Adaptive stopping strategies for fast intra mode decision in HEVC

Fast intra mode decision strategies are proposed to overcome the brute force mode decision for the coding unit (CU) in High Efficiency Video Coding (HEVC). The proposed work improves the rough-mode-decision (RMD) by initializing the candidate intra mode list using the fusion of the Hadamard-cost and the statistical-inference formed using spatial/ temporal correlations. Then an early termination is predicted using optimal stopping theory that addresses early decision for a generic class of decision problems. Subsequently, a novel RD-cost prediction model is developed for early termination that is based on the RD-cost variation in the neighboring CUs with-respect-to their co-located CUs. Experimental results demonstrate that the RMD module of HEVC and the state-of-the-art fast intra mode prediction published method are outperformed by saving up to 0.61% and 0.91% Bjontegaard delta bit rate (BDBR) on average, respectively.