PID-based real-time rate control

Many existing rate control schemes consider spatial quality only. As a result, this may introduce a large distortion variation over frames to which people are sensitive. In fact, people are also sensitive to temporal quality. We design a real-time rate control based on a PID controller to have better tradeoff between spatial and temporal quality. From different estimated number of bits per frame and buffer status, different target bits for each frame are used in order to reduce the flickering effect (smaller distortion variation) which is one factor affecting temporal quality. Experimental results suggest that our scheme can obtain more consistent quality while keeping high spatial quality.