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

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.

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.

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)

Media Element Time

Has own intrinsic duration.

E.g. Video clip, audio fragment

SMIL Attributes : clip-begin, clip-end

(synchronized multimedia integration language)

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

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.

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.

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.

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.

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.

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.

Discussion Session