Open graphical framework for interactive TV

Multimedia end-user terminals are expected to perform advanced user interface related tasks. These tasks are carried out by user interface runtime tools and include, among others, the visualization of complex graphics and the efficient handling of user input. In addition, the terminal´s graphical system is expected, for example, to be able to synchronize audio and video, and control different contexts on the same screen. Finally, the availability of high level tools to simplify the user interface implementation and the adaptiveness of the user interfaces for a diversity of configurations are, as well, desirable features. We present a layered model that meets the just mentioned requirements. The architecture is divided into five different layers: hardware abstraction layer, multimedia cross platform libraries, graphical environment, GUI toolkit and high level languages. Moreover, a prototype system based on the architecture, targeted to digital television receivers, was implemented for the purpose of testing the validity of the concepts. In order to evaluate the prototype, some already developed MHP compliant digital television applications were tested. In addition the prototype was extended with a high level profile(i.e., SMIL support) and a low level one, (i.e., access to the frame buffer memory).