It is an enhanced and extended version of 
A perceptual quality model intended for adaptive VoIP applications†
Article first published online: 14 NOV 2005
Copyright © 2005 John Wiley & Sons, Ltd.
International Journal of Communication Systems
Volume 19, Issue 3, pages 299–316, April 2006
How to Cite
Hoene, C., Karl, H. and Wolisz, A. (2006), A perceptual quality model intended for adaptive VoIP applications. Int. J. Commun. Syst., 19: 299–316. doi: 10.1002/dac.755
- Issue published online: 3 MAR 2006
- Article first published online: 14 NOV 2005
- Manuscript Accepted: 8 JUN 2005
- Manuscript Revised: 2 JUN 2005
- Manuscript Received: 30 SEP 2004
- Deutsche Forschungsgemeinschaft
- Internet telephony;
- adaptive transmission;
- perceptual quality model;
- delay spikes
Quality models predict the perceptual quality of services as they calculate subjective ratings from measured parameters. In this article, we present a new quality model that evaluates Voice over IP (VoIP) telephone calls. In addition to packet loss rate, coding mode and delay, it takes into account the impairments due to changes in the transmission configuration (e.g. switching the coding mode or re-scheduling the playout time). Moreover, this model can be used at run time to control the transmission of such calls. It is also computationally efficient and open source.
To demonstrate the potential of our model, we apply it to select the ideal coding and packet rate in bandwidth-limited environments. Furthermore, we decide, based on model predictions, whether to delay the playout of speech frames after delay spikes. Delay spikes often occur after congestion and cause packets to arrive too late. We show a considerable improvement in perceptual speech quality if our model is applied to control VoIP transmissions. Copyright © 2005 John Wiley & Sons, Ltd.