1// Copyright 2011 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// frame coding and analysis
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include <string.h>
15#include <math.h>
16
17#include "./cost_enc.h"
18#include "./vp8i_enc.h"
19#include "../dsp/dsp.h"
20#include "../webp/format_constants.h" // RIFF constants
21
22#define SEGMENT_VISU 0
23#define DEBUG_SEARCH 0 // useful to track search convergence
24
25//------------------------------------------------------------------------------
26// multi-pass convergence
27
28#define HEADER_SIZE_ESTIMATE (RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE + \
29 VP8_FRAME_HEADER_SIZE)
30#define DQ_LIMIT 0.4 // convergence is considered reached if dq < DQ_LIMIT
31// we allow 2k of extra head-room in PARTITION0 limit.
32#define PARTITION0_SIZE_LIMIT ((VP8_MAX_PARTITION0_SIZE - 2048ULL) << 11)
33
34typedef struct { // struct for organizing convergence in either size or PSNR
35 int is_first;
36 float dq;
37 float q, last_q;
38 double value, last_value; // PSNR or size
39 double target;
40 int do_size_search;
41} PassStats;
42
43static int InitPassStats(const VP8Encoder* const enc, PassStats* const s) {
44 const uint64_t target_size = (uint64_t)enc->config_->target_size;
45 const int do_size_search = (target_size != 0);
46 const float target_PSNR = enc->config_->target_PSNR;
47
48 s->is_first = 1;
49 s->dq = 10.f;
50 s->q = s->last_q = enc->config_->quality;
51 s->target = do_size_search ? (double)target_size
52 : (target_PSNR > 0.) ? target_PSNR
53 : 40.; // default, just in case
54 s->value = s->last_value = 0.;
55 s->do_size_search = do_size_search;
56 return do_size_search;
57}
58
59static float Clamp(float v, float min, float max) {
60 return (v < min) ? min : (v > max) ? max : v;
61}
62
63static float ComputeNextQ(PassStats* const s) {
64 float dq;
65 if (s->is_first) {
66 dq = (s->value > s->target) ? -s->dq : s->dq;
67 s->is_first = 0;
68 } else if (s->value != s->last_value) {
69 const double slope = (s->target - s->value) / (s->last_value - s->value);
70 dq = (float)(slope * (s->last_q - s->q));
71 } else {
72 dq = 0.; // we're done?!
73 }
74 // Limit variable to avoid large swings.
75 s->dq = Clamp(dq, -30.f, 30.f);
76 s->last_q = s->q;
77 s->last_value = s->value;
78 s->q = Clamp(s->q + s->dq, 0.f, 100.f);
79 return s->q;
80}
81
82//------------------------------------------------------------------------------
83// Tables for level coding
84
85const uint8_t VP8Cat3[] = { 173, 148, 140 };
86const uint8_t VP8Cat4[] = { 176, 155, 140, 135 };
87const uint8_t VP8Cat5[] = { 180, 157, 141, 134, 130 };
88const uint8_t VP8Cat6[] =
89 { 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129 };
90
91//------------------------------------------------------------------------------
92// Reset the statistics about: number of skips, token proba, level cost,...
93
94static void ResetStats(VP8Encoder* const enc) {
95 VP8EncProba* const proba = &enc->proba_;
96 VP8CalculateLevelCosts(proba);
97 proba->nb_skip_ = 0;
98}
99
100//------------------------------------------------------------------------------
101// Skip decision probability
102
103#define SKIP_PROBA_THRESHOLD 250 // value below which using skip_proba is OK.
104
105static int CalcSkipProba(uint64_t nb, uint64_t total) {
106 return (int)(total ? (total - nb) * 255 / total : 255);
107}
108
109// Returns the bit-cost for coding the skip probability.
110static int FinalizeSkipProba(VP8Encoder* const enc) {
111 VP8EncProba* const proba = &enc->proba_;
112 const int nb_mbs = enc->mb_w_ * enc->mb_h_;
113 const int nb_events = proba->nb_skip_;
114 int size;
115 proba->skip_proba_ = CalcSkipProba(nb_events, nb_mbs);
116 proba->use_skip_proba_ = (proba->skip_proba_ < SKIP_PROBA_THRESHOLD);
117 size = 256; // 'use_skip_proba' bit
118 if (proba->use_skip_proba_) {
119 size += nb_events * VP8BitCost(1, proba->skip_proba_)
120 + (nb_mbs - nb_events) * VP8BitCost(0, proba->skip_proba_);
121 size += 8 * 256; // cost of signaling the skip_proba_ itself.
122 }
123 return size;
124}
125
126// Collect statistics and deduce probabilities for next coding pass.
127// Return the total bit-cost for coding the probability updates.
128static int CalcTokenProba(int nb, int total) {
129 assert(nb <= total);
130 return nb ? (255 - nb * 255 / total) : 255;
131}
132
133// Cost of coding 'nb' 1's and 'total-nb' 0's using 'proba' probability.
134static int BranchCost(int nb, int total, int proba) {
135 return nb * VP8BitCost(1, proba) + (total - nb) * VP8BitCost(0, proba);
136}
137
138static void ResetTokenStats(VP8Encoder* const enc) {
139 VP8EncProba* const proba = &enc->proba_;
140 memset(proba->stats_, 0, sizeof(proba->stats_));
141}
142
143static int FinalizeTokenProbas(VP8EncProba* const proba) {
144 int has_changed = 0;
145 int size = 0;
146 int t, b, c, p;
147 for (t = 0; t < NUM_TYPES; ++t) {
148 for (b = 0; b < NUM_BANDS; ++b) {
149 for (c = 0; c < NUM_CTX; ++c) {
150 for (p = 0; p < NUM_PROBAS; ++p) {
151 const proba_t stats = proba->stats_[t][b][c][p];
152 const int nb = (stats >> 0) & 0xffff;
153 const int total = (stats >> 16) & 0xffff;
154 const int update_proba = VP8CoeffsUpdateProba[t][b][c][p];
155 const int old_p = VP8CoeffsProba0[t][b][c][p];
156 const int new_p = CalcTokenProba(nb, total);
157 const int old_cost = BranchCost(nb, total, old_p)
158 + VP8BitCost(0, update_proba);
159 const int new_cost = BranchCost(nb, total, new_p)
160 + VP8BitCost(1, update_proba)
161 + 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 has_changed |= (new_p != old_p);
167 size += 8 * 256;
168 } else {
169 proba->coeffs_[t][b][c][p] = old_p;
170 }
171 }
172 }
173 }
174 }
175 proba->dirty_ = has_changed;
176 return size;
177}
178
179//------------------------------------------------------------------------------
180// Finalize Segment probability based on the coding tree
181
182static int GetProba(int a, int b) {
183 const int total = a + b;
184 return (total == 0) ? 255 // that's the default probability.
185 : (255 * a + total / 2) / total; // rounded proba
186}
187
188static void ResetSegments(VP8Encoder* const enc) {
189 int n;
190 for (n = 0; n < enc->mb_w_ * enc->mb_h_; ++n) {
191 enc->mb_info_[n].segment_ = 0;
192 }
193}
194
195static void SetSegmentProbas(VP8Encoder* const enc) {
196 int p[NUM_MB_SEGMENTS] = { 0 };
197 int n;
198
199 for (n = 0; n < enc->mb_w_ * enc->mb_h_; ++n) {
200 const VP8MBInfo* const mb = &enc->mb_info_[n];
201 p[mb->segment_]++;
202 }
203 if (enc->pic_->stats != NULL) {
204 for (n = 0; n < NUM_MB_SEGMENTS; ++n) {
205 enc->pic_->stats->segment_size[n] = p[n];
206 }
207 }
208 if (enc->segment_hdr_.num_segments_ > 1) {
209 uint8_t* const probas = enc->proba_.segments_;
210 probas[0] = GetProba(p[0] + p[1], p[2] + p[3]);
211 probas[1] = GetProba(p[0], p[1]);
212 probas[2] = GetProba(p[2], p[3]);
213
214 enc->segment_hdr_.update_map_ =
215 (probas[0] != 255) || (probas[1] != 255) || (probas[2] != 255);
216 if (!enc->segment_hdr_.update_map_) ResetSegments(enc);
217 enc->segment_hdr_.size_ =
218 p[0] * (VP8BitCost(0, probas[0]) + VP8BitCost(0, probas[1])) +
219 p[1] * (VP8BitCost(0, probas[0]) + VP8BitCost(1, probas[1])) +
220 p[2] * (VP8BitCost(1, probas[0]) + VP8BitCost(0, probas[2])) +
221 p[3] * (VP8BitCost(1, probas[0]) + VP8BitCost(1, probas[2]));
222 } else {
223 enc->segment_hdr_.update_map_ = 0;
224 enc->segment_hdr_.size_ = 0;
225 }
226}
227
228//------------------------------------------------------------------------------
229// Coefficient coding
230
231static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) {
232 int n = res->first;
233 // should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1
234 const uint8_t* p = res->prob[n][ctx];
235 if (!VP8PutBit(bw, res->last >= 0, p[0])) {
236 return 0;
237 }
238
239 while (n < 16) {
240 const int c = res->coeffs[n++];
241 const int sign = c < 0;
242 int v = sign ? -c : c;
243 if (!VP8PutBit(bw, v != 0, p[1])) {
244 p = res->prob[VP8EncBands[n]][0];
245 continue;
246 }
247 if (!VP8PutBit(bw, v > 1, p[2])) {
248 p = res->prob[VP8EncBands[n]][1];
249 } else {
250 if (!VP8PutBit(bw, v > 4, p[3])) {
251 if (VP8PutBit(bw, v != 2, p[4])) {
252 VP8PutBit(bw, v == 4, p[5]);
253 }
254 } else if (!VP8PutBit(bw, v > 10, p[6])) {
255 if (!VP8PutBit(bw, v > 6, p[7])) {
256 VP8PutBit(bw, v == 6, 159);
257 } else {
258 VP8PutBit(bw, v >= 9, 165);
259 VP8PutBit(bw, !(v & 1), 145);
260 }
261 } else {
262 int mask;
263 const uint8_t* tab;
264 if (v < 3 + (8 << 1)) { // VP8Cat3 (3b)
265 VP8PutBit(bw, 0, p[8]);
266 VP8PutBit(bw, 0, p[9]);
267 v -= 3 + (8 << 0);
268 mask = 1 << 2;
269 tab = VP8Cat3;
270 } else if (v < 3 + (8 << 2)) { // VP8Cat4 (4b)
271 VP8PutBit(bw, 0, p[8]);
272 VP8PutBit(bw, 1, p[9]);
273 v -= 3 + (8 << 1);
274 mask = 1 << 3;
275 tab = VP8Cat4;
276 } else if (v < 3 + (8 << 3)) { // VP8Cat5 (5b)
277 VP8PutBit(bw, 1, p[8]);
278 VP8PutBit(bw, 0, p[10]);
279 v -= 3 + (8 << 2);
280 mask = 1 << 4;
281 tab = VP8Cat5;
282 } else { // VP8Cat6 (11b)
283 VP8PutBit(bw, 1, p[8]);
284 VP8PutBit(bw, 1, p[10]);
285 v -= 3 + (8 << 3);
286 mask = 1 << 10;
287 tab = VP8Cat6;
288 }
289 while (mask) {
290 VP8PutBit(bw, !!(v & mask), *tab++);
291 mask >>= 1;
292 }
293 }
294 p = res->prob[VP8EncBands[n]][2];
295 }
296 VP8PutBitUniform(bw, sign);
297 if (n == 16 || !VP8PutBit(bw, n <= res->last, p[0])) {
298 return 1; // EOB
299 }
300 }
301 return 1;
302}
303
304static void CodeResiduals(VP8BitWriter* const bw, VP8EncIterator* const it,
305 const VP8ModeScore* const rd) {
306 int x, y, ch;
307 VP8Residual res;
308 uint64_t pos1, pos2, pos3;
309 const int i16 = (it->mb_->type_ == 1);
310 const int segment = it->mb_->segment_;
311 VP8Encoder* const enc = it->enc_;
312
313 VP8IteratorNzToBytes(it);
314
315 pos1 = VP8BitWriterPos(bw);
316 if (i16) {
317 VP8InitResidual(0, 1, enc, &res);
318 VP8SetResidualCoeffs(rd->y_dc_levels, &res);
319 it->top_nz_[8] = it->left_nz_[8] =
320 PutCoeffs(bw, it->top_nz_[8] + it->left_nz_[8], &res);
321 VP8InitResidual(1, 0, enc, &res);
322 } else {
323 VP8InitResidual(0, 3, enc, &res);
324 }
325
326 // luma-AC
327 for (y = 0; y < 4; ++y) {
328 for (x = 0; x < 4; ++x) {
329 const int ctx = it->top_nz_[x] + it->left_nz_[y];
330 VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res);
331 it->top_nz_[x] = it->left_nz_[y] = PutCoeffs(bw, ctx, &res);
332 }
333 }
334 pos2 = VP8BitWriterPos(bw);
335
336 // U/V
337 VP8InitResidual(0, 2, enc, &res);
338 for (ch = 0; ch <= 2; ch += 2) {
339 for (y = 0; y < 2; ++y) {
340 for (x = 0; x < 2; ++x) {
341 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
342 VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res);
343 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] =
344 PutCoeffs(bw, ctx, &res);
345 }
346 }
347 }
348 pos3 = VP8BitWriterPos(bw);
349 it->luma_bits_ = pos2 - pos1;
350 it->uv_bits_ = pos3 - pos2;
351 it->bit_count_[segment][i16] += it->luma_bits_;
352 it->bit_count_[segment][2] += it->uv_bits_;
353 VP8IteratorBytesToNz(it);
354}
355
356// Same as CodeResiduals, but doesn't actually write anything.
357// Instead, it just records the event distribution.
358static void RecordResiduals(VP8EncIterator* const it,
359 const VP8ModeScore* const rd) {
360 int x, y, ch;
361 VP8Residual res;
362 VP8Encoder* const enc = it->enc_;
363
364 VP8IteratorNzToBytes(it);
365
366 if (it->mb_->type_ == 1) { // i16x16
367 VP8InitResidual(0, 1, enc, &res);
368 VP8SetResidualCoeffs(rd->y_dc_levels, &res);
369 it->top_nz_[8] = it->left_nz_[8] =
370 VP8RecordCoeffs(it->top_nz_[8] + it->left_nz_[8], &res);
371 VP8InitResidual(1, 0, enc, &res);
372 } else {
373 VP8InitResidual(0, 3, enc, &res);
374 }
375
376 // luma-AC
377 for (y = 0; y < 4; ++y) {
378 for (x = 0; x < 4; ++x) {
379 const int ctx = it->top_nz_[x] + it->left_nz_[y];
380 VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res);
381 it->top_nz_[x] = it->left_nz_[y] = VP8RecordCoeffs(ctx, &res);
382 }
383 }
384
385 // U/V
386 VP8InitResidual(0, 2, enc, &res);
387 for (ch = 0; ch <= 2; ch += 2) {
388 for (y = 0; y < 2; ++y) {
389 for (x = 0; x < 2; ++x) {
390 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
391 VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res);
392 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] =
393 VP8RecordCoeffs(ctx, &res);
394 }
395 }
396 }
397
398 VP8IteratorBytesToNz(it);
399}
400
401//------------------------------------------------------------------------------
402// Token buffer
403
404#if !defined(DISABLE_TOKEN_BUFFER)
405
406static int RecordTokens(VP8EncIterator* const it, const VP8ModeScore* const rd,
407 VP8TBuffer* const tokens) {
408 int x, y, ch;
409 VP8Residual res;
410 VP8Encoder* const enc = it->enc_;
411
412 VP8IteratorNzToBytes(it);
413 if (it->mb_->type_ == 1) { // i16x16
414 const int ctx = it->top_nz_[8] + it->left_nz_[8];
415 VP8InitResidual(0, 1, enc, &res);
416 VP8SetResidualCoeffs(rd->y_dc_levels, &res);
417 it->top_nz_[8] = it->left_nz_[8] =
418 VP8RecordCoeffTokens(ctx, &res, tokens);
419 VP8InitResidual(1, 0, enc, &res);
420 } else {
421 VP8InitResidual(0, 3, enc, &res);
422 }
423
424 // luma-AC
425 for (y = 0; y < 4; ++y) {
426 for (x = 0; x < 4; ++x) {
427 const int ctx = it->top_nz_[x] + it->left_nz_[y];
428 VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res);
429 it->top_nz_[x] = it->left_nz_[y] =
430 VP8RecordCoeffTokens(ctx, &res, tokens);
431 }
432 }
433
434 // U/V
435 VP8InitResidual(0, 2, enc, &res);
436 for (ch = 0; ch <= 2; ch += 2) {
437 for (y = 0; y < 2; ++y) {
438 for (x = 0; x < 2; ++x) {
439 const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
440 VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res);
441 it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] =
442 VP8RecordCoeffTokens(ctx, &res, tokens);
443 }
444 }
445 }
446 VP8IteratorBytesToNz(it);
447 return !tokens->error_;
448}
449
450#endif // !DISABLE_TOKEN_BUFFER
451
452//------------------------------------------------------------------------------
453// ExtraInfo map / Debug function
454
455#if SEGMENT_VISU
456static void SetBlock(uint8_t* p, int value, int size) {
457 int y;
458 for (y = 0; y < size; ++y) {
459 memset(p, value, size);
460 p += BPS;
461 }
462}
463#endif
464
465static void ResetSSE(VP8Encoder* const enc) {
466 enc->sse_[0] = 0;
467 enc->sse_[1] = 0;
468 enc->sse_[2] = 0;
469 // Note: enc->sse_[3] is managed by alpha.c
470 enc->sse_count_ = 0;
471}
472
473static void StoreSSE(const VP8EncIterator* const it) {
474 VP8Encoder* const enc = it->enc_;
475 const uint8_t* const in = it->yuv_in_;
476 const uint8_t* const out = it->yuv_out_;
477 // Note: not totally accurate at boundary. And doesn't include in-loop filter.
478 enc->sse_[0] += VP8SSE16x16(in + Y_OFF_ENC, out + Y_OFF_ENC);
479 enc->sse_[1] += VP8SSE8x8(in + U_OFF_ENC, out + U_OFF_ENC);
480 enc->sse_[2] += VP8SSE8x8(in + V_OFF_ENC, out + V_OFF_ENC);
481 enc->sse_count_ += 16 * 16;
482}
483
484static void StoreSideInfo(const VP8EncIterator* const it) {
485 VP8Encoder* const enc = it->enc_;
486 const VP8MBInfo* const mb = it->mb_;
487 WebPPicture* const pic = enc->pic_;
488
489 if (pic->stats != NULL) {
490 StoreSSE(it);
491 enc->block_count_[0] += (mb->type_ == 0);
492 enc->block_count_[1] += (mb->type_ == 1);
493 enc->block_count_[2] += (mb->skip_ != 0);
494 }
495
496 if (pic->extra_info != NULL) {
497 uint8_t* const info = &pic->extra_info[it->x_ + it->y_ * enc->mb_w_];
498 switch (pic->extra_info_type) {
499 case 1: *info = mb->type_; break;
500 case 2: *info = mb->segment_; break;
501 case 3: *info = enc->dqm_[mb->segment_].quant_; break;
502 case 4: *info = (mb->type_ == 1) ? it->preds_[0] : 0xff; break;
503 case 5: *info = mb->uv_mode_; break;
504 case 6: {
505 const int b = (int)((it->luma_bits_ + it->uv_bits_ + 7) >> 3);
506 *info = (b > 255) ? 255 : b; break;
507 }
508 case 7: *info = mb->alpha_; break;
509 default: *info = 0; break;
510 }
511 }
512#if SEGMENT_VISU // visualize segments and prediction modes
513 SetBlock(it->yuv_out_ + Y_OFF_ENC, mb->segment_ * 64, 16);
514 SetBlock(it->yuv_out_ + U_OFF_ENC, it->preds_[0] * 64, 8);
515 SetBlock(it->yuv_out_ + V_OFF_ENC, mb->uv_mode_ * 64, 8);
516#endif
517}
518
519static double GetPSNR(uint64_t mse, uint64_t size) {
520 return (mse > 0 && size > 0) ? 10. * log10(255. * 255. * size / mse) : 99;
521}
522
523//------------------------------------------------------------------------------
524// StatLoop(): only collect statistics (number of skips, token usage, ...).
525// This is used for deciding optimal probabilities. It also modifies the
526// quantizer value if some target (size, PSNR) was specified.
527
528static void SetLoopParams(VP8Encoder* const enc, float q) {
529 // Make sure the quality parameter is inside valid bounds
530 q = Clamp(q, 0.f, 100.f);
531
532 VP8SetSegmentParams(enc, q); // setup segment quantizations and filters
533 SetSegmentProbas(enc); // compute segment probabilities
534
535 ResetStats(enc);
536 ResetSSE(enc);
537}
538
539static uint64_t OneStatPass(VP8Encoder* const enc, VP8RDLevel rd_opt,
540 int nb_mbs, int percent_delta,
541 PassStats* const s) {
542 VP8EncIterator it;
543 uint64_t size = 0;
544 uint64_t size_p0 = 0;
545 uint64_t distortion = 0;
546 const uint64_t pixel_count = nb_mbs * 384;
547
548 VP8IteratorInit(enc, &it);
549 SetLoopParams(enc, s->q);
550 do {
551 VP8ModeScore info;
552 VP8IteratorImport(&it, NULL);
553 if (VP8Decimate(&it, &info, rd_opt)) {
554 // Just record the number of skips and act like skip_proba is not used.
555 enc->proba_.nb_skip_++;
556 }
557 RecordResiduals(&it, &info);
558 size += info.R + info.H;
559 size_p0 += info.H;
560 distortion += info.D;
561 if (percent_delta && !VP8IteratorProgress(&it, percent_delta)) {
562 return 0;
563 }
564 VP8IteratorSaveBoundary(&it);
565 } while (VP8IteratorNext(&it) && --nb_mbs > 0);
566
567 size_p0 += enc->segment_hdr_.size_;
568 if (s->do_size_search) {
569 size += FinalizeSkipProba(enc);
570 size += FinalizeTokenProbas(&enc->proba_);
571 size = ((size + size_p0 + 1024) >> 11) + HEADER_SIZE_ESTIMATE;
572 s->value = (double)size;
573 } else {
574 s->value = GetPSNR(distortion, pixel_count);
575 }
576 return size_p0;
577}
578
579static int StatLoop(VP8Encoder* const enc) {
580 const int method = enc->method_;
581 const int do_search = enc->do_search_;
582 const int fast_probe = ((method == 0 || method == 3) && !do_search);
583 int num_pass_left = enc->config_->pass;
584 const int task_percent = 20;
585 const int percent_per_pass =
586 (task_percent + num_pass_left / 2) / num_pass_left;
587 const int final_percent = enc->percent_ + task_percent;
588 const VP8RDLevel rd_opt =
589 (method >= 3 || do_search) ? RD_OPT_BASIC : RD_OPT_NONE;
590 int nb_mbs = enc->mb_w_ * enc->mb_h_;
591 PassStats stats;
592
593 InitPassStats(enc, &stats);
594 ResetTokenStats(enc);
595
596 // Fast mode: quick analysis pass over few mbs. Better than nothing.
597 if (fast_probe) {
598 if (method == 3) { // we need more stats for method 3 to be reliable.
599 nb_mbs = (nb_mbs > 200) ? nb_mbs >> 1 : 100;
600 } else {
601 nb_mbs = (nb_mbs > 200) ? nb_mbs >> 2 : 50;
602 }
603 }
604
605 while (num_pass_left-- > 0) {
606 const int is_last_pass = (fabs(stats.dq) <= DQ_LIMIT) ||
607 (num_pass_left == 0) ||
608 (enc->max_i4_header_bits_ == 0);
609 const uint64_t size_p0 =
610 OneStatPass(enc, rd_opt, nb_mbs, percent_per_pass, &stats);
611 if (size_p0 == 0) return 0;
612#if (DEBUG_SEARCH > 0)
613 printf("#%d value:%.1lf -> %.1lf q:%.2f -> %.2f\n",
614 num_pass_left, stats.last_value, stats.value, stats.last_q, stats.q);
615#endif
616 if (enc->max_i4_header_bits_ > 0 && size_p0 > PARTITION0_SIZE_LIMIT) {
617 ++num_pass_left;
618 enc->max_i4_header_bits_ >>= 1; // strengthen header bit limitation...
619 continue; // ...and start over
620 }
621 if (is_last_pass) {
622 break;
623 }
624 // If no target size: just do several pass without changing 'q'
625 if (do_search) {
626 ComputeNextQ(&stats);
627 if (fabs(stats.dq) <= DQ_LIMIT) break;
628 }
629 }
630 if (!do_search || !stats.do_size_search) {
631 // Need to finalize probas now, since it wasn't done during the search.
632 FinalizeSkipProba(enc);
633 FinalizeTokenProbas(&enc->proba_);
634 }
635 VP8CalculateLevelCosts(&enc->proba_); // finalize costs
636 return WebPReportProgress(enc->pic_, final_percent, &enc->percent_);
637}
638
639//------------------------------------------------------------------------------
640// Main loops
641//
642
643static const int kAverageBytesPerMB[8] = { 50, 24, 16, 9, 7, 5, 3, 2 };
644
645static int PreLoopInitialize(VP8Encoder* const enc) {
646 int p;
647 int ok = 1;
648 const int average_bytes_per_MB = kAverageBytesPerMB[enc->base_quant_ >> 4];
649 const int bytes_per_parts =
650 enc->mb_w_ * enc->mb_h_ * average_bytes_per_MB / enc->num_parts_;
651 // Initialize the bit-writers
652 for (p = 0; ok && p < enc->num_parts_; ++p) {
653 ok = VP8BitWriterInit(enc->parts_ + p, bytes_per_parts);
654 }
655 if (!ok) {
656 VP8EncFreeBitWriters(enc); // malloc error occurred
657 WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY);
658 }
659 return ok;
660}
661
662static int PostLoopFinalize(VP8EncIterator* const it, int ok) {
663 VP8Encoder* const enc = it->enc_;
664 if (ok) { // Finalize the partitions, check for extra errors.
665 int p;
666 for (p = 0; p < enc->num_parts_; ++p) {
667 VP8BitWriterFinish(enc->parts_ + p);
668 ok &= !enc->parts_[p].error_;
669 }
670 }
671
672 if (ok) { // All good. Finish up.
673 if (enc->pic_->stats != NULL) { // finalize byte counters...
674 int i, s;
675 for (i = 0; i <= 2; ++i) {
676 for (s = 0; s < NUM_MB_SEGMENTS; ++s) {
677 enc->residual_bytes_[i][s] = (int)((it->bit_count_[s][i] + 7) >> 3);
678 }
679 }
680 }
681 VP8AdjustFilterStrength(it); // ...and store filter stats.
682 } else {
683 // Something bad happened -> need to do some memory cleanup.
684 VP8EncFreeBitWriters(enc);
685 }
686 return ok;
687}
688
689//------------------------------------------------------------------------------
690// VP8EncLoop(): does the final bitstream coding.
691
692static void ResetAfterSkip(VP8EncIterator* const it) {
693 if (it->mb_->type_ == 1) {
694 *it->nz_ = 0; // reset all predictors
695 it->left_nz_[8] = 0;
696 } else {
697 *it->nz_ &= (1 << 24); // preserve the dc_nz bit
698 }
699}
700
701int VP8EncLoop(VP8Encoder* const enc) {
702 VP8EncIterator it;
703 int ok = PreLoopInitialize(enc);
704 if (!ok) return 0;
705
706 StatLoop(enc); // stats-collection loop
707
708 VP8IteratorInit(enc, &it);
709 VP8InitFilter(&it);
710 do {
711 VP8ModeScore info;
712 const int dont_use_skip = !enc->proba_.use_skip_proba_;
713 const VP8RDLevel rd_opt = enc->rd_opt_level_;
714
715 VP8IteratorImport(&it, NULL);
716 // Warning! order is important: first call VP8Decimate() and
717 // *then* decide how to code the skip decision if there's one.
718 if (!VP8Decimate(&it, &info, rd_opt) || dont_use_skip) {
719 CodeResiduals(it.bw_, &it, &info);
720 } else { // reset predictors after a skip
721 ResetAfterSkip(&it);
722 }
723 StoreSideInfo(&it);
724 VP8StoreFilterStats(&it);
725 VP8IteratorExport(&it);
726 ok = VP8IteratorProgress(&it, 20);
727 VP8IteratorSaveBoundary(&it);
728 } while (ok && VP8IteratorNext(&it));
729
730 return PostLoopFinalize(&it, ok);
731}
732
733//------------------------------------------------------------------------------
734// Single pass using Token Buffer.
735
736#if !defined(DISABLE_TOKEN_BUFFER)
737
738#define MIN_COUNT 96 // minimum number of macroblocks before updating stats
739
740int VP8EncTokenLoop(VP8Encoder* const enc) {
741 // Roughly refresh the proba eight times per pass
742 int max_count = (enc->mb_w_ * enc->mb_h_) >> 3;
743 int num_pass_left = enc->config_->pass;
744 const int do_search = enc->do_search_;
745 VP8EncIterator it;
746 VP8EncProba* const proba = &enc->proba_;
747 const VP8RDLevel rd_opt = enc->rd_opt_level_;
748 const uint64_t pixel_count = enc->mb_w_ * enc->mb_h_ * 384;
749 PassStats stats;
750 int ok;
751
752 InitPassStats(enc, &stats);
753 ok = PreLoopInitialize(enc);
754 if (!ok) return 0;
755
756 if (max_count < MIN_COUNT) max_count = MIN_COUNT;
757
758 assert(enc->num_parts_ == 1);
759 assert(enc->use_tokens_);
760 assert(proba->use_skip_proba_ == 0);
761 assert(rd_opt >= RD_OPT_BASIC); // otherwise, token-buffer won't be useful
762 assert(num_pass_left > 0);
763
764 while (ok && num_pass_left-- > 0) {
765 const int is_last_pass = (fabs(stats.dq) <= DQ_LIMIT) ||
766 (num_pass_left == 0) ||
767 (enc->max_i4_header_bits_ == 0);
768 uint64_t size_p0 = 0;
769 uint64_t distortion = 0;
770 int cnt = max_count;
771 VP8IteratorInit(enc, &it);
772 SetLoopParams(enc, stats.q);
773 if (is_last_pass) {
774 ResetTokenStats(enc);
775 VP8InitFilter(&it); // don't collect stats until last pass (too costly)
776 }
777 VP8TBufferClear(&enc->tokens_);
778 do {
779 VP8ModeScore info;
780 VP8IteratorImport(&it, NULL);
781 if (--cnt < 0) {
782 FinalizeTokenProbas(proba);
783 VP8CalculateLevelCosts(proba); // refresh cost tables for rd-opt
784 cnt = max_count;
785 }
786 VP8Decimate(&it, &info, rd_opt);
787 ok = RecordTokens(&it, &info, &enc->tokens_);
788 if (!ok) {
789 WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY);
790 break;
791 }
792 size_p0 += info.H;
793 distortion += info.D;
794 if (is_last_pass) {
795 StoreSideInfo(&it);
796 VP8StoreFilterStats(&it);
797 VP8IteratorExport(&it);
798 ok = VP8IteratorProgress(&it, 20);
799 }
800 VP8IteratorSaveBoundary(&it);
801 } while (ok && VP8IteratorNext(&it));
802 if (!ok) break;
803
804 size_p0 += enc->segment_hdr_.size_;
805 if (stats.do_size_search) {
806 uint64_t size = FinalizeTokenProbas(&enc->proba_);
807 size += VP8EstimateTokenSize(&enc->tokens_,
808 (const uint8_t*)proba->coeffs_);
809 size = (size + size_p0 + 1024) >> 11; // -> size in bytes
810 size += HEADER_SIZE_ESTIMATE;
811 stats.value = (double)size;
812 } else { // compute and store PSNR
813 stats.value = GetPSNR(distortion, pixel_count);
814 }
815
816#if (DEBUG_SEARCH > 0)
817 printf("#%2d metric:%.1lf -> %.1lf last_q=%.2lf q=%.2lf dq=%.2lf\n",
818 num_pass_left, stats.last_value, stats.value,
819 stats.last_q, stats.q, stats.dq);
820#endif
821 if (enc->max_i4_header_bits_ > 0 && size_p0 > PARTITION0_SIZE_LIMIT) {
822 ++num_pass_left;
823 enc->max_i4_header_bits_ >>= 1; // strengthen header bit limitation...
824 continue; // ...and start over
825 }
826 if (is_last_pass) {
827 break; // done
828 }
829 if (do_search) {
830 ComputeNextQ(&stats); // Adjust q
831 }
832 }
833 if (ok) {
834 if (!stats.do_size_search) {
835 FinalizeTokenProbas(&enc->proba_);
836 }
837 ok = VP8EmitTokens(&enc->tokens_, enc->parts_ + 0,
838 (const uint8_t*)proba->coeffs_, 1);
839 }
840 ok = ok && WebPReportProgress(enc->pic_, enc->percent_ + 20, &enc->percent_);
841 return PostLoopFinalize(&it, ok);
842}
843
844#else
845
846int VP8EncTokenLoop(VP8Encoder* const enc) {
847 (void)enc;
848 return 0; // we shouldn't be here.
849}
850
851#endif // DISABLE_TOKEN_BUFFER
852
853//------------------------------------------------------------------------------
854
855