1// Copyright 2011 Google Inc. 2// 3// This code is licensed under the same terms as WebM: 4// Software License Agreement: http://www.webmproject.org/license/software/ 5// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ 6// ----------------------------------------------------------------------------- 7// 8// frame coding and analysis 9// 10// Author: Skal (pascal.massimino@gmail.com) 11 12#include <stdlib.h> 13#include <string.h> 14#include <assert.h> 15#include <math.h> 16 17#include "vp8enci.h" 18#include "cost.h" 19 20#if defined(__cplusplus) || defined(c_plusplus) 21extern "C" { 22#endif 23 24#define SEGMENT_VISU 0 25#define DEBUG_SEARCH 0 // useful to track search convergence 26 27// On-the-fly info about the current set of residuals. Handy to avoid 28// passing zillions of params. 29typedef struct { 30 int first; 31 int last; 32 const int16_t* coeffs; 33 34 int coeff_type; 35 ProbaArray* prob; 36 StatsArray* stats; 37 CostArray* cost; 38} VP8Residual; 39 40//----------------------------------------------------------------------------- 41// Tables for level coding 42 43const uint8_t VP8EncBands[16 + 1] = { 44 0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 45 0 // sentinel 46}; 47 48static const uint8_t kCat3[] = { 173, 148, 140 }; 49static const uint8_t kCat4[] = { 176, 155, 140, 135 }; 50static const uint8_t kCat5[] = { 180, 157, 141, 134, 130 }; 51static const uint8_t kCat6[] = 52 { 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129 }; 53 54//----------------------------------------------------------------------------- 55// Reset the statistics about: number of skips, token proba, level cost,... 56 57static void ResetStats(VP8Encoder* const enc, int precalc_cost) { 58 VP8Proba* const proba = &enc->proba_; 59 if (precalc_cost) VP8CalculateLevelCosts(proba); 60 proba->nb_skip_ = 0; 61 proba->nb_i4_ = 0; 62 proba->nb_i16_ = 0; 63} 64 65//----------------------------------------------------------------------------- 66// Skip decision probability 67 68static int CalcSkipProba(uint64_t nb, uint64_t total) { 69 return (int)(total ? (total - nb) * 255 / total : 255); 70} 71 72// Returns the bit-cost for coding the skip probability. 73static int FinalizeSkipProba(VP8Encoder* const enc) { 74 VP8Proba* const proba = &enc->proba_; 75 const int nb_mbs = enc->mb_w_ * enc->mb_h_; 76 const int nb_events = proba->nb_skip_; 77 int size; 78 proba->skip_proba_ = CalcSkipProba(nb_events, nb_mbs); 79 proba->use_skip_proba_ = (proba->skip_proba_ < 250); 80 size = 256; // 'use_skip_proba' bit 81 if (proba->use_skip_proba_) { 82 size += nb_events * VP8BitCost(1, proba->skip_proba_) 83 + (nb_mbs - nb_events) * VP8BitCost(0, proba->skip_proba_); 84 size += 8 * 256; // cost of signaling the skip_proba_ itself. 85 } 86 return size; 87} 88 89//----------------------------------------------------------------------------- 90// Recording of token probabilities. 91 92static void ResetTokenStats(VP8Encoder* const enc) { 93 VP8Proba* const proba = &enc->proba_; 94 memset(proba->stats_, 0, sizeof(proba->stats_)); 95} 96 97// Record proba context used 98static int Record(int bit, uint64_t* const stats) { 99 stats[0] += bit; 100 stats[1] += 1; 101 return bit; 102} 103 104// Simulate block coding, but only record statistics. 105// Note: no need to record the fixed probas. 106static int RecordCoeffs(int ctx, VP8Residual* res) { 107 int n = res->first; 108 uint64_t (*s)[2] = res->stats[VP8EncBands[n]][ctx]; 109 if (!Record(res->last >= 0, s[0])) { 110 return 0; 111 } 112 113 while (1) { 114 const int v = abs(res->coeffs[n++]); 115 if (!Record(v != 0, s[1])) { 116 s = res->stats[VP8EncBands[n]][0]; 117 continue; 118 } 119 if (!Record(v > 1, s[2])) { 120 s = res->stats[VP8EncBands[n]][1]; 121 } else { 122 if (!Record(v > 4, s[3])) { 123 if (Record(v != 2, s[4])) 124 Record(v == 4, s[5]); 125 } else if (!Record(v > 10, s[6])) { 126 Record(v > 6, s[7]); 127 } else if (!Record((v >= 3 + (8 << 2)), s[8])) { 128 Record((v >= 3 + (8 << 1)), s[9]); 129 } else { 130 Record((v >= 3 + (8 << 3)), s[10]); 131 } 132 s = res->stats[VP8EncBands[n]][2]; 133 } 134 if (n == 16 || !Record(n <= res->last, s[0])) { 135 return 1; 136 } 137 } 138} 139 140// Collect statistics and deduce probabilities for next coding pass. 141// Return the total bit-cost for coding the probability updates. 142static int CalcTokenProba(uint64_t nb, uint64_t total) { 143 return (int)(nb ? ((total - nb) * 255 + total / 2) / total : 255); 144} 145 146static int FinalizeTokenProbas(VP8Encoder* const enc) { 147 VP8Proba* const proba = &enc->proba_; 148 int size = 0; 149 int t, b, c, p; 150 for (t = 0; t < NUM_TYPES; ++t) { 151 for (b = 0; b < NUM_BANDS; ++b) { 152 for (c = 0; c < NUM_CTX; ++c) { 153 for (p = 0; p < NUM_PROBAS; ++p) { 154 const uint64_t* const cnt = proba->stats_[t][b][c][p]; 155 const int update_proba = VP8CoeffsUpdateProba[t][b][c][p]; 156 const int old_p = VP8CoeffsProba0[t][b][c][p]; 157 const int new_p = CalcTokenProba(cnt[0], cnt[1]); 158 const uint64_t old_cost = VP8BranchCost(cnt[0], cnt[1], old_p) 159 + VP8BitCost(0, update_proba); 160 const uint64_t new_cost = VP8BranchCost(cnt[0], cnt[1], new_p) 161 + VP8BitCost(1, update_proba) + 8 * 256; 162 const int use_new_p = (old_cost > new_cost); 163 size += VP8BitCost(use_new_p, update_proba); 164 if (use_new_p) { // only use proba that seem meaningful enough. 165 proba->coeffs_[t][b][c][p] = new_p; 166 size += 8 * 256; 167 } else { 168 proba->coeffs_[t][b][c][p] = old_p; 169 } 170 } 171 } 172 } 173 } 174 return size; 175} 176 177//----------------------------------------------------------------------------- 178// helper functions for residuals struct VP8Residual. 179 180static void InitResidual(int first, int coeff_type, 181 VP8Encoder* const enc, VP8Residual* const res) { 182 res->coeff_type = coeff_type; 183 res->prob = enc->proba_.coeffs_[coeff_type]; 184 res->stats = enc->proba_.stats_[coeff_type]; 185 res->cost = enc->proba_.level_cost_[coeff_type]; 186 res->first = first; 187} 188 189static void SetResidualCoeffs(const int16_t* const coeffs, 190 VP8Residual* const res) { 191 int n; 192 res->last = -1; 193 for (n = 15; n >= res->first; --n) { 194 if (coeffs[n]) { 195 res->last = n; 196 break; 197 } 198 } 199 res->coeffs = coeffs; 200} 201 202//----------------------------------------------------------------------------- 203// Mode costs 204 205static int GetResidualCost(int ctx, const VP8Residual* const res) { 206 int n = res->first; 207 const uint8_t* p = res->prob[VP8EncBands[n]][ctx]; 208 const uint16_t *t = res->cost[VP8EncBands[n]][ctx]; 209 int cost; 210 211 cost = VP8BitCost(res->last >= 0, p[0]); 212 if (res->last < 0) { 213 return cost; 214 } 215 while (n <= res->last) { 216 const int v = abs(res->coeffs[n++]); 217 cost += VP8LevelCost(t, v); 218 if (v == 0) { 219 p = res->prob[VP8EncBands[n]][0]; 220 t = res->cost[VP8EncBands[n]][0]; 221 continue; 222 } else if (v == 1) { 223 p = res->prob[VP8EncBands[n]][1]; 224 t = res->cost[VP8EncBands[n]][1]; 225 } else { 226 p = res->prob[VP8EncBands[n]][2]; 227 t = res->cost[VP8EncBands[n]][2]; 228 } 229 if (n < 16) { 230 cost += VP8BitCost(n <= res->last, p[0]); 231 } 232 } 233 return cost; 234} 235 236int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]) { 237 const int x = (it->i4_ & 3), y = (it->i4_ >> 2); 238 VP8Residual res; 239 int R = 0; 240 int ctx; 241 242 InitResidual(0, 3, it->enc_, &res); 243 ctx = it->top_nz_[x] + it->left_nz_[y]; 244 SetResidualCoeffs(levels, &res); 245 R += GetResidualCost(ctx, &res); 246 return R; 247} 248 249int VP8GetCostLuma16(VP8EncIterator* const it, const VP8ModeScore* const rd) { 250 VP8Residual res; 251 int x, y; 252 int R = 0; 253 254 VP8IteratorNzToBytes(it); // re-import the non-zero context 255 256 // DC 257 InitResidual(0, 1, it->enc_, &res); 258 SetResidualCoeffs(rd->y_dc_levels, &res); 259 R += GetResidualCost(it->top_nz_[8] + it->left_nz_[8], &res); 260 261 // AC 262 InitResidual(1, 0, it->enc_, &res); 263 for (y = 0; y < 4; ++y) { 264 for (x = 0; x < 4; ++x) { 265 const int ctx = it->top_nz_[x] + it->left_nz_[y]; 266 SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); 267 R += GetResidualCost(ctx, &res); 268 it->top_nz_[x] = it->left_nz_[y] = (res.last >= 0); 269 } 270 } 271 return R; 272} 273 274int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd) { 275 VP8Residual res; 276 int ch, x, y; 277 int R = 0; 278 279 VP8IteratorNzToBytes(it); // re-import the non-zero context 280 281 InitResidual(0, 2, it->enc_, &res); 282 for (ch = 0; ch <= 2; ch += 2) { 283 for (y = 0; y < 2; ++y) { 284 for (x = 0; x < 2; ++x) { 285 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; 286 SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); 287 R += GetResidualCost(ctx, &res); 288 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = (res.last >= 0); 289 } 290 } 291 } 292 return R; 293} 294 295//----------------------------------------------------------------------------- 296// Coefficient coding 297 298static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) { 299 int n = res->first; 300 const uint8_t* p = res->prob[VP8EncBands[n]][ctx]; 301 if (!VP8PutBit(bw, res->last >= 0, p[0])) { 302 return 0; 303 } 304 305 while (n < 16) { 306 const int c = res->coeffs[n++]; 307 const int sign = c < 0; 308 int v = sign ? -c : c; 309 if (!VP8PutBit(bw, v != 0, p[1])) { 310 p = res->prob[VP8EncBands[n]][0]; 311 continue; 312 } 313 if (!VP8PutBit(bw, v > 1, p[2])) { 314 p = res->prob[VP8EncBands[n]][1]; 315 } else { 316 if (!VP8PutBit(bw, v > 4, p[3])) { 317 if (VP8PutBit(bw, v != 2, p[4])) 318 VP8PutBit(bw, v == 4, p[5]); 319 } else if (!VP8PutBit(bw, v > 10, p[6])) { 320 if (!VP8PutBit(bw, v > 6, p[7])) { 321 VP8PutBit(bw, v == 6, 159); 322 } else { 323 VP8PutBit(bw, v >= 9, 165); 324 VP8PutBit(bw, !(v & 1), 145); 325 } 326 } else { 327 int mask; 328 const uint8_t* tab; 329 if (v < 3 + (8 << 1)) { // kCat3 (3b) 330 VP8PutBit(bw, 0, p[8]); 331 VP8PutBit(bw, 0, p[9]); 332 v -= 3 + (8 << 0); 333 mask = 1 << 2; 334 tab = kCat3; 335 } else if (v < 3 + (8 << 2)) { // kCat4 (4b) 336 VP8PutBit(bw, 0, p[8]); 337 VP8PutBit(bw, 1, p[9]); 338 v -= 3 + (8 << 1); 339 mask = 1 << 3; 340 tab = kCat4; 341 } else if (v < 3 + (8 << 3)) { // kCat5 (5b) 342 VP8PutBit(bw, 1, p[8]); 343 VP8PutBit(bw, 0, p[10]); 344 v -= 3 + (8 << 2); 345 mask = 1 << 4; 346 tab = kCat5; 347 } else { // kCat6 (11b) 348 VP8PutBit(bw, 1, p[8]); 349 VP8PutBit(bw, 1, p[10]); 350 v -= 3 + (8 << 3); 351 mask = 1 << 10; 352 tab = kCat6; 353 } 354 while (mask) { 355 VP8PutBit(bw, !!(v & mask), *tab++); 356 mask >>= 1; 357 } 358 } 359 p = res->prob[VP8EncBands[n]][2]; 360 } 361 VP8PutBitUniform(bw, sign); 362 if (n == 16 || !VP8PutBit(bw, n <= res->last, p[0])) { 363 return 1; // EOB 364 } 365 } 366 return 1; 367} 368 369static void CodeResiduals(VP8BitWriter* const bw, 370 VP8EncIterator* const it, 371 const VP8ModeScore* const rd) { 372 int x, y, ch; 373 VP8Residual res; 374 uint64_t pos1, pos2, pos3; 375 const int i16 = (it->mb_->type_ == 1); 376 const int segment = it->mb_->segment_; 377 378 VP8IteratorNzToBytes(it); 379 380 pos1 = VP8BitWriterPos(bw); 381 if (i16) { 382 InitResidual(0, 1, it->enc_, &res); 383 SetResidualCoeffs(rd->y_dc_levels, &res); 384 it->top_nz_[8] = it->left_nz_[8] = 385 PutCoeffs(bw, it->top_nz_[8] + it->left_nz_[8], &res); 386 InitResidual(1, 0, it->enc_, &res); 387 } else { 388 InitResidual(0, 3, it->enc_, &res); 389 } 390 391 // luma-AC 392 for (y = 0; y < 4; ++y) { 393 for (x = 0; x < 4; ++x) { 394 const int ctx = it->top_nz_[x] + it->left_nz_[y]; 395 SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); 396 it->top_nz_[x] = it->left_nz_[y] = PutCoeffs(bw, ctx, &res); 397 } 398 } 399 pos2 = VP8BitWriterPos(bw); 400 401 // U/V 402 InitResidual(0, 2, it->enc_, &res); 403 for (ch = 0; ch <= 2; ch += 2) { 404 for (y = 0; y < 2; ++y) { 405 for (x = 0; x < 2; ++x) { 406 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; 407 SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); 408 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = 409 PutCoeffs(bw, ctx, &res); 410 } 411 } 412 } 413 pos3 = VP8BitWriterPos(bw); 414 it->luma_bits_ = pos2 - pos1; 415 it->uv_bits_ = pos3 - pos2; 416 it->bit_count_[segment][i16] += it->luma_bits_; 417 it->bit_count_[segment][2] += it->uv_bits_; 418 VP8IteratorBytesToNz(it); 419} 420 421// Same as CodeResiduals, but doesn't actually write anything. 422// Instead, it just records the event distribution. 423static void RecordResiduals(VP8EncIterator* const it, 424 const VP8ModeScore* const rd) { 425 int x, y, ch; 426 VP8Residual res; 427 428 VP8IteratorNzToBytes(it); 429 430 if (it->mb_->type_ == 1) { // i16x16 431 InitResidual(0, 1, it->enc_, &res); 432 SetResidualCoeffs(rd->y_dc_levels, &res); 433 it->top_nz_[8] = it->left_nz_[8] = 434 RecordCoeffs(it->top_nz_[8] + it->left_nz_[8], &res); 435 InitResidual(1, 0, it->enc_, &res); 436 } else { 437 InitResidual(0, 3, it->enc_, &res); 438 } 439 440 // luma-AC 441 for (y = 0; y < 4; ++y) { 442 for (x = 0; x < 4; ++x) { 443 const int ctx = it->top_nz_[x] + it->left_nz_[y]; 444 SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); 445 it->top_nz_[x] = it->left_nz_[y] = RecordCoeffs(ctx, &res); 446 } 447 } 448 449 // U/V 450 InitResidual(0, 2, it->enc_, &res); 451 for (ch = 0; ch <= 2; ch += 2) { 452 for (y = 0; y < 2; ++y) { 453 for (x = 0; x < 2; ++x) { 454 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; 455 SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); 456 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = 457 RecordCoeffs(ctx, &res); 458 } 459 } 460 } 461 462 VP8IteratorBytesToNz(it); 463} 464 465//----------------------------------------------------------------------------- 466// ExtraInfo map / Debug function 467 468#if SEGMENT_VISU 469static void SetBlock(uint8_t* p, int value, int size) { 470 int y; 471 for (y = 0; y < size; ++y) { 472 memset(p, value, size); 473 p += BPS; 474 } 475} 476#endif 477 478static void ResetSSE(VP8Encoder* const enc) { 479 memset(enc->sse_, 0, sizeof(enc->sse_)); 480 enc->sse_count_ = 0; 481} 482 483static void StoreSSE(const VP8EncIterator* const it) { 484 VP8Encoder* const enc = it->enc_; 485 const uint8_t* const in = it->yuv_in_; 486 const uint8_t* const out = it->yuv_out_; 487 // Note: not totally accurate at boundary. And doesn't include in-loop filter. 488 enc->sse_[0] += VP8SSE16x16(in + Y_OFF, out + Y_OFF); 489 enc->sse_[1] += VP8SSE8x8(in + U_OFF, out + U_OFF); 490 enc->sse_[2] += VP8SSE8x8(in + V_OFF, out + V_OFF); 491 enc->sse_count_ += 16 * 16; 492} 493 494static void StoreSideInfo(const VP8EncIterator* const it) { 495 VP8Encoder* const enc = it->enc_; 496 const VP8MBInfo* const mb = it->mb_; 497 WebPPicture* const pic = enc->pic_; 498 499 if (pic->stats) { 500 StoreSSE(it); 501 enc->block_count_[0] += (mb->type_ == 0); 502 enc->block_count_[1] += (mb->type_ == 1); 503 enc->block_count_[2] += (mb->skip_ != 0); 504 } 505 506 if (pic->extra_info) { 507 uint8_t* const info = &pic->extra_info[it->x_ + it->y_ * enc->mb_w_]; 508 switch(pic->extra_info_type) { 509 case 1: *info = mb->type_; break; 510 case 2: *info = mb->segment_; break; 511 case 3: *info = enc->dqm_[mb->segment_].quant_; break; 512 case 4: *info = (mb->type_ == 1) ? it->preds_[0] : 0xff; break; 513 case 5: *info = mb->uv_mode_; break; 514 case 6: { 515 const int b = (int)((it->luma_bits_ + it->uv_bits_ + 7) >> 3); 516 *info = (b > 255) ? 255 : b; break; 517 } 518 default: *info = 0; break; 519 }; 520 } 521#if SEGMENT_VISU // visualize segments and prediction modes 522 SetBlock(it->yuv_out_ + Y_OFF, mb->segment_ * 64, 16); 523 SetBlock(it->yuv_out_ + U_OFF, it->preds_[0] * 64, 8); 524 SetBlock(it->yuv_out_ + V_OFF, mb->uv_mode_ * 64, 8); 525#endif 526} 527 528//----------------------------------------------------------------------------- 529// Main loops 530// 531// VP8EncLoop(): does the final bitstream coding. 532 533static void ResetAfterSkip(VP8EncIterator* const it) { 534 if (it->mb_->type_ == 1) { 535 *it->nz_ = 0; // reset all predictors 536 it->left_nz_[8] = 0; 537 } else { 538 *it->nz_ &= (1 << 24); // preserve the dc_nz bit 539 } 540} 541 542int VP8EncLoop(VP8Encoder* const enc) { 543 int i, s, p; 544 VP8EncIterator it; 545 VP8ModeScore info; 546 const int dont_use_skip = !enc->proba_.use_skip_proba_; 547 const int rd_opt = enc->rd_opt_level_; 548 const int kAverageBytesPerMB = 5; // TODO: have a kTable[quality/10] 549 const int bytes_per_parts = 550 enc->mb_w_ * enc->mb_h_ * kAverageBytesPerMB / enc->num_parts_; 551 552 // Initialize the bit-writers 553 for (p = 0; p < enc->num_parts_; ++p) { 554 VP8BitWriterInit(enc->parts_ + p, bytes_per_parts); 555 } 556 557 ResetStats(enc, rd_opt != 0); 558 ResetSSE(enc); 559 560 VP8IteratorInit(enc, &it); 561 VP8InitFilter(&it); 562 do { 563 VP8IteratorImport(&it); 564 // Warning! order is important: first call VP8Decimate() and 565 // *then* decide how to code the skip decision if there's one. 566 if (!VP8Decimate(&it, &info, rd_opt) || dont_use_skip) { 567 CodeResiduals(it.bw_, &it, &info); 568 } else { // reset predictors after a skip 569 ResetAfterSkip(&it); 570 } 571 StoreSideInfo(&it); 572 VP8StoreFilterStats(&it); 573 VP8IteratorExport(&it); 574 } while (VP8IteratorNext(&it, it.yuv_out_)); 575 VP8AdjustFilterStrength(&it); 576 577 // Finalize the partitions 578 for (p = 0; p < enc->num_parts_; ++p) { 579 VP8BitWriterFinish(enc->parts_ + p); 580 } 581 // and byte counters 582 if (enc->pic_->stats) { 583 for (i = 0; i <= 2; ++i) { 584 for (s = 0; s < NUM_MB_SEGMENTS; ++s) { 585 enc->residual_bytes_[i][s] = (int)((it.bit_count_[s][i] + 7) >> 3); 586 } 587 } 588 } 589 return 1; 590} 591 592//----------------------------------------------------------------------------- 593// VP8StatLoop(): only collect statistics (number of skips, token usage, ...) 594// This is used for deciding optimal probabilities. It also 595// modifies the quantizer value if some target (size, PNSR) 596// was specified. 597 598#define kHeaderSizeEstimate (15 + 20 + 10) // TODO: fix better 599 600static int OneStatPass(VP8Encoder* const enc, float q, int rd_opt, int nb_mbs, 601 float* const PSNR) { 602 VP8EncIterator it; 603 uint64_t size = 0; 604 uint64_t distortion = 0; 605 const uint64_t pixel_count = nb_mbs * 384; 606 607 // Make sure the quality parameter is inside valid bounds 608 if (q < 0.) { 609 q = 0; 610 } else if (q > 100.) { 611 q = 100; 612 } 613 614 VP8SetSegmentParams(enc, q); // setup segment quantizations and filters 615 616 ResetStats(enc, rd_opt != 0); 617 ResetTokenStats(enc); 618 619 VP8IteratorInit(enc, &it); 620 do { 621 VP8ModeScore info; 622 VP8IteratorImport(&it); 623 if (VP8Decimate(&it, &info, rd_opt)) { 624 // Just record the number of skips and act like skip_proba is not used. 625 enc->proba_.nb_skip_++; 626 } 627 RecordResiduals(&it, &info); 628 size += info.R; 629 distortion += info.D; 630 } while (VP8IteratorNext(&it, it.yuv_out_) && --nb_mbs > 0); 631 size += FinalizeSkipProba(enc); 632 size += FinalizeTokenProbas(enc); 633 size += enc->segment_hdr_.size_; 634 size = ((size + 1024) >> 11) + kHeaderSizeEstimate; 635 636 if (PSNR) { 637 *PSNR = (float)(10.* log10(255. * 255. * pixel_count / distortion)); 638 } 639 return (int)size; 640} 641 642// successive refinement increments. 643static const int dqs[] = { 20, 15, 10, 8, 6, 4, 2, 1, 0 }; 644 645int VP8StatLoop(VP8Encoder* const enc) { 646 const int do_search = 647 (enc->config_->target_size > 0 || enc->config_->target_PSNR > 0); 648 const int fast_probe = (enc->method_ < 2 && !do_search); 649 float q = enc->config_->quality; 650 int pass; 651 int nb_mbs; 652 653 // Fast mode: quick analysis pass over few mbs. Better than nothing. 654 nb_mbs = enc->mb_w_ * enc->mb_h_; 655 if (fast_probe && nb_mbs > 100) nb_mbs = 100; 656 657 // No target size: just do several pass without changing 'q' 658 if (!do_search) { 659 for (pass = 0; pass < enc->config_->pass; ++pass) { 660 const int rd_opt = (enc->method_ > 2); 661 OneStatPass(enc, q, rd_opt, nb_mbs, NULL); 662 } 663 return 1; 664 } 665 666 // binary search for a size close to target 667 for (pass = 0; pass < enc->config_->pass || (dqs[pass] > 0); ++pass) { 668 const int rd_opt = 1; 669 float PSNR; 670 int criterion; 671 const int size = OneStatPass(enc, q, rd_opt, nb_mbs, &PSNR); 672#if DEBUG_SEARCH 673 printf("#%d size=%d PSNR=%.2f q=%.2f\n", pass, size, PSNR, q); 674#endif 675 676 if (enc->config_->target_PSNR > 0) { 677 criterion = (PSNR < enc->config_->target_PSNR); 678 } else { 679 criterion = (size < enc->config_->target_size); 680 } 681 // dichotomize 682 if (criterion) { 683 q += dqs[pass]; 684 } else { 685 q -= dqs[pass]; 686 } 687 } 688 return 1; 689} 690 691//----------------------------------------------------------------------------- 692 693#if defined(__cplusplus) || defined(c_plusplus) 694} // extern "C" 695#endif 696