| Real-time playing system is the core part of the DTV system. Based on the DTV middleware platform, this paper designs and implements a DTV-oriented real-time playing system, which implements the real-time playing and control fuctions of DTV programs, and provides users with a wealth of information.Based on the demand analysis of the real-time playing system, the system is divided into four parts: Server Control Software, SI Engine, Media Player and EPG (Electronic Program Guide). This paper's main work is to design and implement the later three parts.SI Engines is an important part of the real-time playing system, which provides the applications with the service information (SI) support. Studing the transfer protocol, DTV transport stream (TS) and SI, a SI Engine is designed and implemented. SI Engine receives and parses the TS from the network, and creates SI database to store the SI extracted from the TS, and provides access interfaces.Media Player is the core part of the real-time playing system. This paper studies the principle of Xilleon220 in the set-top board, ATI component library, the media playing technology and script-driven mechanism of the mxtest application, then designs a Media Player, which implements the real-time playing and control functions of DTV programs, and provides the DTV applications with the media control APIs. As to the two deficiencies, mxtest application needs special SI to carry out and can only support no more than two programs, this paper uses the method of creating a script dynamically with the SI obtained from the SI database, and the method of extend the data struct and programs of mxtest application to solve the problems.EPG is a typical application in the DTV system.Based on the above work, an EPG is designed and implemented, which displays the SI obtained from SI database by the graphical interface, and monitors the operation from the user. EPG will call the associated media control APIs of the Media Player to response the user's operation.At the end of this paper, a function and performance test of the DTV real-time playing system is launched, and the results show good performance and strong function. |
