The Design And Implementation Of A Delivery And Scheduling System For Video Files

The main functions of video delivery and scheduling system are delivering the video files to servers according to certain rules, and scheduling videos on demand (VOD) from users to the server which can provide the best service. The delivery and scheduling system is the core part of a video website. It directly influences the service quality of video on demand for users on the video website. It functions as the foundat-ion of the video website. A video website has several requirements for the delivery and scheduling system of video files:high quality, easy to be deployed, easy to be ex-tended and high tolerance of disasters. High quality refers to accomodate huge amou-nt of user requests of VOD simultaneously. Easy to be deployed refers to that the ope-ration should be easy to deploy the system on thousands of servers. Easy to be exten-ded refers to that when the increase of video files exceed the capacity of the system, it is easy to extend the capacity through deploying new servers. High tolerance of disas-ters refers to that the failure of several servers should be jeopardize the normal operat-ion of the whole system.The main part of the thesis is to design and implement the delivery and scheduli-ng system for video files. The system mainly consists of three subsystems:cache sub-system, delivery subsystem and scheduling subsystem.The cache subsystem is constructed using open source software such as redis, ucarp, and mongodb, which satisfy the requirement such as high quality, huge capac-ity and high tolerance of disasters. This cache subsystem mainly stores the meta data, such as bit rates of video files, file locations, which are used by the other two subsys-tems.The main function of the delivery subsystem is to deliver video files to certain servers. It consists of the deliver global control program and the deliver client progr-am. The deliver global control program calculate the deliver tasks and deliver client program obtains deliver tasks and execute them.The main function of the scheduling subsystem is to schedule the request of VO-D from users to proper servers. It uses the open source software LVS and adopts kee- palived to achieve load balance. The scheduling algorithm adopts the nearby server principle scheduling algorithm based on users’ district and the service providers’ distr-ict.The delivery and scheduling system for video files has been successfully imple-mented and deployed on a video website. The one-cache rate achieves94%, which shows excellent performance.