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A CORBA Compliant Real-Time Multimedia Platform for

Broadband Networks

G. Coulson and D. G. Waddington

Distributed Multimedia Research Group,
Computing Department,
Lancaster University,
Lancaster LA1 4YR,
UK

e-mail: [geoff,dan]@comp.lancs .ac.uk

ABSTRACT

We describe the architecture of a CORBA-based platform offering end-to-end multimedia communications and processing support in a broadband network environment. The design gives application programmers an extended CORBA computational model incorporating explicit support for continuous media including quality of service abstractions. The proposed architecture goes beyond existing multimedia-in-CORBA platforms by integrating continuous media data types as first class types in the application programmer?s computational model. This is in contrast to currently proposed platforms which typically adopt an ?off line plumbing? approach where application programmers connect together ?standard? multimedia objects and then monitor and control the flow of media inside these objects. We present our extensions in detail using code examples based on Iona?s Orbix CORBA 2.0 compliant platform. We also offer a scenario illustrating the use of our extensions and the implementation of a simple binding object.

1. INTRODUCTION

This paper describes the architecture of a CORBA-based platform offering end-to-end multimedia communications and processing support in a broadband network environment. The design gives application programmers an extended CORBA computational model incorporating explicit support for continuous media like digital audio and video, including quality of service (QoS) abstractions.

The proposed architecture goes beyond existing multimedia-in-CORBA platforms (e.g. the IMA?s MSS [IMA,96], Columbia?s Xbind [Aurrecoechea,96] or Sandia?s DAVE [Mines,94]) by integrating continuous media data types as first class types in the application programmer?s computational model. This is in contrast to currently proposed platforms which typically adopt an ?off line plumbing? approach: application programmers connect together ?standard? multimedia objects (e.g. source and sink devices, processing objects, communication objects, etc.), and then monitor and control the flow of media inside these objects. In such platforms, application programmers are not expected to require access to the internals of the standard objects; these are written by systems programmers and provided to the application writer in the form of libraries.