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

Abstract

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.INDEX TERMS Adaptive loop filter (ALF), super-block coding, ultra high-definition video coding.

An efficient post-processing adaptive filtering technique to rectifying the flickering effects

“…Due to a one-dimensional filtering approach, the in-loop processing method enhances the coding efficiency by reducing blocking artifacts amongst adjoining pixels or frames but is unable to process corner outliers. To alleviate blocking artifacts different post-processing approaches such as frequency domain analysis , Projection Onto Convex Sets (POCS) [9][10][11][12][13], waveletbased techniques [8,[20][21][22][23][24][25][26][27][28][29][30], estimation theory [5,[9][10][11][12][13], and filtering approach [11][12][13][14][15] has been proposed in last few decades. The most common method is to apply a low-pass filter across block boundaries to remove artifacts.…”

“…Filtration methods were initially developed by Wang P. et al [31] for the smooth region. Wang [24] also explained an adaptive filtering technique depending upon different frequency modes to remove blocking artifacts. On the other hand, corner outliers, detection, and removal have been proposed by [15,25].…”

“…On the other hand, corner outliers, detection, and removal have been proposed by [15,25]. During compression, the corner outlier pixels are either considerable value or very small value pixels concerning surrounding pixels [8,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Later on, Wang J. et al [37] presented an adaptive filter-based technique for compressed images of different regions.…”