Unsymmetrical Quad-tree Partitioning for Audio Video coding Standard-3 (AVS-3)

Audio and Video coding Standard-3 (AVS-3) is an emerging next-generation video coding standard beyond AVS-2. The Quad-Tree/Binary-Tree (QTBT) plus Extend Quad-Tree (EQT) partitioning structure has been adopted in AVS3. In this paper, Unsymmetrical Quad-Tree (UQT) partitioning is proposed to explore the potential coding efficiency of partitioning further. Particularly, UQT partitioning splits a parent block into four sub-blocks asymmetrically with 1:4:2:1 or 1:2:4:1 ratio. Not only UQT partitioning can complement the current QTBT plus EQT partition structure but also can characterize the pattern of multifarious video content more effectively. Experiments are conducted on the HPM3.2 platform and the simulation results demonstrate that the proposed UQT partitioning can achieve 0.66%, 0.77% and 0.75% BD-bitrate savings for Y, Cb and Cr components on average under the random-access configuration, respectively.