Department of Computer Science and Technology

Technical reports

Multipoint digital video communications

Xiaofeng Jiang

April 1992, 124 pages

This technical report is based on a dissertation submitted December 1991 by the author for the degree of Doctor of Philosophy to the University of Cambridge, Wolfson College.

DOI: 10.48456/tr-251


Ever since the emergence of high-speed communication networks and fast signal processing technology, digital video has been attracting increased research interest. However, problems associated with its use in a multipoint communication environment have not been thouroughly investigated. In particular, these include the avoidance of congestion on multicast paths when multiple wideband sources are transmitting simultaneously, and the ability to interchange different format signals properly and efficiently. This dissertation addresses these issues with a two-level communications architecture.

The congestion issue at the network level is dealt with by several stream multicast path finding algorithms which are either centralised or distributed to suit various application environments. Different ways of integrating communication link capacities are investigated for supporting simultaneous transmission of broadband signals with minimum effect on network traffic and maximum success in path finding. Simulation results demonstrate performance improvements over conventional multicast path finding algorithms.

The format issue at the presentation level is dealt with by an intermediate format or general representation of digital video streams. Signals under this scheme are organised in a form to facilitate their interchange and scalable receiving in multipoint communication applications. Issues including frame segmentation and coding description are investigated. An experimental system implementing a simple version of the scheme is presented along with test results on picture quality degredation from conversion of various types and related timing characteristics.

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BibTeX record

  author =	 {Jiang, Xiaofeng},
  title = 	 {{Multipoint digital video communications}},
  year = 	 1992,
  month = 	 apr,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-251},
  number = 	 {UCAM-CL-TR-251}