Adaptive scheduling of multimedia documents

Multimedia presentations are applicable in various domains such as advertising, commercial presentations or education. Multimedia presentations are described by multimedia documents. The presentation of multimedia documents require vast system resources due to the huge amount of data that has to be transferred and processed by the computer system. If multimedia documents can be accessed on-line via different types of networks and be presented on various types of terminals, such as PCs or Set-Top-Units, different amounts of resources may be available at presentation time. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification. For usual multimedia documents resource scarcity implies an arbitrarily reduced quality of the presentation or it can even be impossible to start or continue the presentation. To handle resource scarcity in a better way, multimedia documents can be specified flexible so that they can be adapted to different resource situations. Our temporal model provides abstractions to specify flexible multimedia documents on two levels. It is possible to specify multimedia documents with alternative presentation parts. Further on, the presentation behavior of media objects can vary within specified limits. Hence, the temporal model allows to compose presentations which have a defined behavior when resource restrictions occur. The presented adaptive scheduling algorithm uses the flexibility in specifications to adapt presentations at regular intervals to the current resource situation. Hence, the quality of presentations is reduced or increased in a defined manner

Specification and scheduling of adaptive multimedia documents

Multimedia documents are of importance in several application areas, such as education, training, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification, resulting in a reduced presentation quality, if the presentation is possible at all. To cope with those situations, different versions of the same document can be specified, one for each potential configuration or probable load situation. A better approach is to have only one document that can be adapted to different system configurations and load conditions. To enable this approach, an adaptive document model as well as an adaptive scheduling algorithm are necessary. In this paper, we present the adaptive Tiempo document model, an algorithm to check the consistency of specifications, the concepts of a graphical document editor supporting the model as well as a scheduling algorithm which allows to adapt documents conform to our model in environments with best-effort assignment of resources

TIEMPO: an authoring and presentation system for interactive multimedia

The composition of interactive multimedia titles is a challenge for all advanced multimedia authoring tools. When non-interactive titles were specified by aligning the media items on a temporal axis such as time lines or tracks, now interactive multimedia titles require a non-linear temporal model. Thus, authoring becomes more complex, and the structure of a title is more difficult to visualize. TIEMPO addresses two areas: First, a temporal model satisfying the specification needs of interactive multimedia; Secondly, an interface for easy and rapid authoring of multimedia titles. This paper presents the architecture and design principles of the TIEMPO authoring and presentation environment

Specification and Scheduling of Adaptive Multimedia Documents

24 pagesMultimedia documents are of importance in several application areas, such as education, training, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification, resulting in a reduced presentation quality, if the presentation is possible at all. To cope with those situations, different versions of the same document can be specified, one for each potential configuration or probable load situation. A better approach is to have only one document that can be adapted to different system configurations and load conditions. To enable this approach, an adaptive document model as well as an adaptive scheduling algorithm are necessary. In this paper, we present the adaptive Tiempo document model, an algorithm to check the consistency of specifications, the concepts of a graphical document editor supporting the model as well as a scheduling algorithm which allows to adapt documents conform to our model in environments with best-effort assignment of resources

Modeling and scheduling of adaptive multimedia-documents

Multimedia-Dokumente ermöglichen eine integrierte Präsentation diskreter und kontinuierlicher Medien. In einer verteilten Umgebung werden Multimedia-Dokumente typischerweise auf Servern gespeichert. Von dort können sie bei Bedarf abgerufen und präsentiert werden. Durch die enthaltenen kontinuierlichen Medien erfordert die Präsentation von Multimedia-Dokumenten viele Ressourcen, so daß schnell Ressourcenengpässe entstehen, wodurch es unmöglich wird ein Multimedia-Dokument wie spezifiziert zu präsentieren. Das Resultat ist eine reduzierte Präsentationsqualität und manchmal kann es sogar unmöglich werden ein Dokument zu präsentieren. Eine Lösung für dieses Problem bieten Multimedia-Dokumente, die sich an unterschiedliche Ressourcensituationen anpassen können. Adaptive Multimedia-Dokumente enthalten Präsentationsalternativen, die unterschiedliche Ressourcenanforderungen implizieren. Bei der Vorbereitung der Präsentation eines Multimedia-Dokuments wird dann eine geeignete Untermenge der Präsentationsalternativen unter Berücksichtigung der momentanen Ressourcensituation ausgewählt. In der Arbeit wird ein Modell für adaptive Multimedia-Dokumente vorgestellt und es werden Implikationen erörtert, die sich durch die Adaptivität in Bezug auf die Dokumenterstellung, die Konsistenzwahrung, die Ablaufplanung und die Architektur eines Dokumentensystems ergeben. Das entwickelte Dokumentenmodell integriert Abstraktionen zur Definition von alternativen Präsentationsmöglichkeiten sowie zur Steuerung der Auswahl von Präsentationsalternativen während der Präsentation. Der Schwerpunkt liegt hierbei auf der Modellierung adaptiver zeitlicher Aspekte. Da die Spezifikation von Präsentationsalternativen zu einer komplexeren Dokumentstruktur führt, wird ein graphisches Autorensystem erforderlich, das die Erstellung von adaptiven Multimedia-Dokumenten mittels visuellen Programmiertechniken ermöglicht. In der Arbeit wird ein Vorschlag für die Benutzerschnittstelle eines solchen Autorensystems erörtert. Dieses Konzept verwendet drei Ansichten, um die unterschiedlichen Aspekte eines adaptiven Multimedia-Dokuments zu visualisieren und zu erstellen. Eine komplexere Dokumentstruktur impliziert auch mehr Spezifikationsfehler. Es wurde daher ein automatischer Konsistenzprüfungsmechanismus entwickelt, der eine aufwendige und zeitintensive manuelle Fehlersuche vermeidet. Bevor ein Multimedia-Dokument präsentiert werden kann, muß das Präsentationssystem einen Ablaufplan erstellen, der beschreibt, wann welche Aktion durchgeführt werden muß, um eine Multimedia-Präsentation entsprechend dem Multimedia-Dokument zu erzeugen. Die Arbeit beschreibt einen adaptiven Ablaufplanungsalgorithmus, der die Ressourcensituation der Präsentationsumgebung bei der Erstellung von Ablaufplänen berücksichtigt. Der Algorithmus ermöglicht die Bestimmung der besten Kombination von Präsentationsalternativen, welche nicht mehr Ressourcen benötigt als verfügbar sind. Die vorgestellten Konzepte wurden prototypisch als Multimedia-Dokumentensystem implementiert, das über standardisierte Internet-Protokolle mit Dokument-Servern kommuniziert. Da die Nutzeranforderungen im Hinblick auf die Gestaltung von Multimedia-Dokumenten stetig wachsen, basiert das entwickelte Dokumentensystem auf einer Architektur, welche die Integration neuer Medientypen und Darstellungskonzepte für Medientypen unterstützt.Multimedia documents enable an orchestrated presentation of discrete and continuous media. In a distributed environment, multimedia documents are typically stored on servers from which they are retrieved for presentation. Since multimedia documents comprise continuous media, the presentation of those documents may require a significant amount of resources. Hence, it can happen that not enough resources are available to render a multimedia document according to the specification. The result is a reduced presentation quality and sometimes it can even be impossible to render a document. A solution for this problem provide multimedia documents which can be adapted to different resource situations. Adaptive multimedia documents contain presentation alternatives implying different resource requirements. When a multimedia document is prepared for presentation, an appropriate sub-set of presentation alternatives is selected taking account of the actual resource situation. The thesis presents a model for adaptive multimedia documents and discusses the effect of adaptability on document specification, document consistency, scheduling of presentations, and multimedia document system architecture. The developed document model integrates abstractions to define presentation alternatives and to control the selection of alternatives at presentation time. The model is focusing on adaptability in the temporal dimension. Since the specification of presentation alternatives increases the complexity of the document structure, a graphical authoring system is needed which allows to compose multimedia documents by visual programming techniques. The thesis presents a concept for the graphical user interface of such an authoring system. The concept comprises three views to visualize and edit the different aspects of an adaptive multimedia document. A more complex document structure implies also more specification errors. An automatic consistency checking algorithm was developed to avoid difficult and time-consuming manual error detection. Before a multimedia document can be rendered, the presentation system has to compile a schedule that describes which actions have to be performed to implement a multimedia presentation according to the multimedia document. The thesis describes an adaptive scheduling algorithm which considers the resource situation of the presentation environment when compiling schedules. The algorithm allows to determine the best combination of presentation alternatives that does not require more resources than available. The presented concepts have been implemented in a multimedia document system prototype which communicates via standardized internet protocols with document servers. Since user demands grow continuously with regard to the design of multimedia documents, the developed document system is based on an architecture that supports the integration of new media types and presentation concepts for media types

Adaptive Scheduling of Multimedia Documents

22 pagesMultimedia presentations are applicable in various domains such as advertising, commercial presentations or education. Multimedia presentations are described by multimedia documents. The presentation of multimedia documents require vast system resources due to the huge amount of data that has to be transferred and processed by the computer system. If multimedia documents can be accessed on-line via different types of networks and be presented on various types of terminals, such as PCs or Set-Top-Units, different amounts of resources may be available at presentation time. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification. For usual multimedia documents resource scarcity implies an arbitrarily reduced quality of the presentation or it can even be impossible to start or continue the presentation. To handle resource scarcity in a better way, multimedia documents can be specified flexible so that they can be adapted to different resource situations. Our temporal model provides abstractions to specify flexible multimedia documents on two levels. It is possible to specify multimedia documents with alternative presentation parts. Further on, the presentation behavior of media objects can vary within specified limits. Hence, the temporal model allows to compose presentations which have a defined behavior when resource restrictions occur. The presented adaptive scheduling algorithm uses the flexibility in specifications to adapt presentations at regular intervals to the current resource situation. Hence, the quality of presentations is reduced or increased in a defined manne

Abstract Specification and Scheduling of Adaptive Multimedia Documents

Multimedia documents are of importance in several application areas, such as education, training, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification, resulting in a reduced presentation quality, if the presentation is possible at all. To cope with those situations, different versions of the same document can be specified, one for each potential configuration or probable load situation. A better approach is to have only one document that can be adapted to different system configurations and load conditions. To enable this approach, an adaptive document model as well as an adaptive scheduling algorithm are necessary. In this paper, we present the adaptive Tiempo document model, an algorithm to check the consistency of specifications, the concepts of a graphical document editor supporting the model as well as a scheduling algorithm which allows to adapt documents conform to our model in environments with besteffort assignment of resources. 1

Adaptive Multimedia Documents

Multimedia documents are of importance in a wide range of application areas, such as education, training, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification, resulting in a reduced presentation quality, if the presentation is possible at all. To cope with those situations, different versions of the same document can be specified, one for each potential configuration or probable load situation. A better approach is to have only one document that can be adapted to different system configurations and load conditions. To enable this approach, multimedia documents have to be specified flexible so that different presentations can be compiled depending on the resource situation. In this paper, we analyse the adaptivity of multimedia documents and investigate to what extend existing document models support this type of adaptivity

Adaptive Multimedia Documents

Multimedia documents are of importance in a wide range of application areas, such as education, training, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification, resulting in a reduced presentation quality, if the presentation is possible at all. To cope with those situations, different versions of the same document can be specified, one for each potential configuration or probable load situation. A better approach is to have only one document that can be adapted to different system configurations and load conditions. To enable this approach, multimedia documents have to be specified flexible so that different presentations can be compiled depending on the resource situation. In this paper, we analyse the adaptivity of multimedia documents and investigate to what extend existing document models support this type of adaptivity

Modelling Interaction with HyTime

Interactive multimedia presentations are an essential issue in many advanced multimedia application tools. Before presenting multimedia data, media items, interaction types and synchronization constraints have to be specified in a multimedia document. This paper identifies and classifies the temporal interaction types in multimedia systems, and shows their impact on the specification process and the supporting system. Then, we describe how to specify the interaction types by using the standardized multimedia document language HyTime. The HyTime mechanisms are demonstrated by examples followed by a discussion of the advantages and limits of each technique. 1 Introduction With the emerging multimedia technologies, more and more application tools are developed to process and present multimedia data. Generally, multimedia data are stored as multimedia or hypermedia documents using a proprietary format [Appl91], [BuZe93], [BHL91], [LiGh90]. The result is that tools of different vendors or ..