Mismatch between SW and spec on DepQuant state transition

[wzeng]

In VVC D7 vB, par_level_flag[n] is used for DepQuant state transition.

QState = QStateTransTable[ QState ][ par_level_flag[ n ] ]

But in VTM7.0rc1, (level & 1) is used (in function Quantizer::dequantBlock).

state = ( 32040 >> ((state<<2)+((level&1)<<1)) ) & 3;

When level=1, par_level_flag[n] is not parsed and it's inferred to be 0. In this case, (level & 1) != par_level_flag[n].

Suggest to align the text with VTM by changing the line to:

QState = QStateTransTable[ QState ][ AbsLevel[xC][yC] & 1]

[schwarz]

I agree.

There are three places in the syntax, where the state transition table is used. Two of them are correct (they use AbsLevel1 or Abslevel), but the last one (in final reconstruction), should be changed from

QState = QStateTransTable[ QState ][ par_level_flag[ n ] ]

to

QState = QStateTransTable[ QState ][ AbsLevel[ xC ][ yC ] & 1 ]

[bbross]

Thanks for reporting.

This will be fixed JVET-P2001-vC.