media/libvpx/vp9/encoder/vp9_segmentation.c@ac0c01689b40
media/libvpx/vp9/encoder/vp9_segmentation.c
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
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 */
12 #include <limits.h>
13 #include "vpx_mem/vpx_mem.h"
14 #include "vp9/encoder/vp9_segmentation.h"
15 #include "vp9/common/vp9_pred_common.h"
16 #include "vp9/common/vp9_tile_common.h"
18 void vp9_enable_segmentation(VP9_PTR ptr) {
19 VP9_COMP *cpi = (VP9_COMP *)ptr;
20 struct segmentation *const seg = &cpi->common.seg;
22 seg->enabled = 1;
23 seg->update_map = 1;
24 seg->update_data = 1;
25 }
27 void vp9_disable_segmentation(VP9_PTR ptr) {
28 VP9_COMP *cpi = (VP9_COMP *)ptr;
29 struct segmentation *const seg = &cpi->common.seg;
30 seg->enabled = 0;
31 }
33 void vp9_set_segmentation_map(VP9_PTR ptr,
34 unsigned char *segmentation_map) {
35 VP9_COMP *cpi = (VP9_COMP *)ptr;
36 struct segmentation *const seg = &cpi->common.seg;
38 // Copy in the new segmentation map
39 vpx_memcpy(cpi->segmentation_map, segmentation_map,
40 (cpi->common.mi_rows * cpi->common.mi_cols));
42 // Signal that the map should be updated.
43 seg->update_map = 1;
44 seg->update_data = 1;
45 }
47 void vp9_set_segment_data(VP9_PTR ptr,
48 signed char *feature_data,
49 unsigned char abs_delta) {
50 VP9_COMP *cpi = (VP9_COMP *)ptr;
51 struct segmentation *const seg = &cpi->common.seg;
53 seg->abs_delta = abs_delta;
55 vpx_memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
57 // TBD ?? Set the feature mask
58 // vpx_memcpy(cpi->mb.e_mbd.segment_feature_mask, 0,
59 // sizeof(cpi->mb.e_mbd.segment_feature_mask));
60 }
62 // Based on set of segment counts calculate a probability tree
63 static void calc_segtree_probs(int *segcounts, vp9_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];
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 }
79 // Based on set of segment counts and probabilities calculate a cost estimate
80 static int cost_segmap(int *segcounts, vp9_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;
88 // Cost the top node of the tree
89 int cost = c0123 * vp9_cost_zero(probs[0]) +
90 c4567 * vp9_cost_one(probs[0]);
92 // Cost subsequent levels
93 if (c0123 > 0) {
94 cost += c01 * vp9_cost_zero(probs[1]) +
95 c23 * vp9_cost_one(probs[1]);
97 if (c01 > 0)
98 cost += segcounts[0] * vp9_cost_zero(probs[3]) +
99 segcounts[1] * vp9_cost_one(probs[3]);
100 if (c23 > 0)
101 cost += segcounts[2] * vp9_cost_zero(probs[4]) +
102 segcounts[3] * vp9_cost_one(probs[4]);
103 }
105 if (c4567 > 0) {
106 cost += c45 * vp9_cost_zero(probs[2]) +
107 c67 * vp9_cost_one(probs[2]);
109 if (c45 > 0)
110 cost += segcounts[4] * vp9_cost_zero(probs[5]) +
111 segcounts[5] * vp9_cost_one(probs[5]);
112 if (c67 > 0)
113 cost += segcounts[6] * vp9_cost_zero(probs[6]) +
114 segcounts[7] * vp9_cost_one(probs[6]);
115 }
117 return cost;
118 }
120 static void count_segs(VP9_COMP *cpi, const TileInfo *const tile,
121 MODE_INFO **mi_8x8,
122 int *no_pred_segcounts,
123 int (*temporal_predictor_count)[2],
124 int *t_unpred_seg_counts,
125 int bw, int bh, int mi_row, int mi_col) {
126 VP9_COMMON *const cm = &cpi->common;
127 MACROBLOCKD *const xd = &cpi->mb.e_mbd;
128 int segment_id;
130 if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
131 return;
133 xd->mi_8x8 = mi_8x8;
134 segment_id = xd->mi_8x8[0]->mbmi.segment_id;
136 set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
138 // Count the number of hits on each segment with no prediction
139 no_pred_segcounts[segment_id]++;
141 // Temporal prediction not allowed on key frames
142 if (cm->frame_type != KEY_FRAME) {
143 const BLOCK_SIZE bsize = mi_8x8[0]->mbmi.sb_type;
144 // Test to see if the segment id matches the predicted value.
145 const int pred_segment_id = vp9_get_segment_id(cm, cm->last_frame_seg_map,
146 bsize, mi_row, mi_col);
147 const int pred_flag = pred_segment_id == segment_id;
148 const int pred_context = vp9_get_pred_context_seg_id(xd);
150 // Store the prediction status for this mb and update counts
151 // as appropriate
152 vp9_set_pred_flag_seg_id(xd, pred_flag);
153 temporal_predictor_count[pred_context][pred_flag]++;
155 if (!pred_flag)
156 // Update the "unpredicted" segment count
157 t_unpred_seg_counts[segment_id]++;
158 }
159 }
161 static void count_segs_sb(VP9_COMP *cpi, const TileInfo *const tile,
162 MODE_INFO **mi_8x8,
163 int *no_pred_segcounts,
164 int (*temporal_predictor_count)[2],
165 int *t_unpred_seg_counts,
166 int mi_row, int mi_col,
167 BLOCK_SIZE bsize) {
168 const VP9_COMMON *const cm = &cpi->common;
169 const int mis = cm->mode_info_stride;
170 int bw, bh;
171 const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
173 if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
174 return;
176 bw = num_8x8_blocks_wide_lookup[mi_8x8[0]->mbmi.sb_type];
177 bh = num_8x8_blocks_high_lookup[mi_8x8[0]->mbmi.sb_type];
179 if (bw == bs && bh == bs) {
180 count_segs(cpi, tile, mi_8x8, no_pred_segcounts, temporal_predictor_count,
181 t_unpred_seg_counts, bs, bs, mi_row, mi_col);
182 } else if (bw == bs && bh < bs) {
183 count_segs(cpi, tile, mi_8x8, no_pred_segcounts, temporal_predictor_count,
184 t_unpred_seg_counts, bs, hbs, mi_row, mi_col);
185 count_segs(cpi, tile, mi_8x8 + hbs * mis, no_pred_segcounts,
186 temporal_predictor_count, t_unpred_seg_counts, bs, hbs,
187 mi_row + hbs, mi_col);
188 } else if (bw < bs && bh == bs) {
189 count_segs(cpi, tile, mi_8x8, no_pred_segcounts, temporal_predictor_count,
190 t_unpred_seg_counts, hbs, bs, mi_row, mi_col);
191 count_segs(cpi, tile, mi_8x8 + hbs,
192 no_pred_segcounts, temporal_predictor_count, t_unpred_seg_counts,
193 hbs, bs, mi_row, mi_col + hbs);
194 } else {
195 const BLOCK_SIZE subsize = subsize_lookup[PARTITION_SPLIT][bsize];
196 int n;
198 assert(bw < bs && bh < bs);
200 for (n = 0; n < 4; n++) {
201 const int mi_dc = hbs * (n & 1);
202 const int mi_dr = hbs * (n >> 1);
204 count_segs_sb(cpi, tile, &mi_8x8[mi_dr * mis + mi_dc],
205 no_pred_segcounts, temporal_predictor_count,
206 t_unpred_seg_counts,
207 mi_row + mi_dr, mi_col + mi_dc, subsize);
208 }
209 }
210 }
212 void vp9_choose_segmap_coding_method(VP9_COMP *cpi) {
213 VP9_COMMON *const cm = &cpi->common;
214 struct segmentation *seg = &cm->seg;
216 int no_pred_cost;
217 int t_pred_cost = INT_MAX;
219 int i, tile_col, mi_row, mi_col;
221 int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
222 int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
223 int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
225 vp9_prob no_pred_tree[SEG_TREE_PROBS];
226 vp9_prob t_pred_tree[SEG_TREE_PROBS];
227 vp9_prob t_nopred_prob[PREDICTION_PROBS];
229 const int mis = cm->mode_info_stride;
230 MODE_INFO **mi_ptr, **mi;
232 // Set default state for the segment tree probabilities and the
233 // temporal coding probabilities
234 vpx_memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
235 vpx_memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
237 // First of all generate stats regarding how well the last segment map
238 // predicts this one
239 for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
240 TileInfo tile;
242 vp9_tile_init(&tile, cm, 0, tile_col);
243 mi_ptr = cm->mi_grid_visible + tile.mi_col_start;
244 for (mi_row = 0; mi_row < cm->mi_rows;
245 mi_row += 8, mi_ptr += 8 * mis) {
246 mi = mi_ptr;
247 for (mi_col = tile.mi_col_start; mi_col < tile.mi_col_end;
248 mi_col += 8, mi += 8)
249 count_segs_sb(cpi, &tile, mi, no_pred_segcounts,
250 temporal_predictor_count, t_unpred_seg_counts,
251 mi_row, mi_col, BLOCK_64X64);
252 }
253 }
255 // Work out probability tree for coding segments without prediction
256 // and the cost.
257 calc_segtree_probs(no_pred_segcounts, no_pred_tree);
258 no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
260 // Key frames cannot use temporal prediction
261 if (!frame_is_intra_only(cm)) {
262 // Work out probability tree for coding those segments not
263 // predicted using the temporal method and the cost.
264 calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
265 t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
267 // Add in the cost of the signaling for each prediction context.
268 for (i = 0; i < PREDICTION_PROBS; i++) {
269 const int count0 = temporal_predictor_count[i][0];
270 const int count1 = temporal_predictor_count[i][1];
272 t_nopred_prob[i] = get_binary_prob(count0, count1);
274 // Add in the predictor signaling cost
275 t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
276 count1 * vp9_cost_one(t_nopred_prob[i]);
277 }
278 }
280 // Now choose which coding method to use.
281 if (t_pred_cost < no_pred_cost) {
282 seg->temporal_update = 1;
283 vpx_memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
284 vpx_memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
285 } else {
286 seg->temporal_update = 0;
287 vpx_memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
288 }
289 }
