Rate control for screen content coding based on picture classification

Emerging screen content coding brings great challenges to rate control due to significantly different characteristics of screen content from conventional video, e.g. large motion, frequent scene changes. This paper proposes an efficient rate control scheme for screen content coding by considering the characteristics of screen content. We first classify pictures of a video sequence into different groups by comparing the current picture with its neighbours. Then for each group, we apply different strategies to bit allocation and parameter updating process based on the characteristics of each group. The proposed algorithm can control the bitrate accurately without introducing any additional encoding delay. Experiment results show that the proposed scheme can significantly improve PSNR with a more accurate bitrate compared with the existing rate control scheme.