Fine-Grained Region Adaptive Loop Filter for Super-Block Video Coding

In video coding, in-loop filter plays an essential role to reduce compression artifacts. This paper introduces a Fine-grained Region Adaptive Loop Filter (FR-ALF) approach for super-block coding based on the High Efficiency Video Coding (HEVC) framework. To address the over-smoothing and low-efficient problems, we introduce a flexible low-complexity FR-ALF method that achieves a finer granularity to control the filtering effect. Moreover, we design a new communication mechanism in order to avoid encoding the same overhead information. Experimental results show that compared with recent advances, our FR-ALF method achieves a satisfactory bit-rate saving by 2.76% on average, and consumes an affordable complexity increment.