codec/processing/src/backgrounddetection/BackgroundDetection.cpp

/*!
 * \copy
 *     Copyright (c)  2013, Cisco Systems
 *     All rights reserved.
 *
 *     Redistribution and use in source and binary forms, with or without
 *     modification, are permitted provided that the following conditions
 *     are met:
 *
 *        * Redistributions of source code must retain the above copyright
 *          notice, this list of conditions and the following disclaimer.
 *
 *        * Redistributions in binary form must reproduce the above copyright
 *          notice, this list of conditions and the following disclaimer in
 *          the documentation and/or other materials provided with the
 *          distribution.
 *
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *     COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *     BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 *     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *     ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *     POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "BackgroundDetection.h"

WELSVP_NAMESPACE_BEGIN

#define LOG2_BGD_OU_SIZE    (4)
#define LOG2_BGD_OU_SIZE_UV (LOG2_BGD_OU_SIZE-1)
#define BGD_OU_SIZE         (1<<LOG2_BGD_OU_SIZE)
#define BGD_OU_SIZE_UV      (BGD_OU_SIZE>>1)
#define BGD_THD_SAD         (2*BGD_OU_SIZE*BGD_OU_SIZE)
#define BGD_THD_ASD_UV      (4*BGD_OU_SIZE_UV)
#define LOG2_MB_SIZE        (4)
#define OU_SIZE_IN_MB       (BGD_OU_SIZE >> 4)
#define Q_FACTOR            (8)
#define BGD_DELTA_QP_THD    (3)

#define OU_LEFT         (0x01)
#define OU_RIGHT        (0x02)
#define OU_TOP          (0x04)
#define OU_BOTTOM       (0x08)

CBackgroundDetection::CBackgroundDetection (int32_t iCpuFlag) {
  m_eMethod = METHOD_BACKGROUND_DETECTION;
  WelsMemset (&m_BgdParam, 0, sizeof (m_BgdParam));
  m_iLargestFrameSize = 0;
}

CBackgroundDetection::~CBackgroundDetection() {
  WelsFree (m_BgdParam.pOU_array);
}

EResult CBackgroundDetection::Process (int32_t iType, SPixMap* pSrcPixMap, SPixMap* pRefPixMap) {
  EResult eReturn = RET_INVALIDPARAM;

  if (pSrcPixMap == NULL || pRefPixMap == NULL)
    return eReturn;

  m_BgdParam.pCur[0] = (uint8_t*)pSrcPixMap->pPixel[0];
  m_BgdParam.pCur[1] = (uint8_t*)pSrcPixMap->pPixel[1];
  m_BgdParam.pCur[2] = (uint8_t*)pSrcPixMap->pPixel[2];
  m_BgdParam.pRef[0] = (uint8_t*)pRefPixMap->pPixel[0];
  m_BgdParam.pRef[1] = (uint8_t*)pRefPixMap->pPixel[1];
  m_BgdParam.pRef[2] = (uint8_t*)pRefPixMap->pPixel[2];
  m_BgdParam.iBgdWidth = pSrcPixMap->sRect.iRectWidth;
  m_BgdParam.iBgdHeight = pSrcPixMap->sRect.iRectHeight;
  m_BgdParam.iStride[0] = pSrcPixMap->iStride[0];
  m_BgdParam.iStride[1] = pSrcPixMap->iStride[1];
  m_BgdParam.iStride[2] = pSrcPixMap->iStride[2];

  int32_t iCurFrameSize = m_BgdParam.iBgdWidth * m_BgdParam.iBgdHeight;
  if (m_BgdParam.pOU_array == NULL || iCurFrameSize > m_iLargestFrameSize) {
    WelsFree (m_BgdParam.pOU_array);
    m_BgdParam.pOU_array = AllocateOUArrayMemory (m_BgdParam.iBgdWidth, m_BgdParam.iBgdHeight);
    m_iLargestFrameSize = iCurFrameSize;
  }

  if (m_BgdParam.pOU_array == NULL)
    return eReturn;

  BackgroundDetection (&m_BgdParam);

  return RET_SUCCESS;
}

EResult CBackgroundDetection::Set (int32_t iType, void* pParam) {
  if (pParam == NULL) {
    return RET_INVALIDPARAM;
  }

  SBGDInterface* pInterface = (SBGDInterface*)pParam;

  m_BgdParam.pBackgroundMbFlag = (int8_t*)pInterface->pBackgroundMbFlag;
  m_BgdParam.pCalcRes = pInterface->pCalcRes;

  return RET_SUCCESS;
}

inline SBackgroundOU* CBackgroundDetection::AllocateOUArrayMemory (int32_t iWidth, int32_t iHeight) {
  int32_t       iMaxOUWidth     = (BGD_OU_SIZE - 1 + iWidth) >> LOG2_BGD_OU_SIZE;
  int32_t       iMaxOUHeight    = (BGD_OU_SIZE - 1 + iHeight) >> LOG2_BGD_OU_SIZE;
  return (SBackgroundOU*)WelsMalloc (iMaxOUWidth * iMaxOUHeight * sizeof (SBackgroundOU));
}

void CBackgroundDetection::GetOUParameters (SVAACalcResult* sVaaCalcInfo, int32_t iMbIndex, int32_t iMbWidth,
    SBackgroundOU* pBgdOU) {
  int32_t       iSubSD[4];
  uint8_t       iSubMAD[4];
  int32_t       iSubSAD[4];

  uint8_t (*pMad8x8)[4];
  int32_t (*pSad8x8)[4];
  int32_t (*pSd8x8)[4];

  pSad8x8 = sVaaCalcInfo->pSad8x8;
  pMad8x8 = sVaaCalcInfo->pMad8x8;
  pSd8x8  = sVaaCalcInfo->pSumOfDiff8x8;

  iSubSAD[0] = pSad8x8[iMbIndex][0];
  iSubSAD[1] = pSad8x8[iMbIndex][1];
  iSubSAD[2] = pSad8x8[iMbIndex][2];
  iSubSAD[3] = pSad8x8[iMbIndex][3];

  iSubSD[0] = pSd8x8[iMbIndex][0];
  iSubSD[1] = pSd8x8[iMbIndex][1];
  iSubSD[2] = pSd8x8[iMbIndex][2];
  iSubSD[3] = pSd8x8[iMbIndex][3];

  iSubMAD[0] = pMad8x8[iMbIndex][0];
  iSubMAD[1] = pMad8x8[iMbIndex][1];
  iSubMAD[2] = pMad8x8[iMbIndex][2];
  iSubMAD[3] = pMad8x8[iMbIndex][3];

  pBgdOU->iSD   = iSubSD[0] + iSubSD[1] + iSubSD[2] + iSubSD[3];
  pBgdOU->iSAD  = iSubSAD[0] + iSubSAD[1] + iSubSAD[2] + iSubSAD[3];
  pBgdOU->iSD   = WELS_ABS (pBgdOU->iSD);

  // get the max absolute difference (MAD) of OU and min value of the MAD of sub-blocks of OU
  pBgdOU->iMAD = WELS_MAX (WELS_MAX (iSubMAD[0], iSubMAD[1]), WELS_MAX (iSubMAD[2], iSubMAD[3]));
  pBgdOU->iMinSubMad = WELS_MIN (WELS_MIN (iSubMAD[0], iSubMAD[1]), WELS_MIN (iSubMAD[2], iSubMAD[3]));

  // get difference between the max and min SD of the SDs of sub-blocks of OU
  pBgdOU->iMaxDiffSubSd = WELS_MAX (WELS_MAX (iSubSD[0], iSubSD[1]), WELS_MAX (iSubSD[2], iSubSD[3])) -
                          WELS_MIN (WELS_MIN (iSubSD[0], iSubSD[1]), WELS_MIN (iSubSD[2], iSubSD[3]));
}

void CBackgroundDetection::ForegroundBackgroundDivision (vBGDParam* pBgdParam) {
  int32_t iPicWidthInOU         = pBgdParam->iBgdWidth  >> LOG2_BGD_OU_SIZE;
  int32_t iPicHeightInOU        = pBgdParam->iBgdHeight >> LOG2_BGD_OU_SIZE;
  int32_t iPicWidthInMb         = (15 + pBgdParam->iBgdWidth) >> 4;

  SBackgroundOU* pBackgroundOU = pBgdParam->pOU_array;

  for (int32_t j = 0; j < iPicHeightInOU; j ++) {
    for (int32_t i = 0; i < iPicWidthInOU; i++) {
      GetOUParameters (pBgdParam->pCalcRes, (j * iPicWidthInMb + i) << (LOG2_BGD_OU_SIZE - LOG2_MB_SIZE), iPicWidthInMb,
                       pBackgroundOU);

      pBackgroundOU->iBackgroundFlag = 0;
      if (pBackgroundOU->iMAD > 63) {
        pBackgroundOU++;
        continue;
      }
      if ((pBackgroundOU->iMaxDiffSubSd <= pBackgroundOU->iSAD >> 3
           || pBackgroundOU->iMaxDiffSubSd <= (BGD_OU_SIZE * Q_FACTOR))
          && pBackgroundOU->iSAD < (BGD_THD_SAD << 1)) { //BGD_OU_SIZE*BGD_OU_SIZE>>2
        if (pBackgroundOU->iSAD <= BGD_OU_SIZE * Q_FACTOR) {
          pBackgroundOU->iBackgroundFlag = 1;
        } else {
          pBackgroundOU->iBackgroundFlag = pBackgroundOU->iSAD < BGD_THD_SAD ?
                                           (pBackgroundOU->iSD < (pBackgroundOU->iSAD * 3) >> 2) :
                                           (pBackgroundOU->iSD << 1 < pBackgroundOU->iSAD);
        }
      }
      pBackgroundOU++;
    }
  }
}
inline int32_t CBackgroundDetection::CalculateAsdChromaEdge (uint8_t* pOriRef, uint8_t* pOriCur, int32_t iStride) {
  int32_t ASD = 0;
  int32_t idx;
  for (idx = 0; idx < BGD_OU_SIZE_UV; idx++) {
    ASD += *pOriCur - *pOriRef;
    pOriRef += iStride;
    pOriCur += iStride;
  }
  return WELS_ABS (ASD);
}

inline bool CBackgroundDetection::ForegroundDilation23Luma (SBackgroundOU* pBackgroundOU,
    SBackgroundOU* pOUNeighbours[]) {
  SBackgroundOU* pOU_L = pOUNeighbours[0];
  SBackgroundOU* pOU_R = pOUNeighbours[1];
  SBackgroundOU* pOU_U = pOUNeighbours[2];
  SBackgroundOU* pOU_D = pOUNeighbours[3];

  if (pBackgroundOU->iMAD > pBackgroundOU->iMinSubMad << 1) {
    int32_t iMaxNbrForegroundMad;
    int32_t iMaxNbrBackgroundMad;
    int32_t aBackgroundMad[4];
    int32_t aForegroundMad[4];

    aForegroundMad[0] = (pOU_L->iBackgroundFlag - 1) & pOU_L->iMAD;
    aForegroundMad[1] = (pOU_R->iBackgroundFlag - 1) & pOU_R->iMAD;
    aForegroundMad[2] = (pOU_U->iBackgroundFlag - 1) & pOU_U->iMAD;
    aForegroundMad[3] = (pOU_D->iBackgroundFlag - 1) & pOU_D->iMAD;
    iMaxNbrForegroundMad = WELS_MAX (WELS_MAX (aForegroundMad[0], aForegroundMad[1]), WELS_MAX (aForegroundMad[2],
                                     aForegroundMad[3]));

    aBackgroundMad[0] = ((!pOU_L->iBackgroundFlag) - 1) & pOU_L->iMAD;
    aBackgroundMad[1] = ((!pOU_R->iBackgroundFlag) - 1) & pOU_R->iMAD;
    aBackgroundMad[2] = ((!pOU_U->iBackgroundFlag) - 1) & pOU_U->iMAD;
    aBackgroundMad[3] = ((!pOU_D->iBackgroundFlag) - 1) & pOU_D->iMAD;
    iMaxNbrBackgroundMad = WELS_MAX (WELS_MAX (aBackgroundMad[0], aBackgroundMad[1]), WELS_MAX (aBackgroundMad[2],
                                     aBackgroundMad[3]));

    return ((iMaxNbrForegroundMad > pBackgroundOU->iMinSubMad << 2) || (pBackgroundOU->iMAD > iMaxNbrBackgroundMad << 1
            && pBackgroundOU->iMAD <= (iMaxNbrForegroundMad * 3) >> 1));
  }
  return 0;
}

inline bool CBackgroundDetection::ForegroundDilation23Chroma (int8_t iNeighbourForegroundFlags,
    int32_t iStartSamplePos, int32_t iPicStrideUV, vBGDParam* pBgdParam) {
  static const int8_t kaOUPos[4]        = {OU_LEFT, OU_RIGHT, OU_TOP, OU_BOTTOM};
  int32_t       aEdgeOffset[4]          = {0, BGD_OU_SIZE_UV - 1, 0, iPicStrideUV* (BGD_OU_SIZE_UV - 1)};
  int32_t       iStride[4]              = {iPicStrideUV, iPicStrideUV, 1, 1};

  // V component first, high probability because V stands for red color and human skin colors have more weight on this component
  for (int32_t i = 0; i < 4; i++) {
    if (iNeighbourForegroundFlags & kaOUPos[i]) {
      uint8_t* pRefC = pBgdParam->pRef[2] + iStartSamplePos + aEdgeOffset[i];
      uint8_t* pCurC = pBgdParam->pCur[2] + iStartSamplePos + aEdgeOffset[i];
      if (CalculateAsdChromaEdge (pRefC, pCurC, iStride[i]) > BGD_THD_ASD_UV) {
        return 1;
      }
    }
  }
  // U component, which stands for blue color, low probability
  for (int32_t i = 0; i < 4; i++) {
    if (iNeighbourForegroundFlags & kaOUPos[i]) {
      uint8_t* pRefC = pBgdParam->pRef[1] + iStartSamplePos + aEdgeOffset[i];
      uint8_t* pCurC = pBgdParam->pCur[1] + iStartSamplePos + aEdgeOffset[i];
      if (CalculateAsdChromaEdge (pRefC, pCurC, iStride[i]) > BGD_THD_ASD_UV) {
        return 1;
      }
    }
  }

  return 0;
}

inline void CBackgroundDetection::ForegroundDilation (SBackgroundOU* pBackgroundOU, SBackgroundOU* pOUNeighbours[],
    vBGDParam* pBgdParam, int32_t iChromaSampleStartPos) {
  int32_t iPicStrideUV = pBgdParam->iStride[1];
  int32_t iSumNeighBackgroundFlags = pOUNeighbours[0]->iBackgroundFlag + pOUNeighbours[1]->iBackgroundFlag +
                                      pOUNeighbours[2]->iBackgroundFlag + pOUNeighbours[3]->iBackgroundFlag;

  if (pBackgroundOU->iSAD > BGD_OU_SIZE * Q_FACTOR) {
    switch (iSumNeighBackgroundFlags) {
    case 0:
    case 1:
      pBackgroundOU->iBackgroundFlag = 0;
      break;
    case 2:
    case 3:
      pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Luma (pBackgroundOU, pOUNeighbours);

      // chroma component check
      if (pBackgroundOU->iBackgroundFlag == 1) {
        int8_t iNeighbourForegroundFlags = (!pOUNeighbours[0]->iBackgroundFlag) | ((!pOUNeighbours[1]->iBackgroundFlag) << 1)
                                            | ((!pOUNeighbours[2]->iBackgroundFlag) << 2) | ((!pOUNeighbours[3]->iBackgroundFlag) << 3);
        pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Chroma (iNeighbourForegroundFlags, iChromaSampleStartPos,
                                         iPicStrideUV, pBgdParam);
      }
      break;
    default:
      break;
    }
  }
}
inline void CBackgroundDetection::BackgroundErosion (SBackgroundOU* pBackgroundOU, SBackgroundOU* pOUNeighbours[]) {
  if (pBackgroundOU->iMaxDiffSubSd <= (BGD_OU_SIZE * Q_FACTOR)) { //BGD_OU_SIZE*BGD_OU_SIZE>>2
    int32_t iSumNeighBackgroundFlags = pOUNeighbours[0]->iBackgroundFlag + pOUNeighbours[1]->iBackgroundFlag +
                                       pOUNeighbours[2]->iBackgroundFlag + pOUNeighbours[3]->iBackgroundFlag;
    int32_t sumNbrBGsad = (pOUNeighbours[0]->iSAD & (-pOUNeighbours[0]->iBackgroundFlag)) + (pOUNeighbours[2]->iSAD &
                          (-pOUNeighbours[2]->iBackgroundFlag))
                          + (pOUNeighbours[1]->iSAD & (-pOUNeighbours[1]->iBackgroundFlag)) + (pOUNeighbours[3]->iSAD &
                              (-pOUNeighbours[3]->iBackgroundFlag));
    if (pBackgroundOU->iSAD * iSumNeighBackgroundFlags <= (3 * sumNbrBGsad) >> 1) {
      if (iSumNeighBackgroundFlags == 4) {
        pBackgroundOU->iBackgroundFlag = 1;
      } else {
        if ((pOUNeighbours[0]->iBackgroundFlag & pOUNeighbours[1]->iBackgroundFlag)
            || (pOUNeighbours[2]->iBackgroundFlag & pOUNeighbours[3]->iBackgroundFlag)) {
          pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Luma (pBackgroundOU, pOUNeighbours);
        }
      }
    }
  }
}

inline void CBackgroundDetection::SetBackgroundMbFlag (int8_t* pBackgroundMbFlag, int32_t iPicWidthInMb,
    int32_t iBackgroundMbFlag) {
  *pBackgroundMbFlag = iBackgroundMbFlag;
}

inline void CBackgroundDetection::UpperOUForegroundCheck (SBackgroundOU* pCurOU, int8_t* pBackgroundMbFlag,
    int32_t iPicWidthInOU, int32_t iPicWidthInMb) {
  if (pCurOU->iSAD > BGD_OU_SIZE * Q_FACTOR) {
    SBackgroundOU* pOU_L = pCurOU - 1;
    SBackgroundOU* pOU_R = pCurOU + 1;
    SBackgroundOU* pOU_U = pCurOU - iPicWidthInOU;
    SBackgroundOU* pOU_D = pCurOU + iPicWidthInOU;
    if (pOU_L->iBackgroundFlag + pOU_R->iBackgroundFlag + pOU_U->iBackgroundFlag + pOU_D->iBackgroundFlag <= 1) {
      SetBackgroundMbFlag (pBackgroundMbFlag, iPicWidthInMb, 0);
      pCurOU->iBackgroundFlag = 0;
    }
  }
}

void CBackgroundDetection::ForegroundDilationAndBackgroundErosion (vBGDParam* pBgdParam) {
  int32_t iPicStrideUV          = pBgdParam->iStride[1];
  int32_t iPicWidthInOU         = pBgdParam->iBgdWidth  >> LOG2_BGD_OU_SIZE;
  int32_t iPicHeightInOU        = pBgdParam->iBgdHeight >> LOG2_BGD_OU_SIZE;
  int32_t iOUStrideUV           = iPicStrideUV << (LOG2_BGD_OU_SIZE - 1);
  int32_t iPicWidthInMb         = (15 + pBgdParam->iBgdWidth) >> 4;

  SBackgroundOU* pBackgroundOU = pBgdParam->pOU_array;
  int8_t*        pVaaBackgroundMbFlag = (int8_t*)pBgdParam->pBackgroundMbFlag;
  SBackgroundOU* pOUNeighbours[4];//0: left; 1: right; 2: top; 3: bottom

  pOUNeighbours[2]      = pBackgroundOU;//top OU
  for (int32_t j = 0; j < iPicHeightInOU; j ++) {
    int8_t* pRowSkipFlag = pVaaBackgroundMbFlag;
    pOUNeighbours[0]    = pBackgroundOU;//left OU
    pOUNeighbours[3]    = pBackgroundOU + (iPicWidthInOU & ((j == iPicHeightInOU - 1) - 1)); //bottom OU
    for (int32_t i = 0; i < iPicWidthInOU; i++) {
      pOUNeighbours[1] = pBackgroundOU + (i < iPicWidthInOU - 1); //right OU

      if (pBackgroundOU->iBackgroundFlag)
        ForegroundDilation (pBackgroundOU, pOUNeighbours, pBgdParam, j * iOUStrideUV + (i << LOG2_BGD_OU_SIZE_UV));
      else
        BackgroundErosion (pBackgroundOU, pOUNeighbours);

      // check the up OU
      if (j > 1 && i > 0 && i < iPicWidthInOU - 1 && pOUNeighbours[2]->iBackgroundFlag == 1) {
        UpperOUForegroundCheck (pOUNeighbours[2], pRowSkipFlag - OU_SIZE_IN_MB * iPicWidthInMb, iPicWidthInOU, iPicWidthInMb);
      }

      SetBackgroundMbFlag (pRowSkipFlag, iPicWidthInMb, pBackgroundOU->iBackgroundFlag);

      // preparation for the next OU
      pRowSkipFlag += OU_SIZE_IN_MB;
      pOUNeighbours[0] = pBackgroundOU;
      pOUNeighbours[2]++;
      pOUNeighbours[3]++;
      pBackgroundOU++;
    }
    pOUNeighbours[2]      = pBackgroundOU - iPicWidthInOU;
    pVaaBackgroundMbFlag += OU_SIZE_IN_MB * iPicWidthInMb;
  }
}

void CBackgroundDetection::BackgroundDetection (vBGDParam* pBgdParam) {
  // 1st step: foreground/background coarse division
  ForegroundBackgroundDivision (pBgdParam);

  // 2nd step: foreground dilation and background erosion
  ForegroundDilationAndBackgroundErosion (pBgdParam);
}

WELSVP_NAMESPACE_END