Computer Laboratory

Technical reports

Presentation support for distributed multimedia applications

John Bates

June 1994, 140 pages


Distributed computing environments can now support digital continuous media (such as audio and video) in addition to still media (such as text and pictures). The work presented in this dissertation is motivated by the desire of application developers to create applications which utilise these multimedia environments. Many important application areas are emerging such as Computer-Aided Instruction (CAI) and Computer-Supported Cooperative Working (CSCW).

Building multimedia applications is currently a difficult and time consuming process. At run-time, an application must manage connections to a range of heterogeneous sevices to access data. Building applications directly on top of environment specific features roots them to those features. Continuous media introduces new problems into application management such as control of Quality of Service (QoS) and synchronisation of data items. An application may also be required to analyse, process or display data. Some multimedia applications are event-driven, i.e. they must perform actions in response to asynchronous run-time occurrences. They may also be required to control many workspaces and involve multiple users.

The thesis of this dissertation is based on two principles. Firstly, despite the heterogeneity between and within multimedia environments, that their functionality should be provided in a uniform way to application developers. By masking the control differences with generic abstractions, applications can easily be developed and ported. Secondly, that it is possible to develop such abstractions to support a wide range of multimedia applications. Extensible and configurable facilities can be provided to access, and present multimedia data and to support event-diven applications including cooperative ones.

The approach taken in this work is to provide a presentation support platform. To application developers this platform offers an authoring interface based on data modelling and specification using a script language. Using these facilities, the parts of an application involving interactive presentation of multimedia can be specified. Services have been built to support the run-time realisation of authored presentations on top of environments. Experiments show that a wide range of applications can be supported.

Full text

PS (0.8 MB)

BibTeX record

  author =	 {Bates, John},
  title = 	 {{Presentation support for distributed multimedia
  year = 	 1994,
  month = 	 jun,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  number = 	 {UCAM-CL-TR-341}