1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*
* Copyright (c) 2013 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "vp9/common/vp9_common.h"
#include "vp9/common/vp9_entropy.h"
#include "vp9/encoder/vp9_boolhuff.h"
#include "vp9/encoder/vp9_treewriter.h"
#define vp9_cost_upd ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd)) >> 8)
#define vp9_cost_upd256 ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd)))
static int update_bits[255];
static int count_uniform(int v, int n) {
int l = get_unsigned_bits(n);
int m;
if (l == 0) return 0;
m = (1 << l) - n;
if (v < m)
return l - 1;
else
return l;
}
static int split_index(int i, int n, int modulus) {
int max1 = (n - 1 - modulus / 2) / modulus + 1;
if (i % modulus == modulus / 2)
i = i / modulus;
else
i = max1 + i - (i + modulus - modulus / 2) / modulus;
return i;
}
static int recenter_nonneg(int v, int m) {
if (v > (m << 1))
return v;
else if (v >= m)
return ((v - m) << 1);
else
return ((m - v) << 1) - 1;
}
static int remap_prob(int v, int m) {
int i;
static const int map_table[MAX_PROB - 1] = {
// generated by:
// map_table[j] = split_index(j, MAX_PROB - 1, MODULUS_PARAM);
20, 21, 22, 23, 24, 25, 0, 26, 27, 28, 29, 30, 31, 32, 33,
34, 35, 36, 37, 1, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
48, 49, 2, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
3, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 4, 74,
75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 5, 86, 87, 88,
89, 90, 91, 92, 93, 94, 95, 96, 97, 6, 98, 99, 100, 101, 102,
103, 104, 105, 106, 107, 108, 109, 7, 110, 111, 112, 113, 114, 115, 116,
117, 118, 119, 120, 121, 8, 122, 123, 124, 125, 126, 127, 128, 129, 130,
131, 132, 133, 9, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144,
145, 10, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 11,
158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 12, 170, 171,
172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 13, 182, 183, 184, 185,
186, 187, 188, 189, 190, 191, 192, 193, 14, 194, 195, 196, 197, 198, 199,
200, 201, 202, 203, 204, 205, 15, 206, 207, 208, 209, 210, 211, 212, 213,
214, 215, 216, 217, 16, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227,
228, 229, 17, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241,
18, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 19,
};
v--;
m--;
if ((m << 1) <= MAX_PROB)
i = recenter_nonneg(v, m) - 1;
else
i = recenter_nonneg(MAX_PROB - 1 - v, MAX_PROB - 1 - m) - 1;
i = map_table[i];
return i;
}
static int count_term_subexp(int word, int k, int num_syms) {
int count = 0;
int i = 0;
int mk = 0;
while (1) {
int b = (i ? k + i - 1 : k);
int a = (1 << b);
if (num_syms <= mk + 3 * a) {
count += count_uniform(word - mk, num_syms - mk);
break;
} else {
int t = (word >= mk + a);
count++;
if (t) {
i = i + 1;
mk += a;
} else {
count += b;
break;
}
}
}
return count;
}
static int prob_diff_update_cost(vp9_prob newp, vp9_prob oldp) {
int delp = remap_prob(newp, oldp);
return update_bits[delp] * 256;
}
static void encode_uniform(vp9_writer *w, int v, int n) {
int l = get_unsigned_bits(n);
int m;
if (l == 0)
return;
m = (1 << l) - n;
if (v < m) {
vp9_write_literal(w, v, l - 1);
} else {
vp9_write_literal(w, m + ((v - m) >> 1), l - 1);
vp9_write_literal(w, (v - m) & 1, 1);
}
}
static void encode_term_subexp(vp9_writer *w, int word, int k, int num_syms) {
int i = 0;
int mk = 0;
while (1) {
int b = (i ? k + i - 1 : k);
int a = (1 << b);
if (num_syms <= mk + 3 * a) {
encode_uniform(w, word - mk, num_syms - mk);
break;
} else {
int t = (word >= mk + a);
vp9_write_literal(w, t, 1);
if (t) {
i = i + 1;
mk += a;
} else {
vp9_write_literal(w, word - mk, b);
break;
}
}
}
}
void vp9_write_prob_diff_update(vp9_writer *w, vp9_prob newp, vp9_prob oldp) {
const int delp = remap_prob(newp, oldp);
encode_term_subexp(w, delp, SUBEXP_PARAM, 255);
}
void vp9_compute_update_table() {
int i;
for (i = 0; i < 254; i++)
update_bits[i] = count_term_subexp(i, SUBEXP_PARAM, 255);
}
int vp9_prob_diff_update_savings_search(const unsigned int *ct,
vp9_prob oldp, vp9_prob *bestp,
vp9_prob upd) {
const int old_b = cost_branch256(ct, oldp);
int bestsavings = 0;
vp9_prob newp, bestnewp = oldp;
const int step = *bestp > oldp ? -1 : 1;
for (newp = *bestp; newp != oldp; newp += step) {
const int new_b = cost_branch256(ct, newp);
const int update_b = prob_diff_update_cost(newp, oldp) + vp9_cost_upd256;
const int savings = old_b - new_b - update_b;
if (savings > bestsavings) {
bestsavings = savings;
bestnewp = newp;
}
}
*bestp = bestnewp;
return bestsavings;
}
int vp9_prob_diff_update_savings_search_model(const unsigned int *ct,
const vp9_prob *oldp,
vp9_prob *bestp,
vp9_prob upd,
int b, int r) {
int i, old_b, new_b, update_b, savings, bestsavings, step;
int newp;
vp9_prob bestnewp, newplist[ENTROPY_NODES], oldplist[ENTROPY_NODES];
vp9_model_to_full_probs(oldp, oldplist);
vpx_memcpy(newplist, oldp, sizeof(vp9_prob) * UNCONSTRAINED_NODES);
for (i = UNCONSTRAINED_NODES, old_b = 0; i < ENTROPY_NODES; ++i)
old_b += cost_branch256(ct + 2 * i, oldplist[i]);
old_b += cost_branch256(ct + 2 * PIVOT_NODE, oldplist[PIVOT_NODE]);
bestsavings = 0;
bestnewp = oldp[PIVOT_NODE];
step = (*bestp > oldp[PIVOT_NODE] ? -1 : 1);
for (newp = *bestp; newp != oldp[PIVOT_NODE]; newp += step) {
if (newp < 1 || newp > 255)
continue;
newplist[PIVOT_NODE] = newp;
vp9_model_to_full_probs(newplist, newplist);
for (i = UNCONSTRAINED_NODES, new_b = 0; i < ENTROPY_NODES; ++i)
new_b += cost_branch256(ct + 2 * i, newplist[i]);
new_b += cost_branch256(ct + 2 * PIVOT_NODE, newplist[PIVOT_NODE]);
update_b = prob_diff_update_cost(newp, oldp[PIVOT_NODE]) +
vp9_cost_upd256;
savings = old_b - new_b - update_b;
if (savings > bestsavings) {
bestsavings = savings;
bestnewp = newp;
}
}
*bestp = bestnewp;
return bestsavings;
}
void vp9_cond_prob_diff_update(vp9_writer *w, vp9_prob *oldp,
vp9_prob upd, unsigned int *ct) {
vp9_prob newp = get_binary_prob(ct[0], ct[1]);
const int savings = vp9_prob_diff_update_savings_search(ct, *oldp, &newp,
upd);
assert(newp >= 1);
if (savings > 0) {
vp9_write(w, 1, upd);
vp9_write_prob_diff_update(w, newp, *oldp);
*oldp = newp;
} else {
vp9_write(w, 0, upd);
}
}
|
