Some inferred value from JVET-Q0420 are not integrated into JVET-Q2001-v9

[auyeung]

The inferred value of pps_slice_chroma_qp_offsets_present_flag and pps_cu_chroma_qp_offset_list_enabled_flag from JVET-Q0420 were not integrated into JVET-Q2001-v9. In JVET-Q2001-v9, when pps_chroma_tool_offsets_present_flag is 0, these flags are not present in the bitstream, and their inferred value are needed to decode the bitstream.

JVET-Q0420 proposed the followings:

pps_slice_chroma_qp_offsets_present_flag equal to 1 indicates that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice headers. pps_slice_chroma_qp_offsets_present_flag equal to 0 indicates that these syntax elements are not present in the associated slice headers. When ChromaArrayType is equal to 0, pps_slice_chroma_qp_offsets_present_flag shall be equal to 0. When pps_slice_chroma_qp_offsets_present_flag is not present, it is inferred to be equal to 0.

pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that the pic_cu_chroma_qp_offset_subdiv_intra_slice and pic_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and that cu_chroma_qp_offset_flag may be present in the transform unit syntax and the palette coding syntax. pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that the pic_cu_chroma_qp_offset_subdiv_intra_slice and pic_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are not present in picture headers referring to the PPS and that the cu_chroma_qp_offset_flag is not present in the transform unit syntax and the palette coding syntax. When ChromaArrayType is equal to 0, it is a requirement of bitstream conformance that the value of pps_cu_chroma_qp_offset_list_enabled_flag shall be equal to 0. When pps_cu_chroma_qp_offset_list_enabled_flag is not present, it is inferred to be equal to 0.

[yk]

You are right. The inference rules got lost when JVET-Q0420 was integrated into the draft text. We are sorry for that. Will be fixed in JVET-Q2001-vB.