Design And Implementation Of Embedded VOD System

With the rapid development of the network and multimedia technology,family multimedia,especially audio,video on demand services,has been more and more widely applied.At the same time,video on demand services has become an important part of information services.Video on demand(VOD) is characterized by users in selecting and viewing programs actively.According to personal preferences,people have a virtually free hand in watching their favorite programs on family media terminal.Protocol selection and implementation is an important technology of VOD system function implementation.For the features of streaming multimedia network broadcast system,this paper choose RTSP and RTP/RTCP protocol as the transport protocol,which also is versatile.Based on analysis of research background and application status of the key technologies of VOD system,according to the VOD business needs analysis,this paper mainly does the following work:(1) Through the analysis and extraction of common features of VOD service,the paper use a more rational and efficient VOD distributed system framework.And the results show that the VOD system used of the framework has relatively high efficientcy and preferable scalability;(2) According to analysis of user characteristics on internet,the paper improved the program scheduling strategy of VOD system server-side.Through analysis the VOD process,based on user behavior and program popularity,the paper put forward a design scheme,which is a combination of different fragments of each single program divided into pieces to be stored and realtime scheduling in different time;(3) Combined with RTSP and RTP/RTCP protocol.the paper achieved that video data is transmitted by RTP,video quality is controlled by the RTCP,and video control (play,pause,etc.) is executed by RTSP.At the same time,the paper achieve these communication session of these parts in the system design;(4) Based on ST7100 set-top box embedded hardware platform,combined with directshow theory and filter technology,the paper implement a VOD player terminal based on embedded devices.The paper did a lot of work and made detaile describe on the function design,software architecture design and the development of each corresponding module of VOD system,and also made a research on the data packet structure and analysis when the service-side and client are communicating.Centering on the VOD practicability and realtime requirement for system design,the method described in the paper have been in the actual use of VOD system,and showing a good service performance in accordance with the requirements of VOD services.