To guarantee the real-time transmission of a video stream,based on the stochastic optimal control method,a frame layer adaptive rate control algorithm for the wireless transcoder is proposed,which is capable of dynamically determining the transcoders objective bit rate,according to the bandwidth variation of the wireless channel and the bufier occupancy. Then the transient performance,steady performance,and computational complexity of the algorithm are analyzed.Finally,the experiment results demonstrate that the algorithm can improve the synthetic performance of rate control through the compromise between the end-to-end delay and the playout quality.