JVET-Q0126 Initializations and propagation of Chroma QP Offset [K. Kawamura, S. Naito (KDDI)]
Chroma QP offset-scheme was introduced in the 15th JVET meeting, which was also used for the decision of chroma deblocking filter from the previous meeting. This offset is signalled in the TU level in the working draft 6.0, which means that the offset is not signalled in the non-coded block where CBF is false. In this cases, an actual chroma QP values for the deblocking filter decision is ambiguous. In this contribution, initialization processes of offset values for some block levels are introduced. The most frequently case of the initialization is the unit of chroma quantization group while the least one case is the unit of slice header. At the same time, the offset values for the non-coded unit are propagated from that of the previous coding unit.
Other related contributions: JVET-Q0267, JVET-Q0476, JVET-Q0570-
See further notes under JVET-Q0267.