Research & Application Of Streaming Media Service And Play Control In PIS

The construction of urban railway is booming in China.Traditionally, in the Passenger Information System(PIS),the multimedia and operation information are composed at control center,and then sent to platform device where the information is played.It is difficult for traditional urban railway system to update information and deal with emergency.At the same time,passengers put forward high demands for PIS services, therefore how to publicize information rapidly becomes one of the urgent problems for PIS.This paper presents an implemental approach of PIS based on the streaming media technology,concerning subsystems of streaming media service,load balancing of streaming media services,and controlling & playing passenger information.By researching the architecture of VLC, we addless a method to offer streaming media service in PIS.A novel load balancer supporting a lot of load balancing algorithms.is proposed in streaming media clustered system.A browser-based player,which could process service logically,is designed to control and play passenger information.Also the interaction,scheduling and playing of passenger information and other problems have been solved in this paper.The major researches are as following:1.Streaming media service.The commercial streaming media servers are lacking in cost,portability and customizability,so VLC which is an open source streaming media server & player is used to offer streaming media service in PIS.We propose the mechanisms of creating streaming media service in PIS by analysing the source code of VLC,summarizing the architecture of VLC,comparing the patterns of creating streaming media service and consummating the functions of VLC.Through hash functions,XML files and network transmissions,the VLC command data, management of command,interaction of command and other problems in streaming media service are also solved respectively.2.Load balancing of streaming media service.In order to gain high quality of streaming media service,streaming media clustered system is adopted.This paper brings forward a method to design the architecture of streaming media clustered system and studies the load balancer. Object-oriented method is used to design the load balancer which supports the framework of several kinds of load balancing algorithms, and its load balancing algorithms and streaming media servers are configured in XML files.3.Controlling & playing passenger information of PIS.By comparing the features between C/S and B/S and analysing the demands of urban railway,we design a browser-based player which holds the capability of processing service logically,including real-time scheduling algorithm and operation information updation.The information interacting between client player and Web server is transmitted through TCP/IP with XML files.The information of PIS is controlled by RMS which is a classic real-time scheduling algorithm.Streaming media is played in VLC plug-in.Urban railway passenger information is updated by executing javascript functions through COM.4.System implementation.In the end,several subsystems including streaming media service of PIS,load balancing of streaming media service,and controlling & playing passenger information are designed and realized.The project has gone into operation in Shanghai metro.The research approach is can be used not only in passenger information system of urban railway but also in other information diffusion fields such as hypermarket,hospital,university and so on.