Fast coding unit size selection for HEVC based on Bayesian decision rule

Abstract

High Efficiency Video Coding (HEVC) is being developed by Joint Collaborative Team on Video Coding (JCT-VC). The new standard aims at a significant improvement on Rate Distortion (RD) performance over state-of-the-art video coding standards. Some new efficient coding tools are adopted, such as flexible data structure representation: Coding Unit (CU), Prediction Unit (PU), and Transform Unit (TU). Meanwhile, these new tools impose lots of complexity. We propose a CU size decision algorithm that greatly reduces the complexity of HEVC. The proposed algorithm collects relevant and computational-friendly features to assist decisions on CU splitting. To minimize the RD loss of the fast algorithm, a Bayesian decision rule is defined, based on which the encoder can save 41.4% encoding time on average (up to 66%) whilst suffers from negligible loss (1.88%) on RD performance.