source/encoder/dpb.cpp

   1 /*****************************************************************************
   2  * Copyright (C) 2013 x265 project
   3  *
   4  * Authors: Steve Borho <steve@borho.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
  19  *
  20  * This program is also available under a commercial proprietary license.
  21  * For more information, contact us at license @ x265.com.
  22  *****************************************************************************/
  23
  24 #include "common.h"
  25 #include "frame.h"
  26 #include "framedata.h"
  27 #include "picyuv.h"
  28 #include "slice.h"
  29
  30 #include "dpb.h"
  31
  32 using namespace x265;
  33
  34 DPB::~DPB()
  35 {
  36     while (!m_freeList.empty())
  37     {
  38         Frame* curFrame = m_freeList.popFront();
  39         curFrame->destroy();
  40         delete curFrame;
  41     }
  42
  43     while (!m_picList.empty())
  44     {
  45         Frame* curFrame = m_picList.popFront();
  46         curFrame->destroy();
  47         delete curFrame;
  48     }
  49
  50     while (m_picSymFreeList)
  51     {
  52         FrameData* next = m_picSymFreeList->m_freeListNext;
  53         m_picSymFreeList->destroy();
  54
  55         m_picSymFreeList->m_reconPic->destroy();
  56         delete m_picSymFreeList->m_reconPic;
  57
  58         delete m_picSymFreeList;
  59         m_picSymFreeList = next;
  60     }
  61 }
  62
  63 // move unreferenced pictures from picList to freeList for recycle
  64 void DPB::recycleUnreferenced()
  65 {
  66     Frame *iterFrame = m_picList.first();
  67
  68     while (iterFrame)
  69     {
  70         Frame *curFrame = iterFrame;
  71         iterFrame = iterFrame->m_next;
  72         if (!curFrame->m_encData->m_bHasReferences && !curFrame->m_countRefEncoders)
  73         {
  74             curFrame->m_reconRowCount.set(0);
  75             curFrame->m_bChromaExtended = false;
  76
  77             // iterator is invalidated by remove, restart scan
  78             m_picList.remove(*curFrame);
  79             iterFrame = m_picList.first();
  80
  81             m_freeList.pushBack(*curFrame);
  82             curFrame->m_encData->m_freeListNext = m_picSymFreeList;
  83             m_picSymFreeList = curFrame->m_encData;
  84             curFrame->m_encData = NULL;
  85             curFrame->m_reconPic = NULL;
  86         }
  87     }
  88 }
  89
  90 void DPB::prepareEncode(Frame *newFrame)
  91 {
  92     Slice* slice = newFrame->m_encData->m_slice;
  93     slice->m_poc = newFrame->m_poc;
  94
  95     int pocCurr = slice->m_poc;
  96     int type = newFrame->m_lowres.sliceType;
  97     bool bIsKeyFrame = newFrame->m_lowres.bKeyframe;
  98
  99     slice->m_nalUnitType = getNalUnitType(pocCurr, bIsKeyFrame);
 100     if (slice->m_nalUnitType == NAL_UNIT_CODED_SLICE_IDR_W_RADL)
 101         m_lastIDR = pocCurr;
 102     slice->m_lastIDR = m_lastIDR;
 103     slice->m_sliceType = IS_X265_TYPE_B(type) ? B_SLICE : (type == X265_TYPE_P) ? P_SLICE : I_SLICE;
 104
 105     if (type == X265_TYPE_B)
 106     {
 107         // change from _R "referenced" to _N "non-referenced" NAL unit type
 108         switch (slice->m_nalUnitType)
 109         {
 110         case NAL_UNIT_CODED_SLICE_TRAIL_R:
 111             slice->m_nalUnitType = NAL_UNIT_CODED_SLICE_TRAIL_N;
 112             break;
 113         case NAL_UNIT_CODED_SLICE_RADL_R:
 114             slice->m_nalUnitType = NAL_UNIT_CODED_SLICE_RADL_N;
 115             break;
 116         case NAL_UNIT_CODED_SLICE_RASL_R:
 117             slice->m_nalUnitType = NAL_UNIT_CODED_SLICE_RASL_N;
 118             break;
 119         default:
 120             break;
 121         }
 122     }
 123
 124     /* m_bHasReferences starts out as true for non-B pictures, and is set to false
 125      * once no more pictures reference it */
 126     newFrame->m_encData->m_bHasReferences = IS_REFERENCED(newFrame);
 127
 128     m_picList.pushFront(*newFrame);
 129
 130     // Do decoding refresh marking if any
 131     decodingRefreshMarking(pocCurr, slice->m_nalUnitType);
 132
 133     computeRPS(pocCurr, slice->isIRAP(), &slice->m_rps, slice->m_sps->maxDecPicBuffering);
 134
 135     // Mark pictures in m_piclist as unreferenced if they are not included in RPS
 136     applyReferencePictureSet(&slice->m_rps, pocCurr);
 137
 138     slice->m_numRefIdx[0] = X265_MIN(m_maxRefL0, slice->m_rps.numberOfNegativePictures); // Ensuring L0 contains just the -ve POC
 139     slice->m_numRefIdx[1] = X265_MIN(m_maxRefL1, slice->m_rps.numberOfPositivePictures);
 140     slice->setRefPicList(m_picList);
 141
 142     X265_CHECK(slice->m_sliceType != B_SLICE || slice->m_numRefIdx[1], "B slice without L1 references (non-fatal)\n");
 143
 144     if (slice->m_sliceType == B_SLICE)
 145     {
 146         /* TODO: the lookahead should be able to tell which reference picture
 147          * had the least motion residual.  We should be able to use that here to
 148          * select a colocation reference list and index */
 149         slice->m_colFromL0Flag = false;
 150         slice->m_colRefIdx = 0;
 151         slice->m_bCheckLDC = false;
 152     }
 153     else
 154     {
 155         slice->m_bCheckLDC = true;
 156         slice->m_colFromL0Flag = true;
 157         slice->m_colRefIdx = 0;
 158     }
 159     slice->m_sLFaseFlag = (SLFASE_CONSTANT & (1 << (pocCurr % 31))) > 0;
 160
 161     /* Increment reference count of all motion-referenced frames to prevent them
 162      * from being recycled. These counts are decremented at the end of
 163      * compressFrame() */
 164     int numPredDir = slice->isInterP() ? 1 : slice->isInterB() ? 2 : 0;
 165     for (int l = 0; l < numPredDir; l++)
 166     {
 167         for (int ref = 0; ref < slice->m_numRefIdx[l]; ref++)
 168         {
 169             Frame *refpic = slice->m_refPicList[l][ref];
 170             ATOMIC_INC(&refpic->m_countRefEncoders);
 171         }
 172     }
 173 }
 174
 175 void DPB::computeRPS(int curPoc, bool isRAP, RPS * rps, unsigned int maxDecPicBuffer)
 176 {
 177     unsigned int poci = 0, numNeg = 0, numPos = 0;
 178
 179     Frame* iterPic = m_picList.first();
 180
 181     while (iterPic && (poci < maxDecPicBuffer - 1))
 182     {
 183         if ((iterPic->m_poc != curPoc) && iterPic->m_encData->m_bHasReferences)
 184         {
 185             rps->poc[poci] = iterPic->m_poc;
 186             rps->deltaPOC[poci] = rps->poc[poci] - curPoc;
 187             (rps->deltaPOC[poci] < 0) ? numNeg++ : numPos++;
 188             rps->bUsed[poci] = !isRAP;
 189             poci++;
 190         }
 191         iterPic = iterPic->m_next;
 192     }
 193
 194     rps->numberOfPictures = poci;
 195     rps->numberOfPositivePictures = numPos;
 196     rps->numberOfNegativePictures = numNeg;
 197
 198     rps->sortDeltaPOC();
 199 }
 200
 201 /* Marking reference pictures when an IDR/CRA is encountered. */
 202 void DPB::decodingRefreshMarking(int pocCurr, NalUnitType nalUnitType)
 203 {
 204     if (nalUnitType == NAL_UNIT_CODED_SLICE_IDR_W_RADL)
 205     {
 206         /* If the nal_unit_type is IDR, all pictures in the reference picture
 207          * list are marked as "unused for reference" */
 208         Frame* iterFrame = m_picList.first();
 209         while (iterFrame)
 210         {
 211             if (iterFrame->m_poc != pocCurr)
 212                 iterFrame->m_encData->m_bHasReferences = false;
 213             iterFrame = iterFrame->m_next;
 214         }
 215     }
 216     else // CRA or No DR
 217     {
 218         if (m_bRefreshPending && pocCurr > m_pocCRA)
 219         {
 220             /* If the bRefreshPending flag is true (a deferred decoding refresh
 221              * is pending) and the current temporal reference is greater than
 222              * the temporal reference of the latest CRA picture (pocCRA), mark
 223              * all reference pictures except the latest CRA picture as "unused
 224              * for reference" and set the bRefreshPending flag to false */
 225             Frame* iterFrame = m_picList.first();
 226             while (iterFrame)
 227             {
 228                 if (iterFrame->m_poc != pocCurr && iterFrame->m_poc != m_pocCRA)
 229                     iterFrame->m_encData->m_bHasReferences = false;
 230                 iterFrame = iterFrame->m_next;
 231             }
 232
 233             m_bRefreshPending = false;
 234         }
 235         if (nalUnitType == NAL_UNIT_CODED_SLICE_CRA)
 236         {
 237             /* If the nal_unit_type is CRA, set the bRefreshPending flag to true
 238              * and pocCRA to the temporal reference of the current picture */
 239             m_bRefreshPending = true;
 240             m_pocCRA = pocCurr;
 241         }
 242     }
 243
 244     /* Note that the current picture is already placed in the reference list and
 245      * its marking is not changed.  If the current picture has a nal_ref_idc
 246      * that is not 0, it will remain marked as "used for reference" */
 247 }
 248
 249 /** Function for applying picture marking based on the Reference Picture Set */
 250 void DPB::applyReferencePictureSet(RPS *rps, int curPoc)
 251 {
 252     // loop through all pictures in the reference picture buffer
 253     Frame* iterFrame = m_picList.first();
 254     while (iterFrame)
 255     {
 256         if (iterFrame->m_poc != curPoc && iterFrame->m_encData->m_bHasReferences)
 257         {
 258             // loop through all pictures in the Reference Picture Set
 259             // to see if the picture should be kept as reference picture
 260             bool referenced = false;
 261             for (int i = 0; i < rps->numberOfPositivePictures + rps->numberOfNegativePictures; i++)
 262             {
 263                 if (iterFrame->m_poc == curPoc + rps->deltaPOC[i])
 264                 {
 265                     referenced = true;
 266                     break;
 267                 }
 268             }
 269             if (!referenced)
 270                 iterFrame->m_encData->m_bHasReferences = false;
 271         }
 272         iterFrame = iterFrame->m_next;
 273     }
 274 }
 275
 276 /* deciding the nal_unit_type */
 277 NalUnitType DPB::getNalUnitType(int curPOC, bool bIsKeyFrame)
 278 {
 279     if (!curPOC)
 280         return NAL_UNIT_CODED_SLICE_IDR_W_RADL;
 281
 282     if (bIsKeyFrame)
 283         return m_bOpenGOP ? NAL_UNIT_CODED_SLICE_CRA : NAL_UNIT_CODED_SLICE_IDR_W_RADL;
 284
 285     if (m_pocCRA && curPOC < m_pocCRA)
 286         // All leading pictures are being marked as TFD pictures here since
 287         // current encoder uses all reference pictures while encoding leading
 288         // pictures. An encoder can ensure that a leading picture can be still
 289         // decodable when random accessing to a CRA/CRANT/BLA/BLANT picture by
 290         // controlling the reference pictures used for encoding that leading
 291         // picture. Such a leading picture need not be marked as a TFD picture.
 292         return NAL_UNIT_CODED_SLICE_RASL_R;
 293
 294     if (m_lastIDR && curPOC < m_lastIDR)
 295         return NAL_UNIT_CODED_SLICE_RADL_R;
 296
 297     return NAL_UNIT_CODED_SLICE_TRAIL_R;
 298 }