1 /*
2 * Copyright (c) 2010 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 "vp8/common/common.h"
12 #include "encodemv.h"
13 #include "vp8/common/entropymode.h"
14 #include "vp8/common/systemdependent.h"
15 #include "vpx_ports/system_state.h"
16
17 #include <math.h>
18
19 #ifdef VP8_ENTROPY_STATS
20 extern unsigned int active_section;
21 #endif
22
encode_mvcomponent(vp8_writer * const w,const int v,const struct mv_context * mvc)23 static void encode_mvcomponent(vp8_writer *const w, const int v,
24 const struct mv_context *mvc) {
25 const vp8_prob *p = mvc->prob;
26 const int x = v < 0 ? -v : v;
27
28 if (x < mvnum_short) /* Small */
29 {
30 vp8_write(w, 0, p[mvpis_short]);
31 vp8_treed_write(w, vp8_small_mvtree, p + MVPshort, x, 3);
32
33 if (!x) return; /* no sign bit */
34 } else /* Large */
35 {
36 int i = 0;
37
38 vp8_write(w, 1, p[mvpis_short]);
39
40 do
41 vp8_write(w, (x >> i) & 1, p[MVPbits + i]);
42
43 while (++i < 3);
44
45 i = mvlong_width - 1; /* Skip bit 3, which is sometimes implicit */
46
47 do
48 vp8_write(w, (x >> i) & 1, p[MVPbits + i]);
49
50 while (--i > 3);
51
52 if (x & 0xFFF0) vp8_write(w, (x >> 3) & 1, p[MVPbits + 3]);
53 }
54
55 vp8_write(w, v < 0, p[MVPsign]);
56 }
57 #if 0
58 static int max_mv_r = 0;
59 static int max_mv_c = 0;
60 #endif
vp8_encode_motion_vector(vp8_writer * w,const MV * mv,const MV_CONTEXT * mvc)61 void vp8_encode_motion_vector(vp8_writer *w, const MV *mv,
62 const MV_CONTEXT *mvc) {
63 #if 0
64 {
65 if (abs(mv->row >> 1) > max_mv_r)
66 {
67 FILE *f = fopen("maxmv.stt", "a");
68 max_mv_r = abs(mv->row >> 1);
69 fprintf(f, "New Mv Row Max %6d\n", (mv->row >> 1));
70
71 if ((abs(mv->row) / 2) != max_mv_r)
72 fprintf(f, "MV Row conversion error %6d\n", abs(mv->row) / 2);
73
74 fclose(f);
75 }
76
77 if (abs(mv->col >> 1) > max_mv_c)
78 {
79 FILE *f = fopen("maxmv.stt", "a");
80 fprintf(f, "New Mv Col Max %6d\n", (mv->col >> 1));
81 max_mv_c = abs(mv->col >> 1);
82 fclose(f);
83 }
84 }
85 #endif
86
87 encode_mvcomponent(w, mv->row >> 1, &mvc[0]);
88 encode_mvcomponent(w, mv->col >> 1, &mvc[1]);
89 }
90
cost_mvcomponent(const int v,const struct mv_context * mvc)91 static unsigned int cost_mvcomponent(const int v,
92 const struct mv_context *mvc) {
93 const vp8_prob *p = mvc->prob;
94 const int x = v;
95 unsigned int cost;
96
97 if (x < mvnum_short) {
98 cost = vp8_cost_zero(p[mvpis_short]) +
99 vp8_treed_cost(vp8_small_mvtree, p + MVPshort, x, 3);
100
101 if (!x) return cost;
102 } else {
103 int i = 0;
104 cost = vp8_cost_one(p[mvpis_short]);
105
106 do {
107 cost += vp8_cost_bit(p[MVPbits + i], (x >> i) & 1);
108
109 } while (++i < 3);
110
111 i = mvlong_width - 1; /* Skip bit 3, which is sometimes implicit */
112
113 do {
114 cost += vp8_cost_bit(p[MVPbits + i], (x >> i) & 1);
115
116 } while (--i > 3);
117
118 if (x & 0xFFF0) cost += vp8_cost_bit(p[MVPbits + 3], (x >> 3) & 1);
119 }
120
121 return cost; /* + vp8_cost_bit( p [MVPsign], v < 0); */
122 }
123
vp8_build_component_cost_table(int * mvcost[2],const MV_CONTEXT * mvc,int mvc_flag[2])124 void vp8_build_component_cost_table(int *mvcost[2], const MV_CONTEXT *mvc,
125 int mvc_flag[2]) {
126 int i = 1;
127 unsigned int cost0 = 0;
128 unsigned int cost1 = 0;
129
130 vpx_clear_system_state();
131
132 i = 1;
133
134 if (mvc_flag[0]) {
135 mvcost[0][0] = cost_mvcomponent(0, &mvc[0]);
136
137 do {
138 cost0 = cost_mvcomponent(i, &mvc[0]);
139
140 mvcost[0][i] = cost0 + vp8_cost_zero(mvc[0].prob[MVPsign]);
141 mvcost[0][-i] = cost0 + vp8_cost_one(mvc[0].prob[MVPsign]);
142 } while (++i <= mv_max);
143 }
144
145 i = 1;
146
147 if (mvc_flag[1]) {
148 mvcost[1][0] = cost_mvcomponent(0, &mvc[1]);
149
150 do {
151 cost1 = cost_mvcomponent(i, &mvc[1]);
152
153 mvcost[1][i] = cost1 + vp8_cost_zero(mvc[1].prob[MVPsign]);
154 mvcost[1][-i] = cost1 + vp8_cost_one(mvc[1].prob[MVPsign]);
155 } while (++i <= mv_max);
156 }
157 }
158
159 /* Motion vector probability table update depends on benefit.
160 * Small correction allows for the fact that an update to an MV probability
161 * may have benefit in subsequent frames as well as the current one.
162 */
163 #define MV_PROB_UPDATE_CORRECTION -1
164
calc_prob(vp8_prob * p,const unsigned int ct[2])165 static void calc_prob(vp8_prob *p, const unsigned int ct[2]) {
166 const unsigned int tot = ct[0] + ct[1];
167
168 if (tot) {
169 const vp8_prob x = ((ct[0] * 255) / tot) & -2;
170 *p = x ? x : 1;
171 }
172 }
173
update(vp8_writer * const w,const unsigned int ct[2],vp8_prob * const cur_p,const vp8_prob new_p,const vp8_prob update_p,int * updated)174 static void update(vp8_writer *const w, const unsigned int ct[2],
175 vp8_prob *const cur_p, const vp8_prob new_p,
176 const vp8_prob update_p, int *updated) {
177 const int cur_b = vp8_cost_branch(ct, *cur_p);
178 const int new_b = vp8_cost_branch(ct, new_p);
179 const int cost =
180 7 + MV_PROB_UPDATE_CORRECTION +
181 ((vp8_cost_one(update_p) - vp8_cost_zero(update_p) + 128) >> 8);
182
183 if (cur_b - new_b > cost) {
184 *cur_p = new_p;
185 vp8_write(w, 1, update_p);
186 vp8_write_literal(w, new_p >> 1, 7);
187 *updated = 1;
188
189 } else
190 vp8_write(w, 0, update_p);
191 }
192
write_component_probs(vp8_writer * const w,struct mv_context * cur_mvc,const struct mv_context * default_mvc_,const struct mv_context * update_mvc,const unsigned int events[MVvals],unsigned int rc,int * updated)193 static void write_component_probs(vp8_writer *const w,
194 struct mv_context *cur_mvc,
195 const struct mv_context *default_mvc_,
196 const struct mv_context *update_mvc,
197 const unsigned int events[MVvals],
198 unsigned int rc, int *updated) {
199 vp8_prob *Pcur = cur_mvc->prob;
200 const vp8_prob *default_mvc = default_mvc_->prob;
201 const vp8_prob *Pupdate = update_mvc->prob;
202 unsigned int is_short_ct[2], sign_ct[2];
203
204 unsigned int bit_ct[mvlong_width][2];
205
206 unsigned int short_ct[mvnum_short];
207 unsigned int short_bct[mvnum_short - 1][2];
208
209 vp8_prob Pnew[MVPcount];
210
211 (void)rc;
212 vp8_copy_array(Pnew, default_mvc, MVPcount);
213
214 vp8_zero(is_short_ct) vp8_zero(sign_ct) vp8_zero(bit_ct) vp8_zero(short_ct)
215 vp8_zero(short_bct)
216
217 /* j=0 */
218 {
219 const int c = events[mv_max];
220
221 is_short_ct[0] += c; /* Short vector */
222 short_ct[0] += c; /* Magnitude distribution */
223 }
224
225 /* j: 1 ~ mv_max (1023) */
226 {
227 int j = 1;
228
229 do {
230 const int c1 = events[mv_max + j]; /* positive */
231 const int c2 = events[mv_max - j]; /* negative */
232 const int c = c1 + c2;
233 int a = j;
234
235 sign_ct[0] += c1;
236 sign_ct[1] += c2;
237
238 if (a < mvnum_short) {
239 is_short_ct[0] += c; /* Short vector */
240 short_ct[a] += c; /* Magnitude distribution */
241 } else {
242 int k = mvlong_width - 1;
243 is_short_ct[1] += c; /* Long vector */
244
245 /* bit 3 not always encoded. */
246 do {
247 bit_ct[k][(a >> k) & 1] += c;
248
249 } while (--k >= 0);
250 }
251 } while (++j <= mv_max);
252 }
253
254 calc_prob(Pnew + mvpis_short, is_short_ct);
255
256 calc_prob(Pnew + MVPsign, sign_ct);
257
258 {
259 vp8_prob p[mvnum_short - 1]; /* actually only need branch ct */
260 int j = 0;
261
262 vp8_tree_probs_from_distribution(8, vp8_small_mvencodings, vp8_small_mvtree,
263 p, short_bct, short_ct, 256, 1);
264
265 do {
266 calc_prob(Pnew + MVPshort + j, short_bct[j]);
267
268 } while (++j < mvnum_short - 1);
269 }
270
271 {
272 int j = 0;
273
274 do {
275 calc_prob(Pnew + MVPbits + j, bit_ct[j]);
276
277 } while (++j < mvlong_width);
278 }
279
280 update(w, is_short_ct, Pcur + mvpis_short, Pnew[mvpis_short], *Pupdate++,
281 updated);
282
283 update(w, sign_ct, Pcur + MVPsign, Pnew[MVPsign], *Pupdate++, updated);
284
285 {
286 const vp8_prob *const new_p = Pnew + MVPshort;
287 vp8_prob *const cur_p = Pcur + MVPshort;
288
289 int j = 0;
290
291 do {
292 update(w, short_bct[j], cur_p + j, new_p[j], *Pupdate++, updated);
293
294 } while (++j < mvnum_short - 1);
295 }
296
297 {
298 const vp8_prob *const new_p = Pnew + MVPbits;
299 vp8_prob *const cur_p = Pcur + MVPbits;
300
301 int j = 0;
302
303 do {
304 update(w, bit_ct[j], cur_p + j, new_p[j], *Pupdate++, updated);
305
306 } while (++j < mvlong_width);
307 }
308 }
309
vp8_write_mvprobs(VP8_COMP * cpi)310 void vp8_write_mvprobs(VP8_COMP *cpi) {
311 vp8_writer *const w = cpi->bc;
312 MV_CONTEXT *mvc = cpi->common.fc.mvc;
313 int flags[2] = { 0, 0 };
314 #ifdef VP8_ENTROPY_STATS
315 active_section = 4;
316 #endif
317 write_component_probs(w, &mvc[0], &vp8_default_mv_context[0],
318 &vp8_mv_update_probs[0], cpi->mb.MVcount[0], 0,
319 &flags[0]);
320 write_component_probs(w, &mvc[1], &vp8_default_mv_context[1],
321 &vp8_mv_update_probs[1], cpi->mb.MVcount[1], 1,
322 &flags[1]);
323
324 if (flags[0] || flags[1]) {
325 vp8_build_component_cost_table(
326 cpi->mb.mvcost, (const MV_CONTEXT *)cpi->common.fc.mvc, flags);
327 }
328
329 #ifdef VP8_ENTROPY_STATS
330 active_section = 5;
331 #endif
332 }
333