HEVC代码追踪（十一。四）:运动估计/补偿之xPatternSearch和xPatternSearchFast

Void TEncSearch::xPatternSearch( TComPattern* pcPatternKey, Pel* piRefY, Int iRefStride, TComMv* pcMvSrchRngLT, TComMv* pcMvSrchRngRB, TComMv& rcMv, UInt& ruiSAD )
{
  Int   iSrchRngHorLeft   = pcMvSrchRngLT->getHor();
  Int   iSrchRngHorRight  = pcMvSrchRngRB->getHor();
  Int   iSrchRngVerTop    = pcMvSrchRngLT->getVer();
  Int   iSrchRngVerBottom = pcMvSrchRngRB->getVer();
  
  UInt  uiSad;
  UInt  uiSadBest         = MAX_UINT;
  Int   iBestX = 0;
  Int   iBestY = 0;
  
  Pel*  piRefSrch;
  
  //-- jclee for using the SAD function pointer
  m_pcRdCost->setDistParam( pcPatternKey, piRefY, iRefStride,  m_cDistParam );
  
  // fast encoder decision: use subsampled SAD for integer ME
  if ( m_pcEncCfg->getUseFastEnc() )
  {
    if ( m_cDistParam.iRows > 8 )
    {
      m_cDistParam.iSubShift = 1;
    }
  }
  
  piRefY += (iSrchRngVerTop * iRefStride);
  for ( Int y = iSrchRngVerTop; y <= iSrchRngVerBottom; y++ )
  {
    for ( Int x = iSrchRngHorLeft; x <= iSrchRngHorRight; x++ )
    {
      //  find min. distortion position
      piRefSrch = piRefY + x;
      m_cDistParam.pCur = piRefSrch;

      setDistParamComp(0);

      m_cDistParam.bitDepth = g_bitDepthY;
      uiSad = m_cDistParam.DistFunc( &m_cDistParam );
      
      // motion cost
      uiSad += m_pcRdCost->getCost( x, y );
      
      if ( uiSad < uiSadBest )
      {
        uiSadBest = uiSad;
        iBestX    = x;
        iBestY    = y;
      }
    }
    piRefY += iRefStride;
  }
  
  rcMv.set( iBestX, iBestY );
  
  ruiSAD = uiSadBest - m_pcRdCost->getCost( iBestX, iBestY );
  return;
}

//先考虑整像素搜索的情况，进入到xPatternSearchFast中去
//先是获得预测的运动矢量，接着调用xTZSearch进行搜索，xTZSearch这个函数相对比较长，里面调用了很多子函数
Void TEncSearch::xPatternSearchFast( TComDataCU* pcCU, TComPattern* pcPatternKey, Pel* piRefY, Int iRefStride, TComMv* pcMvSrchRngLT, TComMv* pcMvSrchRngRB, TComMv& rcMv, UInt& ruiSAD )
{//!< 获取相邻PU: A, B, C的运动矢量，作为预测运动矢量
  pcCU->getMvPredLeft       ( m_acMvPredictors[0] );
  pcCU->getMvPredAbove      ( m_acMvPredictors[1] );
  pcCU->getMvPredAboveRight ( m_acMvPredictors[2] );
  
  switch ( m_iFastSearch )
  {
    case 1:
      xTZSearch( pcCU, pcPatternKey, piRefY, iRefStride, pcMvSrchRngLT, pcMvSrchRngRB, rcMv, ruiSAD );
      break;
      
    default:
      break;
  }
}