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Journal of Computer Networks and Communications
Volume 2013, Article ID 351435, 13 pages
http://dx.doi.org/10.1155/2013/351435
Research Article

Estimation of Modelling Parameters for H.263-Quantized Video Traces

National Center for Scientific Research “DEMOKRITOS”, Institute of Informatics and Telecommunications, Agia Paraskevi, Attici, 15310 Athens, Greece

Received 28 December 2012; Revised 6 March 2013; Accepted 7 March 2013

Academic Editor: Rui Zhang

Copyright © 2013 A. Drigas and S. Kouremenos. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We propose methods for selecting the modelling parameters of H.263-quantized video traffic under two different encoding scenarios. For videos encoded with a constant quantization step (unconstrained), we conclude that a two-parameter power relation holds between the exhibited video bit rate and the quantizer value and that the autocorrelation decay rate remains constant for all cases. On the basis of these results, we propose a generic method for estimating the modelling parameters of unconstrained traffic by means of measuring the statistics of the single “raw” video trace. For rate-controlled video (constrained), we propose an approximate method based on the adjustment of the “shape” parameter of the counterpart—with respect to rate—unconstrained video trace. The convergence of the constructed models is assessed via q-q plots and queuing simulations. On the assumption that the popular MPEG-4 encoders like XVID, DIVX usually employ identical H.263 quantization and rate control schemes, it is expected that the results of this paper also hold for the MPEG-4 part 2 family.