Lowpass filtering of rate-distortion functions for quality smoothing for real-time video recording and streaming

In this work, we introduce the concept of low-pass filtering of rate-distortion (R-D) functions and develop a smoothed rate control (SRC) framework for real-time video recording and streaming. Theoretically, we prove that using a geometric averaging filter the SRC algorithm is able to maintain a very smooth video presentation quality while achieving the target bit rate automatically. The proposed SRC algorithm has very low computational complexity and implementation cost. Our extensive experimental results demonstrate that the proposed SRC algorithm significantly reduces the picture quality variation in the encoded video clips while matching the encoding bit rate target very accurately.