Sparse-to-Dense: High Efficiency Rate Control for End-to-End Scale-Adaptive Video Coding

Traditional end-to-end video coding is typically featured with sparsely distributed operational rate-distortion (R-D) points. This creates daunting challenges to rate control which is typically regarded as the indispensable coding optimization module. To tackle this problem, this paper proposes high efficiency rate control for end-to-end scale-adaptive video coding which enables the conversion from sparsely to densely distributed R-D points. The proposed scheme does not increase the number of models in the sparse-to-dense conversion and provides more flexibility in end-to-end video coding thereby leading to better coding performance. More specifically, R-D analyses for scale-adaptive coding are first conducted, shedding light on the design of the rate control algorithm. Subsequently, generalized R-D models are presented, based on which high efficiency rate control is achieved. Extensive experimental results provide evidence of the efficiency of the proposed method in terms of R-D performance, control accuracy and computational complexity.