Structure-driven Adaptive Non-local Filter for High Efficiency Video Coding (HEVC)

Deblocking filter (DF) in High Efficiency Video Coding (HEVC) is only applied to all samples adjacent to prediction units (PU), or transform units (TU), which actually exists two issues. The first one is that DF in HEVC does not fully exploit nonlocal similarity structure information in video. The second one is that DF in HEVC does not consider the inside pixels, which often suffer from quantization distortion. To alleviate these issues, in this paper, a structure-driven adaptive non-local filter (SANF) is proposed by simultaneously enforcing the intrinsic local sparsity and the non-local self-similarity of each frame. Not only SANF deals with the boundary pixels, but also the inside area, which is able to effectively reduce block artifacts while enhancing the quality of the deblocked frames. Applying SANF to luma and chroma components after DF, simulation results demonstrate that the proposed SANF can save BD-rate reduction up to 10.3% with ALF off. For luma component, SANF achieves 4.1%, 3.3%, 4.4% BD-rate saving for all intra, low delay B and random access configurations, respectively with ALF off. Furthermore, the performance with ALF on is also discussed.