This thesis is focused on the authoring process of object-based AV applications according to the object and scene concept of MPEG-4. The object-based approach embraces the extended interactive opportunities of multimedia applications as well as the distribution opportunities of audiovisual media. Producing of object-based AV applications has profound effects on the whole digital media chain. The existence of efficient authoring tools and systems is an important requirement for the success of such applications. The goal of this work was the development of concepts and components for an authoring system for object-based AV applications that supports collaborative work of several authors. The development was divided into three fields: authoring formats, authoring servers, and authoring tools. Authoring formats store all of the resulting information for the description of object-based AV applications during the authoring process. They describe a scene on a well adapted abstraction level and enable the exchange of scene data with other authors and systems. Some special authoring formats were developed which fulfill the requirements of concrete applications regarding abstraction level and function range. Authoring tools are the interfaces of the authoring system to the authors. In focus are interactive graphic tools for the support of an intuitive work during the authoring process. The authoring server is the technical basis for the collaborative work of several authors in the production of object-based AV applications. A flexible data management was developed on the basis of a native XML database. It controls the access at the level of nodes within the scene graph and enables the collaboration of many authors in a novel way. The authoring server is also the interface between the producers of media objects and the authors. Furthermore, it enables the reusability of scenes and elements in different projects. The developed concepts are oriented towards the possibilities of MPEG-4, but they are transferable to other multimedia applications which are based on a scene graph. With these concepts and components both can be realized, universally applicable as well as specialized authoring systems and tools. Several exemplary applications show the operability of the developed components.
Die vorliegende Dissertation beschäftigt sich mit dem Authoring-Prozess objektbasierter AV-Anwendungen auf Basis des Objekt- und Szenenkonzeptes von MPEG-4. Diese moderne Beschreibungsform vereint die interaktiven Nutzungsmöglichkeiten digitaler Medien mit den Distributionsmöglichkeiten audiovisueller Medien. Die Umsetzung des Objekt- und Szenenkonzeptes hat tief greifende Auswirkungen auf die gesamte digitale Medienkette. Die Schaffung leistungsfähiger Autorensysteme ist eine wichtige Voraussetzung für die Verbreitung solcher Anwendungen.