1/*
2 *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include <limits.h>
12#include <math.h>
13
14#include "vpx_dsp/vpx_dsp_common.h"
15#include "vpx_ports/system_state.h"
16
17#include "vp9/encoder/vp9_aq_cyclicrefresh.h"
18
19#include "vp9/common/vp9_seg_common.h"
20
21#include "vp9/encoder/vp9_ratectrl.h"
22#include "vp9/encoder/vp9_segmentation.h"
23
24CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) {
25  size_t last_coded_q_map_size;
26  size_t consec_zero_mv_size;
27  CYCLIC_REFRESH *const cr = vpx_calloc(1, sizeof(*cr));
28  if (cr == NULL)
29    return NULL;
30
31  cr->map = vpx_calloc(mi_rows * mi_cols, sizeof(*cr->map));
32  if (cr->map == NULL) {
33    vpx_free(cr);
34    return NULL;
35  }
36  last_coded_q_map_size = mi_rows * mi_cols * sizeof(*cr->last_coded_q_map);
37  cr->last_coded_q_map = vpx_malloc(last_coded_q_map_size);
38  if (cr->last_coded_q_map == NULL) {
39    vpx_free(cr);
40    return NULL;
41  }
42  assert(MAXQ <= 255);
43  memset(cr->last_coded_q_map, MAXQ, last_coded_q_map_size);
44
45  consec_zero_mv_size = mi_rows * mi_cols * sizeof(*cr->consec_zero_mv);
46  cr->consec_zero_mv = vpx_malloc(consec_zero_mv_size);
47  if (cr->consec_zero_mv == NULL) {
48    vpx_free(cr);
49    return NULL;
50  }
51  memset(cr->consec_zero_mv, 0, consec_zero_mv_size);
52  return cr;
53}
54
55void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) {
56  vpx_free(cr->map);
57  vpx_free(cr->last_coded_q_map);
58  vpx_free(cr->consec_zero_mv);
59  vpx_free(cr);
60}
61
62// Check if we should turn off cyclic refresh based on bitrate condition.
63static int apply_cyclic_refresh_bitrate(const VP9_COMMON *cm,
64                                        const RATE_CONTROL *rc) {
65  // Turn off cyclic refresh if bits available per frame is not sufficiently
66  // larger than bit cost of segmentation. Segment map bit cost should scale
67  // with number of seg blocks, so compare available bits to number of blocks.
68  // Average bits available per frame = avg_frame_bandwidth
69  // Number of (8x8) blocks in frame = mi_rows * mi_cols;
70  const float factor = 0.25;
71  const int number_blocks = cm->mi_rows  * cm->mi_cols;
72  // The condition below corresponds to turning off at target bitrates:
73  // (at 30fps), ~12kbps for CIF, 36kbps for VGA, 100kps for HD/720p.
74  // Also turn off at very small frame sizes, to avoid too large fraction of
75  // superblocks to be refreshed per frame. Threshold below is less than QCIF.
76  if (rc->avg_frame_bandwidth < factor * number_blocks ||
77      number_blocks / 64 < 5)
78    return 0;
79  else
80    return 1;
81}
82
83// Check if this coding block, of size bsize, should be considered for refresh
84// (lower-qp coding). Decision can be based on various factors, such as
85// size of the coding block (i.e., below min_block size rejected), coding
86// mode, and rate/distortion.
87static int candidate_refresh_aq(const CYCLIC_REFRESH *cr,
88                                const MB_MODE_INFO *mbmi,
89                                int64_t rate,
90                                int64_t dist,
91                                int bsize) {
92  MV mv = mbmi->mv[0].as_mv;
93  // Reject the block for lower-qp coding if projected distortion
94  // is above the threshold, and any of the following is true:
95  // 1) mode uses large mv
96  // 2) mode is an intra-mode
97  // Otherwise accept for refresh.
98  if (dist > cr->thresh_dist_sb &&
99      (mv.row > cr->motion_thresh || mv.row < -cr->motion_thresh ||
100       mv.col > cr->motion_thresh || mv.col < -cr->motion_thresh ||
101       !is_inter_block(mbmi)))
102    return CR_SEGMENT_ID_BASE;
103  else  if (bsize >= BLOCK_16X16 &&
104            rate < cr->thresh_rate_sb &&
105            is_inter_block(mbmi) &&
106            mbmi->mv[0].as_int == 0 &&
107            cr->rate_boost_fac > 10)
108    // More aggressive delta-q for bigger blocks with zero motion.
109    return CR_SEGMENT_ID_BOOST2;
110  else
111    return CR_SEGMENT_ID_BOOST1;
112}
113
114// Compute delta-q for the segment.
115static int compute_deltaq(const VP9_COMP *cpi, int q, double rate_factor) {
116  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
117  const RATE_CONTROL *const rc = &cpi->rc;
118  int deltaq = vp9_compute_qdelta_by_rate(rc, cpi->common.frame_type,
119                                          q, rate_factor,
120                                          cpi->common.bit_depth);
121  if ((-deltaq) > cr->max_qdelta_perc * q / 100) {
122    deltaq = -cr->max_qdelta_perc * q / 100;
123  }
124  return deltaq;
125}
126
127// For the just encoded frame, estimate the bits, incorporating the delta-q
128// from non-base segment. For now ignore effect of multiple segments
129// (with different delta-q). Note this function is called in the postencode
130// (called from rc_update_rate_correction_factors()).
131int vp9_cyclic_refresh_estimate_bits_at_q(const VP9_COMP *cpi,
132                                          double correction_factor) {
133  const VP9_COMMON *const cm = &cpi->common;
134  const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
135  int estimated_bits;
136  int mbs = cm->MBs;
137  int num8x8bl = mbs << 2;
138  // Weight for non-base segments: use actual number of blocks refreshed in
139  // previous/just encoded frame. Note number of blocks here is in 8x8 units.
140  double weight_segment1 = (double)cr->actual_num_seg1_blocks / num8x8bl;
141  double weight_segment2 = (double)cr->actual_num_seg2_blocks / num8x8bl;
142  // Take segment weighted average for estimated bits.
143  estimated_bits = (int)((1.0 - weight_segment1 - weight_segment2) *
144      vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex, mbs,
145                             correction_factor, cm->bit_depth) +
146                             weight_segment1 *
147      vp9_estimate_bits_at_q(cm->frame_type,
148                             cm->base_qindex + cr->qindex_delta[1], mbs,
149                             correction_factor, cm->bit_depth) +
150                             weight_segment2 *
151      vp9_estimate_bits_at_q(cm->frame_type,
152                             cm->base_qindex + cr->qindex_delta[2], mbs,
153                             correction_factor, cm->bit_depth));
154  return estimated_bits;
155}
156
157// Prior to encoding the frame, estimate the bits per mb, for a given q = i and
158// a corresponding delta-q (for segment 1). This function is called in the
159// rc_regulate_q() to set the base qp index.
160// Note: the segment map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or
161// to 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock, prior to encoding.
162int vp9_cyclic_refresh_rc_bits_per_mb(const VP9_COMP *cpi, int i,
163                                      double correction_factor) {
164  const VP9_COMMON *const cm = &cpi->common;
165  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
166  int bits_per_mb;
167  int num8x8bl = cm->MBs << 2;
168  // Weight for segment prior to encoding: take the average of the target
169  // number for the frame to be encoded and the actual from the previous frame.
170  int target_refresh = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;
171  double weight_segment = (double)((target_refresh +
172      cr->actual_num_seg1_blocks + cr->actual_num_seg2_blocks) >> 1) /
173      num8x8bl;
174  // Compute delta-q corresponding to qindex i.
175  int deltaq = compute_deltaq(cpi, i, cr->rate_ratio_qdelta);
176  // Take segment weighted average for bits per mb.
177  bits_per_mb = (int)((1.0 - weight_segment) *
178      vp9_rc_bits_per_mb(cm->frame_type, i, correction_factor, cm->bit_depth) +
179      weight_segment *
180      vp9_rc_bits_per_mb(cm->frame_type, i + deltaq, correction_factor,
181                         cm->bit_depth));
182  return bits_per_mb;
183}
184
185// Prior to coding a given prediction block, of size bsize at (mi_row, mi_col),
186// check if we should reset the segment_id, and update the cyclic_refresh map
187// and segmentation map.
188void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi,
189                                       MB_MODE_INFO *const mbmi,
190                                       int mi_row, int mi_col,
191                                       BLOCK_SIZE bsize,
192                                       int64_t rate,
193                                       int64_t dist,
194                                       int skip) {
195  const VP9_COMMON *const cm = &cpi->common;
196  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
197  const int bw = num_8x8_blocks_wide_lookup[bsize];
198  const int bh = num_8x8_blocks_high_lookup[bsize];
199  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);
200  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);
201  const int block_index = mi_row * cm->mi_cols + mi_col;
202  const int refresh_this_block = candidate_refresh_aq(cr, mbmi, rate, dist,
203                                                      bsize);
204  // Default is to not update the refresh map.
205  int new_map_value = cr->map[block_index];
206  int x = 0; int y = 0;
207
208  // If this block is labeled for refresh, check if we should reset the
209  // segment_id.
210  if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {
211    mbmi->segment_id = refresh_this_block;
212    // Reset segment_id if it will be skipped.
213    if (skip)
214      mbmi->segment_id = CR_SEGMENT_ID_BASE;
215  }
216
217  // Update the cyclic refresh map, to be used for setting segmentation map
218  // for the next frame. If the block  will be refreshed this frame, mark it
219  // as clean. The magnitude of the -ve influences how long before we consider
220  // it for refresh again.
221  if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {
222    new_map_value = -cr->time_for_refresh;
223  } else if (refresh_this_block) {
224    // Else if it is accepted as candidate for refresh, and has not already
225    // been refreshed (marked as 1) then mark it as a candidate for cleanup
226    // for future time (marked as 0), otherwise don't update it.
227    if (cr->map[block_index] == 1)
228      new_map_value = 0;
229  } else {
230    // Leave it marked as block that is not candidate for refresh.
231    new_map_value = 1;
232  }
233
234  // Update entries in the cyclic refresh map with new_map_value, and
235  // copy mbmi->segment_id into global segmentation map.
236  for (y = 0; y < ymis; y++)
237    for (x = 0; x < xmis; x++) {
238      int map_offset = block_index + y * cm->mi_cols + x;
239      cr->map[map_offset] = new_map_value;
240      cpi->segmentation_map[map_offset] = mbmi->segment_id;
241    }
242}
243
244void vp9_cyclic_refresh_update_sb_postencode(VP9_COMP *const cpi,
245                                             const MB_MODE_INFO *const mbmi,
246                                             int mi_row, int mi_col,
247                                             BLOCK_SIZE bsize) {
248  const VP9_COMMON *const cm = &cpi->common;
249  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
250  MV mv = mbmi->mv[0].as_mv;
251  const int bw = num_8x8_blocks_wide_lookup[bsize];
252  const int bh = num_8x8_blocks_high_lookup[bsize];
253  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);
254  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);
255  const int block_index = mi_row * cm->mi_cols + mi_col;
256  int x, y;
257  for (y = 0; y < ymis; y++)
258    for (x = 0; x < xmis; x++) {
259      int map_offset = block_index + y * cm->mi_cols + x;
260      // Inter skip blocks were clearly not coded at the current qindex, so
261      // don't update the map for them. For cases where motion is non-zero or
262      // the reference frame isn't the previous frame, the previous value in
263      // the map for this spatial location is not entirely correct.
264      if ((!is_inter_block(mbmi) || !mbmi->skip) &&
265          mbmi->segment_id <= CR_SEGMENT_ID_BOOST2) {
266        cr->last_coded_q_map[map_offset] = clamp(
267            cm->base_qindex + cr->qindex_delta[mbmi->segment_id], 0, MAXQ);
268      } else if (is_inter_block(mbmi) && mbmi->skip &&
269                 mbmi->segment_id <= CR_SEGMENT_ID_BOOST2) {
270        cr->last_coded_q_map[map_offset] = VPXMIN(
271            clamp(cm->base_qindex + cr->qindex_delta[mbmi->segment_id],
272                  0, MAXQ),
273            cr->last_coded_q_map[map_offset]);
274      // Update the consecutive zero/low_mv count.
275      if (is_inter_block(mbmi) && (abs(mv.row) < 8 && abs(mv.col) < 8)) {
276        if (cr->consec_zero_mv[map_offset] < 255)
277          cr->consec_zero_mv[map_offset]++;
278      } else {
279        cr->consec_zero_mv[map_offset] = 0;
280      }
281    }
282  }
283}
284
285// Update the actual number of blocks that were applied the segment delta q.
286void vp9_cyclic_refresh_postencode(VP9_COMP *const cpi) {
287  VP9_COMMON *const cm = &cpi->common;
288  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
289  unsigned char *const seg_map = cpi->segmentation_map;
290  int mi_row, mi_col;
291  cr->actual_num_seg1_blocks = 0;
292  cr->actual_num_seg2_blocks = 0;
293  for (mi_row = 0; mi_row < cm->mi_rows; mi_row++)
294    for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {
295      if (cyclic_refresh_segment_id(
296          seg_map[mi_row * cm->mi_cols + mi_col]) == CR_SEGMENT_ID_BOOST1)
297        cr->actual_num_seg1_blocks++;
298      else if (cyclic_refresh_segment_id(
299          seg_map[mi_row * cm->mi_cols + mi_col]) == CR_SEGMENT_ID_BOOST2)
300        cr->actual_num_seg2_blocks++;
301    }
302}
303
304// Set golden frame update interval, for non-svc 1 pass CBR mode.
305void vp9_cyclic_refresh_set_golden_update(VP9_COMP *const cpi) {
306  RATE_CONTROL *const rc = &cpi->rc;
307  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
308  // Set minimum gf_interval for GF update to a multiple (== 2) of refresh
309  // period. Depending on past encoding stats, GF flag may be reset and update
310  // may not occur until next baseline_gf_interval.
311  if (cr->percent_refresh > 0)
312    rc->baseline_gf_interval = 4 * (100 / cr->percent_refresh);
313  else
314    rc->baseline_gf_interval = 40;
315}
316
317// Update some encoding stats (from the just encoded frame). If this frame's
318// background has high motion, refresh the golden frame. Otherwise, if the
319// golden reference is to be updated check if we should NOT update the golden
320// ref.
321void vp9_cyclic_refresh_check_golden_update(VP9_COMP *const cpi) {
322  VP9_COMMON *const cm = &cpi->common;
323  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
324  int mi_row, mi_col;
325  double fraction_low = 0.0;
326  int low_content_frame = 0;
327
328  MODE_INFO **mi = cm->mi_grid_visible;
329  RATE_CONTROL *const rc = &cpi->rc;
330  const int rows = cm->mi_rows, cols = cm->mi_cols;
331  int cnt1 = 0, cnt2 = 0;
332  int force_gf_refresh = 0;
333
334  for (mi_row = 0; mi_row < rows; mi_row++) {
335    for (mi_col = 0; mi_col < cols; mi_col++) {
336      int16_t abs_mvr = mi[0]->mbmi.mv[0].as_mv.row >= 0 ?
337          mi[0]->mbmi.mv[0].as_mv.row : -1 * mi[0]->mbmi.mv[0].as_mv.row;
338      int16_t abs_mvc = mi[0]->mbmi.mv[0].as_mv.col >= 0 ?
339          mi[0]->mbmi.mv[0].as_mv.col : -1 * mi[0]->mbmi.mv[0].as_mv.col;
340
341      // Calculate the motion of the background.
342      if (abs_mvr <= 16 && abs_mvc <= 16) {
343        cnt1++;
344        if (abs_mvr == 0 && abs_mvc == 0)
345          cnt2++;
346      }
347      mi++;
348
349      // Accumulate low_content_frame.
350      if (cr->map[mi_row * cols + mi_col] < 1)
351        low_content_frame++;
352    }
353    mi += 8;
354  }
355
356  // For video conference clips, if the background has high motion in current
357  // frame because of the camera movement, set this frame as the golden frame.
358  // Use 70% and 5% as the thresholds for golden frame refreshing.
359  // Also, force this frame as a golden update frame if this frame will change
360  // the resolution (resize_pending != 0).
361  if (cpi->resize_pending != 0 ||
362     (cnt1 * 10 > (70 * rows * cols) && cnt2 * 20 < cnt1)) {
363    vp9_cyclic_refresh_set_golden_update(cpi);
364    rc->frames_till_gf_update_due = rc->baseline_gf_interval;
365
366    if (rc->frames_till_gf_update_due > rc->frames_to_key)
367      rc->frames_till_gf_update_due = rc->frames_to_key;
368    cpi->refresh_golden_frame = 1;
369    force_gf_refresh = 1;
370  }
371
372  fraction_low =
373      (double)low_content_frame / (rows * cols);
374  // Update average.
375  cr->low_content_avg = (fraction_low + 3 * cr->low_content_avg) / 4;
376  if (!force_gf_refresh && cpi->refresh_golden_frame == 1) {
377    // Don't update golden reference if the amount of low_content for the
378    // current encoded frame is small, or if the recursive average of the
379    // low_content over the update interval window falls below threshold.
380    if (fraction_low < 0.8 || cr->low_content_avg < 0.7)
381      cpi->refresh_golden_frame = 0;
382    // Reset for next internal.
383    cr->low_content_avg = fraction_low;
384  }
385}
386
387// Update the segmentation map, and related quantities: cyclic refresh map,
388// refresh sb_index, and target number of blocks to be refreshed.
389// The map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or to
390// 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock.
391// Blocks labeled as BOOST1 may later get set to BOOST2 (during the
392// encoding of the superblock).
393static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
394  VP9_COMMON *const cm = &cpi->common;
395  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
396  unsigned char *const seg_map = cpi->segmentation_map;
397  int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame;
398  int xmis, ymis, x, y;
399  int consec_zero_mv_thresh = 0;
400  int qindex_thresh = 0;
401  int count_sel = 0;
402  int count_tot = 0;
403  memset(seg_map, CR_SEGMENT_ID_BASE, cm->mi_rows * cm->mi_cols);
404  sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
405  sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
406  sbs_in_frame = sb_cols * sb_rows;
407  // Number of target blocks to get the q delta (segment 1).
408  block_count = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;
409  // Set the segmentation map: cycle through the superblocks, starting at
410  // cr->mb_index, and stopping when either block_count blocks have been found
411  // to be refreshed, or we have passed through whole frame.
412  assert(cr->sb_index < sbs_in_frame);
413  i = cr->sb_index;
414  cr->target_num_seg_blocks = 0;
415  if (cpi->oxcf.content != VP9E_CONTENT_SCREEN)
416    consec_zero_mv_thresh = 100;
417  qindex_thresh =
418      cpi->oxcf.content == VP9E_CONTENT_SCREEN
419      ? vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)
420      : vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST1, cm->base_qindex);
421  do {
422    int sum_map = 0;
423    // Get the mi_row/mi_col corresponding to superblock index i.
424    int sb_row_index = (i / sb_cols);
425    int sb_col_index = i - sb_row_index * sb_cols;
426    int mi_row = sb_row_index * MI_BLOCK_SIZE;
427    int mi_col = sb_col_index * MI_BLOCK_SIZE;
428    assert(mi_row >= 0 && mi_row < cm->mi_rows);
429    assert(mi_col >= 0 && mi_col < cm->mi_cols);
430    bl_index = mi_row * cm->mi_cols + mi_col;
431    // Loop through all 8x8 blocks in superblock and update map.
432    xmis =
433        VPXMIN(cm->mi_cols - mi_col, num_8x8_blocks_wide_lookup[BLOCK_64X64]);
434    ymis =
435        VPXMIN(cm->mi_rows - mi_row, num_8x8_blocks_high_lookup[BLOCK_64X64]);
436    for (y = 0; y < ymis; y++) {
437      for (x = 0; x < xmis; x++) {
438        const int bl_index2 = bl_index + y * cm->mi_cols + x;
439        // If the block is as a candidate for clean up then mark it
440        // for possible boost/refresh (segment 1). The segment id may get
441        // reset to 0 later if block gets coded anything other than ZEROMV.
442        if (cr->map[bl_index2] == 0) {
443          count_tot++;
444          if (cr->last_coded_q_map[bl_index2] > qindex_thresh ||
445              cr->consec_zero_mv[bl_index2] < consec_zero_mv_thresh) {
446            sum_map++;
447            count_sel++;
448          }
449        } else if (cr->map[bl_index2] < 0) {
450          cr->map[bl_index2]++;
451        }
452      }
453    }
454    // Enforce constant segment over superblock.
455    // If segment is at least half of superblock, set to 1.
456    if (sum_map >= xmis * ymis / 2) {
457      for (y = 0; y < ymis; y++)
458        for (x = 0; x < xmis; x++) {
459          seg_map[bl_index + y * cm->mi_cols + x] = CR_SEGMENT_ID_BOOST1;
460        }
461      cr->target_num_seg_blocks += xmis * ymis;
462    }
463    i++;
464    if (i == sbs_in_frame) {
465      i = 0;
466    }
467  } while (cr->target_num_seg_blocks < block_count && i != cr->sb_index);
468  cr->sb_index = i;
469  cr->reduce_refresh = 0;
470  if (count_sel < (3 * count_tot) >> 2)
471    cr->reduce_refresh = 1;
472}
473
474// Set cyclic refresh parameters.
475void vp9_cyclic_refresh_update_parameters(VP9_COMP *const cpi) {
476  const RATE_CONTROL *const rc = &cpi->rc;
477  const VP9_COMMON *const cm = &cpi->common;
478  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
479  cr->percent_refresh = 10;
480  if (cr->reduce_refresh)
481    cr->percent_refresh = 5;
482  cr->max_qdelta_perc = 50;
483  cr->time_for_refresh = 0;
484  // Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4)
485  // periods of the refresh cycle, after a key frame.
486  // Account for larger interval on base layer for temporal layers.
487  if (cr->percent_refresh > 0 &&
488      rc->frames_since_key <  (4 * cpi->svc.number_temporal_layers) *
489      (100 / cr->percent_refresh))
490    cr->rate_ratio_qdelta = 3.0;
491  else
492    cr->rate_ratio_qdelta = 2.0;
493  // Adjust some parameters for low resolutions at low bitrates.
494  if (cm->width <= 352 &&
495      cm->height <= 288 &&
496      rc->avg_frame_bandwidth < 3400) {
497    cr->motion_thresh = 4;
498    cr->rate_boost_fac = 10;
499  } else {
500    cr->motion_thresh = 32;
501    cr->rate_boost_fac = 15;
502  }
503  if (cpi->svc.spatial_layer_id > 0) {
504    cr->motion_thresh = 4;
505    cr->rate_boost_fac = 12;
506  }
507}
508
509// Setup cyclic background refresh: set delta q and segmentation map.
510void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
511  VP9_COMMON *const cm = &cpi->common;
512  const RATE_CONTROL *const rc = &cpi->rc;
513  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
514  struct segmentation *const seg = &cm->seg;
515  const int apply_cyclic_refresh  = apply_cyclic_refresh_bitrate(cm, rc);
516  if (cm->current_video_frame == 0)
517    cr->low_content_avg = 0.0;
518  // Don't apply refresh on key frame or temporal enhancement layer frames.
519  if (!apply_cyclic_refresh ||
520      (cm->frame_type == KEY_FRAME) ||
521      (cpi->svc.temporal_layer_id > 0)) {
522    // Set segmentation map to 0 and disable.
523    unsigned char *const seg_map = cpi->segmentation_map;
524    memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
525    vp9_disable_segmentation(&cm->seg);
526    if (cm->frame_type == KEY_FRAME) {
527      memset(cr->last_coded_q_map, MAXQ,
528             cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));
529      memset(cr->consec_zero_mv, 0,
530             cm->mi_rows * cm->mi_cols * sizeof(*cr->consec_zero_mv));
531      cr->sb_index = 0;
532    }
533    return;
534  } else {
535    int qindex_delta = 0;
536    int qindex2;
537    const double q = vp9_convert_qindex_to_q(cm->base_qindex, cm->bit_depth);
538    vpx_clear_system_state();
539    // Set rate threshold to some multiple (set to 2 for now) of the target
540    // rate (target is given by sb64_target_rate and scaled by 256).
541    cr->thresh_rate_sb = ((int64_t)(rc->sb64_target_rate) << 8) << 2;
542    // Distortion threshold, quadratic in Q, scale factor to be adjusted.
543    // q will not exceed 457, so (q * q) is within 32bit; see:
544    // vp9_convert_qindex_to_q(), vp9_ac_quant(), ac_qlookup*[].
545    cr->thresh_dist_sb = ((int64_t)(q * q)) << 2;
546
547    // Set up segmentation.
548    // Clear down the segment map.
549    vp9_enable_segmentation(&cm->seg);
550    vp9_clearall_segfeatures(seg);
551    // Select delta coding method.
552    seg->abs_delta = SEGMENT_DELTADATA;
553
554    // Note: setting temporal_update has no effect, as the seg-map coding method
555    // (temporal or spatial) is determined in vp9_choose_segmap_coding_method(),
556    // based on the coding cost of each method. For error_resilient mode on the
557    // last_frame_seg_map is set to 0, so if temporal coding is used, it is
558    // relative to 0 previous map.
559    // seg->temporal_update = 0;
560
561    // Segment BASE "Q" feature is disabled so it defaults to the baseline Q.
562    vp9_disable_segfeature(seg, CR_SEGMENT_ID_BASE, SEG_LVL_ALT_Q);
563    // Use segment BOOST1 for in-frame Q adjustment.
564    vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q);
565    // Use segment BOOST2 for more aggressive in-frame Q adjustment.
566    vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q);
567
568    // Set the q delta for segment BOOST1.
569    qindex_delta = compute_deltaq(cpi, cm->base_qindex, cr->rate_ratio_qdelta);
570    cr->qindex_delta[1] = qindex_delta;
571
572    // Compute rd-mult for segment BOOST1.
573    qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ);
574
575    cr->rdmult = vp9_compute_rd_mult(cpi, qindex2);
576
577    vp9_set_segdata(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q, qindex_delta);
578
579    // Set a more aggressive (higher) q delta for segment BOOST2.
580    qindex_delta = compute_deltaq(
581        cpi, cm->base_qindex,
582        VPXMIN(CR_MAX_RATE_TARGET_RATIO,
583               0.1 * cr->rate_boost_fac * cr->rate_ratio_qdelta));
584    cr->qindex_delta[2] = qindex_delta;
585    vp9_set_segdata(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q, qindex_delta);
586
587    // Reset if resoluton change has occurred.
588    if (cpi->resize_pending != 0)
589      vp9_cyclic_refresh_reset_resize(cpi);
590
591    // Update the segmentation and refresh map.
592    cyclic_refresh_update_map(cpi);
593  }
594}
595
596int vp9_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) {
597  return cr->rdmult;
598}
599
600void vp9_cyclic_refresh_reset_resize(VP9_COMP *const cpi) {
601  const VP9_COMMON *const cm = &cpi->common;
602  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
603  memset(cr->map, 0, cm->mi_rows * cm->mi_cols);
604  memset(cr->last_coded_q_map, MAXQ, cm->mi_rows * cm->mi_cols);
605  memset(cr->consec_zero_mv, 0, cm->mi_rows * cm->mi_cols);
606  cr->sb_index = 0;
607  cpi->refresh_golden_frame = 1;
608}
609