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