A Novel Quality Enhanced Low Complexity Rate Control Algorithm for HEVC

Abstract

Rate control (RC) is a key technology in video coding which is mainly responsible for adapting the compressed video quality as much as possible under limited bandwidth. Typical RC methods consist of initial quantization parameters of I-frames decision and control parameters updating procedures. However, on the one hand, I-frames quantization parameter (QP) is decided by the sum of absolute transformed difference (SATD) computation, which is time consuming for low delay applications. On the other hand, the RC parameters are only updated ignoring the distortion characteristics for inter frame, which cannot achieve optimal rate distortion (RD) performance. Therefore, a novel RC method which considers distortion characteristics for model parameters updating for quality enhancement is proposed in this paper, including a low complexity based I-frame QP decision strategy of low delay applications. For which estimated distortion characteristics and the previous QPs are employed, respectively. Through the experimental results, with more accurate RC precision and negligible I-frame QP computation time, the proposed rate control scheme improves the performance gain of 2.6% bitrate savings for the whole test sequences on average in HM 16.9.