Boosted Affine Motion Compensation For Geometric Partitioning Mode

Geometric partitioning mode (GPM) is an inter coding tool developed for versatile video coding (VVC), which is utilized to split a coding block into two sub-partitions geometrically. These two GPM sub-partitions are predicted separately using translational motion compensation and subsequently blended. Recently, GPM with affine prediction (GPM-affine) has been introduced in the enhanced compression model (ECM) to facilitate affine motion compensation for predicting the GPM sub-partitions. To further enhance the efficiency of GPM-affine, a method of boosted affine motion compensation for geometric partitioning mode (BAMC-GPM) is proposed in this paper. Specifically, the affine motion information in GPM-affine can be refined using a template-based approach, where a motion vector offset is derived based on template costs and utilized to update the control point motion vectors. Experimental results demonstrate that BAMC-GPM achieves average Bjontegaard Delta rate (BD-rate) savings of 0.04% and 0.12% compared to ECM-14.0 under random access (RA) and low delay B (LDB) configurations, respectively. It is noted that BAMC-GPM has been adopted into ECM during the 36th Joint Video Experts Team (JVET) meeting in 2024.