me_epzs_int.c

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/*!
*************************************************************************************
* \file me_epzs_int.c
*
* \brief
*    Motion Estimation using EPZS
*
* \author
*    Main contributors (see contributors.h for copyright, address and affiliation details)
*      - Alexis Michael Tourapis <alexismt@ieee.org>
*      - Athanasios Leontaris    <aleon@dolby.com>
*
*************************************************************************************
*/

#include "contributors.h"

#include <limits.h>

#include "global.h"
#include "image.h"
#include "memalloc.h"
#include "mb_access.h"
#include "refbuf.h"
#include "macroblock.h"
#include "me_distortion.h"
#include "me_epzs.h"
#include "me_epzs_common.h"
#include "mv_search.h"

// Functions

/*!
***********************************************************************
* \brief
*    FAST Motion Estimation using EPZS
*    AMT/HYC
***********************************************************************
*/
int                             //  ==> minimum motion cost after search
EPZSIntPelBlockMotionSearch (Macroblock * currMB,     // <--  current Macroblock
                             MotionVector * pred_mv,  // <--  motion vector predictor in sub-pel units
                             MEBlock * mv_block,      // <--  motion vector information
                             int min_mcost,           // <--  minimum motion cost (cost for center or huge value)
                             int lambda_factor        // <--  lagrangian parameter for determining motion cost
                             )
{
  Slice *currSlice = currMB->p_slice;
  ImageParameters *p_Img = currMB->p_Img;
  InputParameters *p_Inp = currMB->p_Inp;
  EPZSParameters *p_EPZS = currSlice->p_EPZS;
  PicMotionParams *motion = &p_Img->enc_picture->motion;

  int blocktype = mv_block->blocktype;

  int list = mv_block->list;
  int cur_list = list + currMB->list_offset;
  short ref = mv_block->ref_idx;
  MotionVector *mv = &mv_block->mv[list];
  SearchWindow *searchRange = &mv_block->searchRange;
  int mapCenter_x = searchRange->max_x - mv->mv_x;
  int mapCenter_y = searchRange->max_y - mv->mv_y;
  StorablePicture *ref_picture = p_Img->listX[cur_list][ref];

  int lambda_dist = (((lambda_factor) * (2)) >> LAMBDA_ACCURACY_BITS);
  int stopCriterion = p_EPZS->medthres[blocktype] + lambda_dist;
  int *prevSad = &p_EPZS->distortion[cur_list][blocktype - 1][mv_block->pos_x2];
  MotionVector *p_motion = NULL;

  EPZSStructure *searchPatternF = p_EPZS->searchPattern;
  uint16 **EPZSMap = &p_EPZS->EPZSMap[mapCenter_y];
  uint16 *EPZSPoint = &p_EPZS->EPZSMap[searchRange->max_y][searchRange->max_x];

  MotionVector center = pad_MVs (*mv, mv_block);
  MotionVector pred = pad_MVs (*pred_mv, mv_block);
  MotionVector tmp = *mv, cand = center;

  ++p_EPZS->BlkCount;
  if (p_EPZS->BlkCount == 0)
    ++p_EPZS->BlkCount;

  if (p_Inp->EPZSSpatialMem)
  {
#if EPZSREF
    p_motion = &p_EPZS->p_motion[cur_list][ref][blocktype - 1][mv_block->block_y][mv_block->pos_x2];
#else
    p_motion = &p_EPZS->p_motion[cur_list][blocktype - 1][mv_block->block_y][mv_block->pos_x2];
#endif
  }

  // Clear EPZSMap
  // memset(EPZSMap[0],FALSE,searcharray*searcharray);
  // Check median candidate;
  //p_EPZS->EPZSMap[0][0] = p_EPZS->BlkCount;
  *EPZSPoint = p_EPZS->BlkCount;

  //--- initialize motion cost (cost for motion vector) and check ---
  min_mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);

  //--- add residual cost to motion cost ---
  min_mcost += mv_block->computePredFPel (ref_picture, mv_block, INT_MAX, &cand);

  // Additional threshold for ref>0
  //if ((ref > 0 && currSlice->structure == FRAME) && (*prevSad < imin (p_EPZS->medthres[blocktype] + lambda_dist, min_mcost))) 
  if ((ref > 0 && currSlice->structure == FRAME) && 
    ((*prevSad < imin (p_EPZS->medthres[blocktype] + lambda_dist, min_mcost)) || (*prevSad * 8 < min_mcost)))
  {
#if EPZSREF
    if (p_Inp->EPZSSpatialMem)
#else 
    if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
    {
      *p_motion = tmp;
    }
    return min_mcost;
  }

  //! If p_EPZS->medthres satisfied, then terminate, otherwise generate Predictors
  //! Condition could be strengthened by consideration distortion of adjacent partitions.
  if (min_mcost > stopCriterion)
  {
    SPoint *p_EPZS_point = p_EPZS->predictor->point;
    Boolean checkMedian = FALSE;
    int second_mcost = INT_MAX;

    int prednum = 5;
    int conditionEPZS;
    MotionVector tmp2 = {0, 0}, tmv;
    int pos, mcost;
    short invalid_refs = 0;

    stopCriterion = EPZSDetermineStopCriterion (p_EPZS, prevSad, mv_block, lambda_dist);

    if (min_mcost < stopCriterion >> 1)
    {
#if EPZSREF
      if (p_Inp->EPZSSpatialMem)
#else 
      if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
      {
        *p_motion = tmp;
      }

      return min_mcost;
    }

    //! Add Spatial Predictors in predictor list.
    //! Scheme adds zero, left, top-left, top, top-right. Note that top-left adds very little
    //! in terms of performance and could be removed with little penalty if any.
    invalid_refs = EPZSSpatialPredictors (p_EPZS, mv_block->block, 
      list, currMB->list_offset, ref, motion->ref_idx[list], motion->mv[list]);

    if (p_Inp->EPZSSpatialMem)
      EPZSSpatialMemPredictors (p_EPZS, mv_block, cur_list, &prednum, ref_picture->size_x >> 2);

    // Temporal predictors
    if (p_Inp->EPZSTemporal)
    {
      EPZSTemporalPredictors (currMB, ref_picture, p_EPZS, mv_block, &prednum, stopCriterion, min_mcost);
    }

    //! Window Size Based Predictors
    //! Basically replaces a Hierarchical ME concept and helps escaping local minima, or
    //! determining large motion variations.
    //! Following predictors can be adjusted further (i.e. removed, conditioned etc)
    //! based on distortion, correlation of adjacent MVs, complexity etc. These predictors
    //! and their conditioning could also be moved after all other predictors have been
    //! tested. Adaptation could also be based on type of material and coding mode (i.e.
    //! field/frame coding,MBAFF etc considering the higher dependency with opposite parity field
    //conditionEPZS = ((min_mcost > stopCriterion)
    // && (p_Inp->EPZSFixed > 1 || (p_Inp->EPZSFixed && currSlice->slice_type == P_SLICE)));
    //conditionEPZS = ((ref == 0) && (min_mcost > stopCriterion)
    //&& (p_Inp->EPZSFixed > 1 || (p_Inp->EPZSFixed && currSlice->slice_type == P_SLICE)));
    //conditionEPZS = ((min_mcost > stopCriterion) && ((ref < 2 && blocktype < 4)
    conditionEPZS = ((min_mcost > 3 * stopCriterion) && ((ref < 2 && blocktype < 4) || (ref < 1 && blocktype == 4)
      || ((currSlice->structure != FRAME || currMB->list_offset) && ref < 3))
      && (p_Inp->EPZSFixed > 1 || (p_Inp->EPZSFixed && currSlice->slice_type == P_SLICE)));

    if (conditionEPZS)
      EPZSWindowPredictors (mv, p_EPZS->predictor, &prednum, 
      (invalid_refs > 2) && (ref < 1 + (currSlice->structure != FRAME || currMB->list_offset)) 
      ? p_EPZS->window_predictor_ext : p_EPZS->window_predictor);

    //! Blocktype/Reference dependent predictors.
    //! Since already mvs for other blocktypes/references have been computed, we can reuse
    //! them in order to easier determine the optimal point. Use of predictors could depend
    //! on cost,
    //conditionEPZS = (ref == 0 || (ref > 0 && min_mcost > stopCriterion) || currSlice->structure != FRAME || currMB->list_offset);
    conditionEPZS = (ref == 0 || (ref > 0 && min_mcost > 2 * stopCriterion));

    if (conditionEPZS && currMB->mbAddrX != 0 && p_Inp->EPZSBlockType)
      EPZSBlockTypePredictorsMB (currSlice, mv_block, p_EPZS_point, &prednum);

    //! Check all predictors
    for (pos = 0; pos < prednum; ++pos)
    {
      tmv = p_EPZS_point[pos].motion;
      //if (((iabs (tmv.mv_x - mv->mv_x) > searchRange->max_x || iabs (tmv.mv_y - mv->mv_y) > searchRange->max_y)) && (tmv.mv_x || tmv.mv_y))
      if ((iabs (tmv.mv_x - mv->mv_x) - searchRange->max_x <= 0) && (iabs (tmv.mv_y - mv->mv_y) - searchRange->max_y <= 0))
      {
        EPZSPoint = &EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x];
        if (*EPZSPoint != p_EPZS->BlkCount)
        {
          *EPZSPoint = p_EPZS->BlkCount;
          cand = pad_MVs (tmv, mv_block);

          //--- set motion cost (cost for motion vector) and check ---
          mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);

          if (mcost < second_mcost)
          {
            mcost += mv_block->computePredFPel (ref_picture, mv_block, second_mcost - mcost, &cand);

            //--- check if motion cost is less than minimum cost ---
            if (mcost < min_mcost)
            {
              tmp2 = tmp;
              tmp = tmv;
              second_mcost = min_mcost;
              min_mcost = mcost;
              checkMedian = TRUE;
            }
            //else if (mcost < second_mcost && (tmp.mv_x != tmv.mv_x || tmp.mv_y != tmv.mv_y))
            else if (mcost < second_mcost)
            {
              tmp2 = tmv;
              second_mcost = mcost;
              checkMedian = TRUE;
            }
          }
        }
      }
    }

    if ((ref > 0 && currSlice->structure == FRAME) && (*prevSad * 3 < min_mcost))
    {  
#if EPZSREF
      if (p_Inp->EPZSSpatialMem)
#else 
      if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
      {
        *p_motion = tmp;
      }
      return min_mcost;
    }

    //! Refine using EPZS pattern if needed
    //! Note that we are using a conservative threshold method. Threshold
    //! could be tested after checking only a certain number of predictors
    //! instead of the full set. Code could be easily modified for this task.
    if (min_mcost > stopCriterion)
    {
      const int mv_range = 10;
      int patternStop = 0, pointNumber = 0, checkPts, nextLast = 0;
      int totalCheckPts = 0, motionDirection = 0;

      //! Adapt pattern based on different conditions.
      if (p_Inp->EPZSPattern != 0)
      {
        if ((min_mcost < stopCriterion + ((3 * p_EPZS->medthres[blocktype]) >> 1)))
        {
          if ((tmp.mv_x == 0 && tmp.mv_y == 0) 
            || (iabs (tmp.mv_x - mv->mv_x) < (mv_range) && iabs (tmp.mv_y - mv->mv_y) < (mv_range)))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else if (ref > 0 && blocktype != 1)
          searchPatternF = p_Img->square;
        else
          searchPatternF = p_EPZS->searchPattern;
      }

      //! center on best predictor
      center = tmp;

      for (;;)
      {
        totalCheckPts = searchPatternF->searchPoints;
        do
        {
          checkPts = totalCheckPts;
          do
          {
            tmv = add_MVs (center, &(searchPatternF->point[pointNumber].motion));

            if (((iabs (tmv.mv_x - mv->mv_x) - searchRange->max_x) <= 0) && ((iabs (tmv.mv_y - mv->mv_y) - searchRange->max_y) <= 0))
            {
              EPZSPoint = &EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x];
              if (*EPZSPoint != p_EPZS->BlkCount)
              {
                *EPZSPoint = p_EPZS->BlkCount;
                cand = pad_MVs (tmv, mv_block);

                mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);

                if (mcost < min_mcost)
                {
                  mcost += mv_block->computePredFPel (ref_picture, mv_block, min_mcost - mcost, &cand);

                  if (mcost < min_mcost)
                  {
                    tmp = tmv;
                    min_mcost = mcost;
                    motionDirection = pointNumber;
                  }
                }
              }
            }
            ++pointNumber;
            if (pointNumber >= searchPatternF->searchPoints)
              pointNumber -= searchPatternF->searchPoints;
            checkPts--;
          }
          while (checkPts > 0);

          if (nextLast || ((tmp.mv_x == center.mv_x) && (tmp.mv_y == center.mv_y)))
          {
            patternStop = searchPatternF->stopSearch;
            searchPatternF = searchPatternF->nextpattern;
            totalCheckPts = searchPatternF->searchPoints;
            nextLast = searchPatternF->nextLast;
            motionDirection = 0;
            pointNumber = 0;
          }
          else
          {
            totalCheckPts = searchPatternF->point[motionDirection].next_points;
            pointNumber = searchPatternF->point[motionDirection].start_nmbr;
            center = tmp;
          }
        }
        while (patternStop != 1);

        if ((ref > 0) && (currSlice->structure == FRAME) 
          && ((4 * *prevSad < min_mcost) || ((3 * *prevSad < min_mcost) && (*prevSad <= stopCriterion))))
        {
          *mv = tmp;
#if EPZSREF
          if (p_Inp->EPZSSpatialMem)
#else  
          if (p_Inp->EPZSSpatialMem && ref == 0)
#endif  
          {
            *p_motion = tmp;
          }

          return min_mcost;
        }

        //! Check Second best predictor with EPZS pattern
        conditionEPZS = (checkMedian == TRUE) 
          && (ref == 0 || (ref > 0 && min_mcost < 2 * *prevSad))
          && (min_mcost > (( 3 * stopCriterion) >> 1)) && (p_Inp->EPZSDual > 0);

        if (!conditionEPZS)
          break;

        pointNumber = 0;
        patternStop = 0;
        motionDirection = 0;
        nextLast = 0;

        if ((tmp.mv_x == 0 && tmp.mv_y == 0) || (tmp.mv_x == mv->mv_x && tmp.mv_y == mv->mv_y))
        {
          if (iabs (tmp.mv_x - mv->mv_x) < (mv_range) && iabs (tmp.mv_y - mv->mv_y) < (mv_range))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else
          searchPatternF = p_EPZS->searchPatternD;

        //! Second best. Note that following code is identical as for best predictor.
        center = tmp2;
        checkMedian = FALSE;
      }
    }
  }

  if ((ref == 0) || (*prevSad > min_mcost))
    *prevSad = min_mcost;
#if EPZSREF
  if (p_Inp->EPZSSpatialMem)
#else  
  if (p_Inp->EPZSSpatialMem && ref == 0)
#endif  
  {
    *p_motion = tmp;
    //printf("value %d %d %d %d\n", p_motion->mv_x, p_motion->mv_y, p_motion[cur_list][ref][0][0][0].mv_x, p_motion[list + list_offset][ref][0][0][0].mv_y);
    //printf("xxxxx %d %d %d %d\n", p_motion->mv_x, p_motion->mv_y, p_motion[cur_list][ref][blocktype - 1][mv_block->block_y][pic_pix_x2].mv_x, p_motion[cur_list][ref][blocktype - 1][mv_block->block_y][pic_pix_x2].mv_y);
  }

  *mv = tmp;

  return min_mcost;
}

/*!
***********************************************************************
* \brief
*    FAST Motion Estimation using EPZS
*    AMT/HYC
***********************************************************************
*/
int                             //  ==> minimum motion cost after search
EPZSIntPelBlockMotionSearchSubMB (Macroblock * currMB,  // <--  current Macroblock
                                  MotionVector * pred_mv, // <--  motion vector predictor in sub-pel units
                                  MEBlock * mv_block, // <--  motion vector information
                                  int min_mcost,  // <--  minimum motion cost (cost for center or huge value)
                                  int lambda_factor // <--  lagrangian parameter for determining motion cost
                                  )
{
  Slice *currSlice = currMB->p_slice;
  ImageParameters *p_Img = currMB->p_Img;
  InputParameters *p_Inp = currMB->p_Inp;
  EPZSParameters *p_EPZS = currSlice->p_EPZS;
  PicMotionParams *motion = &p_Img->enc_picture->motion;

  int blocktype = mv_block->blocktype;
  int list = mv_block->list;
  int cur_list = list + currMB->list_offset;
  short ref = mv_block->ref_idx;
  StorablePicture *ref_picture = p_Img->listX[cur_list][ref];

  MotionVector *mv = &mv_block->mv[list];
  MotionVector center = pad_MVs (*mv, mv_block);
  MotionVector cand = center;
  MotionVector pred = pad_MVs (*pred_mv, mv_block);
  MotionVector tmp = *mv;
  SearchWindow *searchRange = &mv_block->searchRange;
  int mapCenter_x = searchRange->max_x - mv->mv_x;
  int mapCenter_y = searchRange->max_y - mv->mv_y;

  short pic_pix_x2 = mv_block->pos_x2;

  int lambda_dist = (((lambda_factor) * (3)) >> LAMBDA_ACCURACY_BITS);
  int stopCriterion = p_EPZS->medthres[blocktype] + lambda_dist;
  int *prevSad = &p_EPZS->distortion[cur_list][blocktype - 1][pic_pix_x2];
  MotionVector *p_motion = NULL;

  EPZSStructure *searchPatternF = p_EPZS->searchPattern;
  uint16 **EPZSMap = &p_EPZS->EPZSMap[mapCenter_y];

  ++p_EPZS->BlkCount;
  if (p_EPZS->BlkCount == 0)
    ++p_EPZS->BlkCount;

  if (p_Inp->EPZSSpatialMem)
  {
#if EPZSREF
    p_motion = &p_EPZS->p_motion[cur_list][ref][blocktype - 1][mv_block->block_y][pic_pix_x2];
#else 
    p_motion = &p_EPZS->p_motion[cur_list][blocktype - 1][mv_block->block_y][pic_pix_x2];
#endif 
  }

  // Clear p_EPZS->EPZSMap
  // memset(p_EPZS->EPZSMap[0],FALSE,searcharray*searcharray);
  // Check median candidate;
  //p_EPZS->EPZSMap[0][0] = p_EPZS->BlkCount;
  p_EPZS->EPZSMap[searchRange->max_y][searchRange->max_x] = p_EPZS->BlkCount;

  //--- initialize motion cost (cost for motion vector) and check ---
  min_mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);

  //--- add residual cost to motion cost ---
  min_mcost += mv_block->computePredFPel (ref_picture, mv_block, INT_MAX, &cand);

  // Additional threshold for ref>0
  if ((ref > 0 && currSlice->structure == FRAME) && 
    ((*prevSad < imin (p_EPZS->medthres[blocktype] + lambda_dist, min_mcost)) || (*prevSad * 6 < min_mcost)))
  {
#if EPZSREF
    if (p_Inp->EPZSSpatialMem)
#else 
    if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
    {
      *p_motion = tmp;
    }
    return min_mcost;
  }


  //! If p_EPZS->medthres satisfied, then terminate, otherwise generate Predictors
  //! Condition could be strengthened by consideration distortion of adjacent partitions.
  if (min_mcost > stopCriterion)
  {
    SPoint *p_EPZS_point = p_EPZS->predictor->point;
    Boolean checkMedian = FALSE;
    int second_mcost = INT_MAX;
    int prednum = 5;
    int conditionEPZS;

    MotionVector tmv, tmp2 = {0,0};
    int pos, mcost;

    stopCriterion = EPZSDetermineStopCriterion (p_EPZS, prevSad, mv_block, lambda_dist);

    if (min_mcost < (stopCriterion >> 1))
    {
#if EPZSREF
      if (p_Inp->EPZSSpatialMem)
#else 
      if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
      {
        *p_motion = tmp;
      }
      return min_mcost;
    }

    //! Add Spatial Predictors in predictor list.
    //! Scheme adds zero, left, top-left, top, top-right. Note that top-left adds very little
    //! in terms of performance and could be removed with little penalty if any.
    EPZSSpatialPredictors (p_EPZS, mv_block->block, list, currMB->list_offset, ref, motion->ref_idx[list], motion->mv[list]);

    if (p_Inp->EPZSSpatialMem)
      EPZSSpatialMemPredictors (p_EPZS, mv_block, cur_list, &prednum, ref_picture->size_x >> 2);

    //! Blocktype/Reference dependent predictors.
    //! Since already mvs for other blocktypes/references have been computed, we can reuse
    //! them in order to easier determine the optimal point. Use of predictors could depend
    //! on cost,
    conditionEPZS = (ref == 0 || (ref > 0 && min_mcost > 2 * stopCriterion));

    if (conditionEPZS && currMB->mbAddrX != 0 && p_Inp->EPZSBlockType)
      EPZSBlockTypePredictors (currSlice, mv_block, p_EPZS_point, &prednum);

    //! Check all predictors
    for (pos = 0; pos < prednum; ++pos)
    {
      tmv = p_EPZS_point[pos].motion;
      //if (((iabs (tmv.mv_x - mv->mv_x) > searchRange->max_x || iabs (tmv.mv_y - mv->mv_y) > searchRange->max_y)) && (tmv.mv_x || tmv.mv_y))
      if ((iabs (tmv.mv_x - mv->mv_x) - searchRange->max_x <= 0) && (iabs (tmv.mv_y - mv->mv_y) - searchRange->max_y <= 0))
      {

        if (EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] != p_EPZS->BlkCount)
        {
          EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] = p_EPZS->BlkCount;

          cand = pad_MVs (tmv, mv_block);

          //--- set motion cost (cost for motion vector) and check ---
          mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);

          if (mcost < second_mcost)
          {
            mcost += mv_block->computePredFPel (ref_picture, mv_block, second_mcost - mcost, &cand);

            //--- check if motion cost is less than minimum cost ---
            if (mcost < min_mcost)
            {
              tmp2 = tmp;
              tmp = tmv;
              second_mcost = min_mcost;
              min_mcost = mcost;
              checkMedian = TRUE;
            }
            //else if (mcost < second_mcost && (tmp.mv_x != tmv.mv_x || tmp.mv_y != tmv.mv_y))
            else if (mcost < second_mcost)
            {
              tmp2 = tmv;
              second_mcost = mcost;
              checkMedian = TRUE;
            }
          }
        }
      }

      if ((ref > 0 && currSlice->structure == FRAME) && (*prevSad * 3 < min_mcost))
      {  
#if EPZSREF
        if (p_Inp->EPZSSpatialMem)
#else 
        if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
        {
          *p_motion = tmp;
        }
        return min_mcost;
      }

      // At this point, let us add an early termination criterion
      // after checking each predictor. This can help speed up a lot.
      if (min_mcost < ((3 * stopCriterion) >> 2))
      {
#if EPZSREF
        if (p_Inp->EPZSSpatialMem)
#else 
        if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
        {
          *p_motion = tmp;
        }
        *mv = tmp;
        return min_mcost;
      }
    }

    //! Refine using EPZS pattern if needed
    //! Note that we are using a conservative threshold method. Threshold
    //! could be tested after checking only a certain number of predictors
    //! instead of the full set. Code could be easily modified for this task.
    if (min_mcost > stopCriterion)
    {
      int patternStop = 0, pointNumber = 0, checkPts, nextLast = 0;
      int totalCheckPts = 0, motionDirection = 0;
      const int mv_range = 12;

      //! Adapt pattern based on different conditions.
      if (p_Inp->EPZSPattern != 0)
      {
        if ((min_mcost < stopCriterion + ((3 * p_EPZS->medthres[blocktype]) >> 1)))
        {
          if ((blocktype == 7)
            || (tmp.mv_x == 0 && tmp.mv_y == 0) || (iabs (tmp.mv_x - mv->mv_x) < (mv_range) && iabs (tmp.mv_y - mv->mv_y) < (mv_range)))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else
          searchPatternF = p_Img->square;
      }

      //! center on best predictor
      center = tmp;
      for (;;)
      {
        totalCheckPts = searchPatternF->searchPoints;
        do
        {
          checkPts = totalCheckPts;
          do
          {
            tmv = add_MVs (center, &(searchPatternF->point[pointNumber].motion));

            if ((iabs (tmv.mv_x - mv->mv_x) <= searchRange->max_x) && (iabs (tmv.mv_y - mv->mv_y) <= searchRange->max_y))
            {
              if (EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] != p_EPZS->BlkCount)
              {
                EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] = p_EPZS->BlkCount;
                cand = pad_MVs(tmv, mv_block);

                mcost = mv_cost (p_Img, lambda_factor, &cand, &pred);
                if (mcost < min_mcost)
                {

                  mcost += mv_block->computePredFPel (ref_picture, mv_block, min_mcost - mcost, &cand);

                  if (mcost < min_mcost)
                  {
                    tmp = tmv;
                    min_mcost = mcost;
                    motionDirection = pointNumber;
                  }
                }
              }
            }
            ++pointNumber;
            if (pointNumber >= searchPatternF->searchPoints)
              pointNumber -= searchPatternF->searchPoints;
            checkPts--;
          }
          while (checkPts > 0);

          if (nextLast || ((tmp.mv_x == center.mv_x) && (tmp.mv_y == center.mv_y)))
          {
            patternStop = searchPatternF->stopSearch;
            searchPatternF = searchPatternF->nextpattern;
            totalCheckPts = searchPatternF->searchPoints;
            nextLast = searchPatternF->nextLast;
            motionDirection = 0;
            pointNumber = 0;
          }
          else
          {
            totalCheckPts = searchPatternF->point[motionDirection].next_points;
            pointNumber = searchPatternF->point[motionDirection].start_nmbr;
            center = tmp;
          }
        }
        while (patternStop != 1);

        if ((ref > 0) && (currSlice->structure == FRAME)
          && ((4 * *prevSad < min_mcost) || ((3 * *prevSad < min_mcost) && (*prevSad <= stopCriterion))))
        {
          *mv = tmp;
#if EPZSREF
          if (p_Inp->EPZSSpatialMem)
#else 
          if (p_Inp->EPZSSpatialMem && ref == 0)
#endif 
          {
            *p_motion = tmp;
          }

          return min_mcost;
        }

        //! Check Second best predictor with EPZS pattern
        conditionEPZS = (checkMedian == TRUE) && (blocktype != 7)
          //conditionEPZS = (checkMedian == TRUE)
          && (ref == 0 || (ref > 0 && min_mcost < 2 * *prevSad))
          && ((currSlice->slice_type == P_SLICE)) && (min_mcost > ((3 * stopCriterion) >> 1)) && (p_Inp->EPZSDual > 0);

        if (!conditionEPZS)
          break;

        pointNumber = 0;
        patternStop = 0;
        motionDirection = 0;
        nextLast = 0;

        if ((tmp.mv_x == 0 && tmp.mv_y == 0) || (tmp.mv_x == mv->mv_x && tmp.mv_y == mv->mv_y))
        {
          if ((blocktype == 7) || (iabs (tmp.mv_x - mv->mv_x) < (mv_range) && iabs (tmp.mv_y - mv->mv_y) < (mv_range)))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else
          searchPatternF = p_EPZS->searchPatternD;

        //! Now consider second best. 
        center = tmp2;
        checkMedian = FALSE;
      }
    }
  }

  if ((ref == 0) || (*prevSad > min_mcost))
    *prevSad = min_mcost;

#if EPZSREF
  if (p_Inp->EPZSSpatialMem)
#else
  if (p_Inp->EPZSSpatialMem && ref == 0)
#endif
  {
    *p_motion = tmp;
  }

  *mv = tmp;

  return min_mcost;
}

/*!
***********************************************************************
* \brief
*    FAST Motion Estimation using EPZS
*    AMT/HYC
***********************************************************************
*/
int                             //  ==> minimum motion cost after search
EPZSIntBiPredBlockMotionSearch (Macroblock * currMB,  // <--  Current Macroblock
                                int list, // <--  reference list
                                MotionVector * pred_mv1,  // <--  motion vector predictor in sub-pel units
                                MotionVector * pred_mv2,  // <--  motion vector predictor in sub-pel units
                                MotionVector * mv1, // <--> in: search center (x|y) / out: motion vector (x|y) - in pel units
                                MotionVector * mv2, // <--> in: search center (x|y) 
                                MEBlock * mv_block, // <--  motion vector information
                                int search_range, // <--  1-d search range in pel units
                                int min_mcost,  // <--  minimum motion cost (cost for center or huge value)
                                int lambda_factor // <--  lagrangian parameter for determining motion cost
                                )
{
  Slice *currSlice = currMB->p_slice;
  ImageParameters *p_Img = currMB->p_Img;
  InputParameters *p_Inp = currMB->p_Inp;
  EPZSParameters *p_EPZS = currSlice->p_EPZS;
  PicMotionParams *motion = &p_Img->enc_picture->motion;

  int blocktype = mv_block->blocktype;
  short ref = mv_block->ref_idx;

  StorablePicture *ref_picture1 = p_Img->listX[list + currMB->list_offset][ref];
  StorablePicture *ref_picture2 = p_Img->listX[(list ^ 1) + currMB->list_offset][0];

  int mapCenter_x = search_range - mv1->mv_x;
  int mapCenter_y = search_range - mv1->mv_y;

  int lambda_dist = (((lambda_factor) * (4)) >> LAMBDA_ACCURACY_BITS);
  int stopCriterion = p_EPZS->medthres[blocktype] + lambda_dist;

  int *prevSad = &p_EPZS->bi_distortion[list + currMB->list_offset][blocktype - 1][mv_block->pos_x2];
  EPZSStructure *searchPatternF = p_EPZS->searchPattern;
  uint16 **EPZSMap = &p_EPZS->EPZSMap[mapCenter_y];

  MotionVector tmp = *mv1;
  MotionVector center1 = pad_MVs (*mv1, mv_block);
  MotionVector center2 = pad_MVs (*mv2, mv_block);
  MotionVector pred1 = pad_MVs (*pred_mv1, mv_block);
  MotionVector pred2 = pad_MVs (*pred_mv2, mv_block);
  MotionVector cand1 = center1;
  MotionVector cand2 = center2;

  ++p_EPZS->BlkCount;
  if (p_EPZS->BlkCount == 0)
    ++p_EPZS->BlkCount;


  // Clear p_EPZS->EPZSMap
  //memset(p_EPZS->EPZSMap[0],FALSE,searcharray*searcharray);
  // Check median candidate;
  //p_EPZS->EPZSMap[0][0] = p_EPZS->BlkCount;
  p_EPZS->EPZSMap[search_range][search_range] = p_EPZS->BlkCount;

  //--- initialize motion cost (cost for motion vector) and check ---
  min_mcost  = mv_cost (p_Img, lambda_factor, &cand1, &pred1);
  min_mcost += mv_cost (p_Img, lambda_factor, &cand2, &pred2);

  //--- add residual cost to motion cost ---
  min_mcost += mv_block->computeBiPredFPel (ref_picture1, ref_picture2, mv_block, INT_MAX, &cand1, &cand2);

  //! If p_EPZS->medthres satisfied, then terminate, otherwise generate Predictors
  if (min_mcost > stopCriterion)
  {
    SPoint *p_EPZS_point = p_EPZS->predictor->point;
    Boolean checkMedian = FALSE;
    int second_mcost = INT_MAX;
    int prednum = 5;
    MotionVector tmv, tmp2 = { 0, 0 };
    int pos, mcost;

    stopCriterion = EPZSDetermineStopCriterion (p_EPZS, prevSad, mv_block, lambda_dist);

    //! Add Spatial Predictors in predictor list.
    //! Scheme adds zero, left, top-left, top, top-right. Note that top-left adds very little
    //! in terms of performance and could be removed with little penalty if any.
    EPZSSpatialPredictors (p_EPZS, mv_block->block, list, currMB->list_offset, ref, motion->ref_idx[list], motion->mv[list]);

    //! Check all predictors
    for (pos = 0; pos < prednum; ++pos)
    {
      tmv = p_EPZS_point[pos].motion;
      //if ((iabs (tmv.mv_x - mv1->mv_x) > search_range || iabs (tmv.mv_y - mv1->mv_y) > search_range) && (tmv.mv_x || tmv.mv_y))
      if (iabs (tmv.mv_x - mv1->mv_x) <= search_range && iabs (tmv.mv_y - mv1->mv_y) <= search_range)
      {
        if (EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] != p_EPZS->BlkCount)
        {
          EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] = p_EPZS->BlkCount;

          cand1 = pad_MVs (tmv, mv_block);

          //--- set motion cost (cost for motion vector) and check ---
          mcost  = mv_cost (p_Img, lambda_factor, &cand1, &pred1);
          mcost += mv_cost (p_Img, lambda_factor, &cand2, &pred2);

          if (mcost >= second_mcost)
            continue;

          mcost += mv_block->computeBiPredFPel (ref_picture1, ref_picture2, mv_block, second_mcost - mcost, &cand1, &cand2);

          //--- check if motion cost is less than minimum cost ---
          if (mcost < min_mcost)
          {
            tmp2 = tmp;
            tmp = tmv;
            second_mcost = min_mcost;
            min_mcost = mcost;
            checkMedian = TRUE;
          }
          //else if (mcost < second_mcost && (tmp.mv_x != tmv.mv_x || tmp.mv_y != tmv.mv_y))
          else if (mcost < second_mcost)
          {
            tmp2 = tmv;
            second_mcost = mcost;
            checkMedian = TRUE;
          }
        }
      }
    }

    //! Refine using EPZS pattern if needed
    //! Note that we are using a conservative threshold method. Threshold
    //! could be tested after checking only a certain number of predictors
    //! instead of the full set. Code could be easily modified for this task.
    if (min_mcost > stopCriterion)
    {
      int conditionEPZS;
      int patternStop = 0, pointNumber = 0, checkPts, nextLast = 0;
      int totalCheckPts = 0, motionDirection = 0;

      const int mv_range = 12;

      //! Adapt pattern based on different conditions.
      if (p_Inp->EPZSPattern != 0)
      {
        if ((min_mcost < stopCriterion + ((4 * p_EPZS->medthres[blocktype]) >> 1)))
        {
          if ((tmp.mv_x == 0 && tmp.mv_y == 0) || (iabs (tmp.mv_x - mv1->mv_x) < (mv_range) && iabs (tmp.mv_y - mv1->mv_y) < (mv_range)))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else if (blocktype > 5 || (ref > 0 && blocktype != 1))
          searchPatternF = p_Img->square;
        else
          searchPatternF = p_EPZS->searchPattern;
      }

      //! center on best predictor
      center1 = tmp;
      for (;;)
      {
        totalCheckPts = searchPatternF->searchPoints;
        do
        {
          checkPts = totalCheckPts;
          do
          {
            tmv = add_MVs (center1, &(searchPatternF->point[pointNumber].motion));

            if ((iabs (tmv.mv_x - mv1->mv_x) <= search_range) && (iabs (tmv.mv_y - mv1->mv_y) <= search_range))
            {
              if (EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] != p_EPZS->BlkCount)
              {
                EPZSMap[tmv.mv_y][mapCenter_x + tmv.mv_x] = p_EPZS->BlkCount;
                cand1 = pad_MVs (tmv, mv_block);

                mcost  = mv_cost (p_Img, lambda_factor, &cand1, &pred1);
                mcost += mv_cost (p_Img, lambda_factor, &cand2, &pred2);

                if (mcost < min_mcost)
                {
                  mcost += mv_block->computeBiPredFPel (ref_picture1, ref_picture2, mv_block, min_mcost - mcost, &cand1, &cand2);

                  if (mcost < min_mcost)
                  {
                    tmp = tmv;
                    min_mcost = mcost;
                    motionDirection = pointNumber;
                  }
                }
              }
            }
            ++pointNumber;
            if (pointNumber >= searchPatternF->searchPoints)
              pointNumber -= searchPatternF->searchPoints;
            checkPts--;
          }
          while (checkPts > 0);

          if (nextLast || ((tmp.mv_x == center1.mv_x) && (tmp.mv_y == center1.mv_y)))
          {
            patternStop = searchPatternF->stopSearch;
            searchPatternF = searchPatternF->nextpattern;
            totalCheckPts = searchPatternF->searchPoints;
            nextLast = searchPatternF->nextLast;
            motionDirection = 0;
            pointNumber = 0;
          }
          else
          {
            totalCheckPts = searchPatternF->point[motionDirection].next_points;
            pointNumber = searchPatternF->point[motionDirection].start_nmbr;
            center1 = tmp;
          }
        }
        while (patternStop != 1);

        //! Check Second best predictor with EPZS pattern
        conditionEPZS = (checkMedian == TRUE) && (blocktype < 5) && (min_mcost > stopCriterion) && (p_Inp->EPZSDual > 0);

        if (!conditionEPZS)
          break;

        pointNumber = 0;
        patternStop = 0;
        motionDirection = 0;
        nextLast = 0;

        if ((tmp.mv_x == 0 && tmp.mv_y == 0) || (tmp.mv_x == mv1->mv_x && tmp.mv_y == mv1->mv_y))
        {
          if (iabs (tmp.mv_x - mv1->mv_x) < (mv_range) && iabs (tmp.mv_y - mv1->mv_y) < (mv_range))
            searchPatternF = p_Img->sdiamond;
          else
            searchPatternF = p_Img->square;
        }
        else
          searchPatternF = p_EPZS->searchPatternD;
        totalCheckPts = searchPatternF->searchPoints;

        //! Second best. Note that following code is identical as for best predictor.
        center1 = tmp2;
        checkMedian = FALSE;
      }
    }
  }

  if (mv_block->iteration_no == 0)
  {
    *prevSad = min_mcost;
  }

  *mv1 = tmp;

  return min_mcost;
}

---

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