A direction-adaptive in-loop deartifacting filter for video coding

Recent video coding strategies, such as H.264/AVC, incorporate an in-loop deblocking filter in order to reduce the effects of quantization noise. These techniques are limited to treating blocky artifacts on smooth regions. In order to solve this, sparsity-based filtering techniques have been recently proposed for efficient filtering of edge and textured areas. More recently, direction-adaptive sparsity-based filtering has also allowed to exploit directional features on intra encoded pictures. This paper proposes a high-performance in-loop filter for deartifacting intra and inter encoded video data. This work extends for Inter frames the use of direction-adaptive sparsity-based filtering techniques and it improves performance by adaptively selecting filtering thresholds consistent with quantization noise statistics, local encoding conditions, compression requirements and the original signal. Thresholds are both spatially and temporally adapted to optimize video quality and/or coding cost. Selected thresholds are encoded and transmitted as side information to the decoder. Experimental results show significant bit rate savings and visual quality enhancement when compared to the state-of-the- art H.264/AVC codec using in-loop deblocking filtering.