/*

 *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.

 *

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

 */

#include <limits.h>

#include <math.h>

#include "vpx_dsp/vpx_dsp_common.h"

#include "vpx_ports/system_state.h"

#include "vp9/encoder/vp9_aq_cyclicrefresh.h"

#include "vp9/common/vp9_seg_common.h"

#include "vp9/encoder/vp9_ratectrl.h"

#include "vp9/encoder/vp9_segmentation.h"

static const uint8_t VP9_VAR_OFFS[64] = {

  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,

  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,

  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,

  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,

  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128

};

CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) {

  size_t last_coded_q_map_size;

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

  if (cr == NULL) return NULL;

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

  if (cr->map == NULL) {

    vp9_cyclic_refresh_free(cr);

    return NULL;

  }

  last_coded_q_map_size = mi_rows * mi_cols * sizeof(*cr->last_coded_q_map);

  cr->last_coded_q_map = vpx_malloc(last_coded_q_map_size);

  if (cr->last_coded_q_map == NULL) {

    vp9_cyclic_refresh_free(cr);

    return NULL;

  }

  assert(MAXQ <= 255);

  memset(cr->last_coded_q_map, MAXQ, last_coded_q_map_size);

  cr->counter_encode_maxq_scene_change = 0;

  cr->content_mode = 1;

  return cr;

}

void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) {

  if (cr != NULL) {

    vpx_free(cr->map);

    vpx_free(cr->last_coded_q_map);

    vpx_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 MODE_INFO *mi,

                                int64_t rate, int64_t dist, int bsize) {

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

  // Reject the block for lower-qp coding 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 (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(mi)))

    return CR_SEGMENT_ID_BASE;

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

           is_inter_block(mi) && mi->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 VP9_COMP *cpi, int q, double rate_factor) {

  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

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

  int deltaq = vp9_compute_qdelta_by_rate(rc, cpi->common.frame_type, q,

                                          rate_factor, cpi->common.bit_depth);

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

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

  }

  return deltaq;

}

// For the just encoded frame, estimate the bits, incorporating the delta-q

// from non-base segment. For now ignore effect of multiple segments

// (with different delta-q). Note this function is called in the postencode

// (called from rc_update_rate_correction_factors()).

int vp9_cyclic_refresh_estimate_bits_at_q(const VP9_COMP *cpi,

                                          double correction_factor) {

  const VP9_COMMON *const cm = &cpi->common;

  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  int estimated_bits;

  int mbs = cm->MBs;

  int num8x8bl = mbs << 2;

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

  // previous/just encoded frame. Note number of blocks here is in 8x8 units.

  double weight_segment1 = (double)cr->actual_num_seg1_blocks / num8x8bl;

  double weight_segment2 = (double)cr->actual_num_seg2_blocks / num8x8bl;

  // Take segment weighted average for estimated bits.

  estimated_bits = (int)round(

      (1.0 - weight_segment1 - weight_segment2) *

          vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex, mbs,

                                 correction_factor, cm->bit_depth) +

      weight_segment1 *

          vp9_estimate_bits_at_q(cm->frame_type,

                                 cm->base_qindex + cr->qindex_delta[1], mbs,

                                 correction_factor, cm->bit_depth) +

      weight_segment2 *

          vp9_estimate_bits_at_q(cm->frame_type,

                                 cm->base_qindex + cr->qindex_delta[2], mbs,

                                 correction_factor, cm->bit_depth));

  return estimated_bits;

}

// Prior to encoding the frame, estimate the bits per mb, for a given q = i and

// a corresponding delta-q (for segment 1). This function is called in the

// rc_regulate_q() to set the base qp index.

// Note: the segment map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or

// to 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock, prior to encoding.

int vp9_cyclic_refresh_rc_bits_per_mb(const VP9_COMP *cpi, int i,

                                      double correction_factor) {

  const VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  int bits_per_mb;

  int deltaq = 0;

  if (cpi->oxcf.speed < 8)

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

  else

    deltaq = -(cr->max_qdelta_perc * i) / 200;

  // Take segment weighted average for bits per mb.

  bits_per_mb =

      (int)round((1.0 - cr->weight_segment) *

                     vp9_rc_bits_per_mb(cm->frame_type, i, correction_factor,

                                        cm->bit_depth) +

                 cr->weight_segment *

                     vp9_rc_bits_per_mb(cm->frame_type, i + deltaq,

                                        correction_factor, cm->bit_depth));

  return bits_per_mb;

}

// Prior to coding a given prediction block, of size bsize at (mi_row, mi_col),

// check if we should reset the segment_id, and update the cyclic_refresh map

// and segmentation map.

void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi, MODE_INFO *const mi,

                                       int mi_row, int mi_col, BLOCK_SIZE bsize,

                                       int64_t rate, int64_t dist, int skip,

                                       struct macroblock_plane *const p) {

  const VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int bw = num_8x8_blocks_wide_lookup[bsize];

  const int bh = num_8x8_blocks_high_lookup[bsize];

  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);

  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);

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

  int refresh_this_block = candidate_refresh_aq(cr, mi, rate, dist, bsize);

  // Default is to not update the refresh map.

  int new_map_value = cr->map[block_index];

  int x = 0;

  int y = 0;

  int is_skin = 0;

  if (refresh_this_block == 0 && bsize <= BLOCK_16X16 &&

      cpi->use_skin_detection) {

    is_skin =

        vp9_compute_skin_block(p[0].src.buf, p[1].src.buf, p[2].src.buf,

                               p[0].src.stride, p[1].src.stride, bsize, 0, 0);

    if (is_skin) refresh_this_block = 1;

  }

  if (cpi->oxcf.rc_mode == VPX_VBR && mi->ref_frame[0] == GOLDEN_FRAME)

    refresh_this_block = 0;

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

  // segment_id.

  if (cpi->sf.use_nonrd_pick_mode &&

      cyclic_refresh_segment_id_boosted(mi->segment_id)) {

    mi->segment_id = refresh_this_block;

    // Reset segment_id if it will be skipped.

    if (skip) mi->segment_id = CR_SEGMENT_ID_BASE;

  }

  // 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(mi->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.

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

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

      int map_offset = block_index + y * cm->mi_cols + x;

      cr->map[map_offset] = new_map_value;

      cpi->segmentation_map[map_offset] = mi->segment_id;

    }

}

void vp9_cyclic_refresh_update_sb_postencode(VP9_COMP *const cpi,

                                             const MODE_INFO *const mi,

                                             int mi_row, int mi_col,

                                             BLOCK_SIZE bsize) {

  const VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  const int bw = num_8x8_blocks_wide_lookup[bsize];

  const int bh = num_8x8_blocks_high_lookup[bsize];

  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);

  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);

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

  int x, y;

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

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

      int map_offset = block_index + y * cm->mi_cols + x;

      // Inter skip blocks were clearly not coded at the current qindex, so

      // don't update the map for them. For cases where motion is non-zero or

      // the reference frame isn't the previous frame, the previous value in

      // the map for this spatial location is not entirely correct.

      if ((!is_inter_block(mi) || !mi->skip) &&

          mi->segment_id <= CR_SEGMENT_ID_BOOST2) {

        cr->last_coded_q_map[map_offset] =

            clamp(cm->base_qindex + cr->qindex_delta[mi->segment_id], 0, MAXQ);

      } else if (is_inter_block(mi) && mi->skip &&

                 mi->segment_id <= CR_SEGMENT_ID_BOOST2) {

        cr->last_coded_q_map[map_offset] = VPXMIN(

            clamp(cm->base_qindex + cr->qindex_delta[mi->segment_id], 0, MAXQ),

            cr->last_coded_q_map[map_offset]);

      }

    }

}

// From the just encoded frame: update the actual number of blocks that were

// applied the segment delta q, and the amount of low motion in the frame.

// Also check conditions for forcing golden update, or preventing golden

// update if the period is up.

void vp9_cyclic_refresh_postencode(VP9_COMP *const cpi) {

  VP9_COMMON *const cm = &cpi->common;

  MODE_INFO **mi = cm->mi_grid_visible;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  RATE_CONTROL *const rc = &cpi->rc;

  unsigned char *const seg_map = cpi->segmentation_map;

  double fraction_low = 0.0;

  int force_gf_refresh = 0;

  int low_content_frame = 0;

  int mi_row, mi_col;

  cr->actual_num_seg1_blocks = 0;

  cr->actual_num_seg2_blocks = 0;

  for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {

    for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {

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

      int map_index = mi_row * cm->mi_cols + mi_col;

      if (cyclic_refresh_segment_id(seg_map[map_index]) == CR_SEGMENT_ID_BOOST1)

        cr->actual_num_seg1_blocks++;

      else if (cyclic_refresh_segment_id(seg_map[map_index]) ==

               CR_SEGMENT_ID_BOOST2)

        cr->actual_num_seg2_blocks++;

      // Accumulate low_content_frame.

      if (is_inter_block(mi[0]) && abs(mv.row) < 16 && abs(mv.col) < 16)

        low_content_frame++;

      mi++;

    }

    mi += 8;

  }

  // Check for golden frame update: only for non-SVC and non-golden boost.

  if (!cpi->use_svc && cpi->ext_refresh_frame_flags_pending == 0 &&

      !cpi->oxcf.gf_cbr_boost_pct) {

    // Force this frame as a golden update frame if this frame changes the

    // resolution (resize_pending != 0).

    if (cpi->resize_pending != 0) {

      vp9_cyclic_refresh_set_golden_update(cpi);

      rc->frames_till_gf_update_due = rc->baseline_gf_interval;

      if (rc->frames_till_gf_update_due > rc->frames_to_key)

        rc->frames_till_gf_update_due = rc->frames_to_key;

      cpi->refresh_golden_frame = 1;

      force_gf_refresh = 1;

    }

    // Update average of low content/motion in the frame.

    fraction_low = (double)low_content_frame / (cm->mi_rows * cm->mi_cols);

    cr->low_content_avg = (fraction_low + 3 * cr->low_content_avg) / 4;

    if (!force_gf_refresh && cpi->refresh_golden_frame == 1 &&

        rc->frames_since_key > rc->frames_since_golden + 1) {

      // Don't update golden reference if the amount of low_content for the

      // current encoded frame is small, or if the recursive average of the

      // low_content over the update interval window falls below threshold.

      if (fraction_low < 0.65 || cr->low_content_avg < 0.6) {

        cpi->refresh_golden_frame = 0;

      }

      // Reset for next internal.

      cr->low_content_avg = fraction_low;

    }

  }

}

// Set golden frame update interval, for non-svc 1 pass CBR mode.

void vp9_cyclic_refresh_set_golden_update(VP9_COMP *const cpi) {

  RATE_CONTROL *const rc = &cpi->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.

  if (cr->percent_refresh > 0)

    rc->baseline_gf_interval = VPXMIN(4 * (100 / cr->percent_refresh), 40);

  else

    rc->baseline_gf_interval = 40;

  if (cpi->oxcf.rc_mode == VPX_VBR) rc->baseline_gf_interval = 20;

  if (rc->avg_frame_low_motion < 50 && rc->frames_since_key > 40 &&

      cr->content_mode)

    rc->baseline_gf_interval = 10;

}

static int is_superblock_flat_static(VP9_COMP *const cpi, int sb_row_index,

                                     int sb_col_index) {

  unsigned int source_variance;

  const uint8_t *src_y = cpi->Source->y_buffer;

  const int ystride = cpi->Source->y_stride;

  unsigned int sse;

  const BLOCK_SIZE bsize = BLOCK_64X64;

  src_y += (sb_row_index << 6) * ystride + (sb_col_index << 6);

  source_variance =

      cpi->fn_ptr[bsize].vf(src_y, ystride, VP9_VAR_OFFS, 0, &sse);

  if (source_variance == 0) {

    uint64_t block_sad;

    const uint8_t *last_src_y = cpi->Last_Source->y_buffer;

    const int last_ystride = cpi->Last_Source->y_stride;

    last_src_y += (sb_row_index << 6) * ystride + (sb_col_index << 6);

    block_sad =

        cpi->fn_ptr[bsize].sdf(src_y, ystride, last_src_y, last_ystride);

    if (block_sad == 0) return 1;

  }

  return 0;

}

// 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(VP9_COMP *const cpi) {

  VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  unsigned char *const seg_map = cpi->segmentation_map;

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

  int xmis, ymis, x, y;

  int consec_zero_mv_thresh = 0;

  int qindex_thresh = 0;

  int count_sel = 0;

  int count_tot = 0;

  memset(seg_map, CR_SEGMENT_ID_BASE, cm->mi_rows * cm->mi_cols);

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

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

  sbs_in_frame = sb_cols * sb_rows;

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

  block_count = cr->percent_refresh * cm->mi_rows * cm->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.

  assert(cr->sb_index < sbs_in_frame);

  i = cr->sb_index;

  cr->target_num_seg_blocks = 0;

  if (cpi->oxcf.content != VP9E_CONTENT_SCREEN) {

    consec_zero_mv_thresh = 100;

  }

  qindex_thresh =

      cpi->oxcf.content == VP9E_CONTENT_SCREEN

          ? vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)

          : vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST1, cm->base_qindex);

  // More aggressive settings for noisy content.

  if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium &&

      cr->content_mode) {

    consec_zero_mv_thresh = 60;

    qindex_thresh =

        VPXMAX(vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST1, cm->base_qindex),

               cm->base_qindex);

  }

  do {

    int sum_map = 0;

    int consec_zero_mv_thresh_block = consec_zero_mv_thresh;

    // 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 * MI_BLOCK_SIZE;

    int mi_col = sb_col_index * MI_BLOCK_SIZE;

    int flat_static_blocks = 0;

    int compute_content = 1;

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

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

#if CONFIG_VP9_HIGHBITDEPTH

    if (cpi->common.use_highbitdepth) compute_content = 0;

#endif

    if (cr->content_mode == 0 || cpi->Last_Source == NULL ||

        cpi->Last_Source->y_width != cpi->Source->y_width ||

        cpi->Last_Source->y_height != cpi->Source->y_height)

      compute_content = 0;

    bl_index = mi_row * cm->mi_cols + mi_col;

    // Loop through all 8x8 blocks in superblock and update map.

    xmis =

        VPXMIN(cm->mi_cols - mi_col, num_8x8_blocks_wide_lookup[BLOCK_64X64]);

    ymis =

        VPXMIN(cm->mi_rows - mi_row, num_8x8_blocks_high_lookup[BLOCK_64X64]);

    if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium &&

        (xmis <= 2 || ymis <= 2))

      consec_zero_mv_thresh_block = 4;

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

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

        const int bl_index2 = bl_index + y * cm->mi_cols + 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 depending on the coding mode.

        if (cr->map[bl_index2] == 0) {

          count_tot++;

          if (cr->content_mode == 0 ||

              cr->last_coded_q_map[bl_index2] > qindex_thresh ||

              cpi->consec_zero_mv[bl_index2] < consec_zero_mv_thresh_block) {

            sum_map++;

            count_sel++;

          }

        } 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.

    if (sum_map >= xmis * ymis / 2) {

      // This superblock is a candidate for refresh:

      // compute spatial variance and exclude blocks that are spatially flat

      // and stationary. Note: this is currently only done for screne content

      // mode.

      if (compute_content && cr->skip_flat_static_blocks)

        flat_static_blocks =

            is_superblock_flat_static(cpi, sb_row_index, sb_col_index);

      if (!flat_static_blocks) {

        // Label this superblock as segment 1.

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

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

            seg_map[bl_index + y * cm->mi_cols + x] = 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;

  cr->reduce_refresh = 0;

  if (cpi->oxcf.content != VP9E_CONTENT_SCREEN)

    if (count_sel < (3 * count_tot) >> 2) cr->reduce_refresh = 1;

}

// Set cyclic refresh parameters.

void vp9_cyclic_refresh_update_parameters(VP9_COMP *const cpi) {

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

  const VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  int num8x8bl = cm->MBs << 2;

  int target_refresh = 0;

  double weight_segment_target = 0;

  double weight_segment = 0;

  int thresh_low_motion = 20;

  int qp_thresh = VPXMIN((cpi->oxcf.content == VP9E_CONTENT_SCREEN) ? 35 : 20,

                         rc->best_quality << 1);

  int qp_max_thresh = 117 * MAXQ >> 7;

  cr->apply_cyclic_refresh = 1;

  if (frame_is_intra_only(cm) || cpi->svc.temporal_layer_id > 0 ||

      is_lossless_requested(&cpi->oxcf) ||

      rc->avg_frame_qindex[INTER_FRAME] < qp_thresh ||

      (cpi->use_svc &&

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

      (!cpi->use_svc && cr->content_mode &&

       rc->avg_frame_low_motion < thresh_low_motion &&

       rc->frames_since_key > 40) ||

      (!cpi->use_svc && rc->avg_frame_qindex[INTER_FRAME] > qp_max_thresh &&

       rc->frames_since_key > 20) ||

      (cpi->roi.enabled && cpi->roi.skip[BACKGROUND_SEG_SKIP_ID] &&

       rc->frames_since_key > FRAMES_NO_SKIPPING_AFTER_KEY)) {

    cr->apply_cyclic_refresh = 0;

    return;

  }

  cr->percent_refresh = 10;

  if (cr->reduce_refresh) cr->percent_refresh = 5;

  cr->max_qdelta_perc = 60;

  cr->time_for_refresh = 0;

  cr->motion_thresh = 32;

  cr->rate_boost_fac = 15;

  // Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4)

  // periods of the refresh cycle, after a key frame.

  // Account for larger interval on base layer for temporal layers.

  if (cr->percent_refresh > 0 &&

      rc->frames_since_key <

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

    cr->rate_ratio_qdelta = 3.0;

  } else {

    cr->rate_ratio_qdelta = 2.0;

    if (cr->content_mode && cpi->noise_estimate.enabled &&

        cpi->noise_estimate.level >= kMedium) {

      // Reduce the delta-qp if the estimated source noise is above threshold.

      cr->rate_ratio_qdelta = 1.7;

      cr->rate_boost_fac = 13;

    }

  }

  // For screen-content: keep rate_ratio_qdelta to 2.0 (segment#1 boost) and

  // percent_refresh (refresh rate) to 10. But reduce rate boost for segment#2

  // (rate_boost_fac = 10 disables segment#2).

  if (cpi->oxcf.content == VP9E_CONTENT_SCREEN) {

    // Only enable feature of skipping flat_static blocks for top layer

    // under screen content mode.

    if (cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1)

      cr->skip_flat_static_blocks = 1;

    cr->percent_refresh = (cr->skip_flat_static_blocks) ? 5 : 10;

    // Increase the amount of refresh on scene change that is encoded at max Q,

    // increase for a few cycles of the refresh period (~100 / percent_refresh).

    if (cr->content_mode && cr->counter_encode_maxq_scene_change < 30)

      cr->percent_refresh = (cr->skip_flat_static_blocks) ? 10 : 15;

    cr->rate_ratio_qdelta = 2.0;

    cr->rate_boost_fac = 10;

  }

  // Adjust some parameters for low resolutions.

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

    if (rc->avg_frame_bandwidth < 3000) {

      cr->motion_thresh = 64;

      cr->rate_boost_fac = 13;

    } else {

      cr->max_qdelta_perc = 70;

      cr->rate_ratio_qdelta = VPXMAX(cr->rate_ratio_qdelta, 2.5);

    }

  }

  if (cpi->oxcf.rc_mode == VPX_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_golden_frame == 1 && !cpi->use_svc) {

      cr->percent_refresh = 0;

      cr->rate_ratio_qdelta = 1.0;

    }

  }

  // 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.

  // Use the target if its less. To be used for setting the base qp for the

  // frame in vp9_rc_regulate_q.

  target_refresh = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;

  weight_segment_target = (double)(target_refresh) / num8x8bl;

  weight_segment = (double)((target_refresh + cr->actual_num_seg1_blocks +

                             cr->actual_num_seg2_blocks) >>

                            1) /

                   num8x8bl;

  if (weight_segment_target < 7 * weight_segment / 8)

    weight_segment = weight_segment_target;

  // For screen-content: don't include target for the weight segment,

  // since for all flat areas the segment is reset, so its more accurate

  // to just use the previous actual number of seg blocks for the weight.

  if (cpi->oxcf.content == VP9E_CONTENT_SCREEN)

    weight_segment =

        (double)(cr->actual_num_seg1_blocks + cr->actual_num_seg2_blocks) /

        num8x8bl;

  cr->weight_segment = weight_segment;

  if (cr->content_mode == 0) {

    cr->actual_num_seg1_blocks =

        cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;

    cr->actual_num_seg2_blocks = 0;

    cr->weight_segment = (double)(cr->actual_num_seg1_blocks) / num8x8bl;

  }

}

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

void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {

  VP9_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;

  int scene_change_detected =

      cpi->rc.high_source_sad ||

      (cpi->use_svc && cpi->svc.high_source_sad_superframe);

  if (cm->current_video_frame == 0) cr->low_content_avg = 0.0;

  // Reset if resoluton change has occurred.

  if (cpi->resize_pending != 0) vp9_cyclic_refresh_reset_resize(cpi);

  if (!cr->apply_cyclic_refresh || (cpi->force_update_segmentation) ||

      scene_change_detected) {

    // Set segmentation map to 0 and disable.

    unsigned char *const seg_map = cpi->segmentation_map;

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

    vp9_disable_segmentation(&cm->seg);

    if (cm->frame_type == KEY_FRAME || scene_change_detected) {

      memset(cr->last_coded_q_map, MAXQ,

             cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));

      cr->sb_index = 0;

      cr->reduce_refresh = 0;

      cr->counter_encode_maxq_scene_change = 0;

    }

    return;

  } else {

    int qindex_delta = 0;

    int qindex2;

    const double q = vp9_convert_qindex_to_q(cm->base_qindex, cm->bit_depth);

    cr->counter_encode_maxq_scene_change++;

    vpx_clear_system_state();

    // 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:

    // vp9_convert_qindex_to_q(), vp9_ac_quant(), ac_qlookup*[].

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

    // Set up segmentation.

    // Clear down the segment map.

    vp9_enable_segmentation(&cm->seg);

    vp9_clearall_segfeatures(seg);

    // Select delta coding method.

    seg->abs_delta = SEGMENT_DELTADATA;

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

    // (temporal or spatial) is determined in vp9_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.

    vp9_disable_segfeature(seg, CR_SEGMENT_ID_BASE, SEG_LVL_ALT_Q);

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

    vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q);

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

    vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q);

    // Set the q delta for segment BOOST1.

    qindex_delta = compute_deltaq(cpi, cm->base_qindex, cr->rate_ratio_qdelta);

    cr->qindex_delta[1] = qindex_delta;

    // Compute rd-mult for segment BOOST1.

    qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ);

    cr->rdmult = vp9_compute_rd_mult(cpi, qindex2);

    vp9_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, cm->base_qindex,

        VPXMIN(CR_MAX_RATE_TARGET_RATIO,

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

    cr->qindex_delta[2] = qindex_delta;

    vp9_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 vp9_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) {

  return cr->rdmult;

}

void vp9_cyclic_refresh_reset_resize(VP9_COMP *const cpi) {

  const VP9_COMMON *const cm = &cpi->common;

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

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

  memset(cr->last_coded_q_map, MAXQ,

         cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));

  cr->sb_index = 0;

  cpi->refresh_golden_frame = 1;

  cpi->refresh_alt_ref_frame = 1;

  cr->counter_encode_maxq_scene_change = 0;

}

void vp9_cyclic_refresh_limit_q(const VP9_COMP *cpi, int *q) {

  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

  // For now apply hard limit to frame-level decrease in q, if the cyclic

  // refresh is active (percent_refresh > 0).

  if (cr->percent_refresh > 0 && cpi->rc.q_1_frame - *q > 8) {

    *q = cpi->rc.q_1_frame - 8;

  }

}