This paper presents a novel frame-layer rate control technique that adaptively determines the frame complexity for bit allocation in order to satisfy the target bit-rate constraints without degrading the decoded video significantly. To do this, we first obtain the edge energy of each frame to measure the frame complexity as well as to determine the weighting of a frame for bit allocation. We then present a new bit-rate traffic model for bit allocation to achieve a better conformance to the target bit-rate. Finally, we integrate the edge energy complexity measure into the rate-quantization (R-Q) model. Our results shows robust improvements over the current rate control methods adopted in H.264/AVC in terms of meeting the target bit-rate as well as determining the quality of the decoded video.