The link vs. the event: activating and deactivating elements in time-based hypermedia

Abstract

Activation and deactivation of media items plays a fundamental role in the playing of multimedia and time-based hypermedia presentations. Activation and deactivation information thus has to be captured in an underlying document format. In this paper we show that a number of aspects of activation and deactivation information can be captured using both link structures and events in time-based hypermedia. In particular, we discuss how deactivation and activation can be specified, how the activations and deactivations can be initiated and potential (synchronization) relationships between the elements involved. We first introduce the notions of time-based scheduling and event-based scheduling and then present a short summary of linking. We discuss the similarities between event-based scheduling and linking. We describe a number of aspects of activation and deactivation that can be specified within a document. We then discuss how activation and deactivation information can be recorded in link structures and events.

The end-point is not enough

“…Such a trigger would be used for the previous example of continously updating a display while a video clip is playing. The trigger is presented upon reaching the This allows synchronisation as discussed in [7].…”

Advene

“…The rationale for this choice is that we aim at user accessibility: scheduled views are more programmer-oriented, and the event-based approach is well suited to highly interactive hypermedia [13]. Our use of ECA-rules is not meant as a full-fledged composition language, but as a simple means to achieve goals expressed by the users, using an understandable model.…”

Formalismes de manipulation du temps par l'auteur dans les documents multimédias

“…D'un point de vue temporel, au moment de la restitution, sont à prendre en compte la réactivité interne concernant l'interaction entre composants et la réactivité externe liée à l'interaction de l'utilisateur avec les composants. La réactivité externe peut concerner une action directe sur un média pour en interrompre la restitution, ou de façon générale la manipuler, ou même déclencher des enchaînements liés au parcours de liens lorsque les documents sont hypermédias (Hardman, 2000). En résumé un document multimédia est un document structuré qui implique plusieurs médias pour sa restitution, dont l'un au moins est un médium continu.…”