JVET-F0052 AHG8: EAP-based segmented sphere projection with padding [Y.-H. Lee, J.-L. Lin, S.-K. Chang, C.-C. Ju (MediaTek)]
Discussion chaired by J. Boyce
This contribution proposes an EAP-based segmented sphere projection which uses equal-area projection (EAP) on the equatorial segment and applies padding on the north and south poles. The experimental results reportedly demonstrate that the proposed EAP-based segmented sphere projection achieves 11.33%, 11.21%, 11.28% and 11.35% BD-rate reduction in S-PSNR-NN, S-PSNR-I, CPP-PSNR, and WS-PSNR, respectively, as compared to ERP.
The padding width is 32 pixels. The face size is reduced to fit in same coded picture size. More coding gains than SSP were reported, with reduced subjective artefacts. It seemed difficult to separate the impact of the EAP center from the padding.
This has some similarity with JVET-F0026, which also had EAP in the center region.
It was agreed to start an EE on SSP projection modifications and padding, to compare SSP with this proposal.
Aspects to study in the EE:
- EAP vs ERP in the center section
- Padding widths for SSP-based projections. Including some informal subjective testing.