ActiveTimesheets: extending web-based multimedia documents with dynamic modification and reuse features

Methods for authoring Web-based multimedia presentations have advanced considerably with the improvements provided by HTML5. However, authors of these multimedia presentations still lack expressive, declarative language constructs to encode synchronized multimedia scenarios. The SMIL Timesheets language is a serious contender to tackle this problem as it provides alternatives to associate a declarative timing specification to an HTML document. However, in its current form, the SMIL Timesheets language does not meet important requirements observed in Web-based multimedia applications. In order to tackle this problem, this paper presents the ActiveTimesheets engine, which extends the SMIL Timesheets language by providing dynamic client-side modifications, temporal linking and reuse of temporal constructs in fine granularity. All these contributions are demonstrated in the context of a Web-based annotation and extension tool for multimedia documents.