This paper describes the Hypermedia Presentation and Authoring System
(HPAS), a Web browser with built-in authoring capabilities. In contras
t to traditional browsers, it manages time-based hypermedia presentati
ons and the associated dynamic spatial layout with respect to time. Th
e system manipulates various media types by embedding object presenter
s, editors, and converters, which combine to provide transparent opera
tions on hypermedia objects, such as MPEG videos, GIF images, rich tex
t files, etc. (C) 1997 Published by Elsevier Science B.V.