Do You Have the Time? Composition and Linking in Time-based Hypermedia

1. Do You Have the Time? Composition and Linking in Time-based Hypermedia Lynda Hardman, Jacco van Ossenbruggen, K. Sjoerd Mullender, Lloyd Rutledge, and Dick C.S. Bulterman Presented By : Ananda Man Shrestha

2. Introduction • Time is dominant characteristic of multimedia presentations. • Need of support for temporal (presentation time) and linking aspects in hypermedia. • This paper reports new insights in the temporal and link activation aspects of a hypermedia presentation.

3. Presentation Time • Presentation : artifact the reader experiences during the course of playing a document. • Document : underlying storage representation. May be single or multiple file, or stored in database. • Presentation Time : The timing from the perspective of the presentation.

4. Presentation Time • Media Element Time (intrinsic time of media elems.) • The time it would take to play the media item on an ideal system. • Document Time (authors perspective) • The time the author can assign and manipulate within the presentation and can be stored in the document. • Rendered Time (system perspective) • Overall timing of document based upon users preference and system capabilities • RunTime (readers perspective) • Real time to play the presentation (network delay, reader interactions come into play)

5. Media Element Time • Has own intrinsic duration. • E.g. Video clip, audio fragment • SMIL Attributes : clip-begin, clip-end (synchronized multimedia integration language)

6. Document Time • Author assigned duration • E.g.Looping/stretching, cutting/ shrinking etc • Transition information: face in/out, special effects. • SMIL attributes : repeat, begin, end, duration. (synchronized multimedia integration language) • AHM (Amsterdam hypermedia model) • Supports atomic component duration and anchor duration. • Single Media Element Object

7. Document Time • Multiple Media Element Object • AHM : temporal composite (atomic components + temporal information) • Synchronization arcs : specify start time of destination component relative to source component.

8. Rendered Time • Presentation adapted to reader preference. • Different user languages. • Different system hardware, bandwidth etc • Provide alternative media elements. • Grouping of alternative components required. • No synchronization info required among children of the groups. • AHM : • Atemporal composite.

9. Runtime • 3 types of interaction at runtime. • Interaction within a single multimedia presentation. • Linking among linear multimedia presentations. • Linking within and among non-linear multimedia presentations.

10. Runtime • Interaction within a single multimedia presentation. • Using controls like pause/play, fast forward/backward • Using predefined links. Destination anchor is in the same multimedia presentation.

11. Runtime • Linking among linear multimedia presentations. • What happens to source presentation? • Options : continue, pause or replace. • SMIL • Show attribute : replace, new and pause value. • AHM • Replace , new, pause option • Link also contain activation states : destination presentation to start in play/pause mode.

12. Runtime • Linking within and among non-linear multimedia presentations. • Reading the text while playing music/video on the background. • SMIL : This behavior cannot be expressed. • AHM : This behavior can be expressed using atemporal composition.

13. Discussion Session