Design And Implementation Of Digital Set-top Boxes Broadcast Browser

The development of information and communication technology greatly affects and changes people's lives, and also promotes the development of digital television. Data broadcasting is a relatively new digital TV service in China which can be used as a value-added service in digital TV system. Digital TV program, which is assembled from image, text, voice and etc, will be broadcasted via satellite. As the content of data broadcasting gets richer and richer, there will be a very good development prospect for DBS (data broadcasting services) in the future.This subject derives from the ABS (Advanced broadcast satellite) system projects of radio and television broadcast services of China. STi5107 which is provided by ST (STMicrotronics) is adopted as base chip and ST20 is selected as software development platform in this system. According to the relevant specification of the transmission of data broadcast and display in "every village" project, a broadcast browser which combines with data filtering and display features has been designed and finally implemented in this project.This paper firstly introduced the status and the development of embedded browser of set-top box. The PSI / SI information in MPEG-2 and DVB, XML syntax and XML parser are also briefly introduced in this part. Based on the request of this subject and the design proposal of data broadcast browser, the design process and implementation of each module are described in detail: with STi5107 chip hardware filtering features, design and implement the data–acquiring module for special information, prepare for the realization of XML parser. Secondly accomplish the pre-processing of XML document, including lexical analysis. Lexical analysis is to separate XML document into a single objects (such as element, attribute and etc.), and prepare for building a DOM tree. Syntax analysis, which checks the compliance of documents with the relevant XML grammar rules, is performed at the same time, then build the DOM tree corresponding to the XML document in memory. Finally, according to the DOM Level 3 Core specification, accomplish the relevant DOM interface. The application program could operate the DOM tree (including searching, inserting, deleting and etc.) through the DOM interface. Prepare for obtaining useful data in XML documents by this DOM parser. By studying the revelation principle of the character dot-matrix and still images, the browser display interface and its simple optimization has been accomplished combining with graphics chip features.