Incorrect PTL settings in multilayer bitstreams

[fbossen]

Following the inclusion of
​https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/-/merge_requests/2343

the VTM decoder fails to process the following bitstreams:

ILRPL_A_Huawei_2
OLS_A_Tencent_5
OLS_B_Tencent_5
OLS_C_Tencent_5
OPI_B_Nokia_3
SPATSCAL444_A_Qualcomm_2
SPATSCAL_A_Qualcomm_3
VPS_A_INTEL_3
VPS_B_ERICSSON_1
VPS_C_ERICSSON_2

It looks like these bitstreams may have incorrect PTL settings, in particular the value ptl_multilayer_enabled_flag may be incorrect.

[fbossen]

Trace of ILRPL_A_Huawei_2

[fbossen]

For example, in ILRPL_A_Huawei_2 (see attached trace file):

• the value of ptl_multilayer_enabled_flag is 1 for SPS 0, but 0 for OLS 0 in the VPS (OLS 0 contains only the layer that uses SPS 0). These values should be the same: "It is a requirement of bitstream conformance that, when NumLayersInOls[ i ] is equal to 1, the profile_tier_level( ) syntax structures signalled in the VPS and in the SPS for the i- th OLS shall be identical."

• the value of ptl_multilayer_enabled_flag is 0 for OLS 1 in the VPS, but OLS 1 contains two layers that are dependent. The value should thus be 1.

[siwamura]

These issues may be resolved after applying additional encoder fix related to JVET-AB0085.
The encoder fix is not yet submitted as a merge request but soon after the meeting it will be done.

[iole_moccagatta]

The 10 streams have been re-generated and are correctly decoded by VTM-20.2. They are been uploaded to /jvet-site/bitstream_exchange/VVC/under_test/VTM-20.2

I think we can close this ticket.