Mutually compensatory property of multimedia QoS

This paper studies user–level (or perceptual) QoS for multimedia applications over the Internet and demonstrates that media can compensate for each other from a perceptual point of view. For this study, we formulate the problem of the mutually compensatory property in terms of QoS mapping relation between application–level and user–level; we then conduct a simple experiment on lip synchronization to investigate the property. As a result, we observe the existence of the mutually compensatory property between voice and video. It is also shown that the property exists within a limited range of combinations of application–level QoS parameters. Furthermore, we point out the advantage of QoS control utilizing the property.