JVET-Q0277 AHG8/AHG9: Layer dependency constraints for parameter set reference [B. Choi, S. Wenger, S. Liu (Tencent)]
This contribution was discussed Saturday 11 January at 1955 in Track A (chaired by GJS).
In this contribution, it is proposed to impose additional constraints to make the support of parameter set reference across layers clear. The proposed constraint is that a coded slice NAL unit shall only refer to a PPS/APS in the same layer or in a (direct) reference layer, and a PPS NAL unit shall only refer to a SPS in the same layer or in a (direct) reference layer.
The proposal would disallow sharing across independent layers.
The current text could be misinterpreted as saying that there must be some VCL NAL unit that refers to the SPS/PPS/APS.
Decision: Only allow references to SPSs/PPSs/APSs that are in the current or lower layer that is in an OLS that includes the VCL NAL unit. Ye-Kui Wang is responsible for the providing text. B. Choi is to provide the conformance check for the decoder software.