ContextModelling.h

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/** \file     ContextModelling.h
 *  \brief    Classes providing probability descriptions and contexts (header)
 */

#ifndef __CONTEXTMODELLING__
#define __CONTEXTMODELLING__

#include "Rom.h"
#include "CommonDef.h"
#include "Contexts.h"
#include "Slice.h"
#include "Unit.h"
#include "UnitPartitioner.h"

#include <bitset>


struct CoeffCodingContext
{
public:
  static const int prefixCtx[8];

  CoeffCodingContext(const TransformUnit &tu, ComponentID component, bool signHide, const BdpcmMode bdpcm);

public:
  void  initSubblock     ( int SubsetId, bool sigGroupFlag = false );
public:
  void  resetSigGroup   ()                      { m_sigCoeffGroupFlag.reset( m_subSetPos ); }
  void  setSigGroup     ()                      { m_sigCoeffGroupFlag.set( m_subSetPos ); }
  bool  noneSigGroup    ()                      { return m_sigCoeffGroupFlag.none(); }
  int   lastSubSet      ()                      { return ( maxNumCoeff() - 1 ) >> log2CGSize(); }
  bool  isLastSubSet    ()                      { return lastSubSet() == m_subSetId; }
  bool  only1stSigGroup ()                      { return m_sigCoeffGroupFlag.count()-m_sigCoeffGroupFlag[lastSubSet()]==0; }
  void  setScanPosLast  ( int       posLast )   { m_scanPosLast = posLast; }
public:
  ComponentID     compID          ()                        const { return m_compID; }
  int             subSetId        ()                        const { return m_subSetId; }
  int             subSetPos       ()                        const { return m_subSetPos; }
  int             cgPosY          ()                        const { return m_subSetPosY; }
  int             cgPosX          ()                        const { return m_subSetPosX; }
  unsigned        width           ()                        const { return m_width; }
  unsigned        height          ()                        const { return m_height; }
  unsigned        log2CGWidth     ()                        const { return m_log2CGWidth; }
  unsigned        log2CGHeight    ()                        const { return m_log2CGHeight; }
  unsigned        log2CGSize      ()                        const { return m_log2CGSize; }
  bool            extPrec         ()                        const { return m_extendedPrecision; }
  int             maxLog2TrDRange ()                        const { return m_maxLog2TrDynamicRange; }
  unsigned        maxNumCoeff     ()                        const { return m_maxNumCoeff; }
  int             scanPosLast     ()                        const { return m_scanPosLast; }
  int             minSubPos       ()                        const { return m_minSubPos; }
  int             maxSubPos       ()                        const { return m_maxSubPos; }
  bool            isLast          ()                        const { return ( ( m_scanPosLast >> m_log2CGSize ) == m_subSetId ); }
  bool            isNotFirst      ()                        const { return ( m_subSetId != 0 ); }
  bool            isSigGroup(int scanPosCG) const { return m_sigCoeffGroupFlag[m_scanCG[scanPosCG].idx]; }
  bool            isSigGroup      ()                        const { return m_sigCoeffGroupFlag[ m_subSetPos ]; }
  bool            signHiding      ()                        const { return m_signHiding; }
  bool hideSign(int posFirst, int posLast) const { return (m_signHiding && (posLast - posFirst >= SBH_THRESHOLD)); }
  unsigned        blockPos(int scanPos) const { return m_scan[scanPos].idx; }
  unsigned        posX(int scanPos) const { return m_scan[scanPos].x; }
  unsigned        posY(int scanPos) const { return m_scan[scanPos].y; }
  unsigned        maxLastPosX     ()                        const { return m_maxLastPosX; }
  unsigned        maxLastPosY     ()                        const { return m_maxLastPosY; }
  unsigned        lastXCtxId      ( unsigned  posLastX  )   const { return m_CtxSetLastX( m_lastOffsetX + ( posLastX >> m_lastShiftX ) ); }
  unsigned        lastYCtxId      ( unsigned  posLastY  )   const { return m_CtxSetLastY( m_lastOffsetY + ( posLastY >> m_lastShiftY ) ); }
  int             numCtxBins      ()                        const { return   m_remainingContextBins;      }
  void            setNumCtxBins   ( int n )                       {          m_remainingContextBins  = n; }
  unsigned        sigGroupCtxId   ( bool ts = false     )   const { return ts ? m_sigGroupCtxIdTS : m_sigGroupCtxId; }
  BdpcmMode       bdpcm() const { return m_bdpcm; }

  void            decimateNumCtxBins(int n) { m_remainingContextBins -= n; }
  void            increaseNumCtxBins(int n) { m_remainingContextBins += n; }

  TCoeff          minCoeff()                                const { return m_minCoeff; }
  TCoeff          maxCoeff()                                const { return m_maxCoeff; }

  unsigned sigCtxIdAbs( int scanPos, const TCoeff* coeff, const int state )
  {
    const uint32_t posY      = m_scan[scanPos].y;
    const uint32_t posX      = m_scan[scanPos].x;
    const TCoeff* pData     = coeff + posX + posY * m_width;
    const int     diag      = posX + posY;
    int           numPos    = 0;
    TCoeff        sumAbs    = 0;
#define UPDATE(x) {TCoeff a=abs(x);sumAbs+=std::min(4+(a&1),a);numPos+=int(!!a);}
    if( posX < m_width-1 )
    {
      UPDATE( pData[1] );
      if( posX < m_width-2 )
      {
        UPDATE( pData[2] );
      }
      if( posY < m_height-1 )
      {
        UPDATE( pData[m_width+1] );
      }
    }
    if( posY < m_height-1 )
    {
      UPDATE( pData[m_width] );
      if( posY < m_height-2 )
      {
        UPDATE( pData[m_width<<1] );
      }
    }
#undef UPDATE


    int ctxOfs = int(std::min<TCoeff>((sumAbs+1)>>1, 3)) + ( diag < 2 ? 4 : 0 );

    if (isLuma(m_chType))
    {
      ctxOfs += diag < 5 ? 4 : 0;
    }

    m_tmplCpDiag = diag;
    m_tmplCpSum1 = sumAbs - numPos;
    return m_sigFlagCtxSet[std::max( 0, state-1 )]( ctxOfs );
  }

  uint8_t ctxOffsetAbs()
  {
    int offset = 0;
    if( m_tmplCpDiag != -1 )
    {
      offset  = int(std::min<TCoeff>( m_tmplCpSum1, 4 )) + 1;
      offset += (!m_tmplCpDiag      ? (isLuma(m_chType) ? 15 : 5)
                 : isLuma(m_chType) ? m_tmplCpDiag < 3 ? 10 : (m_tmplCpDiag < 10 ? 5 : 0)
                                    : 0);
    }
    return uint8_t(offset);
  }

  unsigned parityCtxIdAbs   ( uint8_t offset )  const { return m_parFlagCtxSet   ( offset ); }
  unsigned greater1CtxIdAbs ( uint8_t offset )  const { return m_gtxFlagCtxSet[1]( offset ); }
  unsigned greater2CtxIdAbs ( uint8_t offset )  const { return m_gtxFlagCtxSet[0]( offset ); }
  unsigned templateAbsSum( int scanPos, const TCoeff* coeff, int baseLevel )
  {
    const uint32_t  posY  = m_scan[scanPos].y;
    const uint32_t  posX  = m_scan[scanPos].x;
    const TCoeff*   pData = coeff + posX + posY * m_width;
    TCoeff          sum   = 0;
    if (posX < m_width - 1)
    {
      sum += abs(pData[1]);
      if (posX < m_width - 2)
      {
        sum += abs(pData[2]);
      }
      else
      {
        sum += m_histValue;
      }
      if (posY < m_height - 1)
      {
        sum += abs(pData[m_width + 1]);
      }
      else
      {
        sum += m_histValue;
      }
    }
    else
    {
      sum += 2 * m_histValue;
    }

    if (posY < m_height - 1)
    {
      sum += abs(pData[m_width]);
      if (posY < m_height - 2)
      {
        sum += abs(pData[m_width << 1]);
      }
      else
      {
        sum += m_histValue;
      }
    }
    else
    {
      sum += m_histValue;
    }
    return unsigned(std::max<TCoeff>(std::min<TCoeff>(sum - 5 * baseLevel, 31), 0));
  }

  void updateRiceStat(unsigned &riceStat, TCoeff rem, int remainderFlag)
  {
    if (remainderFlag)
    {
      riceStat = (riceStat + floorLog2((uint32_t)rem) + 2) >> 1;
    }
    else
    {
      riceStat = (riceStat + floorLog2((uint32_t)rem)) >> 1;
    }
  }

  static unsigned templateAbsCompare(TCoeff sum)
  {
    for (int rangeIdx = 0; rangeIdx < g_riceThreshold.size(); rangeIdx++)
    {
      if (sum < g_riceThreshold[rangeIdx])
      {
        return g_riceShift[rangeIdx];
      }
    }

    return g_riceShift[g_riceThreshold.size()];
  }

  unsigned templateAbsSumExt(int scanPos, const TCoeff* coeff, int baseLevel)
  {
    unsigned riceParam;
    const uint32_t  posY = m_scan[scanPos].y;
    const uint32_t  posX = m_scan[scanPos].x;
    const TCoeff*   data = coeff + posX + posY * m_width;
    TCoeff          sum = 0;
    if (posX < m_width - 1)
    {
      sum += abs(data[1]);
      if (posX < m_width - 2)
      {
        sum += abs(data[2]);
      }
      else
      {
        sum += m_histValue;
      }

      if (posY < m_height - 1)
      {
        sum += abs(data[m_width + 1]);
      }
      else
      {
        sum += m_histValue;
      }
    }
    else
    {
      sum += 2 * m_histValue;
    }
    if (posY < m_height - 1)
    {
      sum += abs(data[m_width]);
      if (posY < m_height - 2)
      {
        sum += abs(data[m_width << 1]);
      }
      else
      {
        sum += m_histValue;
      }
    }
    else
    {
      sum += m_histValue;
    }

    const int currentShift = templateAbsCompare(sum);
    sum = sum >> currentShift;
    if (baseLevel == 0)
    {
      riceParam = unsigned(std::min<TCoeff>(sum, 31));
    }
    else
    {
      riceParam = unsigned(std::max<TCoeff>(std::min<TCoeff>(sum - baseLevel, 31), 0));
    }

    riceParam = g_goRiceParsCoeff[riceParam] + currentShift;

    return riceParam;
  }

  unsigned (CoeffCodingContext::*deriveRiceRRC)(int scanPos, const TCoeff* coeff, int baseLevel);

  unsigned deriveRice(int scanPos, const TCoeff* coeff, int baseLevel)
  {
    unsigned sumAbs = templateAbsSum(scanPos, coeff, baseLevel);
    unsigned riceParam = g_goRiceParsCoeff[sumAbs];
    return riceParam;
  }

  unsigned deriveRiceExt(int scanPos, const TCoeff* coeff, int baseLevel)
  {
    unsigned riceParam = templateAbsSumExt(scanPos, coeff, baseLevel);
    return riceParam;
  }

  unsigned sigCtxIdAbsTS( int scanPos, const TCoeff* coeff )
  {
    const uint32_t  posY   = m_scan[scanPos].y;
    const uint32_t  posX   = m_scan[scanPos].x;
    const TCoeff*   posC   = coeff + posX + posY * m_width;
    int             numPos = 0;
#define UPDATE(x) {TCoeff a=abs(x);numPos+=int(!!a);}
    if( posX > 0 )
    {
      UPDATE( posC[-1] );
    }
    if( posY > 0 )
    {
      UPDATE( posC[-(int)m_width] );
    }
#undef UPDATE

    return m_tsSigFlagCtxSet( numPos );
  }

  unsigned parityCtxIdAbsTS   ()                  const { return m_tsParFlagCtxSet(      0 ); }
  unsigned greaterXCtxIdAbsTS ( uint8_t offset )  const { return m_tsGtxFlagCtxSet( offset ); }

  unsigned lrg1CtxIdAbsTS(int scanPos, const TCoeff *coeff, const BdpcmMode bdpcm)
  {
    const uint32_t  posY = m_scan[scanPos].y;
    const uint32_t  posX = m_scan[scanPos].x;
    const TCoeff*   posC = coeff + posX + posY * m_width;

    int             numPos = 0;
#define UPDATE(x) {TCoeff a=abs(x);numPos+=int(!!a);}

    if (bdpcm != BdpcmMode::NONE)
    {
      numPos = 3;
    }
    else
    {
      if (posX > 0)
      {
        UPDATE(posC[-1]);
      }
      if (posY > 0)
      {
        UPDATE(posC[-(int)m_width]);
      }
    }

#undef UPDATE
    return m_tsLrg1FlagCtxSet(numPos);
  }

  unsigned signCtxIdAbsTS(int scanPos, const TCoeff *coeff, const BdpcmMode bdpcm)
  {
    const uint32_t  posY = m_scan[scanPos].y;
    const uint32_t  posX = m_scan[scanPos].x;
    const TCoeff*   pData = coeff + posX + posY * m_width;

    int rightSign = 0, belowSign = 0;
    unsigned signCtx = 0;

    if (posX > 0)
    {
      rightSign = sgn(pData[-1]);
    }
    if (posY > 0)
    {
      belowSign = sgn(pData[-(int)m_width]);
    }

    if ((rightSign == 0 && belowSign == 0) || ((rightSign*belowSign) < 0))
    {
      signCtx = 0;
    }
    else if (rightSign >= 0 && belowSign >= 0)
    {
      signCtx = 1;
    }
    else
    {
      signCtx = 2;
    }
    if (bdpcm != BdpcmMode::NONE)
    {
      signCtx += 3;
    }
    return m_tsSignFlagCtxSet(signCtx);
  }

  void neighTS(int &rightPixel, int &belowPixel, int scanPos, const TCoeff* coeff)
  {
    const uint32_t  posY = m_scan[scanPos].y;
    const uint32_t  posX = m_scan[scanPos].x;
    const TCoeff*   data = coeff + posX + posY * m_width;

    rightPixel = belowPixel = 0;

    if (posX > 0)
    {
      rightPixel = int(data[-1]);
    }
    if (posY > 0)
    {
      belowPixel = int(data[-(int)m_width]);
    }
  }

  int deriveModCoeff(int rightPixel, int belowPixel, TCoeff absCoeff, const bool bdpcm)
  {

    if (absCoeff == 0)
    {
      return 0;
    }
    int pred1, absBelow = abs(belowPixel), absRight = abs(rightPixel);

    int absCoeffMod = int(absCoeff);

    if (!bdpcm)
    {
      pred1 = std::max(absBelow, absRight);

      if (absCoeffMod == pred1)
      {
        absCoeffMod = 1;
      }
      else
      {
        absCoeffMod = absCoeffMod < pred1 ? absCoeffMod + 1 : absCoeffMod;
      }
    }

    return(absCoeffMod);
  }

  TCoeff decDeriveModCoeff(int rightPixel, int belowPixel, TCoeff absCoeff)
  {

    if (absCoeff == 0)
    {
      return 0;
    }

    int pred1, absBelow = abs(belowPixel), absRight = abs(rightPixel);
    pred1 = std::max(absBelow, absRight);

    TCoeff absCoeffMod;

    if (absCoeff == 1 && pred1 > 0)
    {
      absCoeffMod = pred1;
    }
    else
    {
      absCoeffMod = absCoeff - (absCoeff <= pred1);
    }
    return(absCoeffMod);
  }

  unsigned templateAbsSumTS( int scanPos, const TCoeff* coeff )
  {
    return 1;
  }

  int                       regBinLimit;

  unsigned  getBaseLevel()                                   { return m_cctxBaseLevel; };
  void setBaseLevel(int value)                               { m_cctxBaseLevel = value; };
  TCoeff getHistValue()                                      { return m_histValue; };
  void setHistValue(TCoeff value)                            { m_histValue = value; };
  bool getUpdateHist() { return m_updateHist; };
  void setUpdateHist(bool value) { m_updateHist = value; };

private:
  // constant
  const ComponentID         m_compID;
  const ChannelType         m_chType;
  const unsigned            m_width;
  const unsigned            m_height;
  const unsigned            m_log2CGWidth;
  const unsigned            m_log2CGHeight;
  const unsigned            m_log2CGSize;
  const unsigned            m_widthInGroups;
  const unsigned            m_heightInGroups;
  const unsigned            m_log2BlockWidth;
  const unsigned            m_log2BlockHeight;
  const unsigned            m_maxNumCoeff;
  const bool                m_signHiding;
  const bool                m_extendedPrecision;
  const int                 m_maxLog2TrDynamicRange;
  const ScanElement *       m_scan;
  const ScanElement *       m_scanCG;
  const CtxSet              m_CtxSetLastX;
  const CtxSet              m_CtxSetLastY;
  const unsigned            m_maxLastPosX;
  const unsigned            m_maxLastPosY;
  const int                 m_lastOffsetX;
  const int                 m_lastOffsetY;
  const int                 m_lastShiftX;
  const int                 m_lastShiftY;
  const TCoeff              m_minCoeff;
  const TCoeff              m_maxCoeff;
  // modified
  int                       m_scanPosLast;
  int                       m_subSetId;
  int                       m_subSetPos;
  int                       m_subSetPosX;
  int                       m_subSetPosY;
  int                       m_minSubPos;
  int                       m_maxSubPos;
  unsigned                  m_sigGroupCtxId;
  TCoeff                    m_tmplCpSum1;
  int                       m_tmplCpDiag;
  CtxSet                    m_sigFlagCtxSet[3];
  CtxSet                    m_parFlagCtxSet;
  CtxSet                    m_gtxFlagCtxSet[2];
  unsigned                  m_sigGroupCtxIdTS;
  CtxSet                    m_tsSigFlagCtxSet;
  CtxSet                    m_tsParFlagCtxSet;
  CtxSet                    m_tsGtxFlagCtxSet;
  CtxSet                    m_tsLrg1FlagCtxSet;
  CtxSet                    m_tsSignFlagCtxSet;
  int                       m_remainingContextBins;
  std::bitset<MLS_GRP_NUM>  m_sigCoeffGroupFlag;
  const BdpcmMode           m_bdpcm;
  int                       m_cctxBaseLevel;
  TCoeff                    m_histValue;
  bool                      m_updateHist;
};


class CUCtx
{
public:
  CUCtx()              : isDQPCoded(false), isChromaQpAdjCoded(false),
                         qgStart(false)
  {
    violatesLfnstConstrained.fill(false);
    lfnstLastScanPos           = false;
    violatesMtsCoeffConstraint = false;
    mtsLastScanPos             = false;
  }
  CUCtx(int _qp)       : isDQPCoded(false), isChromaQpAdjCoded(false),
                         qgStart(false),
                         qp(_qp)
                         {
                           violatesLfnstConstrained.fill(false);
                           lfnstLastScanPos                              = false;
                           violatesMtsCoeffConstraint                    = false;
                           mtsLastScanPos                                = false;
                         }
  ~CUCtx() {}
public:
  bool      isDQPCoded;
  bool      isChromaQpAdjCoded;
  bool      qgStart;
  bool      lfnstLastScanPos;
  int8_t    qp;                   // used as a previous(last) QP and for QP prediction
  EnumArray<bool, ChannelType> violatesLfnstConstrained;
  bool      violatesMtsCoeffConstraint;
  bool      mtsLastScanPos;
};

namespace DeriveCtx
{
void     CtxSplit     ( const CodingStructure& cs, Partitioner& partitioner, unsigned& ctxSpl, unsigned& ctxQt, unsigned& ctxHv, unsigned& ctxHorBt, unsigned& ctxVerBt, bool* canSplit = nullptr );
unsigned CtxModeConsFlag( const CodingStructure& cs, Partitioner& partitioner );
unsigned CtxQtCbf     ( const ComponentID compID, const bool prevCbf = false, const int ispIdx = 0 );
unsigned CtxInterDir  ( const PredictionUnit& pu );
unsigned CtxSkipFlag  ( const CodingUnit& cu );
unsigned CtxAffineFlag( const CodingUnit& cu );
unsigned CtxPredModeFlag( const CodingUnit& cu );
unsigned CtxIBCFlag(const CodingUnit& cu);
unsigned CtxMipFlag   ( const CodingUnit& cu );
unsigned CtxPltCopyFlag( const unsigned prevRunType, const unsigned dist );
}

#endif // __CONTEXTMODELLING__