Abstract: A network-aware adaptive quality-of-service (QoS) framework for video transmission over heterogeneous wireless networks is presented. The whole framework and the adaptive QoS algorithm are described in detail. The framework mainly includes the scalable video coding module, the QoS mapping module, the bandwidth estimation module, the adaptive error, congestion control module, and decoder\output module. The optimized result is the minimum video distortion on the current network condition. The key advantages of the framework are:the error and congestion control mechanism in this framework is more effective, the perceptual quality is degraded gracefully when the network condition is severe, network resources are efficiently utilized. Simulation results demonstrate the performance improvement.