-Merge模式
Merge模式定义
Merge模式为当前PU建立一个MV的候选列表（包含5个候选MV及其对应的参考图像）。计算这五个候选MV的率失真代价（RDcost），选取最优的MV。（其中空域最多4个）
Merge模式候选列表的建立
空域列表
列表按照A1→B1→B0→A0（B2是替补）
若PU不是正方形，则需要注意其他的位置，则A1不存在，因为PU1与PU2MV不能一样（否则就直接是2N*2N模式）
时域列表
临近已编码图像中对应位置PU。此时不能直接选择候选块的信息，需要根据与参考图像的位置关系做相应的比例伸缩调整。
下面是merge模式的代码。
Void TComDataCU::getInterMergeCandidates( UInt uiAbsPartIdx, UInt uiPUIdx, TComMvField* pcMvFieldNeighbours, UChar* puhInterDirNeighbours, Int& numValidMergeCand, Int mrgCandIdx ) const
{
UInt uiAbsPartAddr = m_absZIdxInCtu + uiAbsPartIdx;
// 候选MV对应的标记
Bool abCandIsInter[ MRG_MAX_NUM_CANDS ];
// 先清空列表
for( UInt ui = 0; ui < getSlice()->getMaxNumMergeCand(); ++ui )
{
abCandIsInter[ui] = false;
pcMvFieldNeighbours[ ( ui << 1 ) ].setRefIdx(NOT_VALID);
pcMvFieldNeighbours[ ( ui << 1 ) + 1 ].setRefIdx(NOT_VALID);
}
// 获取有效的候选数量
numValidMergeCand = getSlice()->getMaxNumMergeCand();
// compute the location of the current PU 计算当前PU的位置
Int xP, yP, nPSW, nPSH; //xp，yp表示location of the upper-left corner pixel of the current PU
this->getPartPosition(uiPUIdx, xP, yP, nPSW, nPSH);// nPSW,nPSH 当前PU的大小
Int iCount = 0; // 候选模式的数量
UInt uiPartIdxLT, uiPartIdxRT, uiPartIdxLB;
PartSize cCurPS = getPartitionSize( uiAbsPartIdx );
// 转换成索引
deriveLeftRightTopIdxGeneral( uiAbsPartIdx, uiPUIdx, uiPartIdxLT, uiPartIdxRT );
deriveLeftBottomIdxGeneral( uiAbsPartIdx, uiPUIdx, uiPartIdxLB );
// 开始进行空域MV预测，处理的顺序是 左边——>上边——>右上角——>左下角——>左上角
//left 左侧
UInt uiLeftPartIdx = 0;
const TComDataCU *pcCULeft = getPULeft( uiLeftPartIdx, uiPartIdxLB );
Bool isAvailableA1 = pcCULeft &&
pcCULeft->isDiffMER(xP -1, yP+nPSH-1, xP, yP) &&
!( uiPUIdx == 1 && (cCurPS == SIZE_Nx2N || cCurPS == SIZE_nLx2N || cCurPS == SIZE_nRx2N) ) &&
pcCULeft->isInter( uiLeftPartIdx ) ;
if ( isAvailableA1 )
{
abCandIsInter[iCount] = true;
// get Inter Dir
puhInterDirNeighbours[iCount] = pcCULeft->getInterDir( uiLeftPartIdx );
// get Mv from Left
TComDataCU::getMvField( pcCULeft, uiLeftPartIdx, REF_PIC_LIST_0, pcMvFieldNeighbours[iCount<<1] );
if ( getSlice()->isInterB() )
{
TComDataCU::getMvField( pcCULeft, uiLeftPartIdx, REF_PIC_LIST_1, pcMvFieldNeighbours[(iCount<<1)+1] );
}
if ( mrgCandIdx == iCount )
{
return;
}
iCount ++;
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
// above 上方
UInt uiAbovePartIdx = 0;
const TComDataCU *pcCUAbove = getPUAbove( uiAbovePartIdx, uiPartIdxRT );
Bool isAvailableB1 = pcCUAbove &&
pcCUAbove->isDiffMER(xP+nPSW-1, yP-1, xP, yP) &&
!( uiPUIdx == 1 && (cCurPS == SIZE_2NxN || cCurPS == SIZE_2NxnU || cCurPS == SIZE_2NxnD) ) &&
pcCUAbove->isInter( uiAbovePartIdx );
if ( isAvailableB1 && (!isAvailableA1 || !pcCULeft->hasEqualMotion( uiLeftPartIdx, pcCUAbove, uiAbovePartIdx ) ) )
{
abCandIsInter[iCount] = true;
// get Inter Dir
puhInterDirNeighbours[iCount] = pcCUAbove->getInterDir( uiAbovePartIdx );
// get Mv from Left
TComDataCU::getMvField( pcCUAbove, uiAbovePartIdx, REF_PIC_LIST_0, pcMvFieldNeighbours[iCount<<1] );
if ( getSlice()->isInterB() )
{
TComDataCU::getMvField( pcCUAbove, uiAbovePartIdx, REF_PIC_LIST_1, pcMvFieldNeighbours[(iCount<<1)+1] );
}
if ( mrgCandIdx == iCount )
{
return;
}
iCount ++;
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
// above right 右上
UInt uiAboveRightPartIdx = 0;
const TComDataCU *pcCUAboveRight = getPUAboveRight( uiAboveRightPartIdx, uiPartIdxRT );
Bool isAvailableB0 = pcCUAboveRight &&
pcCUAboveRight->isDiffMER(xP+nPSW, yP-1, xP, yP) &&
pcCUAboveRight->isInter( uiAboveRightPartIdx );
if ( isAvailableB0 && ( !isAvailableB1 || !pcCUAbove->hasEqualMotion( uiAbovePartIdx, pcCUAboveRight, uiAboveRightPartIdx ) ) )
{
abCandIsInter[iCount] = true;
// get Inter Dir
puhInterDirNeighbours[iCount] = pcCUAboveRight->getInterDir( uiAboveRightPartIdx );
// get Mv from Left
TComDataCU::getMvField( pcCUAboveRight, uiAboveRightPartIdx, REF_PIC_LIST_0, pcMvFieldNeighbours[iCount<<1] );
if ( getSlice()->isInterB() )
{
TComDataCU::getMvField( pcCUAboveRight, uiAboveRightPartIdx, REF_PIC_LIST_1, pcMvFieldNeighbours[(iCount<<1)+1] );
}
if ( mrgCandIdx == iCount )
{
return;
}
iCount ++;
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
//left bottom 左下
UInt uiLeftBottomPartIdx = 0;
const TComDataCU *pcCULeftBottom = this->getPUBelowLeft( uiLeftBottomPartIdx, uiPartIdxLB );
Bool isAvailableA0 = pcCULeftBottom &&
pcCULeftBottom->isDiffMER(xP-1, yP+nPSH, xP, yP) &&
pcCULeftBottom->isInter( uiLeftBottomPartIdx ) ;
if ( isAvailableA0 && ( !isAvailableA1 || !pcCULeft->hasEqualMotion( uiLeftPartIdx, pcCULeftBottom, uiLeftBottomPartIdx ) ) )
{
abCandIsInter[iCount] = true;
// get Inter Dir
puhInterDirNeighbours[iCount] = pcCULeftBottom->getInterDir( uiLeftBottomPartIdx );
// get Mv from Left
TComDataCU::getMvField( pcCULeftBottom, uiLeftBottomPartIdx, REF_PIC_LIST_0, pcMvFieldNeighbours[iCount<<1] );
if ( getSlice()->isInterB() )
{
TComDataCU::getMvField( pcCULeftBottom, uiLeftBottomPartIdx, REF_PIC_LIST_1, pcMvFieldNeighbours[(iCount<<1)+1] );
}
if ( mrgCandIdx == iCount )
{
return;
}
iCount ++;
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
// above left 左上
if( iCount < 4 )
{
UInt uiAboveLeftPartIdx = 0;
const TComDataCU *pcCUAboveLeft = getPUAboveLeft( uiAboveLeftPartIdx, uiAbsPartAddr );
Bool isAvailableB2 = pcCUAboveLeft &&
pcCUAboveLeft->isDiffMER(xP-1, yP-1, xP, yP) &&
pcCUAboveLeft->isInter( uiAboveLeftPartIdx );
if ( isAvailableB2 && ( !isAvailableA1 || !pcCULeft->hasEqualMotion( uiLeftPartIdx, pcCUAboveLeft, uiAboveLeftPartIdx ) )
&& ( !isAvailableB1 || !pcCUAbove->hasEqualMotion( uiAbovePartIdx, pcCUAboveLeft, uiAboveLeftPartIdx ) ) )
{
abCandIsInter[iCount] = true;
// get Inter Dir
puhInterDirNeighbours[iCount] = pcCUAboveLeft->getInterDir( uiAboveLeftPartIdx );
// get Mv from Left
TComDataCU::getMvField( pcCUAboveLeft, uiAboveLeftPartIdx, REF_PIC_LIST_0, pcMvFieldNeighbours[iCount<<1] );
if ( getSlice()->isInterB() )
{
TComDataCU::getMvField( pcCUAboveLeft, uiAboveLeftPartIdx, REF_PIC_LIST_1, pcMvFieldNeighbours[(iCount<<1)+1] );
}
if ( mrgCandIdx == iCount )
{
return;
}
iCount ++;
}
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
// 如果使用了TMVP（就是时域的MVP（MVP是MV预测）），上面的都是空域MV预测
if ( getSlice()->getEnableTMVPFlag() )
{
//>> MTK colocated-RightBottom
UInt uiPartIdxRB;
deriveRightBottomIdx( uiPUIdx, uiPartIdxRB );
UInt uiAbsPartIdxTmp = g_auiZscanToRaster[uiPartIdxRB];
const UInt numPartInCtuWidth = m_pcPic->getNumPartInCtuWidth();
const UInt numPartInCtuHeight = m_pcPic->getNumPartInCtuHeight();
TComMv cColMv;
Int iRefIdx;
Int ctuRsAddr = -1;
if ( ( ( m_pcPic->getCtu(m_ctuRsAddr)->getCUPelX() + g_auiRasterToPelX[uiAbsPartIdxTmp] + m_pcPic->getMinCUWidth () ) < m_pcSlice->getSPS()->getPicWidthInLumaSamples () ) // image boundary check
&& ( ( m_pcPic->getCtu(m_ctuRsAddr)->getCUPelY() + g_auiRasterToPelY[uiAbsPartIdxTmp] + m_pcPic->getMinCUHeight() ) < m_pcSlice->getSPS()->getPicHeightInLumaSamples() ) )
{
if ( ( uiAbsPartIdxTmp % numPartInCtuWidth < numPartInCtuWidth - 1 ) && // is not at the last column of CTU
( uiAbsPartIdxTmp / numPartInCtuWidth < numPartInCtuHeight - 1 ) ) // is not at the last row of CTU
{
uiAbsPartAddr = g_auiRasterToZscan[ uiAbsPartIdxTmp + numPartInCtuWidth + 1 ];
ctuRsAddr = getCtuRsAddr();
}
else if ( uiAbsPartIdxTmp % numPartInCtuWidth < numPartInCtuWidth - 1 ) // is not at the last column of CTU But is last row of CTU
{
uiAbsPartAddr = g_auiRasterToZscan[ (uiAbsPartIdxTmp + numPartInCtuWidth + 1) % m_pcPic->getNumPartitionsInCtu() ];
}
else if ( uiAbsPartIdxTmp / numPartInCtuWidth < numPartInCtuHeight - 1 ) // is not at the last row of CTU But is last column of CTU
{
uiAbsPartAddr = g_auiRasterToZscan[ uiAbsPartIdxTmp + 1 ];
ctuRsAddr = getCtuRsAddr() + 1;
}
else //is the right bottom corner of CTU
{
uiAbsPartAddr = 0;
}
}
iRefIdx = 0;
Bool bExistMV = false;
UInt uiPartIdxCenter;
Int dir = 0;
UInt uiArrayAddr = iCount;
xDeriveCenterIdx( uiPUIdx, uiPartIdxCenter );
// 从参考列表中找到预测的MV（xGetColMVP是个比较重要的函数，它的作用是从参考帧中找打MVP）
bExistMV = ctuRsAddr >= 0 && xGetColMVP( REF_PIC_LIST_0, ctuRsAddr, uiAbsPartAddr, cColMv, iRefIdx );
if( bExistMV == false )
{
bExistMV = xGetColMVP( REF_PIC_LIST_0, getCtuRsAddr(), uiPartIdxCenter, cColMv, iRefIdx );
}
if( bExistMV )
{
dir |= 1;
pcMvFieldNeighbours[ 2 * uiArrayAddr ].setMvField( cColMv, iRefIdx );
}
// 如果是B帧，那么还需要在list中查找
if ( getSlice()->isInterB() )
{
bExistMV = ctuRsAddr >= 0 && xGetColMVP( REF_PIC_LIST_1, ctuRsAddr, uiAbsPartAddr, cColMv, iRefIdx);
if( bExistMV == false )
{
bExistMV = xGetColMVP( REF_PIC_LIST_1, getCtuRsAddr(), uiPartIdxCenter, cColMv, iRefIdx );
}
if( bExistMV )
{
dir |= 2;
pcMvFieldNeighbours[ 2 * uiArrayAddr + 1 ].setMvField( cColMv, iRefIdx );
}
}
if (dir != 0)
{
puhInterDirNeighbours[uiArrayAddr] = dir;
abCandIsInter[uiArrayAddr] = true;
if ( mrgCandIdx == iCount )
{
return;
}
iCount++;
}
}
// early termination
if (iCount == getSlice()->getMaxNumMergeCand())
{
return;
}
UInt uiArrayAddr = iCount;
UInt uiCutoff = uiArrayAddr;
// 如果是B帧
if ( getSlice()->isInterB() )
{
static const UInt NUM_PRIORITY_LIST=12;
static const UInt uiPriorityList0[NUM_PRIORITY_LIST] = {0 , 1, 0, 2, 1, 2, 0, 3, 1, 3, 2, 3};
static const UInt uiPriorityList1[NUM_PRIORITY_LIST] = {1 , 0, 2, 0, 2, 1, 3, 0, 3, 1, 3, 2};
for (Int idx=0; idxgetMaxNumMergeCand(); idx++)
{
assert(idxgetRefPOC( REF_PIC_LIST_0, pcMvFieldNeighbours[(uiArrayAddr<<1)].getRefIdx() );
Int iRefPOCL1 = m_pcSlice->getRefPOC( REF_PIC_LIST_1, pcMvFieldNeighbours[(uiArrayAddr<<1)+1].getRefIdx() );
if (iRefPOCL0 == iRefPOCL1 && pcMvFieldNeighbours[(uiArrayAddr<<1)].getMv() == pcMvFieldNeighbours[(uiArrayAddr<<1)+1].getMv())
{
abCandIsInter[uiArrayAddr] = false;
}
else
{
uiArrayAddr++;
}
}
}
}
// early termination
if (uiArrayAddr == getSlice()->getMaxNumMergeCand())
{
return;
}
Int iNumRefIdx = (getSlice()->isInterB()) ? min(m_pcSlice->getNumRefIdx(REF_PIC_LIST_0), m_pcSlice->getNumRefIdx(REF_PIC_LIST_1)) : m_pcSlice->getNumRefIdx(REF_PIC_LIST_0);
Int r = 0;
Int refcnt = 0;
// 如果有必要，那么填充0向量
while (uiArrayAddr < getSlice()->getMaxNumMergeCand())
{
abCandIsInter[uiArrayAddr] = true;
puhInterDirNeighbours[uiArrayAddr] = 1;
pcMvFieldNeighbours[uiArrayAddr << 1].setMvField( TComMv(0, 0), r);
if ( getSlice()->isInterB() )
{
puhInterDirNeighbours[uiArrayAddr] = 3;
pcMvFieldNeighbours[(uiArrayAddr << 1) + 1].setMvField(TComMv(0, 0), r);
}
uiArrayAddr++;
if ( refcnt == iNumRefIdx - 1 )
{
r = 0;
}
else
{
++r;
++refcnt;
}
}
numValidMergeCand = uiArrayAddr;
}
/** Check whether the current PU and a spatial neighboring PU are in a same ME region.
* \param xN, yN location of the upper-left corner pixel of a neighboring PU
* \param xP, yP location of the upper-left corner pixel of the current PU
*/
Bool TComDataCU::isDiffMER(Int xN, Int yN, Int xP, Int yP) const
{
UInt plevel = this->getSlice()->getPPS()->getLog2ParallelMergeLevelMinus2() + 2;
if ((xN>>plevel)!= (xP>>plevel))
{
return true;
}
if ((yN>>plevel)!= (yP>>plevel))
{
return true;
}
return false;
}