1 /*
2  *  Copyright (c) 2012 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_mem/vpx_mem.h"
15 
16 #include "vp9/common/vp9_pred_common.h"
17 #include "vp9/common/vp9_tile_common.h"
18 
19 #include "vp9/encoder/vp9_cost.h"
20 #include "vp9/encoder/vp9_segmentation.h"
21 
vp9_enable_segmentation(struct segmentation * seg)22 void vp9_enable_segmentation(struct segmentation *seg) {
23   seg->enabled = 1;
24   seg->update_map = 1;
25   seg->update_data = 1;
26 }
27 
vp9_disable_segmentation(struct segmentation * seg)28 void vp9_disable_segmentation(struct segmentation *seg) {
29   seg->enabled = 0;
30   seg->update_map = 0;
31   seg->update_data = 0;
32 }
33 
vp9_set_segment_data(struct segmentation * seg,signed char * feature_data,unsigned char abs_delta)34 void vp9_set_segment_data(struct segmentation *seg, signed char *feature_data,
35                           unsigned char abs_delta) {
36   seg->abs_delta = abs_delta;
37 
38   memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
39 }
vp9_disable_segfeature(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)40 void vp9_disable_segfeature(struct segmentation *seg, int segment_id,
41                             SEG_LVL_FEATURES feature_id) {
42   seg->feature_mask[segment_id] &= ~(1 << feature_id);
43 }
44 
vp9_clear_segdata(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)45 void vp9_clear_segdata(struct segmentation *seg, int segment_id,
46                        SEG_LVL_FEATURES feature_id) {
47   seg->feature_data[segment_id][feature_id] = 0;
48 }
49 
vp9_psnr_aq_mode_setup(struct segmentation * seg)50 void vp9_psnr_aq_mode_setup(struct segmentation *seg) {
51   int i;
52 
53   vp9_enable_segmentation(seg);
54   vp9_clearall_segfeatures(seg);
55   seg->abs_delta = SEGMENT_DELTADATA;
56 
57   for (i = 0; i < MAX_SEGMENTS; ++i) {
58     vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, 2 * (i - (MAX_SEGMENTS / 2)));
59     vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
60   }
61 }
62 
vp9_perceptual_aq_mode_setup(struct VP9_COMP * cpi,struct segmentation * seg)63 void vp9_perceptual_aq_mode_setup(struct VP9_COMP *cpi,
64                                   struct segmentation *seg) {
65   const VP9_COMMON *cm = &cpi->common;
66   const int seg_counts = cpi->kmeans_ctr_num;
67   const int base_qindex = cm->base_qindex;
68   const double base_qstep = vp9_convert_qindex_to_q(base_qindex, cm->bit_depth);
69   const double mid_ctr = cpi->kmeans_ctr_ls[seg_counts / 2];
70   const double var_diff_scale = 4.0;
71   int i;
72 
73   assert(seg_counts <= MAX_SEGMENTS);
74 
75   vp9_enable_segmentation(seg);
76   vp9_clearall_segfeatures(seg);
77   seg->abs_delta = SEGMENT_DELTADATA;
78 
79   for (i = 0; i < seg_counts / 2; ++i) {
80     double wiener_var_diff = mid_ctr - cpi->kmeans_ctr_ls[i];
81     double target_qstep = base_qstep / (1.0 + wiener_var_diff / var_diff_scale);
82     int target_qindex = vp9_convert_q_to_qindex(target_qstep, cm->bit_depth);
83     assert(wiener_var_diff >= 0.0);
84 
85     vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, target_qindex - base_qindex);
86     vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
87   }
88 
89   vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, 0);
90   vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
91 
92   for (; i < seg_counts; ++i) {
93     double wiener_var_diff = cpi->kmeans_ctr_ls[i] - mid_ctr;
94     double target_qstep = base_qstep * (1.0 + wiener_var_diff / var_diff_scale);
95     int target_qindex = vp9_convert_q_to_qindex(target_qstep, cm->bit_depth);
96     assert(wiener_var_diff >= 0.0);
97 
98     vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, target_qindex - base_qindex);
99     vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
100   }
101 }
102 
103 // Based on set of segment counts calculate a probability tree
calc_segtree_probs(int * segcounts,vpx_prob * segment_tree_probs)104 static void calc_segtree_probs(int *segcounts, vpx_prob *segment_tree_probs) {
105   // Work out probabilities of each segment
106   const int c01 = segcounts[0] + segcounts[1];
107   const int c23 = segcounts[2] + segcounts[3];
108   const int c45 = segcounts[4] + segcounts[5];
109   const int c67 = segcounts[6] + segcounts[7];
110 
111   segment_tree_probs[0] = get_binary_prob(c01 + c23, c45 + c67);
112   segment_tree_probs[1] = get_binary_prob(c01, c23);
113   segment_tree_probs[2] = get_binary_prob(c45, c67);
114   segment_tree_probs[3] = get_binary_prob(segcounts[0], segcounts[1]);
115   segment_tree_probs[4] = get_binary_prob(segcounts[2], segcounts[3]);
116   segment_tree_probs[5] = get_binary_prob(segcounts[4], segcounts[5]);
117   segment_tree_probs[6] = get_binary_prob(segcounts[6], segcounts[7]);
118 }
119 
120 // Based on set of segment counts and probabilities calculate a cost estimate
cost_segmap(int * segcounts,vpx_prob * probs)121 static int cost_segmap(int *segcounts, vpx_prob *probs) {
122   const int c01 = segcounts[0] + segcounts[1];
123   const int c23 = segcounts[2] + segcounts[3];
124   const int c45 = segcounts[4] + segcounts[5];
125   const int c67 = segcounts[6] + segcounts[7];
126   const int c0123 = c01 + c23;
127   const int c4567 = c45 + c67;
128 
129   // Cost the top node of the tree
130   int cost = c0123 * vp9_cost_zero(probs[0]) + c4567 * vp9_cost_one(probs[0]);
131 
132   // Cost subsequent levels
133   if (c0123 > 0) {
134     cost += c01 * vp9_cost_zero(probs[1]) + c23 * vp9_cost_one(probs[1]);
135 
136     if (c01 > 0)
137       cost += segcounts[0] * vp9_cost_zero(probs[3]) +
138               segcounts[1] * vp9_cost_one(probs[3]);
139     if (c23 > 0)
140       cost += segcounts[2] * vp9_cost_zero(probs[4]) +
141               segcounts[3] * vp9_cost_one(probs[4]);
142   }
143 
144   if (c4567 > 0) {
145     cost += c45 * vp9_cost_zero(probs[2]) + c67 * vp9_cost_one(probs[2]);
146 
147     if (c45 > 0)
148       cost += segcounts[4] * vp9_cost_zero(probs[5]) +
149               segcounts[5] * vp9_cost_one(probs[5]);
150     if (c67 > 0)
151       cost += segcounts[6] * vp9_cost_zero(probs[6]) +
152               segcounts[7] * vp9_cost_one(probs[6]);
153   }
154 
155   return cost;
156 }
157 
count_segs(const VP9_COMMON * cm,MACROBLOCKD * xd,const TileInfo * tile,MODE_INFO ** mi,int * no_pred_segcounts,int (* temporal_predictor_count)[2],int * t_unpred_seg_counts,int bw,int bh,int mi_row,int mi_col)158 static void count_segs(const VP9_COMMON *cm, MACROBLOCKD *xd,
159                        const TileInfo *tile, MODE_INFO **mi,
160                        int *no_pred_segcounts,
161                        int (*temporal_predictor_count)[2],
162                        int *t_unpred_seg_counts, int bw, int bh, int mi_row,
163                        int mi_col) {
164   int segment_id;
165 
166   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
167 
168   xd->mi = mi;
169   segment_id = xd->mi[0]->segment_id;
170 
171   set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
172 
173   // Count the number of hits on each segment with no prediction
174   no_pred_segcounts[segment_id]++;
175 
176   // Temporal prediction not allowed on key frames
177   if (cm->frame_type != KEY_FRAME) {
178     const BLOCK_SIZE bsize = xd->mi[0]->sb_type;
179     // Test to see if the segment id matches the predicted value.
180     const int pred_segment_id =
181         get_segment_id(cm, cm->last_frame_seg_map, bsize, mi_row, mi_col);
182     const int pred_flag = pred_segment_id == segment_id;
183     const int pred_context = vp9_get_pred_context_seg_id(xd);
184 
185     // Store the prediction status for this mb and update counts
186     // as appropriate
187     xd->mi[0]->seg_id_predicted = pred_flag;
188     temporal_predictor_count[pred_context][pred_flag]++;
189 
190     // Update the "unpredicted" segment count
191     if (!pred_flag) t_unpred_seg_counts[segment_id]++;
192   }
193 }
194 
count_segs_sb(const VP9_COMMON * cm,MACROBLOCKD * xd,const TileInfo * tile,MODE_INFO ** mi,int * no_pred_segcounts,int (* temporal_predictor_count)[2],int * t_unpred_seg_counts,int mi_row,int mi_col,BLOCK_SIZE bsize)195 static void count_segs_sb(const VP9_COMMON *cm, MACROBLOCKD *xd,
196                           const TileInfo *tile, MODE_INFO **mi,
197                           int *no_pred_segcounts,
198                           int (*temporal_predictor_count)[2],
199                           int *t_unpred_seg_counts, int mi_row, int mi_col,
200                           BLOCK_SIZE bsize) {
201   const int mis = cm->mi_stride;
202   int bw, bh;
203   const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
204 
205   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
206 
207   bw = num_8x8_blocks_wide_lookup[mi[0]->sb_type];
208   bh = num_8x8_blocks_high_lookup[mi[0]->sb_type];
209 
210   if (bw == bs && bh == bs) {
211     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
212                t_unpred_seg_counts, bs, bs, mi_row, mi_col);
213   } else if (bw == bs && bh < bs) {
214     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
215                t_unpred_seg_counts, bs, hbs, mi_row, mi_col);
216     count_segs(cm, xd, tile, mi + hbs * mis, no_pred_segcounts,
217                temporal_predictor_count, t_unpred_seg_counts, bs, hbs,
218                mi_row + hbs, mi_col);
219   } else if (bw < bs && bh == bs) {
220     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
221                t_unpred_seg_counts, hbs, bs, mi_row, mi_col);
222     count_segs(cm, xd, tile, mi + hbs, no_pred_segcounts,
223                temporal_predictor_count, t_unpred_seg_counts, hbs, bs, mi_row,
224                mi_col + hbs);
225   } else {
226     const BLOCK_SIZE subsize = subsize_lookup[PARTITION_SPLIT][bsize];
227     int n;
228 
229     assert(bw < bs && bh < bs);
230 
231     for (n = 0; n < 4; n++) {
232       const int mi_dc = hbs * (n & 1);
233       const int mi_dr = hbs * (n >> 1);
234 
235       count_segs_sb(cm, xd, tile, &mi[mi_dr * mis + mi_dc], no_pred_segcounts,
236                     temporal_predictor_count, t_unpred_seg_counts,
237                     mi_row + mi_dr, mi_col + mi_dc, subsize);
238     }
239   }
240 }
241 
vp9_choose_segmap_coding_method(VP9_COMMON * cm,MACROBLOCKD * xd)242 void vp9_choose_segmap_coding_method(VP9_COMMON *cm, MACROBLOCKD *xd) {
243   struct segmentation *seg = &cm->seg;
244 
245   int no_pred_cost;
246   int t_pred_cost = INT_MAX;
247 
248   int i, tile_col, mi_row, mi_col;
249 
250   int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
251   int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
252   int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
253 
254   vpx_prob no_pred_tree[SEG_TREE_PROBS];
255   vpx_prob t_pred_tree[SEG_TREE_PROBS];
256   vpx_prob t_nopred_prob[PREDICTION_PROBS];
257 
258   // Set default state for the segment tree probabilities and the
259   // temporal coding probabilities
260   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
261   memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
262 
263   // First of all generate stats regarding how well the last segment map
264   // predicts this one
265   for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
266     TileInfo tile;
267     MODE_INFO **mi_ptr;
268     vp9_tile_init(&tile, cm, 0, tile_col);
269 
270     mi_ptr = cm->mi_grid_visible + tile.mi_col_start;
271     for (mi_row = 0; mi_row < cm->mi_rows;
272          mi_row += 8, mi_ptr += 8 * cm->mi_stride) {
273       MODE_INFO **mi = mi_ptr;
274       for (mi_col = tile.mi_col_start; mi_col < tile.mi_col_end;
275            mi_col += 8, mi += 8)
276         count_segs_sb(cm, xd, &tile, mi, no_pred_segcounts,
277                       temporal_predictor_count, t_unpred_seg_counts, mi_row,
278                       mi_col, BLOCK_64X64);
279     }
280   }
281 
282   // Work out probability tree for coding segments without prediction
283   // and the cost.
284   calc_segtree_probs(no_pred_segcounts, no_pred_tree);
285   no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
286 
287   // Key frames cannot use temporal prediction
288   if (!frame_is_intra_only(cm)) {
289     // Work out probability tree for coding those segments not
290     // predicted using the temporal method and the cost.
291     calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
292     t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
293 
294     // Add in the cost of the signaling for each prediction context.
295     for (i = 0; i < PREDICTION_PROBS; i++) {
296       const int count0 = temporal_predictor_count[i][0];
297       const int count1 = temporal_predictor_count[i][1];
298 
299       t_nopred_prob[i] = get_binary_prob(count0, count1);
300 
301       // Add in the predictor signaling cost
302       t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
303                      count1 * vp9_cost_one(t_nopred_prob[i]);
304     }
305   }
306 
307   // Now choose which coding method to use.
308   if (t_pred_cost < no_pred_cost) {
309     seg->temporal_update = 1;
310     memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
311     memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
312   } else {
313     seg->temporal_update = 0;
314     memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
315   }
316 }
317 
vp9_reset_segment_features(struct segmentation * seg)318 void vp9_reset_segment_features(struct segmentation *seg) {
319   // Set up default state for MB feature flags
320   seg->enabled = 0;
321   seg->update_map = 0;
322   seg->update_data = 0;
323   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
324   vp9_clearall_segfeatures(seg);
325 }
326