Eva Rosdiana
Title of thesis : Transmission of Transcoded Video over ABR Networks
Position: Student/Research Assistant
Degree awarded Master of Science by Dissertation (MSD)
Duration of study Oct 1998 – April 2000
Financial support British Telecom
Supervisor Prof. M. Ghanbari
Current affiliation
Eva Rosdiana
Lecturer
Electronic and Computer Engineering Division
School of Engineering
Ngee Ann Polytechnic
535 Clementi Road
Singapore 599489
DID: (65) 6460-8289
E-mail: rev@np.edu.sg
www.np.edu.sg
Abstract
In transmission of bursty traffic such as video and data, a fixed-capacity network may
have some unused bandwidth. By exploiting the intelligence of the network, this extra
bandwidth with variable capacity can be utilised for other lower priority services. To
do so, the network relies on a mechanism to periodically update the amount of
available channel bandwidth and informs the sources of the allowable transmission
rates. One standard that employs this concept is the Available Bit Rate (ABR) scheme
in ATM networks which has been developed initially for delay-tolerant services such
as data. In this thesis, we demonstrate how with the help of a video transcoder, delaysensitive services such as video may be transmitted over ABR networks. For ABR
video services to be practical, the picture quality of the ABR video must be
acceptable. The transcoder used in this context further compresses the video bit
stream according to the rates dictated by the network with minimum degradation of
the picture quality. We have also optimised the video quality by combining the
classical Minimum Cell Rate (MCR) with the Subjectively Acceptable Minimum
Quality (SAMQ). The performance of two different coding formats for ABR sources,
namely the Constant Bit Rate (CBR) and Variable Bit Rate (VBR) video input to the
transcoder are compared. Techniques for further reduction of congestion at the
multiplexing switches are also presented. We also investigate the impact of the
forward and backward link delays on the ABR scheme with the video transcoder.
Finally, a novel rate allocation algorithm is devised to distribute the available
bandwidth among the ABR video sources sharing the same channel. It is shown that
by allocating the leftover bandwidth to the sources based on the picture complexity,
one can optimise the utilisation of network resources and produce fair picture quality
for all the contending sources.
Publications
Journal papers
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E. ROSDIANA and M. GHANBARI, ‘A Picture Complexity Based Rate
Allocation Algorithm for Transcoded Video over ABR Networks’, IEE
Electronic Letters, vol. 36, no. 6, pp. 521-522, 16 March 2000
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E. ROSDIANA and M. GHANBARI, ‘Minimum cell queuing delay with
optimised ABR video quality’, EE Electronic Letters, vol. 36, no. 13, pp.
1160-1161, 22 June 2000
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E. ROSDIANA, H. AZMOODEH and M. GHANBARI, ‘Congestion
Reduction in Transmission of Video over ABR Networks’, IEE Proceedings
on Communications, 147:6, (December 2000), pp. 305-310.
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E. ROSDIANA, H. AZMOODEH and M. GHANBARI, ‘Picture Quality
Optimization in ABR Services’, Signal Processing: Image Communications,
Special issue on Packet video Communications, Vol16, No 8, (May 2001), pp.
733-744.
Patent
M. Ghanbari with M. Azmoodeh and E. Rosdiana, “Video transmission”
International Patent, WO 01/39508 A1, publication date May 31, 2001.
Conference papers
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E. ROSDIANA and M. GHANBARI, ‘Subjective determination of MCR in ABR
video’, presented at the 9th International Packet Video Workshop 99, New
York, USA, April 1999
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E. ROSDIANA, H. AZMOODEH and M. GHANBARI, ‘Picture quality
optimisation in ABR video services’, presented at the 10th International
Packet Video Workshop 2000, 1-2 May 2000