JVET-G0097 EE4: ERP/EAP-based segmented sphere projection with different padding sizes [Y.-H. Lee, H.-C. Lin, J.-L. Lin, S.-K. Chang, C.-C. Ju (MediaTek)]

From summary report G0010:

Brief description of the technology.

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. By applying the equal-area projection on the equatorial segment with padding on the poles, better quality consistency can be reached and virtual artefacts are efficiently reduced.

Questions recommended to be answered during EE tests:

To compare SSP with this proposal, investigate the following aspects in this EE:

• [Q] EAP vs ERP in the center section.

[A]: The difference in the performance between ERP and EAP based SSP is 0.3~0.4%.

• [Q] Padding widths for SSP-based projections. Including some informal subjective testing.

[A]: Padding improves performance ~1%, size = 8 seems to be enough.

Previous proposal JVET-F0037

Brief description of the technology.

This contribution describes a padding method for the SSP format in order to mitigate the seam artefact. In order to mitigate this artefact, padding pixels are added to border area.

The following aspects should be further studied in this EE:

Questions recommended to be answered during EE tests:

• [Q] Padding widths for SSP projection, but without changing the padding width per sequence.

[A]: Objectively padding leads to the lose 9.7% gain 8.2% gain, but there visual quality improvement is observed. Padding size 8 seams to be sufficient enough.