Checking of JCCR flag in deblocking filter process

[LiZhang]

In BS setting process, i.e., sub-clause 8.8.3.5 on Derivation process of boundary filtering strength, the followings are checked in order:
– The variable bS[ xDi ][ yDj ] is derived as follows:

– If cIdx is equal to 0 and both samples p0 and q0 are in a coding block with intra_bdpcm_flag equal to 1, bS[ xDi ][ yDj ] is set equal to 0.
– Otherwise, if the sample p0 or q0 is in the coding block of a coding unit coded with intra prediction mode, bS[ xDi ][ yDj ] is set equal to 2.
– Otherwise, if the block edge is also a transform block edge and the sample p0 or q0 is in a coding block with ciip_flag equal to 1, bS[ xDi ][ yDj ] is set equal to 2.
– Otherwise, if the block edge is also a transform block edge and the sample p0 or q0 is in a transform block which contains one or more non-zero transform coefficient levels, bS[ xDi ][ yDj ] is set equal to 1.
– Otherwise, if the block edge is also a transform block edge, cIdx is greater than 0, and the sample p0 or q0 is in a transform unit with tu_joint_cbcr_residual_flag equal to 1, bS[ xDi ][ yDj ] is set equal to 1.

...

The conditional check of JCCR flag (bold text above) could be omitted, according to the following reasons:
1) JCCR could be applied to intra coded blocks: for this case, BS has already been set to 2.
2) JCCR could be applied to non-intra coded blocks only when both cbf_cb and cbf_cr are equal to 1. For this case, BS has already been set to 1 according to the check of 'sample p0 or q0 is in a transform block which contains one or more non-zero transform coefficient level'.

[bbross]

Thanks for reporting.

This will be fixed JVET-P2001-vC.