ABSTRACT
In order to enable transparent and augmented use of multimedia
resources across a wide range of networks and
devices, the forthcoming MPEG-21 standard aims at integrating
the various existing technologies for delivery and
consumption of digital content in a common multimedia
framework. Digital Item Adaptation is one of the core
concepts of the framework that will support the adaptation
of multimedia resources to device capabilities, underlying
network characteristics, or the user’s preferences.
The scope of the standardization, however, is limited to
the definition of description tools and does not deal with
the internals of the adaptation process itself.
In this paper, we first discuss the requirements of the resource
adaptation component of an adaptation engine.
These requirements include, for instance, openness for
the integration of external multimedia transforming tools
as well as intelligent decision taking when determining
the set of required adaptation steps. We also present a
prototype of a simple video resource adaptation engine
that completely relies on descriptions of the resource itself
(MPEG-7), the usage environment of the resource
(MPEG-21), as well as declarative descriptions of the
transformation tools. The prototype employs a knowledge-
based engine for finding and executing the needed
adaptation sequences.