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