Interactive broadcast digital television. The OpenTV platform versus the MPEG-4 standard framework

The last years have seen a vast increase in interactive broadcast digital TV systems featuring proprietary platforms coupled with the standard MPEG-2. OpenTV is an example of a proprietary platform present on the market. The study of the OpenTV multimedia delivery framework and our involvement in MPEG-4 normalisation works give us the occasion to compare the OpenTV system architecture with the MPEG-4 one to address 2D interactivity in broadcast digital TV applications. We study their respective approaches to define 2D user interfaces and to manage dynamic interactive audio-visual content.