Abstract: In high efficiency video coding, the coding efficiency of I-frames is lower than P-frames and B-frames, causing flicker artifacts, especially in low bitrates applications. We propose a rate control algorithm for I-frames based on URQ model to improve the reconstruction quality of I-frames to suppress flicker artifacts. An I-frame is classified into three regions according to their motion vectors and complexity, termed motion region, texture-rich region and smooth region. According to different sensitivities of human visual system to different regions, visually sensitive regions are allocated more target bits. The URQ model is used to calculate QPs. Experimental results demonstrate that the proposed algorithm can efficiently suppress flicker artifacts and improve subjective and objective quality of the video.
 

Key words: URQ model, flicker suppression, I-frames, rate control