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 
12 #include <limits.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,
35                           signed char *feature_data,
36                           unsigned char abs_delta) {
37   seg->abs_delta = abs_delta;
38 
39   vpx_memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
40 
41   // TBD ?? Set the feature mask
42   // vpx_memcpy(cpi->mb.e_mbd.segment_feature_mask, 0,
43   //            sizeof(cpi->mb.e_mbd.segment_feature_mask));
44 }
vp9_disable_segfeature(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)45 void vp9_disable_segfeature(struct segmentation *seg, int segment_id,
46                             SEG_LVL_FEATURES feature_id) {
47   seg->feature_mask[segment_id] &= ~(1 << feature_id);
48 }
49 
vp9_clear_segdata(struct segmentation * seg,int segment_id,SEG_LVL_FEATURES feature_id)50 void vp9_clear_segdata(struct segmentation *seg, int segment_id,
51                        SEG_LVL_FEATURES feature_id) {
52   seg->feature_data[segment_id][feature_id] = 0;
53 }
54 
55 // Based on set of segment counts calculate a probability tree
calc_segtree_probs(int * segcounts,vp9_prob * segment_tree_probs)56 static void calc_segtree_probs(int *segcounts, vp9_prob *segment_tree_probs) {
57   // Work out probabilities of each segment
58   const int c01 = segcounts[0] + segcounts[1];
59   const int c23 = segcounts[2] + segcounts[3];
60   const int c45 = segcounts[4] + segcounts[5];
61   const int c67 = segcounts[6] + segcounts[7];
62 
63   segment_tree_probs[0] = get_binary_prob(c01 + c23, c45 + c67);
64   segment_tree_probs[1] = get_binary_prob(c01, c23);
65   segment_tree_probs[2] = get_binary_prob(c45, c67);
66   segment_tree_probs[3] = get_binary_prob(segcounts[0], segcounts[1]);
67   segment_tree_probs[4] = get_binary_prob(segcounts[2], segcounts[3]);
68   segment_tree_probs[5] = get_binary_prob(segcounts[4], segcounts[5]);
69   segment_tree_probs[6] = get_binary_prob(segcounts[6], segcounts[7]);
70 }
71 
72 // Based on set of segment counts and probabilities calculate a cost estimate
cost_segmap(int * segcounts,vp9_prob * probs)73 static int cost_segmap(int *segcounts, vp9_prob *probs) {
74   const int c01 = segcounts[0] + segcounts[1];
75   const int c23 = segcounts[2] + segcounts[3];
76   const int c45 = segcounts[4] + segcounts[5];
77   const int c67 = segcounts[6] + segcounts[7];
78   const int c0123 = c01 + c23;
79   const int c4567 = c45 + c67;
80 
81   // Cost the top node of the tree
82   int cost = c0123 * vp9_cost_zero(probs[0]) +
83              c4567 * vp9_cost_one(probs[0]);
84 
85   // Cost subsequent levels
86   if (c0123 > 0) {
87     cost += c01 * vp9_cost_zero(probs[1]) +
88             c23 * vp9_cost_one(probs[1]);
89 
90     if (c01 > 0)
91       cost += segcounts[0] * vp9_cost_zero(probs[3]) +
92               segcounts[1] * vp9_cost_one(probs[3]);
93     if (c23 > 0)
94       cost += segcounts[2] * vp9_cost_zero(probs[4]) +
95               segcounts[3] * vp9_cost_one(probs[4]);
96   }
97 
98   if (c4567 > 0) {
99     cost += c45 * vp9_cost_zero(probs[2]) +
100             c67 * vp9_cost_one(probs[2]);
101 
102     if (c45 > 0)
103       cost += segcounts[4] * vp9_cost_zero(probs[5]) +
104               segcounts[5] * vp9_cost_one(probs[5]);
105     if (c67 > 0)
106       cost += segcounts[6] * vp9_cost_zero(probs[6]) +
107               segcounts[7] * vp9_cost_one(probs[6]);
108   }
109 
110   return cost;
111 }
112 
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)113 static void count_segs(const VP9_COMMON *cm, MACROBLOCKD *xd,
114                        const TileInfo *tile, MODE_INFO **mi,
115                        int *no_pred_segcounts,
116                        int (*temporal_predictor_count)[2],
117                        int *t_unpred_seg_counts,
118                        int bw, int bh, int mi_row, int mi_col) {
119   int segment_id;
120 
121   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
122     return;
123 
124   xd->mi = mi;
125   segment_id = xd->mi[0]->mbmi.segment_id;
126 
127   set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
128 
129   // Count the number of hits on each segment with no prediction
130   no_pred_segcounts[segment_id]++;
131 
132   // Temporal prediction not allowed on key frames
133   if (cm->frame_type != KEY_FRAME) {
134     const BLOCK_SIZE bsize = xd->mi[0]->mbmi.sb_type;
135     // Test to see if the segment id matches the predicted value.
136     const int pred_segment_id = vp9_get_segment_id(cm, cm->last_frame_seg_map,
137                                                    bsize, mi_row, mi_col);
138     const int pred_flag = pred_segment_id == segment_id;
139     const int pred_context = vp9_get_pred_context_seg_id(xd);
140 
141     // Store the prediction status for this mb and update counts
142     // as appropriate
143     xd->mi[0]->mbmi.seg_id_predicted = pred_flag;
144     temporal_predictor_count[pred_context][pred_flag]++;
145 
146     // Update the "unpredicted" segment count
147     if (!pred_flag)
148       t_unpred_seg_counts[segment_id]++;
149   }
150 }
151 
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)152 static void count_segs_sb(const VP9_COMMON *cm, MACROBLOCKD *xd,
153                           const TileInfo *tile, MODE_INFO **mi,
154                           int *no_pred_segcounts,
155                           int (*temporal_predictor_count)[2],
156                           int *t_unpred_seg_counts,
157                           int mi_row, int mi_col,
158                           BLOCK_SIZE bsize) {
159   const int mis = cm->mi_stride;
160   int bw, bh;
161   const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
162 
163   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
164     return;
165 
166   bw = num_8x8_blocks_wide_lookup[mi[0]->mbmi.sb_type];
167   bh = num_8x8_blocks_high_lookup[mi[0]->mbmi.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,
182                no_pred_segcounts, temporal_predictor_count, t_unpred_seg_counts,
183                hbs, bs, mi_row, 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],
195                     no_pred_segcounts, temporal_predictor_count,
196                     t_unpred_seg_counts,
197                     mi_row + mi_dr, mi_col + mi_dc, subsize);
198     }
199   }
200 }
201 
vp9_choose_segmap_coding_method(VP9_COMMON * cm,MACROBLOCKD * xd)202 void vp9_choose_segmap_coding_method(VP9_COMMON *cm, MACROBLOCKD *xd) {
203   struct segmentation *seg = &cm->seg;
204 
205   int no_pred_cost;
206   int t_pred_cost = INT_MAX;
207 
208   int i, tile_col, mi_row, mi_col;
209 
210   int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
211   int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
212   int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
213 
214   vp9_prob no_pred_tree[SEG_TREE_PROBS];
215   vp9_prob t_pred_tree[SEG_TREE_PROBS];
216   vp9_prob t_nopred_prob[PREDICTION_PROBS];
217 
218   // Set default state for the segment tree probabilities and the
219   // temporal coding probabilities
220   vpx_memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
221   vpx_memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
222 
223   // First of all generate stats regarding how well the last segment map
224   // predicts this one
225   for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
226     TileInfo tile;
227     MODE_INFO **mi_ptr;
228     vp9_tile_init(&tile, cm, 0, tile_col);
229 
230     mi_ptr = cm->mi_grid_visible + tile.mi_col_start;
231     for (mi_row = 0; mi_row < cm->mi_rows;
232          mi_row += 8, mi_ptr += 8 * cm->mi_stride) {
233       MODE_INFO **mi = mi_ptr;
234       for (mi_col = tile.mi_col_start; mi_col < tile.mi_col_end;
235            mi_col += 8, mi += 8)
236         count_segs_sb(cm, xd, &tile, mi, no_pred_segcounts,
237                       temporal_predictor_count, t_unpred_seg_counts,
238                       mi_row, mi_col, BLOCK_64X64);
239     }
240   }
241 
242   // Work out probability tree for coding segments without prediction
243   // and the cost.
244   calc_segtree_probs(no_pred_segcounts, no_pred_tree);
245   no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
246 
247   // Key frames cannot use temporal prediction
248   if (!frame_is_intra_only(cm)) {
249     // Work out probability tree for coding those segments not
250     // predicted using the temporal method and the cost.
251     calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
252     t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
253 
254     // Add in the cost of the signaling for each prediction context.
255     for (i = 0; i < PREDICTION_PROBS; i++) {
256       const int count0 = temporal_predictor_count[i][0];
257       const int count1 = temporal_predictor_count[i][1];
258 
259       t_nopred_prob[i] = get_binary_prob(count0, count1);
260 
261       // Add in the predictor signaling cost
262       t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
263                      count1 * vp9_cost_one(t_nopred_prob[i]);
264     }
265   }
266 
267   // Now choose which coding method to use.
268   if (t_pred_cost < no_pred_cost) {
269     seg->temporal_update = 1;
270     vpx_memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
271     vpx_memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
272   } else {
273     seg->temporal_update = 0;
274     vpx_memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
275   }
276 }
277 
vp9_reset_segment_features(struct segmentation * seg)278 void vp9_reset_segment_features(struct segmentation *seg) {
279   // Set up default state for MB feature flags
280   seg->enabled = 0;
281   seg->update_map = 0;
282   seg->update_data = 0;
283   vpx_memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
284   vp9_clearall_segfeatures(seg);
285 }
286