/*

 * Copyright (c) 2020, 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 "av1/common/pred_common.h"

#include "av1/encoder/interp_search.h"

#include "av1/encoder/model_rd.h"

#include "av1/encoder/rdopt_utils.h"

#include "av1/encoder/reconinter_enc.h"

// return mv_diff

static inline int is_interp_filter_good_match(

    const INTERPOLATION_FILTER_STATS *st, MB_MODE_INFO *const mi,

    int skip_level) {

  const int is_comp = has_second_ref(mi);

  int i;

  for (i = 0; i < 1 + is_comp; ++i) {

    if (st->ref_frames[i] != mi->ref_frame[i]) return INT_MAX;

  }

  if (skip_level == 1 && is_comp) {

    if (st->comp_type != mi->interinter_comp.type) return INT_MAX;

    if (st->compound_idx != mi->compound_idx) return INT_MAX;

  }

  int mv_diff = 0;

  for (i = 0; i < 1 + is_comp; ++i) {

    mv_diff += abs(st->mv[i].as_mv.row - mi->mv[i].as_mv.row) +

               abs(st->mv[i].as_mv.col - mi->mv[i].as_mv.col);

  }

  return mv_diff;

}

static inline int save_interp_filter_search_stat(

    MB_MODE_INFO *const mbmi, int64_t rd, unsigned int pred_sse,

    INTERPOLATION_FILTER_STATS *interp_filter_stats,

    int interp_filter_stats_idx) {

  if (interp_filter_stats_idx < MAX_INTERP_FILTER_STATS) {

    INTERPOLATION_FILTER_STATS stat = { mbmi->interp_filters,

                                        { mbmi->mv[0], mbmi->mv[1] },

                                        { mbmi->ref_frame[0],

                                          mbmi->ref_frame[1] },

                                        mbmi->interinter_comp.type,

                                        mbmi->compound_idx,

                                        rd,

                                        pred_sse };

    interp_filter_stats[interp_filter_stats_idx] = stat;

    interp_filter_stats_idx++;

  }

  return interp_filter_stats_idx;

}

static inline int find_interp_filter_in_stats(

    MB_MODE_INFO *const mbmi, INTERPOLATION_FILTER_STATS *interp_filter_stats,

    int interp_filter_stats_idx, int skip_level) {

  // [skip_levels][single or comp]

  const int thr[2][2] = { { 0, 0 }, { 3, 7 } };

  const int is_comp = has_second_ref(mbmi);

  // Find good enough match.

  // TODO(yunqing): Separate single-ref mode and comp mode stats for fast

  // search.

  int best = INT_MAX;

  int match = -1;

  for (int j = 0; j < interp_filter_stats_idx; ++j) {

    const INTERPOLATION_FILTER_STATS *st = &interp_filter_stats[j];

    const int mv_diff = is_interp_filter_good_match(st, mbmi, skip_level);

    // Exact match is found.

    if (mv_diff == 0) {

      match = j;

      break;

    } else if (mv_diff < best && mv_diff <= thr[skip_level - 1][is_comp]) {

      best = mv_diff;

      match = j;

    }

  }

  if (match != -1) {

    mbmi->interp_filters = interp_filter_stats[match].filters;

    return match;

  }

  return -1;  // no match result found

}

static int find_interp_filter_match(

    MB_MODE_INFO *const mbmi, const AV1_COMP *const cpi,

    const InterpFilter assign_filter, const int need_search,

    INTERPOLATION_FILTER_STATS *interp_filter_stats,

    int interp_filter_stats_idx) {

  int match_found_idx = -1;

  if (cpi->sf.interp_sf.use_interp_filter && need_search)

    match_found_idx = find_interp_filter_in_stats(

        mbmi, interp_filter_stats, interp_filter_stats_idx,

        cpi->sf.interp_sf.use_interp_filter);

  if (!need_search || match_found_idx == -1)

    set_default_interp_filters(mbmi, assign_filter);

  return match_found_idx;

}

static inline int get_switchable_rate(MACROBLOCK *const x,

                                      const int_interpfilters filters,

                                      const int ctx[2], int dual_filter) {

  const InterpFilter filter0 = filters.as_filters.y_filter;

  int inter_filter_cost =

      x->mode_costs.switchable_interp_costs[ctx[0]][filter0];

  if (dual_filter) {

    const InterpFilter filter1 = filters.as_filters.x_filter;

    inter_filter_cost += x->mode_costs.switchable_interp_costs[ctx[1]][filter1];

  }

  return SWITCHABLE_INTERP_RATE_FACTOR * inter_filter_cost;

}

// Build inter predictor and calculate model rd

// for a given plane.

static inline void interp_model_rd_eval(

    MACROBLOCK *const x, const AV1_COMP *const cpi, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int plane_from, int plane_to,

    RD_STATS *rd_stats, int is_skip_build_pred) {

  const AV1_COMMON *cm = &cpi->common;

  MACROBLOCKD *const xd = &x->e_mbd;

  RD_STATS tmp_rd_stats;

  av1_init_rd_stats(&tmp_rd_stats);

  // Skip inter predictor if the predictor is already available.

  if (!is_skip_build_pred) {

    const int mi_row = xd->mi_row;

    const int mi_col = xd->mi_col;

    av1_enc_build_inter_predictor(cm, xd, mi_row, mi_col, orig_dst, bsize,

                                  plane_from, plane_to);

  }

  model_rd_sb_fn[cpi->sf.rt_sf.use_simple_rd_model

                     ? MODELRD_LEGACY

                     : MODELRD_TYPE_INTERP_FILTER](

      cpi, bsize, x, xd, plane_from, plane_to, &tmp_rd_stats.rate,

      &tmp_rd_stats.dist, &tmp_rd_stats.skip_txfm, &tmp_rd_stats.sse, NULL,

      NULL, NULL);

  av1_merge_rd_stats(rd_stats, &tmp_rd_stats);

}

// calculate the rdcost of given interpolation_filter

static inline int64_t interpolation_filter_rd(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int64_t *const rd,

    RD_STATS *rd_stats_luma, RD_STATS *rd_stats, int *const switchable_rate,

    const BUFFER_SET *dst_bufs[2], int filter_idx, const int switchable_ctx[2],

    const int skip_pred) {

  const AV1_COMMON *cm = &cpi->common;

  const InterpSearchFlags *interp_search_flags = &cpi->interp_search_flags;

  const int num_planes = av1_num_planes(cm);

  MACROBLOCKD *const xd = &x->e_mbd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  RD_STATS this_rd_stats_luma, this_rd_stats;

  // Initialize rd_stats structures to default values.

  av1_init_rd_stats(&this_rd_stats_luma);

  this_rd_stats = *rd_stats_luma;

  const int_interpfilters last_best = mbmi->interp_filters;

  mbmi->interp_filters = filter_sets[filter_idx];

  const int tmp_rs =

      get_switchable_rate(x, mbmi->interp_filters, switchable_ctx,

                          cm->seq_params->enable_dual_filter);

  int64_t min_rd = RDCOST(x->rdmult, tmp_rs, 0);

  if (min_rd > *rd) {

    mbmi->interp_filters = last_best;

    return 0;

  }

  (void)tile_data;

  assert(skip_pred != 2);

  assert((rd_stats_luma->rate >= 0) && (rd_stats->rate >= 0));

  assert((rd_stats_luma->dist >= 0) && (rd_stats->dist >= 0));

  assert((rd_stats_luma->sse >= 0) && (rd_stats->sse >= 0));

  assert((rd_stats_luma->skip_txfm == 0) || (rd_stats_luma->skip_txfm == 1));

  assert((rd_stats->skip_txfm == 0) || (rd_stats->skip_txfm == 1));

  assert((skip_pred >= 0) &&

         (skip_pred <= interp_search_flags->default_interp_skip_flags));

  // When skip_txfm pred is equal to default_interp_skip_flags,

  // skip both luma and chroma MC.

  // For mono-chrome images:

  // num_planes = 1 and cpi->default_interp_skip_flags = 1,

  // skip_pred = 1: skip both luma and chroma

  // skip_pred = 0: Evaluate luma and as num_planes=1,

  // skip chroma evaluation

  int tmp_skip_pred =

      (skip_pred == interp_search_flags->default_interp_skip_flags)

          ? INTERP_SKIP_LUMA_SKIP_CHROMA

          : skip_pred;

  switch (tmp_skip_pred) {

    case INTERP_EVAL_LUMA_EVAL_CHROMA:

      // skip_pred = 0: Evaluate both luma and chroma.

      // Luma MC

      interp_model_rd_eval(x, cpi, bsize, orig_dst, AOM_PLANE_Y, AOM_PLANE_Y,

                           &this_rd_stats_luma, 0);

      this_rd_stats = this_rd_stats_luma;

#if CONFIG_COLLECT_RD_STATS == 3

      RD_STATS rd_stats_y;

      av1_pick_recursive_tx_size_type_yrd(cpi, x, &rd_stats_y, bsize,

                                          INT64_MAX);

      PrintPredictionUnitStats(cpi, tile_data, x, &rd_stats_y, bsize);

#endif  // CONFIG_COLLECT_RD_STATS == 3

      AOM_FALLTHROUGH_INTENDED;

    case INTERP_SKIP_LUMA_EVAL_CHROMA:

      // skip_pred = 1: skip luma evaluation (retain previous best luma stats)

      // and do chroma evaluation.

      for (int plane = 1; plane < num_planes; ++plane) {

        int64_t tmp_rd =

            RDCOST(x->rdmult, tmp_rs + this_rd_stats.rate, this_rd_stats.dist);

        if (tmp_rd >= *rd) {

          mbmi->interp_filters = last_best;

          return 0;

        }

        interp_model_rd_eval(x, cpi, bsize, orig_dst, plane, plane,

                             &this_rd_stats, 0);

      }

      break;

    case INTERP_SKIP_LUMA_SKIP_CHROMA:

      // both luma and chroma evaluation is skipped

      this_rd_stats = *rd_stats;

      break;

    case INTERP_EVAL_INVALID:

    default: assert(0); return 0;

  }

  int64_t tmp_rd =

      RDCOST(x->rdmult, tmp_rs + this_rd_stats.rate, this_rd_stats.dist);

  if (tmp_rd < *rd) {

    *rd = tmp_rd;

    *switchable_rate = tmp_rs;

    if (skip_pred != interp_search_flags->default_interp_skip_flags) {

      if (skip_pred == INTERP_EVAL_LUMA_EVAL_CHROMA) {

        // Overwrite the data as current filter is the best one

        *rd_stats_luma = this_rd_stats_luma;

        *rd_stats = this_rd_stats;

        // As luma MC data is computed, no need to recompute after the search

        x->recalc_luma_mc_data = 0;

      } else if (skip_pred == INTERP_SKIP_LUMA_EVAL_CHROMA) {

        // As luma MC data is not computed, update of luma data can be skipped

        *rd_stats = this_rd_stats;

        // As luma MC data is not recomputed and current filter is the best,

        // indicate the possibility of recomputing MC data

        // If current buffer contains valid MC data, toggle to indicate that

        // luma MC data needs to be recomputed

        x->recalc_luma_mc_data ^= 1;

      }

      swap_dst_buf(xd, dst_bufs, num_planes);

    }

    return 1;

  }

  mbmi->interp_filters = last_best;

  return 0;

}

static inline INTERP_PRED_TYPE is_pred_filter_search_allowed(

    const AV1_COMP *const cpi, MACROBLOCKD *xd, BLOCK_SIZE bsize,

    int_interpfilters *af, int_interpfilters *lf) {

  const AV1_COMMON *cm = &cpi->common;

  const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;

  const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;

  const int bsl = mi_size_wide_log2[bsize];

  int is_horiz_eq = 0, is_vert_eq = 0;

  if (above_mbmi && is_inter_block(above_mbmi))

    *af = above_mbmi->interp_filters;

  if (left_mbmi && is_inter_block(left_mbmi)) *lf = left_mbmi->interp_filters;

  if (af->as_filters.x_filter != INTERP_INVALID)

    is_horiz_eq = af->as_filters.x_filter == lf->as_filters.x_filter;

  if (af->as_filters.y_filter != INTERP_INVALID)

    is_vert_eq = af->as_filters.y_filter == lf->as_filters.y_filter;

  INTERP_PRED_TYPE pred_filter_type = (is_vert_eq << 1) + is_horiz_eq;

  const int mi_row = xd->mi_row;

  const int mi_col = xd->mi_col;

  int pred_filter_enable =

      cpi->sf.interp_sf.cb_pred_filter_search

          ? (((mi_row + mi_col) >> bsl) +

             get_chessboard_index(cm->current_frame.frame_number)) &

                0x1

          : 0;

  pred_filter_enable &= is_horiz_eq || is_vert_eq;

  // pred_filter_search = 0: pred_filter is disabled

  // pred_filter_search = 1: pred_filter is enabled and only horz pred matching

  // pred_filter_search = 2: pred_filter is enabled and only vert pred matching

  // pred_filter_search = 3: pred_filter is enabled and

  //                         both vert, horz pred matching

  return pred_filter_enable * pred_filter_type;

}

static DUAL_FILTER_TYPE find_best_interp_rd_facade(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int64_t *const rd, RD_STATS *rd_stats_y,

    RD_STATS *rd_stats, int *const switchable_rate,

    const BUFFER_SET *dst_bufs[2], const int switchable_ctx[2],

    const int skip_pred, uint16_t allow_interp_mask, int is_w4_or_h4) {

  int tmp_skip_pred = skip_pred;

  DUAL_FILTER_TYPE best_filt_type = REG_REG;

  // If no filter are set to be evaluated, return from function

  if (allow_interp_mask == 0x0) return best_filt_type;

  // For block width or height is 4, skip the pred evaluation of SHARP_SHARP

  tmp_skip_pred = is_w4_or_h4

                      ? cpi->interp_search_flags.default_interp_skip_flags

                      : skip_pred;

  // Loop over the all filter types and evaluate for only allowed filter types

  for (int filt_type = SHARP_SHARP; filt_type >= REG_REG; --filt_type) {

    const int is_filter_allowed =

        get_interp_filter_allowed_mask(allow_interp_mask, filt_type);

    if (is_filter_allowed)

      if (interpolation_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                                  rd_stats_y, rd_stats, switchable_rate,

                                  dst_bufs, filt_type, switchable_ctx,

                                  tmp_skip_pred))

        best_filt_type = filt_type;

    tmp_skip_pred = skip_pred;

  }

  return best_filt_type;

}

static inline void pred_dual_interp_filter_rd(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int64_t *const rd, RD_STATS *rd_stats_y,

    RD_STATS *rd_stats, int *const switchable_rate,

    const BUFFER_SET *dst_bufs[2], const int switchable_ctx[2],

    const int skip_pred, INTERP_PRED_TYPE pred_filt_type, int_interpfilters *af,

    int_interpfilters *lf) {

  (void)lf;

  assert(pred_filt_type > INTERP_HORZ_NEQ_VERT_NEQ);

  assert(pred_filt_type < INTERP_PRED_TYPE_ALL);

  uint16_t allowed_interp_mask = 0;

  if (pred_filt_type == INTERP_HORZ_EQ_VERT_NEQ) {

    // pred_filter_search = 1: Only horizontal filter is matching

    allowed_interp_mask =

        av1_interp_dual_filt_mask[pred_filt_type - 1][af->as_filters.x_filter];

  } else if (pred_filt_type == INTERP_HORZ_NEQ_VERT_EQ) {

    // pred_filter_search = 2: Only vertical filter is matching

    allowed_interp_mask =

        av1_interp_dual_filt_mask[pred_filt_type - 1][af->as_filters.y_filter];

  } else {

    // pred_filter_search = 3: Both horizontal and vertical filter are matching

    int filt_type =

        af->as_filters.x_filter + af->as_filters.y_filter * SWITCHABLE_FILTERS;

    set_interp_filter_allowed_mask(&allowed_interp_mask, filt_type);

  }

  // REG_REG is already been evaluated in the beginning

  reset_interp_filter_allowed_mask(&allowed_interp_mask, REG_REG);

  find_best_interp_rd_facade(x, cpi, tile_data, bsize, orig_dst, rd, rd_stats_y,

                             rd_stats, switchable_rate, dst_bufs,

                             switchable_ctx, skip_pred, allowed_interp_mask, 0);

}

// Evaluate dual filter type

// a) Using above, left block interp filter

// b) Find the best horizontal filter and

//    then evaluate corresponding vertical filters.

static inline void fast_dual_interp_filter_rd(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int64_t *const rd, RD_STATS *rd_stats_y,

    RD_STATS *rd_stats, int *const switchable_rate,

    const BUFFER_SET *dst_bufs[2], const int switchable_ctx[2],

    const int skip_hor, const int skip_ver) {

  const InterpSearchFlags *interp_search_flags = &cpi->interp_search_flags;

  MACROBLOCKD *const xd = &x->e_mbd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  INTERP_PRED_TYPE pred_filter_type = INTERP_HORZ_NEQ_VERT_NEQ;

  int_interpfilters af = av1_broadcast_interp_filter(INTERP_INVALID);

  int_interpfilters lf = af;

  if (!have_newmv_in_inter_mode(mbmi->mode)) {

    pred_filter_type = is_pred_filter_search_allowed(cpi, xd, bsize, &af, &lf);

  }

  if (pred_filter_type) {

    pred_dual_interp_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                               rd_stats_y, rd_stats, switchable_rate, dst_bufs,

                               switchable_ctx, (skip_hor & skip_ver),

                               pred_filter_type, &af, &lf);

  } else {

    const int bw = block_size_wide[bsize];

    const int bh = block_size_high[bsize];

    int best_dual_mode = 0;

    int skip_pred =

        bw <= 4 ? interp_search_flags->default_interp_skip_flags : skip_hor;

    // TODO(any): Make use of find_best_interp_rd_facade()

    // if speed impact is negligible

    for (int i = (SWITCHABLE_FILTERS - 1); i >= 1; --i) {

      if (interpolation_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                                  rd_stats_y, rd_stats, switchable_rate,

                                  dst_bufs, i, switchable_ctx, skip_pred)) {

        best_dual_mode = i;

      }

      skip_pred = skip_hor;

    }

    // From best of horizontal EIGHTTAP_REGULAR modes, check vertical modes

    skip_pred =

        bh <= 4 ? interp_search_flags->default_interp_skip_flags : skip_ver;

    for (int i = (best_dual_mode + (SWITCHABLE_FILTERS * 2));

         i >= (best_dual_mode + SWITCHABLE_FILTERS); i -= SWITCHABLE_FILTERS) {

      interpolation_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                              rd_stats_y, rd_stats, switchable_rate, dst_bufs,

                              i, switchable_ctx, skip_pred);

      skip_pred = skip_ver;

    }

  }

}

// Find the best interp filter if dual_interp_filter = 0

static inline void find_best_non_dual_interp_filter(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const orig_dst, int64_t *const rd, RD_STATS *rd_stats_y,

    RD_STATS *rd_stats, int *const switchable_rate,

    const BUFFER_SET *dst_bufs[2], const int switchable_ctx[2],

    const int skip_ver, const int skip_hor) {

  const InterpSearchFlags *interp_search_flags = &cpi->interp_search_flags;

  int8_t i;

  MACROBLOCKD *const xd = &x->e_mbd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  uint16_t interp_filter_search_mask =

      interp_search_flags->interp_filter_search_mask;

  if (cpi->sf.interp_sf.adaptive_interp_filter_search == 2) {

    const FRAME_UPDATE_TYPE update_type =

        get_frame_update_type(&cpi->ppi->gf_group, cpi->gf_frame_index);

    const int ctx0 = av1_get_pred_context_switchable_interp(xd, 0);

    const int ctx1 = av1_get_pred_context_switchable_interp(xd, 1);

    int use_actual_frame_probs = 1;

    const int *switchable_interp_p0;

    const int *switchable_interp_p1;

#if CONFIG_FPMT_TEST

    use_actual_frame_probs =

        (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE) ? 0 : 1;

    if (!use_actual_frame_probs) {

      switchable_interp_p0 = (int *)cpi->ppi->temp_frame_probs

                                 .switchable_interp_probs[update_type][ctx0];

      switchable_interp_p1 = (int *)cpi->ppi->temp_frame_probs

                                 .switchable_interp_probs[update_type][ctx1];

    }

#endif

    if (use_actual_frame_probs) {

      switchable_interp_p0 =

          cpi->ppi->frame_probs.switchable_interp_probs[update_type][ctx0];

      switchable_interp_p1 =

          cpi->ppi->frame_probs.switchable_interp_probs[update_type][ctx1];

    }

    static const int thr[7] = { 0, 8, 8, 8, 8, 0, 8 };

    const int thresh = thr[update_type];

    for (i = 0; i < SWITCHABLE_FILTERS; i++) {

      // For non-dual case, the 2 dir's prob should be identical.

      assert(switchable_interp_p0[i] == switchable_interp_p1[i]);

      if (switchable_interp_p0[i] < thresh &&

          switchable_interp_p1[i] < thresh) {

        DUAL_FILTER_TYPE filt_type = i + SWITCHABLE_FILTERS * i;

        reset_interp_filter_allowed_mask(&interp_filter_search_mask, filt_type);

      }

    }

  }

  // Regular filter evaluation should have been done and hence the same should

  // be the winner

  assert(x->e_mbd.mi[0]->interp_filters.as_int == filter_sets[0].as_int);

  if ((skip_hor & skip_ver) != interp_search_flags->default_interp_skip_flags) {

    INTERP_PRED_TYPE pred_filter_type = INTERP_HORZ_NEQ_VERT_NEQ;

    int_interpfilters af = av1_broadcast_interp_filter(INTERP_INVALID);

    int_interpfilters lf = af;

    pred_filter_type = is_pred_filter_search_allowed(cpi, xd, bsize, &af, &lf);

    if (pred_filter_type) {

      assert(af.as_filters.x_filter != INTERP_INVALID);

      int filter_idx = SWITCHABLE * af.as_filters.x_filter;

      // This assert tells that (filter_x == filter_y) for non-dual filter case

      assert(filter_sets[filter_idx].as_filters.x_filter ==

             filter_sets[filter_idx].as_filters.y_filter);

      if (cpi->sf.interp_sf.adaptive_interp_filter_search &&

          !(get_interp_filter_allowed_mask(interp_filter_search_mask,

                                           filter_idx))) {

        return;

      }

      if (filter_idx) {

        interpolation_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                                rd_stats_y, rd_stats, switchable_rate, dst_bufs,

                                filter_idx, switchable_ctx,

                                (skip_hor & skip_ver));

      }

      return;

    }

  }

  // Reuse regular filter's modeled rd data for sharp filter for following

  // cases

  // 1) When bsize is 4x4

  // 2) When block width is 4 (i.e. 4x8/4x16 blocks) and MV in vertical

  // direction is full-pel

  // 3) When block height is 4 (i.e. 8x4/16x4 blocks) and MV in horizontal

  // direction is full-pel

  // TODO(any): Optimize cases 2 and 3 further if luma MV in relavant direction

  // alone is full-pel

  if ((bsize == BLOCK_4X4) ||

      (block_size_wide[bsize] == 4 &&

       skip_ver == interp_search_flags->default_interp_skip_flags) ||

      (block_size_high[bsize] == 4 &&

       skip_hor == interp_search_flags->default_interp_skip_flags)) {

    int skip_pred = skip_hor & skip_ver;

    uint16_t allowed_interp_mask = 0;

    // REG_REG filter type is evaluated beforehand, hence skip it

    set_interp_filter_allowed_mask(&allowed_interp_mask, SHARP_SHARP);

    set_interp_filter_allowed_mask(&allowed_interp_mask, SMOOTH_SMOOTH);

    if (cpi->sf.interp_sf.adaptive_interp_filter_search)

      allowed_interp_mask &= interp_filter_search_mask;

    find_best_interp_rd_facade(x, cpi, tile_data, bsize, orig_dst, rd,

                               rd_stats_y, rd_stats, switchable_rate, dst_bufs,

                               switchable_ctx, skip_pred, allowed_interp_mask,

                               1);

  } else {

    int skip_pred = (skip_hor & skip_ver);

    for (i = (SWITCHABLE_FILTERS + 1); i < DUAL_FILTER_SET_SIZE;

         i += (SWITCHABLE_FILTERS + 1)) {

      // This assert tells that (filter_x == filter_y) for non-dual filter case

      assert(filter_sets[i].as_filters.x_filter ==

             filter_sets[i].as_filters.y_filter);

      if (cpi->sf.interp_sf.adaptive_interp_filter_search &&

          !(get_interp_filter_allowed_mask(interp_filter_search_mask, i))) {

        continue;

      }

      interpolation_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                              rd_stats_y, rd_stats, switchable_rate, dst_bufs,

                              i, switchable_ctx, skip_pred);

      // In first iteration, smooth filter is evaluated. If smooth filter

      // (which is less sharper) is the winner among regular and smooth filters,

      // sharp filter evaluation is skipped

      // TODO(any): Refine this gating based on modelled rd only (i.e., by not

      // accounting switchable filter rate)

      if (cpi->sf.interp_sf.skip_sharp_interp_filter_search &&

          skip_pred != interp_search_flags->default_interp_skip_flags) {

        if (mbmi->interp_filters.as_int == filter_sets[SMOOTH_SMOOTH].as_int)

          break;

      }

    }

  }

}

static inline void calc_interp_skip_pred_flag(MACROBLOCK *const x,

                                              const AV1_COMP *const cpi,

                                              int *skip_hor, int *skip_ver) {

  const AV1_COMMON *cm = &cpi->common;

  MACROBLOCKD *const xd = &x->e_mbd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  const int num_planes = av1_num_planes(cm);

  const int is_compound = has_second_ref(mbmi);

  assert(is_intrabc_block(mbmi) == 0);

  for (int ref = 0; ref < 1 + is_compound; ++ref) {

    const struct scale_factors *const sf =

        get_ref_scale_factors_const(cm, mbmi->ref_frame[ref]);

    // TODO(any): Refine skip flag calculation considering scaling

    if (av1_is_scaled(sf)) {

      *skip_hor = 0;

      *skip_ver = 0;

      break;

    }

    const MV mv = mbmi->mv[ref].as_mv;

    int skip_hor_plane = 0;

    int skip_ver_plane = 0;

    for (int plane_idx = 0; plane_idx < AOMMAX(1, (num_planes - 1));

         ++plane_idx) {

      struct macroblockd_plane *const pd = &xd->plane[plane_idx];

      const int bw = pd->width;

      const int bh = pd->height;

      const MV mv_q4 = clamp_mv_to_umv_border_sb(

          xd, &mv, bw, bh, pd->subsampling_x, pd->subsampling_y);

      const int sub_x = (mv_q4.col & SUBPEL_MASK) << SCALE_EXTRA_BITS;

      const int sub_y = (mv_q4.row & SUBPEL_MASK) << SCALE_EXTRA_BITS;

      skip_hor_plane |= ((sub_x == 0) << plane_idx);

      skip_ver_plane |= ((sub_y == 0) << plane_idx);

    }

    *skip_hor &= skip_hor_plane;

    *skip_ver &= skip_ver_plane;

    // It is not valid that "luma MV is sub-pel, whereas chroma MV is not"

    assert(*skip_hor != 2);

    assert(*skip_ver != 2);

  }

  // When compond prediction type is compound segment wedge, luma MC and chroma

  // MC need to go hand in hand as mask generated during luma MC is reuired for

  // chroma MC. If skip_hor = 0 and skip_ver = 1, mask used for chroma MC during

  // vertical filter decision may be incorrect as temporary MC evaluation

  // overwrites the mask. Make skip_ver as 0 for this case so that mask is

  // populated during luma MC

  if (is_compound && mbmi->compound_idx == 1 &&

      mbmi->interinter_comp.type == COMPOUND_DIFFWTD) {

    assert(mbmi->comp_group_idx == 1);

    if (*skip_hor == 0 && *skip_ver == 1) *skip_ver = 0;

  }

}

/*!\brief AV1 interpolation filter search

 *

 * \ingroup inter_mode_search

 *

 * \param[in]     cpi               Top-level encoder structure.

 * \param[in]     tile_data         Pointer to struct holding adaptive

 *                                  data/contexts/models for the tile during

 *                                  encoding.

 * \param[in]     x                 Pointer to struc holding all the data for

 *                                  the current macroblock.

 * \param[in]     bsize             Current block size.

 * \param[in]     tmp_dst           A temporary prediction buffer to hold a

 *                                  computed prediction.

 * \param[in,out] orig_dst          A prediction buffer to hold a computed

 *                                  prediction. This will eventually hold the

 *                                  final prediction, and the tmp_dst info will

 *                                  be copied here.

 * \param[in,out] rd                The RD cost associated with the selected

 *                                  interpolation filter parameters.

 * \param[in,out] switchable_rate   The rate associated with using a SWITCHABLE

 *                                  filter mode.

 * \param[in,out] skip_build_pred   Indicates whether or not to build the inter

 *                                  predictor. If this is 0, the inter predictor

 *                                  has already been built and thus we can avoid

 *                                  repeating computation.

 * \param[in]     args              HandleInterModeArgs struct holding

 *                                  miscellaneous arguments for inter mode

 *                                  search. See the documentation for this

 *                                  struct for a description of each member.

 * \param[in]     ref_best_rd       Best RD found so far for this block.

 *                                  It is used for early termination of this

 *                                  search if the RD exceeds this value.

 *

 * \return Returns INT64_MAX if the filter parameters are invalid and the

 * current motion mode being tested should be skipped. It returns 0 if the

 * parameter search is a success.

 */

int64_t av1_interpolation_filter_search(

    MACROBLOCK *const x, const AV1_COMP *const cpi,

    const TileDataEnc *tile_data, BLOCK_SIZE bsize,

    const BUFFER_SET *const tmp_dst, const BUFFER_SET *const orig_dst,

    int64_t *const rd, int *const switchable_rate, int *skip_build_pred,

    HandleInterModeArgs *args, int64_t ref_best_rd) {

  const AV1_COMMON *cm = &cpi->common;

  const InterpSearchFlags *interp_search_flags = &cpi->interp_search_flags;

  const int num_planes = av1_num_planes(cm);

  MACROBLOCKD *const xd = &x->e_mbd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  const int need_search = av1_is_interp_needed(xd);

  const int ref_frame = xd->mi[0]->ref_frame[0];

  RD_STATS rd_stats_luma, rd_stats;

  // Initialization of rd_stats structures with default values

  av1_init_rd_stats(&rd_stats_luma);

  av1_init_rd_stats(&rd_stats);

  int match_found_idx = -1;

  const InterpFilter assign_filter = cm->features.interp_filter;

  match_found_idx = find_interp_filter_match(

      mbmi, cpi, assign_filter, need_search, args->interp_filter_stats,

      args->interp_filter_stats_idx);

  if (match_found_idx != -1) {

    *rd = args->interp_filter_stats[match_found_idx].rd;

    x->pred_sse[ref_frame] =

        args->interp_filter_stats[match_found_idx].pred_sse;

    *skip_build_pred = 0;

    return 0;

  }

  int switchable_ctx[2];

  switchable_ctx[0] = av1_get_pred_context_switchable_interp(xd, 0);

  switchable_ctx[1] = av1_get_pred_context_switchable_interp(xd, 1);

  *switchable_rate =

      get_switchable_rate(x, mbmi->interp_filters, switchable_ctx,

                          cm->seq_params->enable_dual_filter);

  // Do MC evaluation for default filter_type.

  // Luma MC

  interp_model_rd_eval(x, cpi, bsize, orig_dst, AOM_PLANE_Y, AOM_PLANE_Y,

                       &rd_stats_luma, *skip_build_pred);

#if CONFIG_COLLECT_RD_STATS == 3

  RD_STATS rd_stats_y;

  av1_pick_recursive_tx_size_type_yrd(cpi, x, &rd_stats_y, bsize, INT64_MAX);

  PrintPredictionUnitStats(cpi, tile_data, x, &rd_stats_y, bsize);

#endif  // CONFIG_COLLECT_RD_STATS == 3

  // Chroma MC

  if (num_planes > 1) {

    interp_model_rd_eval(x, cpi, bsize, orig_dst, AOM_PLANE_U, AOM_PLANE_V,

                         &rd_stats, *skip_build_pred);

  }

  *skip_build_pred = 1;

  av1_merge_rd_stats(&rd_stats, &rd_stats_luma);

  assert(rd_stats.rate >= 0);

  *rd = RDCOST(x->rdmult, *switchable_rate + rd_stats.rate, rd_stats.dist);

  x->pred_sse[ref_frame] = (unsigned int)(rd_stats_luma.sse >> 4);

  if (assign_filter != SWITCHABLE || match_found_idx != -1) {

    return 0;

  }

  if (!need_search) {

    int_interpfilters filters = av1_broadcast_interp_filter(EIGHTTAP_REGULAR);

    assert(mbmi->interp_filters.as_int == filters.as_int);

    (void)filters;

    return 0;

  }

  if (args->modelled_rd != NULL) {

    if (has_second_ref(mbmi)) {

      const int ref_mv_idx = mbmi->ref_mv_idx;

      MV_REFERENCE_FRAME *refs = mbmi->ref_frame;

      const int mode0 = compound_ref0_mode(mbmi->mode);

      const int mode1 = compound_ref1_mode(mbmi->mode);

      const int64_t mrd = AOMMIN(args->modelled_rd[mode0][ref_mv_idx][refs[0]],

                                 args->modelled_rd[mode1][ref_mv_idx][refs[1]]);

      if ((*rd >> 1) > mrd && ref_best_rd < INT64_MAX) {

        return INT64_MAX;

      }

    }

  }

  x->recalc_luma_mc_data = 0;

  // skip_flag=xx (in binary form)

  // Setting 0th flag corresonds to skipping luma MC and setting 1st bt

  // corresponds to skipping chroma MC  skip_flag=0 corresponds to "Don't skip

  // luma and chroma MC"  Skip flag=1 corresponds to "Skip Luma MC only"

  // Skip_flag=2 is not a valid case

  // skip_flag=3 corresponds to "Skip both luma and chroma MC"

  int skip_hor = interp_search_flags->default_interp_skip_flags;

  int skip_ver = interp_search_flags->default_interp_skip_flags;

  calc_interp_skip_pred_flag(x, cpi, &skip_hor, &skip_ver);

  // do interp_filter search

  restore_dst_buf(xd, *tmp_dst, num_planes);

  const BUFFER_SET *dst_bufs[2] = { tmp_dst, orig_dst };

  // Evaluate dual interp filters

  if (cm->seq_params->enable_dual_filter) {

    if (cpi->sf.interp_sf.use_fast_interpolation_filter_search) {

      fast_dual_interp_filter_rd(x, cpi, tile_data, bsize, orig_dst, rd,

                                 &rd_stats_luma, &rd_stats, switchable_rate,

                                 dst_bufs, switchable_ctx, skip_hor, skip_ver);

    } else {

      // Use full interpolation filter search

      uint16_t allowed_interp_mask = ALLOW_ALL_INTERP_FILT_MASK;

      // REG_REG filter type is evaluated beforehand, so loop is repeated over

      // REG_SMOOTH to SHARP_SHARP for full interpolation filter search

      reset_interp_filter_allowed_mask(&allowed_interp_mask, REG_REG);

      find_best_interp_rd_facade(x, cpi, tile_data, bsize, orig_dst, rd,

                                 &rd_stats_luma, &rd_stats, switchable_rate,

                                 dst_bufs, switchable_ctx,

                                 (skip_hor & skip_ver), allowed_interp_mask, 0);

    }

  } else {

    // Evaluate non-dual interp filters

    find_best_non_dual_interp_filter(

        x, cpi, tile_data, bsize, orig_dst, rd, &rd_stats_luma, &rd_stats,

        switchable_rate, dst_bufs, switchable_ctx, skip_ver, skip_hor);

  }

  swap_dst_buf(xd, dst_bufs, num_planes);

  // Recompute final MC data if required

  if (x->recalc_luma_mc_data == 1) {

    // Recomputing final luma MC data is required only if the same was skipped

    // in either of the directions  Condition below is necessary, but not

    // sufficient

    assert((skip_hor == 1) || (skip_ver == 1));

    const int mi_row = xd->mi_row;

    const int mi_col = xd->mi_col;

    av1_enc_build_inter_predictor(cm, xd, mi_row, mi_col, orig_dst, bsize,

                                  AOM_PLANE_Y, AOM_PLANE_Y);

  }

  x->pred_sse[ref_frame] = (unsigned int)(rd_stats_luma.sse >> 4);

  // save search results

  if (cpi->sf.interp_sf.use_interp_filter) {

    assert(match_found_idx == -1);

    args->interp_filter_stats_idx = save_interp_filter_search_stat(

        mbmi, *rd, x->pred_sse[ref_frame], args->interp_filter_stats,

        args->interp_filter_stats_idx);

  }

  return 0;

}