If outdoor positioning is widely treated and quite precise, indoor or more generally in heterogeneous environment, the positioning (and also mobility prediction) requires consequent devices. The WiFi solution, easy to deploy and cheaper, becomes today an alternative. Our refinement approach, which is based on, both a friis calibrated model and the referenced points, makes it competitive. The targeted applications require not only deployment and precision, but also diffusion of rich and interactive media flow. Keywords : Indoor Positioning, WiFi Network, Friis-based calibrated model, Model by Refinement, Media Guide, Middleware, Multimedia Platform.