To improve the quality of experience (QoE) for video streaming services by avoiding frequent changes in the video quality, we propose a new quality control mechanism, called Smooth Rate-Smooth Quality Control (SR-SQC). The proposed scheme estimates the network status by using TFRC throughput equation, and then operates the smooth quality control based on the network status and the client buffer status. Through the smooth quality control, our scheme provides the adaptive streaming service according to the varying network status and improves the QoE by avoiding frequent changes in the video quality. Based on simulation results, we prove that our scheme can improve the QoE through smooth rate control and smooth quality control algorithms.