Temporal layer adaptive loop filter for HEVC

In this paper, we propose a temporal layer adaptive loop filter (TLAF), which suppresses the quantization noise adaptively to the characteristics of frames at different temporal layer. The proposed filter unifies two different modes of Kuan's filter which is an efficient linear minimum mean square error (LMMSE) estimator. Block-based non-local Kuan's filter (BNLK) is applied on frames at lower temporal layer in transform domain while pixel-based non-local Kuan's filter (PNLK) is applied on frames at higher temporal layer in spatial domain. Experimental results show that when compared with HEVC main profile, the proposed loop filter achieves on average 3.1%, 2.1% and 2.1% bit rate reduction at mode all-intra, random-access and low-delay B respectively in combination with better visual quality around edges and textures.