The Nvod Video Server Design And Implementation

NVOD Video Server is the key part in the NVOD(Near Video-on-demand) system to realize NVOD services.It can automatically schedule NVOD program listings, store program information and entity information, complete the program stream multiplexing and transfer them,and so on.It can also determine the merits of the NVOD system performance. NVOD video server refers to digital television technology, network technology, multimedia technology, database technology and other technologies.Thus, it has a strong application and research value.Firstly,this paper started various digital television systems and video on demand (VOD) services in two ways: TVOD, and NVOD, then introduced the research significance of the NVOD Video Server.Because digital television standard is the core of the digital television technology, on which the design and implementation of all digital television business is based.the paper analyzed the various streams (ES, PES, PS, TS) structure in the MPEG-2 system part used by DVB and specified the relationships between them.And also described the concept of MPEG-2 program multiplexing and channel multiplexing;In the next, described the theory of Near Vide on Demand (NVOD) systems.Then, we planned the composition of NVOD system , made the tasks of NVOD video server (the control server and the broadcast server) clear, and completed the system general design.Then, the paper detailed the key to achieve NVOD services - the structure and meaning of some important descriptors of SDT and EIT tables in DVB's SI information ,we took an advanced modern software process (GRAPPLE) to the idea of NVOD broadcast control server design and implementation, used the thought of object-oriented design, made models in all stages of design using the UML language ,realized it at last.broadcast control server.Further down, we used the traditional process-oriented idea, designed and implemented the NVOD broadcast server modularly,in which we used a variable-rate (VBR) dynamic multiplexing algorithms, and specified the principle of the algorithm in detail, then, we multiplexed more than one single transport stream (SPTS) with different rates directly into one multi-program transport stream (MPTS) and sent it to the network process in the program. Finally,we showed some parts of the NVOD server.This paper designed the NVOD business and the broadcast of audio and video independently. Broadcast Control Server can also be used in other businesses after making a change, Broadcast Server can not only be used in NVOD system but alse be used in other digital TV by modification.