We are currently adding range extensions support to Argon Streams. We are working from the head of the HM-range-extensions branch.

In TDecSbac::parseChromaQpAdjustment() (TDecSbac.cpp), cu_chroma_qp_adjustment_idc is read and set over the area of the current TU. This is incorrect, as it should be set over the area of the entire current chroma QP adjustment unit, analogous to what is done for delta QP.

To fix this, replace the following line:

  cu->setChromaQpAdjSubParts( symbol, absPartIdx, depth );

with:

  UInt uiAbsChromaQpAdjCUPartIdx = (absPartIdx>>((g_uiMaxCUDepth - cu->getSlice()->getPPS()->getMaxCuChromaQpAdjDepth())<<1))<<((g_uiMaxCUDepth - cu->getSlice()->getPPS()->getMaxCuChromaQpAdjDepth())<<1) ;
  UInt uiChromaQpAdjCUDepth =   min(depth,cu->getSlice()->getPPS()->getMaxCuChromaQpAdjDepth()) ;
  
  cu->setChromaQpAdjSubParts( symbol, uiAbsChromaQpAdjCUPartIdx, uiChromaQpAdjCUDepth );

This fixes this issue in the decoder - I guess a similar fix may be needed for the encoder.