/*

 * 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 "av1/common/pred_common.h"

#include "av1/common/seg_common.h"

#include "av1/encoder/aq_cyclicrefresh.h"

#include "av1/encoder/encoder_utils.h"

#include "av1/encoder/ratectrl.h"

#include "av1/encoder/segmentation.h"

#include "av1/encoder/tokenize.h"

#include "aom_dsp/aom_dsp_common.h"

CYCLIC_REFRESH *av1_cyclic_refresh_alloc(int mi_rows, int mi_cols) {

  CYCLIC_REFRESH *const cr = aom_calloc(1, sizeof(*cr));

  if (cr == NULL) return NULL;

  cr->map = aom_calloc(mi_rows * mi_cols, sizeof(*cr->map));

  cr->counter_encode_maxq_scene_change = 0;

  cr->percent_refresh_adjustment = 5;

  cr->rate_ratio_qdelta_adjustment = 0.25;

  if (cr->map == NULL) {

    av1_cyclic_refresh_free(cr);

    return NULL;

  }

  return cr;

}

void av1_cyclic_refresh_free(CYCLIC_REFRESH *cr) {

  if (cr != NULL) {

    aom_free(cr->map);

    aom_free(cr);

  }

}

// Check if this coding block, of size bsize, should be considered for refresh

// (lower-qp coding). Decision can be based on various factors, such as

// size of the coding block (i.e., below min_block size rejected), coding

// mode, and rate/distortion.

static int candidate_refresh_aq(const CYCLIC_REFRESH *cr,

                                const MB_MODE_INFO *mbmi, int64_t rate,

                                int64_t dist, BLOCK_SIZE bsize,

                                int noise_level) {

  MV mv = mbmi->mv[0].as_mv;

  int is_compound = has_second_ref(mbmi);

  // Reject the block for lower-qp coding for non-compound mode if

  // projected distortion is above the threshold, and any of the following

  // is true:

  // 1) mode uses large mv

  // 2) mode is an intra-mode

  // Otherwise accept for refresh.

  if (!is_compound && dist > cr->thresh_dist_sb &&

      (mv.row > cr->motion_thresh || mv.row < -cr->motion_thresh ||

       mv.col > cr->motion_thresh || mv.col < -cr->motion_thresh ||

       !is_inter_block(mbmi)))

    return CR_SEGMENT_ID_BASE;

  else if ((is_compound && noise_level < kMedium) ||

           (bsize >= BLOCK_16X16 && rate < cr->thresh_rate_sb &&

            is_inter_block(mbmi) && mbmi->mv[0].as_int == 0 &&

            cr->rate_boost_fac > 10))

    // More aggressive delta-q for bigger blocks with zero motion.

    return CR_SEGMENT_ID_BOOST2;

  else

    return CR_SEGMENT_ID_BOOST1;

}

// Compute delta-q for the segment.

static int compute_deltaq(const AV1_COMP *cpi, int q, double rate_factor) {

  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  int deltaq = av1_compute_qdelta_by_rate(

      cpi, cpi->common.current_frame.frame_type, q, rate_factor);

  if ((-deltaq) > cr->max_qdelta_perc * q / 100) {

    deltaq = -cr->max_qdelta_perc * q / 100;

  }

  return deltaq;

}

int av1_cyclic_refresh_estimate_bits_at_q(const AV1_COMP *cpi,

                                          double correction_factor) {

  const AV1_COMMON *const cm = &cpi->common;

  const int base_qindex = cm->quant_params.base_qindex;

  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int mbs = cm->mi_params.MBs;

  const int num4x4bl = mbs << 4;

  // Weight for non-base segments: use actual number of blocks refreshed in

  // previous/just encoded frame. Note number of blocks here is in 4x4 units.

  double weight_segment1 = (double)cr->actual_num_seg1_blocks / num4x4bl;

  double weight_segment2 = (double)cr->actual_num_seg2_blocks / num4x4bl;

  if (cpi->rc.rtc_external_ratectrl) {

    weight_segment1 = (double)(cr->percent_refresh * cm->mi_params.mi_rows *

                               cm->mi_params.mi_cols / 100) /

                      num4x4bl;

    weight_segment2 = 0;

  }

  // Take segment weighted average for estimated bits.

  const int estimated_bits = (int)round(

      (1.0 - weight_segment1 - weight_segment2) *

          av1_estimate_bits_at_q(cpi, base_qindex, correction_factor) +

      weight_segment1 *

          av1_estimate_bits_at_q(cpi, base_qindex + cr->qindex_delta[1],

                                 correction_factor) +

      weight_segment2 *

          av1_estimate_bits_at_q(cpi, base_qindex + cr->qindex_delta[2],

                                 correction_factor));

  return estimated_bits;

}

int av1_cyclic_refresh_rc_bits_per_mb(const AV1_COMP *cpi, int i,

                                      double correction_factor) {

  const AV1_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  int bits_per_mb;

  int num4x4bl = cm->mi_params.MBs << 4;

  // Weight for segment prior to encoding: take the average of the target

  // number for the frame to be encoded and the actual from the previous frame.

  double weight_segment =

      (double)((cr->target_num_seg_blocks + cr->actual_num_seg1_blocks +

                cr->actual_num_seg2_blocks) >>

               1) /

      num4x4bl;

  if (cpi->rc.rtc_external_ratectrl) {

    weight_segment = (double)((cr->target_num_seg_blocks +

                               cr->percent_refresh * cm->mi_params.mi_rows *

                                   cm->mi_params.mi_cols / 100) >>

                              1) /

                     num4x4bl;

  }

  // Compute delta-q corresponding to qindex i.

  int deltaq = compute_deltaq(cpi, i, cr->rate_ratio_qdelta);

  const int accurate_estimate = cpi->sf.hl_sf.accurate_bit_estimate;

  // Take segment weighted average for bits per mb.

  bits_per_mb = (int)round(

      (1.0 - weight_segment) *

          av1_rc_bits_per_mb(cpi, cm->current_frame.frame_type, i,

                             correction_factor, accurate_estimate) +

      weight_segment * av1_rc_bits_per_mb(cpi, cm->current_frame.frame_type,

                                          i + deltaq, correction_factor,

                                          accurate_estimate));

  return bits_per_mb;

}

void av1_cyclic_reset_segment_skip(const AV1_COMP *cpi, MACROBLOCK *const x,

                                   int mi_row, int mi_col, BLOCK_SIZE bsize,

                                   RUN_TYPE dry_run) {

  int cdf_num;

  const AV1_COMMON *const cm = &cpi->common;

  MACROBLOCKD *const xd = &x->e_mbd;

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

  const int prev_segment_id = mbmi->segment_id;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int bw = mi_size_wide[bsize];

  const int bh = mi_size_high[bsize];

  const int xmis = AOMMIN(cm->mi_params.mi_cols - mi_col, bw);

  const int ymis = AOMMIN(cm->mi_params.mi_rows - mi_row, bh);

  assert(cm->seg.enabled);

  if (!cr->skip_over4x4) {

    mbmi->segment_id =

        av1_get_spatial_seg_pred(cm, xd, &cdf_num, cr->skip_over4x4);

    if (prev_segment_id != mbmi->segment_id) {

      const int block_index = mi_row * cm->mi_params.mi_cols + mi_col;

      const int mi_stride = cm->mi_params.mi_cols;

      const uint8_t segment_id = mbmi->segment_id;

      for (int mi_y = 0; mi_y < ymis; mi_y++) {

        const int map_offset = block_index + mi_y * mi_stride;

        memset(&cr->map[map_offset], 0, xmis);

        memset(&cpi->enc_seg.map[map_offset], segment_id, xmis);

        memset(&cm->cur_frame->seg_map[map_offset], segment_id, xmis);

      }

    }

  }

  if (!dry_run) {

    if (cyclic_refresh_segment_id(prev_segment_id) == CR_SEGMENT_ID_BOOST1)

      x->actual_num_seg1_blocks -= xmis * ymis;

    else if (cyclic_refresh_segment_id(prev_segment_id) == CR_SEGMENT_ID_BOOST2)

      x->actual_num_seg2_blocks -= xmis * ymis;

  }

}

void av1_cyclic_refresh_update_segment(const AV1_COMP *cpi, MACROBLOCK *const x,

                                       int mi_row, int mi_col, BLOCK_SIZE bsize,

                                       int64_t rate, int64_t dist, int skip,

                                       RUN_TYPE dry_run) {

  const AV1_COMMON *const cm = &cpi->common;

  MACROBLOCKD *const xd = &x->e_mbd;

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

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int bw = mi_size_wide[bsize];

  const int bh = mi_size_high[bsize];

  const int xmis = AOMMIN(cm->mi_params.mi_cols - mi_col, bw);

  const int ymis = AOMMIN(cm->mi_params.mi_rows - mi_row, bh);

  const int block_index = mi_row * cm->mi_params.mi_cols + mi_col;

  int noise_level = 0;

  if (cpi->noise_estimate.enabled) noise_level = cpi->noise_estimate.level;

  const int refresh_this_block =

      candidate_refresh_aq(cr, mbmi, rate, dist, bsize, noise_level);

  int sh = cpi->cyclic_refresh->skip_over4x4 ? 2 : 1;

  // Default is to not update the refresh map.

  int new_map_value = cr->map[block_index];

  // If this block is labeled for refresh, check if we should reset the

  // segment_id.

  if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {

    mbmi->segment_id = refresh_this_block;

    // Reset segment_id if will be skipped.

    if (skip) mbmi->segment_id = CR_SEGMENT_ID_BASE;

  }

  const uint8_t segment_id = mbmi->segment_id;

  // Update the cyclic refresh map, to be used for setting segmentation map

  // for the next frame. If the block  will be refreshed this frame, mark it

  // as clean. The magnitude of the -ve influences how long before we consider

  // it for refresh again.

  if (cyclic_refresh_segment_id_boosted(segment_id)) {

    new_map_value = -cr->time_for_refresh;

  } else if (refresh_this_block) {

    // Else if it is accepted as candidate for refresh, and has not already

    // been refreshed (marked as 1) then mark it as a candidate for cleanup

    // for future time (marked as 0), otherwise don't update it.

    if (cr->map[block_index] == 1) new_map_value = 0;

  } else {

    // Leave it marked as block that is not candidate for refresh.

    new_map_value = 1;

  }

  // Update entries in the cyclic refresh map with new_map_value, and

  // copy mbmi->segment_id into global segmentation map.

  const int mi_stride = cm->mi_params.mi_cols;

  for (int mi_y = 0; mi_y < ymis; mi_y += sh) {

    const int map_offset = block_index + mi_y * mi_stride;

    memset(&cr->map[map_offset], new_map_value, xmis);

    memset(&cpi->enc_seg.map[map_offset], segment_id, xmis);

    memset(&cm->cur_frame->seg_map[map_offset], segment_id, xmis);

  }

  // Accumulate cyclic refresh update counters.

  if (!dry_run) {

    if (cyclic_refresh_segment_id(segment_id) == CR_SEGMENT_ID_BOOST1)

      x->actual_num_seg1_blocks += xmis * ymis;

    else if (cyclic_refresh_segment_id(segment_id) == CR_SEGMENT_ID_BOOST2)

      x->actual_num_seg2_blocks += xmis * ymis;

  }

}

// Initializes counters used for cyclic refresh.

void av1_init_cyclic_refresh_counters(MACROBLOCK *const x) {

  x->actual_num_seg1_blocks = 0;

  x->actual_num_seg2_blocks = 0;

}

// Accumulate cyclic refresh counters.

void av1_accumulate_cyclic_refresh_counters(

    CYCLIC_REFRESH *const cyclic_refresh, const MACROBLOCK *const x) {

  cyclic_refresh->actual_num_seg1_blocks += x->actual_num_seg1_blocks;

  cyclic_refresh->actual_num_seg2_blocks += x->actual_num_seg2_blocks;

}

void av1_cyclic_refresh_set_golden_update(AV1_COMP *const cpi) {

  RATE_CONTROL *const rc = &cpi->rc;

  PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  // Set minimum gf_interval for GF update to a multiple of the refresh period,

  // with some max limit. Depending on past encoding stats, GF flag may be

  // reset and update may not occur until next baseline_gf_interval.

  const int gf_length_mult[2] = { 8, 4 };

  if (cr->percent_refresh > 0)

    p_rc->baseline_gf_interval =

        AOMMIN(gf_length_mult[cpi->sf.rt_sf.gf_length_lvl] *

                   (100 / cr->percent_refresh),

               MAX_GF_INTERVAL_RT);

  else

    p_rc->baseline_gf_interval = FIXED_GF_INTERVAL_RT;

  if (rc->avg_frame_low_motion && rc->avg_frame_low_motion < 40)

    p_rc->baseline_gf_interval = 16;

}

// Update the segmentation map, and related quantities: cyclic refresh map,

// refresh sb_index, and target number of blocks to be refreshed.

// The map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or to

// 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock.

// Blocks labeled as BOOST1 may later get set to BOOST2 (during the

// encoding of the superblock).

static void cyclic_refresh_update_map(AV1_COMP *const cpi) {

  AV1_COMMON *const cm = &cpi->common;

  const CommonModeInfoParams *const mi_params = &cm->mi_params;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  unsigned char *const seg_map = cpi->enc_seg.map;

  unsigned char *const active_map_4x4 = cpi->active_map.map;

  int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame;

  int xmis, ymis, x, y;

  uint64_t sb_sad = 0;

  uint64_t thresh_sad_low = 0;

  uint64_t thresh_sad = INT64_MAX;

  const int mi_rows = mi_params->mi_rows, mi_cols = mi_params->mi_cols;

  const int mi_stride = mi_cols;

  // Don't set seg_map to 0 if active_maps is enabled. Active_maps will set

  // seg_map to either 7 or 0 (AM_SEGMENT_ID_INACTIVE/ACTIVE), and cyclic

  // refresh set below (segment 1 or 2) will only be set for ACTIVE blocks.

  if (!cpi->active_map.enabled) {

    memset(seg_map, CR_SEGMENT_ID_BASE, mi_rows * mi_cols);

  }

  sb_cols = (mi_cols + cm->seq_params->mib_size - 1) / cm->seq_params->mib_size;

  sb_rows = (mi_rows + cm->seq_params->mib_size - 1) / cm->seq_params->mib_size;

  sbs_in_frame = sb_cols * sb_rows;

  // Number of target blocks to get the q delta (segment 1).

  block_count = cr->percent_refresh * mi_rows * mi_cols / 100;

  // Set the segmentation map: cycle through the superblocks, starting at

  // cr->mb_index, and stopping when either block_count blocks have been found

  // to be refreshed, or we have passed through whole frame.

  if (cr->sb_index >= sbs_in_frame) cr->sb_index = 0;

  assert(cr->sb_index < sbs_in_frame);

  i = cr->sb_index;

  cr->last_sb_index = cr->sb_index;

  cr->target_num_seg_blocks = 0;

  do {

    int sum_map = 0;

    // Get the mi_row/mi_col corresponding to superblock index i.

    int sb_row_index = (i / sb_cols);

    int sb_col_index = i - sb_row_index * sb_cols;

    int mi_row = sb_row_index * cm->seq_params->mib_size;

    int mi_col = sb_col_index * cm->seq_params->mib_size;

    assert(mi_row >= 0 && mi_row < mi_rows);

    assert(mi_col >= 0 && mi_col < mi_cols);

    bl_index = mi_row * mi_stride + mi_col;

    // Loop through all MI blocks in superblock and update map.

    xmis = AOMMIN(mi_cols - mi_col, cm->seq_params->mib_size);

    ymis = AOMMIN(mi_rows - mi_row, cm->seq_params->mib_size);

    if (cr->use_block_sad_scene_det && cpi->rc.frames_since_key > 30 &&

        cr->counter_encode_maxq_scene_change > 30 &&

        cpi->src_sad_blk_64x64 != NULL &&

        cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1) {

      sb_sad = cpi->src_sad_blk_64x64[sb_col_index + sb_cols * sb_row_index];

      int scale = (cm->width * cm->height < 640 * 360) ? 6 : 8;

      int scale_low = 2;

      thresh_sad = (scale * 64 * 64);

      thresh_sad_low = (scale_low * 64 * 64);

      // For temporal layers: the base temporal layer (temporal_layer_id = 0)

      // has larger frame separation (2 or 4 frames apart), so use larger sad

      // thresholds to compensate for larger frame sad. The larger thresholds

      // also increase the amount of refresh, which is needed for the base

      // temporal layer.

      if (cpi->svc.number_temporal_layers > 1 &&

          cpi->svc.temporal_layer_id == 0) {

        thresh_sad <<= 4;

        thresh_sad_low <<= 2;

      }

    }

    // cr_map only needed at 8x8 blocks.

    for (y = 0; y < ymis; y += 2) {

      for (x = 0; x < xmis; x += 2) {

        const int bl_index2 = bl_index + y * mi_stride + x;

        // If the block is as a candidate for clean up then mark it

        // for possible boost/refresh (segment 1). The segment id may get

        // reset to 0 later if block gets coded anything other than low motion.

        // If the block_sad (sb_sad) is very low label it for refresh anyway.

        // If active_maps is enabled, only allow for setting on ACTIVE blocks.

        if ((cr->map[bl_index2] == 0 || sb_sad < thresh_sad_low) &&

            (!cpi->active_map.enabled ||

             active_map_4x4[bl_index2] == AM_SEGMENT_ID_ACTIVE)) {

          sum_map += 4;

        } else if (cr->map[bl_index2] < 0) {

          cr->map[bl_index2]++;

        }

      }

    }

    // Enforce constant segment over superblock.

    // If segment is at least half of superblock, set to 1.

    // Enforce that block sad (sb_sad) is not too high.

    if (sum_map >= (xmis * ymis) >> 1 && sb_sad < thresh_sad) {

      set_segment_id(seg_map, bl_index, xmis, ymis, mi_stride,

                     CR_SEGMENT_ID_BOOST1);

      cr->target_num_seg_blocks += xmis * ymis;

    }

    i++;

    if (i == sbs_in_frame) {

      i = 0;

    }

  } while (cr->target_num_seg_blocks < block_count && i != cr->sb_index);

  cr->sb_index = i;

  if (cr->target_num_seg_blocks == 0) {

    // Disable segmentation, seg_map is already set to 0 above.

    // Don't disable if active_map is being used.

    if (!cpi->active_map.enabled) av1_disable_segmentation(&cm->seg);

  }

}

static int is_scene_change_detected(AV1_COMP *const cpi) {

  return cpi->rc.high_source_sad;

}

// Set cyclic refresh parameters.

void av1_cyclic_refresh_update_parameters(AV1_COMP *const cpi) {

  // TODO(marpan): Parameters need to be tuned.

  const RATE_CONTROL *const rc = &cpi->rc;

  const PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

  const AV1_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  SVC *const svc = &cpi->svc;

  const int qp_thresh = AOMMAX(16, rc->best_quality + 4);

  const int qp_max_thresh = 118 * MAXQ >> 7;

  const int scene_change_detected = is_scene_change_detected(cpi);

  const int is_screen_content =

      (cpi->oxcf.tune_cfg.content == AOM_CONTENT_SCREEN);

  // A scene change or key frame marks the start of a cyclic refresh cycle.

  const int frames_since_scene_change =

      (cpi->ppi->use_svc || !is_screen_content)

          ? cpi->rc.frames_since_key

          : AOMMIN(cpi->rc.frames_since_key,

                   cr->counter_encode_maxq_scene_change);

  // Cases to reset the cyclic refresh adjustment parameters.

  if (frame_is_intra_only(cm) || scene_change_detected ||

      cpi->ppi->rtc_ref.bias_recovery_frame) {

    // Reset adaptive elements for intra only frames and scene changes.

    cr->percent_refresh_adjustment = 5;

    cr->rate_ratio_qdelta_adjustment = 0.25;

  }

  // Although this segment feature for RTC is only used for

  // blocks >= 8X8, for more efficient coding of the seg map

  // cur_frame->seg_map needs to set at 4x4 along with the

  // function av1_cyclic_reset_segment_skip(). Skipping over

  // 4x4 will therefore have small bdrate loss (~0.2%), so

  // we use it only for speed > 9 for now.

  cr->skip_over4x4 = (cpi->oxcf.speed > 9) ? 1 : 0;

  // should we enable cyclic refresh on this frame.

  cr->apply_cyclic_refresh = 1;

  if (frame_is_intra_only(cm) || is_lossless_requested(&cpi->oxcf.rc_cfg) ||

      cpi->rc.high_motion_content_screen_rtc || scene_change_detected ||

      svc->temporal_layer_id > 0 ||

      svc->prev_number_spatial_layers != svc->number_spatial_layers ||

      p_rc->avg_frame_qindex[INTER_FRAME] < qp_thresh ||

      (svc->number_spatial_layers > 1 &&

       svc->layer_context[svc->temporal_layer_id].is_key_frame) ||

      (frames_since_scene_change > 20 &&

       p_rc->avg_frame_qindex[INTER_FRAME] > qp_max_thresh) ||

      (rc->avg_frame_low_motion && rc->avg_frame_low_motion < 30 &&

       frames_since_scene_change > 40) ||

      cpi->ppi->rtc_ref.bias_recovery_frame) {

    cr->apply_cyclic_refresh = 0;

    return;

  }

  // Increase the amount of refresh for #temporal_layers > 2

  if (svc->number_temporal_layers > 2)

    cr->percent_refresh = 15;

  else

    cr->percent_refresh = 10 + cr->percent_refresh_adjustment;

  if (cpi->active_map.enabled) {

    // Scale down the percent_refresh to target the active blocks only.

    cr->percent_refresh =

        cr->percent_refresh * (100 - cpi->rc.percent_blocks_inactive) / 100;

    if (cr->percent_refresh == 0) {

      cr->apply_cyclic_refresh = 0;

    }

  }

  cr->max_qdelta_perc = 60;

  cr->time_for_refresh = 0;

  cr->use_block_sad_scene_det =

      (cpi->oxcf.tune_cfg.content != AOM_CONTENT_SCREEN &&

       cm->seq_params->sb_size == BLOCK_64X64)

          ? 1

          : 0;

  cr->motion_thresh = 32;

  cr->rate_boost_fac =

      (cpi->oxcf.tune_cfg.content == AOM_CONTENT_SCREEN) ? 10 : 15;

  // Use larger delta-qp (increase rate_ratio_qdelta) for first few

  // refresh cycles after a key frame (svc) or scene change (non svc).

  // For non svc screen content, after a scene change gradually reduce

  // this boost and supress it further if either of the previous two

  // frames overshot.

  if (cr->percent_refresh > 0) {

    if (cpi->ppi->use_svc || !is_screen_content) {

      if (frames_since_scene_change <

          ((4 * svc->number_temporal_layers) * (100 / cr->percent_refresh))) {

        cr->rate_ratio_qdelta = 3.0 + cr->rate_ratio_qdelta_adjustment;

      } else {

        cr->rate_ratio_qdelta = 2.25 + cr->rate_ratio_qdelta_adjustment;

      }

    } else {

      double distance_from_sc_factor =

          AOMMIN(0.75, (int)(frames_since_scene_change / 10) * 0.1);

      cr->rate_ratio_qdelta =

          3.0 + cr->rate_ratio_qdelta_adjustment - distance_from_sc_factor;

      if ((frames_since_scene_change < 10) &&

          ((cpi->rc.rc_1_frame < 0) || (cpi->rc.rc_2_frame < 0))) {

        cr->rate_ratio_qdelta -= 0.25;

      }

    }

  } else {

    cr->rate_ratio_qdelta = 2.25 + cr->rate_ratio_qdelta_adjustment;

  }

  // Adjust some parameters for low resolutions.

  if (cm->width * cm->height <= 352 * 288) {

    if (cpi->svc.number_temporal_layers > 1) {

      cr->motion_thresh = 32;

      cr->rate_boost_fac = 13;

    } else {

      if (rc->avg_frame_bandwidth < 3000) {

        cr->motion_thresh = 16;

        cr->rate_boost_fac = 13;

      } else {

        cr->max_qdelta_perc = 50;

        cr->rate_ratio_qdelta = AOMMAX(cr->rate_ratio_qdelta, 2.0);

      }

    }

  }

  if (cpi->oxcf.rc_cfg.mode == AOM_VBR) {

    // To be adjusted for VBR mode, e.g., based on gf period and boost.

    // For now use smaller qp-delta (than CBR), no second boosted seg, and

    // turn-off (no refresh) on golden refresh (since it's already boosted).

    cr->percent_refresh = 10;

    cr->rate_ratio_qdelta = 1.5;

    cr->rate_boost_fac = 10;

    if (cpi->refresh_frame.golden_frame) {

      cr->percent_refresh = 0;

      cr->rate_ratio_qdelta = 1.0;

    }

  }

  if (rc->rtc_external_ratectrl) {

    cr->actual_num_seg1_blocks = cr->percent_refresh * cm->mi_params.mi_rows *

                                 cm->mi_params.mi_cols / 100;

    cr->actual_num_seg2_blocks = 0;

  }

}

static void cyclic_refresh_reset_resize(AV1_COMP *const cpi) {

  const AV1_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  memset(cr->map, 0, cm->mi_params.mi_rows * cm->mi_params.mi_cols);

  cr->sb_index = 0;

  cr->last_sb_index = 0;

  cpi->refresh_frame.golden_frame = true;

  cr->apply_cyclic_refresh = 0;

  cr->counter_encode_maxq_scene_change = 0;

  cr->percent_refresh_adjustment = 5;

  cr->rate_ratio_qdelta_adjustment = 0.25;

}

// Setup cyclic background refresh: set delta q and segmentation map.

void av1_cyclic_refresh_setup(AV1_COMP *const cpi) {

  AV1_COMMON *const cm = &cpi->common;

  const RATE_CONTROL *const rc = &cpi->rc;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  struct segmentation *const seg = &cm->seg;

  const int scene_change_detected = is_scene_change_detected(cpi);

  const GF_GROUP *const gf_group = &cpi->ppi->gf_group;

  const int boost_index = AOMMIN(15, (cpi->ppi->p_rc.gfu_boost / 100));

  const int layer_depth = AOMMIN(gf_group->layer_depth[cpi->gf_frame_index], 6);

  const FRAME_TYPE frame_type = cm->current_frame.frame_type;

  // Set resolution_change flag: for svc only set it when the

  // number of spatial layers has not changed.

  const int resolution_change =

      cm->prev_frame &&

      (cm->width != cm->prev_frame->width ||

       cm->height != cm->prev_frame->height) &&

      cpi->svc.prev_number_spatial_layers == cpi->svc.number_spatial_layers;

  if (resolution_change) cyclic_refresh_reset_resize(cpi);

  if (!cr->apply_cyclic_refresh) {

    // Don't disable and set seg_map to 0 if active_maps is enabled, unless

    // whole frame is set as inactive (since we only apply cyclic_refresh to

    // active blocks).

    if (!cpi->active_map.enabled || cpi->rc.percent_blocks_inactive == 100) {

      unsigned char *const seg_map = cpi->enc_seg.map;

      memset(seg_map, 0, cm->mi_params.mi_rows * cm->mi_params.mi_cols);

      av1_disable_segmentation(&cm->seg);

    }

    if (frame_is_intra_only(cm) || scene_change_detected ||

        cpi->ppi->rtc_ref.bias_recovery_frame) {

      cr->sb_index = 0;

      cr->last_sb_index = 0;

      cr->counter_encode_maxq_scene_change = 0;

      cr->actual_num_seg1_blocks = 0;

      cr->actual_num_seg2_blocks = 0;

    }

    return;

  } else {

    cr->counter_encode_maxq_scene_change++;

    const double q = av1_convert_qindex_to_q(cm->quant_params.base_qindex,

                                             cm->seq_params->bit_depth);

    // Set rate threshold to some multiple (set to 2 for now) of the target

    // rate (target is given by sb64_target_rate and scaled by 256).

    cr->thresh_rate_sb = ((int64_t)(rc->sb64_target_rate) << 8) << 2;

    // Distortion threshold, quadratic in Q, scale factor to be adjusted.

    // q will not exceed 457, so (q * q) is within 32bit; see:

    // av1_convert_qindex_to_q(), av1_ac_quant(), ac_qlookup*[].

    cr->thresh_dist_sb = ((int64_t)(q * q)) << 2;

    // For low-resoln or lower speeds, the rate/dist thresholds need to be

    // tuned/updated.

    if (cpi->oxcf.speed <= 7 || (cm->width * cm->height < 640 * 360)) {

      cr->thresh_dist_sb = 0;

      cr->thresh_rate_sb = INT64_MAX;

    }

    // Set up segmentation.

    av1_enable_segmentation(&cm->seg);

    if (!cpi->active_map.enabled) {

      // Clear down the segment map, only if active_maps is not enabled.

      av1_clearall_segfeatures(seg);

    }

    // Note: setting temporal_update has no effect, as the seg-map coding method

    // (temporal or spatial) is determined in

    // av1_choose_segmap_coding_method(),

    // based on the coding cost of each method. For error_resilient mode on the

    // last_frame_seg_map is set to 0, so if temporal coding is used, it is

    // relative to 0 previous map.

    // seg->temporal_update = 0;

    // Segment BASE "Q" feature is disabled so it defaults to the baseline Q.

    av1_disable_segfeature(seg, CR_SEGMENT_ID_BASE, SEG_LVL_ALT_Q);

    // Use segment BOOST1 for in-frame Q adjustment.

    av1_enable_segfeature(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q);

    // Use segment BOOST2 for more aggressive in-frame Q adjustment.

    av1_enable_segfeature(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q);

    // Set the q delta for segment BOOST1.

    const CommonQuantParams *const quant_params = &cm->quant_params;

    int qindex_delta =

        compute_deltaq(cpi, quant_params->base_qindex, cr->rate_ratio_qdelta);

    cr->qindex_delta[1] = qindex_delta;

    // Compute rd-mult for segment BOOST1.

    const int qindex2 = clamp(

        quant_params->base_qindex + quant_params->y_dc_delta_q + qindex_delta,

        0, MAXQ);

    cr->rdmult = av1_compute_rd_mult(

        qindex2, cm->seq_params->bit_depth,

        cpi->ppi->gf_group.update_type[cpi->gf_frame_index], layer_depth,

        boost_index, frame_type, cpi->oxcf.q_cfg.use_fixed_qp_offsets,

        is_stat_consumption_stage(cpi), cpi->oxcf.tune_cfg.tuning);

    av1_set_segdata(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q, qindex_delta);

    // Set a more aggressive (higher) q delta for segment BOOST2.

    qindex_delta = compute_deltaq(

        cpi, quant_params->base_qindex,

        AOMMIN(CR_MAX_RATE_TARGET_RATIO,

               0.1 * cr->rate_boost_fac * cr->rate_ratio_qdelta));

    cr->qindex_delta[2] = qindex_delta;

    av1_set_segdata(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q, qindex_delta);

    // Update the segmentation and refresh map.

    cyclic_refresh_update_map(cpi);

  }

}

int av1_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) {

  return cr->rdmult;

}

int av1_cyclic_refresh_disable_lf_cdef(AV1_COMP *const cpi) {

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int qindex = cpi->common.quant_params.base_qindex;

  if (cpi->active_map.enabled &&

      cpi->rc.percent_blocks_inactive >

          cpi->sf.rt_sf.thresh_active_maps_skip_lf_cdef)

    return 1;

  if (cpi->rc.frames_since_key > 30 && cr->percent_refresh > 0 &&

      cr->counter_encode_maxq_scene_change > 300 / cr->percent_refresh &&

      cpi->rc.frame_source_sad < 1000 &&

      qindex < 7 * (cpi->rc.worst_quality >> 3))

    return 1;

  // More aggressive skip.

  else if (cpi->sf.rt_sf.skip_lf_screen > 1 && !cpi->rc.high_source_sad &&

           cpi->rc.frame_source_sad < 50000 && qindex < cpi->rc.worst_quality)

    return 1;

  return 0;

}