Design And Implementation Of VOD System In Digital Television

With the rapid development of information technology, the pace of information construction has been accelerated by economic globalization, advanced knowledge-based economy and intense market completion. Besides, the State Administration of Radio Film and Television (SARFT) proposed digitization and three networks convergence. The competition situation of TV changes from analog television system and network to digital TV, bilateral network and VOD (video on demand) step by step. The bilateral digital television VOD system has attracted more and more attentions. In recent years, the progress of digital television transformation and improvement of user’s appreciation level and aesthetic requirements demand higher quality bilateral VOD system. VOD system provides interactive video services through transmission network and user receiving device, and stores video program and other multimedia information in video server.In this paper, according to the existing mode of VOD system industry and analysis of system’s reliability, practicability, usability and manageability, a VOD system was designed based on digital television platform of Dandong Cable TV Network Company.Based on the in-depth study of existing media area storage technology and the most popular network storage technology, this paper applied NAS technology to design media area storage system, which is easy to system construction and suitable for multi-user access. For storage strategy, the file is stored in units of blocks, and reading and writing is managed separately. This system is able to solve the problems of VOD system of radio and television, which are large amount of video source and user access.With user’s more and more demand for VOD system, the increase load pressure of system will result in decline in the quality of service. To solve the load balancing problem of VOD system, this paper designed a hierarchical VOD system based on cache mode to improve the old distributed one. Comparing to several existing load balancing algorithms, the optimal proxy caching algorithm in this paper has advantage in the response of time.The system designed in this paper has been put into use in Dandong Cable Television network for one year after testing. This system operates stably and safely, and it has excellent performance and clear image.