关于数字视音频播出与控制的一些关键技术的研究

【作者】 杨俊；

【导师】 蔡宣平；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2002， 硕士

【摘要】 传统的电视节目播控技术，以磁带录像机为核心，因此又被称为磁带播出方式。随着数字信息技术的不断发展，电视广播开始步入数字时代。目前，基于硬盘服务器的全数字电视播控系统已成为广电行业研究与应用的热点，该类系统涵盖了诸多核心与关键技术，它们都是极具理论意义和实用价值的研究课题。本课题对基于硬盘的数字音视频播控技术的研究正是在此背景下开展，目前该技术已得到国内外相关行业的充分重视。 论文对硬盘数字播控系统的一些关键技术进行了较为系统地分类研究和工程实验。 论文首先对视频广播行业数字化改造的现状与趋势进行综述，重点讨论了数字播控所涉及的若干关键技术的概况，包括数字压缩编解码技术、海量存储与容错技术、网络互连技术和系统安全备份播出技术等，并对电视节目的制、编、播一体化网络进行展望。 然后，论文实现了基于软件方式的MPEG-2标准视频及AC-3格式压缩音频的实时解码与回放，并依据MPEG-2系统解码模型 实现了一种基于音频基准时钟的MPEG解码器的视音频同步算法，实验证明该算法可行、实用、通用性好，对符合MPEG-1或MPEG-2系统标准的视音频解码器均具适用性。同时，该算法也对MPEG硬件解码器及其他多路复用格式的视音频解压具有借鉴价值。 论文以双机热备安全播出系统的研究为背景，提出并仿真实现了一种基于数字媒体参考信息的双机备份同步播出算法。该算法充分利用被播媒体本身的数字化位置信息作为播出进度同步的参考，广泛的支持多种格式数字媒体。算法复杂度低，通用性强，并有效利用播出工作站的串行接口资源，无需特殊硬件的支持，软件实验仿真成功有效。 论文还系统地阐述了基于事件驱动的多媒体同步与链接机制的原理与实现技术，并成功地应用在电视节目自动播控系统软件的设计中。该技术模块化基于面向对象的设计思想，并且具有较好的通用性、灵活控制性和扩展能力。 最后，论文讨论了RAID技术的基本原理和应用策略，并推导了一系列基于RAID磁盘阵列可靠性理论的公式，为有效评价RAID技术的可用性提供了一定的理论依据。 论文研究成果为全数字多通道播出系统及其相关技术的深入研究奠定了扎实的技术理论基础，具有较高的实用价值，部分已成功应用于项目的实际开发，并已形成商业化产品。更多还原

【Abstract】 Traditional technology on playing out TV programs focuses on VTR,therefore,it is called tape-based TV broadcasting mode. With the development of digital information technology,DVB comes into being. Hard disk automatic Digital Playing-out and Control Systems ( DPCS ) are the current hot issue in the field of TV broadcasting. This subject is built upon a good many kernel and key technic,each of which is a significant subject in theory and application. Based on this background,the research in the technic of DPCS on audio & video (AV) is put forward,which has been emphasized by international academe and enterprise at the present time.This dissertation has studied some key technologies in the field of DPCS on AV.First,this dissertation gives a summarize about the development status of the alteration and upgrade in the TV broadcasting system,in which a serious of key technologies of DPCS,including digital compression codec technology,large capacity storage and fault-tolerance technology,network connection technology,and systems security mode,are stressed.Second,this dissertation implements separately a MPEG-2 video decoder and a Dolby AC-3 digital audio decoder based on software mode,and gives a audio & video synchronization algorithm based on audio-clock-benchmark in MPEG-2 system decoder,whose feasibility and practicability have been proved by experimenting. It is an all-purpose algorithm,which can perform different decoder according to MPEG-1 or MPEG-2 system models,and can also be used for reference to the implementation of other multiplex stream decoders.Thirdly,this dissertation gives a Synchronization algorithm of double work-stations’ playing out based on digital reference information. This algorithm can support multiform digital medias,which take advantages of the serial-ports and socket resource effectively. The successful simulate implementation proved its feasibility.Fourthly,this dissertation expatiates the principium and implementation of multimedia synchronization & chaining mechanism based on event-driven,and applies it in the project of DPCS software practically. This method leads to more flexible control,expansibility and friendly user interface based on the thought of object oriented.At last,this dissertation discusses the principium and application of RAID technology,and concludes a serious of theoretic expressions in order to support a justified evaluating system of the reliability of RAID.更多还原