This Recommendation describes a computational model for point-to-point interactive videophone applications over IP networks that is useful as a quality of experience (QoE)/ quality of service (QoS) planning tool for assessing the combined effects of variations in several video and speech parameters that affect the QoE. This model can be used by QoE/QoS planners to help ensure that users will be satisfied with end-to-end service quality. Actually, they want to avoid under-engineering. Network, application and terminal quality parameters of high importance to QoE/QoS planners are incorporated into this model.

The model provided in this Recommendation needs to be a flexible tool capable of providing feedback on individual qualities as well as overall quality.

This Recommendation is very different from [ITU-T J.148] in terms of input parameters. In this Recommendation, multimedia quality is calculated by using network, application and terminal equipment parameters, whereas in [ITU-T J.148], the calculation is done by using speech and video signals.

This Recommendation assumes videophone applications using dedicated videophone terminals, desktop PCs, laptop PCs, personal digital assistants (PDAs) and mobile phones. The speech bandwidth is limited to the telephone band (300-3400 Hz).

The application of this Recommendation is limited to QoE/QoS planning. Other applications such as quality benchmarking and monitoring are outside the scope of this Recommendation.