Fix: avoid redundant coding of RPL in both SPS and SH in multilayer

avoid redundant coding of RPL in both SPS and SH in multilayer New parameter "RPLofDepLayerInSH" specify if coding in SPS or SH (default SH)

Currently, RPL are initialized in the SPS from the config file. then in multilayer, for dependent layer, the list is updated with available pictures and inter-layer references and coded in the slice header. Then, when the SPS is coded, RPL still exist with unused values. This solution selects where to code the RPL with an encoder parameter. If it is in SH, the RPL are initialized in the encLib rather than in the SPS directly. This will save roughly 2Kb per GOP 32 sps of dependent layer

source/Lib/EncoderLib/EncLib.cpp

@@ -1953,22 +1953,56 @@ void EncLib::xInitAPS(APS &aps)
 
 void EncLib::xInitRPL(SPS &sps)
 {
-  ReferencePictureList*      rpl;
   const bool                 isFieldCoding = sps.getFieldSeqFlag();
 
   int numRPLCandidates = getRPLCandidateSize(0);
   // To allocate one additional memory for RPL of POC1 (first bottom field) which is not specified in cfg file
-  sps.createRPLList0(numRPLCandidates + (isFieldCoding ? 1 : 0));
-  sps.createRPLList1(numRPLCandidates + (isFieldCoding ? 1 : 0));
-  RPLList* rplList = 0;
+  int layerIdx = getVPS() == nullptr ? 0 : getVPS()->getGeneralLayerIdx(m_layerId);
+  RPLList* rplLists[2];
+  bool codeRplInSH = layerIdx > 0 && getRplOfDepLayerInSh() && getNumRefLayers(layerIdx) > 0 && (getAvoidIntraInDepLayer() || getIntraPeriod() > 1) ;
+  setRplOfDepLayerInSh(codeRplInSH);
+  if (codeRplInSH)
+  {
+    sps.createRPLList0(0);
+    sps.createRPLList1(0);
+    getRPLList(0)->destroy();
+    getRPLList(0)->create(numRPLCandidates + (isFieldCoding ? 1 : 0));
+    getRPLList(1)->destroy();
+    getRPLList(1)->create(numRPLCandidates + (isFieldCoding ? 1 : 0));
+    rplLists[0] = getRPLList(0);
+    rplLists[1] = getRPLList(1);
+  }
+  else
+  {
+    getRPLList(0)->create(0);
+    getRPLList(1)->create(0);
+    sps.createRPLList0(numRPLCandidates + (isFieldCoding ? 1 : 0));
+    sps.createRPLList1(numRPLCandidates + (isFieldCoding ? 1 : 0));
+    rplLists[0] = sps.getRPLList(0);
+    rplLists[1] = sps.getRPLList(1);
+  }
+  static_vector<int, MAX_VPS_LAYERS> refLayersIdx;
+  if (layerIdx > 0 && !getRplOfDepLayerInSh())
+  {
+    if (getNumRefLayers(layerIdx) > 0)
+    {
+      for (int refLayerIdx = 0; refLayerIdx < getNumRefLayers(layerIdx); refLayerIdx++)
+      {
+        if (getVPS()->getDirectRefLayerFlag(layerIdx, refLayerIdx))
+        {
+          refLayersIdx.push_back(refLayerIdx);
+        }
+      }
+    }
+  }
 
   for (int i = 0; i < 2; i++)
   {
-    rplList = (i == 0) ? sps.getRPLList0() : sps.getRPLList1();
+    RPLList* rplList = rplLists[i];
     for (int j = 0; j < numRPLCandidates; j++)
     {
       const RPLEntry &ge = getRPLEntry(i, j);
-      rpl = rplList->getReferencePictureList(j);
+      ReferencePictureList* rpl = rplList->getReferencePictureList(j);
       rpl->setNumberOfShorttermPictures(ge.m_numRefPics);
       rpl->setNumberOfLongtermPictures(0);   //Hardcoded as 0 for now. need to update this when implementing LTRP
       rpl->setNumberOfActivePictures(ge.m_numRefPicsActive);
@@ -1977,9 +2011,42 @@ void EncLib::xInitRPL(SPS &sps)
       // inter-layer reference picture is not signaled in SPS RPL, SPS is shared currently
       rpl->setNumberOfInterLayerPictures( 0 );
 
-      for (int k = 0; k < ge.m_numRefPics; k++)
+      if (!getRplOfDepLayerInSh())
       {
-        rpl->setRefPicIdentifier(k, -ge.m_deltaRefPics[k], 0, false, 0);
+        bool isIntraLayerPredAllowed = getVPS() ? ((getVPS()->getIndependentLayerFlag(layerIdx) || (getVPS()->getPredDirection(ge.m_temporalId) != 1)) && (ge.m_POC % m_intraPeriod) != 0) : true;
+        bool isInterLayerPredAllowed = getVPS() ? (!getVPS()->getIndependentLayerFlag(layerIdx) && (getVPS()->getPredDirection(ge.m_temporalId) != 2) && ((ge.m_POC % m_intraPeriod) != 0 || (getAvoidIntraInDepLayer() && layerIdx))) : false;
+
+        int numRefActive = 0;
+        if (isIntraLayerPredAllowed)
+        {
+          for (int k = 0; k < ge.m_numRefPicsActive; k++)
+          {
+            rpl->setRefPicIdentifier(k, -ge.m_deltaRefPics[k], 0, false, 0);
+          }
+          numRefActive = ge.m_numRefPicsActive;
+        }
+        int validNumILRef = 0;
+        if (isInterLayerPredAllowed)
+        {
+          for (int refLayerIdx : refLayersIdx)
+          {
+            rpl->setRefPicIdentifier(numRefActive + validNumILRef, 0, true, true, m_vps->getInterLayerRefIdc(m_layerId, refLayerIdx));
+            validNumILRef++;
+          }
+          rpl->setNumberOfInterLayerPictures(validNumILRef);
+          rpl->setNumberOfActivePictures(numRefActive + validNumILRef);
+        }
+        for (int k = numRefActive; k < ge.m_numRefPics; k++)
+        {
+          rpl->setRefPicIdentifier(k + validNumILRef, -ge.m_deltaRefPics[k], 0, false, 0);
+        }
+      }
+      else
+      {
+        for (int k = 0; k < ge.m_numRefPics; k++)
+        {
+          rpl->setRefPicIdentifier(k, -ge.m_deltaRefPics[k], 0, false, 0);
+        }
       }
     }
   }
@@ -1989,8 +2056,8 @@ void EncLib::xInitRPL(SPS &sps)
     // To set RPL of POC1 (first bottom field) which is not specified in cfg file
     for (int i = 0; i < 2; i++)
     {
-      rplList = (i == 0) ? sps.getRPLList0() : sps.getRPLList1();
-      rpl = rplList->getReferencePictureList(numRPLCandidates);
+      RPLList* rplList = rplLists[i];
+      ReferencePictureList* rpl = rplList->getReferencePictureList(numRPLCandidates);
       rpl->setNumberOfShorttermPictures(1);
       rpl->setNumberOfLongtermPictures(0);
       rpl->setNumberOfActivePictures(1);
@@ -2001,7 +2068,7 @@ void EncLib::xInitRPL(SPS &sps)
   }
 
   bool isRpl1CopiedFromRpl0 = true;
-  for( int i = 0; isRpl1CopiedFromRpl0 && i < numRPLCandidates; i++)
+  for(int i = 0; isRpl1CopiedFromRpl0 && i < sps.getNumRPL0(); i++)
   {
     if( sps.getRPLList0()->getReferencePictureList(i)->getNumRefEntries() == sps.getRPLList1()->getReferencePictureList(i)->getNumRefEntries() )
     {
@@ -2022,15 +2089,14 @@ void EncLib::xInitRPL(SPS &sps)
 
   //Check if all delta POC of STRP in each RPL has the same sign
   //Check RPLL0 first
-  const RPLList* rplList0 = sps.getRPLList0();
-  const RPLList* rplList1 = sps.getRPLList1();
-  uint32_t numberOfRPL = sps.getNumRPL0();
+  const RPLList* rplList0 = rplLists[0];
+  const RPLList* rplList1 = rplLists[1];
 
   bool isAllEntriesinRPLHasSameSignFlag = true;
-  for (uint32_t ii = 0; isAllEntriesinRPLHasSameSignFlag && ii < numberOfRPL; ii++)
+  for (uint32_t ii = 0; isAllEntriesinRPLHasSameSignFlag && ii < rplList0->getNumberOfReferencePictureLists(); ii++)
   {
     bool isFirstEntry = true;
-    bool lastSign;
+    bool lastSign = true;
 
     const ReferencePictureList* rpl = rplList0->getReferencePictureList(ii);
     for (uint32_t jj = 0; isAllEntriesinRPLHasSameSignFlag && jj < rpl->getNumberOfActivePictures(); jj++)
@@ -2054,11 +2120,10 @@ void EncLib::xInitRPL(SPS &sps)
     }
   }
   //Check RPLL1. Skip it if it is already found out that this flag is not true for RPL0 or if RPL1 is the same as RPL0
-  numberOfRPL = sps.getNumRPL1();
-  for (uint32_t ii = 0; isAllEntriesinRPLHasSameSignFlag && !sps.getRPL1CopyFromRPL0Flag() && ii < numberOfRPL; ii++)
+  for (uint32_t ii = 0; isAllEntriesinRPLHasSameSignFlag && !sps.getRPL1CopyFromRPL0Flag() && ii < rplList1->getNumberOfReferencePictureLists(); ii++)
   {
     bool isFirstEntry = true;
-    bool lastSign;
+    bool lastSign = true;
 
     const ReferencePictureList* rpl = rplList1->getReferencePictureList(ii);
     for (uint32_t jj = 0; isAllEntriesinRPLHasSameSignFlag && jj < rpl->getNumberOfActivePictures(); jj++)
@@ -2084,57 +2149,6 @@ void EncLib::xInitRPL(SPS &sps)
   sps.setAllActiveRplEntriesHasSameSignFlag(isAllEntriesinRPLHasSameSignFlag);
 }
 
-void EncLib::getActiveRefPicListNumForPOC(const SPS *sps, int POCCurr, int GOPid, uint32_t *activeL0, uint32_t *activeL1)
-{
-  if (m_isLowDelay)  //Only for RA
-  {
-    *activeL0 = *activeL1 = 0;
-    return;
-  }
-  uint32_t rpl0Idx = GOPid;
-  uint32_t rpl1Idx = GOPid;
-
-  int fullListNum = m_iGOPSize;
-  int partialListNum = getRPLCandidateSize(0) - m_iGOPSize;
-  int extraNum = fullListNum;
-  if (m_isLowDelay)
-  {
-    if (POCCurr < (2 * m_iGOPSize + 2))
-    {
-      int candidateIdx = (POCCurr + m_iGOPSize - 1 >= fullListNum + partialListNum) ? GOPid : POCCurr + m_iGOPSize - 1;
-      rpl0Idx = candidateIdx;
-      rpl1Idx = candidateIdx;
-    }
-    else
-    {
-      rpl0Idx = (POCCurr%m_iGOPSize == 0) ? m_iGOPSize - 1 : POCCurr%m_iGOPSize - 1;
-      rpl1Idx = (POCCurr%m_iGOPSize == 0) ? m_iGOPSize - 1 : POCCurr%m_iGOPSize - 1;
-    }
-    extraNum = fullListNum + partialListNum;
-  }
-  for (; extraNum<fullListNum + partialListNum; extraNum++)
-  {
-    if (m_intraPeriod > 0 && getDecodingRefreshType() > 0)
-    {
-      int POCIndex = POCCurr % m_intraPeriod;
-      if (POCIndex == 0)
-      {
-        POCIndex = m_intraPeriod;
-      }
-      if (POCIndex == m_RPLList0[extraNum].m_POC)
-      {
-        rpl0Idx = extraNum;
-        rpl1Idx = extraNum;
-        extraNum++;
-      }
-    }
-  }
-
-  const ReferencePictureList *rpl0 = sps->getRPLList0()->getReferencePictureList(rpl0Idx);
-  *activeL0 = rpl0->getNumberOfActivePictures();
-  const ReferencePictureList *rpl1 = sps->getRPLList1()->getReferencePictureList(rpl1Idx);
-  *activeL1 = rpl1->getNumberOfActivePictures();
-}
 
 void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, int ltPoc)
 {
@@ -2144,8 +2158,21 @@ void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, in
     POCCurr++;
   }
 
-  slice->setRPL0idx(GOPid);
-  slice->setRPL1idx(GOPid);
+  const RPLList* rplLists[2];
+  bool codeRplInSH = getRplOfDepLayerInSh();
+  int RPLIdx = GOPid;
+  if (codeRplInSH)
+  {
+    rplLists[0] = getRPLList(0);
+    rplLists[1] = getRPLList(1);
+    slice->setRPL0idx(-1);
+    slice->setRPL1idx(-1);
+  }
+  else
+  {
+    rplLists[0] = slice->getSPS()->getRPLList(0);
+    rplLists[1] = slice->getSPS()->getRPLList(1);
+  }
 
   int fullListNum = m_iGOPSize;
   int partialListNum = getRPLCandidateSize(0) - m_iGOPSize;
@@ -2154,7 +2181,7 @@ void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, in
   int rplPeriod = m_intraPeriod;
   if( rplPeriod < 0 )  //Need to check if it is low delay or RA but with no RAP
   {
-    if( slice->getSPS()->getRPLList0()->getReferencePictureList(1)->getRefPicIdentifier(0) * slice->getSPS()->getRPLList1()->getReferencePictureList(1)->getRefPicIdentifier(0) < 0)
+    if (rplLists[0]->getReferencePictureList(1)->getRefPicIdentifier(0) * rplLists[1]->getReferencePictureList(1)->getRefPicIdentifier(0) < 0)
     {
       rplPeriod = m_iGOPSize * 2;
     }
@@ -2166,13 +2193,11 @@ void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, in
     if (currPOCsinceLastIDR < (2 * m_iGOPSize + 2))
     {
       int candidateIdx = (currPOCsinceLastIDR + m_iGOPSize - 1 >= fullListNum + partialListNum) ? GOPid : currPOCsinceLastIDR + m_iGOPSize - 1;
-      slice->setRPL0idx(candidateIdx);
-      slice->setRPL1idx(candidateIdx);
+      RPLIdx = candidateIdx;
     }
     else
     {
-      slice->setRPL0idx((POCCurr%m_iGOPSize == 0) ? m_iGOPSize - 1 : POCCurr%m_iGOPSize - 1);
-      slice->setRPL1idx((POCCurr%m_iGOPSize == 0) ? m_iGOPSize - 1 : POCCurr%m_iGOPSize - 1);
+      RPLIdx = (POCCurr % m_iGOPSize == 0) ? m_iGOPSize - 1 : POCCurr % m_iGOPSize - 1;
     }
     extraNum = fullListNum + partialListNum;
   }
@@ -2187,8 +2212,7 @@ void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, in
       }
       if (POCIndex == m_RPLList0[extraNum].m_POC)
       {
-        slice->setRPL0idx(extraNum);
-        slice->setRPL1idx(extraNum);
+        RPLIdx = extraNum;
         extraNum++;
       }
     }
@@ -2208,34 +2232,35 @@ void EncLib::selectReferencePictureList(Slice* slice, int POCCurr, int GOPid, in
       int numRPLCandidates = getRPLCandidateSize(0);
       if (POCCurr < numRPLCandidates - m_iGOPSize + 2)
       {
-        slice->setRPL0idx(POCCurr + m_iGOPSize - 2);
-        slice->setRPL1idx(POCCurr + m_iGOPSize - 2);
+        RPLIdx = POCCurr + m_iGOPSize - 2;
       }
       else
       {
         if (POCCurr%m_iGOPSize == 0)
         {
-          slice->setRPL0idx(m_iGOPSize - 2);
-          slice->setRPL1idx(m_iGOPSize - 2);
+          RPLIdx = m_iGOPSize - 2;
         }
         else if (POCCurr%m_iGOPSize == 1)
         {
-          slice->setRPL0idx(m_iGOPSize - 1);
-          slice->setRPL1idx(m_iGOPSize - 1);
+          RPLIdx = m_iGOPSize - 1;
         }
         else
         {
-          slice->setRPL0idx(POCCurr % m_iGOPSize - 2);
-          slice->setRPL1idx(POCCurr % m_iGOPSize - 2);
+          RPLIdx = POCCurr % m_iGOPSize - 2;
         }
       }
     }
   }
 
-  const ReferencePictureList *rpl0 = (slice->getSPS()->getRPLList0()->getReferencePictureList(slice->getRPL0idx()));
-  const ReferencePictureList *rpl1 = (slice->getSPS()->getRPLList1()->getReferencePictureList(slice->getRPL1idx()));
-  *slice->getRPL0() = *rpl0;
-  *slice->getRPL1() = *rpl1;
+  * slice->getRPL0() = *rplLists[0]->getReferencePictureList(RPLIdx);
+  *slice->getRPL1() = *rplLists[1]->getReferencePictureList(RPLIdx);
+
+  if (!codeRplInSH)
+  {
+    slice->setRPL0idx(RPLIdx);
+    slice->setRPL1idx(RPLIdx);
+  }
+
 }
 
 

[Vadim Seregin]

m_layerId can't be used as an argument here, the function declaration is getInterLayerRefIdc( uint32_t layerIdx, uint32_t refLayerIdx ) and m_layerId is not necessarily equal to layerIdx. This code crashes VTM encoder when m_layerId is not equal to layerIdx.

m_layerId argument should be replaced with m_vps->getGeneralLayerIdx( m_layerId ), which produces the correct layerIdx for a given m_layerId

[Fabrice URBAN]

Thank for pointing that out. I fixed this in MR !2496 (merged)