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 12 #include "vp8/common/common.h" 13 #include "encodemv.h" 14 #include "vp8/common/entropymode.h" 15 #include "vp8/common/systemdependent.h" 16 17 #include <math.h> 18 19 #ifdef ENTROPY_STATS 20 extern unsigned int active_section; 21 #endif 22 23 static void encode_mvcomponent( 24 vp8_writer *const w, 25 const int v, 26 const struct mv_context *mvc 27 ) 28 { 29 const vp8_prob *p = mvc->prob; 30 const int x = v < 0 ? -v : v; 31 32 if (x < mvnum_short) /* Small */ 33 { 34 vp8_write(w, 0, p [mvpis_short]); 35 vp8_treed_write(w, vp8_small_mvtree, p + MVPshort, x, 3); 36 37 if (!x) 38 return; /* no sign bit */ 39 } 40 else /* Large */ 41 { 42 int i = 0; 43 44 vp8_write(w, 1, p [mvpis_short]); 45 46 do 47 vp8_write(w, (x >> i) & 1, p [MVPbits + i]); 48 49 while (++i < 3); 50 51 i = mvlong_width - 1; /* Skip bit 3, which is sometimes implicit */ 52 53 do 54 vp8_write(w, (x >> i) & 1, p [MVPbits + i]); 55 56 while (--i > 3); 57 58 if (x & 0xFFF0) 59 vp8_write(w, (x >> 3) & 1, p [MVPbits + 3]); 60 } 61 62 vp8_write(w, v < 0, p [MVPsign]); 63 } 64 #if 0 65 static int max_mv_r = 0; 66 static int max_mv_c = 0; 67 #endif 68 void vp8_encode_motion_vector(vp8_writer *w, const MV *mv, const MV_CONTEXT *mvc) 69 { 70 71 #if 0 72 { 73 if (abs(mv->row >> 1) > max_mv_r) 74 { 75 FILE *f = fopen("maxmv.stt", "a"); 76 max_mv_r = abs(mv->row >> 1); 77 fprintf(f, "New Mv Row Max %6d\n", (mv->row >> 1)); 78 79 if ((abs(mv->row) / 2) != max_mv_r) 80 fprintf(f, "MV Row conversion error %6d\n", abs(mv->row) / 2); 81 82 fclose(f); 83 } 84 85 if (abs(mv->col >> 1) > max_mv_c) 86 { 87 FILE *f = fopen("maxmv.stt", "a"); 88 fprintf(f, "New Mv Col Max %6d\n", (mv->col >> 1)); 89 max_mv_c = abs(mv->col >> 1); 90 fclose(f); 91 } 92 } 93 #endif 94 95 encode_mvcomponent(w, mv->row >> 1, &mvc[0]); 96 encode_mvcomponent(w, mv->col >> 1, &mvc[1]); 97 } 98 99 100 static unsigned int cost_mvcomponent(const int v, const struct mv_context *mvc) 101 { 102 const vp8_prob *p = mvc->prob; 103 const int x = v; 104 unsigned int cost; 105 106 if (x < mvnum_short) 107 { 108 cost = vp8_cost_zero(p [mvpis_short]) 109 + vp8_treed_cost(vp8_small_mvtree, p + MVPshort, x, 3); 110 111 if (!x) 112 return cost; 113 } 114 else 115 { 116 int i = 0; 117 cost = vp8_cost_one(p [mvpis_short]); 118 119 do 120 cost += vp8_cost_bit(p [MVPbits + i], (x >> i) & 1); 121 122 while (++i < 3); 123 124 i = mvlong_width - 1; /* Skip bit 3, which is sometimes implicit */ 125 126 do 127 cost += vp8_cost_bit(p [MVPbits + i], (x >> i) & 1); 128 129 while (--i > 3); 130 131 if (x & 0xFFF0) 132 cost += vp8_cost_bit(p [MVPbits + 3], (x >> 3) & 1); 133 } 134 135 return cost; /* + vp8_cost_bit( p [MVPsign], v < 0); */ 136 } 137 138 void vp8_build_component_cost_table(int *mvcost[2], const MV_CONTEXT *mvc, int mvc_flag[2]) 139 { 140 int i = 1; 141 unsigned int cost0 = 0; 142 unsigned int cost1 = 0; 143 144 vp8_clear_system_state(); 145 146 i = 1; 147 148 if (mvc_flag[0]) 149 { 150 mvcost [0] [0] = cost_mvcomponent(0, &mvc[0]); 151 152 do 153 { 154 cost0 = cost_mvcomponent(i, &mvc[0]); 155 156 mvcost [0] [i] = cost0 + vp8_cost_zero(mvc[0].prob[MVPsign]); 157 mvcost [0] [-i] = cost0 + vp8_cost_one(mvc[0].prob[MVPsign]); 158 } 159 while (++i <= mv_max); 160 } 161 162 i = 1; 163 164 if (mvc_flag[1]) 165 { 166 mvcost [1] [0] = cost_mvcomponent(0, &mvc[1]); 167 168 do 169 { 170 cost1 = cost_mvcomponent(i, &mvc[1]); 171 172 mvcost [1] [i] = cost1 + vp8_cost_zero(mvc[1].prob[MVPsign]); 173 mvcost [1] [-i] = cost1 + vp8_cost_one(mvc[1].prob[MVPsign]); 174 } 175 while (++i <= mv_max); 176 } 177 } 178 179 180 /* Motion vector probability table update depends on benefit. 181 * Small correction allows for the fact that an update to an MV probability 182 * may have benefit in subsequent frames as well as the current one. 183 */ 184 #define MV_PROB_UPDATE_CORRECTION -1 185 186 187 static void calc_prob(vp8_prob *p, const unsigned int ct[2]) 188 { 189 const unsigned int tot = ct[0] + ct[1]; 190 191 if (tot) 192 { 193 const vp8_prob x = ((ct[0] * 255) / tot) & -2; 194 *p = x ? x : 1; 195 } 196 } 197 198 static void update( 199 vp8_writer *const w, 200 const unsigned int ct[2], 201 vp8_prob *const cur_p, 202 const vp8_prob new_p, 203 const vp8_prob update_p, 204 int *updated 205 ) 206 { 207 const int cur_b = vp8_cost_branch(ct, *cur_p); 208 const int new_b = vp8_cost_branch(ct, new_p); 209 const int cost = 7 + MV_PROB_UPDATE_CORRECTION + ((vp8_cost_one(update_p) - vp8_cost_zero(update_p) + 128) >> 8); 210 211 if (cur_b - new_b > cost) 212 { 213 *cur_p = new_p; 214 vp8_write(w, 1, update_p); 215 vp8_write_literal(w, new_p >> 1, 7); 216 *updated = 1; 217 218 } 219 else 220 vp8_write(w, 0, update_p); 221 } 222 223 static void write_component_probs( 224 vp8_writer *const w, 225 struct mv_context *cur_mvc, 226 const struct mv_context *default_mvc_, 227 const struct mv_context *update_mvc, 228 const unsigned int events [MVvals], 229 unsigned int rc, 230 int *updated 231 ) 232 { 233 vp8_prob *Pcur = cur_mvc->prob; 234 const vp8_prob *default_mvc = default_mvc_->prob; 235 const vp8_prob *Pupdate = update_mvc->prob; 236 unsigned int is_short_ct[2], sign_ct[2]; 237 238 unsigned int bit_ct [mvlong_width] [2]; 239 240 unsigned int short_ct [mvnum_short]; 241 unsigned int short_bct [mvnum_short-1] [2]; 242 243 vp8_prob Pnew [MVPcount]; 244 245 (void) rc; 246 vp8_copy_array(Pnew, default_mvc, MVPcount); 247 248 vp8_zero(is_short_ct) 249 vp8_zero(sign_ct) 250 vp8_zero(bit_ct) 251 vp8_zero(short_ct) 252 vp8_zero(short_bct) 253 254 255 /* j=0 */ 256 { 257 const int c = events [mv_max]; 258 259 is_short_ct [0] += c; /* Short vector */ 260 short_ct [0] += c; /* Magnitude distribution */ 261 } 262 263 /* j: 1 ~ mv_max (1023) */ 264 { 265 int j = 1; 266 267 do 268 { 269 const int c1 = events [mv_max + j]; /* positive */ 270 const int c2 = events [mv_max - j]; /* negative */ 271 const int c = c1 + c2; 272 int a = j; 273 274 sign_ct [0] += c1; 275 sign_ct [1] += c2; 276 277 if (a < mvnum_short) 278 { 279 is_short_ct [0] += c; /* Short vector */ 280 short_ct [a] += c; /* Magnitude distribution */ 281 } 282 else 283 { 284 int k = mvlong_width - 1; 285 is_short_ct [1] += c; /* Long vector */ 286 287 /* bit 3 not always encoded. */ 288 do 289 bit_ct [k] [(a >> k) & 1] += c; 290 291 while (--k >= 0); 292 } 293 } 294 while (++j <= mv_max); 295 } 296 297 calc_prob(Pnew + mvpis_short, is_short_ct); 298 299 calc_prob(Pnew + MVPsign, sign_ct); 300 301 { 302 vp8_prob p [mvnum_short - 1]; /* actually only need branch ct */ 303 int j = 0; 304 305 vp8_tree_probs_from_distribution( 306 8, vp8_small_mvencodings, vp8_small_mvtree, 307 p, short_bct, short_ct, 308 256, 1 309 ); 310 311 do 312 calc_prob(Pnew + MVPshort + j, short_bct[j]); 313 314 while (++j < mvnum_short - 1); 315 } 316 317 { 318 int j = 0; 319 320 do 321 calc_prob(Pnew + MVPbits + j, bit_ct[j]); 322 323 while (++j < mvlong_width); 324 } 325 326 update(w, is_short_ct, Pcur + mvpis_short, Pnew[mvpis_short], *Pupdate++, updated); 327 328 update(w, sign_ct, Pcur + MVPsign, Pnew[MVPsign], *Pupdate++, updated); 329 330 { 331 const vp8_prob *const new_p = Pnew + MVPshort; 332 vp8_prob *const cur_p = Pcur + MVPshort; 333 334 int j = 0; 335 336 do 337 338 update(w, short_bct[j], cur_p + j, new_p[j], *Pupdate++, updated); 339 340 while (++j < mvnum_short - 1); 341 } 342 343 { 344 const vp8_prob *const new_p = Pnew + MVPbits; 345 vp8_prob *const cur_p = Pcur + MVPbits; 346 347 int j = 0; 348 349 do 350 351 update(w, bit_ct[j], cur_p + j, new_p[j], *Pupdate++, updated); 352 353 while (++j < mvlong_width); 354 } 355 } 356 357 void vp8_write_mvprobs(VP8_COMP *cpi) 358 { 359 vp8_writer *const w = cpi->bc; 360 MV_CONTEXT *mvc = cpi->common.fc.mvc; 361 int flags[2] = {0, 0}; 362 #ifdef ENTROPY_STATS 363 active_section = 4; 364 #endif 365 write_component_probs( 366 w, &mvc[0], &vp8_default_mv_context[0], &vp8_mv_update_probs[0], 367 cpi->mb.MVcount[0], 0, &flags[0] 368 ); 369 write_component_probs( 370 w, &mvc[1], &vp8_default_mv_context[1], &vp8_mv_update_probs[1], 371 cpi->mb.MVcount[1], 1, &flags[1] 372 ); 373 374 if (flags[0] || flags[1]) 375 vp8_build_component_cost_table(cpi->mb.mvcost, (const MV_CONTEXT *) cpi->common.fc.mvc, flags); 376 377 #ifdef ENTROPY_STATS 378 active_section = 5; 379 #endif 380 } 381
