/src/vvenc/source/Lib/CommonLib/QuantRDOQ.cpp

Source
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/** \file     QuantRDOQ.cpp
    \brief    transform and quantization class
*/

#include "QuantRDOQ.h"
#include "UnitTools.h"
#include "ContextModelling.h"
#include "CodingStructure.h"
#include "dtrace_next.h"
#include "dtrace_buffer.h"

#include <stdlib.h>
#include <memory.h>

//! \ingroup CommonLib
//! \{

namespace vvenc {

struct coeffGroupRDStats
{
  int    iNNZbeforePos0;
  double d64CodedLevelandDist; // distortion and level cost only
  double d64UncodedDist;    // all zero coded block distortion
  double d64SigCost;
  double d64SigCost_0;
 int   iNumSbbCtxBins;
};


//! \ingroup CommonLib
//! \{

// ====================================================================================================================
// Constants
// ====================================================================================================================


// ====================================================================================================================
// Static functions
// ====================================================================================================================

// ====================================================================================================================
// QuantRDOQ class member functions
// ====================================================================================================================


QuantRDOQ::QuantRDOQ( const Quant* other, bool useScalingLists ) : Quant( other, useScalingLists )
{

  const QuantRDOQ *rdoq = dynamic_cast<const QuantRDOQ*>( other );
  CHECK( other && !rdoq, "The RDOQ cast must be successfull!" );
  xInitScalingList( rdoq );
}

QuantRDOQ::~QuantRDOQ()
{
  xDestroyScalingList();
}




/** Get the best level in RD sense
 *
 * \returns best quantized transform level for given scan position
 *
 * This method calculates the best quantized transform level for a given scan position.
 */
inline uint32_t QuantRDOQ::xGetCodedLevel( double&            rd64CodedCost,
                                       double&            rd64CodedCost0,
                                       double&            rd64CodedCostSig,
                                       Intermediate_Int   lLevelDouble,
                                       uint32_t               uiMaxAbsLevel,
                                       const BinFracBits* fracBitsSig,
                                       const BinFracBits& fracBitsPar,
                                       const BinFracBits& fracBitsGt1,
                                       const BinFracBits& fracBitsGt2,
                                       const int          remRegBins,
                                       unsigned           goRiceZero,
                                       uint16_t             ui16AbsGoRice,
                                       int                iQBits,
                                       double             errorScale,
                                       bool               bLast,
                                       const int          maxLog2TrDynamicRange
                                     ) const
{
  double dCurrCostSig   = 0;
  uint32_t   uiBestAbsLevel = 0;

  if( !bLast && uiMaxAbsLevel < 3 )
  {
    rd64CodedCostSig    = xGetRateSigCoef( *fracBitsSig, 0 );
    rd64CodedCost       = rd64CodedCost0 + rd64CodedCostSig;
    if( uiMaxAbsLevel == 0 )
    {
      return uiBestAbsLevel;
    }
  }
  else
  {
    rd64CodedCost       = MAX_DOUBLE;
  }

  if( !bLast )
  {
    dCurrCostSig        = xGetRateSigCoef( *fracBitsSig, 1 );
  }

  uint32_t uiMinAbsLevel    = ( uiMaxAbsLevel > 1 ? uiMaxAbsLevel - 1 : 1 );
  for( int uiAbsLevel  = uiMaxAbsLevel; uiAbsLevel >= uiMinAbsLevel ; uiAbsLevel-- )
  {
    double dErr         = double( lLevelDouble  - ( Intermediate_Int(uiAbsLevel) << iQBits ) );

    double dCurrCost    = dErr * dErr * errorScale + xGetICost( xGetICRate( uiAbsLevel, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, ui16AbsGoRice, maxLog2TrDynamicRange ) );
    dCurrCost          += dCurrCostSig;

    if( dCurrCost < rd64CodedCost )
    {
      uiBestAbsLevel    = uiAbsLevel;
      rd64CodedCost     = dCurrCost;
      rd64CodedCostSig  = dCurrCostSig;
    }
  }

  return uiBestAbsLevel;
}

/** Calculates the cost for specific absolute transform level
 * \param uiAbsLevel scaled quantized level
 * \param ui16CtxNumOne current ctxInc for coeff_abs_level_greater1 (1st bin of coeff_abs_level_minus1 in AVC)
 * \param ui16CtxNumAbs current ctxInc for coeff_abs_level_greater2 (remaining bins of coeff_abs_level_minus1 in AVC)
 * \param ui16AbsGoRice Rice parameter for coeff_abs_level_minus3
 * \param c1Idx
 * \param c2Idx
 * \param useLimitedPrefixLength
 * \param maxLog2TrDynamicRange
 * \returns cost of given absolute transform level
 */
inline int QuantRDOQ::xGetICRate( const uint32_t         uiAbsLevel,
                                  const BinFracBits& fracBitsPar,
                                  const BinFracBits& fracBitsGt1,
                                  const BinFracBits& fracBitsGt2,
                                  const int          remRegBins,
                                  unsigned           goRiceZero,
                                  const uint16_t       ui16AbsGoRice,
                                  const int          maxLog2TrDynamicRange  ) const
{
  if( remRegBins < 4 )
  {
    int       iRate   = int( xGetIEPRate() ); // cost of sign bit
    uint32_t  symbol  = ( uiAbsLevel == 0 ? goRiceZero : uiAbsLevel <= goRiceZero ? uiAbsLevel-1 : uiAbsLevel );
    uint32_t  length;
    const int threshold = COEF_REMAIN_BIN_REDUCTION;
    if( symbol < ( threshold << ui16AbsGoRice ) )
    {
      length = symbol >> ui16AbsGoRice;
      iRate += ( length + 1 + ui16AbsGoRice ) << SCALE_BITS;
    }
    else
    {
      length = ui16AbsGoRice;
      symbol = symbol - ( threshold << ui16AbsGoRice );
      while( symbol >= ( 1 << length ) )
      {
        symbol -= ( 1 << ( length++ ) );
      }
      iRate += ( threshold + length + 1 - ui16AbsGoRice + length ) << SCALE_BITS;
    }
    return iRate;
  }

  int iRate = int( xGetIEPRate() ); // cost of sign bit
  const uint32_t cthres = 4;
  if( uiAbsLevel >= cthres )
  {
    uint32_t symbol = ( uiAbsLevel - cthres ) >> 1;
    uint32_t length;
    const int threshold = COEF_REMAIN_BIN_REDUCTION;
    if( symbol < ( threshold << ui16AbsGoRice ) )
    {
      length = symbol >> ui16AbsGoRice;
      iRate += ( length + 1 + ui16AbsGoRice ) << SCALE_BITS;
    }
    else
    {
      length = ui16AbsGoRice;
      symbol = symbol - ( threshold << ui16AbsGoRice );
      while( symbol >= ( 1 << length ) )
      {
        symbol -= ( 1 << ( length++ ) );
      }
      iRate += ( threshold + length + 1 - ui16AbsGoRice + length ) << SCALE_BITS;
    }

    iRate += fracBitsGt1.intBits[1];
    iRate += fracBitsPar.intBits[( uiAbsLevel - 2 ) & 1];
    iRate += fracBitsGt2.intBits[1];
  }
  else if( uiAbsLevel == 1 )
  {
    iRate += fracBitsGt1.intBits[0];
  }
  else if( uiAbsLevel == 2 )
  {
    iRate += fracBitsGt1.intBits[1];
    iRate += fracBitsPar.intBits[0];
    iRate += fracBitsGt2.intBits[0];
  }
  else if( uiAbsLevel == 3 )
  {
    iRate += fracBitsGt1.intBits[1];
    iRate += fracBitsPar.intBits[1];
    iRate += fracBitsGt2.intBits[0];
  }
  else
  {
    iRate = 0;
  }
  return  iRate;
}

inline double QuantRDOQ::xGetRateSigCoeffGroup( const BinFracBits& fracBitsSigCG, unsigned uiSignificanceCoeffGroup ) const
{
  return xGetICost( fracBitsSigCG.intBits[uiSignificanceCoeffGroup] );
}

/** Calculates the cost of signaling the last significant coefficient in the block
 * \param uiPosX X coordinate of the last significant coefficient
 * \param uiPosY Y coordinate of the last significant coefficient
 * \param component colour component ID
 * \returns cost of last significant coefficient
 */
/*
 * \param uiWidth width of the transform unit (TU)
*/
inline double QuantRDOQ::xGetRateLast( const int* lastBitsX, const int* lastBitsY, unsigned PosX, unsigned PosY ) const
{
  uint32_t    CtxX  = g_uiGroupIdx[PosX];
  uint32_t    CtxY  = g_uiGroupIdx[PosY];
  double  Cost  = lastBitsX[ CtxX ] + lastBitsY[ CtxY ];
  if( CtxX > 3 )
  {
    Cost += xGetIEPRate() * ((CtxX-2)>>1);
  }
  if( CtxY > 3 )
  {
    Cost += xGetIEPRate() * ((CtxY-2)>>1);
  }
  return xGetICost( Cost );
}


inline double QuantRDOQ::xGetRateSigCoef( const BinFracBits& fracBitsSig, unsigned uiSignificance ) const
{
  return xGetICost( fracBitsSig.intBits[uiSignificance] );
}

/** Get the cost for a specific rate
 * \param dRate rate of a bit
 * \returns cost at the specific rate
 */
inline double QuantRDOQ::xGetICost        ( double                          dRate         ) const
{
  return m_dLambda * dRate;
}

/** Get the cost of an equal probable bit
 * \returns cost of equal probable bit
 */
inline double QuantRDOQ::xGetIEPRate() const
{
  return 32768;
}


double QuantRDOQ::xGetErrScaleCoeff(const bool needsSqrt2, SizeType width, SizeType height, int qp, const int maxLog2TrDynamicRange, const int channelBitDepth, bool bTransformSkip=false)
{
  const int iTransformShift = bTransformSkip ? 0 : getTransformShift(channelBitDepth, Size(width, height), maxLog2TrDynamicRange);
  double    dErrScale = (double)(1 << SCALE_BITS);                                // Compensate for scaling of bitcount in Lagrange cost function
  double    dTransShift = (double)iTransformShift + (needsSqrt2 ? -0.5 : 0.0);
  dErrScale = dErrScale * pow(2.0, (-2.0*dTransShift));                     // Compensate for scaling through forward transform
  const int  QStep = g_quantScales[needsSqrt2 ? 1 : 0][qp];
  double    finalErrScale = dErrScale / QStep / QStep / (1 << (DISTORTION_PRECISION_ADJUSTMENT(channelBitDepth) << 1));
  return    finalErrScale;
}



/** set error scale coefficients
 * \param list                   list ID
 * \param size
 * \param qp                     quantization parameter
 * \param maxLog2TrDynamicRange
 * \param bitDepths              reference to bit depth array for all channels
 */
void QuantRDOQ::xSetErrScaleCoeff( uint32_t list, uint32_t sizeX, uint32_t sizeY, int qp, const int maxLog2TrDynamicRange[MAX_NUM_CH], const BitDepths &bitDepths )
{
  const int width = g_scalingListSizeX[sizeX];
  const int height = g_scalingListSizeX[sizeY];
  const ChannelType channelType = ( ( list == 0 ) || ( list == MAX_NUM_COMP ) ) ? CH_L : CH_C;
  const int channelBitDepth = bitDepths[channelType];
  const int iTransformShift = getTransformShift( channelBitDepth, Size( g_scalingListSizeX[sizeX], g_scalingListSizeX[sizeY] ), maxLog2TrDynamicRange[channelType] );  // Represents scaling through forward transform

  double dErrScale = (double)( 1 << SCALE_BITS );                                // Compensate for scaling of bitcount in Lagrange cost function

  const bool needsSqrt2 = ((Log2(width*height)) & 1) == 1;
  double dTransShift = (double)iTransformShift + ( needsSqrt2 ? -0.5 : 0.0 );
  dErrScale = dErrScale*pow( 2.0, ( -2.0*dTransShift ) );                     // Compensate for scaling through forward transform

  if( getScalingListEnabled() )
  {
    uint32_t i, uiMaxNumCoeff = width * height;

    int*  piQuantcoeff = getQuantCoeff( list, qp, sizeX, sizeY );
    double* pdErrScale = xGetErrScaleCoeffSL( list, sizeX, sizeY, qp );

    for( i = 0; i < uiMaxNumCoeff; i++ )
    {
      pdErrScale[i] = dErrScale / piQuantcoeff[i] / piQuantcoeff[i] / (1 << (DISTORTION_PRECISION_ADJUSTMENT( bitDepths[channelType] ) << 1));
    }
  }

  int QStep = g_quantScales[needsSqrt2][qp];

  xGetErrScaleCoeffNoScalingList(list, sizeX, sizeY, qp) =
    dErrScale / QStep / QStep / (1 << (DISTORTION_PRECISION_ADJUSTMENT(bitDepths[channelType]) << 1));
}

/** set flat matrix value to quantized coefficient
 */
void QuantRDOQ::setFlatScalingList(const int maxLog2TrDynamicRange[MAX_NUM_CH], const BitDepths &bitDepths)
{
  Quant::setFlatScalingList( maxLog2TrDynamicRange, bitDepths );

  const int minimumQp = 0;
  const int maximumQp = SCALING_LIST_REM_NUM;

  for(uint32_t sizeX = 0; sizeX < SCALING_LIST_SIZE_NUM; sizeX++)
  {
    for(uint32_t sizeY = 0; sizeY < SCALING_LIST_SIZE_NUM; sizeY++)
    {
      for(uint32_t list = 0; list < SCALING_LIST_NUM; list++)
      {
        for(int qp = minimumQp; qp < maximumQp; qp++)
        {
          xSetErrScaleCoeff( list, sizeX, sizeY, qp, maxLog2TrDynamicRange, bitDepths );
        }
      }
    }
  }
}

/** initialization process of scaling list array
 */
void QuantRDOQ::xInitScalingList( const QuantRDOQ* other )
{
  m_isErrScaleListOwner = other == nullptr;

  bool useScalingLists = getScalingListEnabled();

  for(uint32_t sizeIdX = 0; sizeIdX < SCALING_LIST_SIZE_NUM; sizeIdX++)
  {
    for(uint32_t sizeIdY = 0; sizeIdY < SCALING_LIST_SIZE_NUM; sizeIdY++)
    {
      for(uint32_t qp = 0; qp < SCALING_LIST_REM_NUM; qp++)
      {
        for(uint32_t listId = 0; listId < SCALING_LIST_NUM; listId++)
        {
          if( m_isErrScaleListOwner )
          {
            m_errScale[sizeIdX][sizeIdY][listId][qp] = useScalingLists ? new double[g_scalingListSizeX[sizeIdX] * g_scalingListSizeX[sizeIdY]] : nullptr;
          }
          else
          {
            m_errScale[sizeIdX][sizeIdY][listId][qp] = other->m_errScale[sizeIdX][sizeIdY][listId][qp];
          }
        } // listID loop
      }
    }
  }
}

/** destroy quantization matrix array
 */
void QuantRDOQ::xDestroyScalingList()
{
  if( !m_isErrScaleListOwner ) return;

  for(uint32_t sizeIdX = 0; sizeIdX < SCALING_LIST_SIZE_NUM; sizeIdX++)
  {
    for(uint32_t sizeIdY = 0; sizeIdY < SCALING_LIST_SIZE_NUM; sizeIdY++)
    {
      for(uint32_t listId = 0; listId < SCALING_LIST_NUM; listId++)
      {
        for(uint32_t qp = 0; qp < SCALING_LIST_REM_NUM; qp++)
        {
          if(m_errScale[sizeIdX][sizeIdY][listId][qp])
          {
            delete [] m_errScale[sizeIdX][sizeIdY][listId][qp];
          }
        }
      }
    }
  }
//   Quant::destroyScalingList();
}


void QuantRDOQ::quant(TransformUnit& tu, const ComponentID compID, const CCoeffBuf& pSrc, TCoeff &uiAbsSum, const QpParam& cQP, const Ctx& ctx)
{
  const CompArea& rect       = tu.blocks[compID];
  const uint32_t uiWidth     = rect.width;
  const uint32_t uiHeight    = rect.height;

  const CCoeffBuf&  piCoef   = pSrc;
        CoeffSigBuf piQCoef  = tu.getCoeffs(compID);

  const bool useTransformSkip      = tu.mtsIdx[compID]==MTS_SKIP;

  bool useRDOQ = useTransformSkip ? m_useRDOQTS : m_RDOQ > 0;

  if( !tu.cu->ispMode || !isLuma(compID) )
  {
    useRDOQ &= uiWidth > 2;
    useRDOQ &= uiHeight > 2;
  }

  if( useRDOQ )
  {
    if (!tu.cs->picture->useSelectiveRdoq || xNeedRDOQ(tu, compID, piCoef, cQP))
    {
      if( useTransformSkip )
      {
        if(tu.cu->bdpcmM[toChannelType(compID)])
        {
          forwardRDPCM( tu, compID, pSrc, uiAbsSum, cQP, ctx );
        }
        else
        {
          rateDistOptQuantTS( tu, compID, pSrc, uiAbsSum, cQP, ctx );
        }
      }
      else
      {
        xRateDistOptQuant( tu, compID, pSrc, uiAbsSum, cQP, ctx );
      }
    }
    else
    {
      piQCoef.fill(0);
      uiAbsSum = 0;
      tu.lastPos[compID] = -1;
    }
  }
  else
  {
    Quant::quant( tu, compID, pSrc, uiAbsSum, cQP, ctx );
  }
}



void QuantRDOQ::xRateDistOptQuant(TransformUnit& tu, const ComponentID compID, const CCoeffBuf& pSrc, TCoeff &uiAbsSum, const QpParam& cQP, const Ctx &ctx)
{
  const FracBitsAccess& fracBits = ctx.getFracBitsAcess();

  const SPS &sps            = *tu.cs->sps;
  const CompArea& rect      = tu.blocks[compID];
  const uint32_t uiWidth    = rect.width;
  const uint32_t uiHeight   = rect.height;
  const ChannelType chType  = toChannelType(compID);
  const int channelBitDepth = sps.bitDepths[ chType ];

  const int  maxLog2TrDynamicRange = sps.getMaxLog2TrDynamicRange();

  const bool useIntraSubPartitions = tu.cu->ispMode && isLuma(compID);
  /* for 422 chroma blocks, the effective scaling applied during transformation is not a power of 2, hence it cannot be
  * implemented as a bit-shift (the quantised result will be sqrt(2) * larger than required). Alternatively, adjust the
  * uiLog2TrSize applied in iTransformShift, such that the result is 1/sqrt(2) the required result (i.e. smaller)
  * Then a QP+3 (sqrt(2)) or QP-3 (1/sqrt(2)) method could be used to get the required result
  */

  // Represents scaling through forward transform
  const int iTransformShift = getTransformShift(channelBitDepth, rect.size(), maxLog2TrDynamicRange);

  double     d64BlockUncodedCost               = 0;
  const uint32_t uiLog2BlockWidth                  = Log2(uiWidth);
  const uint32_t uiLog2BlockHeight                 = Log2(uiHeight);
  const uint32_t uiMaxNumCoeff                     = rect.area();

  CHECK(compID >= MAX_NUM_TBLOCKS, "Invalid component ID");

  int scalingListType = getScalingListType(tu.cu->predMode, compID);

  CHECK(scalingListType >= SCALING_LIST_NUM, "Invalid scaling list");

  const TCoeff    *plSrcCoeff = pSrc.buf;
        TCoeffSig *piDstCoeff = tu.getCoeffs(compID).buf;

  double *pdCostCoeff  = m_pdCostCoeff;
  double *pdCostSig    = m_pdCostSig;
  double *pdCostCoeff0 = m_pdCostCoeff0;
  int    *rateIncUp    = m_rateIncUp;
  int    *rateIncDown  = m_rateIncDown;
  int    *sigRateDelta = m_sigRateDelta;
  TCoeff *deltaU       = m_deltaU;

  memset( piDstCoeff,     0, sizeof( TCoeffSig ) * uiMaxNumCoeff );
  memset( m_pdCostCoeff,  0, sizeof( double ) *  uiMaxNumCoeff );
  memset( m_pdCostSig,    0, sizeof( double ) *  uiMaxNumCoeff );
  memset( m_rateIncUp,    0, sizeof( int    ) *  uiMaxNumCoeff );
  memset( m_rateIncDown,  0, sizeof( int    ) *  uiMaxNumCoeff );
  memset( m_sigRateDelta, 0, sizeof( int    ) *  uiMaxNumCoeff );
  memset( m_deltaU,       0, sizeof( TCoeff ) *  uiMaxNumCoeff );


  const bool   needSqrtAdjustment = TU::needsSqrt2Scale( tu, compID );
  const bool   isTransformSkip    = tu.mtsIdx[compID]==MTS_SKIP;
  const double *const pdErrScale  = xGetErrScaleCoeffSL(scalingListType, uiLog2BlockWidth, uiLog2BlockHeight, cQP.rem(isTransformSkip));
  const int    *const piQCoef     = getQuantCoeff(scalingListType, cQP.rem(isTransformSkip), uiLog2BlockWidth, uiLog2BlockHeight);
  const bool isLfnstApplied       = tu.cu->lfnstIdx > 0 && (CU::isSepTree(*tu.cu) ? true : isLuma(compID));
  const bool enableScalingLists   = getUseScalingList(uiWidth, uiHeight, isTransformSkip, isLfnstApplied);
  const int    defaultQuantisationCoefficient = g_quantScales[ needSqrtAdjustment ?1:0][cQP.rem(isTransformSkip)];
  const double defaultErrorScale              = xGetErrScaleCoeffNoScalingList(scalingListType, uiLog2BlockWidth, uiLog2BlockHeight, cQP.rem(isTransformSkip));
  const int iQBits = QUANT_SHIFT + cQP.per(isTransformSkip) + iTransformShift + (needSqrtAdjustment?-1:0);                   // Right shift of non-RDOQ quantizer;  level = (coeff*uiQ + offset)>>q_bits


  const TCoeff entropyCodingMinimum = -(1 << maxLog2TrDynamicRange);
  const TCoeff entropyCodingMaximum =  (1 << maxLog2TrDynamicRange) - 1;

  CoeffCodingContext cctx(tu, compID, tu.cs->slice->signDataHidingEnabled);
  const int    iCGSizeM1      = (1 << cctx.log2CGSize()) - 1;

  int     iCGLastScanPos      = -1;
  double  d64BaseCost         = 0;
  int     iLastScanPos        = -1;

  int ctxBinSampleRatio   = MAX_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT;
  int remRegBins          = (tu.getTbAreaAfterCoefZeroOut( compID ) * ctxBinSampleRatio) >> 4;
  uint32_t  goRiceParam   = 0;

  double *pdCostCoeffGroupSig = m_pdCostCoeffGroupSig;
  memset( pdCostCoeffGroupSig, 0, ( uiMaxNumCoeff >> cctx.log2CGSize() ) * sizeof( double ) );
  int iScanPos;
  coeffGroupRDStats rdStats;

#if ENABLE_TRACING
  DTRACE( g_trace_ctx, D_RDOQ, "%d: %3d, %3d, %dx%d, comp=%d\n", DTRACE_GET_COUNTER( g_trace_ctx, D_RDOQ ), rect.x, rect.y, rect.width, rect.height, compID );
#endif

  const uint32_t lfnstIdx = tu.cu->lfnstIdx;

  const int iCGNum = lfnstIdx > 0 ? 1 : std::min<int>(JVET_C0024_ZERO_OUT_TH, uiWidth) * std::min<int>(JVET_C0024_ZERO_OUT_TH, uiHeight) >> cctx.log2CGSize();

  for (int subSetId = iCGNum - 1; subSetId >= 0; subSetId--)
  {
    cctx.initSubblock( subSetId );

    int remRegBinsStartCG = remRegBins;

    uint32_t maxNonZeroPosInCG = iCGSizeM1;
    if( lfnstIdx > 0 && ( ( uiWidth == 4 && uiHeight == 4 ) || ( uiWidth == 8 && uiHeight == 8 && cctx.cgPosX() == 0 && cctx.cgPosY() == 0 ) ) )
    {
      maxNonZeroPosInCG = 7;
    }

    memset( &rdStats, 0, sizeof (coeffGroupRDStats));

    for( int iScanPosinCG = iCGSizeM1; iScanPosinCG > maxNonZeroPosInCG; iScanPosinCG-- )
    {
      iScanPos = cctx.minSubPos() + iScanPosinCG;
      uint32_t    blkPos = cctx.blockPos( iScanPos );
      piDstCoeff[ blkPos ] = 0;
    }
    for( int iScanPosinCG = maxNonZeroPosInCG; iScanPosinCG >= 0; iScanPosinCG-- )
    {
      iScanPos = cctx.minSubPos() + iScanPosinCG;
      //===== quantization =====
      uint32_t    uiBlkPos          = cctx.blockPos(iScanPos);

      // set coeff
      const int    quantisationCoefficient = (enableScalingLists) ? piQCoef   [uiBlkPos]               : defaultQuantisationCoefficient;
      const double errorScale              = (enableScalingLists) ? pdErrScale[uiBlkPos]               : defaultErrorScale;
      const int64_t  tmpLevel                = int64_t(abs(plSrcCoeff[ uiBlkPos ])) * quantisationCoefficient;

      const Intermediate_Int lLevelDouble  = (Intermediate_Int)std::min<int64_t>(tmpLevel, std::numeric_limits<Intermediate_Int>::max() - (Intermediate_Int(1) << (iQBits - 1)));

      uint32_t uiMaxAbsLevel        = std::min<uint32_t>(uint32_t(entropyCodingMaximum), uint32_t((lLevelDouble + (Intermediate_Int(1) << (iQBits - 1))) >> iQBits));

      const double dErr         = double( lLevelDouble );
      pdCostCoeff0[ iScanPos ]  = dErr * dErr * errorScale;
      d64BlockUncodedCost      += pdCostCoeff0[ iScanPos ];
      piDstCoeff[ uiBlkPos ]    = uiMaxAbsLevel;

      if ( uiMaxAbsLevel > 0 && iLastScanPos < 0 )
      {
        iLastScanPos            = iScanPos;
        iCGLastScanPos          = cctx.subSetId();
      }

      if ( iLastScanPos >= 0 )
      {

#if ENABLE_TRACING
        uint32_t uiCGPosY = cctx.cgPosY();
        uint32_t uiCGPosX = cctx.cgPosX();
        uint32_t uiPosY = cctx.posY( iScanPos );
        uint32_t uiPosX = cctx.posX( iScanPos );
        DTRACE( g_trace_ctx, D_RDOQ, "%d [%d][%d][%2d:%2d][%2d:%2d]", DTRACE_GET_COUNTER( g_trace_ctx, D_RDOQ ), iScanPos, uiBlkPos, uiCGPosX, uiCGPosY, uiPosX, uiPosY );
#endif
        //===== coefficient level estimation =====
        unsigned ctxIdSig = 0;
        if( iScanPos != iLastScanPos )
        {
          ctxIdSig = cctx.sigCtxIdAbs( iScanPos, piDstCoeff, 0 );
        }
        uint32_t    uiLevel;
        uint8_t ctxOffset     = cctx.ctxOffsetAbs     ();
        uint32_t    uiParCtx      = cctx.parityCtxIdAbs   ( ctxOffset );
        uint32_t    uiGt1Ctx      = cctx.greater1CtxIdAbs ( ctxOffset );
        uint32_t    uiGt2Ctx      = cctx.greater2CtxIdAbs ( ctxOffset );
        uint32_t    goRiceZero    = 0;
        if( remRegBins < 4 )
        {
          unsigned  sumAbs = cctx.templateAbsSum( iScanPos, piDstCoeff, 0 );
          goRiceParam             = g_auiGoRiceParsCoeff   [ sumAbs ];
          goRiceZero              = g_auiGoRicePosCoeff0(0, goRiceParam);
        }

        const BinFracBits fracBitsPar = fracBits.getFracBitsArray( uiParCtx );
        const BinFracBits fracBitsGt1 = fracBits.getFracBitsArray( uiGt1Ctx );
        const BinFracBits fracBitsGt2 = fracBits.getFracBitsArray( uiGt2Ctx );

        if( iScanPos == iLastScanPos )
        {
          uiLevel = xGetCodedLevel( pdCostCoeff[ iScanPos ], pdCostCoeff0[ iScanPos ], pdCostSig[ iScanPos ],
                                    lLevelDouble, uiMaxAbsLevel, nullptr, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, iQBits, errorScale, 1, maxLog2TrDynamicRange );
        }
        else
        {
          DTRACE_COND( ( uiMaxAbsLevel != 0 ), g_trace_ctx, D_RDOQ_MORE, " uiCtxSig=%d", ctxIdSig );

          const BinFracBits fracBitsSig = fracBits.getFracBitsArray( ctxIdSig );
          uiLevel = xGetCodedLevel( pdCostCoeff[ iScanPos ], pdCostCoeff0[ iScanPos ], pdCostSig[ iScanPos ],
                                    lLevelDouble, uiMaxAbsLevel, &fracBitsSig, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, iQBits, errorScale, 0, maxLog2TrDynamicRange );
          sigRateDelta[ uiBlkPos ] = ( remRegBins < 4 ? 0 : fracBitsSig.intBits[1] - fracBitsSig.intBits[0] );
        }

        DTRACE( g_trace_ctx, D_RDOQ, " Lev=%d \n", uiLevel );
        DTRACE_COND( ( uiMaxAbsLevel != 0 ), g_trace_ctx, D_RDOQ, " CostC0=%d\n", (int64_t)( pdCostCoeff0[iScanPos] ) );
        DTRACE_COND( ( uiMaxAbsLevel != 0 ), g_trace_ctx, D_RDOQ, " CostC =%d\n", (int64_t)( pdCostCoeff[iScanPos] ) );

        deltaU[ uiBlkPos ]        = TCoeff((lLevelDouble - (Intermediate_Int(uiLevel) << iQBits)) >> (iQBits-8));

        if( uiLevel > 0 )
        {
          int rateNow              = xGetICRate( uiLevel,   fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, maxLog2TrDynamicRange );
          rateIncUp   [ uiBlkPos ] = xGetICRate( uiLevel+1, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, maxLog2TrDynamicRange ) - rateNow;
          rateIncDown [ uiBlkPos ] = xGetICRate( uiLevel-1, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, maxLog2TrDynamicRange ) - rateNow;
        }
        else // uiLevel == 0
        {
          if( remRegBins < 4 )
          {
            int rateNow            = xGetICRate( uiLevel,   fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, maxLog2TrDynamicRange );
            rateIncUp [ uiBlkPos ] = xGetICRate( uiLevel+1, fracBitsPar, fracBitsGt1, fracBitsGt2, remRegBins, goRiceZero, goRiceParam, maxLog2TrDynamicRange ) - rateNow;
          }
          else
          {
            rateIncUp [ uiBlkPos ] = fracBitsGt1.intBits[ 0 ];
          }
        }
        piDstCoeff[ uiBlkPos ] = uiLevel;
        d64BaseCost           += pdCostCoeff [ iScanPos ];

        if( ( (iScanPos & iCGSizeM1) == 0 ) && ( iScanPos > 0 ) )
        {
          goRiceParam   = 0;
        }
        else if( remRegBins >= 4 )
        {
          int  sumAll = cctx.templateAbsSum(iScanPos, piDstCoeff, 4);
          goRiceParam = g_auiGoRiceParsCoeff[sumAll];
          remRegBins -= (uiLevel < 2 ? uiLevel : 3) + (iScanPos != iLastScanPos);
        }
      }
      else
      {
        d64BaseCost    += pdCostCoeff0[ iScanPos ];
      }
      rdStats.d64SigCost += pdCostSig[ iScanPos ];
      if (iScanPosinCG == 0 )
      {
        rdStats.d64SigCost_0 = pdCostSig[ iScanPos ];
      }
      if (piDstCoeff[ uiBlkPos ] )
      {
        cctx.setSigGroup();
        rdStats.d64CodedLevelandDist += pdCostCoeff[ iScanPos ] - pdCostSig[ iScanPos ];
        rdStats.d64UncodedDist += pdCostCoeff0[ iScanPos ];
        if ( iScanPosinCG != 0 )
        {
          rdStats.iNNZbeforePos0++;
        }
      }
    } //end for (iScanPosinCG)

    if (iCGLastScanPos >= 0)
    {
      if( cctx.subSetId() )
      {
        if( !cctx.isSigGroup() )
        {
          const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray( cctx.sigGroupCtxId() );
          d64BaseCost += xGetRateSigCoeffGroup(fracBitsSigGroup, 0) - rdStats.d64SigCost;
          pdCostCoeffGroupSig[ cctx.subSetId() ] = xGetRateSigCoeffGroup(fracBitsSigGroup, 0);
        }
        else
        {
          if (cctx.subSetId() < iCGLastScanPos) //skip the last coefficient group, which will be handled together with last position below.
          {
            if ( rdStats.iNNZbeforePos0 == 0 )
            {
              d64BaseCost -= rdStats.d64SigCost_0;
              rdStats.d64SigCost -= rdStats.d64SigCost_0;
            }
            // rd-cost if SigCoeffGroupFlag = 0, initialization
            double d64CostZeroCG = d64BaseCost;

            const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray( cctx.sigGroupCtxId() );

            if (cctx.subSetId() < iCGLastScanPos)
            {
              d64BaseCost  += xGetRateSigCoeffGroup(fracBitsSigGroup,1);
              d64CostZeroCG += xGetRateSigCoeffGroup(fracBitsSigGroup,0);
              pdCostCoeffGroupSig[ cctx.subSetId() ] = xGetRateSigCoeffGroup(fracBitsSigGroup,1);
            }

            // try to convert the current coeff group from non-zero to all-zero
            d64CostZeroCG += rdStats.d64UncodedDist;  // distortion for resetting non-zero levels to zero levels
            d64CostZeroCG -= rdStats.d64CodedLevelandDist;   // distortion and level cost for keeping all non-zero levels
            d64CostZeroCG -= rdStats.d64SigCost;     // sig cost for all coeffs, including zero levels and non-zerl levels

                                                     // if we can save cost, change this block to all-zero block
            if ( d64CostZeroCG < d64BaseCost )
            {
              cctx.resetSigGroup();
              d64BaseCost = d64CostZeroCG;
              remRegBins = remRegBinsStartCG;
              if (cctx.subSetId() < iCGLastScanPos)
              {
                pdCostCoeffGroupSig[ cctx.subSetId() ] = xGetRateSigCoeffGroup(fracBitsSigGroup,0);
              }
              // reset coeffs to 0 in this block
              for( int iScanPosinCG = maxNonZeroPosInCG; iScanPosinCG >= 0; iScanPosinCG-- )
              {
                iScanPos      = cctx.minSubPos() + iScanPosinCG;
                uint32_t uiBlkPos = cctx.blockPos( iScanPos );

                if (piDstCoeff[ uiBlkPos ])
                {
                  piDstCoeff [ uiBlkPos ] = 0;
                  pdCostCoeff[ iScanPos ] = pdCostCoeff0[ iScanPos ];
                  pdCostSig  [ iScanPos ] = 0;
                }
              }
            } // end if ( d64CostAllZeros < d64BaseCost )
          }
        } // end if if (uiSigCoeffGroupFlag[ uiCGBlkPos ] == 0)
      }
      else
      {
        cctx.setSigGroup();
      }
    }
  } //end for (cctx.subSetId)


  //===== estimate last position =====
  if ( iLastScanPos < 0 )
  {
    return;
  }

  double  d64BestCost         = 0;
  int     iBestLastIdxP1      = 0;


  if( !CU::isIntra( *tu.cu ) && isLuma( compID ) && tu.depth == 0 )
  {
    const BinFracBits fracBitsQtRootCbf = fracBits.getFracBitsArray( Ctx::QtRootCbf() );
    d64BestCost  = d64BlockUncodedCost + xGetICost( fracBitsQtRootCbf.intBits[ 0 ] );
    d64BaseCost += xGetICost( fracBitsQtRootCbf.intBits[ 1 ] );
  }
  else
  {
    bool previousCbf       = tu.cbf[COMP_Cb];
    bool lastCbfIsInferred = false;
    if( useIntraSubPartitions )
    {
      bool rootCbfSoFar       = false;
      bool isLastSubPartition = CU::isISPLast(*tu.cu, tu.Y(), compID);
      uint32_t nTus = tu.cu->ispMode == HOR_INTRA_SUBPARTITIONS ? tu.cu->lheight() >> Log2(tu.lheight()) : tu.cu->lwidth() >> Log2(tu.lwidth());
      if( isLastSubPartition )
      {
        TransformUnit* tuPointer = tu.cu->firstTU;
        for( int tuIdx = 0; tuIdx < nTus - 1; tuIdx++ )
        {
          rootCbfSoFar |= TU::getCbfAtDepth(*tuPointer, COMP_Y, tu.depth);
          tuPointer     = tuPointer->next;
        }
        if( !rootCbfSoFar )
        {
          lastCbfIsInferred = true;
        }
      }
      if( !lastCbfIsInferred )
      {
        previousCbf = TU::getPrevTuCbfAtDepth(tu, compID, tu.depth);
      }
    }
    BinFracBits fracBitsQtCbf = fracBits.getFracBitsArray( Ctx::QtCbf[compID]( DeriveCtx::CtxQtCbf( rect.compID, previousCbf, useIntraSubPartitions ) ) );

    if( !lastCbfIsInferred )
    {
      d64BestCost  = d64BlockUncodedCost + xGetICost(fracBitsQtCbf.intBits[0]);
      d64BaseCost += xGetICost(fracBitsQtCbf.intBits[1]);
    }
    else
    {
      d64BestCost  = d64BlockUncodedCost;
    }
  }

  int lastBitsX[LAST_SIGNIFICANT_GROUPS] = { 0 };
  int lastBitsY[LAST_SIGNIFICANT_GROUPS] = { 0 };
  {
    int dim1 = std::min<int>(JVET_C0024_ZERO_OUT_TH, uiWidth);
    int dim2 = std::min<int>(JVET_C0024_ZERO_OUT_TH, uiHeight);
    int bitsX = 0;
    int bitsY = 0;
    int ctxId;
    //X-coordinate
    for ( ctxId = 0; ctxId < g_uiGroupIdx[dim1-1]; ctxId++)
    {
      const BinFracBits fB = fracBits.getFracBitsArray( cctx.lastXCtxId(ctxId) );
      lastBitsX[ ctxId ]   = bitsX + fB.intBits[ 0 ];
      bitsX               +=         fB.intBits[ 1 ];
    }
    lastBitsX[ctxId] = bitsX;
    //Y-coordinate
    for ( ctxId = 0; ctxId < g_uiGroupIdx[dim2-1]; ctxId++)
    {
      const BinFracBits fB = fracBits.getFracBitsArray( cctx.lastYCtxId(ctxId) );
      lastBitsY[ ctxId ]   = bitsY + fB.intBits[ 0 ];
      bitsY               +=         fB.intBits[ 1 ];
    }
    lastBitsY[ctxId] = bitsY;
  }


  bool bFoundLast = false;
  for (int iCGScanPos = iCGLastScanPos; iCGScanPos >= 0; iCGScanPos--)
  {
    d64BaseCost -= pdCostCoeffGroupSig [ iCGScanPos ];
    if (cctx.isSigGroup( iCGScanPos ) )
    {
      uint32_t maxNonZeroPosInCG = iCGSizeM1;
      if( lfnstIdx > 0 && ( ( uiWidth == 4 && uiHeight == 4 ) || ( uiWidth == 8 && uiHeight == 8 && cctx.cgPosX() == 0 && cctx.cgPosY() == 0 ) ) )
      {
        maxNonZeroPosInCG = 7;
      }
      for( int iScanPosinCG = maxNonZeroPosInCG; iScanPosinCG >= 0; iScanPosinCG-- )
      {
        iScanPos = iCGScanPos * (iCGSizeM1 + 1) + iScanPosinCG;

        if (iScanPos > iLastScanPos)
        {
          continue;
        }
        uint32_t   uiBlkPos     = cctx.blockPos( iScanPos );

        if( piDstCoeff[ uiBlkPos ] )
        {
          uint32_t   uiPosY = uiBlkPos >> uiLog2BlockWidth;
          uint32_t   uiPosX = uiBlkPos - ( uiPosY << uiLog2BlockWidth );
          double d64CostLast  = xGetRateLast( lastBitsX, lastBitsY, uiPosX, uiPosY );

          double totalCost = d64BaseCost + d64CostLast - pdCostSig[ iScanPos ];

          if( totalCost < d64BestCost )
          {
            iBestLastIdxP1  = iScanPos + 1;
            d64BestCost     = totalCost;
          }
          if( piDstCoeff[ uiBlkPos ] > 1 )
          {
            bFoundLast = true;
            break;
          }
          d64BaseCost      -= pdCostCoeff[ iScanPos ];
          d64BaseCost      += pdCostCoeff0[ iScanPos ];
        }
        else
        {
          d64BaseCost      -= pdCostSig[ iScanPos ];
        }
      } //end for
      if (bFoundLast)
      {
        break;
      }
    } // end if (uiSigCoeffGroupFlag[ uiCGBlkPos ])
    DTRACE( g_trace_ctx, D_RDOQ_COST, "%d: %3d, %3d, %dx%d, comp=%d\n", DTRACE_GET_COUNTER( g_trace_ctx, D_RDOQ_COST ), rect.x, rect.y, rect.width, rect.height, compID );
    DTRACE( g_trace_ctx, D_RDOQ_COST, "Uncoded=%d\n", (int64_t)( d64BlockUncodedCost ) );
    DTRACE( g_trace_ctx, D_RDOQ_COST, "Coded  =%d\n", (int64_t)( d64BaseCost ) );

  } // end for


  for ( int scanPos = 0; scanPos < iBestLastIdxP1; scanPos++ )
  {
    int blkPos = cctx.blockPos( scanPos );
    TCoeff level = piDstCoeff[ blkPos ];
    uiAbsSum += level;
    piDstCoeff[ blkPos ] = ( plSrcCoeff[ blkPos ] < 0 ) ? -level : level;
  }

  //===== clean uncoded coefficients =====
  for ( int scanPos = iBestLastIdxP1; scanPos <= iLastScanPos; scanPos++ )
  {
    piDstCoeff[ cctx.blockPos( scanPos ) ] = 0;
  }
  iLastScanPos = iBestLastIdxP1 - 1;

  if( cctx.signHiding() && uiAbsSum>=2)
  {
    const double inverseQuantScale = double(g_invQuantScales[0][cQP.rem(isTransformSkip)]);
    int64_t rdFactor = (int64_t)(inverseQuantScale * inverseQuantScale * (1 << (2 * cQP.per(isTransformSkip))) / m_dLambda / 16
                                  / (1 << (2 * DISTORTION_PRECISION_ADJUSTMENT(channelBitDepth)))
                             + 0.5);

    int lastCG = -1;
    int absSum = 0 ;
    int n ;
    for (int subSet = iCGNum - 1; subSet >= 0; subSet--)
    {
      int  subPos         = subSet << cctx.log2CGSize();
      int  firstNZPosInCG = iCGSizeM1 + 1, lastNZPosInCG = -1;
      absSum = 0 ;

      for( n = iCGSizeM1; n >= 0; --n )
      {
        if( piDstCoeff[ cctx.blockPos( n + subPos )] )
        {
          lastNZPosInCG = n;
          break;
        }
      }

      for( n = 0; n <= iCGSizeM1; n++ )
      {
        if( piDstCoeff[ cctx.blockPos( n + subPos )] )
        {
          firstNZPosInCG = n;
          break;
        }
      }

      for( n = firstNZPosInCG; n <= lastNZPosInCG; n++ )
      {
        absSum += int(piDstCoeff[ cctx.blockPos( n + subPos )]);
      }

      if(lastNZPosInCG>=0 && lastCG==-1)
      {
        lastCG = 1;
      }

      if( lastNZPosInCG-firstNZPosInCG>=SBH_THRESHOLD )
      {
        uint32_t signbit = (piDstCoeff[cctx.blockPos(subPos+firstNZPosInCG)]>0?0:1);
        if( signbit!=(absSum&0x1) )  // hide but need tune
        {
          // calculate the cost
          int64_t minCostInc = std::numeric_limits<int64_t>::max(), curCost = std::numeric_limits<int64_t>::max();
          int minPos = -1, finalChange = 0, curChange = 0;

          for( n = (lastCG == 1 ? lastNZPosInCG : iCGSizeM1); n >= 0; --n )
          {
            uint32_t uiBlkPos   = cctx.blockPos( n + subPos );
            if(piDstCoeff[ uiBlkPos ] != 0 )
            {
              int64_t costUp   = rdFactor * ( - deltaU[uiBlkPos] ) + rateIncUp[uiBlkPos];
              int64_t costDown = rdFactor * (   deltaU[uiBlkPos] ) + rateIncDown[uiBlkPos]
                -   ((abs(piDstCoeff[uiBlkPos]) == 1) ? sigRateDelta[uiBlkPos] : 0);

              if(lastCG==1 && lastNZPosInCG==n && abs(piDstCoeff[uiBlkPos])==1)
              {
                costDown -= (4<<SCALE_BITS);
              }

              if(costUp<costDown)
              {
                curCost = costUp;
                curChange =  1;
              }
              else
              {
                curChange = -1;
                if(n==firstNZPosInCG && abs(piDstCoeff[uiBlkPos])==1)
                {
                  curCost = std::numeric_limits<int64_t>::max();
                }
                else
                {
                  curCost = costDown;
                }
              }
            }
            else
            {
              curCost = rdFactor * ( - (abs(deltaU[uiBlkPos])) ) + (1<<SCALE_BITS) + rateIncUp[uiBlkPos] + sigRateDelta[uiBlkPos] ;
              curChange = 1 ;

              if(n<firstNZPosInCG)
              {
                uint32_t thissignbit = (plSrcCoeff[uiBlkPos]>=0?0:1);
                if(thissignbit != signbit )
                {
                  curCost = std::numeric_limits<int64_t>::max();
                }
              }
            }

            if( curCost<minCostInc)
            {
              minCostInc = curCost;
              finalChange = curChange;
              minPos = uiBlkPos;
            }
          }

          if(piDstCoeff[minPos] == entropyCodingMaximum || piDstCoeff[minPos] == entropyCodingMinimum)
          {
            finalChange = -1;
          }

          if(plSrcCoeff[minPos]>=0)
          {
            piDstCoeff[minPos] += finalChange ;
          }
          else
          {
            piDstCoeff[minPos] -= finalChange ;
          }
        }
      }

      if(lastCG==1)
      {
        lastCG=0 ;
      }
    }

    // Check due to saving of last pos. Sign data hiding can change the position of last coef.
    if( piDstCoeff[cctx.blockPos( iLastScanPos )] == 0 )
    {
      int scanPos = iLastScanPos - 1;
      for( ; scanPos >= 0; scanPos-- )
      {
        if( piDstCoeff[cctx.blockPos( scanPos )] )
          break;
      }
      iLastScanPos = scanPos;
    }
  }
  tu.lastPos[compID] = iLastScanPos;
}

void QuantRDOQ::rateDistOptQuantTS( TransformUnit& tu, const ComponentID compID, const CCoeffBuf& coeffs, TCoeff &absSum, const QpParam& qp, const Ctx &ctx )
{
  const FracBitsAccess& fracBits = ctx.getFracBitsAcess();

  const SPS &sps            = *tu.cs->sps;
  const CompArea& rect      = tu.blocks[compID];
  const uint32_t width      = rect.width;
  const uint32_t height     = rect.height;
  const ChannelType chType  = toChannelType(compID);
  const int channelBitDepth = sps.bitDepths[ chType ];

  const int  maxLog2TrDynamicRange = sps.getMaxLog2TrDynamicRange();

  const int transformShift = getTransformShift( channelBitDepth, rect.size(), maxLog2TrDynamicRange );

  const uint32_t maxNumCoeff                        = rect.area();

  CHECK( compID >= MAX_NUM_TBLOCKS, "Invalid component ID" );

  int scalingListType = getScalingListType( tu.cu->predMode, compID );
  CHECK( scalingListType >= SCALING_LIST_NUM, "Invalid scaling list" );

  const TCoeff    *srcCoeff = coeffs.buf;
        TCoeffSig *dstCoeff = tu.getCoeffs( compID ).buf;

  double *costCoeff  = m_pdCostCoeff;
  double *costSig    = m_pdCostSig;
  double *costCoeff0 = m_pdCostCoeff0;

  memset( m_pdCostCoeff,  0, sizeof( double ) *  maxNumCoeff );
  memset( m_pdCostSig,    0, sizeof( double ) *  maxNumCoeff );

  m_bdpcm = 0;

  const bool   needsSqrt2Scale = TU::needsSqrt2Scale( tu, compID );  // should always be false - transform-skipped blocks don't require sqrt(2) compensation.
  const bool   isTransformSkip = tu.mtsIdx[compID]==MTS_SKIP;
  const int    qBits = QUANT_SHIFT + qp.per(isTransformSkip) + (isTransformSkip ? 0 : transformShift) + (needsSqrt2Scale ? -1 : 0);  // Right shift of non-RDOQ quantizer;  level = (coeff*uiQ + offset)>>q_bits
  const int    quantisationCoefficient = g_quantScales[needsSqrt2Scale?1:0][qp.rem(isTransformSkip)];
  const double errorScale              = xGetErrScaleCoeff( TU::needsSqrt2Scale(tu, compID), width, height, qp.rem(isTransformSkip), maxLog2TrDynamicRange, channelBitDepth, isTransformSkip);

  const TCoeff entropyCodingMaximum = ( 1 << maxLog2TrDynamicRange ) - 1;

  uint32_t coeffLevels[3];
  double   coeffLevelError[4];

  CoeffCodingContext cctx( tu, compID, tu.cs->slice->signDataHidingEnabled );
  const int sbSizeM1    = ( 1 << cctx.log2CGSize() ) - 1;
  double    baseCost    = 0;
  uint32_t  goRiceParam = 0;

  double *costSigSubBlock = m_pdCostCoeffGroupSig;
  memset( costSigSubBlock, 0, ( maxNumCoeff >> cctx.log2CGSize() ) * sizeof( double ) );

  const int sbNum = width * height >> cctx.log2CGSize();
  int scanPos;
  coeffGroupRDStats rdStats;

  bool anySigCG = false;

  int maxCtxBins = (cctx.maxNumCoeff() * 7) >> 2;
  cctx.remRegBins = maxCtxBins;

  for( int sbId = 0; sbId < sbNum; sbId++ )
  {
    cctx.initSubblock( sbId );

    int noCoeffCoded = 0;
    baseCost = 0.0;
    memset( &rdStats, 0, sizeof (coeffGroupRDStats));

    rdStats.iNumSbbCtxBins = 0;

    for( int scanPosInSB = 0; scanPosInSB <= sbSizeM1; scanPosInSB++ )
    {
      int lastPosCoded = sbSizeM1;
      scanPos = cctx.minSubPos() + scanPosInSB;
      //===== quantization =====
      uint32_t blkPos = cctx.blockPos( scanPos );

      // set coeff
      const int64_t          tmpLevel    = int64_t( abs( srcCoeff[blkPos] ) ) * quantisationCoefficient;
      const Intermediate_Int levelDouble = (Intermediate_Int)std::min<int64_t>( tmpLevel, std::numeric_limits<Intermediate_Int>::max() - ( Intermediate_Int( 1 ) << ( qBits - 1 ) ) );

      uint32_t roundAbsLevel = std::min<uint32_t>(uint32_t(entropyCodingMaximum), uint32_t((levelDouble + (Intermediate_Int(1) << (qBits - 1))) >> qBits));
      uint32_t minAbsLevel = (roundAbsLevel > 1 ? roundAbsLevel - 1 : 1);

      uint32_t downAbsLevel = std::min<uint32_t>(uint32_t(entropyCodingMaximum), uint32_t(levelDouble >> qBits));
      uint32_t upAbsLevel = std::min<uint32_t>(uint32_t(entropyCodingMaximum), downAbsLevel + 1);

      m_testedLevels = 0;
      coeffLevels[m_testedLevels++] = roundAbsLevel;

      if (minAbsLevel != roundAbsLevel)
        coeffLevels[m_testedLevels++] = minAbsLevel;

      int rightPixel, belowPixel, predPixel;

      cctx.neighTS(rightPixel, belowPixel, scanPos, dstCoeff);
      predPixel = cctx.deriveModCoeff(rightPixel, belowPixel, upAbsLevel, 0);

      if (upAbsLevel != roundAbsLevel && upAbsLevel != minAbsLevel && predPixel == 1)
        coeffLevels[m_testedLevels++] = upAbsLevel;

      double dErr = double(levelDouble);
      coeffLevelError[0] = dErr * dErr * errorScale;

      costCoeff0[scanPos] = coeffLevelError[0];
      dstCoeff[blkPos]    = coeffLevels[0];

      //===== coefficient level estimation =====
            unsigned    ctxIdSig = cctx.sigCtxIdAbsTS( scanPos, dstCoeff );
            uint32_t    cLevel;
      const BinFracBits fracBitsPar = fracBits.getFracBitsArray( cctx.parityCtxIdAbsTS() );

      //goRiceParam = cctx.templateAbsSumTS( scanPos, dstCoeff );
      goRiceParam = 1;
      unsigned ctxIdSign = cctx.signCtxIdAbsTS(scanPos, dstCoeff, 0);
      const BinFracBits fracBitsSign = fracBits.getFracBitsArray(ctxIdSign);
      const uint8_t     sign         = srcCoeff[ blkPos ] < 0 ? 1 : 0;

      DTRACE_COND( ( coeffLevels[0] != 0 ), g_trace_ctx, D_RDOQ_MORE, " uiCtxSig=%d", ctxIdSig );

      unsigned gt1CtxId = cctx.lrg1CtxIdAbsTS(scanPos, dstCoeff, 0);
      const BinFracBits fracBitsGr1 = fracBits.getFracBitsArray(gt1CtxId);

      const BinFracBits fracBitsSig = fracBits.getFracBitsArray( ctxIdSig );
      bool lastCoeff = false; //
      if (scanPosInSB == lastPosCoded && noCoeffCoded == 0)
      {
        lastCoeff = true;
      }
      int numUsedCtxBins = 0;
      cLevel = xGetCodedLevelTSPred(costCoeff[scanPos], costCoeff0[scanPos], costSig[scanPos], levelDouble, qBits, errorScale, coeffLevels, coeffLevelError,
                                    &fracBitsSig, fracBitsPar, cctx, fracBits, fracBitsSign, fracBitsGr1, sign, rightPixel, belowPixel, goRiceParam, lastCoeff, maxLog2TrDynamicRange, numUsedCtxBins);

      cctx.remRegBins -= numUsedCtxBins;
      rdStats.iNumSbbCtxBins += numUsedCtxBins;

      if (cLevel > 0)
      {
        noCoeffCoded++;
      }

      TCoeff level = cLevel;
      dstCoeff[blkPos] = (level != 0 && srcCoeff[blkPos] < 0) ? -level : level;
      baseCost           += costCoeff[ scanPos ];
      rdStats.d64SigCost += costSig[ scanPos ];

      if( dstCoeff[ blkPos ] )
      {
        cctx.setSigGroup();
        rdStats.d64CodedLevelandDist += costCoeff [ scanPos ] - costSig[ scanPos ];
        rdStats.d64UncodedDist       += costCoeff0[ scanPos ];
      }
    } //end for (iScanPosinCG)

    if( !cctx.isSigGroup() )
    {
      const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray( cctx.sigGroupCtxId( true ) );
      baseCost += xGetRateSigCoeffGroup( fracBitsSigGroup, 0 ) - rdStats.d64SigCost;
      costSigSubBlock[cctx.subSetId()] = xGetRateSigCoeffGroup( fracBitsSigGroup, 0 );
      cctx.remRegBins += rdStats.iNumSbbCtxBins; // skip sub-block
    }
    else if( sbId != sbNum - 1 || anySigCG )
    {
      // rd-cost if SigCoeffGroupFlag = 0, initialization
      double costZeroSB = baseCost;

      const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray( cctx.sigGroupCtxId( true ) );

      baseCost   += xGetRateSigCoeffGroup( fracBitsSigGroup, 1 );
      costZeroSB += xGetRateSigCoeffGroup( fracBitsSigGroup, 0 );
      costSigSubBlock[ cctx.subSetId() ] = xGetRateSigCoeffGroup( fracBitsSigGroup, 1 );

      costZeroSB += rdStats.d64UncodedDist;         // distortion for resetting non-zero levels to zero levels
      costZeroSB -= rdStats.d64CodedLevelandDist;   // distortion and level cost for keeping all non-zero levels
      costZeroSB -= rdStats.d64SigCost;             // sig cost for all coeffs, including zero levels and non-zerl levels

      if( costZeroSB < baseCost )
      {
        cctx.resetSigGroup();
        baseCost = costZeroSB;
        costSigSubBlock[ cctx.subSetId() ] = xGetRateSigCoeffGroup( fracBitsSigGroup, 0 );
        cctx.remRegBins += rdStats.iNumSbbCtxBins; // skip sub-block

        for( int scanPosInSB = 0; scanPosInSB <= sbSizeM1; scanPosInSB++ )
        {
          scanPos = cctx.minSubPos() + scanPosInSB;
          uint32_t blkPos = cctx.blockPos( scanPos );

          if( dstCoeff[ blkPos ] )
          {
            dstCoeff[ blkPos ] = 0;
            costCoeff[ scanPos ] = costCoeff0[ scanPos ];
            costSig[ scanPos] = 0;
          }
        }
      }
      else
      {
        anySigCG = true;
      }
    }
  }

  //===== estimate last position =====
  for( int scanPos = 0; scanPos < maxNumCoeff; scanPos++ )
  {
    int blkPos = cctx.blockPos( scanPos );
    TCoeff level = dstCoeff[ blkPos ];
    absSum += abs(level);
  }
}

void QuantRDOQ::forwardRDPCM( TransformUnit& tu, const ComponentID compID, const CCoeffBuf& coeffs, TCoeff &absSum, const QpParam& qp, const Ctx &ctx )
{
  const FracBitsAccess& fracBits = ctx.getFracBitsAcess();

  const SPS &sps = *tu.cs->sps;
  const CompArea& rect = tu.blocks[compID];
  const uint32_t width = rect.width;
  const uint32_t height = rect.height;
  const ChannelType chType = toChannelType(compID);
  const int channelBitDepth = sps.bitDepths[chType];

  const int  maxLog2TrDynamicRange = sps.getMaxLog2TrDynamicRange();
  const int  dirMode = tu.cu->bdpcmM[toChannelType(compID)];

  const int transformShift = getTransformShift(channelBitDepth, rect.size(), maxLog2TrDynamicRange);

  const uint32_t maxNumCoeff = rect.area();

  CHECK(compID >= MAX_NUM_TBLOCKS, "Invalid component ID");

  int scalingListType = getScalingListType(tu.cu->predMode, compID);
  CHECK(scalingListType >= SCALING_LIST_NUM, "Invalid scaling list");

  const TCoeff    *srcCoeff = coeffs.buf;
        TCoeffSig *dstCoeff = tu.getCoeffs(compID).buf;

  double *costCoeff = m_pdCostCoeff;
  double *costSig = m_pdCostSig;
  double *costCoeff0 = m_pdCostCoeff0;

  memset(m_pdCostCoeff, 0, sizeof(double) *  maxNumCoeff);
  memset(m_pdCostSig, 0, sizeof(double) *  maxNumCoeff);
  memset(m_fullCoeff, 0, sizeof(TCoeff) * maxNumCoeff);

  m_bdpcm = dirMode;

  const bool   needsSqrt2Scale = TU::needsSqrt2Scale(tu, compID);  // should always be false - transform-skipped blocks don't require sqrt(2) compensation.
  const bool   isTransformSkip = tu.mtsIdx[compID]==MTS_SKIP;
  const int    qBits = QUANT_SHIFT + qp.per(isTransformSkip) + (isTransformSkip? 0 : transformShift) + ( needsSqrt2Scale ? -1 : 0);  // Right shift of non-RDOQ quantizer;  level = (coeff*uiQ + offset)>>q_bits
  const int    quantisationCoefficient = g_quantScales[needsSqrt2Scale ? 1 : 0][qp.rem(isTransformSkip)];
  const double errorScale = xGetErrScaleCoeff(TU::needsSqrt2Scale(tu, compID), width, height, qp.rem(isTransformSkip), maxLog2TrDynamicRange, channelBitDepth, isTransformSkip);

  TrQuantParams trQuantParams;
  trQuantParams.rightShift = (IQUANT_SHIFT - ((isTransformSkip ? 0 : transformShift) + qp.per(isTransformSkip)));
  trQuantParams.qScale = g_invQuantScales[needsSqrt2Scale ? 1 : 0][qp.rem(isTransformSkip)];

  const TCoeff entropyCodingMaximum = (1 << maxLog2TrDynamicRange) - 1;

  uint32_t coeffLevels[3];
  double   coeffLevelError[4];

  CoeffCodingContext cctx(tu, compID, tu.cs->slice->signDataHidingEnabled);
  const int sbSizeM1 = (1 << cctx.log2CGSize()) - 1;
  double    baseCost = 0;
  uint32_t  goRiceParam = 0;

  double *costSigSubBlock = m_pdCostCoeffGroupSig;
  memset(costSigSubBlock, 0, (maxNumCoeff >> cctx.log2CGSize()) * sizeof(double));

  const int sbNum = width * height >> cctx.log2CGSize();
  int scanPos;
  coeffGroupRDStats rdStats;

  bool anySigCG = false;

  int maxCtxBins = (cctx.maxNumCoeff() * 7) >> 2;
  cctx.remRegBins = maxCtxBins;

  for (int sbId = 0; sbId < sbNum; sbId++)
  {
    cctx.initSubblock(sbId);

    int noCoeffCoded = 0;
    baseCost = 0.0;
    memset(&rdStats, 0, sizeof(coeffGroupRDStats));
    rdStats.iNumSbbCtxBins = 0;

    for (int scanPosInSB = 0; scanPosInSB <= sbSizeM1; scanPosInSB++)
    {
      int lastPosCoded = sbSizeM1;
      scanPos = cctx.minSubPos() + scanPosInSB;
      //===== quantization =====
      uint32_t blkPos = cctx.blockPos(scanPos);

      const int posX = cctx.posX(scanPos);
      const int posY = cctx.posY(scanPos);
      const int posS = (1 == dirMode) ? posX : posY;
      const int posNb = (1 == dirMode) ? (posX - 1) + posY * coeffs.stride : posX + (posY - 1) * coeffs.stride;
      TCoeff predCoeff = (0 != posS) ? m_fullCoeff[posNb] : 0;

      // set coeff
      const int64_t          tmpLevel = int64_t(abs(srcCoeff[blkPos] - predCoeff)) * quantisationCoefficient;
      const Intermediate_Int levelDouble = (Intermediate_Int)std::min<int64_t>(tmpLevel, std::numeric_limits<Intermediate_Int>::max() - (Intermediate_Int(1) << (qBits - 1)));
      uint32_t roundAbsLevel = std::min<uint32_t>(uint32_t(entropyCodingMaximum), uint32_t((levelDouble + (Intermediate_Int(1) << (qBits - 1))) >> qBits));
      uint32_t minAbsLevel = (roundAbsLevel > 1 ? roundAbsLevel - 1 : 1);

      m_testedLevels = 0;
      coeffLevels[m_testedLevels++] = roundAbsLevel;

      if (minAbsLevel != roundAbsLevel)
        coeffLevels[m_testedLevels++] = minAbsLevel;

      double dErr = double(levelDouble);
      coeffLevelError[0]  = dErr * dErr * errorScale;

      costCoeff0[scanPos] = coeffLevelError[0];
      dstCoeff[blkPos]    = coeffLevels[0];

      //===== coefficient level estimation =====
      unsigned    ctxIdSig = cctx.sigCtxIdAbsTS(scanPos, dstCoeff);
      uint32_t    cLevel;
      const BinFracBits fracBitsPar = fracBits.getFracBitsArray(cctx.parityCtxIdAbsTS());

      //goRiceParam = cctx.templateAbsSumTS(scanPos, dstCoeff);
      goRiceParam = 1;
      unsigned ctxIdSign = cctx.signCtxIdAbsTS(scanPos, dstCoeff, dirMode);
      const BinFracBits fracBitsSign = fracBits.getFracBitsArray(ctxIdSign);
      const uint8_t     sign = srcCoeff[blkPos] - predCoeff < 0 ? 1 : 0;
      unsigned gt1CtxId = cctx.lrg1CtxIdAbsTS(scanPos, dstCoeff, dirMode);
      const BinFracBits fracBitsGr1 = fracBits.getFracBitsArray(gt1CtxId);

      DTRACE_COND((dstCoeff[blkPos] != 0), g_trace_ctx, D_RDOQ_MORE, " uiCtxSig=%d", ctxIdSig);

      const BinFracBits fracBitsSig = fracBits.getFracBitsArray(ctxIdSig);
      bool lastCoeff = false; //
      if (scanPosInSB == lastPosCoded && noCoeffCoded == 0)
      {
        lastCoeff = true;
      }
      int rightPixel, belowPixel;
      cctx.neighTS(rightPixel, belowPixel, scanPos, dstCoeff);
      int numUsedCtxBins = 0;
      cLevel = xGetCodedLevelTSPred(costCoeff[scanPos], costCoeff0[scanPos], costSig[scanPos], levelDouble, qBits, errorScale, coeffLevels, coeffLevelError,
        &fracBitsSig, fracBitsPar, cctx, fracBits, fracBitsSign, fracBitsGr1, sign, rightPixel, belowPixel, goRiceParam, lastCoeff, maxLog2TrDynamicRange, numUsedCtxBins);
      cctx.remRegBins -= numUsedCtxBins;
      rdStats.iNumSbbCtxBins += numUsedCtxBins;

      if (cLevel > 0)
      {
        noCoeffCoded++;
      }
      dstCoeff[blkPos] = cLevel;

      if (sign)
      {
        dstCoeff[blkPos] = -dstCoeff[blkPos];
      }

      xDequantSample( m_fullCoeff[blkPos], dstCoeff[blkPos], trQuantParams );
      m_fullCoeff[blkPos] += predCoeff;

      baseCost += costCoeff[scanPos];
      rdStats.d64SigCost += costSig[scanPos];

      if (dstCoeff[blkPos])
      {
        cctx.setSigGroup();
        rdStats.d64CodedLevelandDist += costCoeff[scanPos] - costSig[scanPos];
        rdStats.d64UncodedDist += costCoeff0[scanPos];
      }
    } //end for (iScanPosinCG)

    if (!cctx.isSigGroup())
    {
      const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray(cctx.sigGroupCtxId(true));
      baseCost += xGetRateSigCoeffGroup(fracBitsSigGroup, 0) - rdStats.d64SigCost;
      costSigSubBlock[cctx.subSetId()] = xGetRateSigCoeffGroup(fracBitsSigGroup, 0);
      cctx.remRegBins += rdStats.iNumSbbCtxBins; // skip sub-block
    }
    else if (sbId != sbNum - 1 || anySigCG)
    {
      // rd-cost if SigCoeffGroupFlag = 0, initialization
      double costZeroSB = baseCost;

      const BinFracBits fracBitsSigGroup = fracBits.getFracBitsArray(cctx.sigGroupCtxId(true));

      baseCost += xGetRateSigCoeffGroup(fracBitsSigGroup, 1);
      costZeroSB += xGetRateSigCoeffGroup(fracBitsSigGroup, 0);
      costSigSubBlock[cctx.subSetId()] = xGetRateSigCoeffGroup(fracBitsSigGroup, 1);

      costZeroSB += rdStats.d64UncodedDist;         // distortion for resetting non-zero levels to zero levels
      costZeroSB -= rdStats.d64CodedLevelandDist;   // distortion and level cost for keeping all non-zero levels
      costZeroSB -= rdStats.d64SigCost;             // sig cost for all coeffs, including zero levels and non-zerl levels

      if (costZeroSB < baseCost)
      {
        cctx.resetSigGroup();
        baseCost = costZeroSB;
        costSigSubBlock[cctx.subSetId()] = xGetRateSigCoeffGroup(fracBitsSigGroup, 0);
        cctx.remRegBins += rdStats.iNumSbbCtxBins; // skip sub-block

        for (int scanPosInSB = 0; scanPosInSB <= sbSizeM1; scanPosInSB++)
        {
          scanPos = cctx.minSubPos() + scanPosInSB;
          uint32_t blkPos = cctx.blockPos(scanPos);

          const int posX = cctx.posX(scanPos);
          const int posY = cctx.posY(scanPos);
          const int posS = (1 == dirMode) ? posX : posY;
          const int posNb = (1 == dirMode) ? (posX - 1) + posY * coeffs.stride : posX + (posY - 1) * coeffs.stride;
          m_fullCoeff[scanPos] = (0 != posS) ? m_fullCoeff[posNb] : 0;

          if (dstCoeff[blkPos])
          {
            dstCoeff[blkPos] = 0;
            costCoeff[scanPos] = costCoeff0[scanPos];
            costSig[scanPos] = 0;
          }
        }
      }
      else
      {
        anySigCG = true;
      }
    }
  }

  //===== estimate last position =====
  for (int scanPos = 0; scanPos < maxNumCoeff; scanPos++)
  {
    int blkPos = cctx.blockPos(scanPos);
    TCoeff level = dstCoeff[blkPos];
    absSum += abs(level);
  }
}

void QuantRDOQ::xDequantSample(TCoeff& pRes, TCoeffSig& coeff, const TrQuantParams& trQuantParams)
{
  // xDequant
  if (trQuantParams.rightShift > 0)
  {
    const Intermediate_Int qAdd = Intermediate_Int(1) << (trQuantParams.rightShift - 1);
    pRes = TCoeff((Intermediate_Int(coeff) * trQuantParams.qScale + qAdd) >> trQuantParams.rightShift);
  }
  else
  {
    pRes = TCoeff((Intermediate_Int(coeff) * trQuantParams.qScale) *(1<< -trQuantParams.rightShift));
  }
}

inline uint32_t QuantRDOQ::xGetCodedLevelTSPred(double&            rd64CodedCost,
  double&            rd64CodedCost0,
  double&            rd64CodedCostSig,
  Intermediate_Int    levelDouble,
  int                 qBits,
  double              errorScale,
  uint32_t coeffLevels[],
  double coeffLevelError[],
  const BinFracBits* fracBitsSig,
  const BinFracBits& fracBitsPar,
  CoeffCodingContext& cctx,
  const FracBitsAccess& fracBitsAccess,
  const BinFracBits& fracBitsSign,
  const BinFracBits& fracBitsGt1,
  const uint8_t      sign,
  int                rightPixel,
  int                belowPixel,
  uint16_t           ricePar,
  bool               isLast,
  const int          maxLog2TrDynamicRange,
  int&               numUsedCtxBins
) const
{
  double currCostSig = 0;
  uint32_t   bestAbsLevel = 0;
  numUsedCtxBins = 0;
  int numBestCtxBin = 0;
  if (!isLast && coeffLevels[0] < 3)
  {
    if (cctx.remRegBins >= 4)
    rd64CodedCostSig = xGetRateSigCoef(*fracBitsSig, 0);
    else
      rd64CodedCostSig = xGetICost(1 << SCALE_BITS);
    rd64CodedCost = rd64CodedCost0 + rd64CodedCostSig;
    if (cctx.remRegBins >= 4)
      numUsedCtxBins++;
    if (coeffLevels[0] == 0)
    {
      return bestAbsLevel;
    }
  }
  else
  {
    rd64CodedCost = MAX_DOUBLE;
  }

  if (!isLast)
  {
    if (cctx.remRegBins >= 4)
      currCostSig = xGetRateSigCoef(*fracBitsSig, 1);
    else
      currCostSig = xGetICost(1 << SCALE_BITS);
    if (coeffLevels[0] >= 3 && cctx.remRegBins >= 4)
      numUsedCtxBins++;
  }

  for (int errorInd = 1; errorInd <= m_testedLevels; errorInd++)
  {
    int absLevel = coeffLevels[errorInd - 1];
    double dErr = 0.0;
    dErr = double(levelDouble - (Intermediate_Int(absLevel) << qBits));
    coeffLevelError[errorInd] = dErr * dErr * errorScale;
    int modAbsLevel = absLevel;
    if (cctx.remRegBins >= 4) 
    {
      modAbsLevel = cctx.deriveModCoeff(rightPixel, belowPixel, absLevel, m_bdpcm);
    }
    int numCtxBins = 0;
    double dCurrCost = coeffLevelError[errorInd] + xGetICost(xGetICRateTS(modAbsLevel, fracBitsPar, cctx, fracBitsAccess, fracBitsSign, fracBitsGt1, numCtxBins, sign, ricePar, maxLog2TrDynamicRange));

    if (cctx.remRegBins >= 4)
      dCurrCost += currCostSig; // if cctx.numCtxBins < 4, xGetICRateTS return rate including sign cost. dont need to add any more

    if (dCurrCost < rd64CodedCost)
    {
      bestAbsLevel = absLevel;
      rd64CodedCost = dCurrCost;
      rd64CodedCostSig = currCostSig;
      numBestCtxBin = numCtxBins;
    }
  }
  numUsedCtxBins += numBestCtxBin;
  return bestAbsLevel;
}

inline int QuantRDOQ::xGetICRateTS( const uint32_t            absLevel,
                                    const BinFracBits&        fracBitsPar,
                                    const CoeffCodingContext& cctx,
                                    const FracBitsAccess&     fracBitsAccess,
                                    const BinFracBits&        fracBitsSign,
                                    const BinFracBits&        fracBitsGt1,
                                    int&                      numCtxBins,
                                    const uint8_t             sign,
                                    const uint16_t            ricePar,
                                    const int                 maxLog2TrDynamicRange  ) const
{
 
  if (cctx.remRegBins < 4) // Full by-pass coding 
  {
    int rate = absLevel ? (1 << SCALE_BITS) : 0; // 1 bit to signal sign of non-zero 

    uint32_t symbol = absLevel;

    uint32_t length;
    const int threshold = COEF_REMAIN_BIN_REDUCTION;
    if (symbol < (threshold << ricePar))
    {
      length = symbol >> ricePar;
      rate += (length + 1 + ricePar) << SCALE_BITS;
    }
    else
    {
      length = ricePar;
      symbol = symbol - (threshold << ricePar);
      while (symbol >= (1 << length))
      {
        symbol -= (1 << (length++));
      }
      rate += (threshold + length + 1 - ricePar + length) << SCALE_BITS;
    }

    return rate;
  }

  else if (cctx.remRegBins >= 4 && cctx.remRegBins < 8) // First pass context coding and all by-pass coding ( Sign flag is not counted here)
  {
    int rate = fracBitsSign.intBits[sign]; // sign bits
    if (absLevel)
      numCtxBins++;

    if (absLevel > 1)
    {
      rate += fracBitsGt1.intBits[1];
      rate += fracBitsPar.intBits[(absLevel - 2) & 1];

      numCtxBins += 2;

      int cutoffVal = 2;

      if (absLevel >= cutoffVal)
      {
        uint32_t symbol = (absLevel - cutoffVal) >> 1;
        uint32_t length;
        const int threshold = COEF_REMAIN_BIN_REDUCTION;
        if (symbol < (threshold << ricePar))
        {
          length = symbol >> ricePar;
          rate += (length + 1 + ricePar) << SCALE_BITS;
        }
        else
        {
          length = ricePar;
          symbol = symbol - (threshold << ricePar);
          while (symbol >= (1 << length))
          {
            symbol -= (1 << (length++));
          }
          rate += (threshold + length + 1 - ricePar + length) << SCALE_BITS;
        }
      }
    }
    else if (absLevel == 1)
    {
      rate += fracBitsGt1.intBits[0];
      numCtxBins++;
    }
    else
    {
      rate = 0;
    }
    return rate;
  }
    
  int rate = fracBitsSign.intBits[sign];

  if (absLevel)
    numCtxBins++;

  if( absLevel > 1 )
  {
    rate += fracBitsGt1.intBits[1];
    rate += fracBitsPar.intBits[( absLevel - 2 ) & 1];
    numCtxBins += 2;

          int cutoffVal = 2;
    const int numGtBins = 4;
    for( int i = 0; i < numGtBins; i++ )
    {
      if( absLevel >= cutoffVal )
      {
        const uint16_t ctxGtX = cctx.greaterXCtxIdAbsTS( cutoffVal>>1 );
        const BinFracBits &fracBitsGtX = fracBitsAccess.getFracBitsArray( ctxGtX );
        unsigned gtX = ( absLevel >= ( cutoffVal + 2 ) );
        rate += fracBitsGtX.intBits[gtX];
        numCtxBins++;
      }
      cutoffVal += 2;
    }

    if( absLevel >= cutoffVal )
    {
      uint32_t symbol = ( absLevel - cutoffVal ) >> 1;
      uint32_t length;
      const int threshold = COEF_REMAIN_BIN_REDUCTION;
      if( symbol < ( threshold << ricePar ) )
      {
        length = symbol >> ricePar;
        rate  += ( length + 1 + ricePar ) << SCALE_BITS;
      }
      else
      {
        length = ricePar;
        symbol = symbol - ( threshold << ricePar );
        while( symbol >= ( 1 << length ) )
        {
          symbol -= ( 1 << ( length++ ) );
        }
        rate += ( threshold + length + 1 - ricePar + length ) << SCALE_BITS;
      }
    }
  }
  else if( absLevel == 1 )
  {
    rate += fracBitsGt1.intBits[0];
    numCtxBins++;
  }
  else
  {
    rate = 0;
  }
  return rate;
}

} // namespace vvenc

//! \}


Coverage Report

Created: 2026-04-01 07:49