N0280 – Transform Skip Residual Coding

[bheng]

1.) The following context derivation for the TS significant coefficient group flag seems to be off by 1.

unsigned sigLeft = unsigned( int( CGPosX - 1 ) > 0 ? ...
unsigned sigAbove = unsigned( int( CGPosY - 1 ) > 0 ? ...

Specifically, ( CGPosX - 1 ) > 0 and ( CGPosY - 1 ) > 0. Shouldn’t these just be CGPos > 0? As it is now, this code ignores the first row/column of context.

2.) The following quantization selection logic (dependent quant vs. regular quant) for mtsIdx ==1 should only apply to luma, not chroma.

if( tu.cs->slice->getDepQuantEnabledFlag() && tu.mtsIdx != 1 )