Non-Separable Filtering with Side-Information and Contextually-Designed Filters for Next Generation Video Codecs

We propose two new in-loop filtering tools to augment the loop restoration process in AV1. Targeting challenging future compression scenarios that will be faced by the emerging AV2 standard, the proposed tools are designed to improve performance at both high and low bit-rates. Our non-separable Wiener filtering proposal aims to increase quality especially over directional features and textures in the decoded picture with the help of side-information at higher rates. The proposed pixel-adaptive filter complements at lower rates by improving performance without side-information relying solely on finely characterized pixel contexts. Simulation results show the rate-distortion efficacy of the proposed tools.