CABACWriter.cpp

  // init coeff coding context
  CoeffCodingContext  cctx    ( tu, compID, signHiding );
  const TCoeff*       coeff   = tu.getCoeffs( compID ).buf;

  // determine and set last coeff position and sig group flags
  int                      scanPosLast = -1;
  std::bitset<MLS_GRP_NUM> sigGroupFlags;
  for( int scanPos = 0; scanPos < cctx.maxNumCoeff(); scanPos++)
  {
    unsigned blkPos = cctx.blockPos( scanPos );
    if( coeff[blkPos] )
    {
      scanPosLast = scanPos;
      sigGroupFlags.set( scanPos >> cctx.log2CGSize() );
    }
  }
  CHECK( scanPosLast < 0, "Coefficient coding called for empty TU" );
  cctx.setScanPosLast(scanPosLast);

#if JVET_O0094_LFNST_ZERO_PRIM_COEFFS
  if( cuCtx && tu.mtsIdx != MTS_SKIP && tu.blocks[ compID ].height >= 4 && tu.blocks[ compID ].width >= 4 )
  {
    const int maxLfnstPos = ((tu.blocks[compID].height == 4 && tu.blocks[compID].width == 4) || (tu.blocks[compID].height == 8 && tu.blocks[compID].width == 8)) ? 7 : 15;
    cuCtx->violatesLfnstConstrained[ toChannelType(compID) ] |= cctx.scanPosLast() > maxLfnstPos;
  }
#endif
  // code last coeff position
  last_sig_coeff( cctx, tu, compID );

  // code subblocks
  const int stateTab  = ( tu.cs->slice->getDepQuantEnabledFlag() ? 32040 : 0 );
  int       state     = 0;

#if JVET_O0052_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT
  int ctxBinSampleRatio = (compID == COMPONENT_Y) ? MAX_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT_LUMA : MAX_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT_CHROMA;
  cctx.regBinLimit = (tu.getTbAreaAfterCoefZeroOut(compID) * ctxBinSampleRatio) >> 4;
#endif

  for( int subSetId = ( cctx.scanPosLast() >> cctx.log2CGSize() ); subSetId >= 0; subSetId--)
  {
    cctx.initSubblock       ( subSetId, sigGroupFlags[subSetId] );
    if( ( tu.mtsIdx > MTS_SKIP || ( tu.cu->sbtInfo != 0 && tu.blocks[ compID ].height <= 32 && tu.blocks[ compID ].width <= 32 ) ) && !tu.cu->transQuantBypass && compID == COMPONENT_Y )
    {
      if( ( tu.blocks[ compID ].height == 32 && cctx.cgPosY() >= ( 16 >> cctx.log2CGHeight() ) )
       || ( tu.blocks[ compID ].width  == 32 && cctx.cgPosX() >= ( 16 >> cctx.log2CGWidth()  ) ) )
      {
        continue;
      }
    }
    residual_coding_subblock( cctx, coeff, stateTab, state );

  }


}

void CABACWriter::mts_coding( const TransformUnit& tu, ComponentID compID )
{
#if !JVET_O0294_TRANSFORM_CLEANUP
  const CodingUnit  &cu = *tu.cu;
#endif
  const bool  tsAllowed = TU::isTSAllowed ( tu, compID );
  const bool mtsAllowed = TU::isMTSAllowed( tu, compID );

  if( !mtsAllowed && !tsAllowed ) return;

  int symbol  = 0;
  int ctxIdx  = 0;

  if( tsAllowed )
  {
#if JVET_O0294_TRANSFORM_CLEANUP
    symbol = (tu.mtsIdx == MTS_SKIP) ? 1 : 0;
#else
    symbol = (tu.mtsIdx == MTS_SKIP) ? 0 : 1;
#endif
    ctxIdx = 6;
    m_BinEncoder.encodeBin( symbol, Ctx::MTSIndex( ctxIdx ) );
  }

  if( tu.mtsIdx != MTS_SKIP )
  {
    if( mtsAllowed )
    {
      symbol = tu.mtsIdx != MTS_DCT2_DCT2 ? 1 : 0;
#if JVET_O0294_TRANSFORM_CLEANUP
      ctxIdx = 0;
#else
      ctxIdx = std::min( (int)cu.qtDepth, 5 );
#endif
      m_BinEncoder.encodeBin( symbol, Ctx::MTSIndex( ctxIdx ) );

      if( symbol )
      {
        ctxIdx = 7;
        for( int i = 0; i < 3; i++, ctxIdx++ )
        {
          symbol = tu.mtsIdx > i + MTS_DST7_DST7 ? 1 : 0;
          m_BinEncoder.encodeBin( symbol, Ctx::MTSIndex( ctxIdx ) );

          if( !symbol )
          {
            break;
          }
        }
      }
    }
  }
#if JVET_O0294_TRANSFORM_CLEANUP
  DTRACE( g_trace_ctx, D_SYNTAX, "mts_coding() etype=%d pos=(%d,%d) mtsIdx=%d\n", COMPONENT_Y, tu.cu->lx(), tu.cu->ly(), tu.mtsIdx);
#else
  DTRACE( g_trace_ctx, D_SYNTAX, "mts_coding() etype=%d pos=(%d,%d) mtsIdx=%d\n", COMPONENT_Y, cu.lx(), cu.ly(), tu.mtsIdx );
#endif
}

void CABACWriter::isp_mode( const CodingUnit& cu )
{
  if( !CU::isIntra( cu ) || !isLuma( cu.chType ) || cu.firstPU->multiRefIdx || cu.ipcm || !cu.cs->sps->getUseISP() || cu.bdpcmMode )
  {
    CHECK( cu.ispMode != NOT_INTRA_SUBPARTITIONS, "error: cu.intraSubPartitions != 0" );
    return;
  }
  const ISPType allowedSplits = CU::canUseISPSplit( cu, getFirstComponentOfChannel( cu.chType ) );
  if( allowedSplits == NOT_INTRA_SUBPARTITIONS ) return;

  if( cu.ispMode == NOT_INTRA_SUBPARTITIONS )
  {
    m_BinEncoder.encodeBin( 0, Ctx::ISPMode( 0 ) );
  }
  else
  {
    m_BinEncoder.encodeBin( 1, Ctx::ISPMode( 0 ) );

    if( allowedSplits == CAN_USE_VER_AND_HORL_SPLITS )
    {
      m_BinEncoder.encodeBin( cu.ispMode - 1, Ctx::ISPMode( 1 ) );
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "intra_subPartitions() etype=%d pos=(%d,%d) ispIdx=%d\n", cu.chType, cu.blocks[cu.chType].x, cu.blocks[cu.chType].y, (int)cu.ispMode );
}

void CABACWriter::explicit_rdpcm_mode( const TransformUnit& tu, ComponentID compID )
{
  const CodingUnit& cu = *tu.cu;
  if( !CU::isIntra(cu) && CU::isRDPCMEnabled(cu) && ( tu.mtsIdx==MTS_SKIP || cu.transQuantBypass ) )
  {
    ChannelType chType = toChannelType( compID );
    switch( tu.rdpcm[compID] )
    {
    case RDPCM_VER:
      m_BinEncoder.encodeBin( 1, Ctx::RdpcmFlag(chType) );
      m_BinEncoder.encodeBin( 1, Ctx::RdpcmDir (chType) );
      break;
    case RDPCM_HOR:
      m_BinEncoder.encodeBin( 1, Ctx::RdpcmFlag(chType) );
      m_BinEncoder.encodeBin( 0, Ctx::RdpcmDir (chType) );
      break;
    default: // RDPCM_OFF
      m_BinEncoder.encodeBin( 0, Ctx::RdpcmFlag(chType) );
    }
  }
}

void CABACWriter::residual_lfnst_mode( const CodingUnit& cu, CUCtx& cuCtx )
{
  if( cu.ispMode != NOT_INTRA_SUBPARTITIONS || cu.mipFlag == true ||
    ( CS::isDualITree( *cu.cs ) && cu.chType == CHANNEL_TYPE_CHROMA && std::min( cu.blocks[ 1 ].width, cu.blocks[ 1 ].height ) < 4 ) )
  {
    return;
  }

  if( cu.cs->sps->getUseLFNST() && CU::isIntra( cu ) && !CU::isLosslessCoded( cu ) )
  {
    const bool lumaFlag                   = CS::isDualITree( *cu.cs ) ? (   isLuma( cu.chType ) ? true : false ) : true;
    const bool chromaFlag                 = CS::isDualITree( *cu.cs ) ? ( isChroma( cu.chType ) ? true : false ) : true;
          bool nonZeroCoeffNonTs;
#if JVET_O0094_LFNST_ZERO_PRIM_COEFFS
          bool nonZeroCoeffNonTsCorner8x8 = ( lumaFlag && cuCtx.violatesLfnstConstrained[CHANNEL_TYPE_LUMA] ) || (chromaFlag && cuCtx.violatesLfnstConstrained[CHANNEL_TYPE_CHROMA] );
#else
          bool nonZeroCoeffNonTsCorner8x8 = CU::getNumNonZeroCoeffNonTsCorner8x8( cu, lumaFlag, chromaFlag ) > 0;
#endif
    const int  nonZeroCoeffThr            = CS::isDualITree( *cu.cs ) ? ( isLuma( cu.chType ) ? LFNST_SIG_NZ_LUMA : LFNST_SIG_NZ_CHROMA ) : LFNST_SIG_NZ_LUMA + LFNST_SIG_NZ_CHROMA;
    cuCtx.numNonZeroCoeffNonTs            = CU::getNumNonZeroCoeffNonTs( cu, lumaFlag, chromaFlag );
    nonZeroCoeffNonTs                     = cuCtx.numNonZeroCoeffNonTs > nonZeroCoeffThr;
#if JVET_O0368_LFNST_WITH_DCT2_ONLY
    const bool isNonDCT2 = (TU::getCbf(*cu.firstTU, ComponentID(COMPONENT_Y)) && cu.firstTU->mtsIdx != MTS_DCT2_DCT2);
    if (!nonZeroCoeffNonTs || nonZeroCoeffNonTsCorner8x8 || isNonDCT2 )
#else
    if( !nonZeroCoeffNonTs || nonZeroCoeffNonTsCorner8x8 )
#endif
    {
      return;
    }
  }
  else
  {
    return;
  }


  unsigned cctx = 0;
#if JVET_O0368_LFNST_WITH_DCT2_ONLY
  if ( CS::isDualITree(*cu.cs) ) cctx++;
#else
  if( cu.firstTU->mtsIdx < MTS_DST7_DST7 && CS::isDualITree( *cu.cs ) ) cctx++;
#endif

  const uint32_t idxLFNST = cu.lfnstIdx;
  assert( idxLFNST < 3 );
  m_BinEncoder.encodeBin( idxLFNST ? 1 : 0, Ctx::LFNSTIdx( cctx ) );

  if( idxLFNST )
  {
    m_BinEncoder.encodeBinEP( ( idxLFNST - 1 ) ? 1 : 0 );
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "residual_lfnst_mode() etype=%d pos=(%d,%d) mode=%d\n", COMPONENT_Y, cu.lx(), cu.ly(), ( int ) cu.lfnstIdx );
}

void CABACWriter::last_sig_coeff( CoeffCodingContext& cctx, const TransformUnit& tu, ComponentID compID )
{
  unsigned blkPos = cctx.blockPos( cctx.scanPosLast() );
  unsigned posX, posY;
  {
    posY  = blkPos / cctx.width();
    posX  = blkPos - ( posY * cctx.width() );
  }

  unsigned CtxLast;
  unsigned GroupIdxX = g_uiGroupIdx[ posX ];
  unsigned GroupIdxY = g_uiGroupIdx[ posY ];

  unsigned maxLastPosX = cctx.maxLastPosX();
  unsigned maxLastPosY = cctx.maxLastPosY();

  if( ( tu.mtsIdx > MTS_SKIP || ( tu.cu->sbtInfo != 0 && tu.blocks[ compID ].width <= 32 && tu.blocks[ compID ].height <= 32 ) ) && !tu.cu->transQuantBypass && compID == COMPONENT_Y )
  {
    maxLastPosX = ( tu.blocks[compID].width  == 32 ) ? g_uiGroupIdx[ 15 ] : maxLastPosX;
    maxLastPosY = ( tu.blocks[compID].height == 32 ) ? g_uiGroupIdx[ 15 ] : maxLastPosY;
  }

  for( CtxLast = 0; CtxLast < GroupIdxX; CtxLast++ )
  {
    m_BinEncoder.encodeBin( 1, cctx.lastXCtxId( CtxLast ) );
  }
  if( GroupIdxX < maxLastPosX )
  {
    m_BinEncoder.encodeBin( 0, cctx.lastXCtxId( CtxLast ) );
  }
  for( CtxLast = 0; CtxLast < GroupIdxY; CtxLast++ )
  {
    m_BinEncoder.encodeBin( 1, cctx.lastYCtxId( CtxLast ) );
  }
  if( GroupIdxY < maxLastPosY )
  {
    m_BinEncoder.encodeBin( 0, cctx.lastYCtxId( CtxLast ) );
  }
  if( GroupIdxX > 3 )
  {
    posX -= g_uiMinInGroup[ GroupIdxX ];
    for (int i = ( ( GroupIdxX - 2 ) >> 1 ) - 1 ; i >= 0; i-- )
    {
      m_BinEncoder.encodeBinEP( ( posX >> i ) & 1 );
    }
  }
  if( GroupIdxY > 3 )
  {
    posY -= g_uiMinInGroup[ GroupIdxY ];
    for ( int i = ( ( GroupIdxY - 2 ) >> 1 ) - 1 ; i >= 0; i-- )
    {
      m_BinEncoder.encodeBinEP( ( posY >> i ) & 1 );
    }
  }
}



void CABACWriter::residual_coding_subblock( CoeffCodingContext& cctx, const TCoeff* coeff, const int stateTransTable, int& state )
{
  //===== init =====
  const int   minSubPos   = cctx.minSubPos();
  const bool  isLast      = cctx.isLast();
  int         firstSigPos = ( isLast ? cctx.scanPosLast() : cctx.maxSubPos() );
  int         nextSigPos  = firstSigPos;

  //===== encode significant_coeffgroup_flag =====
  if( !isLast && cctx.isNotFirst() )
  {
    if( cctx.isSigGroup() )
    {
      m_BinEncoder.encodeBin( 1, cctx.sigGroupCtxId() );
    }
    else
    {
      m_BinEncoder.encodeBin( 0, cctx.sigGroupCtxId() );
      return;
    }
  }

  uint8_t   ctxOffset[16];

  //===== encode absolute values =====
  const int inferSigPos   = nextSigPos != cctx.scanPosLast() ? ( cctx.isNotFirst() ? minSubPos : -1 ) : nextSigPos;
  int       firstNZPos    = nextSigPos;
  int       lastNZPos     = -1;
  int       remAbsLevel   = -1;
  int       numNonZero    =  0;
  unsigned  signPattern   =  0;
#if JVET_O0052_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT
  int       remRegBins    = cctx.regBinLimit;
#else
  bool      is2x2subblock = ( cctx.log2CGSize() == 2 );
  int       remRegBins    = ( is2x2subblock ? MAX_NUM_REG_BINS_2x2SUBBLOCK : MAX_NUM_REG_BINS_4x4SUBBLOCK );
#endif
  int       firstPosMode2 = minSubPos - 1;

  for( ; nextSigPos >= minSubPos && remRegBins >= 4; nextSigPos-- )
  {
    TCoeff    Coeff      = coeff[ cctx.blockPos( nextSigPos ) ];
    unsigned  sigFlag    = ( Coeff != 0 );
    if( numNonZero || nextSigPos != inferSigPos )
    {
      const unsigned sigCtxId = cctx.sigCtxIdAbs( nextSigPos, coeff, state );
      m_BinEncoder.encodeBin( sigFlag, sigCtxId );
      DTRACE( g_trace_ctx, D_SYNTAX_RESI, "sig_bin() bin=%d ctx=%d\n", sigFlag, sigCtxId );
      remRegBins--;
    }
    else if( nextSigPos != cctx.scanPosLast() )
    {
      cctx.sigCtxIdAbs( nextSigPos, coeff, state ); // required for setting variables that are needed for gtx/par context selection
    }

    if( sigFlag )
    {
      uint8_t&  ctxOff  = ctxOffset[ nextSigPos - minSubPos ];
      ctxOff            = cctx.ctxOffsetAbs();
      numNonZero++;
      firstNZPos  = nextSigPos;
      lastNZPos   = std::max<int>( lastNZPos, nextSigPos );
      remAbsLevel = abs( Coeff ) - 1;

      if( nextSigPos != cctx.scanPosLast() ) signPattern <<= 1;
      if( Coeff < 0 )                        signPattern++;

      unsigned gt1 = !!remAbsLevel;
      m_BinEncoder.encodeBin( gt1, cctx.greater1CtxIdAbs(ctxOff) );
      DTRACE( g_trace_ctx, D_SYNTAX_RESI, "gt1_flag() bin=%d ctx=%d\n", gt1, cctx.greater1CtxIdAbs(ctxOff) );
      remRegBins--;

      if( gt1 )
      {
        remAbsLevel  -= 1;
        m_BinEncoder.encodeBin( remAbsLevel&1, cctx.parityCtxIdAbs( ctxOff ) );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "par_flag() bin=%d ctx=%d\n", remAbsLevel&1, cctx.parityCtxIdAbs( ctxOff ) );
        remAbsLevel >>= 1;

        remRegBins--;
        unsigned gt2 = !!remAbsLevel;
        m_BinEncoder.encodeBin(gt2, cctx.greater2CtxIdAbs(ctxOff));
        DTRACE(g_trace_ctx, D_SYNTAX_RESI, "gt2_flag() bin=%d ctx=%d\n", gt2, cctx.greater2CtxIdAbs(ctxOff));
        remRegBins--;
      }
    }

    state = ( stateTransTable >> ((state<<2)+((Coeff&1)<<1)) ) & 3;
  }
  firstPosMode2 = nextSigPos;
#if JVET_O0052_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT
  cctx.regBinLimit = remRegBins;
#endif


  //===== 2nd PASS: Go-rice codes =====
  unsigned ricePar = 0;
  for( int scanPos = firstSigPos; scanPos > firstPosMode2; scanPos-- )
  {
    int       sumAll = cctx.templateAbsSum(scanPos, coeff, 4);
    ricePar = g_auiGoRiceParsCoeff[sumAll];
    unsigned absLevel = abs( coeff[ cctx.blockPos( scanPos ) ] );
    if( absLevel >= 4 )
    {
      unsigned rem      = ( absLevel - 4 ) >> 1;
      m_BinEncoder.encodeRemAbsEP( rem, ricePar, cctx.extPrec(), cctx.maxLog2TrDRange() );
      DTRACE( g_trace_ctx, D_SYNTAX_RESI, "rem_val() bin=%d ctx=%d\n", rem, ricePar );
    }
  }

  //===== coeff bypass ====
  for( int scanPos = firstPosMode2; scanPos >= minSubPos; scanPos-- )
  {
    TCoeff    Coeff     = coeff[ cctx.blockPos( scanPos ) ];
    unsigned  absLevel  = abs( Coeff );
    int       sumAll = cctx.templateAbsSum(scanPos, coeff, 0);
    int       rice      = g_auiGoRiceParsCoeff                        [sumAll];
    int       pos0      = g_auiGoRicePosCoeff0[std::max(0, state - 1)][sumAll];
    unsigned  rem       = ( absLevel == 0 ? pos0 : absLevel <= pos0 ? absLevel-1 : absLevel );
    m_BinEncoder.encodeRemAbsEP( rem, rice, cctx.extPrec(), cctx.maxLog2TrDRange() );
    DTRACE( g_trace_ctx, D_SYNTAX_RESI, "rem_val() bin=%d ctx=%d\n", rem, rice );
    state = ( stateTransTable >> ((state<<2)+((absLevel&1)<<1)) ) & 3;
    if( absLevel )
    {
      numNonZero++;
      lastNZPos   = std::max<int>( lastNZPos, scanPos );
      signPattern <<= 1;
      if( Coeff < 0 ) signPattern++;
    }
  }

  //===== encode sign's =====
  unsigned numSigns = numNonZero;
  if( cctx.hideSign( firstNZPos, lastNZPos ) )
  {
    numSigns    --;
    signPattern >>= 1;
  }
  m_BinEncoder.encodeBinsEP( signPattern, numSigns );
}

void CABACWriter::residual_codingTS( const TransformUnit& tu, ComponentID compID )
{
  DTRACE( g_trace_ctx, D_SYNTAX, "residual_codingTS() etype=%d pos=(%d,%d) size=%dx%d\n", tu.blocks[compID].compID, tu.blocks[compID].x, tu.blocks[compID].y, tu.blocks[compID].width, tu.blocks[compID].height );

  // init coeff coding context
  CoeffCodingContext  cctx    ( tu, compID, false, tu.cu->bdpcmMode );
  const TCoeff*       coeff   = tu.getCoeffs( compID ).buf;

  cctx.setNumCtxBins( 2 * tu.lwidth()*tu.lheight() );

  // determine and set last coeff position and sig group flags
  std::bitset<MLS_GRP_NUM> sigGroupFlags;
  for( int scanPos = 0; scanPos < cctx.maxNumCoeff(); scanPos++)
  {
    unsigned blkPos = cctx.blockPos( scanPos );
    if( coeff[blkPos] )
    {
      sigGroupFlags.set( scanPos >> cctx.log2CGSize() );
    }
  }

  // code subblocks
  for( int subSetId = 0; subSetId <= ( cctx.maxNumCoeff() - 1 ) >> cctx.log2CGSize(); subSetId++ )
  {
    cctx.initSubblock         ( subSetId, sigGroupFlags[subSetId] );
    residual_coding_subblockTS( cctx, coeff );
  }
}

void CABACWriter::residual_coding_subblockTS( CoeffCodingContext& cctx, const TCoeff* coeff )
{
  //===== init =====
  const int   minSubPos   = cctx.maxSubPos();
  int         firstSigPos = cctx.minSubPos();
  int         nextSigPos  = firstSigPos;

  //===== encode significant_coeffgroup_flag =====
  if( !cctx.isLastSubSet() || !cctx.only1stSigGroup() )
  {
    if( cctx.isSigGroup() )
    {
      if( cctx.isContextCoded() )
      {
        m_BinEncoder.encodeBin( 1, cctx.sigGroupCtxId( true ) );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sigGroup() bin=%d ctx=%d\n", 1, cctx.sigGroupCtxId() );
      }
      else
      {
        m_BinEncoder.encodeBinEP( 1 );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sigGroup() EPbin=%d\n", 1 );
      }
    }
    else
    {
      if( cctx.isContextCoded() )
      {
        m_BinEncoder.encodeBin( 0, cctx.sigGroupCtxId( true ) );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sigGroup() bin=%d ctx=%d\n", 0, cctx.sigGroupCtxId() );
      }
      else
      {
        m_BinEncoder.encodeBinEP( 0 );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sigGroup() EPbin=%d\n", 0 );
      }
      return;
    }
  }

  //===== encode absolute values =====
  const int inferSigPos   = minSubPos;
  int       remAbsLevel   = -1;
  int       numNonZero    =  0;

#if JVET_O0122_TS_SIGN_LEVEL
  int rightPixel, belowPixel, modAbsCoeff;
#endif

  for( ; nextSigPos <= minSubPos; nextSigPos++ )
  {
    TCoeff    Coeff      = coeff[ cctx.blockPos( nextSigPos ) ];
    unsigned  sigFlag    = ( Coeff != 0 );
    if( numNonZero || nextSigPos != inferSigPos )
    {
      if( cctx.isContextCoded() )
      {
        const unsigned sigCtxId = cctx.sigCtxIdAbsTS( nextSigPos, coeff );
        m_BinEncoder.encodeBin( sigFlag, sigCtxId );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sig_bin() bin=%d ctx=%d\n", sigFlag, sigCtxId );
      }
      else
      {
        m_BinEncoder.encodeBinEP( sigFlag );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sig_bin() EPbin=%d\n", sigFlag );
      }
    }

    if( sigFlag )
    {
      //===== encode sign's =====
      int sign = Coeff < 0;
      if( cctx.isContextCoded() )
      {
#if JVET_O0122_TS_SIGN_LEVEL
        const unsigned signCtxId = cctx.signCtxIdAbsTS(nextSigPos, coeff, cctx.bdpcm());
        m_BinEncoder.encodeBin(sign, signCtxId);
#else
        m_BinEncoder.encodeBin( sign, Ctx::TsResidualSign( cctx.bdpcm() ? 1 : 0 ) );
#endif
      }
      else
      {
        m_BinEncoder.encodeBinEP( sign );
      }
      numNonZero++;
#if JVET_O0122_TS_SIGN_LEVEL
      cctx.neighTS(rightPixel, belowPixel, nextSigPos, coeff);
      modAbsCoeff = cctx.deriveModCoeff(rightPixel, belowPixel, abs(Coeff), cctx.bdpcm());
      remAbsLevel = modAbsCoeff - 1;
#else
      remAbsLevel = abs( Coeff ) - 1;
#endif

      unsigned gt1 = !!remAbsLevel;
#if JVET_O0122_TS_SIGN_LEVEL
      const unsigned gt1CtxId = cctx.lrg1CtxIdAbsTS(nextSigPos, coeff, cctx.bdpcm());
      if (cctx.isContextCoded())
      {
        m_BinEncoder.encodeBin(gt1, gt1CtxId);
        DTRACE(g_trace_ctx, D_SYNTAX_RESI, "ts_gt1_flag() bin=%d ctx=%d\n", gt1, gt1CtxId);
      }
      else
      {
        m_BinEncoder.encodeBinEP(gt1);
        DTRACE(g_trace_ctx, D_SYNTAX_RESI, "ts_gt1_flag() EPbin=%d\n", gt1);
      }
#else
      if( cctx.isContextCoded() )
      {
        m_BinEncoder.encodeBin( gt1, cctx.greaterXCtxIdAbsTS(0) );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_gt1_flag() bin=%d ctx=%d\n", gt1, cctx.greaterXCtxIdAbsTS(0) );
      }
      else
      {
        m_BinEncoder.encodeBinEP( gt1 );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_gt1_flag() EPbin=%d\n", gt1 );
      }
#endif

      if( gt1 )
      {
        remAbsLevel  -= 1;
        if( cctx.isContextCoded() )
        {
          m_BinEncoder.encodeBin( remAbsLevel&1, cctx.parityCtxIdAbsTS() );
          DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_par_flag() bin=%d ctx=%d\n", remAbsLevel&1, cctx.parityCtxIdAbsTS() );
        }
        else
        {
          m_BinEncoder.encodeBinEP( remAbsLevel&1 );
          DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_par_flag() EPbin=%d\n", remAbsLevel&1 );
        }
      }
    }
  }

  int cutoffVal = 2;
  int numGtBins = 4;

#if JVET_O0619_GTX_SINGLE_PASS_TS_RESIDUAL_CODING
  for (int scanPos = firstSigPos; scanPos <= minSubPos; scanPos++)
  {
#if JVET_O0122_TS_SIGN_LEVEL
    unsigned absLevel;
    cctx.neighTS(rightPixel, belowPixel, scanPos, coeff);
    absLevel = cctx.deriveModCoeff(rightPixel, belowPixel, abs(coeff[cctx.blockPos(scanPos)]), cctx.bdpcm()); 
#else
    unsigned absLevel = abs(coeff[cctx.blockPos(scanPos)]);
#endif
    cutoffVal = 2;
    for (int i = 0; i < numGtBins; i++)
    {
      if (absLevel >= cutoffVal)
      {
        unsigned gt2 = (absLevel >= (cutoffVal + 2));
        if (cctx.isContextCoded())
        {
          m_BinEncoder.encodeBin(gt2, cctx.greaterXCtxIdAbsTS(cutoffVal >> 1));
          DTRACE(g_trace_ctx, D_SYNTAX_RESI, "ts_gt%d_flag() bin=%d ctx=%d sp=%d coeff=%d\n", i, gt2, cctx.greaterXCtxIdAbsTS(cutoffVal >> 1), scanPos, min<int>(absLevel, cutoffVal + 2));
        }
        else
        {
          m_BinEncoder.encodeBinEP(gt2);
          DTRACE(g_trace_ctx, D_SYNTAX_RESI, "ts_gt%d_flag() EPbin=%d sp=%d coeff=%d\n", i, gt2, scanPos, min<int>(absLevel, cutoffVal + 2));
        }
      }
      cutoffVal += 2;
    }
  }
#else
  for( int i = 0; i < numGtBins; i++ )
  {
    for( int scanPos = firstSigPos; scanPos <= minSubPos; scanPos++ )
    {
#if JVET_O0122_TS_SIGN_LEVEL
      unsigned absLevel;
      cctx.neighTS(rightPixel, belowPixel, scanPos, coeff);
      absLevel = cctx.deriveModCoeff(rightPixel, belowPixel, abs(coeff[cctx.blockPos(scanPos)]), cctx.bdpcm()); 
#else
      unsigned absLevel = abs( coeff[cctx.blockPos( scanPos )] );
#endif
      if( absLevel >= cutoffVal )
      {
        unsigned gt2 = ( absLevel >= ( cutoffVal + 2 ) );
        if( cctx.isContextCoded() )
        {
          m_BinEncoder.encodeBin( gt2, cctx.greaterXCtxIdAbsTS( cutoffVal>>1 ) );
          DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_gt%d_flag() bin=%d ctx=%d sp=%d coeff=%d\n", i, gt2, cctx.greaterXCtxIdAbsTS( cutoffVal>>1 ), scanPos, min<int>( absLevel, cutoffVal+2 ) );
        }
        else
        {
          m_BinEncoder.encodeBinEP( gt2 );
          DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_gt%d_flag() EPbin=%d sp=%d coeff=%d\n", i, gt2, scanPos, min<int>( absLevel, cutoffVal+2 ) );
        }
      }
    }
    cutoffVal += 2;
  }
#endif

  //===== coeff bypass ====
  for( int scanPos = firstSigPos; scanPos <= minSubPos; scanPos++ )
  {
#if JVET_O0122_TS_SIGN_LEVEL
    unsigned absLevel;
    cctx.neighTS(rightPixel, belowPixel, scanPos, coeff);
    absLevel = cctx.deriveModCoeff(rightPixel, belowPixel, abs(coeff[cctx.blockPos(scanPos)]), cctx.bdpcm());
#else
    TCoeff    Coeff     = coeff[ cctx.blockPos( scanPos ) ];
    unsigned  absLevel  = abs( Coeff );
#endif
    if( absLevel >= cutoffVal )
    {
      int       rice = cctx.templateAbsSumTS( scanPos, coeff );
      unsigned  rem  = ( absLevel - cutoffVal ) >> 1;
      m_BinEncoder.encodeRemAbsEP( rem, rice, cctx.extPrec(), cctx.maxLog2TrDRange() );
      DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_rem_val() bin=%d ctx=%d sp=%d\n", rem, rice, scanPos );
    }
  }
}





//================================================================================
//  clause 7.3.8.12
//--------------------------------------------------------------------------------
//    void  cross_comp_pred( tu, compID )
//================================================================================

void CABACWriter::cross_comp_pred( const TransformUnit& tu, ComponentID compID )
{
  CHECK(!( !isLuma( compID ) ), "Unspecified error");
  signed char alpha   = tu.compAlpha[compID];
  unsigned    ctxBase = ( compID == COMPONENT_Cr ? 5 : 0 );
  if( alpha == 0 )
  {
    m_BinEncoder.encodeBin( 0, Ctx::CrossCompPred( ctxBase ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "cross_comp_pred() etype=%d pos=(%d,%d) alpha=%d\n", compID, tu.blocks[compID].x, tu.blocks[compID].y, tu.compAlpha[compID] );
    return;
  }

  static const unsigned log2AbsAlphaMinus1Table[8] = { 0, 1, 1, 2, 2, 2, 3, 3 };
  unsigned sign = ( alpha < 0 );
  if( sign )
  {
    alpha = -alpha;
  }
  CHECK(!( alpha <= 8 ), "Unspecified error");
  m_BinEncoder.encodeBin( 1, Ctx::CrossCompPred(ctxBase) );
  if( alpha > 1)
  {
     m_BinEncoder.encodeBin( 1, Ctx::CrossCompPred(ctxBase+1) );
     unary_max_symbol( log2AbsAlphaMinus1Table[alpha-1]-1, Ctx::CrossCompPred(ctxBase+2), Ctx::CrossCompPred(ctxBase+3), 2 );
  }
  else
  {
     m_BinEncoder.encodeBin( 0, Ctx::CrossCompPred(ctxBase+1) );
  }
  m_BinEncoder.encodeBin( sign, Ctx::CrossCompPred(ctxBase+4) );

  DTRACE( g_trace_ctx, D_SYNTAX, "cross_comp_pred() etype=%d pos=(%d,%d) alpha=%d\n", compID, tu.blocks[compID].x, tu.blocks[compID].y, tu.compAlpha[compID] );
}




//================================================================================
//  helper functions
//--------------------------------------------------------------------------------
//    void  unary_max_symbol  ( symbol, ctxId0, ctxIdN, maxSymbol )
//    void  unary_max_eqprob  ( symbol,                 maxSymbol )
//    void  exp_golomb_eqprob ( symbol, count )
//================================================================================

void CABACWriter::unary_max_symbol( unsigned symbol, unsigned ctxId0, unsigned ctxIdN, unsigned maxSymbol )
{
  CHECK( symbol > maxSymbol, "symbol > maxSymbol" );
  const unsigned totalBinsToWrite = std::min( symbol + 1, maxSymbol );
  for( unsigned binsWritten = 0; binsWritten < totalBinsToWrite; ++binsWritten )
  {
    const unsigned nextBin = symbol > binsWritten;
    m_BinEncoder.encodeBin( nextBin, binsWritten == 0 ? ctxId0 : ctxIdN );
  }
}


void CABACWriter::unary_max_eqprob( unsigned symbol, unsigned maxSymbol )
{
  if( maxSymbol == 0 )
  {
    return;
  }
  bool     codeLast = ( maxSymbol > symbol );
  unsigned bins     = 0;
  unsigned numBins  = 0;
  while( symbol-- )
  {
    bins   <<= 1;
    bins   ++;
    numBins++;
  }
  if( codeLast )
  {
    bins  <<= 1;
    numBins++;
  }
  CHECK(!( numBins <= 32 ), "Unspecified error");
  m_BinEncoder.encodeBinsEP( bins, numBins );
}


void CABACWriter::exp_golomb_eqprob( unsigned symbol, unsigned count )
{
  unsigned bins    = 0;
  unsigned numBins = 0;
  while( symbol >= (unsigned)(1<<count) )
  {
    bins <<= 1;
    bins++;
    numBins++;
    symbol -= 1 << count;
    count++;
  }
  bins <<= 1;
  numBins++;
  bins = (bins << count) | symbol;
  numBins += count;
  CHECK(!( numBins <= 32 ), "Unspecified error");
  m_BinEncoder.encodeBinsEP( bins, numBins );
}

void CABACWriter::codeAlfCtuEnableFlags( CodingStructure& cs, ChannelType channel, AlfSliceParam* alfParam)
{
  if( isLuma( channel ) )
  {
    if (alfParam->enabledFlag[COMPONENT_Y])
      codeAlfCtuEnableFlags( cs, COMPONENT_Y, alfParam );
  }
  else
  {
    if (alfParam->enabledFlag[COMPONENT_Cb])
      codeAlfCtuEnableFlags( cs, COMPONENT_Cb, alfParam );
    if (alfParam->enabledFlag[COMPONENT_Cr])
      codeAlfCtuEnableFlags( cs, COMPONENT_Cr, alfParam );
  }
}
void CABACWriter::codeAlfCtuEnableFlags( CodingStructure& cs, ComponentID compID, AlfSliceParam* alfParam)
{
  uint32_t numCTUs = cs.pcv->sizeInCtus;

  for( int ctuIdx = 0; ctuIdx < numCTUs; ctuIdx++ )
  {
    codeAlfCtuEnableFlag( cs, ctuIdx, compID, alfParam );
  }
}

void CABACWriter::codeAlfCtuEnableFlag( CodingStructure& cs, uint32_t ctuRsAddr, const int compIdx, AlfSliceParam* alfParam)
{
  const bool alfComponentEnabled = (alfParam != NULL) ? alfParam->enabledFlag[compIdx] : cs.slice->getTileGroupAlfEnabledFlag((ComponentID)compIdx);

  if( cs.sps->getALFEnabledFlag() && alfComponentEnabled )
  {
    const PreCalcValues& pcv = *cs.pcv;
    int                 frame_width_in_ctus = pcv.widthInCtus;
    int                 ry = ctuRsAddr / frame_width_in_ctus;
    int                 rx = ctuRsAddr - ry * frame_width_in_ctus;
    const Position      pos( rx * cs.pcv->maxCUWidth, ry * cs.pcv->maxCUHeight );
    const uint32_t          curSliceIdx = cs.slice->getIndependentSliceIdx();
    const uint32_t      curTileIdx = cs.picture->brickMap->getBrickIdxRsMap( pos );
    bool                leftAvail = cs.getCURestricted( pos.offset( -(int)pcv.maxCUWidth, 0 ), pos, curSliceIdx, curTileIdx, CH_L ) ? true : false;
    bool                aboveAvail = cs.getCURestricted( pos.offset( 0, -(int)pcv.maxCUHeight ), pos, curSliceIdx, curTileIdx, CH_L ) ? true : false;

    int leftCTUAddr = leftAvail ? ctuRsAddr - 1 : -1;
    int aboveCTUAddr = aboveAvail ? ctuRsAddr - frame_width_in_ctus : -1;

    uint8_t* ctbAlfFlag = cs.slice->getPic()->getAlfCtuEnableFlag( compIdx );
    int ctx = 0;
    ctx += leftCTUAddr > -1 ? ( ctbAlfFlag[leftCTUAddr] ? 1 : 0 ) : 0;
    ctx += aboveCTUAddr > -1 ? ( ctbAlfFlag[aboveCTUAddr] ? 1 : 0 ) : 0;
    m_BinEncoder.encodeBin( ctbAlfFlag[ctuRsAddr], Ctx::ctbAlfFlag( compIdx * 3 + ctx ) );
  }
}

void CABACWriter::code_unary_fixed( unsigned symbol, unsigned ctxId, unsigned unary_max, unsigned fixed )
{
  bool unary = (symbol <= unary_max);
  m_BinEncoder.encodeBin( unary, ctxId );
  if( unary )
  {
    unary_max_eqprob( symbol, unary_max );
  }
  else
  {
    m_BinEncoder.encodeBinsEP( symbol - unary_max - 1, fixed );
  }
}

void CABACWriter::mip_flag( const CodingUnit& cu )
{
  if( !cu.Y().valid() )
  {
    return;
  }
  if( !cu.cs->sps->getUseMIP() )
  {
    return;
  }
  if( cu.lwidth() > MIP_MAX_WIDTH || cu.lheight() > MIP_MAX_HEIGHT )
  {
    return;
  }
  if( !mipModesAvailable( cu.Y() ) )
  {
    return;
  }

  unsigned ctxId = DeriveCtx::CtxMipFlag( cu );
  m_BinEncoder.encodeBin( cu.mipFlag, Ctx::MipFlag( ctxId ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "mip_flag() pos=(%d,%d) mode=%d\n", cu.lumaPos().x, cu.lumaPos().y, cu.mipFlag ? 1 : 0 );
}

void CABACWriter::mip_pred_modes( const CodingUnit& cu )
{
  if( !cu.Y().valid() )
  {
    return;
  }
  for( const auto &pu : CU::traversePUs( cu ) )
  {
    mip_pred_mode( pu );
  }
}

void CABACWriter::mip_pred_mode( const PredictionUnit& pu )
{
  const int numModes = getNumModesMip( pu.Y() ); CHECKD( numModes > MAX_NUM_MIP_MODE, "Error: too many MIP modes" );

  // derive modeIdx from true MIP mode
  unsigned mpm[NUM_MPM_MIP];
  PU::getMipMPMs(pu, mpm);

  unsigned mipMode = pu.intraDir[CHANNEL_TYPE_LUMA];
  unsigned mpmIdx   = NUM_MPM_MIP;
  for( auto k = 0; k < NUM_MPM_MIP; k++ )
  {
    if( mipMode == mpm[k] )
    {
      mpmIdx = k;
      break;
    }
  }

  unsigned modeIdx;
  if (mpmIdx < NUM_MPM_MIP)
  {
    modeIdx = mpmIdx;
  }
  else
  {
    std::sort( mpm, mpm + NUM_MPM_MIP);

    modeIdx = mipMode;
    for( auto k = (NUM_MPM_MIP - 1); k >= 0; k-- )
    {
      if( modeIdx > mpm[k] )
      {
        modeIdx--;
      }
    }
    CHECK( modeIdx >= (1<<getNumEpBinsMip( pu.Y() )), "Incorrect mode" );
    modeIdx += NUM_MPM_MIP;
  }

  CHECK( modeIdx >= numModes, "modeIdx out of range" );
  int unaryMax = NUM_MPM_MIP - 1;
  int fixedLength = getNumEpBinsMip( pu.Y() );
  code_unary_fixed( modeIdx, Ctx::MipMode( 0 ), unaryMax, fixedLength );

  DTRACE( g_trace_ctx, D_SYNTAX, "mip_pred_mode() pos=(%d,%d) mode=%d\n", pu.lumaPos().x, pu.lumaPos().y, pu.intraDir[CHANNEL_TYPE_LUMA] );
}

void CABACWriter::codeAlfCtuFilterIndex(CodingStructure& cs, uint32_t ctuRsAddr, bool alfEnableLuma)
{
  if ( (!cs.sps->getALFEnabledFlag()) || (!alfEnableLuma))
  {
    return;
  }

  uint8_t* ctbAlfFlag = cs.slice->getPic()->getAlfCtuEnableFlag(COMPONENT_Y);
  if (!ctbAlfFlag[ctuRsAddr])
  {
    return;
  }

  short* alfCtbFilterIndex = cs.slice->getPic()->getAlfCtbFilterIndex();
  const unsigned filterSetIdx = alfCtbFilterIndex[ctuRsAddr];
  unsigned numAps = cs.slice->getTileGroupNumAps();
  unsigned numAvailableFiltSets = numAps + NUM_FIXED_FILTER_SETS;
  if (numAvailableFiltSets > NUM_FIXED_FILTER_SETS)
  {
    int useLatestFilt = (filterSetIdx == NUM_FIXED_FILTER_SETS) ? 1 : 0;
    m_BinEncoder.encodeBin(useLatestFilt, Ctx::AlfUseLatestFilt());
    if (!useLatestFilt)
    {

      if (numAps == 1)
      {
        CHECK(filterSetIdx >= NUM_FIXED_FILTER_SETS, "fixed set numavail < num_fixed");
        xWriteTruncBinCode(filterSetIdx, NUM_FIXED_FILTER_SETS);
      }
      else
      {
        int useTemporalFilt = (filterSetIdx > NUM_FIXED_FILTER_SETS) ? 1 : 0;
        m_BinEncoder.encodeBin(useTemporalFilt, Ctx::AlfUseTemporalFilt());

        if (useTemporalFilt)
        {
          CHECK((filterSetIdx - (NUM_FIXED_FILTER_SETS + 1)) >= (numAvailableFiltSets - (NUM_FIXED_FILTER_SETS + 1)), "temporal non-latest set");
#if JVET_O0247_ALF_CTB_CODING_REDUNDANCY_REMOVAL
          if (numAps > 2)
          {
#endif
            xWriteTruncBinCode(filterSetIdx - (NUM_FIXED_FILTER_SETS + 1), numAvailableFiltSets - (NUM_FIXED_FILTER_SETS + 1));
#if JVET_O0247_ALF_CTB_CODING_REDUNDANCY_REMOVAL
          }
#endif
        }
        else
        {
          CHECK(filterSetIdx >= NUM_FIXED_FILTER_SETS, "fixed set larger than temporal");
          xWriteTruncBinCode(filterSetIdx, NUM_FIXED_FILTER_SETS);
        }
      }
    }
  }
  else
  {
    CHECK(filterSetIdx >= NUM_FIXED_FILTER_SETS, "fixed set numavail < num_fixed");
    xWriteTruncBinCode(filterSetIdx, NUM_FIXED_FILTER_SETS);
  }
}

//! \}