Media-Driven Dynamic Scene Adaptation

This paper presents a method to complement existing video, audio and image adaptation techniques in order to improve the perceived quality of interactive rich- media applications in streaming scenarios. This approach consists in dynamically adapting multimedia services at the presentation level according to media- level adaptation decisions. First, an enhanced decision-taking engine decides on the best presentation form based on author constraints. Then, presentation updates dynamically modify the user display according to fluctuating environment constraints. A fine-grain control of the synchronization of these updates with adapted media streams is used to enable seamless switching of media bitstreams with different coding (transcoding) or switching to media streams with different modality (transmoding). This paper finally describes an application test-bed using MPEG-4 and MPEG-21 to implement the proposed adaptation approach and illustrates the user experience improvement.