Rate control is very crucial for scalable video applications as it controls encoding bitrates so as to meet channel bandwidths while obtaining optimum encoding quality. In this paper, we proposed a new inter-layer rate control algorithm for H.264/SVC. One unique feature is that an effective switched model is proposed to predict the bit estimation used for encoding inter frames either from the previous frame of the current layer or from the current frame of the previous layer. In addition, this algorithm also develops a number of efficient rate control methods, including an extended Rate-Complexity-Quantization (R-C-Q) model, a robust Proportional + Integral + Derivative (PID) buffer controller, an effective inter-layer bit estimation approach. Our simulation results demonstrate that, our algorithm outperforms JVT-W043 rate control algorithm by providing more accurate output bit rate for each layer, maintaining more stable buffer fullness, reducing frame skipping and quality fluctuation, finally, improving the overall coding quality