IntraSearch.cpp

    {
      // exit condition if the accumulated cost is already larger than the best cost so far (no impact in RD performance)
      if (cs.cost > bestCostSoFar)
      {
        earlySkipISP = true;
        break;
      }
      else if (subTuCounter < nSubPartitions)
      {
        // more restrictive exit condition
        double threshold = nSubPartitions == 2 ? 0.95 : subTuCounter == 1 ? 0.83 : 0.91;
        if (subTuCounter < nSubPartitions && cs.cost > bestCostSoFar * threshold)
        {
          earlySkipISP = true;
          break;
        }
      }
    }
  } while (partitioner.nextPart(cs));   // subpartitions loop

  partitioner.exitCurrSplit();
  const UnitArea& currArea = partitioner.currArea();
  const uint32_t  currDepth = partitioner.currTrDepth;

  if (earlySkipISP)
  {
    cs.cost = MAX_DOUBLE;
  }
  else
  {
    cs.cost = m_pcRdCost->calcRdCost(cs.fracBits, cs.dist);
    // The cost check is necessary here again to avoid superfluous operations if the maximum number of coded subpartitions was reached and yet ISP did not win
    if (cs.cost < bestCostSoFar)
    {
      cs.setDecomp(cu.Y());
      cs.picture->getRecoBuf(currArea.Y()).copyFrom(cs.getRecoBuf(currArea.Y()));

      for (auto& ptu : cs.tus)
      {
        if (currArea.Y().contains(ptu->Y()))
        {
          TU::setCbfAtDepth(*ptu, COMPONENT_Y, currDepth, splitCbfLuma ? 1 : 0);
        }
      }
    }
    else
    {
      earlySkipISP = true;
    }
  }
  return !earlySkipISP;
}


bool IntraSearch::xRecurIntraCodingLumaQT( CodingStructure &cs, Partitioner &partitioner, const double bestCostSoFar, const int subTuIdx, const PartSplit ispType, const bool ispIsCurrentWinner, bool mtsCheckRangeFlag, int mtsFirstCheckId, int mtsLastCheckId, bool moreProbMTSIdxFirst )
{
        int   subTuCounter = subTuIdx;
  const UnitArea &currArea = partitioner.currArea();
  const CodingUnit     &cu = *cs.getCU( currArea.lumaPos(), partitioner.chType );
        bool  earlySkipISP = false;
  uint32_t currDepth       = partitioner.currTrDepth;
  const SPS &sps           = *cs.sps;
  const PPS &pps           = *cs.pps;
  const bool keepResi      = pps.getPpsRangeExtension().getCrossComponentPredictionEnabledFlag() || KEEP_PRED_AND_RESI_SIGNALS;
  bool bCheckFull          = true;
  bool bCheckSplit         = false;
  bCheckFull               = !partitioner.canSplit( TU_MAX_TR_SPLIT, cs );
  bCheckSplit              = partitioner.canSplit( TU_MAX_TR_SPLIT, cs );

  if( cu.ispMode )
  {
    bCheckSplit = partitioner.canSplit( ispType, cs );
    bCheckFull = !bCheckSplit;
  }
  uint32_t    numSig           = 0;

  double     dSingleCost                        = MAX_DOUBLE;
  Distortion uiSingleDistLuma                   = 0;
  uint64_t   singleFracBits                     = 0;
  bool       checkTransformSkip                 = sps.getTransformSkipEnabledFlag();
  int        bestModeId[ MAX_NUM_COMPONENT ]    = { 0, 0, 0 };
  uint8_t    nNumTransformCands                 = cu.mtsFlag ? 4 : 1;
  uint8_t    numTransformIndexCands             = nNumTransformCands;

  const TempCtx ctxStart  ( m_CtxCache, m_CABACEstimator->getCtx() );
  TempCtx       ctxBest   ( m_CtxCache );

  CodingStructure *csSplit = nullptr;
  CodingStructure *csFull  = nullptr;

  CUCtx cuCtx;
  cuCtx.isDQPCoded = true;
  cuCtx.isChromaQpAdjCoded = true;

  if( bCheckSplit )
  {
    csSplit = &cs;
  }
  else if( bCheckFull )
  {
    csFull = &cs;
  }

  bool validReturnFull = false;

  if( bCheckFull )
  {
    csFull->cost = 0.0;

    TransformUnit &tu = csFull->addTU( CS::getArea( *csFull, currArea, partitioner.chType ), partitioner.chType );
    tu.depth = currDepth;

    const bool tsAllowed  = TU::isTSAllowed( tu, COMPONENT_Y );
    const bool mtsAllowed = CU::isMTSAllowed( cu, COMPONENT_Y );
    std::vector<TrMode> trModes;

    if( sps.getUseLFNST() )
    {
      checkTransformSkip &= tsAllowed;
      checkTransformSkip &= !cu.mtsFlag;
      checkTransformSkip &= !cu.lfnstIdx;

      if( !cu.mtsFlag && checkTransformSkip )
      {
        trModes.push_back( TrMode( 0, true ) ); //DCT2
        trModes.push_back( TrMode( 1, true ) ); //TS
      }
    }
    else
    {
      nNumTransformCands = 1 + ( tsAllowed ? 1 : 0 ) + ( mtsAllowed ? 4 : 0 ); // DCT + TS + 4 MTS = 6 tests

#if JVET_Q0820_ACT 
      if (m_pcEncCfg->getCostMode() == COST_LOSSLESS_CODING)
      {
        nNumTransformCands = 1;
        CHECK(!tsAllowed && !cu.bdpcmMode, "transform skip should be enabled for LS");
        if (cu.bdpcmMode)
        {
          trModes.push_back(TrMode(0, true));
        }
        else
        {
          trModes.push_back(TrMode(1, true));
        }
      }
      else
      {
#endif
      trModes.push_back( TrMode( 0, true ) ); //DCT2
      if( tsAllowed )
      {
        trModes.push_back( TrMode( 1, true ) );
      }
      if( mtsAllowed )
      {
        for( int i = 2; i < 6; i++ )
        {
          trModes.push_back( TrMode( i, true ) );
        }
      }
#if JVET_Q0820_ACT 
      }
#endif 
    }

    CHECK( !tu.Y().valid(), "Invalid TU" );

    CodingStructure &saveCS = *m_pSaveCS[0];

    TransformUnit *tmpTU = nullptr;

    Distortion singleDistTmpLuma = 0;
    uint64_t     singleTmpFracBits = 0;
    double     singleCostTmp     = 0;
    int        firstCheckId      = ( sps.getUseLFNST() && mtsCheckRangeFlag && cu.mtsFlag ) ? mtsFirstCheckId : 0;

    //we add the MTS candidates to the loop. TransformSkip will still be the last one to be checked (when modeId == lastCheckId) as long as checkTransformSkip is true
    int        lastCheckId       = sps.getUseLFNST() ? ( ( mtsCheckRangeFlag && cu.mtsFlag ) ? ( mtsLastCheckId + ( int ) checkTransformSkip ) : ( numTransformIndexCands - ( firstCheckId + 1 ) + ( int ) checkTransformSkip ) ) :
                                   trModes[ nNumTransformCands - 1 ].first;
    bool isNotOnlyOneMode        = sps.getUseLFNST() ? lastCheckId != firstCheckId : nNumTransformCands != 1;

    if( isNotOnlyOneMode )
    {
      saveCS.pcv     = cs.pcv;
      saveCS.picture = cs.picture;
      saveCS.area.repositionTo(cs.area);
      saveCS.clearTUs();
      tmpTU = &saveCS.addTU(currArea, partitioner.chType);
    }

    bool    cbfBestMode      = false;
    bool    cbfBestModeValid = false;
    bool    cbfDCT2  = true;

    double bestDCT2cost = MAX_DOUBLE;
    double threshold = m_pcEncCfg->getUseFastISP() && !cu.ispMode && ispIsCurrentWinner && nNumTransformCands > 1 ? 1 + 1.4 / sqrt( cu.lwidth() * cu.lheight() ) : 1;
    for( int modeId = firstCheckId; modeId <= ( sps.getUseLFNST() ? lastCheckId : ( nNumTransformCands - 1 ) ); modeId++ )
    {
      uint8_t transformIndex = modeId;

      if( sps.getUseLFNST() )
      {
        if( ( transformIndex < lastCheckId ) || ( ( transformIndex == lastCheckId ) && !checkTransformSkip ) ) //we avoid this if the mode is transformSkip
        {
          // Skip checking other transform candidates if zero CBF is encountered and it is the best transform so far
          if( m_pcEncCfg->getUseFastLFNST() && transformIndex && !cbfBestMode && cbfBestModeValid )
          {
            continue;
          }
        }
      }
      else
      {
#if JVET_AHG14_LOSSLESS
        if( !( m_pcEncCfg->getCostMode() == COST_LOSSLESS_CODING ) )
        {
#endif
        if( !cbfDCT2 || ( m_pcEncCfg->getUseTransformSkipFast() && bestModeId[ COMPONENT_Y ] == MTS_SKIP))
        {
          break;
        }
        if( !trModes[ modeId ].second )
        {
          continue;
        }
        //we compare the DCT-II cost against the best ISP cost so far (except for TS)
        if (m_pcEncCfg->getUseFastISP() && !cu.ispMode && ispIsCurrentWinner && trModes[modeId].first != MTS_DCT2_DCT2 && (trModes[modeId].first != MTS_SKIP || !tsAllowed) && bestDCT2cost > bestCostSoFar * threshold)
        {
          continue;
        }
#if JVET_AHG14_LOSSLESS
        }
#endif
        tu.mtsIdx[COMPONENT_Y] = trModes[modeId].first;
      }


      if ((modeId != firstCheckId) && isNotOnlyOneMode)
      {
        m_CABACEstimator->getCtx() = ctxStart;
      }

      int default0Save1Load2 = 0;
      singleDistTmpLuma = 0;

      if( modeId == firstCheckId && ( sps.getUseLFNST() ? ( modeId != lastCheckId ) : ( nNumTransformCands > 1 ) ) )
      {
        default0Save1Load2 = 1;
      }
      else if (modeId != firstCheckId)
      {
        if( sps.getUseLFNST() && !cbfBestModeValid )
        {
          default0Save1Load2 = 1;
        }
        else
        {
          default0Save1Load2 = 2;
        }
      }
      if( cu.ispMode )
      {
        default0Save1Load2 = 0;
      }
      if( sps.getUseLFNST() )
      {
        if( cu.mtsFlag )
        {
          if( moreProbMTSIdxFirst )
          {
            const ChannelType     chType      = toChannelType( COMPONENT_Y );
            const CompArea&       area        = tu.blocks[ COMPONENT_Y ];
            const PredictionUnit& pu          = *cs.getPU( area.pos(), chType );
            uint32_t              uiIntraMode = pu.intraDir[ chType ];

            if( transformIndex == 1 )
            {
              tu.mtsIdx[COMPONENT_Y] = (uiIntraMode < 34) ? MTS_DST7_DCT8 : MTS_DCT8_DST7;
            }
            else if( transformIndex == 2 )
            {
              tu.mtsIdx[COMPONENT_Y] = (uiIntraMode < 34) ? MTS_DCT8_DST7 : MTS_DST7_DCT8;
            }
            else
            {
              tu.mtsIdx[COMPONENT_Y] = MTS_DST7_DST7 + transformIndex;
            }
          }
          else
          {
            tu.mtsIdx[COMPONENT_Y] = MTS_DST7_DST7 + transformIndex;
          }
        }
        else
        {
          tu.mtsIdx[COMPONENT_Y] = transformIndex;
        }

        if( !cu.mtsFlag && checkTransformSkip )
        {
          xIntraCodingTUBlock( tu, COMPONENT_Y, false, singleDistTmpLuma, default0Save1Load2, &numSig, modeId == 0 ? &trModes : nullptr, true );
          if( modeId == 0 )
          {
            for( int i = 0; i < 2; i++ )
            {
              if( trModes[ i ].second )
              {
                lastCheckId = trModes[ i ].first;
              }
            }
          }
        }
        else
        {
          xIntraCodingTUBlock( tu, COMPONENT_Y, false, singleDistTmpLuma, default0Save1Load2, &numSig );
        }
      }
      else
      {
        if( nNumTransformCands > 1 )
        {
          xIntraCodingTUBlock( tu, COMPONENT_Y, false, singleDistTmpLuma, default0Save1Load2, &numSig, modeId == 0 ? &trModes : nullptr, true );
          if( modeId == 0 )
          {
            for( int i = 0; i < nNumTransformCands; i++ )
            {
              if( trModes[ i ].second )
              {
                lastCheckId = trModes[ i ].first;
              }
            }
          }
        }
        else
        {
          xIntraCodingTUBlock( tu, COMPONENT_Y, false, singleDistTmpLuma, default0Save1Load2, &numSig );
        }
      }

#if JVET_Q0516_MTS_SIGNALLING_DC_ONLY_COND 
      cuCtx.mtsLastScanPos = false;
#endif
      //----- determine rate and r-d cost -----
      if( ( sps.getUseLFNST() ? ( modeId == lastCheckId && modeId != 0 && checkTransformSkip ) : ( trModes[ modeId ].first != 0 ) ) && !TU::getCbfAtDepth( tu, COMPONENT_Y, currDepth ) )
      {
        //In order not to code TS flag when cbf is zero, the case for TS with cbf being zero is forbidden.
#if JVET_Q0820_ACT 
        if (m_pcEncCfg->getCostMode() != COST_LOSSLESS_CODING)
#endif 
        singleCostTmp = MAX_DOUBLE;
#if JVET_Q0820_ACT 
        else
        {
          singleTmpFracBits = xGetIntraFracBitsQT(*csFull, partitioner, true, false, subTuCounter, ispType, &cuCtx);
          singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma);
        }
#endif 
      }
      else
      {
        if( cu.ispMode && m_pcRdCost->calcRdCost( csFull->fracBits, csFull->dist + singleDistTmpLuma ) > bestCostSoFar )
        {
          earlySkipISP = true;
        }
        else
        {
          singleTmpFracBits = xGetIntraFracBitsQT( *csFull, partitioner, true, false, subTuCounter, ispType, &cuCtx );
        }
#if JVET_Q0516_MTS_SIGNALLING_DC_ONLY_COND  
        if (tu.mtsIdx[COMPONENT_Y] > MTS_SKIP)
        {
          if (!cuCtx.mtsLastScanPos)
          {
            singleCostTmp = MAX_DOUBLE;
          }
          else
          {
            singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma);
          }
        }
        else
#endif
        singleCostTmp     = m_pcRdCost->calcRdCost( singleTmpFracBits, singleDistTmpLuma );
      }

      if ( !cu.ispMode && nNumTransformCands > 1 && modeId == firstCheckId )
      {
        bestDCT2cost = singleCostTmp;
      }

      if (singleCostTmp < dSingleCost)
      {
        dSingleCost       = singleCostTmp;
        uiSingleDistLuma  = singleDistTmpLuma;
        singleFracBits    = singleTmpFracBits;

        if( sps.getUseLFNST() )
        {
          bestModeId[ COMPONENT_Y ] = modeId;
          cbfBestMode = TU::getCbfAtDepth( tu, COMPONENT_Y, currDepth );
          cbfBestModeValid = true;
          validReturnFull = true;
        }
        else
        {
          bestModeId[ COMPONENT_Y ] = trModes[ modeId ].first;
          if( trModes[ modeId ].first == 0 )
          {
            cbfDCT2 = TU::getCbfAtDepth( tu, COMPONENT_Y, currDepth );
          }
        }

        if( bestModeId[COMPONENT_Y] != lastCheckId )
        {
          saveCS.getPredBuf( tu.Y() ).copyFrom( csFull->getPredBuf( tu.Y() ) );
          saveCS.getRecoBuf( tu.Y() ).copyFrom( csFull->getRecoBuf( tu.Y() ) );

          if( keepResi )
          {
            saveCS.getResiBuf   ( tu.Y() ).copyFrom( csFull->getResiBuf   ( tu.Y() ) );
            saveCS.getOrgResiBuf( tu.Y() ).copyFrom( csFull->getOrgResiBuf( tu.Y() ) );
          }

          tmpTU->copyComponentFrom( tu, COMPONENT_Y );

          ctxBest = m_CABACEstimator->getCtx();
        }
      }
    }

    if( sps.getUseLFNST() && !validReturnFull )
    {
      csFull->cost = MAX_DOUBLE;

      if( bCheckSplit )
      {
        ctxBest = m_CABACEstimator->getCtx();
      }
    }
    else
    {
      if( bestModeId[COMPONENT_Y] != lastCheckId )
      {
        csFull->getPredBuf( tu.Y() ).copyFrom( saveCS.getPredBuf( tu.Y() ) );
        csFull->getRecoBuf( tu.Y() ).copyFrom( saveCS.getRecoBuf( tu.Y() ) );

        if( keepResi )
        {
          csFull->getResiBuf   ( tu.Y() ).copyFrom( saveCS.getResiBuf   ( tu.Y() ) );
          csFull->getOrgResiBuf( tu.Y() ).copyFrom( saveCS.getOrgResiBuf( tu.Y() ) );
        }

        tu.copyComponentFrom( *tmpTU, COMPONENT_Y );

        if( !bCheckSplit )
        {
          m_CABACEstimator->getCtx() = ctxBest;
        }
      }
      else if( bCheckSplit )
      {
        ctxBest = m_CABACEstimator->getCtx();
      }

      csFull->cost     += dSingleCost;
      csFull->dist     += uiSingleDistLuma;
      csFull->fracBits += singleFracBits;
    }
  }

  bool validReturnSplit = false;
  if( bCheckSplit )
  {
    //----- store full entropy coding status, load original entropy coding status -----
    if( bCheckFull )
    {
      m_CABACEstimator->getCtx() = ctxStart;
    }
    //----- code splitted block -----
    csSplit->cost = 0;

    bool uiSplitCbfLuma  = false;
    bool splitIsSelected = true;
    if( partitioner.canSplit( TU_MAX_TR_SPLIT, cs ) )
    {
      partitioner.splitCurrArea( TU_MAX_TR_SPLIT, cs );
    }

    if( cu.ispMode )
    {
      partitioner.splitCurrArea( ispType, *csSplit );
    }
    do
    {
      bool tmpValidReturnSplit = xRecurIntraCodingLumaQT( *csSplit, partitioner, bestCostSoFar, subTuCounter, ispType, false, mtsCheckRangeFlag, mtsFirstCheckId, mtsLastCheckId );
      subTuCounter += subTuCounter != -1 ? 1 : 0;
      if( sps.getUseLFNST() && !tmpValidReturnSplit )
      {
        splitIsSelected = false;
        break;
      }

      if( !cu.ispMode )
      {
        csSplit->setDecomp( partitioner.currArea().Y() );
      }
      else if( CU::isISPFirst( cu, partitioner.currArea().Y(), COMPONENT_Y ) )
      {
        csSplit->setDecomp( cu.Y() );
      }

      uiSplitCbfLuma |= TU::getCbfAtDepth( *csSplit->getTU( partitioner.currArea().lumaPos(), partitioner.chType, subTuCounter - 1 ), COMPONENT_Y, partitioner.currTrDepth );
      if( cu.ispMode )
      {
        //exit condition if the accumulated cost is already larger than the best cost so far (no impact in RD performance)
        if( csSplit->cost > bestCostSoFar )
        {
          earlySkipISP    = true;
          splitIsSelected = false;
          break;
        }
        else
        {
          //more restrictive exit condition
          bool tuIsDividedInRows = CU::divideTuInRows( cu );
          int nSubPartitions = tuIsDividedInRows ? cu.lheight() >> floorLog2(cu.firstTU->lheight()) : cu.lwidth() >> floorLog2(cu.firstTU->lwidth());
          double threshold = nSubPartitions == 2 ? 0.95 : subTuCounter == 1 ? 0.83 : 0.91;
          if( subTuCounter < nSubPartitions && csSplit->cost > bestCostSoFar*threshold )
          {
            earlySkipISP    = true;
            splitIsSelected = false;
            break;
          }
        }
      }



    } while( partitioner.nextPart( *csSplit ) );

    partitioner.exitCurrSplit();

    if( splitIsSelected )
    {
      for( auto &ptu : csSplit->tus )
      {
        if( currArea.Y().contains( ptu->Y() ) )
        {
          TU::setCbfAtDepth( *ptu, COMPONENT_Y, currDepth, uiSplitCbfLuma ? 1 : 0 );
        }
      }

      //----- restore context states -----
      m_CABACEstimator->getCtx() = ctxStart;

      cuCtx.violatesLfnstConstrained[CHANNEL_TYPE_LUMA] = false;
      cuCtx.violatesLfnstConstrained[CHANNEL_TYPE_CHROMA] = false;
      cuCtx.lfnstLastScanPos = false;
      cuCtx.violatesMtsCoeffConstraint = false;
#if JVET_Q0516_MTS_SIGNALLING_DC_ONLY_COND 
      cuCtx.mtsLastScanPos = false;
#endif

      //----- determine rate and r-d cost -----
      csSplit->fracBits = xGetIntraFracBitsQT( *csSplit, partitioner, true, false, cu.ispMode ? 0 : -1, ispType, &cuCtx );

      //--- update cost ---
      csSplit->cost     = m_pcRdCost->calcRdCost(csSplit->fracBits, csSplit->dist);

      validReturnSplit = true;
    }
  }

  bool retVal = false;
  if( csFull || csSplit )
  {
    if( !sps.getUseLFNST() || validReturnFull || validReturnSplit )
    {
      {
        // otherwise this would've happened in useSubStructure
        cs.picture->getRecoBuf( currArea.Y() ).copyFrom( cs.getRecoBuf( currArea.Y() ) );
        cs.picture->getPredBuf( currArea.Y() ).copyFrom( cs.getPredBuf( currArea.Y() ) );
      }

      if( cu.ispMode && earlySkipISP )
      {
        cs.cost = MAX_DOUBLE;
      }
      else
      {
        cs.cost = m_pcRdCost->calcRdCost( cs.fracBits, cs.dist );
        retVal = true;
      }
    }
  }
  return retVal;
}

bool IntraSearch::xRecurIntraCodingACTQT(CodingStructure &cs, Partitioner &partitioner, bool mtsCheckRangeFlag, int mtsFirstCheckId, int mtsLastCheckId, bool moreProbMTSIdxFirst)
{
  const UnitArea &currArea = partitioner.currArea();
  uint32_t       currDepth = partitioner.currTrDepth;
  const Slice    &slice = *cs.slice;
  const SPS      &sps = *cs.sps;

  bool bCheckFull = !partitioner.canSplit(TU_MAX_TR_SPLIT, cs);
  bool bCheckSplit = !bCheckFull;

  TempCtx ctxStart(m_CtxCache, m_CABACEstimator->getCtx());
  TempCtx ctxBest(m_CtxCache);

  CodingStructure *csSplit = nullptr;
  CodingStructure *csFull = nullptr;
  if (bCheckSplit)
  {
    csSplit = &cs;
  }
  else if (bCheckFull)
  {
    csFull = &cs;
  }

  bool validReturnFull = false;

  if (bCheckFull)
  {
    TransformUnit        &tu = csFull->addTU(CS::getArea(*csFull, currArea, partitioner.chType), partitioner.chType);
    tu.depth = currDepth;
    const CodingUnit     &cu = *csFull->getCU(tu.Y().pos(), CHANNEL_TYPE_LUMA);
    const PredictionUnit &pu = *csFull->getPU(tu.Y().pos(), CHANNEL_TYPE_LUMA);
    CHECK(!tu.Y().valid() || !tu.Cb().valid() || !tu.Cr().valid(), "Invalid TU");
    CHECK(tu.cu != &cu, "wrong CU fetch");
    CHECK(cu.ispMode, "adaptive color transform cannot be applied to ISP");
    CHECK(pu.intraDir[CHANNEL_TYPE_CHROMA] != DM_CHROMA_IDX, "chroma should use DM mode for adaptive color transform");

    // 1. intra prediction and forward color transform

    PelUnitBuf orgBuf = csFull->getOrgBuf(tu);
    PelUnitBuf predBuf = csFull->getPredBuf(tu);
    PelUnitBuf resiBuf = csFull->getResiBuf(tu);
    PelUnitBuf orgResiBuf = csFull->getOrgResiBuf(tu);

    for (int i = 0; i < getNumberValidComponents(tu.chromaFormat); i++)
    {
      ComponentID          compID = (ComponentID)i;
      const CompArea       &area = tu.blocks[compID];
      const ChannelType    chType = toChannelType(compID);

      PelBuf         piOrg = orgBuf.bufs[compID];
      PelBuf         piPred = predBuf.bufs[compID];
      PelBuf         piResi = resiBuf.bufs[compID];

      initIntraPatternChType(*tu.cu, area);
      if (PU::isMIP(pu, chType))
      {
        initIntraMip(pu, area);
        predIntraMip(compID, piPred, pu);
      }
      else
      {
        predIntraAng(compID, piPred, pu);
      }

      piResi.copyFrom(piOrg);
      if (slice.getPicHeader()->getLmcsEnabledFlag() && m_pcReshape->getCTUFlag() && compID == COMPONENT_Y)
      {
        CompArea tmpArea(COMPONENT_Y, area.chromaFormat, Position(0, 0), area.size());
        PelBuf   tmpPred = m_tmpStorageLCU.getBuf(tmpArea);
        tmpPred.copyFrom(piPred);
        piResi.rspSignal(m_pcReshape->getFwdLUT());
        piResi.subtract(tmpPred);
      }
      else
        piResi.subtract(piPred);
    }

#if JVET_Q0820_ACT
    resiBuf.colorSpaceConvert(orgResiBuf, true, cs.slice->clpRng(COMPONENT_Y));
#else
    resiBuf.colorSpaceConvert(orgResiBuf, true);
#endif

    // 2. luma residual optimization 
    double     dSingleCostLuma = MAX_DOUBLE;
    bool       checkTransformSkip = sps.getTransformSkipEnabledFlag();
    int        bestLumaModeId = 0;
    uint8_t    nNumTransformCands = cu.mtsFlag ? 4 : 1;
    uint8_t    numTransformIndexCands = nNumTransformCands;

    const bool tsAllowed = TU::isTSAllowed(tu, COMPONENT_Y);
    const bool mtsAllowed = CU::isMTSAllowed(cu, COMPONENT_Y);
    std::vector<TrMode> trModes;

    if (sps.getUseLFNST())
    {
      checkTransformSkip &= tsAllowed;
      checkTransformSkip &= !cu.mtsFlag;
      checkTransformSkip &= !cu.lfnstIdx;

      if (!cu.mtsFlag && checkTransformSkip)
      {
        trModes.push_back(TrMode(0, true)); //DCT2
        trModes.push_back(TrMode(1, true)); //TS
      }
    }
    else
    {
#if JVET_Q0820_ACT 
      if (m_pcEncCfg->getCostMode() == COST_LOSSLESS_CODING)
      {
        nNumTransformCands = 1;
        CHECK(!tsAllowed && !cu.bdpcmMode, "transform skip should be enabled for LS");
        if (cu.bdpcmMode)
        {
          trModes.push_back(TrMode(0, true));
        }
        else
        {
          trModes.push_back(TrMode(1, true));
        }
      }
      else
      {
#endif 
      nNumTransformCands = 1 + (tsAllowed ? 1 : 0) + (mtsAllowed ? 4 : 0); // DCT + TS + 4 MTS = 6 tests

      trModes.push_back(TrMode(0, true)); //DCT2
      if (tsAllowed)
      {
        trModes.push_back(TrMode(1, true));
      }
      if (mtsAllowed)
      {
        for (int i = 2; i < 6; i++)
        {
          trModes.push_back(TrMode(i, true));
        }
      }
#if JVET_Q0820_ACT 
      }
#endif
    }

    CodingStructure &saveLumaCS = *m_pSaveCS[0];
    TransformUnit   *tmpTU = nullptr;
    Distortion      singleDistTmpLuma = 0;
    uint64_t        singleTmpFracBits = 0;
    double          singleCostTmp = 0;
    int             firstCheckId = (sps.getUseLFNST() && mtsCheckRangeFlag && cu.mtsFlag) ? mtsFirstCheckId : 0;
    int             lastCheckId = sps.getUseLFNST() ? ((mtsCheckRangeFlag && cu.mtsFlag) ? (mtsLastCheckId + (int)checkTransformSkip) : (numTransformIndexCands - (firstCheckId + 1) + (int)checkTransformSkip)) : trModes[nNumTransformCands - 1].first;
    bool            isNotOnlyOneMode = sps.getUseLFNST() ? lastCheckId != firstCheckId : nNumTransformCands != 1;

    if (isNotOnlyOneMode)
    {
      saveLumaCS.pcv = csFull->pcv;
      saveLumaCS.picture = csFull->picture;
      saveLumaCS.area.repositionTo(csFull->area);
      saveLumaCS.clearTUs();
      tmpTU = &saveLumaCS.addTU(currArea, partitioner.chType);
    }

    bool    cbfBestMode = false;
    bool    cbfBestModeValid = false;
    bool    cbfDCT2 = true;

#if JVET_Q0820_ACT
    if (m_pcEncCfg->getCostMode() != COST_LOSSLESS_CODING)
#endif
    m_pcRdCost->lambdaAdjustColorTrans(true, COMPONENT_Y);

#if JVET_Q0820_ACT
    for (int modeId = firstCheckId; modeId <= ((m_pcEncCfg->getCostMode() == COST_LOSSLESS_CODING) ? (nNumTransformCands - 1) : lastCheckId); modeId++)
#else
    for (int modeId = firstCheckId; modeId <= lastCheckId; modeId++)
#endif
    {
      uint8_t transformIndex = modeId;
      csFull->getResiBuf(tu.Y()).copyFrom(csFull->getOrgResiBuf(tu.Y()));

      m_CABACEstimator->getCtx() = ctxStart;
      m_CABACEstimator->resetBits();

      if (sps.getUseLFNST())
      {
        if ((transformIndex < lastCheckId) || ((transformIndex == lastCheckId) && !checkTransformSkip)) //we avoid this if the mode is transformSkip
        {
          // Skip checking other transform candidates if zero CBF is encountered and it is the best transform so far
          if (m_pcEncCfg->getUseFastLFNST() && transformIndex && !cbfBestMode && cbfBestModeValid)
          {
            continue;
          }
        }
      }
      else
      {
#if JVET_AHG14_LOSSLESS
        if (!(m_pcEncCfg->getCostMode() == COST_LOSSLESS_CODING))
        {
#endif
        if (!cbfDCT2 || (m_pcEncCfg->getUseTransformSkipFast() && bestLumaModeId == 1))
        {
          break;
        }
        if (!trModes[modeId].second)
        {
          continue;
        }
#if JVET_AHG14_LOSSLESS
        }
#endif
        tu.mtsIdx[COMPONENT_Y] = trModes[modeId].first;
      }

      singleDistTmpLuma = 0;
      if (sps.getUseLFNST())
      {
        if (cu.mtsFlag)
        {
          if (moreProbMTSIdxFirst)
          {
            uint32_t uiIntraMode = pu.intraDir[CHANNEL_TYPE_LUMA];

            if (transformIndex == 1)
            {
              tu.mtsIdx[COMPONENT_Y] = (uiIntraMode < 34) ? MTS_DST7_DCT8 : MTS_DCT8_DST7;
            }
            else if (transformIndex == 2)
            {
              tu.mtsIdx[COMPONENT_Y] = (uiIntraMode < 34) ? MTS_DCT8_DST7 : MTS_DST7_DCT8;
            }
            else
            {
              tu.mtsIdx[COMPONENT_Y] = MTS_DST7_DST7 + transformIndex;
            }
          }
          else
          {
            tu.mtsIdx[COMPONENT_Y] = MTS_DST7_DST7 + transformIndex;
          }
        }
        else
        {
          tu.mtsIdx[COMPONENT_Y] = transformIndex;
        }

        if (!cu.mtsFlag && checkTransformSkip)
        {
          xIntraCodingACTTUBlock(tu, COMPONENT_Y, singleDistTmpLuma, modeId == 0 ? &trModes : nullptr, true);
          if (modeId == 0)
          {
            for (int i = 0; i < 2; i++)
            {
              if (trModes[i].second)
              {
                lastCheckId = trModes[i].first;
              }
            }
          }
        }
        else
        {
          xIntraCodingACTTUBlock(tu, COMPONENT_Y, singleDistTmpLuma);
        }
      }
      else
      {
        if (nNumTransformCands > 1)
        {
          xIntraCodingACTTUBlock(tu, COMPONENT_Y, singleDistTmpLuma, modeId == 0 ? &trModes : nullptr, true);
          if (modeId == 0)
          {
            for (int i = 0; i < nNumTransformCands; i++)
            {
              if (trModes[i].second)
              {
                lastCheckId = trModes[i].first;
              }
            }
          }
        }
        else
        {
          xIntraCodingACTTUBlock(tu, COMPONENT_Y, singleDistTmpLuma);
        }
      }

#if JVET_Q0516_MTS_SIGNALLING_DC_ONLY_COND 
      CUCtx cuCtx;
      cuCtx.isDQPCoded = true;
      cuCtx.isChromaQpAdjCoded = true;
#endif
      //----- determine rate and r-d cost -----
      if ((sps.getUseLFNST() ? (modeId == lastCheckId && modeId != 0 && checkTransformSkip) : (trModes[modeId].first != 0)) && !TU::getCbfAtDepth(tu, COMPONENT_Y, currDepth))
      {
        //In order not to code TS flag when cbf is zero, the case for TS with cbf being zero is forbidden.
#if JVET_Q0820_ACT
        if (m_pcEncCfg->getCostMode() != COST_LOSSLESS_CODING)
#endif
        singleCostTmp = MAX_DOUBLE;
#if JVET_Q0820_ACT
        else
        {
          singleTmpFracBits = xGetIntraFracBitsQT(*csFull, partitioner, true, false, -1, TU_NO_ISP);
          singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma, false);
        }
#endif
      }
      else
      {
#if JVET_Q0516_MTS_SIGNALLING_DC_ONLY_COND 
        singleTmpFracBits = xGetIntraFracBitsQT(*csFull, partitioner, true, false, -1, TU_NO_ISP, &cuCtx);
        
        if (tu.mtsIdx[COMPONENT_Y] > MTS_SKIP)
        {
          if (!cuCtx.mtsLastScanPos)
          {
            singleCostTmp = MAX_DOUBLE;
          }
          else
          {
#if JVET_Q0820_ACT
            singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma, false);
#else
            singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma);
#endif
          }
        }
        else
#else
        singleTmpFracBits = xGetIntraFracBitsQT(*csFull, partitioner, true, false, -1, TU_NO_ISP);
#endif
#if JVET_Q0820_ACT
        singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma, false);
#else
        singleCostTmp = m_pcRdCost->calcRdCost(singleTmpFracBits, singleDistTmpLuma);
#endif
      }

      if (singleCostTmp < dSingleCostLuma)
      {
        dSingleCostLuma = singleCostTmp;
        validReturnFull = true;

        if (sps.getUseLFNST())
        {
          bestLumaModeId = modeId;
          cbfBestMode = TU::getCbfAtDepth(tu, COMPONENT_Y, currDepth);
          cbfBestModeValid = true;
        }
        else
        {
          bestLumaModeId = trModes[modeId].first;
          if (trModes[modeId].first == 0)
          {
            cbfDCT2 = TU::getCbfAtDepth(tu, COMPONENT_Y, currDepth);
          }
        }

        if (bestLumaModeId != lastCheckId)
        {
          saveLumaCS.getResiBuf(tu.Y()).copyFrom(csFull->getResiBuf(tu.Y()));
          tmpTU->copyComponentFrom(tu, COMPONENT_Y);
          ctxBest = m_CABACEstimator->getCtx();
        }
      }
    }

#if JVET_Q0820_ACT
    if (m_pcEncCfg->getCostMode() != COST_LOSSLESS_CODING)
#endif
    m_pcRdCost->lambdaAdjustColorTrans(false, COMPONENT_Y);

    if (sps.getUseLFNST())
    {
      if (!validReturnFull)
      {
        csFull->cost = MAX_DOUBLE;
        return false;
      }
    }
    else
    {
      CHECK(!validReturnFull, "no transform mode was tested for luma");
    }

    csFull->setDecomp(currArea.Y(), true);
    csFull->setDecomp(currArea.Cb(), true);

    if (bestLumaModeId != lastCheckId)
    {
      csFull->getResiBuf(tu.Y()).copyFrom(saveLumaCS.getResiBuf(tu.Y()));
      tu.copyComponentFrom(*tmpTU, COMPONENT_Y);
      m_CABACEstimator->getCtx() = ctxBest;
    }

    // 3 chroma residual optimization
    CodingStructure &saveChromaCS = *m_pSaveCS[1];
    saveChromaCS.pcv = csFull->pcv;
    saveChromaCS.picture = csFull->picture;