text: /*
   * Copyright (c) 2016, Alliance for Open Media. All rights reserved
   *
   * This source code is subject to the terms of the BSD 2 Clause License and
   * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
   * was not distributed with this source code in the LICENSE file, you can
   * obtain it at www.aomedia.org/license/software. If the Alliance for Open
   * Media Patent License 1.0 was not distributed with this source code in the
   * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
   */
  
  #include <limits.h>
  #include <math.h>
  #include <stdio.h>
  
  #include "config/aom_config.h"
  #include "config/aom_dsp_rtcd.h"
  
  #include "aom_dsp/aom_dsp_common.h"
  #include "aom_mem/aom_mem.h"
  #include "aom_ports/mem.h"
  #include "aom_ports/system_state.h"
  
  #include "av1/common/common.h"
  #include "av1/common/mvref_common.h"
  #include "av1/common/onyxc_int.h"
  #include "av1/common/pred_common.h"
  #include "av1/common/reconinter.h"
  
  #include "av1/encoder/encodeframe_utils.h"
  #include "av1/encoder/encoder.h"
  #include "av1/encoder/encodemv.h"
  #include "av1/encoder/mcomp.h"
  #include "av1/encoder/partition_strategy.h"
  #include "av1/encoder/rdopt.h"
  #include "av1/encoder/reconinter_enc.h"
  
  // #define NEW_DIAMOND_SEARCH
  
  // TODO(any): Adaptively adjust the regularization strength based on image size
  // and motion activity instead of using hard-coded values. It seems like we
  // roughly half the lambda for each increase in resolution
  // These are multiplier used to perform regularization in motion compensation
  // when x->mv_cost_type is set to MV_COST_L1.
  // LOWRES
  #define SSE_LAMBDA_LOWRES 2   // Used by mv_cost_err_fn
  #define SAD_LAMBDA_LOWRES 32  // Used by mvsad_err_cost during full pixel search
  // MIDRES
  #define SSE_LAMBDA_MIDRES 0   // Used by mv_cost_err_fn
  #define SAD_LAMBDA_MIDRES 15  // Used by mvsad_err_cost during full pixel search
  // HDRES
  #define SSE_LAMBDA_HDRES 1  // Used by mv_cost_err_fn
  #define SAD_LAMBDA_HDRES 8  // Used by mvsad_err_cost during full pixel search
  
  static INLINE const uint8_t *get_buf_from_mv(const struct buf_2d *buf,
                                               const MV *mv) {
    return &buf->buf[mv->row * buf->stride + mv->col];
  }
  
  void av1_set_mv_search_range(MvLimits *mv_limits, const MV *mv) {
    int col_min = (mv->col >> 3) - MAX_FULL_PEL_VAL + (mv->col & 7 ? 1 : 0);
    int row_min = (mv->row >> 3) - MAX_FULL_PEL_VAL + (mv->row & 7 ? 1 : 0);
    int col_max = (mv->col >> 3) + MAX_FULL_PEL_VAL;
    int row_max = (mv->row >> 3) + MAX_FULL_PEL_VAL;
  
    col_min = AOMMAX(col_min, (MV_LOW >> 3) + 1);
    row_min = AOMMAX(row_min, (MV_LOW >> 3) + 1);
    col_max = AOMMIN(col_max, (MV_UPP >> 3) - 1);
    row_max = AOMMIN(row_max, (MV_UPP >> 3) - 1);
  
    // Get intersection of UMV window and valid MV window to reduce # of checks
    // in diamond search.
    if (mv_limits->col_min < col_min) mv_limits->col_min = col_min;
    if (mv_limits->col_max > col_max) mv_limits->col_max = col_max;
    if (mv_limits->row_min < row_min) mv_limits->row_min = row_min;
    if (mv_limits->row_max > row_max) mv_limits->row_max = row_max;
  }
  
  int av1_init_search_range(int size) {
    int sr = 0;
    // Minimum search size no matter what the passed in value.
    size = AOMMAX(16, size);
  
    while ((size << sr) < MAX_FULL_PEL_VAL) sr++;
  
    sr = AOMMIN(sr, MAX_MVSEARCH_STEPS - 2);
    return sr;
  }
  
  // Returns the rate of encoding the current motion vector based on the
  // joint_cost and comp_cost. joint_costs covers the cost of transmitting
  // JOINT_MV, and comp_cost covers the cost of transmitting the actual motion
  // vector.
  static INLINE int mv_cost(const MV *mv, const MV *ref, const int *joint_cost,
                            int *const (*mvcost)[2],
                            MvSubpelPrecision precision) {
    (void)ref;
  #if CONFIG_COMPANDED_MV
    MvSubpelPrecision prec0 =
        AOMMIN(get_companded_mv_precision(mv->row, ref->row), precision);
    MvSubpelPrecision prec1 =
        AOMMIN(get_companded_mv_precision(mv->col, ref->col), precision);
    // If precision is not allowed for the integer mv, return a high barrier
    if (get_mv_component_precision(mv->row) > prec0) return INT_MAX / 2;
    if (get_mv_component_precision(mv->col) > prec1) return INT_MAX / 2;
    return joint_cost[av1_get_mv_joint(mv)] + mvcost[prec0][0][mv->row] +
           mvcost[prec1][1][mv->col];
  #else
    assert(mvcost[precision][0][mv->row] >= 0 &&
           mvcost[precision][0][mv->row] < INT_MAX);
    assert(mvcost[precision][1][mv->col] >= 0 &&
           mvcost[precision][1][mv->col] < INT_MAX);
    return joint_cost[av1_get_mv_joint(mv)] + mvcost[precision][0][mv->row] +
           mvcost[precision][1][mv->col];
  #endif  // CONFIG_COMPANDED_MV
  }
  
  // Returns the cost of encoding the motion vector diff := *mv - *ref. The cost
  // is defined as the rate required to encode diff * weight, rounded to the
  // nearest 2 ** 7.
  // This is NOT used during motion compensation.
  int av1_mv_bit_cost_gen(const MV *mv, const MV *ref,
                          MvSubpelPrecision max_precision, const int *mvjcost,
                          int *const (*mvcost)[2],
  #if CONFIG_FLEX_MVRES
                          int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE],
  #endif  // CONFIG_FLEX_MVRES
                          int weight) {
  #if CONFIG_FLEX_MVRES
    MV ref_ = *ref;
    MvSubpelPrecision precision =
        flex_mv_costs ? get_mv_precision(*mv, max_precision) : max_precision;
    lower_mv_precision(&ref_, precision);
    const MV diff = { mv->row - ref_.row, mv->col - ref_.col };
    int cost = mv_cost(&diff, &ref_, mvjcost, mvcost, precision);
    // The flex mv cost needs to be added only once for compound
    if (flex_mv_costs) {
      assert(max_precision >= MV_SUBPEL_QTR_PRECISION);
  #if DISALLOW_ONE_DOWN_FLEX_MVRES == 2
      assert(IMPLIES(max_precision > precision,
                     ((max_precision - precision) & 1) == 0));
      const int down = (max_precision - precision) >> 1;
  #elif DISALLOW_ONE_DOWN_FLEX_MVRES == 1
      assert(IMPLIES(max_precision > precision, max_precision - precision > 1));
      const int down =
          max_precision > precision ? max_precision - precision - 1 : 0;
  #else
      const int down = max_precision - precision;
  #endif  // DISALLOW_ONE_DOWN_FLEX_MVRES
      cost += flex_mv_costs[max_precision - MV_SUBPEL_QTR_PRECISION][down];
    }
  #else
    const MV diff = { mv->row - ref->row, mv->col - ref->col };
    int cost = mv_cost(&diff, ref, mvjcost, mvcost, max_precision);
  #endif  // CONFIG_FLEX_MVRES
    return (int)ROUND_POWER_OF_TWO_64((int64_t)cost * weight, 7);
  }
  
  int av1_mv_bit_cost_gen2(const MV *mv, const MV *ref,
                           MvSubpelPrecision max_precision, const int *mvjcost,
                           int *const (*mvcost)[2],
  #if CONFIG_FLEX_MVRES
                           int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE],
  #endif  // CONFIG_FLEX_MVRES
                           int weight) {
  #if CONFIG_FLEX_MVRES
    MV ref_[2] = { ref[0], ref[1] };
    const MvSubpelPrecision precision =
        flex_mv_costs ? get_mv_precision2(mv[0], mv[1], max_precision)
                      : max_precision;
    lower_mv_precision(&ref_[0], precision);
    lower_mv_precision(&ref_[1], precision);
    const MV diff[2] = { { mv[0].row - ref_[0].row, mv[0].col - ref_[0].col },
                         { mv[1].row - ref_[1].row, mv[1].col - ref_[1].col } };
    int cost = mv_cost(&diff[0], &ref_[0], mvjcost, mvcost, precision) +
               mv_cost(&diff[1], &ref_[1], mvjcost, mvcost, precision);
    // The flex mv cost needs to be added only once for compound
    if (flex_mv_costs) {
      assert(max_precision >= MV_SUBPEL_QTR_PRECISION);
  #if DISALLOW_ONE_DOWN_FLEX_MVRES == 2
      assert(IMPLIES(max_precision > precision,
                     ((max_precision - precision) & 1) == 0));
      const int down = (max_precision - precision) >> 1;
  #elif DISALLOW_ONE_DOWN_FLEX_MVRES == 1
      assert(IMPLIES(max_precision > precision, max_precision - precision > 1));
      const int down =
          max_precision > precision ? max_precision - precision - 1 : 0;
  #else
      const int down = max_precision - precision;
  #endif  // DISALLOW_ONE_DOWN_FLEX_MVRES
      cost += flex_mv_costs[max_precision - MV_SUBPEL_QTR_PRECISION][down];
    }
  #else
    const MV diff[2] = { { mv[0].row - ref[0].row, mv[0].col - ref[0].col },
                         { mv[1].row - ref[1].row, mv[1].col - ref[1].col } };
    int cost = mv_cost(&diff[0], &ref[0], mvjcost, mvcost, max_precision) +
               mv_cost(&diff[1], &ref[1], mvjcost, mvcost, max_precision);
  #endif  // CONFIG_FLEX_MVRES
    return (int)ROUND_POWER_OF_TWO_64((int64_t)cost * weight, 7);
  }
  
  #define PIXEL_TRANSFORM_ERROR_SCALE 4
  // Returns the cost of using the current mv during the motion search. This is
  // used when var is used as the error metric.
  static int mv_err_cost(const MV *mv, MV ref, MvSubpelPrecision max_precision,
                         MvSubpelPrecision min_precision, const int *mvjcost,
                         int *const (*mvcost)[2],
                         const int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE],
                         int error_per_bit, MV_COST_TYPE mv_cost_type) {
    MvSubpelPrecision pb_precision = max_precision;
    if (flex_mv_costs) {
      pb_precision = AOMMAX(get_mv_precision(*mv, max_precision), min_precision);
    }
    lower_mv_precision(&ref, pb_precision);
    const MV diff = { mv->row - ref.row, mv->col - ref.col };
    const MV abs_diff = { abs(diff.row), abs(diff.col) };
  
    switch (mv_cost_type) {
      case MV_COST_ENTROPY:
        if (mvcost) {
          int cost = mv_cost(&diff, &ref, mvjcost, mvcost, pb_precision);
          if (max_precision >= MV_SUBPEL_QTR_PRECISION && flex_mv_costs) {
  #if DISALLOW_ONE_DOWN_FLEX_MVRES == 2
            assert(IMPLIES(max_precision > pb_precision,
                           ((max_precision - pb_precision) & 1) == 0));
            const int down = (max_precision - pb_precision) >> 1;
  #elif DISALLOW_ONE_DOWN_FLEX_MVRES == 1
            assert(IMPLIES(max_precision > pb_precision,
                           max_precision - pb_precision > 1));
            const int down = max_precision > pb_precision
                                 ? max_precision - pb_precision - 1
                                 : 0;
  #else
            const int down = max_precision - pb_precision;
  #endif  // DISALLOW_ONE_DOWN_FLEX_MVRES
            cost += flex_mv_costs[max_precision - MV_SUBPEL_QTR_PRECISION][down];
          }
  
  #if CONFIG_SKIP_INTERP_FILTER && 0
          // Add penalty for MVs with subpel component.
          // TODO(huisu): currently no gains. Try more experiments.
          unsigned int bias = 0;
          if (mv->row & 7) bias += (1 << AV1_PROB_COST_SHIFT) >> 3;
          if (mv->col & 7) bias += (1 << AV1_PROB_COST_SHIFT) >> 3;
          cost += bias;
  #endif  // CONFIG_SKIP_INTERP_FILTER
  
          return (int)ROUND_POWER_OF_TWO_64((int64_t)cost * error_per_bit,
                                            RDDIV_BITS + AV1_PROB_COST_SHIFT -
                                                RD_EPB_SHIFT +
                                                PIXEL_TRANSFORM_ERROR_SCALE);
        }
        return 0;
      case MV_COST_L1_LOWRES:
        return (SSE_LAMBDA_LOWRES * (abs_diff.row + abs_diff.col)) >> 3;
      case MV_COST_L1_MIDRES:
        return (SSE_LAMBDA_MIDRES * (abs_diff.row + abs_diff.col)) >> 3;
      case MV_COST_L1_HDRES:
        return (SSE_LAMBDA_HDRES * (abs_diff.row + abs_diff.col)) >> 3;
      case MV_COST_NONE: return 0;
      default: assert(0 && "Invalid rd_cost_type"); return 0;
    }
  }
  
  // Returns the cost of using the current mv during the motion search. This is
  // only used during full pixel motion search when sad is used as the error
  // metric.
  static int mvsad_err_cost(const MACROBLOCK *x, const MV *mv, const MV *ref,
                            MvSubpelPrecision precision, int sad_per_bit) {
    const MV diff = { (mv->row - ref->row) * 8, (mv->col - ref->col) * 8 };
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    switch (mv_cost_type) {
      case MV_COST_ENTROPY:
        return ROUND_POWER_OF_TWO((unsigned)mv_cost(&diff, ref, x->nmv_vec_cost,
                                                    x->nmvcost, precision) *
                                      sad_per_bit,
                                  AV1_PROB_COST_SHIFT);
      case MV_COST_L1_LOWRES:
        return (SAD_LAMBDA_LOWRES * (abs(diff.row) + abs(diff.col))) >> 3;
      case MV_COST_L1_MIDRES:
        return (SAD_LAMBDA_MIDRES * (abs(diff.row) + abs(diff.col))) >> 3;
      case MV_COST_L1_HDRES:
        return (SAD_LAMBDA_HDRES * (abs(diff.row) + abs(diff.col))) >> 3;
      case MV_COST_NONE: return 0;
      default: assert(0 && "Invalid rd_cost_type"); return 0;
    }
  }
  
  void av1_init_dsmotion_compensation(search_site_config *cfg, int stride) {
    int len, ss_count = 0;
    int stage_index = MAX_MVSEARCH_STEPS - 1;
  
    cfg->ss[stage_index][0].mv.col = cfg->ss[stage_index][0].mv.row = 0;
    cfg->ss[stage_index][0].offset = 0;
    cfg->stride = stride;
  
    for (len = MAX_FIRST_STEP; len > 0; len /= 2) {
      // Generate offsets for 4 search sites per step.
      const MV ss_mvs[5] = {
        { 0, 0 }, { -len, 0 }, { len, 0 }, { 0, -len }, { 0, len }
      };
      int i;
      for (i = 0; i < 5; ++i) {
        search_site *const ss = &cfg->ss[stage_index][i];
        ss->mv = ss_mvs[i];
        ss->offset = ss->mv.row * stride + ss->mv.col;
      }
      cfg->searches_per_step[stage_index] = 4;
      cfg->radius[stage_index] = len;
      --stage_index;
      ++ss_count;
    }
  
    cfg->ss_count = ss_count;
  }
  
  void av1_init_motion_fpf(search_site_config *cfg, int stride) {
    int ss_count = 0;
    int stage_index = MAX_MVSEARCH_STEPS - 1;
  
    cfg->ss[stage_index][0].mv.col = cfg->ss[stage_index][0].mv.row = 0;
    cfg->ss[stage_index][0].offset = 0;
    cfg->stride = stride;
  
    for (int radius = MAX_FIRST_STEP; radius > 0; radius /= 2) {
      // Generate offsets for 8 search sites per step.
      int tan_radius = AOMMAX((int)(0.41 * radius), 1);
      int num_search_pts = 12;
      if (radius == 1) num_search_pts = 8;
  
      const MV ss_mvs[13] = {
        { 0, 0 },
        { -radius, 0 },
        { radius, 0 },
        { 0, -radius },
        { 0, radius },
        { -radius, -tan_radius },
        { radius, tan_radius },
        { -tan_radius, radius },
        { tan_radius, -radius },
        { -radius, tan_radius },
        { radius, -tan_radius },
        { tan_radius, radius },
        { -tan_radius, -radius },
      };
  
      int i;
      for (i = 0; i <= num_search_pts; ++i) {
        search_site *const ss = &cfg->ss[stage_index][i];
        ss->mv = ss_mvs[i];
        ss->offset = ss->mv.row * stride + ss->mv.col;
      }
      cfg->searches_per_step[stage_index] = num_search_pts;
      cfg->radius[stage_index] = radius;
      --stage_index;
      ++ss_count;
    }
    cfg->ss_count = ss_count;
  }
  
  void av1_init3smotion_compensation(search_site_config *cfg, int stride) {
    int ss_count = 0;
    int stage_index = 0;
    cfg->stride = stride;
    int radius = 1;
    for (stage_index = 0; stage_index < 15; ++stage_index) {
      int tan_radius = AOMMAX((int)(0.41 * radius), 1);
      int num_search_pts = 12;
      if (radius == 1) num_search_pts = 8;
      const MV ss_mvs[13] = {
        { 0, 0 },
        { -radius, 0 },
        { radius, 0 },
        { 0, -radius },
        { 0, radius },
        { -radius, -tan_radius },
        { radius, tan_radius },
        { -tan_radius, radius },
        { tan_radius, -radius },
        { -radius, tan_radius },
        { radius, -tan_radius },
        { tan_radius, radius },
        { -tan_radius, -radius },
      };
  
      for (int i = 0; i <= num_search_pts; ++i) {
        search_site *const ss = &cfg->ss[stage_index][i];
        ss->mv = ss_mvs[i];
        ss->offset = ss->mv.row * stride + ss->mv.col;
      }
      cfg->searches_per_step[stage_index] = num_search_pts;
      cfg->radius[stage_index] = radius;
      ++ss_count;
      radius = (int)AOMMAX((radius * 1.4 + 0.5), radius + 1);
    }
    cfg->ss_count = ss_count;
  }
  
  /*
   * To avoid the penalty for crossing cache-line read, preload the reference
   * area in a small buffer, which is aligned to make sure there won't be crossing
   * cache-line read while reading from this buffer. This reduced the cpu
   * cycles spent on reading ref data in sub-pixel filter functions.
   * TODO: Currently, since sub-pixel search range here is -3 ~ 3, copy 22 rows x
   * 32 cols area that is enough for 16x16 macroblock. Later, for SPLITMV, we
   * could reduce the area.
   */
  
  // convert motion vector component to offset for sv[a]f calc
  static INLINE int sp(int x) { return x & 7; }
  
  static INLINE const uint8_t *pre(const uint8_t *buf, int stride, int r, int c) {
    const int offset = (r >> 3) * stride + (c >> 3);
    return buf + offset;
  }
  
  /* checks if (r, c) has better score than previous best */
  #define CHECK_BETTER(v, r, c)                                             \
    if (c >= minc && c <= maxc && r >= minr && r <= maxr) {                 \
      MV this_mv = { r, c };                                                \
      v = mv_err_cost(&this_mv, *ref_mv, precision, min_precision, mvjcost, \
                      mvcost, flex_mv_costs, error_per_bit, mv_cost_type);  \
      if (second_pred == NULL) {                                            \
        thismse = vfp->svf(pre(y, y_stride, r, c), y_stride, sp(c), sp(r),  \
                           src_address, src_stride, &sse);                  \
      } else if (mask) {                                                    \
        thismse = vfp->msvf(pre(y, y_stride, r, c), y_stride, sp(c), sp(r), \
                            src_address, src_stride, second_pred, mask,     \
                            mask_stride, invert_mask, &sse);                \
      } else {                                                              \
        thismse = vfp->svaf(pre(y, y_stride, r, c), y_stride, sp(c), sp(r), \
                            src_address, src_stride, &sse, second_pred);    \
      }                                                                     \
      v += thismse;                                                         \
      if (v < besterr) {                                                    \
        besterr = v;                                                        \
        br = r;                                                             \
        bc = c;                                                             \
        *distortion = thismse;                                              \
        *sse1 = sse;                                                        \
      }                                                                     \
    } else {                                                                \
      v = INT_MAX;                                                          \
    }
  
  #define CHECK_BETTER0(v, r, c) CHECK_BETTER(v, r, c)
  
  /* checks if (r, c) has better score than previous best */
  #define CHECK_BETTER1(v, r, c)                                             \
    if (c >= minc && c <= maxc && r >= minr && r <= maxr) {                  \
      MV this_mv = { r, c };                                                 \
      thismse = upsampled_pref_error(                                        \
          xd, cm, mi_row, mi_col, &this_mv, vfp, src_address, src_stride,    \
          pre(y, y_stride, r, c), y_stride, sp(c), sp(r), second_pred, mask, \
          mask_stride, invert_mask, w, h, &sse, use_accurate_subpel_search); \
      v = mv_err_cost(&this_mv, *ref_mv, precision, min_precision, mvjcost,  \
                      mvcost, flex_mv_costs, error_per_bit, mv_cost_type);   \
      v += thismse;                                                          \
      if (v < besterr) {                                                     \
        besterr = v;                                                         \
        br = r;                                                              \
        bc = c;                                                              \
        *distortion = thismse;                                               \
        *sse1 = sse;                                                         \
      }                                                                      \
    } else {                                                                 \
      v = INT_MAX;                                                           \
    }
  
  #define FIRST_LEVEL_CHECKS                                       \
    {                                                              \
      unsigned int left, right, up, down, diag;                    \
      CHECK_BETTER(left, tr, tc - hstep);                          \
      CHECK_BETTER(right, tr, tc + hstep);                         \
      CHECK_BETTER(up, tr - hstep, tc);                            \
      CHECK_BETTER(down, tr + hstep, tc);                          \
      whichdir = (left < right ? 0 : 1) + (up < down ? 0 : 2);     \
      switch (whichdir) {                                          \
        case 0: CHECK_BETTER(diag, tr - hstep, tc - hstep); break; \
        case 1: CHECK_BETTER(diag, tr - hstep, tc + hstep); break; \
        case 2: CHECK_BETTER(diag, tr + hstep, tc - hstep); break; \
        case 3: CHECK_BETTER(diag, tr + hstep, tc + hstep); break; \
      }                                                            \
    }
  
  #define SECOND_LEVEL_CHECKS                                       \
    {                                                               \
      int kr, kc;                                                   \
      unsigned int second;                                          \
      if (tr != br && tc != bc) {                                   \
        kr = br - tr;                                               \
        kc = bc - tc;                                               \
        CHECK_BETTER(second, tr + kr, tc + 2 * kc);                 \
        CHECK_BETTER(second, tr + 2 * kr, tc + kc);                 \
      } else if (tr == br && tc != bc) {                            \
        kc = bc - tc;                                               \
        CHECK_BETTER(second, tr + hstep, tc + 2 * kc);              \
        CHECK_BETTER(second, tr - hstep, tc + 2 * kc);              \
        switch (whichdir) {                                         \
          case 0:                                                   \
          case 1: CHECK_BETTER(second, tr + hstep, tc + kc); break; \
          case 2:                                                   \
          case 3: CHECK_BETTER(second, tr - hstep, tc + kc); break; \
        }                                                           \
      } else if (tr != br && tc == bc) {                            \
        kr = br - tr;                                               \
        CHECK_BETTER(second, tr + 2 * kr, tc + hstep);              \
        CHECK_BETTER(second, tr + 2 * kr, tc - hstep);              \
        switch (whichdir) {                                         \
          case 0:                                                   \
          case 2: CHECK_BETTER(second, tr + kr, tc + hstep); break; \
          case 1:                                                   \
          case 3: CHECK_BETTER(second, tr + kr, tc - hstep); break; \
        }                                                           \
      }                                                             \
    }
  
  // TODO(yunqingwang): SECOND_LEVEL_CHECKS_BEST was a rewrote of
  // SECOND_LEVEL_CHECKS, and SECOND_LEVEL_CHECKS should be rewritten
  // later in the same way.
  #define SECOND_LEVEL_CHECKS_BEST(k)                \
    {                                                \
      unsigned int second;                           \
      int br0 = br;                                  \
      int bc0 = bc;                                  \
      assert(tr == br || tc == bc);                  \
      if (tr == br && tc != bc) {                    \
        kc = bc - tc;                                \
      } else if (tr != br && tc == bc) {             \
        kr = br - tr;                                \
      }                                              \
      CHECK_BETTER##k(second, br0 + kr, bc0);        \
      CHECK_BETTER##k(second, br0, bc0 + kc);        \
      if (br0 != br || bc0 != bc) {                  \
        CHECK_BETTER##k(second, br0 + kr, bc0 + kc); \
      }                                              \
    }
  
  #define SETUP_SUBPEL_SEARCH                                             \
    const uint8_t *const src_address = x->plane[0].src.buf;               \
    const int src_stride = x->plane[0].src.stride;                        \
    const MACROBLOCKD *xd = &x->e_mbd;                                    \
    unsigned int besterr = INT_MAX;                                       \
    unsigned int sse;                                                     \
    unsigned int whichdir;                                                \
    int thismse;                                                          \
    MV *bestmv = &x->best_mv.as_mv;                                       \
    const unsigned int halfiters = iters_per_step;                        \
    const unsigned int quarteriters = iters_per_step;                     \
    const unsigned int eighthiters = iters_per_step;                      \
    const int y_stride = xd->plane[0].pre[0].stride;                      \
    const int offset = bestmv->row * y_stride + bestmv->col;              \
    const uint8_t *const y = xd->plane[0].pre[0].buf;                     \
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;                    \
                                                                          \
    int br = bestmv->row * 8;                                             \
    int bc = bestmv->col * 8;                                             \
    int hstep = 4;                                                        \
    int minc, maxc, minr, maxr;                                           \
    int tr = br;                                                          \
    int tc = bc;                                                          \
                                                                          \
    set_subpel_mv_search_range(&x->mv_limits, &minc, &maxc, &minr, &maxr, \
                               ref_mv);                                   \
                                                                          \
    bestmv->row *= 8;                                                     \
    bestmv->col *= 8;
  
  static unsigned int setup_center_error(
      const MACROBLOCKD *xd, const MV *bestmv, const MV *ref_mv,
      int error_per_bit, const aom_variance_fn_ptr_t *vfp,
      const uint8_t *const src, const int src_stride, const uint8_t *const y,
      int y_stride, const uint8_t *second_pred, const uint8_t *mask,
      int mask_stride, int invert_mask, int w, int h, int offset,
      MvSubpelPrecision max_precision, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      unsigned int *sse1, int *distortion, MV_COST_TYPE mv_cost_type) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // CONFIG_FLEX_MVRES
  
    unsigned int besterr;
    if (second_pred != NULL) {
      if (is_cur_buf_hbd(xd)) {
        DECLARE_ALIGNED(16, uint16_t, comp_pred16[MAX_SB_SQUARE]);
        uint8_t *comp_pred = CONVERT_TO_BYTEPTR(comp_pred16);
        if (mask) {
          aom_highbd_comp_mask_pred(comp_pred, second_pred, w, h, y + offset,
                                    y_stride, mask, mask_stride, invert_mask);
        } else {
          aom_highbd_comp_avg_pred(comp_pred, second_pred, w, h, y + offset,
                                   y_stride);
        }
        besterr = vfp->vf(comp_pred, w, src, src_stride, sse1);
      } else {
        DECLARE_ALIGNED(16, uint8_t, comp_pred[MAX_SB_SQUARE]);
        if (mask) {
          aom_comp_mask_pred(comp_pred, second_pred, w, h, y + offset, y_stride,
                             mask, mask_stride, invert_mask);
        } else {
          aom_comp_avg_pred(comp_pred, second_pred, w, h, y + offset, y_stride);
        }
        besterr = vfp->vf(comp_pred, w, src, src_stride, sse1);
      }
    } else {
      besterr = vfp->vf(y + offset, y_stride, src, src_stride, sse1);
    }
    *distortion = besterr;
    besterr += mv_err_cost(bestmv, *ref_mv, max_precision, min_precision, mvjcost,
                           mvcost, flex_mv_costs, error_per_bit, mv_cost_type);
    return besterr;
  }
  
  static INLINE int divide_and_round(int n, int d) {
    return ((n < 0) ^ (d < 0)) ? ((n - d / 2) / d) : ((n + d / 2) / d);
  }
  
  static INLINE int is_cost_list_wellbehaved(int *cost_list) {
    return cost_list[0] < cost_list[1] && cost_list[0] < cost_list[2] &&
           cost_list[0] < cost_list[3] && cost_list[0] < cost_list[4];
  }
  
  // Returns surface minima estimate at given precision in 1/2^n bits.
  // Assume a model for the cost surface: S = A(x - x0)^2 + B(y - y0)^2 + C
  // For a given set of costs S0, S1, S2, S3, S4 at points
  // (y, x) = (0, 0), (0, -1), (1, 0), (0, 1) and (-1, 0) respectively,
  // the solution for the location of the minima (x0, y0) is given by:
  // x0 = 1/2 (S1 - S3)/(S1 + S3 - 2*S0),
  // y0 = 1/2 (S4 - S2)/(S4 + S2 - 2*S0).
  // The code below is an integerized version of that.
  static void get_cost_surf_min(int *cost_list, int *ir, int *ic, int bits) {
    *ic = divide_and_round((cost_list[1] - cost_list[3]) * (1 << (bits - 1)),
                           (cost_list[1] - 2 * cost_list[0] + cost_list[3]));
    *ir = divide_and_round((cost_list[4] - cost_list[2]) * (1 << (bits - 1)),
                           (cost_list[4] - 2 * cost_list[0] + cost_list[2]));
  }
  
  int av1_find_best_sub_pixel_tree_pruned_evenmore(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    SETUP_SUBPEL_SEARCH;
    besterr = setup_center_error(xd, bestmv, ref_mv, error_per_bit, vfp,
                                 src_address, src_stride, y, y_stride,
                                 second_pred, mask, mask_stride, invert_mask, w,
                                 h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
                                 flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
                                 sse1, distortion, mv_cost_type);
    (void)halfiters;
    (void)quarteriters;
    (void)eighthiters;
    (void)whichdir;
    (void)forced_stop;
    (void)hstep;
    (void)use_accurate_subpel_search;
    (void)cm;
    (void)mi_row;
    (void)mi_col;
    (void)do_reset_fractional_mv;
  
    if (cost_list && cost_list[0] != INT_MAX && cost_list[1] != INT_MAX &&
        cost_list[2] != INT_MAX && cost_list[3] != INT_MAX &&
        cost_list[4] != INT_MAX && is_cost_list_wellbehaved(cost_list)) {
      int ir, ic;
      unsigned int minpt;
      get_cost_surf_min(cost_list, &ir, &ic, 2);
      if (ir != 0 || ic != 0) {
        CHECK_BETTER(minpt, tr + 2 * ir, tc + 2 * ic);
      }
    } else {
      FIRST_LEVEL_CHECKS;
      if (halfiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
  
      tr = br;
      tc = bc;
  
      // Each subsequent iteration checks at least one point in common with
      // the last iteration could be 2 ( if diag selected) 1/4 pel
      // Note forced_stop: 0 - full, 1 - qtr only, 2 - half only
      if (precision >= MV_SUBPEL_QTR_PRECISION && forced_stop != 2) {
        hstep >>= 1;
        FIRST_LEVEL_CHECKS;
        if (quarteriters > 1) {
          SECOND_LEVEL_CHECKS;
        }
      }
    }
  
    tr = br;
    tc = bc;
  
    if (precision > MV_SUBPEL_QTR_PRECISION && forced_stop == 0) {
      hstep >>= 1;
      FIRST_LEVEL_CHECKS;
      if (eighthiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
    }
  
    bestmv->row = br;
    bestmv->col = bc;
  
    return besterr;
  }
  
  int av1_find_best_sub_pixel_tree_pruned_more(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // CONFIG_FLEX_MVRES
    SETUP_SUBPEL_SEARCH;
    (void)use_accurate_subpel_search;
    (void)cm;
    (void)mi_row;
    (void)mi_col;
    (void)do_reset_fractional_mv;
  
    besterr = setup_center_error(xd, bestmv, ref_mv, error_per_bit, vfp,
                                 src_address, src_stride, y, y_stride,
                                 second_pred, mask, mask_stride, invert_mask, w,
                                 h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
                                 flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
                                 sse1, distortion, mv_cost_type);
    if (cost_list && cost_list[0] != INT_MAX && cost_list[1] != INT_MAX &&
        cost_list[2] != INT_MAX && cost_list[3] != INT_MAX &&
        cost_list[4] != INT_MAX && is_cost_list_wellbehaved(cost_list)) {
      unsigned int minpt;
      int ir, ic;
      get_cost_surf_min(cost_list, &ir, &ic, 1);
      if (ir != 0 || ic != 0) {
        CHECK_BETTER(minpt, tr + ir * hstep, tc + ic * hstep);
      }
    } else {
      FIRST_LEVEL_CHECKS;
      if (halfiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
    }
  
    // Each subsequent iteration checks at least one point in common with
    // the last iteration could be 2 ( if diag selected) 1/4 pel
    // Note forced_stop: 0 - full, 1 - qtr only, 2 - half only
    if (precision >= MV_SUBPEL_QTR_PRECISION && forced_stop != 2) {
      tr = br;
      tc = bc;
      hstep >>= 1;
      FIRST_LEVEL_CHECKS;
      if (quarteriters > 1) {
        SECOND_LEVEL_CHECKS;
      }
    }
  
    if (precision > MV_SUBPEL_QTR_PRECISION && forced_stop == 0) {
      tr = br;
      tc = bc;
      hstep >>= 1;
      FIRST_LEVEL_CHECKS;
      if (eighthiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
    }
    // These lines insure static analysis doesn't warn that
    // tr and tc aren't used after the above point.
    (void)tr;
    (void)tc;
  
    bestmv->row = br;
    bestmv->col = bc;
  
    return besterr;
  }
  
  int av1_find_best_sub_pixel_tree_pruned(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    SETUP_SUBPEL_SEARCH;
    (void)use_accurate_subpel_search;
    (void)cm;
    (void)mi_row;
    (void)mi_col;
    (void)do_reset_fractional_mv;
  
    besterr = setup_center_error(xd, bestmv, ref_mv, error_per_bit, vfp,
                                 src_address, src_stride, y, y_stride,
                                 second_pred, mask, mask_stride, invert_mask, w,
                                 h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
                                 flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
                                 sse1, distortion, mv_cost_type);
    if (cost_list && cost_list[0] != INT_MAX && cost_list[1] != INT_MAX &&
        cost_list[2] != INT_MAX && cost_list[3] != INT_MAX &&
        cost_list[4] != INT_MAX) {
      unsigned int left, right, up, down, diag;
      whichdir = (cost_list[1] < cost_list[3] ? 0 : 1) +
                 (cost_list[2] < cost_list[4] ? 0 : 2);
      switch (whichdir) {
        case 0:
          CHECK_BETTER(left, tr, tc - hstep);
          CHECK_BETTER(down, tr + hstep, tc);
          CHECK_BETTER(diag, tr + hstep, tc - hstep);
          break;
        case 1:
          CHECK_BETTER(right, tr, tc + hstep);
          CHECK_BETTER(down, tr + hstep, tc);
          CHECK_BETTER(diag, tr + hstep, tc + hstep);
          break;
        case 2:
          CHECK_BETTER(left, tr, tc - hstep);
          CHECK_BETTER(up, tr - hstep, tc);
          CHECK_BETTER(diag, tr - hstep, tc - hstep);
          break;
        case 3:
          CHECK_BETTER(right, tr, tc + hstep);
          CHECK_BETTER(up, tr - hstep, tc);
          CHECK_BETTER(diag, tr - hstep, tc + hstep);
          break;
      }
    } else {
      FIRST_LEVEL_CHECKS;
      if (halfiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
    }
  
    tr = br;
    tc = bc;
  
    // Each subsequent iteration checks at least one point in common with
    // the last iteration could be 2 ( if diag selected) 1/4 pel
    // Note forced_stop: 0 - full, 1 - qtr only, 2 - half only
    if (precision >= MV_SUBPEL_QTR_PRECISION && forced_stop != 2) {
      hstep >>= 1;
      FIRST_LEVEL_CHECKS;
      if (quarteriters > 1) {
        SECOND_LEVEL_CHECKS;
      }
      tr = br;
      tc = bc;
    }
  
    if (precision > MV_SUBPEL_QTR_PRECISION && forced_stop == 0) {
      hstep >>= 1;
      FIRST_LEVEL_CHECKS;
      if (eighthiters > 1) {
        SECOND_LEVEL_CHECKS;
      }
      tr = br;
      tc = bc;
    }
    // These lines insure static analysis doesn't warn that
    // tr and tc aren't used after the above point.
    (void)tr;
    (void)tc;
  
    bestmv->row = br;
    bestmv->col = bc;
  
    return besterr;
  }
  
  /* clang-format off */
  static const MV search_step_table[12] = {
    // left, right, up, down
    { 0, -4 }, { 0, 4 }, { -4, 0 }, { 4, 0 },
    { 0, -2 }, { 0, 2 }, { -2, 0 }, { 2, 0 },
    { 0, -1 }, { 0, 1 }, { -1, 0 }, { 1, 0 }
  };
  /* clang-format on */
  
  static int upsampled_pref_error(MACROBLOCKD *xd, const AV1_COMMON *const cm,
                                  int mi_row, int mi_col, const MV *const mv,
                                  const aom_variance_fn_ptr_t *vfp,
                                  const uint8_t *const src, const int src_stride,
                                  const uint8_t *const y, int y_stride,
                                  int subpel_x_q3, int subpel_y_q3,
                                  const uint8_t *second_pred, const uint8_t *mask,
                                  int mask_stride, int invert_mask, int w, int h,
                                  unsigned int *sse, int subpel_search) {
    unsigned int besterr;
    if (is_cur_buf_hbd(xd)) {
      DECLARE_ALIGNED(16, uint16_t, pred16[MAX_SB_SQUARE]);
      uint8_t *pred8 = CONVERT_TO_BYTEPTR(pred16);
      if (second_pred != NULL) {
        if (mask) {
          aom_highbd_comp_mask_upsampled_pred(
              xd, cm, mi_row, mi_col, mv, pred8, second_pred, w, h, subpel_x_q3,
              subpel_y_q3, y, y_stride, mask, mask_stride, invert_mask, xd->bd,
              subpel_search);
        } else {
          aom_highbd_comp_avg_upsampled_pred(
              xd, cm, mi_row, mi_col, mv, pred8, second_pred, w, h, subpel_x_q3,
              subpel_y_q3, y, y_stride, xd->bd, subpel_search);
        }
      } else {
        aom_highbd_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred8, w, h,
                                  subpel_x_q3, subpel_y_q3, y, y_stride, xd->bd,
                                  subpel_search);
      }
      besterr = vfp->vf(pred8, w, src, src_stride, sse);
    } else {
      DECLARE_ALIGNED(16, uint8_t, pred[MAX_SB_SQUARE]);
      if (second_pred != NULL) {
        if (mask) {
          aom_comp_mask_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred,
                                       second_pred, w, h, subpel_x_q3,
                                       subpel_y_q3, y, y_stride, mask,
                                       mask_stride, invert_mask, subpel_search);
        } else {
          aom_comp_avg_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred,
                                      second_pred, w, h, subpel_x_q3, subpel_y_q3,
                                      y, y_stride, subpel_search);
        }
      } else {
        aom_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred, w, h, subpel_x_q3,
                           subpel_y_q3, y, y_stride, subpel_search);
      }
  
      besterr = vfp->vf(pred, w, src, src_stride, sse);
    }
    return besterr;
  }
  
  static unsigned int upsampled_setup_center_error(
      MACROBLOCKD *xd, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *bestmv, const MV *ref_mv, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, const uint8_t *const src,
      const int src_stride, const uint8_t *const y, int y_stride,
      const uint8_t *second_pred, const uint8_t *mask, int mask_stride,
      int invert_mask, int w, int h, int offset, MvSubpelPrecision max_precision,
      int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      unsigned int *sse1, int *distortion, int subpel_search,
      MV_COST_TYPE mv_cost_type) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    unsigned int besterr =
        upsampled_pref_error(xd, cm, mi_row, mi_col, bestmv, vfp, src, src_stride,
                             y + offset, y_stride, 0, 0, second_pred, mask,
                             mask_stride, invert_mask, w, h, sse1, subpel_search);
    *distortion = besterr;
    besterr += mv_err_cost(bestmv, *ref_mv, max_precision, min_precision, mvjcost,
                           mvcost, flex_mv_costs, error_per_bit, mv_cost_type);
    return besterr;
  }
  
  // when use_accurate_subpel_search == 0
  static INLINE unsigned int estimate_upsampled_pref_error(
      const aom_variance_fn_ptr_t *vfp, const uint8_t *const src,
      const int src_stride, const uint8_t *const pre, int y_stride,
      int subpel_x_q3, int subpel_y_q3, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, unsigned int *sse) {
    if (second_pred == NULL) {
      return vfp->svf(pre, y_stride, subpel_x_q3, subpel_y_q3, src, src_stride,
                      sse);
    } else if (mask) {
      return vfp->msvf(pre, y_stride, subpel_x_q3, subpel_y_q3, src, src_stride,
                       second_pred, mask, mask_stride, invert_mask, sse);
    } else {
      return vfp->svaf(pre, y_stride, subpel_x_q3, subpel_y_q3, src, src_stride,
                       sse, second_pred);
    }
  }
  
  int av1_find_best_sub_pixel_tree(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    const uint8_t *const src_address = x->plane[0].src.buf;
    const int src_stride = x->plane[0].src.stride;
    MACROBLOCKD *xd = &x->e_mbd;
    unsigned int besterr = INT_MAX;
    unsigned int sse;
    unsigned int thismse;
    const int y_stride = xd->plane[0].pre[0].stride;
    MV *bestmv = &x->best_mv.as_mv;
    const int offset = bestmv->row * y_stride + bestmv->col;
    const uint8_t *const y = xd->plane[0].pre[0].buf;
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
  
    int br = bestmv->row * 8;
    int bc = bestmv->col * 8;
    int hstep = 4;
    int iter, round = 3 - forced_stop;
    int tr = br;
    int tc = bc;
    const MV *search_step = search_step_table;
    int idx, best_idx = -1;
    unsigned int cost_array[5];
    int kr, kc;
    int minc, maxc, minr, maxr;
  
    set_subpel_mv_search_range(&x->mv_limits, &minc, &maxc, &minr, &maxr, ref_mv);
  
    round = AOMMIN(round, (int)precision);
  
    bestmv->row *= 8;
    bestmv->col *= 8;
  
    if (use_accurate_subpel_search) {
      besterr = upsampled_setup_center_error(
          xd, cm, mi_row, mi_col, bestmv, ref_mv, error_per_bit, vfp, src_address,
          src_stride, y, y_stride, second_pred, mask, mask_stride, invert_mask, w,
          h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
          flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
          sse1, distortion, use_accurate_subpel_search, mv_cost_type);
    } else {
      besterr = setup_center_error(xd, bestmv, ref_mv, error_per_bit, vfp,
                                   src_address, src_stride, y, y_stride,
                                   second_pred, mask, mask_stride, invert_mask, w,
                                   h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
                                   flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
                                   sse1, distortion, mv_cost_type);
    }
  
    (void)cost_list;  // to silence compiler warning
  
    if (do_reset_fractional_mv) {
      av1_set_fractional_mv(x->fractional_best_mv);
    }
  
    for (iter = 0; iter < round; ++iter) {
      if ((x->fractional_best_mv[iter].as_mv.row == br) &&
          (x->fractional_best_mv[iter].as_mv.col == bc))
        return INT_MAX;
      x->fractional_best_mv[iter].as_mv.row = br;
      x->fractional_best_mv[iter].as_mv.col = bc;
      // Check vertical and horizontal sub-pixel positions.
      for (idx = 0; idx < 4; ++idx) {
        tr = br + search_step[idx].row;
        tc = bc + search_step[idx].col;
        if (tc >= minc && tc <= maxc && tr >= minr && tr <= maxr) {
          MV this_mv = { tr, tc };
  
          if (use_accurate_subpel_search) {
            thismse = upsampled_pref_error(
                xd, cm, mi_row, mi_col, &this_mv, vfp, src_address, src_stride,
                pre(y, y_stride, tr, tc), y_stride, sp(tc), sp(tr), second_pred,
                mask, mask_stride, invert_mask, w, h, &sse,
                use_accurate_subpel_search);
          } else {
            thismse = estimate_upsampled_pref_error(
                vfp, src_address, src_stride, pre(y, y_stride, tr, tc), y_stride,
                sp(tc), sp(tr), second_pred, mask, mask_stride, invert_mask,
                &sse);
          }
  
          cost_array[idx] =
              thismse + mv_err_cost(&this_mv, *ref_mv, precision, min_precision,
                                    mvjcost, mvcost, flex_mv_costs, error_per_bit,
                                    mv_cost_type);
  
          if (cost_array[idx] < besterr) {
            best_idx = idx;
            besterr = cost_array[idx];
            *distortion = thismse;
            *sse1 = sse;
          }
        } else {
          cost_array[idx] = INT_MAX;
        }
      }
  
      // Check diagonal sub-pixel position
      kc = (cost_array[0] <= cost_array[1] ? -hstep : hstep);
      kr = (cost_array[2] <= cost_array[3] ? -hstep : hstep);
  
      tc = bc + kc;
      tr = br + kr;
      if (tc >= minc && tc <= maxc && tr >= minr && tr <= maxr) {
        MV this_mv = { tr, tc };
  
        if (use_accurate_subpel_search) {
          thismse = upsampled_pref_error(
              xd, cm, mi_row, mi_col, &this_mv, vfp, src_address, src_stride,
              pre(y, y_stride, tr, tc), y_stride, sp(tc), sp(tr), second_pred,
              mask, mask_stride, invert_mask, w, h, &sse,
              use_accurate_subpel_search);
        } else {
          thismse = estimate_upsampled_pref_error(
              vfp, src_address, src_stride, pre(y, y_stride, tr, tc), y_stride,
              sp(tc), sp(tr), second_pred, mask, mask_stride, invert_mask, &sse);
        }
  
        cost_array[4] =
            thismse + mv_err_cost(&this_mv, *ref_mv, precision, min_precision,
                                  mvjcost, mvcost, flex_mv_costs, error_per_bit,
                                  mv_cost_type);
  
        if (cost_array[4] < besterr) {
          best_idx = 4;
          besterr = cost_array[4];
          *distortion = thismse;
          *sse1 = sse;
        }
      } else {
        cost_array[idx] = INT_MAX;
      }
  
      if (best_idx < 4 && best_idx >= 0) {
        br += search_step[best_idx].row;
        bc += search_step[best_idx].col;
      } else if (best_idx == 4) {
        br = tr;
        bc = tc;
      }
  
      if (iters_per_step > 1 && best_idx != -1) {
        if (use_accurate_subpel_search) {
          SECOND_LEVEL_CHECKS_BEST(1);
        } else {
          SECOND_LEVEL_CHECKS_BEST(0);
        }
      }
  
      search_step += 4;
      hstep >>= 1;
      best_idx = -1;
    }
  
    // These lines insure static analysis doesn't warn that
    // tr and tc aren't used after the above point.
    (void)tr;
    (void)tc;
  
    bestmv->row = br;
    bestmv->col = bc;
  
    return besterr;
  }
  
  #undef PRE
  #undef CHECK_BETTER
  
  unsigned int av1_compute_motion_cost(const AV1_COMP *cpi, MACROBLOCK *const x,
                                       BLOCK_SIZE bsize, const MV *this_mv) {
    const AV1_COMMON *const cm = &cpi->common;
    MACROBLOCKD *xd = &x->e_mbd;
    const uint8_t *const src = x->plane[0].src.buf;
    const int src_stride = x->plane[0].src.stride;
    uint8_t *const dst = xd->plane[0].dst.buf;
    const int dst_stride = xd->plane[0].dst.stride;
    const aom_variance_fn_ptr_t *vfp = &cpi->fn_ptr[bsize];
    const int_mv ref_mv = av1_get_ref_mv(x, 0);
    unsigned int mse;
    unsigned int sse;
    const int mi_row = xd->mi_row;
    const int mi_col = xd->mi_col;
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MB_MODE_INFO *mbmi = xd->mi[0];
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #endif  // CONFIG_FLEX_MVRES
    MvSubpelPrecision max_precision = mbmi->max_mv_precision;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
  
    av1_enc_build_inter_predictor(cm, xd, mi_row, mi_col, NULL, bsize,
                                  AOM_PLANE_Y, AOM_PLANE_Y);
    mse = vfp->vf(dst, dst_stride, src, src_stride, &sse);
    mse += mv_err_cost(this_mv, ref_mv.as_mv, max_precision, min_precision,
                       x->nmv_vec_cost, x->nmvcost, flex_mv_costs, x->errorperbit,
                       mv_cost_type);
    return mse;
  }
  
  // Refine MV in a small range
  unsigned int av1_refine_warped_mv(const AV1_COMP *cpi, MACROBLOCK *const x,
                                    BLOCK_SIZE bsize, int *pts0, int *pts_inref0,
                                    int total_samples) {
    MACROBLOCKD *xd = &x->e_mbd;
    MB_MODE_INFO *mbmi = xd->mi[0];
    const MV neighbors[16] = { { 0, -1 }, { 1, 0 }, { 0, 1 }, { -1, 0 },
                               { 0, -2 }, { 2, 0 }, { 0, 2 }, { -2, 0 },
                               { 0, -4 }, { 4, 0 }, { 0, 4 }, { -4, 0 },
                               { 0, -8 }, { 8, 0 }, { 0, 8 }, { -8, 0 } };
    const int_mv ref_mv = av1_get_ref_mv(x, 0);
    int16_t br = mbmi->mv[0].as_mv.row;
    int16_t bc = mbmi->mv[0].as_mv.col;
    int16_t *tr = &mbmi->mv[0].as_mv.row;
    int16_t *tc = &mbmi->mv[0].as_mv.col;
    WarpedMotionParams best_wm_params = mbmi->wm_params;
    int best_num_proj_ref = mbmi->num_proj_ref;
    unsigned int bestmse;
    int minc, maxc, minr, maxr;
    const int start = (MV_SUBPEL_EIGHTH_PRECISION - mbmi->max_mv_precision) * 4;
  
    int ite;
  
    set_subpel_mv_search_range(&x->mv_limits, &minc, &maxc, &minr, &maxr,
                               &ref_mv.as_mv);
  
    // Calculate the center position's error
    assert(bc >= minc && bc <= maxc && br >= minr && br <= maxr);
    bestmse = av1_compute_motion_cost(cpi, x, bsize, &mbmi->mv[0].as_mv);
  
    // MV search
    const int mi_row = xd->mi_row;
    const int mi_col = xd->mi_col;
    for (ite = 0; ite < 2; ++ite) {
      int best_idx = -1;
      int idx;
  
      for (idx = start; idx < start + 4; ++idx) {
        unsigned int thismse;
  
        *tr = br + neighbors[idx].row;
        *tc = bc + neighbors[idx].col;
  
        if (*tc >= minc && *tc <= maxc && *tr >= minr && *tr <= maxr) {
          MV this_mv = { *tr, *tc };
          int pts[SAMPLES_ARRAY_SIZE], pts_inref[SAMPLES_ARRAY_SIZE];
  
          memcpy(pts, pts0, total_samples * 2 * sizeof(*pts0));
          memcpy(pts_inref, pts_inref0, total_samples * 2 * sizeof(*pts_inref0));
          if (total_samples > 1)
            mbmi->num_proj_ref =
                av1_selectSamples(&this_mv, pts, pts_inref, total_samples, bsize);
  
          if (!av1_find_projection(mbmi->num_proj_ref, pts, pts_inref, bsize, *tr,
                                   *tc, &mbmi->wm_params, mi_row, mi_col)) {
            thismse = av1_compute_motion_cost(cpi, x, bsize, &this_mv);
  
            if (thismse < bestmse) {
              best_idx = idx;
              best_wm_params = mbmi->wm_params;
              best_num_proj_ref = mbmi->num_proj_ref;
              bestmse = thismse;
            }
          }
        }
      }
  
      if (best_idx == -1) break;
  
      if (best_idx >= 0) {
        br += neighbors[best_idx].row;
        bc += neighbors[best_idx].col;
      }
    }
  
    *tr = br;
    *tc = bc;
    mbmi->wm_params = best_wm_params;
    mbmi->num_proj_ref = best_num_proj_ref;
    return bestmse;
  }
  
  static INLINE int check_bounds(const MvLimits *mv_limits, int row, int col,
                                 int range) {
    return ((row - range) >= mv_limits->row_min) &
           ((row + range) <= mv_limits->row_max) &
           ((col - range) >= mv_limits->col_min) &
           ((col + range) <= mv_limits->col_max);
  }
  
  static INLINE int is_mv_in(const MvLimits *mv_limits, const MV *mv) {
    return (mv->col >= mv_limits->col_min) && (mv->col <= mv_limits->col_max) &&
           (mv->row >= mv_limits->row_min) && (mv->row <= mv_limits->row_max);
  }
  
  #define CHECK_BETTER                                                          \
    {                                                                           \
      if (thissad < bestsad) {                                                  \
        if (use_mvcost)                                                         \
          thissad += mvsad_err_cost(x, &this_mv, &fcenter_mv, max_mv_precision, \
                                    sad_per_bit);                               \
        if (thissad < bestsad) {                                                \
          bestsad = thissad;                                                    \
          best_site = i;                                                        \
        }                                                                       \
      }                                                                         \
    }
  
  #define MAX_PATTERN_SCALES 11
  #define MAX_PATTERN_CANDIDATES 8  // max number of canddiates per scale
  #define PATTERN_CANDIDATES_REF 3  // number of refinement candidates
  
  // Calculate and return a sad+mvcost list around an integer best pel.
  static INLINE void calc_int_cost_list(const AV1_COMMON *cm, const MACROBLOCK *x,
                                        const MV *const ref_mv, int sadpb,
                                        const aom_variance_fn_ptr_t *fn_ptr,
                                        const MV *best_mv, int *cost_list) {
    static const MV neighbors[4] = { { 0, -1 }, { 1, 0 }, { 0, 1 }, { -1, 0 } };
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &x->e_mbd.plane[0].pre[0];
    const MV fcenter_mv = { ref_mv->row >> 3, ref_mv->col >> 3 };
    const int br = best_mv->row;
    const int bc = best_mv->col;
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    unsigned int sse;
    const int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MACROBLOCKD *xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #else
    (void)cm;
  #endif  // CONFIG_FLEX_MVRES
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    cost_list[0] =
        fn_ptr->vf(what->buf, what->stride, get_buf_from_mv(in_what, best_mv),
                   in_what->stride, &sse) +
        mvsad_err_cost(x, best_mv, &fcenter_mv, max_mv_precision, sadpb);
    if (check_bounds(&x->mv_limits, br, bc, 1)) {
      for (int i = 0; i < 4; i++) {
        const MV neighbor_mv = { br + neighbors[i].row, bc + neighbors[i].col };
        const MV neighbor_mv_subpel = { neighbor_mv.row * 8,
                                        neighbor_mv.col * 8 };
        cost_list[i + 1] =
            fn_ptr->vf(what->buf, what->stride,
                       get_buf_from_mv(in_what, &neighbor_mv), in_what->stride,
                       &sse) +
            mv_err_cost(&neighbor_mv_subpel, *ref_mv, max_mv_precision,
                        MV_SUBPEL_NONE, x->nmv_vec_cost, x->nmvcost,
                        flex_mv_costs, x->errorperbit, mv_cost_type);
      }
    } else {
      for (int i = 0; i < 4; i++) {
        const MV neighbor_mv = { br + neighbors[i].row, bc + neighbors[i].col };
        if (!is_mv_in(&x->mv_limits, &neighbor_mv)) {
          cost_list[i + 1] = INT_MAX;
        } else {
          const MV neighbor_mv_subpel = { neighbor_mv.row * 8,
                                          neighbor_mv.col * 8 };
          cost_list[i + 1] =
              fn_ptr->vf(what->buf, what->stride,
                         get_buf_from_mv(in_what, &neighbor_mv), in_what->stride,
                         &sse) +
              mv_err_cost(&neighbor_mv_subpel, *ref_mv, max_mv_precision,
                          MV_SUBPEL_NONE, x->nmv_vec_cost, x->nmvcost,
                          flex_mv_costs, x->errorperbit, mv_cost_type);
        }
      }
    }
  }
  
  static INLINE void calc_int_sad_list(const AV1_COMMON *const cm,
                                       const MACROBLOCK *x,
                                       const MV *const ref_mv, int sadpb,
                                       const aom_variance_fn_ptr_t *fn_ptr,
                                       const MV *best_mv, int *cost_list,
                                       const int use_mvcost, const int bestsad) {
    (void)cm;
    static const MV neighbors[4] = { { 0, -1 }, { 1, 0 }, { 0, 1 }, { -1, 0 } };
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &x->e_mbd.plane[0].pre[0];
    const MV fcenter_mv = { ref_mv->row >> 3, ref_mv->col >> 3 };
    const int br = best_mv->row;
    const int bc = best_mv->col;
    const MACROBLOCKD *xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    if (cost_list[0] == INT_MAX) {
      cost_list[0] = bestsad;
      if (check_bounds(&x->mv_limits, br, bc, 1)) {
        for (int i = 0; i < 4; i++) {
          const MV this_mv = { br + neighbors[i].row, bc + neighbors[i].col };
          cost_list[i + 1] =
              fn_ptr->sdf(what->buf, what->stride,
                          get_buf_from_mv(in_what, &this_mv), in_what->stride);
        }
      } else {
        for (int i = 0; i < 4; i++) {
          const MV this_mv = { br + neighbors[i].row, bc + neighbors[i].col };
          if (!is_mv_in(&x->mv_limits, &this_mv))
            cost_list[i + 1] = INT_MAX;
          else
            cost_list[i + 1] =
                fn_ptr->sdf(what->buf, what->stride,
                            get_buf_from_mv(in_what, &this_mv), in_what->stride);
        }
      }
    } else {
      if (use_mvcost) {
        for (int i = 0; i < 4; i++) {
          const MV this_mv = { br + neighbors[i].row, bc + neighbors[i].col };
          if (cost_list[i + 1] != INT_MAX) {
            cost_list[i + 1] +=
                mvsad_err_cost(x, &this_mv, &fcenter_mv, max_mv_precision, sadpb);
          }
        }
      }
    }
  }
  
  // Generic pattern search function that searches over multiple scales.
  // Each scale can have a different number of candidates and shape of
  // candidates as indicated in the num_candidates and candidates arrays
  // passed into this function
  //
  static int pattern_search(
      const AV1_COMP *cpi, MACROBLOCK *x, MV *start_mv, int search_param,
      int sad_per_bit, int do_init_search, int *cost_list,
      const aom_variance_fn_ptr_t *vfp, int use_mvcost, const MV *center_mv,
      const int num_candidates[MAX_PATTERN_SCALES],
      const MV candidates[MAX_PATTERN_SCALES][MAX_PATTERN_CANDIDATES]) {
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    static const int search_param_to_steps[MAX_MVSEARCH_STEPS] = {
      10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
    };
    int i, s, t;
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    const int last_is_4 = num_candidates[0] == 4;
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
    int br, bc;
    int bestsad = INT_MAX;
    int thissad;
    int k = -1;
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    assert(search_param < MAX_MVSEARCH_STEPS);
    int best_init_s = search_param_to_steps[search_param];
    // adjust ref_mv to make sure it is within MV range
    clamp_mv(start_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    br = start_mv->row;
    bc = start_mv->col;
    if (cost_list != NULL) {
      cost_list[0] = cost_list[1] = cost_list[2] = cost_list[3] = cost_list[4] =
          INT_MAX;
    }
  
    // Work out the start point for the search
    bestsad =
        vfp->sdf(what->buf, what->stride, get_buf_from_mv(in_what, start_mv),
                 in_what->stride) +
        mvsad_err_cost(x, start_mv, &fcenter_mv, max_mv_precision, sad_per_bit);
  
    // Search all possible scales upto the search param around the center point
    // pick the scale of the point that is best as the starting scale of
    // further steps around it.
    if (do_init_search) {
      s = best_init_s;
      best_init_s = -1;
      for (t = 0; t <= s; ++t) {
        int best_site = -1;
        if (check_bounds(&x->mv_limits, br, bc, 1 << t)) {
          for (i = 0; i < num_candidates[t]; i++) {
            const MV this_mv = { br + candidates[t][i].row,
                                 bc + candidates[t][i].col };
            thissad =
                vfp->sdf(what->buf, what->stride,
                         get_buf_from_mv(in_what, &this_mv), in_what->stride);
            CHECK_BETTER
          }
        } else {
          for (i = 0; i < num_candidates[t]; i++) {
            const MV this_mv = { br + candidates[t][i].row,
                                 bc + candidates[t][i].col };
            if (!is_mv_in(&x->mv_limits, &this_mv)) continue;
            thissad =
                vfp->sdf(what->buf, what->stride,
                         get_buf_from_mv(in_what, &this_mv), in_what->stride);
            CHECK_BETTER
          }
        }
        if (best_site == -1) {
          continue;
        } else {
          best_init_s = t;
          k = best_site;
        }
      }
      if (best_init_s != -1) {
        br += candidates[best_init_s][k].row;
        bc += candidates[best_init_s][k].col;
      }
    }
  
    // If the center point is still the best, just skip this and move to
    // the refinement step.
    if (best_init_s != -1) {
      const int last_s = (last_is_4 && cost_list != NULL);
      int best_site = -1;
      s = best_init_s;
  
      for (; s >= last_s; s--) {
        // No need to search all points the 1st time if initial search was used
        if (!do_init_search || s != best_init_s) {
          if (check_bounds(&x->mv_limits, br, bc, 1 << s)) {
            for (i = 0; i < num_candidates[s]; i++) {
              const MV this_mv = { br + candidates[s][i].row,
                                   bc + candidates[s][i].col };
              thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          } else {
            for (i = 0; i < num_candidates[s]; i++) {
              const MV this_mv = { br + candidates[s][i].row,
                                   bc + candidates[s][i].col };
              if (!is_mv_in(&x->mv_limits, &this_mv)) continue;
              thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          }
  
          if (best_site == -1) {
            continue;
          } else {
            br += candidates[s][best_site].row;
            bc += candidates[s][best_site].col;
            k = best_site;
          }
        }
  
        do {
          int next_chkpts_indices[PATTERN_CANDIDATES_REF];
          best_site = -1;
          next_chkpts_indices[0] = (k == 0) ? num_candidates[s] - 1 : k - 1;
          next_chkpts_indices[1] = k;
          next_chkpts_indices[2] = (k == num_candidates[s] - 1) ? 0 : k + 1;
  
          if (check_bounds(&x->mv_limits, br, bc, 1 << s)) {
            for (i = 0; i < PATTERN_CANDIDATES_REF; i++) {
              const MV this_mv = {
                br + candidates[s][next_chkpts_indices[i]].row,
                bc + candidates[s][next_chkpts_indices[i]].col
              };
              thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          } else {
            for (i = 0; i < PATTERN_CANDIDATES_REF; i++) {
              const MV this_mv = {
                br + candidates[s][next_chkpts_indices[i]].row,
                bc + candidates[s][next_chkpts_indices[i]].col
              };
              if (!is_mv_in(&x->mv_limits, &this_mv)) continue;
              thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          }
  
          if (best_site != -1) {
            k = next_chkpts_indices[best_site];
            br += candidates[s][k].row;
            bc += candidates[s][k].col;
          }
        } while (best_site != -1);
      }
  
      // Note: If we enter the if below, then cost_list must be non-NULL.
      if (s == 0) {
        cost_list[0] = bestsad;
        if (!do_init_search || s != best_init_s) {
          if (check_bounds(&x->mv_limits, br, bc, 1 << s)) {
            for (i = 0; i < num_candidates[s]; i++) {
              const MV this_mv = { br + candidates[s][i].row,
                                   bc + candidates[s][i].col };
              cost_list[i + 1] = thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          } else {
            for (i = 0; i < num_candidates[s]; i++) {
              const MV this_mv = { br + candidates[s][i].row,
                                   bc + candidates[s][i].col };
              if (!is_mv_in(&x->mv_limits, &this_mv)) continue;
              cost_list[i + 1] = thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          }
  
          if (best_site != -1) {
            br += candidates[s][best_site].row;
            bc += candidates[s][best_site].col;
            k = best_site;
          }
        }
        while (best_site != -1) {
          int next_chkpts_indices[PATTERN_CANDIDATES_REF];
          best_site = -1;
          next_chkpts_indices[0] = (k == 0) ? num_candidates[s] - 1 : k - 1;
          next_chkpts_indices[1] = k;
          next_chkpts_indices[2] = (k == num_candidates[s] - 1) ? 0 : k + 1;
          cost_list[1] = cost_list[2] = cost_list[3] = cost_list[4] = INT_MAX;
          cost_list[((k + 2) % 4) + 1] = cost_list[0];
          cost_list[0] = bestsad;
  
          if (check_bounds(&x->mv_limits, br, bc, 1 << s)) {
            for (i = 0; i < PATTERN_CANDIDATES_REF; i++) {
              const MV this_mv = {
                br + candidates[s][next_chkpts_indices[i]].row,
                bc + candidates[s][next_chkpts_indices[i]].col
              };
              cost_list[next_chkpts_indices[i] + 1] = thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          } else {
            for (i = 0; i < PATTERN_CANDIDATES_REF; i++) {
              const MV this_mv = {
                br + candidates[s][next_chkpts_indices[i]].row,
                bc + candidates[s][next_chkpts_indices[i]].col
              };
              if (!is_mv_in(&x->mv_limits, &this_mv)) {
                cost_list[next_chkpts_indices[i] + 1] = INT_MAX;
                continue;
              }
              cost_list[next_chkpts_indices[i] + 1] = thissad =
                  vfp->sdf(what->buf, what->stride,
                           get_buf_from_mv(in_what, &this_mv), in_what->stride);
              CHECK_BETTER
            }
          }
  
          if (best_site != -1) {
            k = next_chkpts_indices[best_site];
            br += candidates[s][k].row;
            bc += candidates[s][k].col;
          }
        }
      }
    }
  
    // Returns the one-away integer pel cost/sad around the best as follows:
    // cost_list[0]: cost/sad at the best integer pel
    // cost_list[1]: cost/sad at delta {0, -1} (left)   from the best integer
    // pel cost_list[2]: cost/sad at delta { 1, 0} (bottom) from the best
    // integer pel cost_list[3]: cost/sad at delta { 0, 1} (right)  from the
    // best integer pel cost_list[4]: cost/sad at delta {-1, 0} (top)    from
    // the best integer pel
    if (cost_list) {
      const MV best_int_mv = { br, bc };
      if (last_is_4) {
        calc_int_sad_list(&cpi->common, x, center_mv, sad_per_bit, vfp,
                          &best_int_mv, cost_list, use_mvcost, bestsad);
      } else {
        calc_int_cost_list(&cpi->common, x, center_mv, sad_per_bit, vfp,
                           &best_int_mv, cost_list);
      }
    }
    x->best_mv.as_mv.row = br;
    x->best_mv.as_mv.col = bc;
    return bestsad;
  }
  
  int av1_get_mvpred_var(const AV1_COMMON *cm, const MACROBLOCK *x,
                         const MV *best_mv, const MV *center_mv,
                         const aom_variance_fn_ptr_t *vfp, int use_var) {
    const MACROBLOCKD *const xd = &x->e_mbd;
  #if CONFIG_EXT_IBC_MODES
    const uint8_t *what_buf = CONVERT_TO_BYTEPTR(x->ibc_src);
    const int what_stride = 128;
  #else
    const struct buf_2d *const what = &x->plane[0].src;
    const uint8_t *what_buf = what->buf;
    const int what_stride = what->stride;
  #endif  // CONFIG_EXT_IBC_MODES
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    const MV mv = { best_mv->row * 8, best_mv->col * 8 };
    unsigned int sse, var;
    const int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #else
    (void)cm;
  #endif  // CONFIG_FLEX_MVRES
  
    var = vfp->vf(what_buf, what_stride, get_buf_from_mv(in_what, best_mv),
                  in_what->stride, &sse);
  
    if (!use_var) var = sse;
  
    return var + mv_err_cost(&mv, *center_mv, max_mv_precision, MV_SUBPEL_NONE,
                             x->nmv_vec_cost, x->nmvcost, flex_mv_costs,
                             x->errorperbit, mv_cost_type);
  }
  
  int av1_get_mvpred_av_var(const AV1_COMMON *cm, const MACROBLOCK *x,
                            const MV *best_mv, const MV *center_mv,
                            const uint8_t *second_pred,
                            const aom_variance_fn_ptr_t *vfp, int use_mvcost) {
    const MACROBLOCKD *const xd = &x->e_mbd;
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    const MV mv = { best_mv->row * 8, best_mv->col * 8 };
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    unsigned int unused;
    const int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #else
    (void)cm;
  #endif  // CONFIG_FLEX_MVRES
  
    return vfp->svaf(get_buf_from_mv(in_what, best_mv), in_what->stride, 0, 0,
                     what->buf, what->stride, &unused, second_pred) +
           (use_mvcost ? mv_err_cost(&mv, *center_mv, max_mv_precision,
                                     MV_SUBPEL_NONE, x->nmv_vec_cost, x->nmvcost,
                                     flex_mv_costs, x->errorperbit, mv_cost_type)
                       : 0);
  }
  
  int av1_get_mvpred_mask_var(const AV1_COMMON *cm, const MACROBLOCK *x,
                              const MV *best_mv, const MV *center_mv,
                              const uint8_t *second_pred, const uint8_t *mask,
                              int mask_stride, int invert_mask,
                              const aom_variance_fn_ptr_t *vfp, int use_mvcost) {
    const MACROBLOCKD *const xd = &x->e_mbd;
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    const MV mv = { best_mv->row * 8, best_mv->col * 8 };
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    unsigned int unused;
    const int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #else
    (void)cm;
  #endif  // CONFIG_FLEX_MVRES
  
    return vfp->msvf(what->buf, what->stride, 0, 0,
                     get_buf_from_mv(in_what, best_mv), in_what->stride,
                     second_pred, mask, mask_stride, invert_mask, &unused) +
           (use_mvcost ? mv_err_cost(&mv, *center_mv, max_mv_precision,
                                     MV_SUBPEL_NONE, x->nmv_vec_cost, x->nmvcost,
                                     flex_mv_costs, x->errorperbit, mv_cost_type)
                       : 0);
  }
  
  int av1_hex_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *start_mv,
                     int search_param, int sad_per_bit, int do_init_search,
                     int *cost_list, const aom_variance_fn_ptr_t *vfp,
                     int use_mvcost, const MV *center_mv) {
    // First scale has 8-closest points, the rest have 6 points in hex shape
    // at increasing scales
    static const int hex_num_candidates[MAX_PATTERN_SCALES] = { 8, 6, 6, 6, 6, 6,
                                                                6, 6, 6, 6, 6 };
    // Note that the largest candidate step at each scale is 2^scale
    /* clang-format off */
    static const MV hex_candidates[MAX_PATTERN_SCALES][MAX_PATTERN_CANDIDATES] = {
      { { -1, -1 }, { 0, -1 }, { 1, -1 }, { 1, 0 }, { 1, 1 }, { 0, 1 }, { -1, 1 },
        { -1, 0 } },
      { { -1, -2 }, { 1, -2 }, { 2, 0 }, { 1, 2 }, { -1, 2 }, { -2, 0 } },
      { { -2, -4 }, { 2, -4 }, { 4, 0 }, { 2, 4 }, { -2, 4 }, { -4, 0 } },
      { { -4, -8 }, { 4, -8 }, { 8, 0 }, { 4, 8 }, { -4, 8 }, { -8, 0 } },
      { { -8, -16 }, { 8, -16 }, { 16, 0 }, { 8, 16 }, { -8, 16 }, { -16, 0 } },
      { { -16, -32 }, { 16, -32 }, { 32, 0 }, { 16, 32 }, { -16, 32 },
        { -32, 0 } },
      { { -32, -64 }, { 32, -64 }, { 64, 0 }, { 32, 64 }, { -32, 64 },
        { -64, 0 } },
      { { -64, -128 }, { 64, -128 }, { 128, 0 }, { 64, 128 }, { -64, 128 },
        { -128, 0 } },
      { { -128, -256 }, { 128, -256 }, { 256, 0 }, { 128, 256 }, { -128, 256 },
        { -256, 0 } },
      { { -256, -512 }, { 256, -512 }, { 512, 0 }, { 256, 512 }, { -256, 512 },
        { -512, 0 } },
      { { -512, -1024 }, { 512, -1024 }, { 1024, 0 }, { 512, 1024 },
        { -512, 1024 }, { -1024, 0 } },
    };
    /* clang-format on */
    return pattern_search(cpi, x, start_mv, search_param, sad_per_bit,
                          do_init_search, cost_list, vfp, use_mvcost, center_mv,
                          hex_num_candidates, hex_candidates);
  }
  
  static int bigdia_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *start_mv,
                           int search_param, int sad_per_bit, int do_init_search,
                           int *cost_list, const aom_variance_fn_ptr_t *vfp,
                           int use_mvcost, const MV *center_mv) {
    // First scale has 4-closest points, the rest have 8 points in diamond
    // shape at increasing scales
    static const int bigdia_num_candidates[MAX_PATTERN_SCALES] = {
      4, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    };
    // Note that the largest candidate step at each scale is 2^scale
    /* clang-format off */
    static const MV
        bigdia_candidates[MAX_PATTERN_SCALES][MAX_PATTERN_CANDIDATES] = {
          { { 0, -1 }, { 1, 0 }, { 0, 1 }, { -1, 0 } },
          { { -1, -1 }, { 0, -2 }, { 1, -1 }, { 2, 0 }, { 1, 1 }, { 0, 2 },
            { -1, 1 }, { -2, 0 } },
          { { -2, -2 }, { 0, -4 }, { 2, -2 }, { 4, 0 }, { 2, 2 }, { 0, 4 },
            { -2, 2 }, { -4, 0 } },
          { { -4, -4 }, { 0, -8 }, { 4, -4 }, { 8, 0 }, { 4, 4 }, { 0, 8 },
            { -4, 4 }, { -8, 0 } },
          { { -8, -8 }, { 0, -16 }, { 8, -8 }, { 16, 0 }, { 8, 8 }, { 0, 16 },
            { -8, 8 }, { -16, 0 } },
          { { -16, -16 }, { 0, -32 }, { 16, -16 }, { 32, 0 }, { 16, 16 },
            { 0, 32 }, { -16, 16 }, { -32, 0 } },
          { { -32, -32 }, { 0, -64 }, { 32, -32 }, { 64, 0 }, { 32, 32 },
            { 0, 64 }, { -32, 32 }, { -64, 0 } },
          { { -64, -64 }, { 0, -128 }, { 64, -64 }, { 128, 0 }, { 64, 64 },
            { 0, 128 }, { -64, 64 }, { -128, 0 } },
          { { -128, -128 }, { 0, -256 }, { 128, -128 }, { 256, 0 }, { 128, 128 },
            { 0, 256 }, { -128, 128 }, { -256, 0 } },
          { { -256, -256 }, { 0, -512 }, { 256, -256 }, { 512, 0 }, { 256, 256 },
            { 0, 512 }, { -256, 256 }, { -512, 0 } },
          { { -512, -512 }, { 0, -1024 }, { 512, -512 }, { 1024, 0 },
            { 512, 512 }, { 0, 1024 }, { -512, 512 }, { -1024, 0 } },
        };
    /* clang-format on */
    return pattern_search(cpi, x, start_mv, search_param, sad_per_bit,
                          do_init_search, cost_list, vfp, use_mvcost, center_mv,
                          bigdia_num_candidates, bigdia_candidates);
  }
  
  static int square_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *start_mv,
                           int search_param, int sad_per_bit, int do_init_search,
                           int *cost_list, const aom_variance_fn_ptr_t *vfp,
                           int use_mvcost, const MV *center_mv) {
    // All scales have 8 closest points in square shape
    static const int square_num_candidates[MAX_PATTERN_SCALES] = {
      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    };
    // Note that the largest candidate step at each scale is 2^scale
    /* clang-format off */
    static const MV
        square_candidates[MAX_PATTERN_SCALES][MAX_PATTERN_CANDIDATES] = {
          { { -1, -1 }, { 0, -1 }, { 1, -1 }, { 1, 0 }, { 1, 1 }, { 0, 1 },
            { -1, 1 }, { -1, 0 } },
          { { -2, -2 }, { 0, -2 }, { 2, -2 }, { 2, 0 }, { 2, 2 }, { 0, 2 },
            { -2, 2 }, { -2, 0 } },
          { { -4, -4 }, { 0, -4 }, { 4, -4 }, { 4, 0 }, { 4, 4 }, { 0, 4 },
            { -4, 4 }, { -4, 0 } },
          { { -8, -8 }, { 0, -8 }, { 8, -8 }, { 8, 0 }, { 8, 8 }, { 0, 8 },
            { -8, 8 }, { -8, 0 } },
          { { -16, -16 }, { 0, -16 }, { 16, -16 }, { 16, 0 }, { 16, 16 },
            { 0, 16 }, { -16, 16 }, { -16, 0 } },
          { { -32, -32 }, { 0, -32 }, { 32, -32 }, { 32, 0 }, { 32, 32 },
            { 0, 32 }, { -32, 32 }, { -32, 0 } },
          { { -64, -64 }, { 0, -64 }, { 64, -64 }, { 64, 0 }, { 64, 64 },
            { 0, 64 }, { -64, 64 }, { -64, 0 } },
          { { -128, -128 }, { 0, -128 }, { 128, -128 }, { 128, 0 }, { 128, 128 },
            { 0, 128 }, { -128, 128 }, { -128, 0 } },
          { { -256, -256 }, { 0, -256 }, { 256, -256 }, { 256, 0 }, { 256, 256 },
            { 0, 256 }, { -256, 256 }, { -256, 0 } },
          { { -512, -512 }, { 0, -512 }, { 512, -512 }, { 512, 0 }, { 512, 512 },
            { 0, 512 }, { -512, 512 }, { -512, 0 } },
          { { -1024, -1024 }, { 0, -1024 }, { 1024, -1024 }, { 1024, 0 },
            { 1024, 1024 }, { 0, 1024 }, { -1024, 1024 }, { -1024, 0 } },
        };
    /* clang-format on */
    return pattern_search(cpi, x, start_mv, search_param, sad_per_bit,
                          do_init_search, cost_list, vfp, use_mvcost, center_mv,
                          square_num_candidates, square_candidates);
  }
  
  static int fast_hex_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *ref_mv,
                             int search_param, int sad_per_bit,
                             int do_init_search,  // must be zero for fast_hex
                             int *cost_list, const aom_variance_fn_ptr_t *vfp,
                             int use_mvcost, const MV *center_mv) {
    return av1_hex_search(
        cpi, x, ref_mv, AOMMAX(MAX_MVSEARCH_STEPS - 2, search_param), sad_per_bit,
        do_init_search, cost_list, vfp, use_mvcost, center_mv);
  }
  
  static int fast_dia_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *ref_mv,
                             int search_param, int sad_per_bit,
                             int do_init_search, int *cost_list,
                             const aom_variance_fn_ptr_t *vfp, int use_mvcost,
                             const MV *center_mv) {
    return bigdia_search(
        cpi, x, ref_mv, AOMMAX(MAX_MVSEARCH_STEPS - 2, search_param), sad_per_bit,
        do_init_search, cost_list, vfp, use_mvcost, center_mv);
  }
  
  #undef CHECK_BETTER
  
  // Exhuastive motion search around a given centre position with a given
  // step size.
  static int exhuastive_mesh_search(const AV1_COMMON *cm, MACROBLOCK *x,
                                    MV *ref_mv, MV *best_mv, int range, int step,
                                    int sad_per_bit,
                                    const aom_variance_fn_ptr_t *fn_ptr,
                                    const MV *center_mv) {
    (void)cm;
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
  #if CONFIG_EXT_IBC_MODES
    const uint8_t *what_buf = CONVERT_TO_BYTEPTR(x->ibc_src);
    const int what_stride = 128;  // Fixed stride (128x128 Scratch Buffer)
  #else
    const struct buf_2d *const what = &x->plane[0].src;
    const uint8_t *what_buf = what->buf;
    const int what_stride = what->stride;
  #endif  // CONFIG_EXT_IBC_MODES
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    MV fcenter_mv = { center_mv->row, center_mv->col };
    unsigned int best_sad = INT_MAX;
    int r, c, i;
    int start_col, end_col, start_row, end_row;
    int col_step = (step > 1) ? step : 4;
  
    assert(step >= 1);
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    clamp_mv(&fcenter_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    *best_mv = fcenter_mv;
  
    best_sad =
        fn_ptr->sdf(what_buf, what_stride, get_buf_from_mv(in_what, &fcenter_mv),
                    in_what->stride) +
        mvsad_err_cost(x, &fcenter_mv, ref_mv, max_mv_precision, sad_per_bit);
    start_row = AOMMAX(-range, x->mv_limits.row_min - fcenter_mv.row);
    start_col = AOMMAX(-range, x->mv_limits.col_min - fcenter_mv.col);
    end_row = AOMMIN(range, x->mv_limits.row_max - fcenter_mv.row);
    end_col = AOMMIN(range, x->mv_limits.col_max - fcenter_mv.col);
  
    for (r = start_row; r <= end_row; r += step) {
      for (c = start_col; c <= end_col; c += col_step) {
        // Step > 1 means we are not checking every location in this pass.
        if (step > 1) {
          const MV mv = { fcenter_mv.row + r, fcenter_mv.col + c };
          unsigned int sad =
              fn_ptr->sdf(what_buf, what_stride, get_buf_from_mv(in_what, &mv),
                          in_what->stride);
          if (sad < best_sad) {
            sad += mvsad_err_cost(x, &mv, ref_mv, max_mv_precision, sad_per_bit);
            if (sad < best_sad) {
              best_sad = sad;
              x->second_best_mv.as_mv = *best_mv;
              *best_mv = mv;
            }
          }
        } else {
          // 4 sads in a single call if we are checking every location
          if (c + 3 <= end_col) {
            unsigned int sads[4];
            const uint8_t *addrs[4];
            for (i = 0; i < 4; ++i) {
              const MV mv = { fcenter_mv.row + r, fcenter_mv.col + c + i };
              addrs[i] = get_buf_from_mv(in_what, &mv);
            }
            fn_ptr->sdx4df(what_buf, what_stride, addrs, in_what->stride, sads);
  
            for (i = 0; i < 4; ++i) {
              if (sads[i] < best_sad) {
                const MV mv = { fcenter_mv.row + r, fcenter_mv.col + c + i };
                const unsigned int sad =
                    sads[i] +
                    mvsad_err_cost(x, &mv, ref_mv, max_mv_precision, sad_per_bit);
                if (sad < best_sad) {
                  best_sad = sad;
                  x->second_best_mv.as_mv = *best_mv;
                  *best_mv = mv;
                }
              }
            }
          } else {
            for (i = 0; i < end_col - c; ++i) {
              const MV mv = { fcenter_mv.row + r, fcenter_mv.col + c + i };
              unsigned int sad =
                  fn_ptr->sdf(what_buf, what_stride,
                              get_buf_from_mv(in_what, &mv), in_what->stride);
              if (sad < best_sad) {
                sad +=
                    mvsad_err_cost(x, &mv, ref_mv, max_mv_precision, sad_per_bit);
                if (sad < best_sad) {
                  best_sad = sad;
                  x->second_best_mv.as_mv = *best_mv;
                  *best_mv = mv;
                }
              }
            }
          }
        }
      }
    }
  
    return best_sad;
  }
  
  int av1_diamond_search_sad_c(const AV1_COMMON *const cm, MACROBLOCK *x,
                               const search_site_config *cfg, MV *ref_mv,
                               MV *best_mv, int search_param, int sad_per_bit,
                               int *num00, const aom_variance_fn_ptr_t *fn_ptr,
                               const MV *center_mv) {
    (void)cm;
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
  #if CONFIG_EXT_IBC_MODES
    uint8_t *what = CONVERT_TO_BYTEPTR(x->ibc_src);
    const int what_stride = 128;  // Fixed stride (128x128 Scratch Buffer)
  #else
    uint8_t *what = x->plane[0].src.buf;
    const int what_stride = x->plane[0].src.stride;
  #endif  // CONFIG_EXT_IBC_MODES
    const uint8_t *in_what;
    const int in_what_stride = xd->plane[0].pre[0].stride;
    const uint8_t *best_address;
  
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    unsigned int bestsad = INT_MAX;
    int best_site = 0;
    int is_off_center = 0;
  
    int ref_row;
    int ref_col;
  
    // search_param determines the length of the initial step and hence the number
    // of iterations.
    const int tot_steps = cfg->ss_count - 1 - search_param;
  
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    clamp_mv(ref_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    ref_row = ref_mv->row;
    ref_col = ref_mv->col;
    *num00 = 0;
    best_mv->row = ref_row;
    best_mv->col = ref_col;
  
    // Work out the start point for the search
    in_what = xd->plane[0].pre[0].buf + ref_row * in_what_stride + ref_col;
    best_address = in_what;
  
    // Check the starting position
    bestsad =
        fn_ptr->sdf(what, what_stride, in_what, in_what_stride) +
        mvsad_err_cost(x, best_mv, &fcenter_mv, max_mv_precision, sad_per_bit);
  
    for (int step = tot_steps; step >= 0; --step) {
      const search_site *ss = cfg->ss[step];
      best_site = 0;
      // TODO(jingning): Bring back sdx4df optimization for speed later.
      for (int idx = 1; idx <= cfg->searches_per_step[step]; ++idx) {
        // Trap illegal vectors
        const MV this_mv = { best_mv->row + ss[idx].mv.row,
                             best_mv->col + ss[idx].mv.col };
  
        if (is_mv_in(&x->mv_limits, &this_mv)) {
          const uint8_t *const check_here = ss[idx].offset + best_address;
          unsigned int thissad =
              fn_ptr->sdf(what, what_stride, check_here, in_what_stride);
  
          if (thissad < bestsad) {
            thissad += mvsad_err_cost(x, &this_mv, &fcenter_mv,
                                      mbmi->max_mv_precision, sad_per_bit);
            if (thissad < bestsad) {
              bestsad = thissad;
              best_site = idx;
            }
          }
        }
      }
  
      if (best_site != 0) {
        x->second_best_mv.as_mv = *best_mv;
        best_mv->row += ss[best_site].mv.row;
        best_mv->col += ss[best_site].mv.col;
        best_address += ss[best_site].offset;
        is_off_center = 1;
      }
  
      if (is_off_center == 0) (*num00)++;
    }
  
    return bestsad;
  }
  
  /* do_refine: If last step (1-away) of n-step search doesn't pick the center
                point as the best match, we will do a final 1-away diamond
                refining search  */
  static int full_pixel_diamond(const AV1_COMP *const cpi, MACROBLOCK *x,
                                MV *mvp_full, int step_param, int use_var,
                                int sadpb, int further_steps, int *cost_list,
                                const aom_variance_fn_ptr_t *fn_ptr,
                                const MV *ref_mv, const search_site_config *cfg) {
    MV temp_mv;
    int thissme, n, num00 = 0;
    int bestsme =
        cpi->diamond_search_sad(&cpi->common, x, cfg, mvp_full, &temp_mv,
                                step_param, sadpb, &n, fn_ptr, ref_mv);
    if (bestsme < INT_MAX)
      bestsme =
          av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr, use_var);
  
    x->best_mv.as_mv = temp_mv;
  
    // If there won't be more n-step search, check to see if refining search is
    // needed.
    while (n < further_steps) {
      ++n;
  
      if (num00) {
        num00--;
      } else {
        thissme = cpi->diamond_search_sad(&cpi->common, x, cfg, mvp_full,
                                          &temp_mv, step_param + n, sadpb, &num00,
                                          fn_ptr, ref_mv);
        if (thissme < INT_MAX)
          thissme = av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr,
                                       use_var);
  
        if (thissme < bestsme) {
          bestsme = thissme;
          x->best_mv.as_mv = temp_mv;
        }
      }
    }
  
    // Return cost list.
    if (cost_list) {
      calc_int_cost_list(&cpi->common, x, ref_mv, sadpb, fn_ptr,
                         &x->best_mv.as_mv, cost_list);
    }
    return bestsme;
  }
  
  #define MIN_RANGE 7
  #define MAX_RANGE 256
  #define MIN_INTERVAL 1
  // Runs an limited range exhaustive mesh search using a pattern set
  // according to the encode speed profile.
  static int full_pixel_exhaustive(const AV1_COMP *const cpi, MACROBLOCK *x,
                                   const MV *centre_mv_full, int sadpb,
                                   int *cost_list,
                                   const aom_variance_fn_ptr_t *fn_ptr,
                                   const MV *ref_mv, MV *dst_mv) {
    const SPEED_FEATURES *const sf = &cpi->sf;
    MV temp_mv = { centre_mv_full->row, centre_mv_full->col };
    MV f_ref_mv = { ref_mv->row >> 3, ref_mv->col >> 3 };
    int bestsme;
    int i;
    int interval = sf->mesh_patterns[0].interval;
    int range = sf->mesh_patterns[0].range;
    int baseline_interval_divisor;
  
    // Trap illegal values for interval and range for this function.
    if ((range < MIN_RANGE) || (range > MAX_RANGE) || (interval < MIN_INTERVAL) ||
        (interval > range))
      return INT_MAX;
  
    baseline_interval_divisor = range / interval;
  
    // Check size of proposed first range against magnitude of the centre
    // value used as a starting point.
    range = AOMMAX(range, (5 * AOMMAX(abs(temp_mv.row), abs(temp_mv.col))) / 4);
    range = AOMMIN(range, MAX_RANGE);
    interval = AOMMAX(interval, range / baseline_interval_divisor);
  
    // initial search
    bestsme = exhuastive_mesh_search(&cpi->common, x, &f_ref_mv, &temp_mv, range,
                                     interval, sadpb, fn_ptr, &temp_mv);
  
    if ((interval > MIN_INTERVAL) && (range > MIN_RANGE)) {
      // Progressive searches with range and step size decreasing each time
      // till we reach a step size of 1. Then break out.
      for (i = 1; i < MAX_MESH_STEP; ++i) {
        // First pass with coarser step and longer range
        bestsme = exhuastive_mesh_search(
            &cpi->common, x, &f_ref_mv, &temp_mv, sf->mesh_patterns[i].range,
            sf->mesh_patterns[i].interval, sadpb, fn_ptr, &temp_mv);
  
        if (sf->mesh_patterns[i].interval == 1) break;
      }
    }
  
    if (bestsme < INT_MAX)
      bestsme = av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr, 1);
    *dst_mv = temp_mv;
  
    // Return cost list.
    if (cost_list) {
      calc_int_cost_list(&cpi->common, x, ref_mv, sadpb, fn_ptr, dst_mv,
                         cost_list);
    }
    return bestsme;
  }
  
  // This function is called when we do joint motion search in comp_inter_inter
  // mode, or when searching for one component of an ext-inter compound mode.
  int av1_refining_search_8p_c(const AV1_COMMON *const cm, MACROBLOCK *x,
                               int error_per_bit, int search_range,
                               const aom_variance_fn_ptr_t *fn_ptr,
                               const uint8_t *mask, int mask_stride,
                               int invert_mask, const MV *center_mv,
                               const uint8_t *second_pred) {
    (void)cm;
    static const search_neighbors neighbors[8] = {
      { { -1, 0 }, -1 * SEARCH_GRID_STRIDE_8P + 0 },
      { { 0, -1 }, 0 * SEARCH_GRID_STRIDE_8P - 1 },
      { { 0, 1 }, 0 * SEARCH_GRID_STRIDE_8P + 1 },
      { { 1, 0 }, 1 * SEARCH_GRID_STRIDE_8P + 0 },
      { { -1, -1 }, -1 * SEARCH_GRID_STRIDE_8P - 1 },
      { { 1, -1 }, 1 * SEARCH_GRID_STRIDE_8P - 1 },
      { { -1, 1 }, -1 * SEARCH_GRID_STRIDE_8P + 1 },
      { { 1, 1 }, 1 * SEARCH_GRID_STRIDE_8P + 1 }
    };
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const struct buf_2d *const what = &x->plane[0].src;
    const struct buf_2d *const in_what = &xd->plane[0].pre[0];
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    MV *best_mv = &x->best_mv.as_mv;
    unsigned int best_sad = INT_MAX;
    int i, j;
    uint8_t do_refine_search_grid[SEARCH_GRID_STRIDE_8P *
                                  SEARCH_GRID_STRIDE_8P] = { 0 };
    int grid_center = SEARCH_GRID_CENTER_8P;
    int grid_coord = grid_center;
  
    clamp_mv(best_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    if (mask) {
      best_sad = fn_ptr->msdf(what->buf, what->stride,
                              get_buf_from_mv(in_what, best_mv), in_what->stride,
                              second_pred, mask, mask_stride, invert_mask) +
                 mvsad_err_cost(x, best_mv, &fcenter_mv, max_mv_precision,
                                error_per_bit);
    } else {
      best_sad =
          fn_ptr->sdaf(what->buf, what->stride, get_buf_from_mv(in_what, best_mv),
                       in_what->stride, second_pred) +
          mvsad_err_cost(x, best_mv, &fcenter_mv, max_mv_precision,
                         error_per_bit);
    }
  
    do_refine_search_grid[grid_coord] = 1;
  
    for (i = 0; i < search_range; ++i) {
      int best_site = -1;
  
      for (j = 0; j < 8; ++j) {
        grid_coord = grid_center + neighbors[j].coord_offset;
        if (do_refine_search_grid[grid_coord] == 1) {
          continue;
        }
        const MV mv = { best_mv->row + neighbors[j].coord.row,
                        best_mv->col + neighbors[j].coord.col };
  
        do_refine_search_grid[grid_coord] = 1;
        if (is_mv_in(&x->mv_limits, &mv)) {
          unsigned int sad;
          if (mask) {
            sad = fn_ptr->msdf(what->buf, what->stride,
                               get_buf_from_mv(in_what, &mv), in_what->stride,
                               second_pred, mask, mask_stride, invert_mask);
          } else {
            sad = fn_ptr->sdaf(what->buf, what->stride,
                               get_buf_from_mv(in_what, &mv), in_what->stride,
                               second_pred);
          }
          if (sad < best_sad) {
            sad += mvsad_err_cost(x, &mv, &fcenter_mv, max_mv_precision,
                                  error_per_bit);
            if (sad < best_sad) {
              best_sad = sad;
              best_site = j;
            }
          }
        }
      }
  
      if (best_site == -1) {
        break;
      } else {
        best_mv->row += neighbors[best_site].coord.row;
        best_mv->col += neighbors[best_site].coord.col;
        grid_center += neighbors[best_site].coord_offset;
      }
    }
    return best_sad;
  }
  
  static int vector_match(int16_t *ref, int16_t *src, int bwl) {
    int best_sad = INT_MAX;
    int this_sad;
    int d;
    int center, offset = 0;
    int bw = 4 << bwl;  // redundant variable, to be changed in the experiments.
    for (d = 0; d <= bw; d += 16) {
      this_sad = aom_vector_var(&ref[d], src, bwl);
      if (this_sad < best_sad) {
        best_sad = this_sad;
        offset = d;
      }
    }
    center = offset;
  
    for (d = -8; d <= 8; d += 16) {
      int this_pos = offset + d;
      // check limit
      if (this_pos < 0 || this_pos > bw) continue;
      this_sad = aom_vector_var(&ref[this_pos], src, bwl);
      if (this_sad < best_sad) {
        best_sad = this_sad;
        center = this_pos;
      }
    }
    offset = center;
  
    for (d = -4; d <= 4; d += 8) {
      int this_pos = offset + d;
      // check limit
      if (this_pos < 0 || this_pos > bw) continue;
      this_sad = aom_vector_var(&ref[this_pos], src, bwl);
      if (this_sad < best_sad) {
        best_sad = this_sad;
        center = this_pos;
      }
    }
    offset = center;
  
    for (d = -2; d <= 2; d += 4) {
      int this_pos = offset + d;
      // check limit
      if (this_pos < 0 || this_pos > bw) continue;
      this_sad = aom_vector_var(&ref[this_pos], src, bwl);
      if (this_sad < best_sad) {
        best_sad = this_sad;
        center = this_pos;
      }
    }
    offset = center;
  
    for (d = -1; d <= 1; d += 2) {
      int this_pos = offset + d;
      // check limit
      if (this_pos < 0 || this_pos > bw) continue;
      this_sad = aom_vector_var(&ref[this_pos], src, bwl);
      if (this_sad < best_sad) {
        best_sad = this_sad;
        center = this_pos;
      }
    }
  
    return (center - (bw >> 1));
  }
  
  static const MV search_pos[4] = {
    { -1, 0 },
    { 0, -1 },
    { 0, 1 },
    { 1, 0 },
  };
  
  unsigned int av1_int_pro_motion_estimation(const AV1_COMP *cpi, MACROBLOCK *x,
                                             BLOCK_SIZE bsize, int mi_row,
                                             int mi_col, const MV *ref_mv) {
    MACROBLOCKD *xd = &x->e_mbd;
    MB_MODE_INFO *mi = xd->mi[0];
    struct buf_2d backup_yv12[MAX_MB_PLANE] = { { 0, 0, 0, 0, 0 } };
    DECLARE_ALIGNED(16, int16_t, hbuf[256]);
    DECLARE_ALIGNED(16, int16_t, vbuf[256]);
    DECLARE_ALIGNED(16, int16_t, src_hbuf[128]);
    DECLARE_ALIGNED(16, int16_t, src_vbuf[128]);
    int idx;
    const int bw = 4 << mi_size_wide_log2[bsize];
    const int bh = 4 << mi_size_high_log2[bsize];
    const int search_width = bw << 1;
    const int search_height = bh << 1;
    const int src_stride = x->plane[0].src.stride;
    const int ref_stride = xd->plane[0].pre[0].stride;
    uint8_t const *ref_buf, *src_buf;
    MV *tmp_mv = &xd->mi[0]->mv[0].as_mv;
    unsigned int best_sad, tmp_sad, this_sad[4];
    MV this_mv;
    const int norm_factor = 3 + (bw >> 5);
    const YV12_BUFFER_CONFIG *scaled_ref_frame =
        av1_get_scaled_ref_frame(cpi, mi->ref_frame[0]);
    MvLimits subpel_mv_limits;
  
    if (scaled_ref_frame) {
      int i;
      // Swap out the reference frame for a version that's been scaled to
      // match the resolution of the current frame, allowing the existing
      // motion search code to be used without additional modifications.
      for (i = 0; i < MAX_MB_PLANE; i++) backup_yv12[i] = xd->plane[i].pre[0];
      av1_setup_pre_planes(xd, 0, scaled_ref_frame, mi_row, mi_col, NULL,
                           MAX_MB_PLANE, &mi->chroma_ref_info);
    }
  
    if (xd->bd != 8) {
      unsigned int sad;
      tmp_mv->row = 0;
      tmp_mv->col = 0;
      sad = cpi->fn_ptr[bsize].sdf(x->plane[0].src.buf, src_stride,
                                   xd->plane[0].pre[0].buf, ref_stride);
  
      if (scaled_ref_frame) {
        int i;
        for (i = 0; i < MAX_MB_PLANE; i++) xd->plane[i].pre[0] = backup_yv12[i];
      }
      return sad;
    }
  
    // Set up prediction 1-D reference set
    ref_buf = xd->plane[0].pre[0].buf - (bw >> 1);
    for (idx = 0; idx < search_width; idx += 16) {
      aom_int_pro_row(&hbuf[idx], ref_buf, ref_stride, bh);
      ref_buf += 16;
    }
  
    ref_buf = xd->plane[0].pre[0].buf - (bh >> 1) * ref_stride;
    for (idx = 0; idx < search_height; ++idx) {
      vbuf[idx] = aom_int_pro_col(ref_buf, bw) >> norm_factor;
      ref_buf += ref_stride;
    }
  
    // Set up src 1-D reference set
    for (idx = 0; idx < bw; idx += 16) {
      src_buf = x->plane[0].src.buf + idx;
      aom_int_pro_row(&src_hbuf[idx], src_buf, src_stride, bh);
    }
  
    src_buf = x->plane[0].src.buf;
    for (idx = 0; idx < bh; ++idx) {
      src_vbuf[idx] = aom_int_pro_col(src_buf, bw) >> norm_factor;
      src_buf += src_stride;
    }
  
    // Find the best match per 1-D search
    tmp_mv->col = vector_match(hbuf, src_hbuf, mi_size_wide_log2[bsize]);
    tmp_mv->row = vector_match(vbuf, src_vbuf, mi_size_high_log2[bsize]);
  
    this_mv = *tmp_mv;
    src_buf = x->plane[0].src.buf;
    ref_buf = xd->plane[0].pre[0].buf + this_mv.row * ref_stride + this_mv.col;
    best_sad = cpi->fn_ptr[bsize].sdf(src_buf, src_stride, ref_buf, ref_stride);
  
    {
      const uint8_t *const pos[4] = {
        ref_buf - ref_stride,
        ref_buf - 1,
        ref_buf + 1,
        ref_buf + ref_stride,
      };
  
      cpi->fn_ptr[bsize].sdx4df(src_buf, src_stride, pos, ref_stride, this_sad);
    }
  
    for (idx = 0; idx < 4; ++idx) {
      if (this_sad[idx] < best_sad) {
        best_sad = this_sad[idx];
        tmp_mv->row = search_pos[idx].row + this_mv.row;
        tmp_mv->col = search_pos[idx].col + this_mv.col;
      }
    }
  
    if (this_sad[0] < this_sad[3])
      this_mv.row -= 1;
    else
      this_mv.row += 1;
  
    if (this_sad[1] < this_sad[2])
      this_mv.col -= 1;
    else
      this_mv.col += 1;
  
    ref_buf = xd->plane[0].pre[0].buf + this_mv.row * ref_stride + this_mv.col;
  
    tmp_sad = cpi->fn_ptr[bsize].sdf(src_buf, src_stride, ref_buf, ref_stride);
    if (best_sad > tmp_sad) {
      *tmp_mv = this_mv;
      best_sad = tmp_sad;
    }
  
    tmp_mv->row *= 8;
    tmp_mv->col *= 8;
  
    set_subpel_mv_search_range(
        &x->mv_limits, &subpel_mv_limits.col_min, &subpel_mv_limits.col_max,
        &subpel_mv_limits.row_min, &subpel_mv_limits.row_max, ref_mv);
    clamp_mv(tmp_mv, subpel_mv_limits.col_min, subpel_mv_limits.col_max,
             subpel_mv_limits.row_min, subpel_mv_limits.row_max);
  
    if (scaled_ref_frame) {
      int i;
      for (i = 0; i < MAX_MB_PLANE; i++) xd->plane[i].pre[0] = backup_yv12[i];
    }
  
    return best_sad;
  }
  
  int av1_full_pixel_search(const AV1_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bsize,
                            MV *mvp_full, int step_param, int use_var, int method,
                            int run_mesh_search, int error_per_bit,
                            int *cost_list, const MV *ref_mv, int var_max, int rd,
                            int x_pos, int y_pos, int intra,
  #if CONFIG_EXT_IBC_MODES
                            IBC_MODE ibcMode,
  #endif  // CONFIG_EXT_IBC_MODES
                            const search_site_config *cfg) {
    const SPEED_FEATURES *const sf = &cpi->sf;
  #if CONFIG_EXT_IBC_MODES
    const aom_variance_fn_ptr_t *fn_ptr = NULL;
  
    // Non-square shape handling
    uint16_t width = block_size_wide[bsize];
    uint16_t height = block_size_high[bsize];
  
    if (width != height && (ibcMode == ROTATION_90 || ibcMode == ROTATION_270 ||
                            ibcMode == MIRROR_45 || ibcMode == MIRROR_135)) {
      if (bsize == BLOCK_8X4)
        fn_ptr = &cpi->fn_ptr[BLOCK_4X8];
      else if (bsize == BLOCK_4X8)
        fn_ptr = &cpi->fn_ptr[BLOCK_8X4];
      else if (bsize == BLOCK_8X16)
        fn_ptr = &cpi->fn_ptr[BLOCK_16X8];
      else if (bsize == BLOCK_16X8)
        fn_ptr = &cpi->fn_ptr[BLOCK_8X16];
      else if (bsize == BLOCK_32X16)
        fn_ptr = &cpi->fn_ptr[BLOCK_16X32];
      else if (bsize == BLOCK_16X32)
        fn_ptr = &cpi->fn_ptr[BLOCK_32X16];
      else if (bsize == BLOCK_32X64)
        fn_ptr = &cpi->fn_ptr[BLOCK_64X32];
      else if (bsize == BLOCK_64X32)
        fn_ptr = &cpi->fn_ptr[BLOCK_32X64];
      else if (bsize == BLOCK_128X64)
        fn_ptr = &cpi->fn_ptr[BLOCK_64X128];
      else if (bsize == BLOCK_64X128)
        fn_ptr = &cpi->fn_ptr[BLOCK_128X64];
      else if (bsize == BLOCK_4X16)
        fn_ptr = &cpi->fn_ptr[BLOCK_16X4];
      else if (bsize == BLOCK_16X4)
        fn_ptr = &cpi->fn_ptr[BLOCK_4X16];
      else if (bsize == BLOCK_32X8)
        fn_ptr = &cpi->fn_ptr[BLOCK_8X32];
      else if (bsize == BLOCK_8X32)
        fn_ptr = &cpi->fn_ptr[BLOCK_32X8];
      else if (bsize == BLOCK_64X16)
        fn_ptr = &cpi->fn_ptr[BLOCK_16X64];
      else if (bsize == BLOCK_16X64)
        fn_ptr = &cpi->fn_ptr[BLOCK_64X16];
    } else {
      fn_ptr = &cpi->fn_ptr[bsize];
    }
  #else
    const aom_variance_fn_ptr_t *fn_ptr = &cpi->fn_ptr[bsize];
  #endif  // CONFIG_EXT_IBC_MODES
    int var = 0;
  
    if (cost_list) {
      cost_list[0] = INT_MAX;
      cost_list[1] = INT_MAX;
      cost_list[2] = INT_MAX;
      cost_list[3] = INT_MAX;
      cost_list[4] = INT_MAX;
    }
  
    switch (method) {
      case FAST_DIAMOND:
        var = fast_dia_search(cpi, x, mvp_full, step_param, error_per_bit, 0,
                              cost_list, fn_ptr, 1, ref_mv);
        break;
      case FAST_HEX:
        var = fast_hex_search(cpi, x, mvp_full, step_param, error_per_bit, 0,
                              cost_list, fn_ptr, 1, ref_mv);
        break;
      case HEX:
        var = av1_hex_search(cpi, x, mvp_full, step_param, error_per_bit, 1,
                             cost_list, fn_ptr, 1, ref_mv);
        break;
      case SQUARE:
        var = square_search(cpi, x, mvp_full, step_param, error_per_bit, 1,
                            cost_list, fn_ptr, 1, ref_mv);
        break;
      case BIGDIA:
        var = bigdia_search(cpi, x, mvp_full, step_param, error_per_bit, 1,
                            cost_list, fn_ptr, 1, ref_mv);
        break;
      case NSTEP:
        var = full_pixel_diamond(cpi, x, mvp_full, step_param, use_var,
                                 error_per_bit, cfg->ss_count - 1 - step_param,
                                 cost_list, fn_ptr, ref_mv, cfg);
        break;
      default: assert(0 && "Invalid search method.");
    }
  
    // Should we allow a follow on exhaustive search?
    if (!run_mesh_search && method == NSTEP && use_var) {
      int exhuastive_thr = sf->exhaustive_searches_thresh;
      exhuastive_thr >>=
          10 - (mi_size_wide_log2[bsize] + mi_size_high_log2[bsize]);
      // Threshold variance for an exhaustive full search.
      if (var > exhuastive_thr) run_mesh_search = 1;
    }
  
    if (run_mesh_search) {
      int var_ex;
      MV tmp_mv_ex;
      var_ex = full_pixel_exhaustive(cpi, x, &x->best_mv.as_mv, error_per_bit,
                                     cost_list, fn_ptr, ref_mv, &tmp_mv_ex);
      if (var_ex < var) {
        var = var_ex;
        x->best_mv.as_mv = tmp_mv_ex;
      }
    }
  
    if (method != NSTEP && rd && var < var_max)
      var = av1_get_mvpred_var(&cpi->common, x, &x->best_mv.as_mv, ref_mv, fn_ptr,
                               1);
  
    do {
      if (!intra || !av1_use_hash_me(&cpi->common)) break;
  
      // already single ME
      // get block size and original buffer of current block
      const int block_height = block_size_high[bsize];
      const int block_width = block_size_wide[bsize];
      if (block_height == block_width && x_pos >= 0 && y_pos >= 0) {
        if (block_width == 4 || block_width == 8 || block_width == 16 ||
            block_width == 32 || block_width == 64 || block_width == 128) {
  #if CONFIG_EXT_IBC_MODES
          uint8_t *what = CONVERT_TO_BYTEPTR(x->ibc_src);
          const int what_stride = 128;  // Fixed stride (128x128 Scratch Buffer)
  #else
          uint8_t *what = x->plane[0].src.buf;
          const int what_stride = x->plane[0].src.stride;
  #endif  // CONFIG_EXT_IBC_MODES
  
          uint32_t hash_value1, hash_value2;
          MV best_hash_mv;
          int best_hash_cost = INT_MAX;
  
          // for the hashMap
          hash_table *ref_frame_hash =
              intra ? &cpi->common.cur_frame->hash_table
                    : av1_get_ref_frame_hash_map(&cpi->common,
                                                 x->e_mbd.mi[0]->ref_frame[0]);
  
          av1_get_block_hash_value(what, what_stride, block_width, &hash_value1,
                                   &hash_value2, is_cur_buf_hbd(&x->e_mbd), x);
  
          const int count = av1_hash_table_count(ref_frame_hash, hash_value1);
          // for intra, at lest one matching can be found, itself.
          if (count <= (intra ? 1 : 0)) {
            break;
          }
  
          Iterator iterator =
              av1_hash_get_first_iterator(ref_frame_hash, hash_value1);
          for (int i = 0; i < count; i++, aom_iterator_increment(&iterator)) {
            block_hash ref_block_hash =
                *(block_hash *)(aom_iterator_get(&iterator));
            if (hash_value2 == ref_block_hash.hash_value2) {
              // For intra, make sure the prediction is from valid area.
              if (intra) {
                const int mi_col = x_pos / MI_SIZE;
                const int mi_row = y_pos / MI_SIZE;
                const MV dv = { 8 * (ref_block_hash.y - y_pos),
                                8 * (ref_block_hash.x - x_pos) };
                if (!av1_is_dv_valid(dv, &cpi->common, &x->e_mbd, mi_row, mi_col,
                                     bsize, cpi->common.seq_params.mib_size_log2,
                                     &x->e_mbd.mi[0]->chroma_ref_info))
                  continue;
              }
              MV hash_mv;
              hash_mv.col = ref_block_hash.x - x_pos;
              hash_mv.row = ref_block_hash.y - y_pos;
              if (!is_mv_in(&x->mv_limits, &hash_mv)) continue;
              const int refCost = av1_get_mvpred_var(&cpi->common, x, &hash_mv,
                                                     ref_mv, fn_ptr, 1);
              if (refCost < best_hash_cost) {
                best_hash_cost = refCost;
                best_hash_mv = hash_mv;
              }
            }
          }
          if (best_hash_cost < var) {
            x->second_best_mv = x->best_mv;
            x->best_mv.as_mv = best_hash_mv;
            var = best_hash_cost;
          }
        }
      }
    } while (0);
  
    return var;
  }
  
  #define CHECK_BETTER(v, r, c)                                              \
    if (c >= minc && c <= maxc && r >= minr && r <= maxr) {                  \
      MV this_mv = { r, c };                                                 \
      thismse = vfp->osvf(pre(y, y_stride, r, c), y_stride, sp(c), sp(r), z, \
                          mask, &sse);                                       \
      v = mv_err_cost(&this_mv, *ref_mv, precision, min_precision, mvjcost,  \
                      mvcost, flex_mv_costs, error_per_bit, mv_cost_type);   \
      if ((v + thismse) < besterr) {                                         \
        besterr = v + thismse;                                               \
        br = r;                                                              \
        bc = c;                                                              \
        *distortion = thismse;                                               \
        *sse1 = sse;                                                         \
      }                                                                      \
    } else {                                                                 \
      v = INT_MAX;                                                           \
    }
  
  #undef CHECK_BETTER0
  #define CHECK_BETTER0(v, r, c) CHECK_BETTER(v, r, c)
  
  #undef CHECK_BETTER1
  #define CHECK_BETTER1(v, r, c)                                                \
    if (c >= minc && c <= maxc && r >= minr && r <= maxr) {                     \
      MV this_mv = { r, c };                                                    \
      thismse = upsampled_obmc_pref_error(xd, cm, mi_row, mi_col, &this_mv,     \
                                          mask, vfp, z, pre(y, y_stride, r, c), \
                                          y_stride, sp(c), sp(r), w, h, &sse,   \
                                          use_accurate_subpel_search);          \
      v = mv_err_cost(&this_mv, *ref_mv, precision, min_precision, mvjcost,     \
                      mvcost, flex_mv_costs, error_per_bit, mv_cost_type);      \
      if ((v + thismse) < besterr) {                                            \
        besterr = v + thismse;                                                  \
        br = r;                                                                 \
        bc = c;                                                                 \
        *distortion = thismse;                                                  \
        *sse1 = sse;                                                            \
      }                                                                         \
    } else {                                                                    \
      v = INT_MAX;                                                              \
    }
  
  static unsigned int setup_obmc_center_error(
      const int32_t *mask, const MV *bestmv, const MV *ref_mv, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, const int32_t *const wsrc,
      const uint8_t *const y, int y_stride, int offset,
      MvSubpelPrecision max_precision, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      unsigned int *sse1, int *distortion, MV_COST_TYPE mv_cost_type) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    unsigned int besterr;
    besterr = vfp->ovf(y + offset, y_stride, wsrc, mask, sse1);
    *distortion = besterr;
    besterr += mv_err_cost(bestmv, *ref_mv, max_precision, min_precision, mvjcost,
                           mvcost, flex_mv_costs, error_per_bit, mv_cost_type);
    return besterr;
  }
  
  static int upsampled_obmc_pref_error(
      MACROBLOCKD *xd, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *const mv, const int32_t *mask, const aom_variance_fn_ptr_t *vfp,
      const int32_t *const wsrc, const uint8_t *const y, int y_stride,
      int subpel_x_q3, int subpel_y_q3, int w, int h, unsigned int *sse,
      int subpel_search) {
    unsigned int besterr;
  
    DECLARE_ALIGNED(16, uint8_t, pred[2 * MAX_SB_SQUARE]);
    if (is_cur_buf_hbd(xd)) {
      uint8_t *pred8 = CONVERT_TO_BYTEPTR(pred);
      aom_highbd_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred8, w, h,
                                subpel_x_q3, subpel_y_q3, y, y_stride, xd->bd,
                                subpel_search);
      besterr = vfp->ovf(pred8, w, wsrc, mask, sse);
    } else {
      aom_upsampled_pred(xd, cm, mi_row, mi_col, mv, pred, w, h, subpel_x_q3,
                         subpel_y_q3, y, y_stride, subpel_search);
  
      besterr = vfp->ovf(pred, w, wsrc, mask, sse);
    }
    return besterr;
  }
  
  static unsigned int upsampled_setup_obmc_center_error(
      MACROBLOCKD *xd, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const int32_t *mask, const MV *bestmv, const MV *ref_mv, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, const int32_t *const wsrc,
      const uint8_t *const y, int y_stride, int w, int h, int offset,
      MvSubpelPrecision max_precision, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      unsigned int *sse1, int *distortion, int subpel_search,
      MV_COST_TYPE mv_cost_type) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // CONFIG_FLEX_MVRES
    unsigned int besterr = upsampled_obmc_pref_error(
        xd, cm, mi_row, mi_col, bestmv, mask, vfp, wsrc, y + offset, y_stride, 0,
        0, w, h, sse1, subpel_search);
    *distortion = besterr;
    besterr += mv_err_cost(bestmv, *ref_mv, max_precision, min_precision, mvjcost,
                           mvcost, flex_mv_costs, error_per_bit, mv_cost_type);
    return besterr;
  }
  
  int av1_find_best_obmc_sub_pixel_tree_up(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      MV *bestmv, const MV *ref_mv, MvSubpelPrecision precision,
      int error_per_bit, const aom_variance_fn_ptr_t *vfp, int forced_stop,
      int iters_per_step, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, int is_second,
      int use_accurate_subpel_search) {
  #if !CONFIG_FLEX_MVRES
    int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    MvSubpelPrecision min_precision = MV_SUBPEL_NONE;
  #endif  // !CONFIG_FLEX_MVRES
    const int32_t *wsrc = x->wsrc_buf;
    const int32_t *mask = x->mask_buf;
    const int *const z = wsrc;
    const int *const src_address = z;
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    MACROBLOCKD *xd = &x->e_mbd;
    struct macroblockd_plane *const pd = &xd->plane[0];
    MB_MODE_INFO *mbmi = xd->mi[0];
    unsigned int besterr = INT_MAX;
    unsigned int sse;
    unsigned int thismse;
  
    int br = bestmv->row * 8;
    int bc = bestmv->col * 8;
    int hstep = 4;
    int iter;
    int round = 3 - forced_stop;
    int tr = br;
    int tc = bc;
    const MV *search_step = search_step_table;
    int idx, best_idx = -1;
    unsigned int cost_array[5];
    int kr, kc;
    const int w = block_size_wide[mbmi->sb_type];
    const int h = block_size_high[mbmi->sb_type];
    int offset;
    int y_stride;
    const uint8_t *y;
  
    int minc, maxc, minr, maxr;
  
    set_subpel_mv_search_range(&x->mv_limits, &minc, &maxc, &minr, &maxr, ref_mv);
  
    y = pd->pre[is_second].buf;
    y_stride = pd->pre[is_second].stride;
    offset = bestmv->row * y_stride + bestmv->col;
  
    round = AOMMIN(round, (int)precision);
  
    bestmv->row *= 8;
    bestmv->col *= 8;
    // use_accurate_subpel_search can be 0 or 1 or 2
    if (use_accurate_subpel_search) {
      besterr = upsampled_setup_obmc_center_error(
          xd, cm, mi_row, mi_col, mask, bestmv, ref_mv, error_per_bit, vfp, z, y,
          y_stride, w, h, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
          flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
          sse1, distortion, use_accurate_subpel_search, mv_cost_type);
    } else {
      besterr =
          setup_obmc_center_error(mask, bestmv, ref_mv, error_per_bit, vfp, z, y,
                                  y_stride, offset, precision, mvjcost, mvcost,
  #if CONFIG_FLEX_MVRES
                                  flex_mv_costs, min_precision,
  #endif  // CONFIG_FLEX_MVRES
                                  sse1, distortion, mv_cost_type);
    }
  
    for (iter = 0; iter < round; ++iter) {
      // Check vertical and horizontal sub-pixel positions.
      for (idx = 0; idx < 4; ++idx) {
        tr = br + search_step[idx].row;
        tc = bc + search_step[idx].col;
        if (tc >= minc && tc <= maxc && tr >= minr && tr <= maxr) {
          MV this_mv = { tr, tc };
          if (use_accurate_subpel_search) {
            thismse = upsampled_obmc_pref_error(
                xd, cm, mi_row, mi_col, &this_mv, mask, vfp, src_address,
                pre(y, y_stride, tr, tc), y_stride, sp(tc), sp(tr), w, h, &sse,
                use_accurate_subpel_search);
          } else {
            thismse = vfp->osvf(pre(y, y_stride, tr, tc), y_stride, sp(tc),
                                sp(tr), src_address, mask, &sse);
          }
  
          cost_array[idx] =
              thismse + mv_err_cost(&this_mv, *ref_mv, precision, min_precision,
                                    mvjcost, mvcost, flex_mv_costs, error_per_bit,
                                    mv_cost_type);
          if (cost_array[idx] < besterr) {
            best_idx = idx;
            besterr = cost_array[idx];
            *distortion = thismse;
            *sse1 = sse;
          }
        } else {
          cost_array[idx] = INT_MAX;
        }
      }
  
      // Check diagonal sub-pixel position
      kc = (cost_array[0] <= cost_array[1] ? -hstep : hstep);
      kr = (cost_array[2] <= cost_array[3] ? -hstep : hstep);
  
      tc = bc + kc;
      tr = br + kr;
      if (tc >= minc && tc <= maxc && tr >= minr && tr <= maxr) {
        MV this_mv = { tr, tc };
  
        if (use_accurate_subpel_search) {
          thismse = upsampled_obmc_pref_error(
              xd, cm, mi_row, mi_col, &this_mv, mask, vfp, src_address,
              pre(y, y_stride, tr, tc), y_stride, sp(tc), sp(tr), w, h, &sse,
              use_accurate_subpel_search);
        } else {
          thismse = vfp->osvf(pre(y, y_stride, tr, tc), y_stride, sp(tc), sp(tr),
                              src_address, mask, &sse);
        }
  
        cost_array[4] =
            thismse + mv_err_cost(&this_mv, *ref_mv, precision, min_precision,
                                  mvjcost, mvcost, flex_mv_costs, error_per_bit,
                                  mv_cost_type);
  
        if (cost_array[4] < besterr) {
          best_idx = 4;
          besterr = cost_array[4];
          *distortion = thismse;
          *sse1 = sse;
        }
      } else {
        cost_array[idx] = INT_MAX;
      }
  
      if (best_idx < 4 && best_idx >= 0) {
        br += search_step[best_idx].row;
        bc += search_step[best_idx].col;
      } else if (best_idx == 4) {
        br = tr;
        bc = tc;
      }
  
      if (iters_per_step > 1 && best_idx != -1) {
        if (use_accurate_subpel_search) {
          SECOND_LEVEL_CHECKS_BEST(1);
        } else {
          SECOND_LEVEL_CHECKS_BEST(0);
        }
      }
  
      tr = br;
      tc = bc;
  
      search_step += 4;
      hstep >>= 1;
      best_idx = -1;
    }
  
    // These lines insure static analysis doesn't warn that
    // tr and tc aren't used after the above point.
    (void)tr;
    (void)tc;
  
    bestmv->row = br;
    bestmv->col = bc;
  
    return besterr;
  }
  
  #undef DIST
  #undef MVC
  #undef CHECK_BETTER
  
  static int get_obmc_mvpred_var(const AV1_COMMON *cm, const MACROBLOCK *x,
                                 const int32_t *wsrc, const int32_t *mask,
                                 const MV *best_mv, const MV *center_mv,
                                 const aom_variance_fn_ptr_t *vfp, int use_mvcost,
                                 int is_second) {
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const struct buf_2d *const in_what = &xd->plane[0].pre[is_second];
    const MV mv = { best_mv->row * 8, best_mv->col * 8 };
    const MV_COST_TYPE mv_cost_type = x->mv_cost_type;
    unsigned int unused;
    const int(*flex_mv_costs)[FLEX_MV_COSTS_SIZE] = NULL;
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  #if CONFIG_FLEX_MVRES
    const int use_flex_mv =
        is_pb_mv_precision_active(cm, mbmi->mode, mbmi->max_mv_precision);
    const int down_ctx = av1_get_pb_mv_precision_down_context(cm, xd);
    flex_mv_costs = use_flex_mv ? x->pb_mv_precision_costs[down_ctx] : NULL;
  #else
    (void)cm;
  #endif  // CONFIG_FLEX_MVRES
  
    return vfp->ovf(get_buf_from_mv(in_what, best_mv), in_what->stride, wsrc,
                    mask, &unused) +
           (use_mvcost ? mv_err_cost(&mv, *center_mv, max_mv_precision,
                                     MV_SUBPEL_NONE, x->nmv_vec_cost, x->nmvcost,
                                     flex_mv_costs, x->errorperbit, mv_cost_type)
                       : 0);
  }
  
  static int obmc_refining_search_sad(const AV1_COMMON *const cm,
                                      const MACROBLOCK *x, const int32_t *wsrc,
                                      const int32_t *mask, MV *ref_mv,
                                      int error_per_bit, int search_range,
                                      const aom_variance_fn_ptr_t *fn_ptr,
                                      const MV *center_mv, int is_second) {
    (void)cm;
    const MV neighbors[4] = { { -1, 0 }, { 0, -1 }, { 0, 1 }, { 1, 0 } };
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const struct buf_2d *const in_what = &xd->plane[0].pre[is_second];
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    unsigned int best_sad =
        fn_ptr->osdf(get_buf_from_mv(in_what, ref_mv), in_what->stride, wsrc,
                     mask) +
        mvsad_err_cost(x, ref_mv, &fcenter_mv, max_mv_precision, error_per_bit);
    int i, j;
  
    for (i = 0; i < search_range; i++) {
      int best_site = -1;
  
      for (j = 0; j < 4; j++) {
        const MV mv = { ref_mv->row + neighbors[j].row,
                        ref_mv->col + neighbors[j].col };
        if (is_mv_in(&x->mv_limits, &mv)) {
          unsigned int sad = fn_ptr->osdf(get_buf_from_mv(in_what, &mv),
                                          in_what->stride, wsrc, mask);
          if (sad < best_sad) {
            sad += mvsad_err_cost(x, &mv, &fcenter_mv, max_mv_precision,
                                  error_per_bit);
            if (sad < best_sad) {
              best_sad = sad;
              best_site = j;
            }
          }
        }
      }
  
      if (best_site == -1) {
        break;
      } else {
        ref_mv->row += neighbors[best_site].row;
        ref_mv->col += neighbors[best_site].col;
      }
    }
    return best_sad;
  }
  
  static int obmc_diamond_search_sad(
      const AV1_COMMON *const cm, const MACROBLOCK *x,
      const search_site_config *cfg, const int32_t *wsrc, const int32_t *mask,
      MV *ref_mv, MV *best_mv, int search_param, int sad_per_bit, int *num00,
      const aom_variance_fn_ptr_t *fn_ptr, const MV *center_mv, int is_second) {
    (void)cm;
    const MACROBLOCKD *const xd = &x->e_mbd;
    const MB_MODE_INFO *mbmi = xd->mi[0];
    const struct buf_2d *const in_what = &xd->plane[0].pre[is_second];
  
    // search_param determines the length of the initial step and hence the
    // number of iterations 0 = initial step (MAX_FIRST_STEP) pel : 1 =
    // (MAX_FIRST_STEP/2) pel, 2 = (MAX_FIRST_STEP/4) pel... etc.
    const int tot_steps = MAX_MVSEARCH_STEPS - 1 - search_param;
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    const MvSubpelPrecision max_mv_precision = mbmi->max_mv_precision;
  
    const uint8_t *best_address, *in_what_ref;
    int best_sad = INT_MAX;
    int best_site = 0;
    int step;
  
    clamp_mv(ref_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    in_what_ref = in_what->buf + ref_mv->row * in_what->stride + ref_mv->col;
    best_address = in_what_ref;
    *num00 = 0;
    *best_mv = *ref_mv;
  
    // Check the starting position
    best_sad =
        fn_ptr->osdf(best_address, in_what->stride, wsrc, mask) +
        mvsad_err_cost(x, best_mv, &fcenter_mv, max_mv_precision, sad_per_bit);
  
    for (step = tot_steps; step >= 0; --step) {
      const search_site *const ss = cfg->ss[step];
      best_site = 0;
      for (int idx = 1; idx <= cfg->searches_per_step[step]; ++idx) {
        const MV mv = { best_mv->row + ss[idx].mv.row,
                        best_mv->col + ss[idx].mv.col };
        if (is_mv_in(&x->mv_limits, &mv)) {
          int sad = fn_ptr->osdf(best_address + ss[idx].offset, in_what->stride,
                                 wsrc, mask);
          if (sad < best_sad) {
            sad += mvsad_err_cost(x, &mv, &fcenter_mv, max_mv_precision,
                                  sad_per_bit);
            if (sad < best_sad) {
              best_sad = sad;
              best_site = idx;
            }
          }
        }
      }
  
      if (best_site != 0) {
        best_mv->row += ss[best_site].mv.row;
        best_mv->col += ss[best_site].mv.col;
        best_address += ss[best_site].offset;
      } else if (best_address == in_what_ref) {
        (*num00)++;
      }
    }
    return best_sad;
  }
  
  static int obmc_full_pixel_diamond(const AV1_COMP *cpi, MACROBLOCK *x,
                                     MV *mvp_full, int step_param, int sadpb,
                                     int further_steps, int do_refine,
                                     const aom_variance_fn_ptr_t *fn_ptr,
                                     const MV *ref_mv, MV *dst_mv, int is_second,
                                     const search_site_config *cfg) {
    const AV1_COMMON *cm = &cpi->common;
    const int32_t *wsrc = x->wsrc_buf;
    const int32_t *mask = x->mask_buf;
    MV temp_mv;
    int thissme, n, num00 = 0;
    int bestsme =
        obmc_diamond_search_sad(cm, x, cfg, wsrc, mask, mvp_full, &temp_mv,
                                step_param, sadpb, &n, fn_ptr, ref_mv, is_second);
    if (bestsme < INT_MAX)
      bestsme = get_obmc_mvpred_var(cm, x, wsrc, mask, &temp_mv, ref_mv, fn_ptr,
                                    1, is_second);
    *dst_mv = temp_mv;
  
    // If there won't be more n-step search, check to see if refining search is
    // needed.
    if (n > further_steps) do_refine = 0;
  
    while (n < further_steps) {
      ++n;
  
      if (num00) {
        num00--;
      } else {
        thissme = obmc_diamond_search_sad(cm, x, cfg, wsrc, mask, mvp_full,
                                          &temp_mv, step_param + n, sadpb, &num00,
                                          fn_ptr, ref_mv, is_second);
        if (thissme < INT_MAX)
          thissme = get_obmc_mvpred_var(cm, x, wsrc, mask, &temp_mv, ref_mv,
                                        fn_ptr, 1, is_second);
  
        // check to see if refining search is needed.
        if (num00 > further_steps - n) do_refine = 0;
  
        if (thissme < bestsme) {
          bestsme = thissme;
          *dst_mv = temp_mv;
        }
      }
    }
  
    // final 1-away diamond refining search
    if (do_refine) {
      const int search_range = 8;
      MV best_mv = *dst_mv;
      thissme = obmc_refining_search_sad(cm, x, wsrc, mask, &best_mv, sadpb,
                                         search_range, fn_ptr, ref_mv, is_second);
      if (thissme < INT_MAX)
        thissme = get_obmc_mvpred_var(cm, x, wsrc, mask, &best_mv, ref_mv, fn_ptr,
                                      1, is_second);
      if (thissme < bestsme) {
        bestsme = thissme;
        *dst_mv = best_mv;
      }
    }
    return bestsme;
  }
  
  int av1_obmc_full_pixel_search(const AV1_COMP *cpi, MACROBLOCK *x, MV *mvp_full,
                                 int step_param, int sadpb, int further_steps,
                                 int do_refine,
                                 const aom_variance_fn_ptr_t *fn_ptr,
                                 const MV *ref_mv, MV *dst_mv, int is_second,
                                 const search_site_config *cfg) {
    if (cpi->sf.obmc_full_pixel_search_level == 0) {
      return obmc_full_pixel_diamond(cpi, x, mvp_full, step_param, sadpb,
                                     further_steps, do_refine, fn_ptr, ref_mv,
                                     dst_mv, is_second, cfg);
    } else {
      const int32_t *wsrc = x->wsrc_buf;
      const int32_t *mask = x->mask_buf;
      const int search_range = 8;
      *dst_mv = *mvp_full;
      clamp_mv(dst_mv, x->mv_limits.col_min, x->mv_limits.col_max,
               x->mv_limits.row_min, x->mv_limits.row_max);
      int thissme =
          obmc_refining_search_sad(&cpi->common, x, wsrc, mask, dst_mv, sadpb,
                                   search_range, fn_ptr, ref_mv, is_second);
      if (thissme < INT_MAX)
        thissme = get_obmc_mvpred_var(&cpi->common, x, wsrc, mask, dst_mv, ref_mv,
                                      fn_ptr, 1, is_second);
      return thissme;
    }
  }
  
  // Note(yunqingwang): The following 2 functions are only used in the motion
  // vector unit test, which return extreme motion vectors allowed by the MV
  // limits.
  #define COMMON_MV_TEST              \
    SETUP_SUBPEL_SEARCH;              \
                                      \
    (void)error_per_bit;              \
    (void)vfp;                        \
    (void)src_address;                \
    (void)src_stride;                 \
    (void)y;                          \
    (void)y_stride;                   \
    (void)second_pred;                \
    (void)w;                          \
    (void)h;                          \
    (void)use_accurate_subpel_search; \
    (void)offset;                     \
    (void)mvjcost;                    \
    (void)mvcost;                     \
    (void)sse1;                       \
    (void)distortion;                 \
                                      \
    (void)halfiters;                  \
    (void)quarteriters;               \
    (void)eighthiters;                \
    (void)whichdir;                   \
    (void)forced_stop;                \
    (void)hstep;                      \
                                      \
    (void)tr;                         \
    (void)tc;                         \
    (void)sse;                        \
    (void)thismse;                    \
    (void)cost_list;
  // Return the maximum MV.
  int av1_return_max_sub_pixel_mv(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if CONFIG_FLEX_MVRES
    (void)flex_mv_costs;
    (void)min_precision;
  #endif  // CONFIG_FLEX_MVRES
    COMMON_MV_TEST;
    (void)mask;
    (void)mask_stride;
    (void)invert_mask;
    (void)minr;
    (void)minc;
  
    (void)cm;
    (void)mi_row;
    (void)mi_col;
    (void)do_reset_fractional_mv;
    (void)mv_cost_type;
  
    bestmv->row = maxr;
    bestmv->col = maxc;
    besterr = 0;
    // In the sub-pel motion search, if hp is not used, then the last bit of mv
    // has to be 0.
    lower_mv_precision(bestmv, precision);
    return besterr;
  }
  // Return the minimum MV.
  int av1_return_min_sub_pixel_mv(
      MACROBLOCK *x, const AV1_COMMON *const cm, int mi_row, int mi_col,
      const MV *ref_mv, MvSubpelPrecision precision, int error_per_bit,
      const aom_variance_fn_ptr_t *vfp, int forced_stop, int iters_per_step,
      int *cost_list, int *mvjcost, int *(*mvcost)[2],
  #if CONFIG_FLEX_MVRES
      int (*flex_mv_costs)[FLEX_MV_COSTS_SIZE], MvSubpelPrecision min_precision,
  #endif  // CONFIG_FLEX_MVRES
      int *distortion, unsigned int *sse1, const uint8_t *second_pred,
      const uint8_t *mask, int mask_stride, int invert_mask, int w, int h,
      int use_accurate_subpel_search, const int do_reset_fractional_mv) {
  #if CONFIG_FLEX_MVRES
    (void)flex_mv_costs;
    (void)min_precision;
  #endif  // CONFIG_FLEX_MVRES
    COMMON_MV_TEST;
    (void)maxr;
    (void)maxc;
    (void)mask;
    (void)mask_stride;
    (void)invert_mask;
  
    (void)cm;
    (void)mi_row;
    (void)mi_col;
    (void)do_reset_fractional_mv;
    (void)mv_cost_type;
  
    bestmv->row = minr;
    bestmv->col = minc;
    besterr = 0;
    // In the sub-pel motion search, if hp is not used, then the last bit of mv
    // has to be 0.
    lower_mv_precision(bestmv, precision);
    return besterr;
  }
  
  void av1_simple_motion_search(AV1_COMP *const cpi, MACROBLOCK *x, int mi_row,
                                int mi_col, BLOCK_SIZE bsize, int ref,
                                MV ref_mv_full, int num_planes,
                                int use_subpixel) {
    assert(num_planes == 1 &&
           "Currently simple_motion_search only supports luma plane");
    assert(!frame_is_intra_only(&cpi->common) &&
           "Simple motion search only enabled for non-key frames");
    AV1_COMMON *const cm = &cpi->common;
    MACROBLOCKD *xd = &x->e_mbd;
  
    set_offsets_for_motion_search(cpi, x, mi_row, mi_col, bsize);
  
    MB_MODE_INFO *mbmi = xd->mi[0];
    mbmi->sb_type = bsize;
    mbmi->ref_frame[0] = ref;
    mbmi->ref_frame[1] = NONE_FRAME;
    mbmi->motion_mode = SIMPLE_TRANSLATION;
    mbmi->mode = NEWMV;
  #if CONFIG_DERIVED_MV
    mbmi->derived_mv_allowed = mbmi->use_derived_mv = 0;
  #endif  // CONFIG_DERIVED_MV
    set_default_mbmi_mv_precision(cm, mbmi, xd->sbi);
    mbmi->interp_filters = av1_broadcast_interp_filter(EIGHTTAP_REGULAR);
  
    const YV12_BUFFER_CONFIG *yv12 = get_ref_frame_yv12_buf(cm, ref);
    const YV12_BUFFER_CONFIG *scaled_ref_frame =
        av1_get_scaled_ref_frame(cpi, ref);
    struct buf_2d backup_yv12;
    // ref_mv is used to code the motion vector. ref_mv_full is the initial
    // point. ref_mv is in units of 1/8 pel whereas ref_mv_full is in units of
    // pel.
    MV ref_mv = { 0, 0 };
    const int step_param = cpi->mv_step_param;
    const MvLimits tmp_mv_limits = x->mv_limits;
    const SEARCH_METHODS search_methods = cpi->sf.mv.search_method;
    const int do_mesh_search = 0;
    const int sadpb = x->sadperbit16;
    int cost_list[5];
    const int ref_idx = 0;
    int var;
  
    av1_setup_pre_planes(xd, ref_idx, yv12, mi_row, mi_col,
                         get_ref_scale_factors(cm, ref), num_planes,
                         &mbmi->chroma_ref_info);
    set_ref_ptrs(cm, xd, mbmi->ref_frame[0], mbmi->ref_frame[1]);
    if (scaled_ref_frame) {
      backup_yv12 = xd->plane[AOM_PLANE_Y].pre[ref_idx];
      av1_setup_pre_planes(xd, ref_idx, scaled_ref_frame, mi_row, mi_col, NULL,
                           num_planes, &mbmi->chroma_ref_info);
    }
  
    // This overwrites the mv_limits so we will need to restore it later.
    av1_set_mv_search_range(&x->mv_limits, &ref_mv);
  
    var = av1_full_pixel_search(cpi, x, bsize, &ref_mv_full, step_param, 1,
                                search_methods, do_mesh_search, sadpb,
                                cond_cost_list(cpi, cost_list), &ref_mv, INT_MAX,
                                1, mi_col * MI_SIZE, mi_row * MI_SIZE, 0,
  #if CONFIG_EXT_IBC_MODES
                                0,
  #endif  // CONFIG_EXT_IBC_MODES
                                &cpi->ss_cfg[SS_CFG_SRC]);
  
    // Restore
    x->mv_limits = tmp_mv_limits;
  
    const int use_subpel_search =
        var < INT_MAX && !cpi->common.cur_frame_force_integer_mv && use_subpixel;
    if (scaled_ref_frame) {
      xd->plane[AOM_PLANE_Y].pre[ref_idx] = backup_yv12;
    }
    if (use_subpel_search) {
      int not_used = 0;
      const MvSubpelPrecision max_mv_precision = mbmi->pb_mv_precision;
      if (cpi->sf.use_accurate_subpel_search) {
        const int pw = block_size_wide[bsize];
        const int ph = block_size_high[bsize];
        cpi->find_fractional_mv_step(
            x, cm, mi_row, mi_col, &ref_mv, max_mv_precision, x->errorperbit,
            &cpi->fn_ptr[bsize], cpi->sf.mv.subpel_force_stop,
            cpi->sf.mv.subpel_iters_per_step, cond_cost_list(cpi, cost_list),
            x->nmv_vec_cost, x->nmvcost,
  #if CONFIG_FLEX_MVRES
            NULL, MV_SUBPEL_NONE,
  #endif  // CONFIG_FLEX_MVRES
            &not_used, &x->pred_sse[ref], NULL, NULL, 0, 0, pw, ph,
            cpi->sf.use_accurate_subpel_search, 1);
      } else {
        cpi->find_fractional_mv_step(
            x, cm, mi_row, mi_col, &ref_mv, max_mv_precision, x->errorperbit,
            &cpi->fn_ptr[bsize], cpi->sf.mv.subpel_force_stop,
            cpi->sf.mv.subpel_iters_per_step, cond_cost_list(cpi, cost_list),
            x->nmv_vec_cost, x->nmvcost,
  #if CONFIG_FLEX_MVRES
            NULL, MV_SUBPEL_NONE,
  #endif  // CONFIG_FLEX_MVRES
            &not_used, &x->pred_sse[ref], NULL, NULL, 0, 0, 0, 0, 0, 1);
      }
    } else {
      // Manually convert from units of pixel to 1/8-pixels if we are not doing
      // subpel search
      x->best_mv.as_mv.row *= 8;
      x->best_mv.as_mv.col *= 8;
    }
  
    mbmi->mv[0].as_mv = x->best_mv.as_mv;
  
    // Get a copy of the prediction output
    av1_enc_build_inter_predictor(cm, xd, mi_row, mi_col, NULL, bsize,
                                  AOM_PLANE_Y, AOM_PLANE_Y);
  
    aom_clear_system_state();
  
    if (scaled_ref_frame) {
      xd->plane[AOM_PLANE_Y].pre[ref_idx] = backup_yv12;
    }
  }
  
  #if CONFIG_EXT_RECUR_PARTITIONS
  void av1_simple_motion_search_ext(AV1_COMP *const cpi,
                                    const TileInfo *const tile, MACROBLOCK *x,
                                    CHROMA_REF_INFO *chr_ref_info, int mi_row,
                                    int mi_col, BLOCK_SIZE bsize, int ref_frame,
                                    MV start_mv, SimpleMotionData *sms_data) {
    assert(!frame_is_intra_only(&cpi->common) &&
           "Simple motion search only enabled for non-key frames");
    AV1_COMMON *const cm = &cpi->common;
    MACROBLOCKD *xd = &x->e_mbd;
  
    av1_enc_set_offsets(cpi, tile, x, mi_row, mi_col, bsize, chr_ref_info);
  
    MB_MODE_INFO *mbmi = xd->mi[0];
    mbmi->sb_type = bsize;
    mbmi->ref_frame[0] = ref_frame;
    mbmi->ref_frame[1] = NONE_FRAME;
    mbmi->motion_mode = SIMPLE_TRANSLATION;
    mbmi->mode = NEWMV;
    set_default_mbmi_mv_precision(cm, mbmi, xd->sbi);
    mbmi->interp_filters = av1_broadcast_interp_filter(EIGHTTAP_REGULAR);
  
    const int num_planes = 1;
    const YV12_BUFFER_CONFIG *yv12 = get_ref_frame_yv12_buf(cm, ref_frame);
    const YV12_BUFFER_CONFIG *scaled_ref_frame =
        av1_get_scaled_ref_frame(cpi, ref_frame);
    struct buf_2d backup_yv12;
    // ref_mv is used to code the motion vector. start_mv is the initial
    // point. ref_mv is in units of 1/8 pel whereas start_mv is in units of
    // pel.
    MV ref_mv = { 0, 0 };
    const int step_param = cpi->mv_step_param;
    const MvLimits tmp_mv_limits = x->mv_limits;
    const SEARCH_METHODS search_methods = cpi->sf.mv.search_method;
    const int do_mesh_search = 0;
    const int sadpb = x->sadperbit16;
    int cost_list[5];
    const int ref_idx = 0;
    int var;
  
    av1_setup_pre_planes(xd, ref_idx, yv12, mi_row, mi_col,
                         get_ref_scale_factors(cm, ref_frame), num_planes,
                         chr_ref_info);
    set_ref_ptrs(cm, xd, mbmi->ref_frame[0], mbmi->ref_frame[1]);
    if (scaled_ref_frame) {
      backup_yv12 = xd->plane[AOM_PLANE_Y].pre[ref_idx];
      av1_setup_pre_planes(xd, ref_idx, scaled_ref_frame, mi_row, mi_col, NULL,
                           num_planes, chr_ref_info);
    }
  
    // This overwrites the mv_limits so we will need to restore it later.
    av1_set_mv_search_range(&x->mv_limits, &ref_mv);
  
    sms_data->mv_cost_type = x->mv_cost_type;
    sms_data->sadpb = sadpb;
    sms_data->errorperbit = x->errorperbit;
    sms_data->mv_precision = mbmi->max_mv_precision;
  
    var = av1_full_pixel_search(cpi, x, bsize, &start_mv, step_param, 1,
                                search_methods, do_mesh_search, sadpb,
                                cond_cost_list(cpi, cost_list), &ref_mv, INT_MAX,
                                1, mi_col * MI_SIZE, mi_row * MI_SIZE, 0,
  #if CONFIG_EXT_IBC_MODES
                                0,
  #endif  // CONFIG_EXT_IBC_MODES
                                &cpi->ss_cfg[SS_CFG_SRC]);
  
    sms_data->fullmv = x->best_mv.as_mv;
    // Restore
    x->mv_limits = tmp_mv_limits;
  
    const int use_subpel_search =
        var < INT_MAX && !cpi->common.cur_frame_force_integer_mv;
    if (scaled_ref_frame) {
      xd->plane[AOM_PLANE_Y].pre[ref_idx] = backup_yv12;
    }
    if (use_subpel_search) {
      int not_used = 0;
      const MvSubpelPrecision max_mv_precision = mbmi->pb_mv_precision;
      if (cpi->sf.use_accurate_subpel_search) {
        const int pw = block_size_wide[bsize];
        const int ph = block_size_high[bsize];
        cpi->find_fractional_mv_step(
            x, cm, mi_row, mi_col, &ref_mv, max_mv_precision, x->errorperbit,
            &cpi->fn_ptr[bsize], cpi->sf.mv.subpel_force_stop,
            cpi->sf.mv.subpel_iters_per_step, cond_cost_list(cpi, cost_list),
            x->nmv_vec_cost, x->nmvcost,
  #if CONFIG_FLEX_MVRES
            NULL, MV_SUBPEL_NONE,
  #endif  // CONFIG_FLEX_MVRES
            &not_used, &x->pred_sse[ref_frame], NULL, NULL, 0, 0, pw, ph,
            cpi->sf.use_accurate_subpel_search, 1);
      } else {
        cpi->find_fractional_mv_step(
            x, cm, mi_row, mi_col, &ref_mv, max_mv_precision, x->errorperbit,
            &cpi->fn_ptr[bsize], cpi->sf.mv.subpel_force_stop,
            cpi->sf.mv.subpel_iters_per_step, cond_cost_list(cpi, cost_list),
            x->nmv_vec_cost, x->nmvcost,
  #if CONFIG_FLEX_MVRES
            NULL, MV_SUBPEL_NONE,
  #endif  // CONFIG_FLEX_MVRES
            &not_used, &x->pred_sse[ref_frame], NULL, NULL, 0, 0, 0, 0, 0, 1);
      }
    } else {
      // Manually convert from units of pixel to 1/8-pixels if we are not doing
      // subpel search
      x->best_mv.as_mv.row *= 8;
      x->best_mv.as_mv.col *= 8;
    }
  
    sms_data->submv = x->best_mv.as_mv;
    mbmi->mv[0].as_mv = x->best_mv.as_mv;
  
    // Get a copy of the prediction output
    av1_enc_build_inter_predictor(cm, xd, mi_row, mi_col, NULL, bsize,
                                  AOM_PLANE_Y, AOM_PLANE_Y);
  
    aom_clear_system_state();
  
    if (scaled_ref_frame) {
      xd->plane[AOM_PLANE_Y].pre[ref_idx] = backup_yv12;
    }
  }
  #endif  // CONFIG_EXT_RECUR_PARTITIONS
  
  void av1_simple_motion_sse_var(AV1_COMP *cpi, MACROBLOCK *x, int mi_row,
                                 int mi_col, BLOCK_SIZE bsize,
                                 const MV ref_mv_full, int use_subpixel,
                                 unsigned int *sse, unsigned int *var) {
    MACROBLOCKD *xd = &x->e_mbd;
    const MV_REFERENCE_FRAME ref =
        cpi->rc.is_src_frame_alt_ref ? ALTREF_FRAME : LAST_FRAME;
  
    av1_simple_motion_search(cpi, x, mi_row, mi_col, bsize, ref, ref_mv_full, 1,
                             use_subpixel);
  
    const uint8_t *src = x->plane[0].src.buf;
    const int src_stride = x->plane[0].src.stride;
    const uint8_t *dst = xd->plane[0].dst.buf;
    const int dst_stride = xd->plane[0].dst.stride;
  
    *var = cpi->fn_ptr[bsize].vf(src, src_stride, dst, dst_stride, sse);
  }
  
  // Exhaustive motion search around a given centre position with a given
  // step size.
  static int exhaustive_mesh_search_var(const AV1_COMMON *cm, MACROBLOCK *x,
                                        MV *ref_mv, MV *best_mv, int range,
                                        int step,
                                        const aom_variance_fn_ptr_t *fn_ptr,
                                        const MV *center_mv) {
    MV fcenter_mv = { center_mv->row, center_mv->col };
    int start_col, end_col, start_row, end_row;
    assert(step >= 1);
  
    clamp_mv(&fcenter_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    *best_mv = fcenter_mv;
    unsigned int best_var =
        av1_get_mvpred_var(cm, x, &fcenter_mv, ref_mv, fn_ptr, 1);
    start_row = AOMMAX(-range, x->mv_limits.row_min - fcenter_mv.row);
    start_col = AOMMAX(-range, x->mv_limits.col_min - fcenter_mv.col);
    end_row = AOMMIN(range, x->mv_limits.row_max - fcenter_mv.row);
    end_col = AOMMIN(range, x->mv_limits.col_max - fcenter_mv.col);
  
    for (int r = start_row; r <= end_row; r += step) {
      for (int c = start_col; c <= end_col; c += step) {
        const MV mv = { fcenter_mv.row + r, fcenter_mv.col + c };
        unsigned int var = av1_get_mvpred_var(cm, x, &mv, ref_mv, fn_ptr, 1);
        if (var < best_var) {
          best_var = var;
          x->second_best_mv.as_mv = *best_mv;
          *best_mv = mv;
        }
      }
    }
    return best_var;
  }
  
  static int diamond_search_var(const AV1_COMMON *cm, MACROBLOCK *x,
                                const search_site_config *cfg, MV *ref_mv,
                                MV *best_mv, int search_param, int *num00,
                                const aom_variance_fn_ptr_t *fn_ptr,
                                const MV *center_mv) {
    int step;
    const MACROBLOCKD *const xd = &x->e_mbd;
    const uint8_t *in_what;
    const int in_what_stride = xd->plane[0].pre[0].stride;
    const uint8_t *best_address;
  
    unsigned int bestvar = INT_MAX;
    int best_site = 0;
  
    int ref_row;
    int ref_col;
  
    // search_param determines the length of the initial step and hence the
    // number of iterations. 0 = initial step (MAX_FIRST_STEP) pel 1 =
    // (MAX_FIRST_STEP/2) pel, 2 = (MAX_FIRST_STEP/4) pel...
    const int tot_steps = cfg->ss_count - 1 - search_param;
  
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    clamp_mv(ref_mv, x->mv_limits.col_min, x->mv_limits.col_max,
             x->mv_limits.row_min, x->mv_limits.row_max);
    ref_row = ref_mv->row;
    ref_col = ref_mv->col;
    *num00 = 0;
    best_mv->row = ref_row;
    best_mv->col = ref_col;
  
    // Work out the start point for the search
    in_what = xd->plane[0].pre[0].buf + ref_row * in_what_stride + ref_col;
    best_address = in_what;
  
    // Check the starting position
    bestvar = av1_get_mvpred_var(cm, x, best_mv, &fcenter_mv, fn_ptr, 1);
  
    for (step = tot_steps; step >= 0; --step) {
      const search_site *const ss = cfg->ss[step];
      best_site = 0;
      for (int idx = 1; idx <= cfg->searches_per_step[step]; ++idx) {
        // Trap illegal vectors
        const MV this_mv = { best_mv->row + ss[idx].mv.row,
                             best_mv->col + ss[idx].mv.col };
  
        if (is_mv_in(&x->mv_limits, &this_mv)) {
          unsigned int thisvar =
              av1_get_mvpred_var(cm, x, &this_mv, &fcenter_mv, fn_ptr, 1);
          if (thisvar < bestvar) {
            bestvar = thisvar;
            best_site = idx;
          }
        }
      }
  
      if (best_site != 0) {
        x->second_best_mv.as_mv = *best_mv;
        best_mv->row += ss[best_site].mv.row;
        best_mv->col += ss[best_site].mv.col;
        best_address += ss[best_site].offset;
      } else if (best_address == in_what) {
        (*num00)++;
      }
    }
    return bestvar;
  }
  
  static int refining_search_var(const AV1_COMMON *cm, MACROBLOCK *x, MV *ref_mv,
                                 int search_range,
                                 const aom_variance_fn_ptr_t *fn_ptr,
                                 const MV *center_mv) {
    const MV neighbors[4] = { { -1, 0 }, { 0, -1 }, { 0, 1 }, { 1, 0 } };
    const MV fcenter_mv = { center_mv->row >> 3, center_mv->col >> 3 };
    unsigned int bestvar =
        av1_get_mvpred_var(cm, x, &fcenter_mv, ref_mv, fn_ptr, 1);
    int i, j;
  
    for (i = 0; i < search_range; i++) {
      int best_site = -1;
      for (j = 0; j < 4; ++j) {
        const MV mv = { ref_mv->row + neighbors[j].row,
                        ref_mv->col + neighbors[j].col };
  
        if (is_mv_in(&x->mv_limits, &mv)) {
          unsigned int var =
              av1_get_mvpred_var(cm, x, &mv, &fcenter_mv, fn_ptr, 1);
          if (var < bestvar) {
            bestvar = var;
            best_site = j;
          }
        }
      }
  
      if (best_site == -1) {
        break;
      } else {
        x->second_best_mv.as_mv = *ref_mv;
        ref_mv->row += neighbors[best_site].row;
        ref_mv->col += neighbors[best_site].col;
      }
    }
  
    return bestvar;
  }
  
  static int full_pixel_diamond_var(const AV1_COMP *const cpi, MACROBLOCK *x,
                                    MV *mvp_full, int step_param,
                                    int further_steps, int do_refine,
                                    int *cost_list,
                                    const aom_variance_fn_ptr_t *fn_ptr,
                                    const MV *ref_mv,
                                    const search_site_config *cfg) {
    MV temp_mv;
    int thissme, n, num00 = 0;
    int bestsme = diamond_search_var(&cpi->common, x, cfg, mvp_full, &temp_mv,
                                     step_param, &n, fn_ptr, ref_mv);
    if (bestsme < INT_MAX)
      bestsme = av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr, 1);
    x->best_mv.as_mv = temp_mv;
  
    // If there won't be more n-step search, check to see if refining search is
    // needed.
    if (n > further_steps) do_refine = 0;
  
    while (n < further_steps) {
      ++n;
  
      if (num00) {
        num00--;
      } else {
        thissme = diamond_search_var(&cpi->common, x, cfg, mvp_full, &temp_mv,
                                     step_param + n, &num00, fn_ptr, ref_mv);
        if (thissme < INT_MAX)
          thissme =
              av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr, 1);
  
        // check to see if refining search is needed.
        if (num00 > further_steps - n) do_refine = 0;
  
        if (thissme < bestsme) {
          bestsme = thissme;
          x->best_mv.as_mv = temp_mv;
        }
      }
    }
  
    // final 1-away diamond refining search
    if (do_refine) {
      const int search_range = 8;
      MV best_mv = x->best_mv.as_mv;
      thissme = refining_search_var(&cpi->common, x, &best_mv, search_range,
                                    fn_ptr, ref_mv);
      if (thissme < INT_MAX)
        thissme =
            av1_get_mvpred_var(&cpi->common, x, &best_mv, ref_mv, fn_ptr, 1);
      if (thissme < bestsme) {
        bestsme = thissme;
        x->best_mv.as_mv = best_mv;
      }
    }
  
    // Return cost list.
    if (cost_list) {
      calc_int_cost_list(&cpi->common, x, ref_mv, x->errorperbit, fn_ptr,
                         &x->best_mv.as_mv, cost_list);
    }
    return bestsme;
  }
  
  static int full_pixel_exhaustive_var(const AV1_COMP *const cpi, MACROBLOCK *x,
                                       const MV *centre_mv_full, int *cost_list,
                                       const aom_variance_fn_ptr_t *fn_ptr,
                                       const MV *ref_mv, MV *dst_mv) {
    MV temp_mv = { centre_mv_full->row, centre_mv_full->col };
    MV f_ref_mv = { ref_mv->row >> 3, ref_mv->col >> 3 };
    int bestsme;
    int i;
    int interval = cpi->sf.mesh_patterns[0].interval;
    int range = cpi->sf.mesh_patterns[0].range;
    int baseline_interval_divisor;
  
    // Trap illegal values for interval and range for this function.
    if ((range < MIN_RANGE) || (range > MAX_RANGE) || (interval < MIN_INTERVAL) ||
        (interval > range))
      return INT_MAX;
  
    baseline_interval_divisor = range / interval;
  
    // Check size of proposed first range against magnitude of the centre
    // value used as a starting point.
    range = AOMMAX(range, (5 * AOMMAX(abs(temp_mv.row), abs(temp_mv.col))) / 4);
    range = AOMMIN(range, MAX_RANGE);
    interval = AOMMAX(interval, range / baseline_interval_divisor);
  
    // initial search
    bestsme = exhaustive_mesh_search_var(&cpi->common, x, &f_ref_mv, &temp_mv,
                                         range, interval, fn_ptr, &temp_mv);
  
    if ((interval > MIN_INTERVAL) && (range > MIN_RANGE)) {
      // Progressive searches with range and step size decreasing each time
      // till we reach a step size of 1. Then break out.
      for (i = 1; i < MAX_MESH_STEP; ++i) {
        // First pass with coarser step and longer range
        bestsme = exhaustive_mesh_search_var(
            &cpi->common, x, &f_ref_mv, &temp_mv, cpi->sf.mesh_patterns[i].range,
            cpi->sf.mesh_patterns[i].interval, fn_ptr, &temp_mv);
  
        if (cpi->sf.mesh_patterns[i].interval == 1) break;
      }
    }
  
    if (bestsme < INT_MAX)
      bestsme = av1_get_mvpred_var(&cpi->common, x, &temp_mv, ref_mv, fn_ptr, 1);
    *dst_mv = temp_mv;
  
    // Return cost list.
    if (cost_list) {
      calc_int_cost_list(
          // TODO(elliottk): check that errrorperbit is correct here
          &cpi->common, x, ref_mv, x->errorperbit, fn_ptr, dst_mv, cost_list);
    }
    return bestsme;
  }
  
  int av1_full_pixel_search_var(const AV1_COMP *cpi, MACROBLOCK *x,
                                BLOCK_SIZE bsize, MV *mvp_full, int step_param,
                                int *cost_list, const MV *ref_mv,
                                const search_site_config *cfg) {
    if (cost_list) {
      cost_list[0] = INT_MAX;
      cost_list[1] = INT_MAX;
      cost_list[2] = INT_MAX;
      cost_list[3] = INT_MAX;
      cost_list[4] = INT_MAX;
    }
  
    const SPEED_FEATURES *const sf = &cpi->sf;
    const aom_variance_fn_ptr_t *fn_ptr = &cpi->fn_ptr[bsize];
    int var = full_pixel_diamond_var(cpi, x, mvp_full, step_param,
                                     cfg->ss_count - 1 - step_param, 1, cost_list,
                                     fn_ptr, ref_mv, cfg);
  
    // Should we allow a follow on exhaustive search?
    bool run_exhaustive_search = false;
    int exhuastive_thr = sf->exhaustive_searches_thresh;
    exhuastive_thr >>= 10 - (mi_size_wide_log2[bsize] + mi_size_high_log2[bsize]);
  
    // Threshold variance for an exhaustive full search.
    run_exhaustive_search = var > exhuastive_thr;
  
    if (run_exhaustive_search) {
      int var_ex;
      MV tmp_mv_ex;
      var_ex = full_pixel_exhaustive_var(cpi, x, &x->best_mv.as_mv, cost_list,
                                         fn_ptr, ref_mv, &tmp_mv_ex);
      if (var_ex < var) {
        var = var_ex;
        x->best_mv.as_mv = tmp_mv_ex;
      }
    }
    return var;
  }
  