/work/vvenc/source/Lib/EncoderLib/CABACWriter.cpp

Source
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/** \file     CABACWriter.cpp
 *  \brief    Writer for low level syntax
 */

#include "CABACWriter.h"
#include "EncLib.h"
#include "CommonLib/Contexts.h"
#include "CommonLib/UnitTools.h"
#include "CommonLib/SampleAdaptiveOffset.h"
#include "CommonLib/dtrace_buffer.h"

#include <map>
#include <algorithm>

//! \ingroup EncoderLib
//! \{

namespace vvenc {

void CABACWriter::initCtxModels( const Slice& slice )
{
  int       qp                = slice.sliceQp;
  SliceType sliceType         = slice.sliceType;
  SliceType encCABACTableIdx  = slice.encCABACTableIdx;
  if( !slice.isIntra() && (encCABACTableIdx==VVENC_B_SLICE || encCABACTableIdx==VVENC_P_SLICE) && slice.pps->cabacInitPresent )
  {
    sliceType = encCABACTableIdx;
  }
  m_BinEncoder.reset( qp, (int)sliceType );
}



SliceType xGetCtxInitId( const Slice& slice, const BinEncIf& binEncoder, Ctx& ctxTest )
{
  const CtxStore& ctxStoreTest = static_cast<const CtxStore&>( ctxTest );
  const CtxStore& ctxStoreRef  = static_cast<const CtxStore&>( binEncoder.getCtx() );
  int qp = slice.sliceQp;
  if( !slice.isIntra() )
  {
    SliceType aSliceTypeChoices[] = { VVENC_B_SLICE, VVENC_P_SLICE };
    uint64_t  bestCost                 = std::numeric_limits<uint64_t>::max();
    SliceType bestSliceType       = aSliceTypeChoices[0];
    for (uint32_t idx=0; idx<2; idx++)
    {
      uint64_t  curCost           = 0;
      SliceType curSliceType = aSliceTypeChoices[idx];
      ctxTest.init( qp, (int)curSliceType );
      for( int k = 0; k < Ctx::NumberOfContexts; k++ )
      {
        if( binEncoder.getNumBins(k) > 0 )
        {
          curCost += uint64_t( binEncoder.getNumBins(k) ) * ctxStoreRef[k].estFracExcessBits( ctxStoreTest[k] );
        }
      }
      if (curCost < bestCost)
      {
        bestSliceType = curSliceType;
        bestCost      = curCost;
      }
    }
    return bestSliceType;
  }
  else
  {
    return VVENC_I_SLICE;
  }
}


SliceType CABACWriter::getCtxInitId( const Slice& slice )
{
  return  xGetCtxInitId( slice, m_BinEncoder, m_TestCtx );
}


unsigned estBits( BinEncIf& binEnc, const std::vector<bool>& bins, const Ctx& ctx, const int ctxId, const uint8_t winSize )
{
  binEnc.initCtxAndWinSize( ctxId, ctx, winSize );
  binEnc.start();
  const std::size_t numBins   = bins.size();
  unsigned          startBits = binEnc.getNumWrittenBits();
  for( std::size_t binId = 0; binId < numBins; binId++ )
  {
    unsigned  bin = ( bins[binId] ? 1 : 0 );
    binEnc.encodeBin( bin, ctxId );
  }
  unsigned endBits    = binEnc.getNumWrittenBits();
  unsigned codedBits  = endBits - startBits;
  return   codedBits;
}


//================================================================================
//  clause 7.3.8.1
//--------------------------------------------------------------------------------
//    void  end_of_slice()
//================================================================================

void CABACWriter::end_of_slice()
{
  m_BinEncoder.encodeBinTrm ( 1 );
  m_BinEncoder.finish       ();
}


//================================================================================
//  clause 7.3.8.2
//--------------------------------------------------------------------------------
//    bool  coding_tree_unit( cs, area, qp, ctuRsAddr, skipSao, skipAlf )
//================================================================================

void CABACWriter::coding_tree_unit( CodingStructure& cs, const UnitArea& area, int (&qps)[2], unsigned ctuRsAddr, bool skipSao /* = false */, bool skipAlf /* = false */ )
{
  CUCtx cuCtx( qps[CH_L] );
  Partitioner *partitioner = &m_partitioner[0];

  partitioner->initCtu( area, CH_L, *cs.slice );

  if( !skipSao )
  {
    sao( *cs.slice, ctuRsAddr );
  }

  if (!skipAlf)
  {
    for (int compIdx = 0; compIdx < MAX_NUM_COMP; compIdx++)
    {
      if(cs.slice->alfEnabled[compIdx])
      {
        codeAlfCtuEnabledFlag(cs, ctuRsAddr, compIdx);
        if (isLuma(ComponentID(compIdx)))
        {
          codeAlfCtuFilterIndex(cs, ctuRsAddr);
        }
        if (isChroma(ComponentID(compIdx)))
        {
          codeAlfCtuAlternative(cs, ctuRsAddr, compIdx, &cs.slice->alfAps[cs.slice->chromaApsId]->alfParam );
        }
      }
    }
  }

  if ( !skipAlf )
  {
    for ( int compIdx = 1; compIdx < getNumberValidComponents( cs.pcv->chrFormat ); compIdx++ )
    {
      if (cs.slice->ccAlfFilterParam.ccAlfFilterEnabled[compIdx - 1])
      {
        const int filterCount   = cs.slice->ccAlfFilterParam.ccAlfFilterCount[compIdx - 1];

        const int      ry = ctuRsAddr / cs.pcv->widthInCtus;
        const int      rx = ctuRsAddr % cs.pcv->widthInCtus;
        const Position lumaPos(rx * cs.pcv->maxCUSize, ry * cs.pcv->maxCUSize);

        codeCcAlfFilterControlIdc(cs.slice->ccAlfFilterControl[compIdx - 1][ctuRsAddr], cs, ComponentID(compIdx),
                                  ctuRsAddr, cs.slice->ccAlfFilterControl[compIdx - 1], lumaPos, filterCount);
      }
    }
  }

  if ( CS::isDualITree(cs) && cs.pcv->chrFormat != CHROMA_400 && cs.pcv->maxCUSize > 64 )
  {
    CUCtx chromaCuCtx(qps[CH_C]);
    Partitioner *chromaPartitioner = &m_partitioner[1];
    chromaPartitioner->initCtu(area, CH_C, *cs.slice);
    coding_tree(cs, *partitioner, cuCtx, chromaPartitioner, &chromaCuCtx);
    qps[CH_L] = cuCtx.qp;
    qps[CH_C] = chromaCuCtx.qp;
  }
  else
  {
    coding_tree( cs, *partitioner, cuCtx );
    qps[CH_L] = cuCtx.qp;
    if( CS::isDualITree( cs ) && cs.pcv->chrFormat != CHROMA_400 )
    {
      CUCtx cuCtxChroma( qps[CH_C] );
      partitioner->initCtu( area, CH_C, *cs.slice );
      coding_tree( cs, *partitioner, cuCtxChroma );
      qps[CH_C] = cuCtxChroma.qp;
    }
  }
}


//================================================================================
//  clause 7.3.8.3
//--------------------------------------------------------------------------------
//    void  sao             ( slice, ctuRsAddr )
//    void  sao_block_pars  ( saoPars, bitDepths, sliceEnabled, leftMergeAvail, aboveMergeAvail, onlyEstMergeInfo )
//    void  sao_offset_pars ( ctbPars, compID, sliceEnabled, bitDepth )
//================================================================================

void CABACWriter::sao( const Slice& slice, unsigned ctuRsAddr )
{
  const SPS& sps = *slice.sps;
  if( !sps.saoEnabled )
  {
    return;
  }

  CodingStructure&     cs                     = *slice.pic->cs;
  const PreCalcValues& pcv                    = *cs.pcv;
  const SAOBlkParam&  sao_ctu_pars            = cs.picture->getSAO()[ctuRsAddr];
  bool                slice_sao_luma_flag     = ( slice.saoEnabled[ CH_L ] );
  bool                slice_sao_chroma_flag   = ( slice.saoEnabled[ CH_C ] && sps.chromaFormatIdc != CHROMA_400 );
  if( !slice_sao_luma_flag && !slice_sao_chroma_flag )
  {
    return;
  }

  bool                sliceEnabled[3]         = { slice_sao_luma_flag, slice_sao_chroma_flag, slice_sao_chroma_flag };
  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->maxCUSize, ry * cs.pcv->maxCUSize );
  const unsigned      curSliceIdx             = slice.independentSliceIdx;
  const unsigned      curTileIdx              = cs.pps->getTileIdx( pos );
  bool                leftMergeAvail          = cs.getCURestricted( pos.offset( -(int)pcv.maxCUSize, 0  ), pos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;
  bool                aboveMergeAvail         = cs.getCURestricted( pos.offset( 0, -(int)pcv.maxCUSize ), pos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;
  sao_block_pars( sao_ctu_pars, sps.bitDepths, sliceEnabled, leftMergeAvail, aboveMergeAvail, false );
}


void CABACWriter::sao_block_pars( const SAOBlkParam& saoPars, const BitDepths& bitDepths, const bool* sliceEnabled, bool leftMergeAvail, bool aboveMergeAvail, bool onlyEstMergeInfo )
{
  bool isLeftMerge  = false;
  bool isAboveMerge = false;
  if( leftMergeAvail )
  {
    // sao_merge_left_flag
    isLeftMerge   = ( saoPars[COMP_Y].modeIdc == SAO_MODE_MERGE && saoPars[COMP_Y].typeIdc == SAO_MERGE_LEFT );
    m_BinEncoder.encodeBin( (isLeftMerge), Ctx::SaoMergeFlag() );
  }
  if( aboveMergeAvail && !isLeftMerge )
  {
    // sao_merge_above_flag
    isAboveMerge  = ( saoPars[COMP_Y].modeIdc == SAO_MODE_MERGE && saoPars[COMP_Y].typeIdc == SAO_MERGE_ABOVE );
    m_BinEncoder.encodeBin( (isAboveMerge), Ctx::SaoMergeFlag() );
  }
  if( onlyEstMergeInfo )
  {
    return; //only for RDO
  }
  if( !isLeftMerge && !isAboveMerge )
  {
    // explicit parameters
    for( int compIdx=0; compIdx < MAX_NUM_COMP; compIdx++ )
    {
      sao_offset_pars( saoPars[compIdx], ComponentID(compIdx), sliceEnabled[compIdx], bitDepths[ toChannelType(ComponentID(compIdx)) ] );
    }
  }
}


void CABACWriter::sao_offset_pars( const SAOOffset& ctbPars, ComponentID compID, bool sliceEnabled, int bitDepth )
{
  if( !sliceEnabled )
  {
    CHECK( ctbPars.modeIdc != SAO_MODE_OFF, "Sao must be off, if it is disabled on slice level" );
    return;
  }
  const bool isFirstCompOfChType = ( getFirstComponentOfChannel( toChannelType(compID) ) == compID );

  if( isFirstCompOfChType )
  {
    // sao_type_idx_luma / sao_type_idx_chroma
    if( ctbPars.modeIdc == SAO_MODE_OFF )
    {
      m_BinEncoder.encodeBin  ( 0, Ctx::SaoTypeIdx() );
    }
    else if( ctbPars.typeIdc == SAO_TYPE_BO )
    {
      m_BinEncoder.encodeBin  ( 1, Ctx::SaoTypeIdx() );
      m_BinEncoder.encodeBinEP( 0 );
    }
    else
    {
      CHECK(!( ctbPars.typeIdc < SAO_TYPE_START_BO ), "Unspecified error");
      m_BinEncoder.encodeBin  ( 1, Ctx::SaoTypeIdx() );
      m_BinEncoder.encodeBinEP( 1 );
    }
  }

  if( ctbPars.modeIdc == SAO_MODE_NEW )
  {
    const int maxOffsetQVal = SampleAdaptiveOffset::getMaxOffsetQVal( bitDepth );
    int       numClasses    = ( ctbPars.typeIdc == SAO_TYPE_BO ? 4 : NUM_SAO_EO_CLASSES );
    int       k             = 0;
    int       offset[4];
    for( int i = 0; i < numClasses; i++ )
    {
      if( ctbPars.typeIdc != SAO_TYPE_BO && i == SAO_CLASS_EO_PLAIN )
      {
        continue;
      }
      int classIdx = ( ctbPars.typeIdc == SAO_TYPE_BO ? ( ctbPars.typeAuxInfo + i ) % NUM_SAO_BO_CLASSES : i );
      offset[k++]  = ctbPars.offset[classIdx];
    }

    // sao_offset_abs
    for( int i = 0; i < 4; i++ )
    {
      unsigned absOffset = ( offset[i] < 0 ? -offset[i] : offset[i] );
      unary_max_eqprob( absOffset, maxOffsetQVal );
    }

    // band offset mode
    if( ctbPars.typeIdc == SAO_TYPE_BO )
    {
      // sao_offset_sign
      for( int i = 0; i < 4; i++ )
      {
        if( offset[i] )
        {
          m_BinEncoder.encodeBinEP( (offset[i] < 0) );
        }
      }
      // sao_band_position
      m_BinEncoder.encodeBinsEP( ctbPars.typeAuxInfo, NUM_SAO_BO_CLASSES_LOG2 );
    }
    // edge offset mode
    else
    {
      if( isFirstCompOfChType )
      {
        // sao_eo_class_luma / sao_eo_class_chroma
        CHECK( ctbPars.typeIdc - SAO_TYPE_START_EO < 0, "sao edge offset class is outside valid range" );
        m_BinEncoder.encodeBinsEP( ctbPars.typeIdc - SAO_TYPE_START_EO, NUM_SAO_EO_TYPES_LOG2 );
      }
    }
  }
}


//================================================================================
//  clause 7.3.8.4
//--------------------------------------------------------------------------------
//    void  coding_tree       ( cs, partitioner, cuCtx )
//    void  split_cu_flag     ( split, cs, partitioner )
//    void  split_cu_mode_mt  ( split, cs, partitioner )
//================================================================================

void CABACWriter::coding_tree(const CodingStructure& cs, Partitioner& partitioner, CUCtx& cuCtx, Partitioner* pPartitionerChroma, CUCtx* pCuCtxChroma)
{
  const PPS      &pps         = *cs.pps;
  const UnitArea& currArea    = partitioner.currArea();
  const CodingUnit &cu        = *cs.getCU( currArea.blocks[partitioner.chType], partitioner.chType, partitioner.treeType );

  // Reset delta QP coding flag and ChromaQPAdjustemt coding flag
  //Note: do not reset qg at chroma CU
  if( pps.useDQP && partitioner.currQgEnable() && !isChroma( partitioner.chType ) )
  {
    cuCtx.qgStart    = true;
    cuCtx.isDQPCoded          = false;
  }
  if( cs.slice->chromaQpAdjEnabled && partitioner.currQgChromaEnable() )
  {
    cuCtx.isChromaQpAdjCoded  = false;
  }
  // Reset delta QP coding flag and ChromaQPAdjustemt coding flag
  if (CS::isDualITree(cs) && pPartitionerChroma != nullptr)
  {
    if (pps.useDQP && pPartitionerChroma->currQgEnable())
    {
      pCuCtxChroma->qgStart    = true;
      pCuCtxChroma->isDQPCoded = false;
    }
    if (cs.slice->chromaQpAdjEnabled && pPartitionerChroma->currQgChromaEnable())
    {
      pCuCtxChroma->isChromaQpAdjCoded = false;
    }
  }

  determineNeighborCus( cs, partitioner.currArea(), partitioner.chType, partitioner.treeType );

  const PartSplit splitMode = CU::getSplitAtDepth( cu, partitioner.currDepth );

  split_cu_mode( splitMode, cs, partitioner );

  CHECK( !partitioner.canSplit( splitMode, cs ), "The chosen split mode is invalid!" );

  if( splitMode != CU_DONT_SPLIT )
  {
    if (CS::isDualITree(cs) && pPartitionerChroma != nullptr && (partitioner.currArea().lwidth() >= 64 || partitioner.currArea().lheight() >= 64))
    {
      partitioner.splitCurrArea(CU_QUAD_SPLIT, cs);
      pPartitionerChroma->splitCurrArea(CU_QUAD_SPLIT, cs);
      bool beContinue = true;
      bool lumaContinue = true;
      bool chromaContinue = true;

      while (beContinue)
      {
        if (partitioner.currArea().lwidth() > 64 || partitioner.currArea().lheight() > 64)
        {
          if (cs.picture->blocks[partitioner.chType].contains(partitioner.currArea().blocks[partitioner.chType].pos()))
          {
            coding_tree(cs, partitioner, cuCtx, pPartitionerChroma, pCuCtxChroma);
          }
          lumaContinue = partitioner.nextPart(cs);
          chromaContinue = pPartitionerChroma->nextPart(cs);
          CHECK(lumaContinue != chromaContinue, "luma chroma partition should be matched");
          beContinue = lumaContinue;
        }
        else
        {
          //dual tree coding under 64x64 block
          if (cs.picture->blocks[partitioner.chType].contains(partitioner.currArea().blocks[partitioner.chType].pos()))
          {
            coding_tree(cs, partitioner, cuCtx);
          }
          lumaContinue = partitioner.nextPart(cs);
          if (cs.picture->blocks[pPartitionerChroma->chType].contains(pPartitionerChroma->currArea().blocks[pPartitionerChroma->chType].pos()))
          {
            coding_tree(cs, *pPartitionerChroma, *pCuCtxChroma);
          }
          chromaContinue = pPartitionerChroma->nextPart(cs);
          CHECK(lumaContinue != chromaContinue, "luma chroma partition should be matched");
          beContinue = lumaContinue;
        }
      }
      partitioner.exitCurrSplit();
      pPartitionerChroma->exitCurrSplit();

    }
    else
    {
      const ModeType modeTypeParent = partitioner.modeType;
      const ModeType modeTypeChild = CU::getModeTypeAtDepth( cu, partitioner.currDepth );
      mode_constraint( splitMode, cs, partitioner, modeTypeChild );
      partitioner.modeType = modeTypeChild;

      bool chromaNotSplit = modeTypeParent == MODE_TYPE_ALL && modeTypeChild == MODE_TYPE_INTRA ? true : false;
      CHECK( chromaNotSplit && partitioner.chType != CH_L, "chType must be luma" );
      if( partitioner.treeType == TREE_D )
      {
        partitioner.treeType = chromaNotSplit ? TREE_L : TREE_D;
      }
      partitioner.splitCurrArea( splitMode, cs );

      do
      {
        if( cs.picture->blocks[partitioner.chType].contains( partitioner.currArea().blocks[partitioner.chType].pos() ) )
        {
          coding_tree( cs, partitioner, cuCtx );
        }
      } while( partitioner.nextPart( cs ) );

      partitioner.exitCurrSplit();
      if( chromaNotSplit )
      {
        if (isChromaEnabled(cs.pcv->chrFormat))
        {
          CHECK( partitioner.chType != CH_L, "must be luma status" );
          partitioner.chType = CH_C;
          partitioner.treeType = TREE_C;

          if( cs.picture->blocks[partitioner.chType].contains( partitioner.currArea().blocks[partitioner.chType].pos() ) )
          {
            coding_tree( cs, partitioner, cuCtx );
          }
        }
        //recover
        partitioner.chType = CH_L;
        partitioner.treeType = TREE_D;
      }
      partitioner.modeType = modeTypeParent;
    }
    return;
  }

  // Predict QP on start of quantization group
  if( cuCtx.qgStart )
  {
    cuCtx.qgStart = false;
    cuCtx.qp = CU::predictQP( cu, cuCtx.qp );
  }
  CHECK( cu.treeType != partitioner.treeType, "treeType mismatch" );


  // coding unit
  coding_unit( cu, partitioner, cuCtx );

  if( cu.chType == CH_C )
  {
    DTRACE_COND( (isEncoding()), g_trace_ctx, D_QP, "[chroma CU]x=%d, y=%d, w=%d, h=%d, qp=%d\n", cu.Cb().x, cu.Cb().y, cu.Cb().width, cu.Cb().height, cu.qp );
  }
  else
  {
    DTRACE_COND( ( isEncoding() ), g_trace_ctx, D_QP, "x=%d, y=%d, w=%d, h=%d, qp=%d\n", cu.Y().x, cu.Y().y, cu.Y().width, cu.Y().height, cu.qp );
  }
  DTRACE_BLOCK_REC_COND( ( !isEncoding() ), cs.picture->getRecoBuf( cu ), cu, cu.predMode );
}


void CABACWriter::mode_constraint( const PartSplit split, const CodingStructure& cs, Partitioner& partitioner, const ModeType modeType )
{
  CHECK( split == CU_DONT_SPLIT, "splitMode shall not be no split" );
  int val = CS::signalModeCons( cs, partitioner.currArea(), split, partitioner.modeType);
  if( val == LDT_MODE_TYPE_SIGNAL )
  {
    CHECK( modeType == MODE_TYPE_ALL, "shall not be no constraint case" );
    bool flag = modeType == MODE_TYPE_INTRA;
    int ctxIdx = DeriveCtx::CtxModeConsFlag();
    m_BinEncoder.encodeBin( flag, Ctx::ModeConsFlag( ctxIdx ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "mode_cons_flag() flag=%d\n", flag );
  }
  else if( val == LDT_MODE_TYPE_INFER )
  {
    CHECK( modeType != MODE_TYPE_INTRA, "Wrong mode type" );
  }
  else
  {
    CHECK( modeType != partitioner.modeType, "Wrong mode type" );
  }
}


void CABACWriter::split_cu_mode( const PartSplit split, const CodingStructure& cs, Partitioner& partitioner )
{
  bool canNo, canQt, canBh, canBv, canTh, canTv;
  partitioner.canSplit( cs, canNo, canQt, canBh, canBv, canTh, canTv );

  const bool canSpl[6] = { canNo, canQt, canBh, canBv, canTh, canTv };

  unsigned ctxSplit = 0, ctxQtSplit = 0, ctxBttHV = 0, ctxBttH12 = 0, ctxBttV12;
  DeriveCtx::CtxSplit( partitioner, ctxSplit, ctxQtSplit, ctxBttHV, ctxBttH12, ctxBttV12, canSpl );

  const bool canSplit = canBh || canBv || canTh || canTv || canQt;
  const bool isNo     = split == CU_DONT_SPLIT;

  if( canNo && canSplit )
  {
    m_BinEncoder.encodeBin( !isNo, Ctx::SplitFlag( ctxSplit ) );
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "split_cu_mode() ctx=%d split=%d\n", ctxSplit, !isNo );

  if( isNo )
  {
    return;
  }

  const bool canBtt = canBh || canBv || canTh || canTv;
  const bool isQt   = split == CU_QUAD_SPLIT;

  if( canQt && canBtt )
  {
    m_BinEncoder.encodeBin( isQt, Ctx::SplitQtFlag( ctxQtSplit ) );
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "split_cu_mode() ctx=%d qt=%d\n", ctxQtSplit, isQt );

  if( isQt )
  {
    return;
  }

  const bool canHor = canBh || canTh;
  const bool canVer = canBv || canTv;
  const bool  isVer = split == CU_VERT_SPLIT || split == CU_TRIV_SPLIT;

  if( canVer && canHor )
  {
    m_BinEncoder.encodeBin( isVer, Ctx::SplitHvFlag( ctxBttHV ) );
  }

  const bool can14 = isVer ? canTv : canTh;
  const bool can12 = isVer ? canBv : canBh;
  const bool  is12 = isVer ? ( split == CU_VERT_SPLIT ) : ( split == CU_HORZ_SPLIT );

  if( can12 && can14 )
  {
    m_BinEncoder.encodeBin( is12, Ctx::Split12Flag( isVer ? ctxBttV12 : ctxBttH12 ) );
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "split_cu_mode() ctxHv=%d ctx12=%d mode=%d\n", ctxBttHV, isVer ? ctxBttV12 : ctxBttH12, split );
}


//================================================================================
//  clause 7.3.8.5
//--------------------------------------------------------------------------------
//    void  coding_unit               ( cu, partitioner, cuCtx )
//    void  cu_skip_flag              ( cu )
//    void  pred_mode                 ( cu )
//    void  part_mode                 ( cu )
//    void  cu_pred_data              ( pus )
//    void  cu_lic_flag               ( cu )
//    void  intra_luma_pred_modes     ( pus )
//    void  intra_chroma_pred_mode    ( cu )
//    void  cu_residual               ( cu, partitioner, cuCtx )
//    void  rqt_root_cbf              ( cu )
//    void  end_of_ctu                ( cu, cuCtx )
//================================================================================

void CABACWriter::coding_unit( const CodingUnit& cu, Partitioner& partitioner, CUCtx& cuCtx )
{
  DTRACE( g_trace_ctx, D_SYNTAX, "coding_unit() treeType=%d modeType=%d\n", cu.treeType, cu.modeType );
  STAT_COUNT_CU_MODES( isEncoding() && partitioner.chType == CH_L, g_cuCounters1D[CU_CODED_FINALLY][0][!cu.slice->isIntra() + cu.slice->depth] );
  STAT_COUNT_CU_MODES( isEncoding() && partitioner.chType == CH_L && !cu.slice->isIntra(), g_cuCounters2D[CU_CODED_FINALLY][Log2( cu.lheight() )][Log2( cu.lwidth() )] );

  CodingStructure& cs = *cu.cs;

  // skip flag
  if ((!cs.slice->isIntra() || cs.slice->sps->IBC) && cu.Y().valid())
  {
    cu_skip_flag( cu );
  }
  
  // skip data
  if( cu.skip )
  {
    CHECK( !cu.mergeFlag, "Merge flag has to be on!" );
    prediction_unit ( cu );
    CHECK(cu.colorTransform, "ACT should not be enabled for skip mode");
    end_of_ctu      ( cu, cuCtx );
    return;
  }

  // prediction mode and partitioning data
  pred_mode ( cu );
  if (CU::isIntra(cu))
  {
    adaptive_color_transform(cu);
  }
  if (CU::isPLT(cu))
  {
    THROW("no support");
    return;
  }

  // prediction data ( intra prediction modes / reference indexes + motion vectors )
  cu_pred_data( cu );

  // residual data ( coded block flags + transform coefficient levels )
  cu_residual( cu, partitioner, cuCtx );

  // end of cu
  end_of_ctu( cu, cuCtx );
}


void CABACWriter::cu_skip_flag( const CodingUnit& cu )
{
  unsigned ctxId = DeriveCtx::CtxSkipFlag();

  if ((cu.slice->isIntra() || CU::isConsIntra(cu)) && cu.cs->slice->sps->IBC)
  {
    if (cu.lwidth() < 128 && cu.lheight() < 128) // disable IBC mode larger than 64x64
    {
      m_BinEncoder.encodeBin((cu.skip), Ctx::SkipFlag(ctxId));
      DTRACE(g_trace_ctx, D_SYNTAX, "cu_skip_flag() ctx=%d skip=%d\n", ctxId, cu.skip ? 1 : 0);
    }
    return;
  }
  if ( !cu.cs->slice->sps->IBC && cu.lwidth() == 4 && cu.lheight() == 4 )
  {
    return;
  }
  if( !cu.cs->slice->sps->IBC && CU::isConsIntra(cu) )
  {
    return;
  }
  m_BinEncoder.encodeBin( ( cu.skip ), Ctx::SkipFlag( ctxId ) );

  DTRACE( g_trace_ctx, D_SYNTAX, "cu_skip_flag() ctx=%d skip=%d\n", ctxId, cu.skip ? 1 : 0 );
  if (cu.skip && cu.cs->slice->sps->IBC)
  {
    if (cu.lwidth() < 128 && cu.lheight() < 128 && !CU::isConsInter(cu)) // disable IBC mode larger than 64x64 and disable IBC when only allowing inter mode
    {
      if ( cu.lwidth() == 4 && cu.lheight() == 4 )
      {
        return;
      }
      unsigned ctxidx = DeriveCtx::CtxIBCFlag(cu);
      m_BinEncoder.encodeBin(CU::isIBC(cu) ? 1 : 0, Ctx::IBCFlag(ctxidx));
      DTRACE(g_trace_ctx, D_SYNTAX, "ibc() ctx=%d cu.predMode=%d\n", ctxidx, cu.predMode);
    }
  }
}


void CABACWriter::pred_mode( const CodingUnit& cu )
{
  if (cu.cs->slice->sps->IBC && cu.chType != CH_C)
  {
    if( CU::isConsInter(cu) )
    {
      assert( CU::isInter( cu ) );
      return;
    }

    if ( cu.cs->slice->isIntra() || ( cu.lwidth() == 4 && cu.lheight() == 4 ) || CU::isConsIntra(cu) )
    {
      if (cu.lwidth() < 128 && cu.lheight() < 128) // disable IBC mode larger than 64x64
      {
        unsigned ctxidx = DeriveCtx::CtxIBCFlag(cu);
        m_BinEncoder.encodeBin(CU::isIBC(cu), Ctx::IBCFlag(ctxidx));
      }
      if (!CU::isIBC(cu) && cu.cs->slice->sps->PLT && cu.lwidth() <= 64 && cu.lheight() <= 64 && (cu.lumaSize().width * cu.lumaSize().height > 16))
      {
        m_BinEncoder.encodeBin(CU::isPLT(cu), Ctx::PLTFlag(0));
      }
    }
    else
    {
      if( CU::isConsInter(cu) )
      {
        return;
      }
      m_BinEncoder.encodeBin((CU::isIntra(cu) || CU::isPLT(cu)), Ctx::PredMode(DeriveCtx::CtxPredModeFlag()));
      if (CU::isIntra(cu) || CU::isPLT(cu))
      {
        if (cu.cs->slice->sps->PLT && cu.lwidth() <= 64 && cu.lheight() <= 64 && (cu.lumaSize().width * cu.lumaSize().height > 16))
        {
          m_BinEncoder.encodeBin(CU::isPLT(cu), Ctx::PLTFlag(0));
        }
      }
      else
      {
        if (cu.lwidth() < 128 && cu.lheight() < 128) // disable IBC mode larger than 64x64
        {
          unsigned ctxidx = DeriveCtx::CtxIBCFlag(cu);
          m_BinEncoder.encodeBin(CU::isIBC(cu), Ctx::IBCFlag(ctxidx));
        }
      }
    }
  }
  else
  {
    if( CU::isConsInter(cu) )
    {
      assert( CU::isInter( cu ) );
      return;
    }

    if ( cu.cs->slice->isIntra() || ( cu.lwidth() == 4 && cu.lheight() == 4 ) || CU::isConsIntra(cu) )
    {
      if (cu.cs->slice->sps->PLT && cu.lwidth() <= 64 && cu.lheight() <= 64 && ( ( (!isLuma(cu.chType)) && (cu.chromaSize().width * cu.chromaSize().height > 16) ) || ((isLuma(cu.chType)) && ((cu.lumaSize().width * cu.lumaSize().height) > 16 ) ) ) && (!CU::isLocalSepTree(cu) || isLuma(cu.chType) ) )
      {
        m_BinEncoder.encodeBin((CU::isPLT(cu)), Ctx::PLTFlag(0));
      }
      return;
    }
    m_BinEncoder.encodeBin((CU::isIntra(cu) || CU::isPLT(cu)), Ctx::PredMode(DeriveCtx::CtxPredModeFlag()));
    if ((CU::isIntra(cu) || CU::isPLT(cu)) && cu.cs->slice->sps->PLT && cu.lwidth() <= 64 && cu.lheight() <= 64&& ( ( (!isLuma(cu.chType)) && (cu.chromaSize().width * cu.chromaSize().height > 16) ) || ((isLuma(cu.chType)) && ((cu.lumaSize().width * cu.lumaSize().height) > 16 ) ) ) && (!CU::isLocalSepTree(cu) || isLuma(cu.chType)  ) )
    {
      m_BinEncoder.encodeBin((CU::isPLT(cu)), Ctx::PLTFlag(0));
    }
  }
}


void CABACWriter::bdpcm_mode( const CodingUnit& cu, const ComponentID compID )
{
  if( !cu.cs->sps->BDPCM) return;
  if( !CU::bdpcmAllowed( cu, compID ) ) return;

  int bdpcmMode = cu.bdpcmM[toChannelType(compID)];

  unsigned ctxId = isLuma(compID) ? 0 : 2; 
  m_BinEncoder.encodeBin(bdpcmMode > 0 ? 1 : 0, Ctx::BDPCMMode(ctxId));
  if (bdpcmMode)
  {
    m_BinEncoder.encodeBin(bdpcmMode > 1 ? 1 : 0, Ctx::BDPCMMode(ctxId+1));
  }
  if (isLuma(compID))
  {
    DTRACE(g_trace_ctx, D_SYNTAX, "bdpcm_mode(%d) x=%d, y=%d, w=%d, h=%d, bdpcm=%d\n", CH_L, cu.lumaPos().x, cu.lumaPos().y, cu.lwidth(), cu.lheight(), cu.bdpcmM[CH_L]);
  }
  else
  {
    DTRACE(g_trace_ctx, D_SYNTAX, "bdpcm_mode(%d) x=%d, y=%d, w=%d, h=%d, bdpcm=%d\n", CH_C, cu.chromaPos().x, cu.chromaPos().y, cu.chromaSize().width, cu.chromaSize().height, cu.bdpcmM[CH_C]);
  }
}


void CABACWriter::cu_pred_data( const CodingUnit& cu )
{
  if( CU::isIntra( cu ) )
  {
    if( cu.Y().valid() )
    {
      bdpcm_mode( cu, COMP_Y );
    }
    intra_luma_pred_modes  ( cu );
    if( ( !cu.Y().valid() || ( !CU::isSepTree(cu) && cu.Y().valid() ) ) && isChromaEnabled(cu.chromaFormat) )
    {
      bdpcm_mode( cu, ComponentID(CH_C) );
    } 
    intra_chroma_pred_modes( cu );
    return;
  }
  if (!cu.Y().valid()) // dual tree chroma CU
  {
    return;
  }

  prediction_unit ( cu );
  imv_mode        ( cu );
  affine_amvr_mode( cu );
  cu_bcw_flag     ( cu );
}


void CABACWriter::cu_bcw_flag(const CodingUnit& cu)
{
  if(!CU::isBcwIdxCoded(cu))
  {
    return;
  }

  CHECK(!(BCW_NUM > 1 && (BCW_NUM == 2 || (BCW_NUM & 0x01) == 1)), " !( BCW_NUM > 1 && ( BCW_NUM == 2 || ( BCW_NUM & 0x01 ) == 1 ) ) ");
  const uint8_t bcwCodingIdx = (uint8_t)g_BcwCodingOrder[CU::getValidBcwIdx(cu)];

  const int32_t numBcw = (cu.slice->checkLDC) ? 5 : 3;
  m_BinEncoder.encodeBin((bcwCodingIdx == 0 ? 0 : 1), Ctx::BcwIdx(0));
  if(numBcw > 2 && bcwCodingIdx != 0)
  {
    const uint32_t prefixNumBits = numBcw - 2;
    const uint32_t step = 1;

    uint8_t idx = 1;
    for(int ui = 0; ui < prefixNumBits; ++ui)
    {
      if (bcwCodingIdx == idx)
      {
        m_BinEncoder.encodeBinEP(0);
        break;
      }
      else
      {
        m_BinEncoder.encodeBinEP(1);
        idx += step;
      }
    }
  }

  DTRACE(g_trace_ctx, D_SYNTAX, "cu_bcw_flag() bcw_idx=%d\n", cu.BcwIdx ? 1 : 0);
}


void CABACWriter::xWriteTruncBinCode(uint32_t symbol, uint32_t maxSymbol)
{
  int thresh;
  if (maxSymbol > 256)
  {
    int threshVal = 1 << 8;
    thresh = 8;
    while (threshVal <= maxSymbol)
    {
      thresh++;
      threshVal <<= 1;
    }
    thresh--;
  }
  else
  {
    thresh = g_tbMax[maxSymbol];
  }

  int val = 1 << thresh;
  assert(val <= maxSymbol);
  assert((val << 1) > maxSymbol);
  assert(symbol < maxSymbol);
  int b = maxSymbol - val;
  assert(b < val);
  if (symbol < val - b)
  {
    m_BinEncoder.encodeBinsEP(symbol, thresh);
  }
  else
  {
    symbol += val - b;
    assert(symbol < (val << 1));
    assert((symbol >> 1) >= val - b);
    m_BinEncoder.encodeBinsEP(symbol, thresh + 1);
  }
}


void CABACWriter::extend_ref_line(const CodingUnit& cu)
{
  if ( !cu.Y().valid() || cu.predMode != MODE_INTRA || !isLuma(cu.chType) || cu.bdpcmM[CH_L] )
  {
    return;
  }
  if( !cu.cs->sps->MRL )
  {
    return;
  }

  bool isFirstLineOfCtu = (((cu.block(COMP_Y).y)&((cu.cs->sps)->CTUSize - 1)) == 0);
  if (isFirstLineOfCtu)
  {
    return;
  }
  int multiRefIdx = cu.multiRefIdx;
  if (MRL_NUM_REF_LINES > 1)
  {
    m_BinEncoder.encodeBin(multiRefIdx != MULTI_REF_LINE_IDX[0], Ctx::MultiRefLineIdx(0));
    if (MRL_NUM_REF_LINES > 2 && multiRefIdx != MULTI_REF_LINE_IDX[0])
    {
      m_BinEncoder.encodeBin(multiRefIdx != MULTI_REF_LINE_IDX[1], Ctx::MultiRefLineIdx(1));
    }
  }
}


void CABACWriter::intra_luma_pred_modes( const CodingUnit& cu )
{
  if( !cu.Y().valid() || cu.bdpcmM[CH_L] )
  {
    return;
  }

  mip_flag(cu);
  if (cu.mipFlag)
  {
    mip_pred_modes(cu);
    return;
  }
  extend_ref_line( cu );

  isp_mode( cu );

  const int numMPMs   = NUM_MOST_PROBABLE_MODES;
  unsigned  mpm_pred   [numMPMs];
  unsigned  mpm_idx;
  unsigned  ipred_mode ;

  // prev_intra_luma_pred_flag
  {
    CU::getIntraMPMs( cu, mpm_pred );

    ipred_mode = cu.intraDir[0];
    mpm_idx    = numMPMs;
    for( unsigned idx = 0; idx < numMPMs; idx++ )
    {
      if( ipred_mode == mpm_pred[idx] )
      {
        mpm_idx = idx;
        break;
      }
    }
    if ( cu.multiRefIdx )
    {
      CHECK(mpm_idx >= numMPMs, "use of non-MPM");
    }
    else
    {
      m_BinEncoder.encodeBin(mpm_idx < numMPMs, Ctx::IntraLumaMpmFlag());
    }
  }

  // mpm_idx / rem_intra_luma_pred_mode
  {
    if( mpm_idx < numMPMs )
    {
      {
        unsigned ctx = (cu.ispMode == NOT_INTRA_SUBPARTITIONS ? 1 : 0);
        if (cu.multiRefIdx == 0)
          m_BinEncoder.encodeBin(mpm_idx > 0, Ctx::IntraLumaPlanarFlag(ctx));
        if( mpm_idx )
        {
          m_BinEncoder.encodeBinEP( mpm_idx > 1 );
        }
        if (mpm_idx > 1)
        {
          m_BinEncoder.encodeBinEP(mpm_idx > 2);
        }
        if (mpm_idx > 2)
        {
          m_BinEncoder.encodeBinEP(mpm_idx > 3);
        }
        if (mpm_idx > 3)
        {
          m_BinEncoder.encodeBinEP(mpm_idx > 4);
        }
      }
    }
    else
    {
      // sorting of MPMs
      std::sort( mpm_pred, mpm_pred + numMPMs );

      {
        for (int idx = numMPMs - 1; idx >= 0; idx--)
        {
          if (ipred_mode > mpm_pred[idx])
          {
            ipred_mode--;
          }
        }
        CHECK(ipred_mode >= 64, "Incorrect mode");
        xWriteTruncBinCode(ipred_mode, NUM_LUMA_MODE - NUM_MOST_PROBABLE_MODES);  // Remaining mode is truncated binary coded
      }
    }

    DTRACE( g_trace_ctx, D_SYNTAX, "intra_luma_pred_modes() idx=%d pos=(%d,%d) mode=%d\n", 0, cu.lumaPos().x, cu.lumaPos().y, cu.intraDir[0] );
  }
}


void CABACWriter::intra_luma_pred_mode( const CodingUnit& cu, const unsigned *mpmLst )
{
  if( cu.bdpcmM[CH_L] ) 
  {
    return;
  }

  mip_flag(cu);
  if (cu.mipFlag)
  {
    mip_pred_mode(cu);
    return;
  }
  extend_ref_line( cu );

  isp_mode( cu );

  // prev_intra_luma_pred_flag
  unsigned ipred_mode = cu.intraDir[0];
  static constexpr int numMPMs = NUM_MOST_PROBABLE_MODES;
  unsigned mpm_idx = numMPMs;
  unsigned  mpm_pred[numMPMs];

  if (mpmLst)
  {
    memcpy(mpm_pred, mpmLst, sizeof(unsigned) * numMPMs);
  }
  else
  {
    CU::getIntraMPMs(cu, mpm_pred);
  }

  for (int idx = 0; idx < numMPMs; idx++)
  {
    if (ipred_mode == mpm_pred[idx])
    {
      mpm_idx = idx;
      break;
    }
  }
  if (cu.multiRefIdx)
  {
    CHECK(mpm_idx >= numMPMs, "use of non-MPM");
  }
  else
  {
    m_BinEncoder.encodeBin(mpm_idx < numMPMs, Ctx::IntraLumaMpmFlag());
  }

  // mpm_idx / rem_intra_luma_pred_mode
  if( mpm_idx < numMPMs )
  {
    unsigned ctx = (cu.ispMode == NOT_INTRA_SUBPARTITIONS ? 1 : 0);
    if (cu.multiRefIdx == 0)
      m_BinEncoder.encodeBin( mpm_idx > 0, Ctx::IntraLumaPlanarFlag(ctx) );
    if( mpm_idx )
    {
      m_BinEncoder.encodeBinEP( mpm_idx > 1 );
    }
    if (mpm_idx > 1)
    {
      m_BinEncoder.encodeBinEP(mpm_idx > 2);
    }
    if (mpm_idx > 2)
    {
      m_BinEncoder.encodeBinEP(mpm_idx > 3);
    }
    if (mpm_idx > 3)
    {
      m_BinEncoder.encodeBinEP(mpm_idx > 4);
    }
  }
  else
  {
    // mpm_pred[0] is always 0, i.e. PLANAR, so its always first in the list
    std::sort( mpm_pred + 1, mpm_pred + numMPMs );

    for (int idx = numMPMs - 1; idx >= 0; idx--)
    {
      if (ipred_mode > mpm_pred[idx])
      {
        ipred_mode--;
      }
    }

    xWriteTruncBinCode(ipred_mode, NUM_LUMA_MODE - NUM_MOST_PROBABLE_MODES);  // Remaining mode is truncated binary coded
  }
}


void CABACWriter::intra_chroma_pred_modes( const CodingUnit& cu )
{
  if( cu.chromaFormat == CHROMA_400 || ( CU::isSepTree(cu) && cu.chType == CH_L ) || cu.bdpcmM[CH_C] )
  {
    return;
  }

  intra_chroma_pred_mode( cu );
}


void CABACWriter::intra_chroma_lmc_mode(const CodingUnit& cu)
{
  const unsigned intraDir = cu.intraDir[1];
  int lmModeList[10];
  CU::getLMSymbolList(cu, lmModeList);
  int symbol = -1;
  for (int k = 0; k < LM_SYMBOL_NUM; k++)
  {
    if (lmModeList[k] == intraDir)
    {
      symbol = k;
      break;
    }
  }
  CHECK(symbol < 0, "invalid symbol found");

  m_BinEncoder.encodeBin(symbol == 0 ? 0 : 1, Ctx::CclmModeIdx(0));

  if (symbol > 0)
  {
    CHECK(symbol > 2, "invalid symbol for MMLM");
    unsigned int symbol_minus_1 = symbol - 1;
    m_BinEncoder.encodeBinEP(symbol_minus_1);
  }
}


void CABACWriter::intra_chroma_pred_mode(const CodingUnit& cu)
{
  if (cu.colorTransform)
  {
    CHECK(cu.intraDir[CH_C] != DM_CHROMA_IDX, "chroma should use DM for adaptive color transform");
    return;
  }

  const unsigned intraDir = cu.intraDir[1];
  if (cu.cs->sps->LMChroma && CU::checkCCLMAllowed(cu))
  {
    m_BinEncoder.encodeBin(CU::isLMCMode(intraDir) ? 1 : 0, Ctx::CclmModeFlag(0));
    if (CU::isLMCMode(intraDir))
    {
      intra_chroma_lmc_mode(cu);
      return;
    }
  }

  const bool     isDerivedMode = intraDir == DM_CHROMA_IDX;
  m_BinEncoder.encodeBin(isDerivedMode ? 0 : 1, Ctx::IntraChromaPredMode(0));
  if (isDerivedMode)
  {
    return;
  }

  // chroma candidate index
  unsigned chromaCandModes[NUM_CHROMA_MODE];
  CU::getIntraChromaCandModes(cu, chromaCandModes);

  int candId = 0;
  for (; candId < NUM_CHROMA_MODE; candId++)
  {
    if (intraDir == chromaCandModes[candId])
    {
      break;
    }
  }

  CHECK(candId >= NUM_CHROMA_MODE, "Chroma prediction mode index out of bounds");
  CHECK(chromaCandModes[candId] == DM_CHROMA_IDX, "The intra dir cannot be DM_CHROMA for this path");
  {
    m_BinEncoder.encodeBinsEP(candId, 2);
  }
}


void CABACWriter::cu_residual( const CodingUnit& cu, Partitioner& partitioner, CUCtx& cuCtx )
{
  if (!CU::isIntra(cu))
  {
    if( !cu.mergeFlag )
    {
      rqt_root_cbf( cu );
    }
    if( cu.rootCbf )
    {
      sbt_mode( cu );
    }

    if( !cu.rootCbf )
    {
      CHECK(cu.colorTransform, "ACT should not be enabled for root_cbf = 0");
      return;
    }
  }

  if( CU::isInter( cu ) || CU::isIBC( cu ) )
  {
    adaptive_color_transform(cu);
  }

  cuCtx.violatesLfnstConstrained[CH_L] = false;
  cuCtx.violatesLfnstConstrained[CH_C] = false;
  cuCtx.lfnstLastScanPos               = false;
  cuCtx.violatesMtsCoeffConstraint     = false;
  cuCtx.mtsLastScanPos                                = false;

  if( cu.ispMode && isLuma( partitioner.chType ) )
  {
    transform_tree( *cu.cs, partitioner, cuCtx, CU::getISPType( cu, getFirstComponentOfChannel( partitioner.chType ) ), 0 );
  }
  else
  {
    transform_tree( *cu.cs, partitioner, cuCtx );
  }

  residual_lfnst_mode( cu, cuCtx );
  mts_idx            ( cu, &cuCtx );
}


void CABACWriter::rqt_root_cbf( const CodingUnit& cu )
{
  m_BinEncoder.encodeBin( cu.rootCbf, Ctx::QtRootCbf() );

  DTRACE( g_trace_ctx, D_SYNTAX, "rqt_root_cbf() ctx=0 root_cbf=%d pos=(%d,%d)\n", cu.rootCbf ? 1 : 0, cu.lumaPos().x, cu.lumaPos().y );
}


void CABACWriter::adaptive_color_transform(const CodingUnit& cu)
{
  if (!cu.slice->sps->useColorTrans )
  {
    return;
  }

  if (CU::isSepTree(cu))
  {
    CHECK(cu.colorTransform, "adaptive color transform should be disabled when dualtree and localtree are enabled");
    return;
  }

  if (CU::isInter(cu) || CU::isIBC(cu) || CU::isIntra(cu))
  {
    m_BinEncoder.encodeBin(cu.colorTransform, Ctx::ACTFlag());
  }
}


void CABACWriter::sbt_mode( const CodingUnit& cu )
{
  uint8_t sbtAllowed = CU::checkAllowedSbt(cu);
  if( !sbtAllowed )
  {
    return;
  }

  SizeType cuWidth = cu.lwidth();
  SizeType cuHeight = cu.lheight();
  uint8_t sbtIdx = CU::getSbtIdx( cu.sbtInfo );
  uint8_t sbtPos = CU::getSbtPos( cu.sbtInfo );

  //bin - flag
  bool sbtFlag = cu.sbtInfo != 0;
  uint8_t ctxIdx = ( cuWidth * cuHeight <= 256 ) ? 1 : 0;
  m_BinEncoder.encodeBin( sbtFlag, Ctx::SbtFlag( ctxIdx ) );
  if( !sbtFlag )
  {
    return;
  }

  bool sbtQuadFlag = sbtIdx == SBT_HOR_QUAD || sbtIdx == SBT_VER_QUAD;
  bool sbtHorFlag = sbtIdx == SBT_HOR_HALF || sbtIdx == SBT_HOR_QUAD;
  bool sbtPosFlag = sbtPos == SBT_POS1;

  uint8_t sbtVerHalfAllow = CU::targetSbtAllowed( SBT_VER_HALF, sbtAllowed );
  uint8_t sbtHorHalfAllow = CU::targetSbtAllowed( SBT_HOR_HALF, sbtAllowed );
  uint8_t sbtVerQuadAllow = CU::targetSbtAllowed( SBT_VER_QUAD, sbtAllowed );
  uint8_t sbtHorQuadAllow = CU::targetSbtAllowed( SBT_HOR_QUAD, sbtAllowed );
  //bin - type
  if( ( sbtHorHalfAllow || sbtVerHalfAllow ) && ( sbtHorQuadAllow || sbtVerQuadAllow ) )
  {
    m_BinEncoder.encodeBin( sbtQuadFlag, Ctx::SbtQuadFlag( 0 ) );
  }
  else
  {
    assert( sbtQuadFlag == 0 );
  }

  //bin - dir
  if( ( sbtQuadFlag && sbtVerQuadAllow && sbtHorQuadAllow ) || ( !sbtQuadFlag && sbtVerHalfAllow && sbtHorHalfAllow ) ) //both direction allowed
  {
    uint8_t ctxIdx = ( cuWidth == cuHeight ) ? 0 : ( cuWidth < cuHeight ? 1 : 2 );
    m_BinEncoder.encodeBin( sbtHorFlag, Ctx::SbtHorFlag( ctxIdx ) );
  }
  else
  {
    assert( sbtHorFlag == ( ( sbtQuadFlag && sbtHorQuadAllow ) || ( !sbtQuadFlag && sbtHorHalfAllow ) ) );
  }

  //bin - pos
  m_BinEncoder.encodeBin( sbtPosFlag, Ctx::SbtPosFlag( 0 ) );

  DTRACE( g_trace_ctx, D_SYNTAX, "sbt_mode() pos=(%d,%d) sbtInfo=%d\n", cu.lx(), cu.ly(), (int)cu.sbtInfo );
}


void CABACWriter::end_of_ctu( const CodingUnit& cu, CUCtx& cuCtx )
{
  const bool    isLastSubCUOfCtu  = CU::isLastSubCUOfCtu( cu );

  if ( isLastSubCUOfCtu
    && ( !CU::isSepTree(cu) || cu.chromaFormat == CHROMA_400 || isChroma( cu.chType ) )
      )
  {
    cuCtx.isDQPCoded = ( cu.cs->pps->useDQP && !cuCtx.isDQPCoded );

  }
}


void CABACWriter::cu_palette_info(const CodingUnit& cu, ComponentID compBegin, uint32_t numComp, CUCtx& cuCtx)
{
  THROW("no support");
}


//================================================================================
//  clause 7.3.8.6
//--------------------------------------------------------------------------------
//    void  prediction_unit ( cu );
//    void  merge_flag      ( cu );
//    void  merge_idx       ( cu );
//    void  inter_pred_idc  ( cu );
//    void  ref_idx         ( cu, refList );
//    void  mvp_flag        ( cu, refList );
//================================================================================

void CABACWriter::prediction_unit( const CodingUnit& cu )
{
  CHECK( cu.treeType == TREE_C, "cannot be chroma CU" );
  if( cu.skip )
  {
    CHECK( !cu.mergeFlag, "merge_flag must be true for skipped CUs" );
  }
  else
  {
    merge_flag( cu );
  }
  if( cu.mergeFlag )
  {
    merge_data(cu);
  }
  else if (CU::isIBC(cu))
  {
    ref_idx(cu, REF_PIC_LIST_0);
    Mv mvd = cu.mvd[REF_PIC_LIST_0][0];
    mvd.changeIbcPrecInternal2Amvr(cu.imv);
    mvd_coding(mvd, 0); // already changed to signaling precision
    if ( cu.slice->sps->maxNumIBCMergeCand == 1 )
    {
      CHECK( cu.mvpIdx[REF_PIC_LIST_0], "mvpIdx for IBC mode should be 0" );
    }
    else
    mvp_flag(cu, REF_PIC_LIST_0);
  }
  else
  {
    inter_pred_idc( cu );
    affine_flag   ( cu );
    smvd_mode( cu );
    if( cu.interDir != 2 /* PRED_L1 */ )
    {
      ref_idx     ( cu, REF_PIC_LIST_0 );
      if ( cu.affine )
      {
        Mv mvd = cu.mvd[REF_PIC_LIST_0][0];
        mvd.changeAffinePrecInternal2Amvr(cu.imv);
        mvd_coding(mvd, 0); // already changed to signaling precision
        mvd = cu.mvd[REF_PIC_LIST_0][1];
        mvd.changeAffinePrecInternal2Amvr(cu.imv);
        mvd_coding(mvd, 0); // already changed to signaling precision
        if ( cu.affineType == AFFINEMODEL_6PARAM )
        {
          mvd = cu.mvd[REF_PIC_LIST_0][2];
          mvd.changeAffinePrecInternal2Amvr(cu.imv);
          mvd_coding(mvd, 0); // already changed to signaling precision
        }
      }
      else
      {
        Mv mvd = cu.mvd[REF_PIC_LIST_0][0];
        mvd.changeTransPrecInternal2Amvr(cu.imv);
        mvd_coding(mvd, 0); // already changed to signaling precision
      }
      mvp_flag    ( cu, REF_PIC_LIST_0 );
    }
    if( cu.interDir != 1 /* PRED_L0 */ )
    {
      if ( cu.smvdMode != 1 )
      {
        ref_idx     ( cu, REF_PIC_LIST_1 );
        if( !cu.cs->picHeader->mvdL1Zero || cu.interDir != 3 /* PRED_BI */ )
        {
          if ( cu.affine )
          {
            Mv mvd = cu.mvd[REF_PIC_LIST_1][0];
            mvd.changeAffinePrecInternal2Amvr(cu.imv);
            mvd_coding(mvd, 0); // already changed to signaling precision
            mvd = cu.mvd[REF_PIC_LIST_1][1];
            mvd.changeAffinePrecInternal2Amvr(cu.imv);
            mvd_coding(mvd, 0); // already changed to signaling precision
            if ( cu.affineType == AFFINEMODEL_6PARAM )
            {
              mvd = cu.mvd[REF_PIC_LIST_1][2];
              mvd.changeAffinePrecInternal2Amvr(cu.imv);
              mvd_coding(mvd, 0); // already changed to signaling precision
            }
          }
          else
          {
            Mv mvd = cu.mvd[REF_PIC_LIST_1][0];
            mvd.changeTransPrecInternal2Amvr(cu.imv);
            mvd_coding(mvd, 0); // already changed to signaling precision
          }
        }
      }
      mvp_flag    ( cu, REF_PIC_LIST_1 );
    }
  }
}


void CABACWriter::smvd_mode( const CodingUnit& cu )
{
  if ( cu.interDir != 3 || cu.affine )
  {
    return;
  }

  if ( cu.cs->slice->biDirPred == false )
  {
    return;
  }

  m_BinEncoder.encodeBin( cu.smvdMode ? 1 : 0, Ctx::SmvdFlag() );

  DTRACE( g_trace_ctx, D_SYNTAX, "symmvd_flag() symmvd=%d pos=(%d,%d) size=%dx%d\n", cu.smvdMode ? 1 : 0, cu.lumaPos().x, cu.lumaPos().y, cu.lumaSize().width, cu.lumaSize().height );
}


void CABACWriter::subblock_merge_flag( const CodingUnit& cu )
{

  if ( !cu.cs->slice->isIntra() && (cu.slice->picHeader->maxNumAffineMergeCand > 0) && cu.lumaSize().width >= 8 && cu.lumaSize().height >= 8 )
  {
    unsigned ctxId = DeriveCtx::CtxAffineFlag();
    m_BinEncoder.encodeBin( cu.affine, Ctx::SubblockMergeFlag( ctxId ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "subblock_merge_flag() subblock_merge_flag=%d ctx=%d pos=(%d,%d)\n", cu.affine ? 1 : 0, ctxId, cu.Y().x, cu.Y().y );
  }
}


void CABACWriter::affine_flag( const CodingUnit& cu )
{
  if ( !cu.cs->slice->isIntra() && cu.cs->sps->Affine && cu.lumaSize().width > 8 && cu.lumaSize().height > 8 )
  {
    unsigned ctxId = DeriveCtx::CtxAffineFlag();
    m_BinEncoder.encodeBin( cu.affine, Ctx::AffineFlag( ctxId ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "affine_flag() affine=%d ctx=%d pos=(%d,%d)\n", cu.affine ? 1 : 0, ctxId, cu.Y().x, cu.Y().y );

    if ( cu.affine && cu.cs->sps->AffineType )
    {
      unsigned ctxId = 0;
      m_BinEncoder.encodeBin( cu.affineType, Ctx::AffineType( ctxId ) );
      DTRACE( g_trace_ctx, D_SYNTAX, "affine_type() affine_type=%d ctx=%d pos=(%d,%d)\n", cu.affineType ? 1 : 0, ctxId, cu.Y().x, cu.Y().y );
    }
  }
}


void CABACWriter::merge_flag( const CodingUnit& cu )
{
  m_BinEncoder.encodeBin( cu.mergeFlag, Ctx::MergeFlag() );

  DTRACE( g_trace_ctx, D_SYNTAX, "merge_flag() merge=%d pos=(%d,%d) size=%dx%d\n", cu.mergeFlag ? 1 : 0, cu.lumaPos().x, cu.lumaPos().y, cu.lumaSize().width, cu.lumaSize().height );
}


void CABACWriter::merge_data(const CodingUnit& cu)
{
  if (CU::isIBC(cu))
  {
    merge_idx(cu);
    return;
  }
  subblock_merge_flag(cu);
  if (cu.affine)
  {
    merge_idx(cu);
    return;
  }

  const bool ciipAvailable = cu.cs->sps->CIIP && !cu.skip && cu.Y().maxDim() < MAX_CU_SIZE && cu.Y().area() >= 64;
  const bool geoAvailable = cu.cs->slice->sps->GEO && cu.cs->slice->isInterB() && cu.cs->sps->maxNumGeoCand > 1
                                                   && cu.Y().minDim() >= GEO_MIN_CU_SIZE && cu.Y().maxDim() <= GEO_MAX_CU_SIZE
                                                   && cu.Y().maxDim() < 8 * cu.Y().minDim();

  if (geoAvailable || ciipAvailable)
  {
    m_BinEncoder.encodeBin(!cu.geo && !cu.ciip, Ctx::RegularMergeFlag(cu.skip ? 0 : 1));
  }
  if (!cu.geo && !cu.ciip)
  {
    if (cu.cs->sps->MMVD)
    {
      m_BinEncoder.encodeBin(cu.mmvdMergeFlag, Ctx::MmvdFlag(0));
      DTRACE(g_trace_ctx, D_SYNTAX, "mmvd_merge_flag() mmvd_merge=%d pos=(%d,%d) size=%dx%d\n", cu.mmvdMergeFlag ? 1 : 0, cu.lumaPos().x, cu.lumaPos().y, cu.lumaSize().width, cu.lumaSize().height);
    }
    if (cu.mmvdMergeFlag || cu.mmvdSkip)
    {
      mmvd_merge_idx(cu);
    }
    else
    {
      merge_idx(cu);
    }
  }
  else
  {
    if (geoAvailable && ciipAvailable)
    {
      ciip_flag(cu);
    }
    merge_idx(cu);
  }
}


void CABACWriter::imv_mode( const CodingUnit& cu )
{
  const SPS *sps = cu.cs->sps;

  if( !sps->AMVR )
  {
    return;
  }
  if ( cu.affine )
  {
    return;
  }

  bool bNonZeroMvd = CU::hasSubCUNonZeroMVd( cu );
  if( !bNonZeroMvd )
  {
    return;
  }

  if (CU::isIBC(cu) == false)
    m_BinEncoder.encodeBin( (cu.imv > 0), Ctx::ImvFlag( 0 ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "imv_mode() value=%d ctx=%d\n", (cu.imv > 0), 0 );

  if( sps->AMVR && cu.imv > 0 )
  {
    if (!CU::isIBC(cu))
    {
      m_BinEncoder.encodeBin(cu.imv < IMV_HPEL, Ctx::ImvFlag(4));
      DTRACE(g_trace_ctx, D_SYNTAX, "imv_mode() value=%d ctx=%d\n", cu.imv < 3, 4);
    }
    if (cu.imv < IMV_HPEL)
    {
    m_BinEncoder.encodeBin( (cu.imv > 1), Ctx::ImvFlag( 1 ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "imv_mode() value=%d ctx=%d\n", (cu.imv > 1), 1 );
    }
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "imv_mode() IMVFlag=%d\n", cu.imv );
}


void CABACWriter::affine_amvr_mode( const CodingUnit& cu )
{
  const SPS* sps = cu.slice->sps;

  if( !sps->AffineAmvr || !cu.affine )
  {
    return;
  }

  if ( !CU::hasSubCUNonZeroAffineMVd( cu ) )
  {
    return;
  }

  m_BinEncoder.encodeBin( (cu.imv > 0), Ctx::ImvFlag( 2 ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "affine_amvr_mode() value=%d ctx=%d\n", (cu.imv > 0), 2 );

  if( cu.imv > 0 )
  {
    m_BinEncoder.encodeBin( (cu.imv > 1), Ctx::ImvFlag( 3 ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "affine_amvr_mode() value=%d ctx=%d\n", (cu.imv > 1), 3 );
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "affine_amvr_mode() IMVFlag=%d\n", cu.imv );
}


void CABACWriter::merge_idx( const CodingUnit& cu )
{
  if ( cu.affine )
  {
    int numCandminus1 = int( cu.cs->picHeader->maxNumAffineMergeCand ) - 1;
    if ( numCandminus1 > 0 )
    {
      if ( cu.mergeIdx == 0 )
      {
        m_BinEncoder.encodeBin( 0, Ctx::AffMergeIdx() );
        DTRACE( g_trace_ctx, D_SYNTAX, "aff_merge_idx() aff_merge_idx=%d\n", cu.mergeIdx );
        return;
      }
      else
      {
        m_BinEncoder.encodeBin( 1, Ctx::AffMergeIdx() );
        for ( unsigned idx = 1; idx < numCandminus1; idx++ )
        {
            m_BinEncoder.encodeBinEP( cu.mergeIdx == idx ? 0 : 1 );
          if ( cu.mergeIdx == idx )
          {
            break;
          }
        }
      }
    }
    DTRACE( g_trace_ctx, D_SYNTAX, "aff_merge_idx() aff_merge_idx=%d\n", cu.mergeIdx );
  }
  else
  {
    if( cu.geo )
    {
      uint8_t splitDir = cu.geoSplitDir;
      uint8_t candIdx0 = cu.geoMergeIdx[0];
      uint8_t candIdx1 = cu.geoMergeIdx[1];
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() geo_split_dir=%d\n", splitDir );
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() geo_idx0=%d\n", candIdx0 );
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() geo_idx1=%d\n", candIdx1 );
      xWriteTruncBinCode(splitDir, GEO_NUM_PARTITION_MODE);
      candIdx1 -= candIdx1 < candIdx0 ? 0 : 1;
      const int maxNumGeoCand = cu.cs->sps->maxNumGeoCand;
      CHECK(maxNumGeoCand < 2, "Incorrect max number of geo candidates");
      CHECK(candIdx0 >= maxNumGeoCand, "Incorrect candIdx0");
      CHECK(candIdx1 >= maxNumGeoCand, "Incorrect candIdx1");
      int numCandminus2 = maxNumGeoCand - 2;
      m_BinEncoder.encodeBin( candIdx0 == 0 ? 0 : 1, Ctx::MergeIdx() );
      if( candIdx0 > 0 )
      {
        unary_max_eqprob(candIdx0 - 1, numCandminus2);
      }
      if (numCandminus2 > 0)
      {
        m_BinEncoder.encodeBin(candIdx1 == 0 ? 0 : 1, Ctx::MergeIdx());
        if (candIdx1 > 0)
        {
          unary_max_eqprob(candIdx1 - 1, numCandminus2 - 1);
        }
      }
      return;
    }
    int numCandminus1 = (cu.predMode == MODE_IBC) ? (int(cu.cs->sps->maxNumIBCMergeCand) - 1) : (int(cu.cs->sps->maxNumMergeCand) - 1);
    if( numCandminus1 > 0 )
    {
      if( cu.mergeIdx == 0 )
      {
        m_BinEncoder.encodeBin( 0, Ctx::MergeIdx() );
        DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() merge_idx=%d\n", cu.mergeIdx );
        return;
      }
      else
      {
        m_BinEncoder.encodeBin( 1, Ctx::MergeIdx() );
        for( unsigned idx = 1; idx < numCandminus1; idx++ )
        {
          m_BinEncoder.encodeBinEP( cu.mergeIdx == idx ? 0 : 1 );
          if( cu.mergeIdx == idx )
          {
            break;
          }
        }
      }
    }
    DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() merge_idx=%d\n", cu.mergeIdx );
  }
}


void CABACWriter::mmvd_merge_idx( const CodingUnit &cu )
{
  const int mvdBaseIdx  = cu.mmvdMergeIdx.pos.baseIdx;
  const int mvdStep     = cu.mmvdMergeIdx.pos.step;
  const int mvdPosition = cu.mmvdMergeIdx.pos.position;

  if( cu.cs->sps->maxNumMergeCand > 1 )
  {
    static_assert( MMVD_BASE_MV_NUM == 2, "" );
    CHECK( mvdBaseIdx >= 2, "Invalid mvdBaseIdx" );
    m_BinEncoder.encodeBin( mvdBaseIdx, Ctx::MmvdMergeIdx() );
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "base_mvp_idx() base_mvp_idx=%d\n", mvdBaseIdx );

  int numCandminus1_step = MMVD_REFINE_STEP - 1;
  if( numCandminus1_step > 0 )
  {
    if( mvdStep == 0 )
    {
      m_BinEncoder.encodeBin( 0, Ctx::MmvdStepMvpIdx() );
    }
    else
    {
      m_BinEncoder.encodeBin( 1, Ctx::MmvdStepMvpIdx() );
      for( unsigned idx = 1; idx < numCandminus1_step; idx++ )
      {
        m_BinEncoder.encodeBinEP( mvdStep == idx ? 0 : 1 );
        if( mvdStep == idx )
        {
          break;
        }
      }
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "MmvdStepMvpIdx() MmvdStepMvpIdx=%d\n", mvdStep );

  m_BinEncoder.encodeBinsEP( mvdPosition, 2 );

  DTRACE( g_trace_ctx, D_SYNTAX, "pos() pos=%d\n", mvdPosition );
  DTRACE( g_trace_ctx, D_SYNTAX, "mmvd_merge_idx() mmvd_merge_idx=%d\n", cu.mmvdMergeIdx.val );
}


void CABACWriter::inter_pred_idc( const CodingUnit& cu )
{
  if( !cu.cs->slice->isInterB() )
  {
    return;
  }
  if( !(CU::isBipredRestriction(cu)) )
  {
    unsigned ctxId = DeriveCtx::CtxInterDir(cu);
    if( cu.interDir == 3 )
    {
      m_BinEncoder.encodeBin( 1, Ctx::InterDir(ctxId) );
      DTRACE( g_trace_ctx, D_SYNTAX, "inter_pred_idc() ctx=%d value=%d pos=(%d,%d)\n", ctxId, cu.interDir, cu.lumaPos().x, cu.lumaPos().y );
      return;
    }
    else
    {
      m_BinEncoder.encodeBin( 0, Ctx::InterDir(ctxId) );
    }
  }
  m_BinEncoder.encodeBin( ( cu.interDir == 2 ), Ctx::InterDir( 5 ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "inter_pred_idc() ctx=5 value=%d pos=(%d,%d)\n", cu.interDir, cu.lumaPos().x, cu.lumaPos().y );
}


void CABACWriter::ref_idx( const CodingUnit& cu, RefPicList eRefList )
{
  if ( cu.smvdMode )
  {
    CHECK( cu.refIdx[eRefList] != cu.cs->slice->symRefIdx[ eRefList ], "Invalid reference index!\n" );
    return;
  }

  int numRef  = cu.cs->slice->numRefIdx[eRefList];

  if (eRefList == REF_PIC_LIST_0 && cu.cs->sps->IBC)
  {
    if (CU::isIBC(cu))
      return;
  }

  if( numRef <= 1 )
  {
    return;
  }
  int refIdx  = cu.refIdx[eRefList];
  m_BinEncoder.encodeBin( (refIdx > 0), Ctx::RefPic() );
  if( numRef <= 2 || refIdx == 0 )
  {
    DTRACE( g_trace_ctx, D_SYNTAX, "ref_idx() value=%d pos=(%d,%d)\n", refIdx, cu.lumaPos().x, cu.lumaPos().y );
    return;
  }
  m_BinEncoder.encodeBin( (refIdx > 1), Ctx::RefPic(1) );
  if( numRef <= 3 || refIdx == 1 )
  {
    DTRACE( g_trace_ctx, D_SYNTAX, "ref_idx() value=%d pos=(%d,%d)\n", refIdx, cu.lumaPos().x, cu.lumaPos().y );
    return;
  }
  for( int idx = 3; idx < numRef; idx++ )
  {
    if( refIdx > idx - 1 )
    {
      m_BinEncoder.encodeBinEP( 1 );
    }
    else
    {
      m_BinEncoder.encodeBinEP( 0 );
      break;
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "ref_idx() value=%d pos=(%d,%d)\n", refIdx, cu.lumaPos().x, cu.lumaPos().y );
}


void CABACWriter::mvp_flag( const CodingUnit& cu, RefPicList eRefList )
{
  m_BinEncoder.encodeBin( cu.mvpIdx[eRefList], Ctx::MVPIdx() );
  DTRACE( g_trace_ctx, D_SYNTAX, "mvp_flag() value=%d pos=(%d,%d)\n", cu.mvpIdx[eRefList], cu.lumaPos().x, cu.lumaPos().y );
  DTRACE( g_trace_ctx, D_SYNTAX, "mvpIdx(refList:%d)=%d\n", eRefList, cu.mvpIdx[eRefList] );
}


void CABACWriter::ciip_flag(const CodingUnit& cu)
{
  if (!cu.cs->sps->CIIP)
  {
    CHECK(cu.ciip == true, "invalid Ciip SPS");
    return;
  }
  if (cu.skip)
  {
    CHECK(cu.ciip == true, "invalid Ciip and skip");
    return;
  }
  m_BinEncoder.encodeBin(cu.ciip, Ctx::CiipFlag());
  DTRACE(g_trace_ctx, D_SYNTAX, "Ciip_flag() Ciip=%d pos=(%d,%d) size=%dx%d\n", cu.ciip ? 1 : 0, cu.lumaPos().x, cu.lumaPos().y, cu.lumaSize().width, cu.lumaSize().height);
}


//================================================================================
//  clause 7.3.8.8
//--------------------------------------------------------------------------------
//    void  transform_tree      ( cs, area, cuCtx, chromaCbfs )
//    bool  split_transform_flag( split, depth )
//    bool  cbf_comp            ( cbf, area, depth )
//================================================================================

void CABACWriter::transform_tree( const CodingStructure& cs, Partitioner& partitioner, CUCtx& cuCtx, const PartSplit ispType, const int subTuIdx )
{
  const UnitArea&       area = partitioner.currArea();
  int             subTuCounter = subTuIdx;
  const TransformUnit&  tu = *cs.getTU(area.blocks[partitioner.chType].pos(), partitioner.chType, subTuIdx);
  const CodingUnit&     cu = *tu.cu;
  const unsigned        trDepth = partitioner.currTrDepth;
  const bool            split = (tu.depth > trDepth);
  if( split )
  {
    PartSplit partSplit;

    if( partitioner.canSplit( TU_MAX_TR_SPLIT, cs ) )
    {
#if ENABLE_TRACING
      const CompArea& tuArea = partitioner.currArea().blocks[partitioner.chType];
      DTRACE( g_trace_ctx, D_SYNTAX, "transform_tree() maxTrSplit chType=%d pos=(%d,%d) size=%dx%d\n", partitioner.chType, tuArea.x, tuArea.y, tuArea.width, tuArea.height );

#endif
      partitioner.splitCurrArea( TU_MAX_TR_SPLIT, cs );
    }
    else if( cu.ispMode )
    {
      partitioner.splitCurrArea( ispType, cs );
    }
    else if( cu.sbtInfo && partitioner.canSplit( partSplit = CU::getSbtTuSplit( cu.sbtInfo ), cs ) )
    {
      partitioner.splitCurrArea( partSplit, cs );
    }
    else
      THROW( "Implicit TU split not available" );

    do
    {
      transform_tree( cs, partitioner, cuCtx,                ispType, subTuCounter );
      subTuCounter += subTuCounter != -1 ? 1 : 0;
    } while( partitioner.nextPart( cs ) );

    partitioner.exitCurrSplit();
  }
  else
  {
    // split_transform_flag
    CHECK( partitioner.canSplit( TU_MAX_TR_SPLIT, cs ) || (cu.sbtInfo && partitioner.canSplit( CU::getSbtTuSplit( cu.sbtInfo ), cs)),  "transform split implied" );
    DTRACE( g_trace_ctx, D_SYNTAX, "transform_unit() pos=(%d,%d) size=%dx%d depth=%d trDepth=%d\n", tu.blocks[tu.chType].x, tu.blocks[tu.chType].y, tu.blocks[tu.chType].width, tu.blocks[tu.chType].height, cu.depth, partitioner.currTrDepth );

    transform_unit( tu, cuCtx, partitioner, subTuCounter);
  }
}


void CABACWriter::cbf_comp( const CodingUnit& cu, bool cbf, const CompArea& area, unsigned depth, const bool prevCbf, const bool useISP )
{
  const CtxSet&   ctxSet  = Ctx::QtCbf[ area.compID ];
  unsigned  ctxId;
  if( cu.bdpcmM[toChannelType(area.compID)] )
  {
    ctxId = (area.compID != COMP_Cr) ? 1 : 2;
    m_BinEncoder.encodeBin(cbf, ctxSet(ctxId));
  }
  else
  {
    ctxId = DeriveCtx::CtxQtCbf(area.compID, prevCbf, useISP && isLuma(area.compID));
    m_BinEncoder.encodeBin( cbf, ctxSet( ctxId ) );
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "cbf_comp() etype=%d pos=(%d,%d) ctx=%d cbf=%d\n", area.compID, area.x, area.y, ctxId, cbf );
}



//================================================================================
//  clause 7.3.8.9
//--------------------------------------------------------------------------------
//    void  mvd_coding( cu, refList )
//================================================================================
void CABACWriter::mvd_coding( const Mv &rMvd, int8_t imv )
{
  int       horMvd = rMvd.hor;
  int       verMvd = rMvd.ver;
  if ( imv > 0 )
  {
    int shift = 1;
    if (imv < IMV_HPEL)
    {
      shift = 2;
      if (imv == IMV_4PEL)
      {
        shift = 4;
      }
    }

    CHECK((horMvd % (1<<shift)) != 0 && (verMvd % (4<<shift)) != 0, "IMV: MVD is not a multiple of 2^N ");
    horMvd >>= shift;
    verMvd >>= shift;
  }
  unsigned  horAbs  = unsigned( horMvd < 0 ? -horMvd : horMvd );
  unsigned  verAbs  = unsigned( verMvd < 0 ? -verMvd : verMvd );


  // abs_mvd_greater0_flag[ 0 | 1 ]
  m_BinEncoder.encodeBin( (horAbs > 0), Ctx::Mvd() );
  m_BinEncoder.encodeBin( (verAbs > 0), Ctx::Mvd() );

  // abs_mvd_greater1_flag[ 0 | 1 ]
  if( horAbs > 0 )
  {
    m_BinEncoder.encodeBin( (horAbs > 1), Ctx::Mvd(1) );
  }
  if( verAbs > 0 )
  {
    m_BinEncoder.encodeBin( (verAbs > 1), Ctx::Mvd(1) );
  }

  // abs_mvd_minus2[ 0 | 1 ] and mvd_sign_flag[ 0 | 1 ]
  if( horAbs > 0 )
  {
    if( horAbs > 1 )
    {
      m_BinEncoder.encodeRemAbsEP(horAbs - 2, 1, 0, MV_BITS - 1);
    }
    m_BinEncoder.encodeBinEP( (horMvd < 0) );
  }
  if( verAbs > 0 )
  {
    if( verAbs > 1 )
    {
      m_BinEncoder.encodeRemAbsEP(verAbs - 2, 1, 0, MV_BITS - 1);
    }
    m_BinEncoder.encodeBinEP( (verMvd < 0) );
  }
}


//================================================================================
//  clause 7.3.8.10
//--------------------------------------------------------------------------------
//    void  transform_unit      ( tu, cuCtx, chromaCbfs )
//    void  cu_qp_delta         ( cu )
//    void  cu_chroma_qp_offset ( cu )
//================================================================================
void CABACWriter::transform_unit( const TransformUnit& tu, CUCtx& cuCtx, Partitioner& partitioner, const int subTuCounter)
{
  const CodingUnit&       cu = *tu.cu;
  const UnitArea&         area = partitioner.currArea();
  const unsigned          trDepth = partitioner.currTrDepth;
  ChromaCbfs              chromaCbfs;
  CHECK(tu.depth != trDepth, " transform unit should be not be futher partitioned");

  // cbf_cb & cbf_cr
  if (area.chromaFormat != CHROMA_400)
  {
    const bool              chromaCbfISP = area.blocks[COMP_Cb].valid() && cu.ispMode;
    if (area.blocks[COMP_Cb].valid() && (!CU::isSepTree(cu) || partitioner.chType == CH_C) && (!cu.ispMode || chromaCbfISP))
    {
      unsigned cbfDepth = chromaCbfISP ? trDepth - 1 : trDepth;
      {
        chromaCbfs.Cb = TU::getCbfAtDepth(tu, COMP_Cb, trDepth);
        //if (!(cu.sbtInfo && trDepth == 1))
        if (!(cu.sbtInfo && tu.noResidual))
          cbf_comp(*tu.cu, chromaCbfs.Cb, area.blocks[COMP_Cb], cbfDepth);
      }

      {
        chromaCbfs.Cr = TU::getCbfAtDepth(tu, COMP_Cr, trDepth);
        //if (!(cu.sbtInfo && trDepth == 1))
        if (!(cu.sbtInfo && tu.noResidual))
          cbf_comp(*tu.cu, chromaCbfs.Cr, area.blocks[COMP_Cr], cbfDepth, chromaCbfs.Cb);
      }
    }
    else if (CU::isSepTree(cu))
    {
      chromaCbfs = ChromaCbfs(false);
    }
  }
  else if (CU::isSepTree(cu))
  {
    chromaCbfs = ChromaCbfs(false);
  }

  if (!isChroma(partitioner.chType))
  {
    if (!CU::isIntra(cu) && trDepth == 0 && !chromaCbfs.sigChroma(area.chromaFormat))
    {
      CHECK(!TU::getCbfAtDepth(tu, COMP_Y, trDepth), "Luma cbf must be true for inter units with no chroma coeffs");
    }
    else if (cu.sbtInfo && tu.noResidual)
    {
      CHECK(TU::getCbfAtDepth(tu, COMP_Y, trDepth), "Luma cbf must be false for inter sbt no-residual tu");
    }
    else if (cu.sbtInfo && !chromaCbfs.sigChroma(area.chromaFormat))
    {
      assert(!tu.noResidual);
      CHECK(!TU::getCbfAtDepth(tu, COMP_Y, trDepth), "Luma cbf must be true for inter sbt residual tu");
    }
    else
    {
      bool previousCbf = false;
      bool rootCbfSoFar = false;
      bool lumaCbfIsInferredACT = (cu.colorTransform && cu.predMode == MODE_INTRA && trDepth == 0 && !chromaCbfs.sigChroma(area.chromaFormat));
      CHECK(lumaCbfIsInferredACT && !TU::getCbfAtDepth(tu, COMP_Y, trDepth), "adaptive color transform cannot have all zero coefficients");
      bool lastCbfIsInferred    = lumaCbfIsInferredACT; // ISP and ACT are mutually exclusive
      if (cu.ispMode)
      {
        uint32_t nTus = cu.ispMode == HOR_INTRA_SUBPARTITIONS ? cu.lheight() >> Log2(tu.lheight()) : cu.lwidth() >> Log2(tu.lwidth());
        if (subTuCounter == nTus - 1)
        {
          TransformUnit* tuPointer = cu.firstTU;
          for (int tuIdx = 0; tuIdx < subTuCounter; tuIdx++)
          {
            rootCbfSoFar |= TU::getCbfAtDepth(*tuPointer, COMP_Y, trDepth);
            tuPointer = tuPointer->next;
          }
          if (!rootCbfSoFar)
          {
            lastCbfIsInferred = true;
          }
        }
        if (!lastCbfIsInferred)
        {
          previousCbf = TU::getPrevTuCbfAtDepth(tu, COMP_Y, partitioner.currTrDepth);
        }
      }
      if (!lastCbfIsInferred)
      {
        cbf_comp(*tu.cu, TU::getCbfAtDepth(tu, COMP_Y, trDepth), tu.Y(), trDepth, previousCbf, cu.ispMode);
      }
    }
  }
  bool        lumaOnly  = ( cu.chromaFormat == CHROMA_400 || !tu.blocks[COMP_Cb].valid() );
  bool        cbf[3]    = { TU::getCbf( tu, COMP_Y ), chromaCbfs.Cb, chromaCbfs.Cr };
  bool        cbfLuma   = ( cbf[ COMP_Y ] != 0 );
  bool        cbfChroma = false;

  if( !lumaOnly )
  {
    if( tu.blocks[COMP_Cb].valid() )
    {
      cbf   [ COMP_Cb  ] = TU::getCbf( tu, COMP_Cb );
      cbf   [ COMP_Cr  ] = TU::getCbf( tu, COMP_Cr );
    }
    cbfChroma = ( cbf[ COMP_Cb ] || cbf[ COMP_Cr ] );
  }

  if( ( cu.lwidth() > 64 || cu.lheight() > 64 || cbfLuma || cbfChroma ) &&
    (!CU::isSepTree(*tu.cu) || isLuma(tu.chType)) )
  {
    if( cu.cs->pps->useDQP && !cuCtx.isDQPCoded )
    {
      cu_qp_delta(cu, cuCtx.qp, cu.qp);
      cuCtx.qp = cu.qp;
      cuCtx.isDQPCoded = true;
    }
  }
  if (cu.cs->slice->chromaQpAdjEnabled && cbfChroma && !cuCtx.isChromaQpAdjCoded)
  {
    cu_chroma_qp_offset( cu );
    cuCtx.isChromaQpAdjCoded = true;
  }

  if( !lumaOnly )
  {
    joint_cb_cr( tu, ( cbf[COMP_Cb] ? 2 : 0 ) + ( cbf[COMP_Cr] ? 1 : 0 ) );
  }

  if( cbfLuma )
  {
    residual_coding( tu, COMP_Y, &cuCtx );
  }
  if( !lumaOnly )
  {
    for( ComponentID compID = COMP_Cb; compID <= COMP_Cr; compID = ComponentID( compID + 1 ) )
    {
      if( cbf[ compID ] )
      {
        residual_coding( tu, compID, &cuCtx );
      }
    }
  }
}


void CABACWriter::cu_qp_delta( const CodingUnit& cu, int predQP, const int8_t qp )
{
  CHECK(!( predQP != std::numeric_limits<int>::max()), "Unspecified error");
  int       DQp         = qp - predQP;
  int       qpBdOffsetY = cu.cs->sps->qpBDOffset[ CH_L ];
  DQp                   = ( DQp + (MAX_QP + 1) + (MAX_QP + 1) / 2 + qpBdOffsetY + (qpBdOffsetY / 2)) % ((MAX_QP + 1) + qpBdOffsetY) - (MAX_QP + 1) / 2 - (qpBdOffsetY / 2);
  unsigned  absDQP      = unsigned( DQp < 0 ? -DQp : DQp );
  unsigned  unaryDQP    = std::min<unsigned>( absDQP, CU_DQP_TU_CMAX );

  unary_max_symbol( unaryDQP, Ctx::DeltaQP(), Ctx::DeltaQP(1), CU_DQP_TU_CMAX );
  if( absDQP >= CU_DQP_TU_CMAX )
  {
    exp_golomb_eqprob( absDQP - CU_DQP_TU_CMAX, CU_DQP_EG_k );
  }
  if( absDQP > 0 )
  {
    m_BinEncoder.encodeBinEP( DQp < 0 );
  }

  DTRACE_COND( ( isEncoding() ), g_trace_ctx, D_DQP, "x=%d, y=%d, d=%d, pred_qp=%d, DQp=%d, qp=%d\n", cu.blocks[cu.chType].lumaPos().x, cu.blocks[cu.chType].lumaPos().y, cu.qtDepth, predQP, DQp, qp );
}


void CABACWriter::cu_chroma_qp_offset( const CodingUnit& cu )
{
  // cu_chroma_qp_offset_flag
  unsigned qpAdj = cu.chromaQpAdj;
  if( qpAdj == 0 )
  {
    m_BinEncoder.encodeBin( 0, Ctx::ChromaQpAdjFlag() );
  }
  else
  {
    m_BinEncoder.encodeBin( 1, Ctx::ChromaQpAdjFlag() );
    int length = cu.cs->pps->chromaQpOffsetListLen;
    if( length > 1 )
    {
      unary_max_symbol( qpAdj-1, Ctx::ChromaQpAdjIdc(), Ctx::ChromaQpAdjIdc(), length-1 );
    }
  }
}


//================================================================================
//  clause 7.3.8.11
//--------------------------------------------------------------------------------
//    void        residual_coding         ( tu, compID )
//    void        transform_skip_flag     ( tu, compID )
//    void        last_sig_coeff          ( coeffCtx )
//    void        residual_coding_subblock( coeffCtx )
//================================================================================

void CABACWriter::joint_cb_cr( const TransformUnit& tu, const int cbfMask )
{
  if ( !tu.cu->slice->sps->jointCbCr )
  {
    return;
  }

  CHECK( tu.jointCbCr && tu.jointCbCr != cbfMask, "wrong value of jointCbCr (" << (int)tu.jointCbCr << " vs " << (int)cbfMask << ")" );
  if( ( CU::isIntra( *tu.cu ) && cbfMask ) || ( cbfMask == 3 ) )
  {
    m_BinEncoder.encodeBin( tu.jointCbCr ? 1 : 0, Ctx::JointCbCrFlag( cbfMask - 1 ) );
  }
}


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

  if( compID == COMP_Cr && tu.jointCbCr == 3 )
  {
    return;
  }

  ts_flag            ( tu, compID );

  if( tu.mtsIdx[compID] == MTS_SKIP && !tu.cs->slice->tsResidualCodingDisabled )
  {
    residual_codingTS( tu, compID );
    return;
  }

  // determine sign hiding
  bool signHiding  = cu.cs->slice->signDataHidingEnabled;

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

  // determine and set last coeff position and sig group flags
  int                      scanPosLast = tu.lastPos[compID];
  std::bitset<MLS_GRP_NUM> sigGroupFlags;

  for( int subSetId = 0; subSetId <= ( scanPosLast >> cctx.log2CGSize() ); subSetId++ )
  {
    const int scanPosStart = subSetId << cctx.log2CGSize();
    const int scanPosEnd   = scanPosStart + ( 1 << cctx.log2CGSize() ) - 1;

    for( int scanPos = scanPosEnd; scanPos >= scanPosStart; scanPos-- )
    {
      unsigned blkPos = cctx.blockPos( scanPos );

      if( coeff[blkPos] )
      {
        sigGroupFlags.set( subSetId );
        break;
      }
    }
  }
  CHECK( scanPosLast < 0, "Coefficient coding called for empty TU" );
  cctx.setScanPosLast(scanPosLast);

  if( cuCtx && tu.mtsIdx[compID] != 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;
  }
  if( cuCtx && tu.mtsIdx[compID] != MTS_SKIP && tu.blocks[ compID ].height >= 4 && tu.blocks[ compID ].width >= 4 )
  {
    const int lfnstLastScanPosTh = isLuma( compID ) ? LFNST_LAST_SIG_LUMA : LFNST_LAST_SIG_CHROMA;
    cuCtx->lfnstLastScanPos |= cctx.scanPosLast() >= lfnstLastScanPosTh;
  }
  if (cuCtx && isLuma(compID) && tu.mtsIdx[compID] != MTS_SKIP)
  {
    cuCtx->mtsLastScanPos |= cctx.scanPosLast() >= 1;
  }
  
  // code last coeff position
  last_sig_coeff( cctx, tu, compID );

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

  int ctxBinSampleRatio = MAX_TU_LEVEL_CTX_CODED_BIN_CONSTRAINT;
  cctx.remRegBins = (tu.getTbAreaAfterCoefZeroOut(compID) * ctxBinSampleRatio) >> 4;

  const bool zeroOutCheck  = isLuma( compID ) && tu.cs->sps->MTS && tu.cu->sbtInfo != 0 && tu.blocks[compID].height <= 32 && tu.blocks[compID].width <= 32;
  const bool zeroOutWidth  = tu.blocks[compID].width;
  const bool zeroOutHeight = tu.blocks[compID].height;

  for( int subSetId = ( cctx.scanPosLast() >> cctx.log2CGSize() ); subSetId >= 0; subSetId--)
  {
    cctx.initSubblock( subSetId, sigGroupFlags[subSetId] );

    if( zeroOutCheck )
    {
      if( ( zeroOutHeight && cctx.cgPosY() >= ( 16 >> cctx.log2CGHeight() ) ) || ( zeroOutWidth  && cctx.cgPosX() >= ( 16 >> cctx.log2CGWidth() ) ) )
      {
        continue;
      }
    }

    residual_coding_subblock( cctx, coeff, stateTab, state );
    if ( cuCtx && isLuma(compID) && cctx.isSigGroup() && ( cctx.cgPosY() > 3 || cctx.cgPosX() > 3 ) )
    {
      cuCtx->violatesMtsCoeffConstraint = true;
    }
  }
}


void CABACWriter::ts_flag( const TransformUnit& tu, ComponentID compID )
{
  int tsFlag = tu.mtsIdx[compID] == MTS_SKIP ? 1 : 0;
  int ctxIdx = isLuma(compID) ? 0 : 1;
  
  if( TU::isTSAllowed ( tu, compID ) )
  {
    m_BinEncoder.encodeBin( tsFlag, Ctx::TransformSkipFlag(ctxIdx));
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "ts_flag() etype=%d pos=(%d,%d) mtsIdx=%d\n", COMP_Y, tu.cu->lx(), tu.cu->ly(), tsFlag );
}


void CABACWriter::mts_idx( const CodingUnit& cu, CUCtx* cuCtx )
{
  TransformUnit &tu = *cu.firstTU;
  int        mtsIdx = tu.mtsIdx[COMP_Y];
  
  if( CU::isMTSAllowed( cu, COMP_Y ) && cuCtx && !cuCtx->violatesMtsCoeffConstraint &&
      cuCtx->mtsLastScanPos && cu.lfnstIdx == 0 && mtsIdx != MTS_SKIP)
  {
    int symbol = mtsIdx != MTS_DCT2_DCT2 ? 1 : 0;
    int ctxIdx = 0;
    
    m_BinEncoder.encodeBin( symbol, Ctx::MTSIdx(ctxIdx));
    
    if( symbol )
    {
      ctxIdx = 1;
      for( int i = 0; i < 3; i++, ctxIdx++ )
      {
        symbol = mtsIdx > i + MTS_DST7_DST7 ? 1 : 0;
        m_BinEncoder.encodeBin( symbol, Ctx::MTSIdx(ctxIdx));
        
        if( !symbol )
        {
          break;
        }
      }
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "mts_idx() etype=%d pos=(%d,%d) mtsIdx=%d\n", COMP_Y, tu.cu->lx(), tu.cu->ly(), mtsIdx);
}


void CABACWriter::isp_mode( const CodingUnit& cu )
{
  if( !CU::isIntra( cu ) || !isLuma( cu.chType ) || cu.multiRefIdx || !cu.cs->sps->ISP || cu.bdpcmM[CH_L] || !CU::canUseISP( cu, getFirstComponentOfChannel( cu.chType ) )  || cu.colorTransform)
  {
    CHECK( cu.ispMode != NOT_INTRA_SUBPARTITIONS, "cu.ispMode != 0" );
    return;
  }
  if ( cu.ispMode == NOT_INTRA_SUBPARTITIONS )
  {
    m_BinEncoder.encodeBin( 0, Ctx::ISPMode( 0 ) );
  }
  else
  {
    m_BinEncoder.encodeBin( 1, Ctx::ISPMode( 0 ) );
    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::residual_lfnst_mode( const CodingUnit& cu, CUCtx& cuCtx )
{
  int chIdx = CS::isDualITree( *cu.cs ) && cu.chType == CH_C ? 1 : 0;
  if( ( cu.ispMode && !CU::canUseLfnstWithISP( cu, cu.chType ) ) ||
      (cu.cs->sps->LFNST && CU::isIntra(cu) && cu.mipFlag && !allowLfnstWithMip(cu.lumaSize())) ||
    ( CU::isSepTree(cu) && cu.chType == CH_C && std::min( cu.blocks[ 1 ].width, cu.blocks[ 1 ].height ) < 4 )
    || ( cu.blocks[ chIdx ].lumaSize().width > cu.cs->sps->getMaxTbSize() || cu.blocks[ chIdx ].lumaSize().height > cu.cs->sps->getMaxTbSize() )
    )
  {
    return;
  }

  if( cu.cs->sps->LFNST && CU::isIntra( cu )  )
  {
    const bool lumaFlag                   = CU::isSepTree(cu) ? (   isLuma( cu.chType ) ? true : false ) : true;
    const bool chromaFlag                 = CU::isSepTree(cu) ? ( isChroma( cu.chType ) ? true : false ) : true;
          bool nonZeroCoeffNonTsCorner8x8 = ( lumaFlag && cuCtx.violatesLfnstConstrained[CH_L] ) || (chromaFlag && cuCtx.violatesLfnstConstrained[CH_C] );

    bool isTrSkip = false;

    for( const auto& currTU : cTUTraverser( cu.firstTU, cu.lastTU->next ) )
    {
      const uint32_t numValidComp = getNumberValidComponents(cu.chromaFormat);
      for (uint32_t compID = COMP_Y; compID < numValidComp; compID++)
      {
        if (currTU.blocks[compID].valid() && TU::getCbf(currTU, (ComponentID)compID) && currTU.mtsIdx[compID] == MTS_SKIP)
        {
          isTrSkip = true;
          break;
        }
      }
    }

    if( (!cuCtx.lfnstLastScanPos && !cu.ispMode) || nonZeroCoeffNonTsCorner8x8 || isTrSkip )
    {
      return;
    }
  }
  else
  {
    return;
  }
  
  unsigned cctx = 0;
  if ( CU::isSepTree(cu) ) cctx++;

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

  if( idxLFNST )
  {
    m_BinEncoder.encodeBin( (idxLFNST - 1) ? 1 : 0, Ctx::LFNSTIdx(2));
  }

  DTRACE( g_trace_ctx, D_SYNTAX, "residual_lfnst_mode() etype=%d pos=(%d,%d) mode=%d\n", COMP_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.cs->sps->MTS && tu.cu->sbtInfo != 0 && tu.blocks[ compID ].width <= 32 && tu.blocks[ compID ].height <= 32 && compID == COMP_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 );
    }
  }
}


namespace
{
  // Estimates the bits of bins exactly like BitEstimator (same context updates, same bits per bin; keep the two in
  // sync), but sums them in its own member. As a local object whose address never escapes, its sum can stay in a
  // register, while BitEstimator's sum is read and written in memory for every bin.
  class LocalBitEstimate
  {
  public:
    explicit LocalBitEstimate( CtxStore& ctx ) : m_ctx( ctx ) {}

    void encodeBin     ( unsigned bin, unsigned ctxId )        { m_ctx[ctxId].estFracBitsUpdate( bin, m_fracBits ); }
    void encodeBinsEP  ( unsigned /*bins*/, unsigned numBins ) { m_fracBits += BinProbModelBase::estFracBitsEP( numBins ); }
    void encodeRemAbsEP( unsigned bins, unsigned goRicePar, unsigned cutoff, int maxLog2TrDynamicRange )
    {
      m_fracBits += BinProbModelBase::estFracBitsEP( BitEstimatorBase::numRemAbsEPBins( bins, goRicePar, cutoff, maxLog2TrDynamicRange ) );
    }

    uint64_t fracBits() const { return m_fracBits; }

  private:
    CtxStore& m_ctx;
    uint64_t  m_fracBits = 0;
  };

// CABACWriter::residual_coding_subblock with the bins coded by binCoder: the writer's BinEncIf, or a LocalBitEstimate
template<class BinCoder>
void residual_coding_subblock_bins( CoeffCodingContext& cctx, const TCoeffSig* coeff, const int stateTransTable, int& state, BinCoder& binCoder )
{
  //===== 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() )
    {
      binCoder.encodeBin( 1, cctx.sigGroupCtxId() );
    }
    else
    {
      binCoder.encodeBin( 0, cctx.sigGroupCtxId() );
      return;
    }
  }

  //===== 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;
  int       remRegBins    = cctx.remRegBins;
  int       firstPosMode2 = minSubPos - 1;

  for( ; nextSigPos >= minSubPos && remRegBins >= 4; nextSigPos-- )
  {
    const int blkPos     = cctx.blockPos( nextSigPos );
    TCoeff    Coeff      = coeff[ blkPos ];
    unsigned  sigFlag    = ( Coeff != 0 );
    if( numNonZero || nextSigPos != inferSigPos )
    {
      const unsigned sigCtxId = cctx.sigCtxIdAbsWithAcc( nextSigPos, state );
      binCoder.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.sigCtxIdAbsWithAcc( nextSigPos, state ); // required for setting variables that are needed for gtx/par context selection
    }

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

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

      unsigned gt1 = !!remAbsLevel;
      binCoder.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;
        binCoder.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;
        binCoder.encodeBin(gt2, cctx.greater2CtxIdAbs(ctxOff));
        DTRACE(g_trace_ctx, D_SYNTAX_RESI, "gt2_flag() bin=%d ctx=%d\n", gt2, cctx.greater2CtxIdAbs(ctxOff));
        remRegBins--;
      }

      cctx.absVal1stPass( nextSigPos, std::min<TCoeff>( 4 + ( absLevel & 1 ), absLevel ) );
    }

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


  //===== 2nd PASS: Go-rice codes =====
  for( int scanPos = firstSigPos; scanPos > firstPosMode2; scanPos-- )
  {
    unsigned absLevel = abs( coeff[cctx.blockPos( scanPos )] );

    if( absLevel >= 4 )
    {
      int      sumAll   = cctx.templateAbsSum( scanPos, coeff, 4 );
      unsigned ricePar  = g_auiGoRiceParsCoeff[sumAll];
      unsigned rem      = ( absLevel - 4 ) >> 1;
      binCoder.encodeRemAbsEP( rem, ricePar, COEF_REMAIN_BIN_REDUCTION, 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(state, rice);
    unsigned  rem       = ( absLevel == 0 ? pos0 : absLevel <= pos0 ? absLevel-1 : absLevel );
    binCoder.encodeRemAbsEP( rem, rice, COEF_REMAIN_BIN_REDUCTION, 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++;
      firstNZPos = scanPos;
      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;
  }
  binCoder.encodeBinsEP( signPattern, numSigns );
}
}   // namespace

void CABACWriter::residual_coding_subblock( CoeffCodingContext& cctx, const TCoeffSig* coeff, const int stateTransTable, int& state )
{
  if( m_BinEncoder.isEncoding() )
  {
    residual_coding_subblock_bins( cctx, coeff, stateTransTable, state, m_BinEncoder );
  }
  else
  {
    // only estimating bits (m_BinEncoder is a BitEstimator): sum the subblock's bits locally, add them once
    LocalBitEstimate estimate( static_cast<CtxStore&>( m_BinEncoder.getCtx() ) );
    residual_coding_subblock_bins( cctx, coeff, stateTransTable, state, estimate );
    static_cast<BitEstimatorBase&>( m_BinEncoder ).addEstFracBits( estimate.fracBits() );
  }
}


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->bdpcmM[toChannelType(compID)] );
  const TCoeffSig*    coeff   = tu.getCoeffs( compID ).buf;
  int maxCtxBins = (cctx.maxNumCoeff() * 7) >> 2;
  cctx.remRegBins = maxCtxBins;

  // 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 TCoeffSig* 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() )
    {
        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.encodeBin( 0, cctx.sigGroupCtxId( true ) );
        DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_sigGroup() bin=%d ctx=%d\n", 0, cctx.sigGroupCtxId() );
      return;
    }
  }

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

  int rightPixel, belowPixel, modAbsCoeff;

  int lastScanPosPass1 = -1;
  int lastScanPosPass2 = -1;
  for (; nextSigPos <= minSubPos && cctx.remRegBins >= 4; nextSigPos++)
  {
    TCoeff    Coeff      = coeff[ cctx.blockPos( nextSigPos ) ];
    unsigned  sigFlag    = ( Coeff != 0 );
    if( numNonZero || nextSigPos != inferSigPos )
    {
      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 );
      cctx.remRegBins--;
    }

    if( sigFlag )
    {
      //===== encode sign's =====
      int sign = Coeff < 0;
      const unsigned signCtxId = cctx.signCtxIdAbsTS(nextSigPos, coeff, cctx.bdpcm());
      m_BinEncoder.encodeBin(sign, signCtxId);
      cctx.remRegBins--;
      numNonZero++;
      cctx.neighTS(rightPixel, belowPixel, nextSigPos, coeff);
      modAbsCoeff = cctx.deriveModCoeff(rightPixel, belowPixel, abs(Coeff), cctx.bdpcm());
      remAbsLevel = modAbsCoeff - 1;

      unsigned gt1 = !!remAbsLevel;
      const unsigned gt1CtxId = cctx.lrg1CtxIdAbsTS(nextSigPos, coeff, cctx.bdpcm());
      m_BinEncoder.encodeBin(gt1, gt1CtxId);
      DTRACE(g_trace_ctx, D_SYNTAX_RESI, "ts_gt1_flag() bin=%d ctx=%d\n", gt1, gt1CtxId);
      cctx.remRegBins--;

      if( gt1 )
      {
        remAbsLevel  -= 1;
        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() );
        cctx.remRegBins--;
      }
    }
    lastScanPosPass1 = nextSigPos;
  }

  int cutoffVal = 2;
  int numGtBins = 4;

  for (int scanPos = firstSigPos; scanPos <= minSubPos && cctx.remRegBins >= 4; scanPos++)
  {
    unsigned absLevel;
    cctx.neighTS(rightPixel, belowPixel, scanPos, coeff);
    absLevel = cctx.deriveModCoeff(rightPixel, belowPixel, abs(coeff[cctx.blockPos(scanPos)]), cctx.bdpcm());
    cutoffVal = 2;
    for (int i = 0; i < numGtBins; i++)
    {
      if (absLevel >= cutoffVal)
      {
        unsigned gt2 = (absLevel >= (cutoffVal + 2));
        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, std::min<int>(absLevel, cutoffVal + 2));
        cctx.remRegBins--;
      }
      cutoffVal += 2;
    }
    lastScanPosPass2 = scanPos;
  }

  //===== coeff bypass ====
  for( int scanPos = firstSigPos; scanPos <= minSubPos; scanPos++ )
  {
    unsigned absLevel;
    cctx.neighTS(rightPixel, belowPixel, scanPos, coeff);
    cutoffVal = (scanPos <= lastScanPosPass2 ? 10 : (scanPos <= lastScanPosPass1 ? 2 : 0));
    absLevel = cctx.deriveModCoeff(rightPixel, belowPixel, abs(coeff[cctx.blockPos(scanPos)]), cctx.bdpcm()||!cutoffVal);
    if( absLevel >= cutoffVal )
    {
      //int       rice = cctx.templateAbsSumTS( scanPos, coeff );
      int       rice = 1;
      unsigned  rem = scanPos <= lastScanPosPass1 ? (absLevel - cutoffVal) >> 1 : absLevel;
      m_BinEncoder.encodeRemAbsEP( rem, rice, COEF_REMAIN_BIN_REDUCTION, cctx.maxLog2TrDRange() );
      DTRACE( g_trace_ctx, D_SYNTAX_RESI, "ts_rem_val() bin=%d ctx=%d sp=%d\n", rem, rice, scanPos );

      if (absLevel && scanPos > lastScanPosPass1)
      {
        int sign = coeff[cctx.blockPos(scanPos)] < 0;
        m_BinEncoder.encodeBinEP(sign);
      }
    }
  }
}


//================================================================================
//  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::codeAlfCtuEnabled( CodingStructure& cs, ChannelType channel, AlfParam* alfParam, const int numCtus )
{
  if( isLuma( channel ) )
  {
    if (alfParam->alfEnabled[COMP_Y])
      codeAlfCtuEnabled( cs, COMP_Y, alfParam, numCtus );
  }
  else
  {
    if (alfParam->alfEnabled[COMP_Cb])
      codeAlfCtuEnabled( cs, COMP_Cb, alfParam, numCtus );
    if (alfParam->alfEnabled[COMP_Cr])
      codeAlfCtuEnabled( cs, COMP_Cr, alfParam, numCtus );
  }
}


void CABACWriter::codeAlfCtuEnabled( CodingStructure& cs, ComponentID compID, AlfParam* alfParam, const int numCtus )
{
  for( int ctuIdx = 0; ctuIdx < numCtus; ctuIdx++ )
  {
    codeAlfCtuEnabledFlag( cs, ctuIdx, compID );
  }
}


void CABACWriter::codeAlfCtuEnabledFlag( CodingStructure& cs, uint32_t ctuRsAddr, const int compIdx)
{
  CHECKD( !cs.sps->alfEnabled, "ALF is disabled in SPS" ); 

  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->maxCUSize, ry * cs.pcv->maxCUSize );
  const uint32_t      curSliceIdx = cs.slice->independentSliceIdx;
  const uint32_t      curTileIdx  = cs.pps->getTileIdx( pos );
  bool                leftAvail   = cs.getCURestricted( pos.offset( -(int)pcv.maxCUSize, 0 ), pos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;
  bool                aboveAvail  = cs.getCURestricted( pos.offset( 0, -(int)pcv.maxCUSize ), pos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;

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

  const uint8_t* ctbAlfFlag = cs.slice->pic->m_alfCtuEnabled[ compIdx ].data();
  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::codeCcAlfFilterControlIdc(uint8_t idcVal, CodingStructure &cs, const ComponentID compID,
                                            const int curIdx, const uint8_t *filterControlIdc, Position lumaPos,
                                            const int filterCount)
{
  CHECK(idcVal > filterCount, "Filter index is too large");

  const uint32_t curSliceIdx    = cs.slice->independentSliceIdx;
  const uint32_t curTileIdx     = cs.pps->getTileIdx( lumaPos );
  Position       leftLumaPos    = lumaPos.offset(-(int)cs.pcv->maxCUSize, 0);
  Position       aboveLumaPos   = lumaPos.offset(0, -(int)cs.pcv->maxCUSize);
  bool           leftAvail      = cs.getCURestricted( leftLumaPos,  lumaPos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;
  bool           aboveAvail     = cs.getCURestricted( aboveLumaPos, lumaPos, curSliceIdx, curTileIdx, CH_L, TREE_D ) ? true : false;
  int            ctxt           = 0;

  if (leftAvail)
  {
    ctxt += ( filterControlIdc[curIdx - 1]) ? 1 : 0;
  }
  if (aboveAvail)
  {
    ctxt += (filterControlIdc[curIdx - cs.pcv->widthInCtus]) ? 1 : 0;
  }
  ctxt += ( compID == COMP_Cr ) ? 3 : 0;

  m_BinEncoder.encodeBin( ( idcVal == 0 ) ? 0 : 1, Ctx::CcAlfFilterControlFlag( ctxt ) ); // ON/OFF flag is context coded
  if ( idcVal > 0 )
  {
    int val = (idcVal - 1);
    while ( val )
    {
      m_BinEncoder.encodeBinEP( 1 );
      val--;
    }
    if ( idcVal < filterCount )
    {
      m_BinEncoder.encodeBinEP( 0 );
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "ccAlfFilterControlIdc() compID=%d pos=(%d,%d) ctxt=%d, filterCount=%d, idcVal=%d\n", compID, lumaPos.x, lumaPos.y, ctxt, filterCount, idcVal );
}


void CABACWriter::mip_flag( const CodingUnit& cu )
{
  if( !cu.Y().valid() )
  {
    return;
  }
  if( !cu.cs->sps->MIP )
  {
    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;
  }

  mip_pred_mode( cu );
}


void CABACWriter::mip_pred_mode( const CodingUnit& cu )
{
  m_BinEncoder.encodeBinEP( (cu.mipTransposedFlag ? 1 : 0) );

  const int numModes = getNumModesMip( cu.Y() );
  CHECKD( cu.intraDir[CH_L] < 0 || cu.intraDir[CH_L] >= numModes, "Invalid MIP mode" );
  xWriteTruncBinCode( cu.intraDir[CH_L], numModes );

  DTRACE( g_trace_ctx, D_SYNTAX, "mip_pred_mode() pos=(%d,%d) mode=%d transposed=%d\n", cu.lumaPos().x, cu.lumaPos().y, cu.intraDir[CH_L], cu.mipTransposedFlag ? 1 : 0 );
}


void CABACWriter::codeAlfCtuFilterIndex(CodingStructure& cs, uint32_t ctuRsAddr)
{
  const uint8_t* ctbAlfFlag = cs.slice->pic->m_alfCtuEnabled[ COMP_Y ].data();
  if (!ctbAlfFlag[ctuRsAddr])
  {
    return;
  }

  const short* alfCtbFilterIndex = cs.slice->pic->m_alfCtbFilterIndex.data();
  const unsigned filterSetIdx = alfCtbFilterIndex[ctuRsAddr];
  unsigned numAps = cs.slice->numAps;
  unsigned numAvailableFiltSets = numAps + NUM_FIXED_FILTER_SETS;
  if (numAvailableFiltSets > NUM_FIXED_FILTER_SETS)
  {
    int useTemporalFilt = (filterSetIdx >= NUM_FIXED_FILTER_SETS) ? 1 : 0;
    m_BinEncoder.encodeBin(useTemporalFilt, Ctx::AlfUseTemporalFilt());
    if (useTemporalFilt)
    {
      CHECK((filterSetIdx - NUM_FIXED_FILTER_SETS) >= (numAvailableFiltSets - NUM_FIXED_FILTER_SETS), "temporal non-latest set");
      if (numAps > 1)
      {
        xWriteTruncBinCode(filterSetIdx - NUM_FIXED_FILTER_SETS, numAvailableFiltSets - NUM_FIXED_FILTER_SETS);
      }
    }
    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);
  }
}


void CABACWriter::codeAlfCtuAlternatives( CodingStructure& cs, ChannelType channel, AlfParam* alfParam, const int numCtus )
{
  if( isChroma( channel ) )
  {
    if (alfParam->alfEnabled[COMP_Cb])
      codeAlfCtuAlternatives( cs, COMP_Cb, alfParam, numCtus );
    if (alfParam->alfEnabled[COMP_Cr])
      codeAlfCtuAlternatives( cs, COMP_Cr, alfParam, numCtus );
  }
}


void CABACWriter::codeAlfCtuAlternatives( CodingStructure& cs, ComponentID compID, AlfParam* alfParam, const int numCtus)
{
  if( compID == COMP_Y )
    return;
  const uint8_t* ctbAlfFlag = cs.slice->pic->m_alfCtuEnabled[ compID ].data();

  for( int ctuIdx = 0; ctuIdx < numCtus; ctuIdx++ )
  {
    if( ctbAlfFlag[ctuIdx] )
    {
      codeAlfCtuAlternative( cs, ctuIdx, compID, alfParam );
    }
  }
}


void CABACWriter::codeAlfCtuAlternative( CodingStructure& cs, uint32_t ctuRsAddr, const int compIdx, const AlfParam* alfParam)
{
  if( compIdx == COMP_Y )
    return;

  {
    const uint8_t* ctbAlfFlag = cs.slice->pic->m_alfCtuEnabled[ compIdx ].data();

    if( ctbAlfFlag[ctuRsAddr] )
    {
      const int numAlts = alfParam->numAlternativesChroma;
      const uint8_t* ctbAlfAlternative = cs.slice->pic->m_alfCtuAlternative[compIdx].data();
      unsigned numOnes = ctbAlfAlternative[ctuRsAddr];
      assert( ctbAlfAlternative[ctuRsAddr] < numAlts );
      for( int i = 0; i < numOnes; ++i )
        m_BinEncoder.encodeBin( 1, Ctx::ctbAlfAlternative( compIdx-1 ) );
      if( numOnes < numAlts-1 )
        m_BinEncoder.encodeBin( 0, Ctx::ctbAlfAlternative( compIdx-1 ) );
    }
  }
}

} // namespace vvenc

//! \}


Coverage Report

Created: 2026-10-17 06:56