JVET-AL0289 AHG4: potential updates for VVC multi-layer verification test plan [P. de Lagrange (InterDigital)] [late]

This document proposes updates to the verification test plan for VVC multilayer coding.For spatial scalability, it is suggested to

• Test only 2x scaling factor, HD+UHD
• Select only one QP for base layer, targeting around MOS 7 or 8 when upscaled to UHD, mostly due to loss of detail sharpness. Suitable QP may be around 27 to 29.
• Use 10% bitrate for the enhancement layer (select enhancement layer QP that gives the closest bitrate ratio)
• Test against both upscaled base layer and single-layer UHD
• Optionally, also test SHVC in the same configuration (using the SHM version and configuration used in SHVC verification tests). However, testing against SHVC is more relevant in category 2 and could be dropped for category 1.

For quality ladder, it is suggested to focus on:

• 2x scaling ratio using HD+UHD, with 50% bitrate for the enhancement layer (equal bitrate for both layers, like in SHVC verification tests)
• 1.5x scaling ratio using 720p+HD, with 33% bitrate for the enhancement layer (half bitrate for enhancement layer compared to base layer, like in SHVC verification tests)
• Test against full-resolution single-layer
• Use 3 or 4 rate points for each sequence, potentially dropping the low quality end (e.g. focus on MOS 4, 6, 8)
• Also test SHVC in similar conditions (using SHM version and configurations used in SHVC verification tests)

Test sequences are suggested to be used (possibly a selection) from the set described in AG 5 N 160.

It may be necessary to conduct preparation work in the AHG period before the 39^th meeting, to settle on test sequences, VTM version, precise configuration, and organize encoding of bitstreams.

For SHVC, an HEVC base layer would be used, even though in principle VVC would be possible as external reference.

Further work in AHG4, target to propose a draft of updated test plan as input to the 39^th meeting, and potentially conduct expert viewing in Daejeon.

AHG4: Test and training material (0)

This section is kept as a template for future use.

Proposals on new test materials are also included in 4.16 and 5.1.4.

AHG5: Conformance test development (0)

This section is kept as a template for future use.

AHG7: ECM tool assessment (5+2)

Contributions in this area were discussed during 1555–1735 on Friday 28 March 2025 (chaired by JRO).