HM学习——xCompressCU函数

xCompressCU

Xcompresscu 主要完成块划分（包括CU,PU,TU划分），pu预测模式选择，期间继续调用函数完成帧间预测帧内预测，PCM模式测试。包括1.帧间预测xCheckRDCostInter、xCheckRDCostMerge2Nx2N2.帧内预测xCheckRDCostIntra3.PCM模式xCheckIntraPCM

整个xcompressCU之中完成了一个LCU所有可能的CU划分模式，以及pu(或tu)所有的模式。并且进行了其中PU的帧间帧内PCM的所有预测模式，搜有以上提到的这些过程都通过率失真优化技术，选择出最优的划分模式以及选择模式.下图是整个函数的流程图。

代码如下：

#if AMP_ENC_SPEEDUP
Void TEncCu::xCompressCU( TComDataCU*& rpcBestCU, TComDataCU*& rpcTempCU, const UInt uiDepth DEBUG_STRING_FN_DECLARE(sDebug_), PartSize eParentPartSize )
#else
Void TEncCu::xCompressCU( TComDataCU*& rpcBestCU, TComDataCU*& rpcTempCU, const UInt uiDepth )
#endif
{
   
  TComPic* pcPic = rpcBestCU->getPic();
  DEBUG_STRING_NEW(sDebug)
  const TComPPS &pps=*(rpcTempCU->getSlice()->getPPS());
  const TComSPS &sps=*(rpcTempCU->getSlice()->getSPS());
  
  // These are only used if getFastDeltaQp() is true
  const UInt fastDeltaQPCuMaxSize    = Clip3(sps.getMaxCUHeight()>>sps.getLog2DiffMaxMinCodingBlockSize(), sps.getMaxCUHeight(), 32u);

  // get Original YUV data from picture
  m_ppcOrigYuv[uiDepth]->copyFromPicYuv( pcPic->getPicYuvOrg(), rpcBestCU->getCtuRsAddr(), rpcBestCU->getZorderIdxInCtu() );

  // variable for Cbf fast mode PU decision
  Bool    doNotBlockPu = true;
  Bool    earlyDetectionSkipMode = false;

  const UInt uiLPelX   = rpcBestCU->getCUPelX();
  const UInt uiRPelX   = uiLPelX + rpcBestCU->getWidth(0)  - 1;
  const UInt uiTPelY   = rpcBestCU->getCUPelY();
  const UInt uiBPelY   = uiTPelY + rpcBestCU->getHeight(0) - 1;
  const UInt uiWidth   = rpcBestCU->getWidth(0);

  Int iBaseQP = xComputeQP( rpcBestCU, uiDepth );
  Int iMinQP;
  Int iMaxQP;
  Bool isAddLowestQP = false;

  const UInt numberValidComponents = rpcBestCU->getPic()->getNumberValidComponents();

  if( uiDepth <= pps.getMaxCuDQPDepth() )
  {
   
    Int idQP = m_pcEncCfg->getMaxDeltaQP();
    iMinQP = Clip3( -sps.getQpBDOffset(CHANNEL_TYPE_LUMA), MAX_QP, iBaseQP-idQP );
    iMaxQP = Clip3( -sps.getQpBDOffset(CHANNEL_TYPE_LUMA), MAX_QP, iBaseQP+idQP );
  }
  else
  {
   
    iMinQP = rpcTempCU->getQP(0);
    iMaxQP = rpcTempCU->getQP(0);
  }

  if ( m_pcEncCfg->getLumaLevelToDeltaQPMapping().isEnabled() )
  {
   
    if ( uiDepth <= pps.getMaxCuDQPDepth() )
    {
   
      // keep using the same m_QP_LUMA_OFFSET in the same CTU
      m_lumaQPOffset = calculateLumaDQP(rpcTempCU, 0, m_ppcOrigYuv[uiDepth]);
    }
    iMinQP = Clip3(-sps.getQpBDOffset(CHANNEL_TYPE_LUMA), MAX_QP, iBaseQP - m_lumaQPOffset);
    iMaxQP = iMinQP; // force encode choose the modified QO
  }

  if ( m_pcEncCfg->getUseRateCtrl() )
  {
   
    iMinQP = m_pcRateCtrl->getRCQP();
    iMaxQP = m_pcRateCtrl->getRCQP();
  }

  // transquant-bypass (TQB) processing loop variable initialisation ---

  const Int lowestQP = iMinQP; // For TQB, use this QP which is the lowest non TQB QP tested (rather than QP'=0) - that way delta QPs are smaller, and TQB can be tested at all CU levels.

  if ( (pps.getTransquantBypassEnabledFlag()) )
  {
   
    isAddLowestQP = true; // mark that the first iteration is to cost TQB mode.
    iMinQP = iMinQP - 1;  // increase loop variable range by 1, to allow testing of TQB mode along with other QPs
    if ( m_pcEncCfg->getCUTransquantBypassFlagForceValue() )
    {
   
      iMaxQP = iMinQP;
    }
  }

  TComSlice * pcSlice = rpcTempCU->getPic()->getSlice(rpcTempCU->getPic()->getCurrSliceIdx());

  const Bool bBoundary = !( uiRPelX < sps.getPicWidthInLumaSamples() && uiBPelY < sps.getPicHeightInLumaSamples() );

  if ( !bBoundary )
  {
   
    for (Int iQP=iMinQP; iQP<=iMaxQP; iQP++)
    {
   
      const Bool bIsLosslessMode = isAddLowestQP && (iQP == iMinQP);

      if (bIsLosslessMode)
      {
   
        iQP = lowestQP;
      }
      if ( m_pcEncCfg->getLumaLevelToDeltaQPMapping().isEnabled() && uiDepth <= pps.getMaxCuDQPDepth() )
      {
   
        getSliceEncoder()->updateLambda(pcSlice, iQP);
      }

      m_cuChromaQpOffsetIdxPlus1 = 0;
      if (pcSlice->getUseChromaQpAdj())
      {
   
        /* Pre-estimation of chroma QP based on input block activity may be performed
         * here, using for example m_ppcOrigYuv[uiDepth] */
        /* To exercise the current code, the index used for adjustment is based on
         * block position
         */
        Int lgMinCuSize = sps.getLog2MinCodingBlockSize() +
                          std::max<Int>(0, sps.getLog2DiffMaxMinCodingBlockSize()-Int(pps.getPpsRangeExtension().getDiffCuChromaQpOffsetDepth()));
        m_cuChromaQpOffsetIdxPlus1 = ((uiLPelX >> lgMinCuSize) + (uiTPelY >> lgMinCuSize)) % (pps.getPpsRangeExtension().getChromaQpOffsetListLen() + 1);
      }

      rpcTempCU->initEstData( uiDepth, iQP, bIsLosslessMode );

      // do inter modes, SKIP and 2Nx2N
	
      if( rpcBestCU->getSlice()->getSliceType() != I_SLICE )
      {
   
        // 2Nx2N
        if(m_pcEncCfg->getUseEarlySkipDetection())
        {
   
          xCheckRDCostInter( rpcBestCU, rpcTempCU, SIZE_2Nx2N DEBUG_STRING_PASS_INTO(sDebug) );
          rpcTempCU->initEstData( uiDepth, iQP, bIsLosslessMode );//by Competition for inter_2Nx2N
        }
        // SKIP
        xCheckRDCostMerge2Nx2N( rpcBestCU, rpcTempCU DEBUG_STRING_PASS_INTO(sDebug), &earlyDetectionSkipMode );//by Merge for inter_2Nx2N
        rpcTempCU->in