A special type of cooperative wireless transmission scheme is proposed for the broadcasting of scalable video sources. In the proposed system, a transmitter with multiple antennas sends out signals by encoding layered space-time codes. The receiver alone without cooperation can decode the base layer to get the basic quality of the video. For the cooperative terminals, with the help of relayed information, the enhanced layers can be retrieved and then the visual quality can be refined. Simulation results with video bitstreams encoded by H.264/scalable video coding show that the proposed system can enhance the scalable functionality of the video.