JVET-AM0079 AHG9: On the SPO SEI message [Y. He, L. Kerofsky, S. Zhao, M. Karczewicz (Qualcomm)]

Item 3 discussed further on 28 June 2025. See notes under JVET-AM0321.

This contribution proposes the following changes to the SPO SEI message.

• Add “critical process” in VSEI Table 24 and replace “root processes” with “critical processes” in the TuC accordingly to maintain consistency.
• Add a flag to enable inference of the complexity of the critical processes complexity from that of the processing chain when applicable.
• Modify the constraint of the syntax element po_sei_prefix_flag to avoid potential ambiguity.

Suggest to editors to use the “critical process” naming.

It was noted that the flag may not be needed because it is known by the decoder whether or not the NNPF is in the critical process.

An encoder may avoid double signalling of the complexity parameters with the po_critical_complexity_info_present_flag.

No action on this aspect.

For the 3^rd aspect, see the notes in JVET-AM0321.

JVET-AM0079 AHG9: On the SPO SEI message