A study on flexible block partitioning for future video coding standards

For each generation of video coding standard, increasing the block partitioning flexibility has been very efficient. From fixed-size square blocks to rectangle-sized blocks, the new block shapes have significantly improved the video compression efficiency. During the development of Versatile Video Coding (VVC), the latest video standard developed by the Moving Picture Experts Group (MPEG), it was shown that the flexible partitioning, adding the Binary Tree (BT) and the Ternary Tree (TT) splits on top of the Quadtree (QT) splits, was the tool bringing the highest compression gains over previous standard High Efficiency Video Coding (HEVC). BT and TT splits brought a lot of flexibility to the block partitioning mechanism. During the VVC development, more flexible partitioning tools have also been studied, namely Asymmetric Binary Tree (ABT). In this paper, we show how increasing partition flexibility on top of newest video codec still brings additional gains.