An important challenge for supporting multimedia applications in heterogeneous networks is the heterogeneity of fixed and mobile access networks. In this work, we design a new and efficient context-aware middleware for facilitating diverse multimedia services in heterogeneous networks environment. Firstly, we present an adaptive service provisioning middleware for handling the heterogeneity of diverse networks and enable service provisioning to mobile users and professionals anywhere, anytime. Then, a context-aware multimedia middleware framework is presented based on the proposed adaptive service provisioning framework to support diverse multimedia services, including, multimedia content filtering, recommendation, adaptation, aggregation, learning, reasoning, and delivery. To the best of knowledge, this study is the first one to provide a general heterogeneous multimedia middleware by jointly considering the characteristics of context-multimedia service and heterogeneous networks.