CABACWriter.cpp

    unsigned&  ipred_mode = ipred_modes[k];

    PU::getIntraMPMs( *pu, mpm_pred );

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

    pu = pu->next;
  }

  pu = cu.firstPU;

  // mpm_idx / rem_intra_luma_pred_mode
  for( int k = 0; k < numBlocks; k++ )
  {
    const unsigned& mpm_idx = mpm_idxs[k];
    if( mpm_idx < numMPMs )
    {
      {
        m_BinEncoder.encodeBinEP( mpm_idx > 0 );
        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
    {
      unsigned* mpm_pred   = mpm_preds[k];
      unsigned  ipred_mode = ipred_modes[k];

      // 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", k, pu->lumaPos().x, pu->lumaPos().y, pu->intraDir[0] );
    pu = pu->next;
  }
}


void CABACWriter::intra_luma_pred_mode( const PredictionUnit& pu )
{

  // prev_intra_luma_pred_flag
  const int numMPMs  = NUM_MOST_PROBABLE_MODES;
  unsigned  mpm_pred[numMPMs];
  
  PU::getIntraMPMs( pu, mpm_pred );

  unsigned ipred_mode = pu.intraDir[0];
  unsigned mpm_idx = numMPMs;

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

  // mpm_idx / rem_intra_luma_pred_mode
  if( mpm_idx < numMPMs )
  {
    {
      m_BinEncoder.encodeBinEP( mpm_idx > 0 );
      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
  {
    std::sort( mpm_pred, 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 || ( CS::isDualITree( *cu.cs ) && cu.chType == CHANNEL_TYPE_LUMA ) )
  {
    return;
  }

  const PredictionUnit* pu = cu.firstPU;

  intra_chroma_pred_mode( *pu );
}

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

    unary_max_symbol( symbol, Ctx::IPredMode[1]( 2 ), Ctx::IPredMode[1]( 3 ), maxSymbol - 1 );
}


void CABACWriter::intra_chroma_pred_mode( const PredictionUnit& pu )
{
  const unsigned intraDir = pu.intraDir[1];
  {
    if( intraDir == DM_CHROMA_IDX )
    {
      m_BinEncoder.encodeBin( 0, Ctx::IPredMode[1]( 1 ) );
      return;
    }
    m_BinEncoder.encodeBin( 1, Ctx::IPredMode[1]( 1 ) );
  }

  // LM chroma mode
  if( pu.cs->sps->getSpsNext().getUseLMChroma() )
  {
    intra_chroma_lmc_mode( pu );
    if ( PU::isLMCMode( intraDir ) )
    {
      return;
    }
  }

  // chroma candidate index
  unsigned chromaCandModes[ NUM_CHROMA_MODE ];
  PU::getIntraChromaCandModes( pu, 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::isInter( cu ) )
  {
    PredictionUnit& pu = *cu.firstPU;
    if( !pu.mergeFlag )
    {
      rqt_root_cbf( cu );
    }

    if( !cu.rootCbf )
    {
      return;
    }
  }


  ChromaCbfs chromaCbfs;
  transform_tree( *cu.cs, partitioner, cuCtx, chromaCbfs );
}

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::end_of_ctu( const CodingUnit& cu, CUCtx& cuCtx )
{
  const Slice*  slice             = cu.cs->slice;
#if HEVC_TILES_WPP
  const TileMap& tileMap          = *cu.cs->picture->tileMap;
  const int     currentCTUTsAddr  = tileMap.getCtuRsToTsAddrMap( CU::getCtuAddr( cu ) );
#else
  const int     currentCTUTsAddr  = CU::getCtuAddr( cu );
#endif
  const bool    isLastSubCUOfCtu  = CU::isLastSubCUOfCtu( cu );

  if ( isLastSubCUOfCtu
    && ( !CS::isDualITree( *cu.cs ) || cu.chromaFormat == CHROMA_400 || isChroma( cu.chType ) )
      )
  {
    cuCtx.isDQPCoded = ( cu.cs->pps->getUseDQP() && !cuCtx.isDQPCoded );

    // The 1-terminating bit is added to all streams, so don't add it here when it's 1.
    // i.e. when the slice segment CurEnd CTU address is the current CTU address+1.
#if HEVC_DEPENDENT_SLICES
    if( slice->getSliceSegmentCurEndCtuTsAddr() != currentCTUTsAddr + 1 )
#else
    if(slice->getSliceCurEndCtuTsAddr() != currentCTUTsAddr + 1)
#endif
    {
      m_BinEncoder.encodeBinTrm( 0 );
    }
  }
}





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

void CABACWriter::prediction_unit( const PredictionUnit& pu )
{
#if ENABLE_SPLIT_PARALLELISM || ENABLE_WPP_PARALLELISM
  CHECK( pu.cacheUsed, "Processing a PU that should be in cache!" );
  CHECK( pu.cu->cacheUsed, "Processing a CU that should be in cache!" );

#endif
  if( pu.cu->skip )
  {
    CHECK( !pu.mergeFlag, "merge_flag must be true for skipped CUs" );
  }
  else
  {
    merge_flag( pu );
  }
  if( pu.mergeFlag )
  {
    subblock_merge_flag( *pu.cu );
    MHIntra_flag( pu );
    if ( pu.mhIntraFlag )
    {
      MHIntra_luma_pred_modes( *pu.cu );
    }
    triangle_mode( *pu.cu );
    if (pu.mmvdMergeFlag)
    {
      mmvd_merge_idx(pu);
    }
    else
    merge_idx    ( pu );
  }
  else
  {
    inter_pred_idc( pu );
    affine_flag   ( *pu.cu );
#if JVET_M0444_SMVD
    smvd_mode( pu );
#endif
    if( pu.interDir != 2 /* PRED_L1 */ )
    {
      ref_idx     ( pu, REF_PIC_LIST_0 );
      if ( pu.cu->affine )
      {
        mvd_coding(pu.mvdAffi[REF_PIC_LIST_0][0], 0);
        mvd_coding(pu.mvdAffi[REF_PIC_LIST_0][1], 0);
        if ( pu.cu->affineType == AFFINEMODEL_6PARAM )
        {
          mvd_coding(pu.mvdAffi[REF_PIC_LIST_0][2], 0);
        }
      }
      else
      {
        mvd_coding( pu.mvd[REF_PIC_LIST_0], pu.cu->imv );
      }
      mvp_flag    ( pu, REF_PIC_LIST_0 );
    }
    if( pu.interDir != 1 /* PRED_L0 */ )
    {
#if JVET_M0444_SMVD
      if ( pu.cu->smvdMode != 1 )
      {
#endif
      ref_idx     ( pu, REF_PIC_LIST_1 );
      if( !pu.cs->slice->getMvdL1ZeroFlag() || pu.interDir != 3 /* PRED_BI */ )
      {
        if ( pu.cu->affine )
        {
          mvd_coding(pu.mvdAffi[REF_PIC_LIST_1][0], 0);
          mvd_coding(pu.mvdAffi[REF_PIC_LIST_1][1], 0);
          if ( pu.cu->affineType == AFFINEMODEL_6PARAM )
          {
            mvd_coding(pu.mvdAffi[REF_PIC_LIST_1][2], 0);
          }
        }
        else
        {
          mvd_coding( pu.mvd[REF_PIC_LIST_1], pu.cu->imv );
        }
      }
#if JVET_M0444_SMVD
      }
#endif
      mvp_flag    ( pu, REF_PIC_LIST_1 );
    }
  }
}

#if JVET_M0444_SMVD
void CABACWriter::smvd_mode( const PredictionUnit& pu )
{
  if ( pu.interDir != 3 || pu.cu->affine )
  {
    return;
  }

  if ( pu.cs->slice->getBiDirPred() == false )
  {
    return;
  }

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

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

void CABACWriter::subblock_merge_flag( const CodingUnit& cu )
{
  if ( cu.firstPU->mergeFlag && (cu.firstPU->mmvdMergeFlag || cu.mmvdSkip) )
  {
    return;
  }

  if ( !cu.cs->slice->isIntra() && (cu.cs->sps->getSpsNext().getUseAffine() || cu.cs->sps->getSBTMVPEnabledFlag()) && cu.lumaSize().width >= 8 && cu.lumaSize().height >= 8 )
  {
    unsigned ctxId = DeriveCtx::CtxAffineFlag( cu );
    m_BinEncoder.encodeBin( cu.affine, Ctx::AffineFlag( 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->getSpsNext().getUseAffine() && cu.lumaSize().width > 8 && cu.lumaSize().height > 8 )
  {
    unsigned ctxId = DeriveCtx::CtxAffineFlag( cu );
    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->getSpsNext().getUseAffineType() )
    {
      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 PredictionUnit& pu )
{
  m_BinEncoder.encodeBin( pu.mergeFlag, Ctx::MergeFlag() );

  DTRACE( g_trace_ctx, D_SYNTAX, "merge_flag() merge=%d pos=(%d,%d) size=%dx%d\n", pu.mergeFlag ? 1 : 0, pu.lumaPos().x, pu.lumaPos().y, pu.lumaSize().width, pu.lumaSize().height );
  if (pu.mergeFlag)
  {
    m_BinEncoder.encodeBin(pu.mmvdMergeFlag, Ctx::MmvdFlag(0));
    DTRACE(g_trace_ctx, D_SYNTAX, "mmvd_merge_flag() mmvd_merge=%d pos=(%d,%d) size=%dx%d\n", pu.mmvdMergeFlag ? 1 : 0, pu.lumaPos().x, pu.lumaPos().y, pu.lumaSize().width, pu.lumaSize().height);
  }
}

void CABACWriter::imv_mode( const CodingUnit& cu )
{
  const SPSNext& spsNext = cu.cs->sps->getSpsNext();

  if( !spsNext.getUseIMV() )
  {
    return;
  }

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

  unsigned ctxId = DeriveCtx::CtxIMVFlag( cu );
  if (!(cu.firstPU->interDir == 1 && cu.cs->slice->getRefPic(REF_PIC_LIST_0, cu.firstPU->refIdx[REF_PIC_LIST_0])->getPOC() == cu.cs->slice->getPOC())) // the first bin of IMV flag does need to be signaled in IBC block
    m_BinEncoder.encodeBin( ( cu.imv > 0 ), Ctx::ImvFlag( ctxId ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "imv_mode() value=%d ctx=%d\n", (cu.imv > 0), ctxId );

  if( spsNext.getImvMode() == IMV_4PEL && cu.imv > 0 )
  {
    m_BinEncoder.encodeBin( ( cu.imv > 1 ), Ctx::ImvFlag( 3 ) );
    DTRACE( g_trace_ctx, D_SYNTAX, "imv_mode() value=%d ctx=%d\n", ( cu.imv > 1 ), 3 );
  }

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

void CABACWriter::merge_idx( const PredictionUnit& pu )
{

  if ( pu.cu->affine )
  {
    int numCandminus1 = int( pu.cs->slice->getMaxNumAffineMergeCand() ) - 1;
    if ( numCandminus1 > 0 )
    {
      if ( pu.mergeIdx == 0 )
      {
        m_BinEncoder.encodeBin( 0, Ctx::AffMergeIdx() );
        DTRACE( g_trace_ctx, D_SYNTAX, "aff_merge_idx() aff_merge_idx=%d\n", pu.mergeIdx );
        return;
      }
      else
      {
#if !JVET_M0381_ONE_CTX_FOR_SUBBLOCK_MRG_IDX
        bool useExtCtx = pu.cs->sps->getSBTMVPEnabledFlag();
#endif
        m_BinEncoder.encodeBin( 1, Ctx::AffMergeIdx() );
        for ( unsigned idx = 1; idx < numCandminus1; idx++ )
        {
#if !JVET_M0381_ONE_CTX_FOR_SUBBLOCK_MRG_IDX
          if ( useExtCtx )
          {
            m_BinEncoder.encodeBin( pu.mergeIdx == idx ? 0 : 1, Ctx::AffMergeIdx( std::min<int>( idx, NUM_MERGE_IDX_EXT_CTX - 1 ) ) );
          }
          else
          {
#endif
            m_BinEncoder.encodeBinEP( pu.mergeIdx == idx ? 0 : 1 );
#if !JVET_M0381_ONE_CTX_FOR_SUBBLOCK_MRG_IDX
          }
#endif
          if ( pu.mergeIdx == idx )
          {
            break;
          }
        }
      }
    }
    DTRACE( g_trace_ctx, D_SYNTAX, "aff_merge_idx() aff_merge_idx=%d\n", pu.mergeIdx );
  }
  else
  {
    if( pu.cu->triangle )
    {
#if JVET_M0883_TRIANGLE_SIGNALING
      bool    splitDir = pu.triangleSplitDir;
      uint8_t candIdx0 = pu.triangleMergeIdx0;
      uint8_t candIdx1 = pu.triangleMergeIdx1;
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() triangle_split_dir=%d\n", splitDir );
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() triangle_idx0=%d\n", candIdx0 );
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() triangle_idx1=%d\n", candIdx1 );
      candIdx1 -= candIdx1 < candIdx0 ? 0 : 1;
      auto encodeOneIdx = [this](uint8_t mrgIdx, int numCandminus1)
      {
        if(mrgIdx == 0)
        {
          this->m_BinEncoder.encodeBin( 0, Ctx::MergeIdx() );
          return;
        }
        else
        {
          this->m_BinEncoder.encodeBin( 1, Ctx::MergeIdx() );
          for( unsigned idx = 1; idx < numCandminus1; idx++ )
          {
            this->m_BinEncoder.encodeBinEP( mrgIdx == idx ? 0 : 1 );
            if( mrgIdx == idx )
            {
              break;
            }
          }
        }
      };
      m_BinEncoder.encodeBinEP(splitDir);
      encodeOneIdx(candIdx0, TRIANGLE_MAX_NUM_UNI_CANDS - 1);
      encodeOneIdx(candIdx1, TRIANGLE_MAX_NUM_UNI_CANDS - 2);
#else
      if( pu.mergeIdx < 2 )
      {
        m_BinEncoder.encodeBin( 0, Ctx::TriangleIdx() );
        m_BinEncoder.encodeBinEP( pu.mergeIdx );
      }
      else
      {
        m_BinEncoder.encodeBin( 1, Ctx::TriangleIdx() );
        exp_golomb_eqprob( pu.mergeIdx - 2, 2 );
      }

      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() triangle_idx=%d\n", pu.mergeIdx );
#endif
      return;
    }
  int numCandminus1 = int( pu.cs->slice->getMaxNumMergeCand() ) - 1;
  if( numCandminus1 > 0 )
  {
    if( pu.mergeIdx == 0 )
    {
      m_BinEncoder.encodeBin( 0, Ctx::MergeIdx() );
      DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() merge_idx=%d\n", pu.mergeIdx );
      return;
    }
    else
    {
      m_BinEncoder.encodeBin( 1, Ctx::MergeIdx() );
      for( unsigned idx = 1; idx < numCandminus1; idx++ )
      {
          m_BinEncoder.encodeBinEP( pu.mergeIdx == idx ? 0 : 1 );
        if( pu.mergeIdx == idx )
        {
          break;
        }
      }
    }
  }
  DTRACE( g_trace_ctx, D_SYNTAX, "merge_idx() merge_idx=%d\n", pu.mergeIdx );
  }
}
void CABACWriter::mmvd_merge_idx(const PredictionUnit& pu)
{
  int var0, var1, var2;
  int mvpIdx = pu.mmvdMergeIdx;
  var0 = mvpIdx / MMVD_MAX_REFINE_NUM;
  var1 = (mvpIdx - (var0 * MMVD_MAX_REFINE_NUM)) / 4;
  var2 = mvpIdx - (var0 * MMVD_MAX_REFINE_NUM) - var1 * 4;

  int numCandminus1_base = MMVD_BASE_MV_NUM - 1;
  if (numCandminus1_base > 0)
  {
    if (var0 == 0)
    {
      m_BinEncoder.encodeBin(0, Ctx::MmvdMergeIdx());
    }
    else
    {
      m_BinEncoder.encodeBin(1, Ctx::MmvdMergeIdx());
      for (unsigned idx = 1; idx < numCandminus1_base; idx++)
      {
        m_BinEncoder.encodeBinEP(var0 == idx ? 0 : 1);
        if (var0 == idx)
        {
          break;
        }
      }
    }
  }
  DTRACE(g_trace_ctx, D_SYNTAX, "base_mvp_idx() base_mvp_idx=%d\n", var0);

  int numCandminus1_step = MMVD_REFINE_STEP - 1;
  if (numCandminus1_step > 0)
  {
    if (var1 == 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(var1 == idx ? 0 : 1);
        if (var1 == idx)
        {
          break;
        }
      }
    }
  }
  DTRACE(g_trace_ctx, D_SYNTAX, "MmvdStepMvpIdx() MmvdStepMvpIdx=%d\n", var1);

  m_BinEncoder.encodeBinsEP(var2, 2);

  DTRACE(g_trace_ctx, D_SYNTAX, "pos() pos=%d\n", var2);
  DTRACE(g_trace_ctx, D_SYNTAX, "mmvd_merge_idx() mmvd_merge_idx=%d\n", pu.mmvdMergeIdx);
}
void CABACWriter::inter_pred_idc( const PredictionUnit& pu )
{
  if( !pu.cs->slice->isInterB() )
  {
    return;
  }
  if( !(PU::isBipredRestriction(pu)) )
  {
    unsigned ctxId = DeriveCtx::CtxInterDir(pu);
    if( pu.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, pu.interDir, pu.lumaPos().x, pu.lumaPos().y );
      return;
    }
    else
    {
      m_BinEncoder.encodeBin( 0, Ctx::InterDir(ctxId) );
    }
  }
  m_BinEncoder.encodeBin( ( pu.interDir == 2 ), Ctx::InterDir( 4 ) );
  DTRACE( g_trace_ctx, D_SYNTAX, "inter_pred_idc() ctx=4 value=%d pos=(%d,%d)\n", pu.interDir, pu.lumaPos().x, pu.lumaPos().y );
}


void CABACWriter::ref_idx( const PredictionUnit& pu, RefPicList eRefList )
{
#if JVET_M0444_SMVD
  if ( pu.cu->smvdMode )
  {
    CHECK( pu.refIdx[eRefList] != pu.cs->slice->getSymRefIdx( eRefList ), "Invalid reference index!\n" );
    return;
  }
#endif

  int numRef  = pu.cs->slice->getNumRefIdx(eRefList);
  if( numRef <= 1 )
  {
    return;
  }
  int refIdx  = pu.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, pu.lumaPos().x, pu.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, pu.lumaPos().x, pu.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, pu.lumaPos().x, pu.lumaPos().y );
}

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

void CABACWriter::MHIntra_flag(const PredictionUnit& pu)
{
  if (!pu.cs->sps->getSpsNext().getUseMHIntra())
  {
    CHECK(pu.mhIntraFlag == true, "invalid MHIntra SPS");
    return;
  }
  if (pu.cu->skip)
  {
    CHECK(pu.mhIntraFlag == true, "invalid MHIntra and skip");
    return;
  }
  if (pu.mmvdMergeFlag)
  {
    CHECK(pu.mhIntraFlag == true, "invalid MHIntra and mmvd");
    return;
  }
  if (pu.cu->affine)
  {
    CHECK(pu.mhIntraFlag == true, "invalid MHIntra and affine");
    return;
  }
  if (pu.cu->lwidth() * pu.cu->lheight() < 64 || pu.cu->lwidth() >= MAX_CU_SIZE || pu.cu->lheight() >= MAX_CU_SIZE)
  {
    CHECK(pu.mhIntraFlag == true, "invalid MHIntra and blk");
    return;
  }
  m_BinEncoder.encodeBin(pu.mhIntraFlag, Ctx::MHIntraFlag());
  DTRACE(g_trace_ctx, D_SYNTAX, "MHIntra_flag() MHIntra=%d pos=(%d,%d) size=%dx%d\n", pu.mhIntraFlag ? 1 : 0, pu.lumaPos().x, pu.lumaPos().y, pu.lumaSize().width, pu.lumaSize().height);
}

void CABACWriter::MHIntra_luma_pred_modes(const CodingUnit& cu)
{
  if (!cu.Y().valid())
  {
    return;
  }

  const int numMPMs = 3;
  int      numBlocks = CU::getNumPUs(cu);
  unsigned mpm_idxs[4];
  unsigned pred_modes[4];

  const PredictionUnit* pu = cu.firstPU;

  unsigned mpm_pred[numMPMs];
  for (int k = 0; k < numBlocks; k++)
  {
    unsigned&  mpm_idx = mpm_idxs[k];
    unsigned&  pred_mode = pred_modes[k];

    PU::getMHIntraMPMs(*pu, mpm_pred);

    pred_mode = pu->intraDir[0];

    mpm_idx = numMPMs;

    for (int idx = 0; idx < numMPMs; idx++)
    {
      if (pred_mode == mpm_pred[idx])
      {
        mpm_idx = idx;
        break;
      }
    }
    if (PU::getNarrowShape(pu->lwidth(), pu->lheight()) == 0)
    {
      m_BinEncoder.encodeBin(mpm_idx < numMPMs, Ctx::MHIntraPredMode());
    }
    pu = pu->next;
  }

  pu = cu.firstPU;

  // mpm_idx / rem_intra_luma_pred_mode
  for (int k = 0; k < numBlocks; k++)
  {
    const unsigned& mpm_idx = mpm_idxs[k];
    if (mpm_idx < numMPMs)
    {
      m_BinEncoder.encodeBinEP(mpm_idx > 0);
      if (mpm_idx)
      {
        m_BinEncoder.encodeBinEP(mpm_idx > 1);
      }
    }
    DTRACE(g_trace_ctx, D_SYNTAX, "intra_luma_pred_modes() idx=%d pos=(%d,%d) mode=%d\n", k, pu->lumaPos().x, pu->lumaPos().y, pu->intraDir[0]);
    pu = pu->next;
  }
}

void CABACWriter::triangle_mode( const CodingUnit& cu )
{
  if( !cu.cs->slice->getSPS()->getSpsNext().getUseTriangle() || !cu.cs->slice->isInterB() || cu.lwidth() * cu.lheight() < TRIANGLE_MIN_SIZE || cu.affine )
  {
    return;
  }

#if JVET_M0118_M0185_TRIANGLE_FLAG_FIX
  if ( cu.firstPU->mmvdMergeFlag || cu.mmvdSkip )
  {
    return;
  }

  if ( cu.firstPU->mhIntraFlag )
  {
    return;
  }
#endif

  unsigned flag_idx     = DeriveCtx::CtxTriangleFlag( cu );

  m_BinEncoder.encodeBin( cu.triangle, Ctx::TriangleFlag(flag_idx) );

  DTRACE( g_trace_ctx, D_SYNTAX, "triangle_mode() triangle_mode=%d pos=(%d,%d) size: %dx%d\n", cu.triangle, cu.Y().x, cu.Y().y, cu.lumaSize().width, cu.lumaSize().height );
}

//================================================================================
//  clause 7.3.8.7
//--------------------------------------------------------------------------------
//    void  pcm_samples( tu )
//================================================================================

void CABACWriter::pcm_samples( const TransformUnit& tu )
{
  CHECK( !tu.cu->ipcm, "pcm mode expected" );

  const SPS&        sps       = *tu.cu->cs->sps;

  const CodingStructure *cs = tu.cs;
  const ChannelType chType = tu.chType;

  ComponentID compStr = (CS::isDualITree(*cs) && !isLuma(chType)) ? COMPONENT_Cb: COMPONENT_Y;
  ComponentID compEnd = (CS::isDualITree(*cs) && isLuma(chType)) ? COMPONENT_Y : COMPONENT_Cr;
  for( ComponentID compID = compStr; compID <= compEnd; compID = ComponentID(compID+1) )
  {
    const CPelBuf   samples     = tu.getPcmbuf( compID );
    const unsigned  sampleBits  = sps.getPCMBitDepth( toChannelType(compID) );
    for( unsigned y = 0; y < samples.height; y++ )
    {
      for( unsigned x = 0; x < samples.width; x++ )
      {
        m_BinEncoder.encodeBinsPCM( samples.at(x, y), sampleBits );
      }
    }
  }
  m_BinEncoder.restart();
}



//================================================================================
//  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, ChromaCbfs& chromaCbfs )
{
  const UnitArea&       area          = partitioner.currArea();
  const TransformUnit&  tu            = *cs.getTU( area.blocks[partitioner.chType].pos(), partitioner.chType );
  const CodingUnit&     cu            = *tu.cu;
  const unsigned        trDepth       = partitioner.currTrDepth;
  const bool            split         = ( tu.depth > trDepth );

  // split_transform_flag
  if( partitioner.canSplit( TU_MAX_TR_SPLIT, cs ) )
  {
    CHECK( !split, "transform split implied" );
  }
  else
  CHECK( split, "transform split not allowed with QTBT" );

  // cbf_cb & cbf_cr
  if( area.chromaFormat != CHROMA_400 && area.blocks[COMPONENT_Cb].valid() && ( !CS::isDualITree( cs ) || partitioner.chType == CHANNEL_TYPE_CHROMA ) )
  {
    {
      if( trDepth == 0 || chromaCbfs.Cb )
      {
        chromaCbfs.Cb = TU::getCbfAtDepth( tu, COMPONENT_Cb, trDepth );
        cbf_comp( cs, chromaCbfs.Cb, area.blocks[COMPONENT_Cb], trDepth );
      }
      else
      {
        CHECK( TU::getCbfAtDepth( tu, COMPONENT_Cb, trDepth ) != chromaCbfs.Cb, "incorrect Cb cbf" );
      }

      if( trDepth == 0 || chromaCbfs.Cr )
      {
        chromaCbfs.Cr = TU::getCbfAtDepth( tu, COMPONENT_Cr,   trDepth );
        cbf_comp( cs, chromaCbfs.Cr, area.blocks[COMPONENT_Cr], trDepth, chromaCbfs.Cb );
      }
      else
      {
        CHECK( TU::getCbfAtDepth( tu, COMPONENT_Cr, trDepth ) != chromaCbfs.Cr, "incorrect Cr cbf" );
      }
    }
  }
  else if( CS::isDualITree( cs ) )
  {
    chromaCbfs = ChromaCbfs( false );
  }

  if( split )
  {
    if( area.chromaFormat != CHROMA_400 )
    {
      chromaCbfs.Cb        = TU::getCbfAtDepth( tu, COMPONENT_Cb,  trDepth );
      chromaCbfs.Cr        = TU::getCbfAtDepth( tu, COMPONENT_Cr,  trDepth );
    }
#if !JVET_M0464_UNI_MTS
    if( trDepth == 0 ) emt_cu_flag( cu );
#endif

    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
      THROW( "Implicit TU split not available" );

    do
    {
      ChromaCbfs subChromaCbfs = chromaCbfs;
      transform_tree( cs, partitioner, cuCtx, subChromaCbfs );
    } while( partitioner.nextPart( cs ) );

    partitioner.exitCurrSplit();
  }
  else
  {
    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 );

    if( !isChroma( partitioner.chType ) )
    {
      if( !CU::isIntra( cu ) && trDepth == 0 && !chromaCbfs.sigChroma( area.chromaFormat ) )
      {
        CHECK( !TU::getCbfAtDepth( tu, COMPONENT_Y, trDepth ), "Luma cbf must be true for inter units with no chroma coeffs" );
      }
      else
      {
        cbf_comp( cs, TU::getCbfAtDepth( tu, COMPONENT_Y, trDepth ), tu.Y(), trDepth );
      }
    }

#if !JVET_M0464_UNI_MTS
    if( trDepth == 0 && TU::getCbfAtDepth( tu, COMPONENT_Y, 0 ) ) emt_cu_flag( cu );
#endif

    transform_unit( tu, cuCtx, chromaCbfs );
  }
}

void CABACWriter::cbf_comp( const CodingStructure& cs, bool cbf, const CompArea& area, unsigned depth, const bool prevCbCbf )
{
  const unsigned  ctxId   = DeriveCtx::CtxQtCbf( area.compID, depth, prevCbCbf );
  const CtxSet&   ctxSet  = Ctx::QtCbf[ 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