．NET环境下建立和调用Web服务的具体方法和运行结果。论文最后对系统的特点和性能进行了讨论。
当然，建立基于Web服务技术的分布式电视节目制作环境所涉及技术问题比论文中研究的内容要复杂很多，例如复杂业务逻辑的抽取、遗产系统的处理、视音频素材的交换格式、Web服务的安全等，都有待于进一步的研究和实践。
With the development of IT technology, traditional linear television production method is replaced by nonlinear method. TV station is coming into a digitalizing and networking era. Now, many television production nonlinear edit networks have been established in China, and they play an important role in raising efficiency and reducing costs. However, because most of them use CIS software architecture, there are many problems such as difficult to integrate with other systems. Thus many isolated networks are formed in TV station, and this brings much inconvenience.
Web Services is a new distributed computing technology, it combines the tight -coupling N-tier computing technology and the concept of loose-coupling Web together, thus allows the clients access the distant Web Services via standard network transfer protocol (HTTP). The messages of request and response are all encoded in XML format. All this makes Web Services platform-independent. The loose-coupling and platform-independent features of Web Services make it easy to integrate and inter-operate with other system. Hence, Web Services becomes the ideal technology to set up a distributed television production system.
At the beginning of the paper, the principle and status quo of television nonlinear-edit network are expounded, and the problems are also pointed out. With the studies of the latest technologies and application fruits of Web Services, a distributed television production environment -based on Web Services is established. The paper not only proposes the principle and software architecture of the system, but also shows how to create and invoke Web Services. At the end of the paper, the performance of the system is discussed.
Of course, establishing a Web Services based distributed television production environment must be much more complex than the paper described. There are still many difficulties, such as how to acquire the complex business logic, how to deal with the legacy system, what format to use for the multimedia material exchange, how about the safety of Web services, etc. All these need further study.
引文
[1] 闵瑞麟，电视台数字网络化的思路，北京国际电视技术研讨会文集，2000
[2] Lalit Kumar Jain, A Distributed、Component-based Solution for Scientific Information Management, http://cs. oregonstate. edu/research/thesis.html
[3] 王辅东，魏峻，面向Web服务的工作流建模语言比较，计算机应用，2002(11)
[4] 朱三元，钱乐秋，宿为民，软件软件工程技术概论，北京：科学出版社，2002
[5] Xia Cai, Michael R. Ly, Component-Based Software Engineering:Technologies, Development Frameworks, and Quality Assurance Schemes. 2000 IEEE
[6] 徐锋，防洪调度系统软件构件技术研究与实现，河海大学硕士学位论文，2000
[7] 潘爱民，COM原理与应用，北京：清华大学出版社，1999
[8] 黄贤英，在J2EE平台上使用EJB开发企业应用，计算机应用研究，2001(12)
[9] Sun Microsystems Inc, Enterprise Javabeans Specification Version 2.0
[10] Magnus Larsson, Applying Configuration Management Techniques to Component-Based Systems, http://www. idt. mdh. se/~mlo/Research/lic_thesis_final. pdf
[11] 何宗就，中央电视台技术现状与发展思路，北京国际电视技术研讨会文集，2000
[12] 徐晓展，徐品，基于数字视频网络的节目信息管理技术，中国传媒科技，2001(5)
[13] 王良金，吴仁炳，丁久量，视频网络技术，广播与电视技术，2003(1)
[14] W3C, Web Services Architecture, http://www. w3. org/TR/2002/WD-ws-arch-20021114
[15] Visual Studio 实现可编程的 Web, http://www. microsoft. com/china/msdn/vstudio/ technical/articles/webservices. asp
[16] Sue Hildreth,Web Services: The Next Generation of Distributed Computing, http://www. flashline. com/Content/ebizq/webservicesl. jsp?sid=1043201740468-3657599381-53
[17] Web 服务-Web 的下一次革命，http://www-900. ibm. com/developerWorks/cn/education/ webservices/wsbasics/tutorial/index. shtml
[18] 蒋雄伟，马范援，中间件与分布式计算，计算机应用，2002(4)
[19] W3C, Web Services Architecture, http://www. w3. org/TR/2002/WD-ws-arch-20021114/
[20] Kent Tegels, Tony Baer, .NET Framework编程思想，北京：清华大学出版社，2002
[21] Elliotte Rusty Harold, XML实用大全，北京：中国水利水电出版社，2000
[22] W3C, Extensible Markup Language (XML) 1.0, http://www. w3. org/TR/REC-xml
[23] W3C, SOAP Version 1.2, http://www. w3. org/TR/2002/CR-soap12-part1-20021219/
[24] 吕曦，王化文，Web Service的架构与协议，计算机应用，2002(12)
[25] W3C, Web Services Description Language (WSDL), http://www. w3. org/TR/2003/ WD-wsdl12-20030303
[26] Robert Tabor,.NET XML Web服务，北京：机械工业出版社，2002
[27] 顾建国，朱光荣，非线性编辑网络的设计原则，现代电视技术，2002(7)
[28] 杜百川，数字电视，北京：中国电视学会广播电视技术分会，1998
[29] Avid Demonstrates Integrated Solutions that "Make,Manage and Move Media" at NAB 2001,http://www.avid.com
[30] P.J.Brightwell,P.N.Tudor.A Distributed Programming Environment Using IT-based Technology, SMPTE Journal,2001(11)
[31] 赵季伟，有感法国嘎纳电视台的技术体系，现代电视技术，2003(2)
[32] 雷骏雄，宁汝新，张旭，基于XML的PDM系统体系结构与实现，计算机应用，2003(1)
[33] Graham Glass,The Web services (r)evolution,http://www-106.ibm.com/developerworks/ webservices/library/ws-peer3/
[34] 颜军，曹嵩，钱钟，徐家恺，一种四层结构的Internet应用，计算机工程，2003(3)
[35] Richard Anderson,ASP.NET 1.0高级编程，北京：清华大学出版社，2002
[36] Evangelos Petroutsos,Visual Basic. NET从入门到精通，北京：电子工业出版社，2002(7)
[37] Fred Barwell,Richard Blair,VB.NET高级编程，北京：清华大学出版社，2002
[38] Mridula Parihar,ASP.NET Bible，Hungry Minds，2002
[2] Lalit Kumar Jain, A Distributed、Component-based Solution for Scientific Information Management, http://cs. oregonstate. edu/research/thesis.html
[3] 王辅东，魏峻，面向Web服务的工作流建模语言比较，计算机应用，2002(11)
[4] 朱三元，钱乐秋，宿为民，软件软件工程技术概论，北京：科学出版社，2002
[5] Xia Cai, Michael R. Ly, Component-Based Software Engineering:Technologies, Development Frameworks, and Quality Assurance Schemes. 2000 IEEE
[6] 徐锋，防洪调度系统软件构件技术研究与实现，河海大学硕士学位论文，2000
[7] 潘爱民，COM原理与应用，北京：清华大学出版社，1999
[8] 黄贤英，在J2EE平台上使用EJB开发企业应用，计算机应用研究，2001(12)
[9] Sun Microsystems Inc, Enterprise Javabeans Specification Version 2.0
[10] Magnus Larsson, Applying Configuration Management Techniques to Component-Based Systems, http://www. idt. mdh. se/~mlo/Research/lic_thesis_final. pdf
[11] 何宗就，中央电视台技术现状与发展思路，北京国际电视技术研讨会文集，2000
[12] 徐晓展，徐品，基于数字视频网络的节目信息管理技术，中国传媒科技，2001(5)
[13] 王良金，吴仁炳，丁久量，视频网络技术，广播与电视技术，2003(1)
[14] W3C, Web Services Architecture, http://www. w3. org/TR/2002/WD-ws-arch-20021114
[15] Visual Studio 实现可编程的 Web, http://www. microsoft. com/china/msdn/vstudio/ technical/articles/webservices. asp
[16] Sue Hildreth,Web Services: The Next Generation of Distributed Computing, http://www. flashline. com/Content/ebizq/webservicesl. jsp?sid=1043201740468-3657599381-53
[17] Web 服务-Web 的下一次革命，http://www-900. ibm. com/developerWorks/cn/education/ webservices/wsbasics/tutorial/index. shtml
[18] 蒋雄伟，马范援，中间件与分布式计算，计算机应用，2002(4)
[19] W3C, Web Services Architecture, http://www. w3. org/TR/2002/WD-ws-arch-20021114/
[20] Kent Tegels, Tony Baer, .NET Framework编程思想，北京：清华大学出版社，2002
[21] Elliotte Rusty Harold, XML实用大全，北京：中国水利水电出版社，2000
[22] W3C, Extensible Markup Language (XML) 1.0, http://www. w3. org/TR/REC-xml
[23] W3C, SOAP Version 1.2, http://www. w3. org/TR/2002/CR-soap12-part1-20021219/
[24] 吕曦，王化文，Web Service的架构与协议，计算机应用，2002(12)
[25] W3C, Web Services Description Language (WSDL), http://www. w3. org/TR/2003/ WD-wsdl12-20030303
[26] Robert Tabor,.NET XML Web服务，北京：机械工业出版社，2002
[27] 顾建国，朱光荣，非线性编辑网络的设计原则，现代电视技术，2002(7)
[28] 杜百川，数字电视，北京：中国电视学会广播电视技术分会，1998
[29] Avid Demonstrates Integrated Solutions that "Make,Manage and Move Media" at NAB 2001,http://www.avid.com
[30] P.J.Brightwell,P.N.Tudor.A Distributed Programming Environment Using IT-based Technology, SMPTE Journal,2001(11)
[31] 赵季伟，有感法国嘎纳电视台的技术体系，现代电视技术，2003(2)
[32] 雷骏雄，宁汝新，张旭，基于XML的PDM系统体系结构与实现，计算机应用，2003(1)
[33] Graham Glass,The Web services (r)evolution,http://www-106.ibm.com/developerworks/ webservices/library/ws-peer3/
[34] 颜军，曹嵩，钱钟，徐家恺，一种四层结构的Internet应用，计算机工程，2003(3)
[35] Richard Anderson,ASP.NET 1.0高级编程，北京：清华大学出版社，2002
[36] Evangelos Petroutsos,Visual Basic. NET从入门到精通，北京：电子工业出版社，2002(7)
[37] Fred Barwell,Richard Blair,VB.NET高级编程，北京：清华大学出版社，2002
[38] Mridula Parihar,ASP.NET Bible，Hungry Minds，2002