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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 
13 #include "vpx_mem/vpx_mem.h"
14 
15 #include "vp9/common/vp9_pred_common.h"
16 #include "vp9/common/vp9_tile_common.h"
17 
18 #include "vp9/encoder/vp9_cost.h"
19 #include "vp9/encoder/vp9_segmentation.h"
20 
vp9_enable_segmentation(struct segmentation * seg)21 void vp9_enable_segmentation(struct segmentation *seg) {
22   seg->enabled = 1;
23   seg->update_map = 1;
24   seg->update_data = 1;
25 }
26 
vp9_disable_segmentation(struct segmentation * seg)27 void vp9_disable_segmentation(struct segmentation *seg) {
28   seg->enabled = 0;
29   seg->update_map = 0;
30   seg->update_data = 0;
31 }
32 
vp9_set_segment_data(struct segmentation * seg,signed char * feature_data,unsigned char abs_delta)33 void vp9_set_segment_data(struct segmentation *seg, signed char *feature_data,
34                           unsigned char abs_delta) {
35   seg->abs_delta = abs_delta;
36 
37   memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
38 }
vp9_disable_segfeature(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)39 void vp9_disable_segfeature(struct segmentation *seg, int segment_id,
40                             SEG_LVL_FEATURES feature_id) {
41   seg->feature_mask[segment_id] &= ~(1 << feature_id);
42 }
43 
vp9_clear_segdata(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)44 void vp9_clear_segdata(struct segmentation *seg, int segment_id,
45                        SEG_LVL_FEATURES feature_id) {
46   seg->feature_data[segment_id][feature_id] = 0;
47 }
48 
vp9_psnr_aq_mode_setup(struct segmentation * seg)49 void vp9_psnr_aq_mode_setup(struct segmentation *seg) {
50   int i;
51 
52   vp9_enable_segmentation(seg);
53   vp9_clearall_segfeatures(seg);
54   seg->abs_delta = SEGMENT_DELTADATA;
55 
56   for (i = 0; i < MAX_SEGMENTS; ++i) {
57     vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, 2 * (i - (MAX_SEGMENTS / 2)));
58     vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
59   }
60 }
61 
62 // Based on set of segment counts calculate a probability tree
calc_segtree_probs(int * segcounts,vpx_prob * segment_tree_probs)63 static void calc_segtree_probs(int *segcounts, vpx_prob *segment_tree_probs) {
64   // Work out probabilities of each segment
65   const int c01 = segcounts[0] + segcounts[1];
66   const int c23 = segcounts[2] + segcounts[3];
67   const int c45 = segcounts[4] + segcounts[5];
68   const int c67 = segcounts[6] + segcounts[7];
69 
70   segment_tree_probs[0] = get_binary_prob(c01 + c23, c45 + c67);
71   segment_tree_probs[1] = get_binary_prob(c01, c23);
72   segment_tree_probs[2] = get_binary_prob(c45, c67);
73   segment_tree_probs[3] = get_binary_prob(segcounts[0], segcounts[1]);
74   segment_tree_probs[4] = get_binary_prob(segcounts[2], segcounts[3]);
75   segment_tree_probs[5] = get_binary_prob(segcounts[4], segcounts[5]);
76   segment_tree_probs[6] = get_binary_prob(segcounts[6], segcounts[7]);
77 }
78 
79 // Based on set of segment counts and probabilities calculate a cost estimate
cost_segmap(int * segcounts,vpx_prob * probs)80 static int cost_segmap(int *segcounts, vpx_prob *probs) {
81   const int c01 = segcounts[0] + segcounts[1];
82   const int c23 = segcounts[2] + segcounts[3];
83   const int c45 = segcounts[4] + segcounts[5];
84   const int c67 = segcounts[6] + segcounts[7];
85   const int c0123 = c01 + c23;
86   const int c4567 = c45 + c67;
87 
88   // Cost the top node of the tree
89   int cost = c0123 * vp9_cost_zero(probs[0]) + c4567 * vp9_cost_one(probs[0]);
90 
91   // Cost subsequent levels
92   if (c0123 > 0) {
93     cost += c01 * vp9_cost_zero(probs[1]) + c23 * vp9_cost_one(probs[1]);
94 
95     if (c01 > 0)
96       cost += segcounts[0] * vp9_cost_zero(probs[3]) +
97               segcounts[1] * vp9_cost_one(probs[3]);
98     if (c23 > 0)
99       cost += segcounts[2] * vp9_cost_zero(probs[4]) +
100               segcounts[3] * vp9_cost_one(probs[4]);
101   }
102 
103   if (c4567 > 0) {
104     cost += c45 * vp9_cost_zero(probs[2]) + c67 * vp9_cost_one(probs[2]);
105 
106     if (c45 > 0)
107       cost += segcounts[4] * vp9_cost_zero(probs[5]) +
108               segcounts[5] * vp9_cost_one(probs[5]);
109     if (c67 > 0)
110       cost += segcounts[6] * vp9_cost_zero(probs[6]) +
111               segcounts[7] * vp9_cost_one(probs[6]);
112   }
113 
114   return cost;
115 }
116 
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)117 static void count_segs(const VP9_COMMON *cm, MACROBLOCKD *xd,
118                        const TileInfo *tile, MODE_INFO **mi,
119                        int *no_pred_segcounts,
120                        int (*temporal_predictor_count)[2],
121                        int *t_unpred_seg_counts, int bw, int bh, int mi_row,
122                        int mi_col) {
123   int segment_id;
124 
125   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
126 
127   xd->mi = mi;
128   segment_id = xd->mi[0]->segment_id;
129 
130   set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
131 
132   // Count the number of hits on each segment with no prediction
133   no_pred_segcounts[segment_id]++;
134 
135   // Temporal prediction not allowed on key frames
136   if (cm->frame_type != KEY_FRAME) {
137     const BLOCK_SIZE bsize = xd->mi[0]->sb_type;
138     // Test to see if the segment id matches the predicted value.
139     const int pred_segment_id =
140         get_segment_id(cm, cm->last_frame_seg_map, bsize, mi_row, mi_col);
141     const int pred_flag = pred_segment_id == segment_id;
142     const int pred_context = vp9_get_pred_context_seg_id(xd);
143 
144     // Store the prediction status for this mb and update counts
145     // as appropriate
146     xd->mi[0]->seg_id_predicted = pred_flag;
147     temporal_predictor_count[pred_context][pred_flag]++;
148 
149     // Update the "unpredicted" segment count
150     if (!pred_flag) t_unpred_seg_counts[segment_id]++;
151   }
152 }
153 
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)154 static void count_segs_sb(const VP9_COMMON *cm, MACROBLOCKD *xd,
155                           const TileInfo *tile, MODE_INFO **mi,
156                           int *no_pred_segcounts,
157                           int (*temporal_predictor_count)[2],
158                           int *t_unpred_seg_counts, int mi_row, int mi_col,
159                           BLOCK_SIZE bsize) {
160   const int mis = cm->mi_stride;
161   int bw, bh;
162   const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
163 
164   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
165 
166   bw = num_8x8_blocks_wide_lookup[mi[0]->sb_type];
167   bh = num_8x8_blocks_high_lookup[mi[0]->sb_type];
168 
169   if (bw == bs && bh == bs) {
170     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
171                t_unpred_seg_counts, bs, bs, mi_row, mi_col);
172   } else if (bw == bs && bh < bs) {
173     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
174                t_unpred_seg_counts, bs, hbs, mi_row, mi_col);
175     count_segs(cm, xd, tile, mi + hbs * mis, no_pred_segcounts,
176                temporal_predictor_count, t_unpred_seg_counts, bs, hbs,
177                mi_row + hbs, mi_col);
178   } else if (bw < bs && bh == bs) {
179     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
180                t_unpred_seg_counts, hbs, bs, mi_row, mi_col);
181     count_segs(cm, xd, tile, mi + hbs, no_pred_segcounts,
182                temporal_predictor_count, t_unpred_seg_counts, hbs, bs, mi_row,
183                mi_col + hbs);
184   } else {
185     const BLOCK_SIZE subsize = subsize_lookup[PARTITION_SPLIT][bsize];
186     int n;
187 
188     assert(bw < bs && bh < bs);
189 
190     for (n = 0; n < 4; n++) {
191       const int mi_dc = hbs * (n & 1);
192       const int mi_dr = hbs * (n >> 1);
193 
194       count_segs_sb(cm, xd, tile, &mi[mi_dr * mis + mi_dc], no_pred_segcounts,
195                     temporal_predictor_count, t_unpred_seg_counts,
196                     mi_row + mi_dr, mi_col + mi_dc, subsize);
197     }
198   }
199 }
200 
vp9_choose_segmap_coding_method(VP9_COMMON * cm,MACROBLOCKD * xd)201 void vp9_choose_segmap_coding_method(VP9_COMMON *cm, MACROBLOCKD *xd) {
202   struct segmentation *seg = &cm->seg;
203 
204   int no_pred_cost;
205   int t_pred_cost = INT_MAX;
206 
207   int i, tile_col, mi_row, mi_col;
208 
209   int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
210   int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
211   int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
212 
213   vpx_prob no_pred_tree[SEG_TREE_PROBS];
214   vpx_prob t_pred_tree[SEG_TREE_PROBS];
215   vpx_prob t_nopred_prob[PREDICTION_PROBS];
216 
217   // Set default state for the segment tree probabilities and the
218   // temporal coding probabilities
219   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
220   memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
221 
222   // First of all generate stats regarding how well the last segment map
223   // predicts this one
224   for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
225     TileInfo tile;
226     MODE_INFO **mi_ptr;
227     vp9_tile_init(&tile, cm, 0, tile_col);
228 
229     mi_ptr = cm->mi_grid_visible + tile.mi_col_start;
230     for (mi_row = 0; mi_row < cm->mi_rows;
231          mi_row += 8, mi_ptr += 8 * cm->mi_stride) {
232       MODE_INFO **mi = mi_ptr;
233       for (mi_col = tile.mi_col_start; mi_col < tile.mi_col_end;
234            mi_col += 8, mi += 8)
235         count_segs_sb(cm, xd, &tile, mi, no_pred_segcounts,
236                       temporal_predictor_count, t_unpred_seg_counts, mi_row,
237                       mi_col, BLOCK_64X64);
238     }
239   }
240 
241   // Work out probability tree for coding segments without prediction
242   // and the cost.
243   calc_segtree_probs(no_pred_segcounts, no_pred_tree);
244   no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
245 
246   // Key frames cannot use temporal prediction
247   if (!frame_is_intra_only(cm)) {
248     // Work out probability tree for coding those segments not
249     // predicted using the temporal method and the cost.
250     calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
251     t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
252 
253     // Add in the cost of the signaling for each prediction context.
254     for (i = 0; i < PREDICTION_PROBS; i++) {
255       const int count0 = temporal_predictor_count[i][0];
256       const int count1 = temporal_predictor_count[i][1];
257 
258       t_nopred_prob[i] = get_binary_prob(count0, count1);
259 
260       // Add in the predictor signaling cost
261       t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
262                      count1 * vp9_cost_one(t_nopred_prob[i]);
263     }
264   }
265 
266   // Now choose which coding method to use.
267   if (t_pred_cost < no_pred_cost) {
268     seg->temporal_update = 1;
269     memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
270     memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
271   } else {
272     seg->temporal_update = 0;
273     memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
274   }
275 }
276 
vp9_reset_segment_features(struct segmentation * seg)277 void vp9_reset_segment_features(struct segmentation *seg) {
278   // Set up default state for MB feature flags
279   seg->enabled = 0;
280   seg->update_map = 0;
281   seg->update_data = 0;
282   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
283   vp9_clearall_segfeatures(seg);
284 }
285