The Design And Implementation Of Graphic System In Software Architecture On Set Top Box

Following the comprehensive digitalization of television broadcast, achieving abundant utilization of digital TV business by using"Set Top Box"was now becoming a new and hot development area. The core technology of television interactive applications based on Middleware techniques was so called"Set Top Box graphics system". Currently, the traditional embedded graphic system could not optimize digitalized telecast, therefore, it would not support any operational performances through digital TV.According to various requirements on Digital TV application, we've developed a highly targeted Set Top Box graphic system based upon the middle layer of Set Top Box software hierarchy. During the process of designing, an updated graphic system design proposal and hierarchy has been raised up after analyzing the functional needs of system as well as the current principal graphic library. It would better fit the requirements of set top box software. On the basis of this proposal, we've completed the most important module within graphic system as well as the implementation of application manager, window manager, graphics interface definition, resource manager, media player. Such graphic system owns a certain degree of innovation and creation. First of all, the application manager was the focused design based on utilization of set top box, which also acted as a tool to centralize the management of complicated set top box execution. The application manager can not only supply unified management of application, but also can switch quickly in different applications. It is also able to handle kinds of interrupts from external part and the response process to the application. The window manager is responsible for windowing managing the presentation of utilization as well as optimizing the storage allocation against the windowing feature of set top box. An application is composed of several windows, then the window manages the control on the application. For a variety of applications, the window when allocating memory for set-top box applications and the characteristics of the window to allocate memory algorithms specially optimized. It prevents the frequent release of memory arising from memory fragmentation, greatly enhanced the stability of the application system. Another management of the resource file on set-top box also is unified managed by window manager, but there is a layer of graphics interface layer to control the basic drawing functions switching back and forth between the software decoding, hardware accelerated. The most distinguished character from other graphic systems was built-in the efficient management for fundamental function of set top box– i.e. playing. It is able to simultaneously support the playback from a variety of sources needs and is able to support in the platform encoding format of the video content comfortably. Players play by the underlying management and application-layer play, and introduce DVB sub-player in the design and implementation in detail, demonstrating the practical application of the player's performance.After moving the whole graphic system from design to actual scenario on hardware platform, we compared their performance on various platforms. Then we also successfully realized the execution of Set Top Box. It can meet the needs of digital TV application performances. In addition to that, we have also summarized some of the characteristics and weak points after so.