Semantics of same_qp_table_for_chroma for joint Cb-Cr

[bappadityaray]

When same_qp_table_for_chroma equal to 0, two tables are signalled (for Cb and Cr) for sps_joint_cbcr_enabled_flag is 0, instead of three (i.e., table for joint cb-cr is not present).

Proposed semantics:
same_qp_table_for_chroma equal to 1 specifies that only one chroma QP mapping table is signalled and this table applies to Cb and Cr residuals and additionally to joint Cb-Cr residuals when sps_joint_cbcr_enabled_flag equal to 1. same_qp_table_for_chroma equal to 0 specifies that chroma QP mapping tables for Cb and Cr, and additionally for joint Cb-Cr when sps_joint_cbcr_enabled_flag equal to 1 are signalled in the SPS. When same_qp_table_for_chroma is not present in the bitstream, the value of same_qp_table_for_chroma is inferred to be equal to 1.

[bappadityaray]

When same_qp_table_for_chroma equal to 0, two tables are signalled (for Cb and Cr) for sps_joint_cbcr_enabled_flag is 0, instead of three (i.e., table for joint cb-cr is not present).

Proposed semantics:
same_qp_table_for_chroma equal to 1 specifies that only one chroma QP mapping table is signalled and this table applies to Cb and Cr residuals, and additionally to joint Cb-Cr residuals when sps_joint_cbcr_enabled_flag is equal to 1. same_qp_table_for_chroma equal to 0 specifies that chroma QP mapping tables for Cb and Cr, and additionally for joint Cb-Cr when sps_joint_cbcr_enabled_flag is equal to 1, are signalled in the SPS. When same_qp_table_for_chroma is not present in the bitstream, the value of same_qp_table_for_chroma is inferred to be equal to 1.

[bbross]

Thanks for reporting.

This will be fixed JVET-P2001-vC.