JVET-V0097 AHG12: Unsymmetric partitioning methods in video coding [K. Zhang, L. Zhang, Z. Deng, N. Zhang, Y. Wang (Bytedance)]
This contribution presents two unsymmetric partitioning methods denoted as unsymmetric binary-tree (UBT) partitioning and unsymmetric quad-tree (UQT) partitioning. UBT and UQT can be applied for blocks with dimensions no greater than 64×64. On top of the EE code of JVET-U0100, simulation results of the proposed method are reported as below:
Tool-on test (VTM-11 as the anchor):
- AI: -0.68%, 190%, 104%; RA: -1.48%, 204%, 102%; LB: -1.46%, 206%, 108%.
Tool-off test (EE code as the anchor):
- AI: -0.61%, 187%, 103%; RA: -1.23%, 201%, 101%; LB: x%, x%, x%.
The ¼ vs. ¾ split (UBT) requires four new transforms: 6, 12, 24, 48 to be introduced
Also has a ternary split (UQT) 1/8 3/4 1/8.
The ¾ part must be further split into 1/3 2/3, therefore no additional transform.
Similar to JVET-V0083 (UBT is equivalent to ABT), but gain is lower.
It was suggested to study lower-complex encoder configurations.
It was agreed to study this in an EE.