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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 // WebP encoder: main entry point
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13 
14 #include <assert.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <math.h>
18 
19 #include "./cost.h"
20 #include "./vp8enci.h"
21 #include "./vp8li.h"
22 #include "../utils/utils.h"
23 
24 // #define PRINT_MEMORY_INFO
25 
26 #ifdef PRINT_MEMORY_INFO
27 #include <stdio.h>
28 #endif
29 
30 //------------------------------------------------------------------------------
31 
WebPGetEncoderVersion(void)32 int WebPGetEncoderVersion(void) {
33   return (ENC_MAJ_VERSION << 16) | (ENC_MIN_VERSION << 8) | ENC_REV_VERSION;
34 }
35 
36 //------------------------------------------------------------------------------
37 // VP8Encoder
38 //------------------------------------------------------------------------------
39 
ResetSegmentHeader(VP8Encoder * const enc)40 static void ResetSegmentHeader(VP8Encoder* const enc) {
41   VP8EncSegmentHeader* const hdr = &enc->segment_hdr_;
42   hdr->num_segments_ = enc->config_->segments;
43   hdr->update_map_  = (hdr->num_segments_ > 1);
44   hdr->size_ = 0;
45 }
46 
ResetFilterHeader(VP8Encoder * const enc)47 static void ResetFilterHeader(VP8Encoder* const enc) {
48   VP8EncFilterHeader* const hdr = &enc->filter_hdr_;
49   hdr->simple_ = 1;
50   hdr->level_ = 0;
51   hdr->sharpness_ = 0;
52   hdr->i4x4_lf_delta_ = 0;
53 }
54 
ResetBoundaryPredictions(VP8Encoder * const enc)55 static void ResetBoundaryPredictions(VP8Encoder* const enc) {
56   // init boundary values once for all
57   // Note: actually, initializing the preds_[] is only needed for intra4.
58   int i;
59   uint8_t* const top = enc->preds_ - enc->preds_w_;
60   uint8_t* const left = enc->preds_ - 1;
61   for (i = -1; i < 4 * enc->mb_w_; ++i) {
62     top[i] = B_DC_PRED;
63   }
64   for (i = 0; i < 4 * enc->mb_h_; ++i) {
65     left[i * enc->preds_w_] = B_DC_PRED;
66   }
67   enc->nz_[-1] = 0;   // constant
68 }
69 
70 // Mapping from config->method_ to coding tools used.
71 //-------------------+---+---+---+---+---+---+---+
72 //   Method          | 0 | 1 | 2 | 3 |(4)| 5 | 6 |
73 //-------------------+---+---+---+---+---+---+---+
74 // fast probe        | x |   |   | x |   |   |   |
75 //-------------------+---+---+---+---+---+---+---+
76 // dynamic proba     | ~ | x | x | x | x | x | x |
77 //-------------------+---+---+---+---+---+---+---+
78 // fast mode analysis|   |   |   |   | x | x | x |
79 //-------------------+---+---+---+---+---+---+---+
80 // basic rd-opt      |   |   |   | x | x | x | x |
81 //-------------------+---+---+---+---+---+---+---+
82 // disto-refine i4/16| x | x | x |   |   |   |   |
83 //-------------------+---+---+---+---+---+---+---+
84 // disto-refine uv   |   | x | x |   |   |   |   |
85 //-------------------+---+---+---+---+---+---+---+
86 // rd-opt i4/16      |   |   | ~ | x | x | x | x |
87 //-------------------+---+---+---+---+---+---+---+
88 // token buffer (opt)|   |   |   | x | x | x | x |
89 //-------------------+---+---+---+---+---+---+---+
90 // Trellis           |   |   |   |   |   | x |Ful|
91 //-------------------+---+---+---+---+---+---+---+
92 // full-SNS          |   |   |   |   | x | x | x |
93 //-------------------+---+---+---+---+---+---+---+
94 
MapConfigToTools(VP8Encoder * const enc)95 static void MapConfigToTools(VP8Encoder* const enc) {
96   const WebPConfig* const config = enc->config_;
97   const int method = config->method;
98   const int limit = 100 - config->partition_limit;
99   enc->method_ = method;
100   enc->rd_opt_level_ = (method >= 6) ? RD_OPT_TRELLIS_ALL
101                      : (method >= 5) ? RD_OPT_TRELLIS
102                      : (method >= 3) ? RD_OPT_BASIC
103                      : RD_OPT_NONE;
104   enc->max_i4_header_bits_ =
105       256 * 16 * 16 *                 // upper bound: up to 16bit per 4x4 block
106       (limit * limit) / (100 * 100);  // ... modulated with a quadratic curve.
107 
108   enc->thread_level_ = config->thread_level;
109 
110   enc->do_search_ = (config->target_size > 0 || config->target_PSNR > 0);
111   if (!config->low_memory) {
112 #if !defined(DISABLE_TOKEN_BUFFER)
113     enc->use_tokens_ = (enc->rd_opt_level_ >= RD_OPT_BASIC);  // need rd stats
114 #endif
115     if (enc->use_tokens_) {
116       enc->num_parts_ = 1;   // doesn't work with multi-partition
117     }
118   }
119 }
120 
121 // Memory scaling with dimensions:
122 //  memory (bytes) ~= 2.25 * w + 0.0625 * w * h
123 //
124 // Typical memory footprint (614x440 picture)
125 //              encoder: 22111
126 //                 info: 4368
127 //                preds: 17741
128 //          top samples: 1263
129 //             non-zero: 175
130 //             lf-stats: 0
131 //                total: 45658
132 // Transient object sizes:
133 //       VP8EncIterator: 3360
134 //         VP8ModeScore: 872
135 //       VP8SegmentInfo: 732
136 //          VP8EncProba: 18352
137 //              LFStats: 2048
138 // Picture size (yuv): 419328
139 
InitVP8Encoder(const WebPConfig * const config,WebPPicture * const picture)140 static VP8Encoder* InitVP8Encoder(const WebPConfig* const config,
141                                   WebPPicture* const picture) {
142   VP8Encoder* enc;
143   const int use_filter =
144       (config->filter_strength > 0) || (config->autofilter > 0);
145   const int mb_w = (picture->width + 15) >> 4;
146   const int mb_h = (picture->height + 15) >> 4;
147   const int preds_w = 4 * mb_w + 1;
148   const int preds_h = 4 * mb_h + 1;
149   const size_t preds_size = preds_w * preds_h * sizeof(*enc->preds_);
150   const int top_stride = mb_w * 16;
151   const size_t nz_size = (mb_w + 1) * sizeof(*enc->nz_) + WEBP_ALIGN_CST;
152   const size_t info_size = mb_w * mb_h * sizeof(*enc->mb_info_);
153   const size_t samples_size =
154       2 * top_stride * sizeof(*enc->y_top_)  // top-luma/u/v
155       + WEBP_ALIGN_CST;                      // align all
156   const size_t lf_stats_size =
157       config->autofilter ? sizeof(*enc->lf_stats_) + WEBP_ALIGN_CST : 0;
158   uint8_t* mem;
159   const uint64_t size = (uint64_t)sizeof(*enc)   // main struct
160                       + WEBP_ALIGN_CST           // cache alignment
161                       + info_size                // modes info
162                       + preds_size               // prediction modes
163                       + samples_size             // top/left samples
164                       + nz_size                  // coeff context bits
165                       + lf_stats_size;           // autofilter stats
166 
167 #ifdef PRINT_MEMORY_INFO
168   printf("===================================\n");
169   printf("Memory used:\n"
170          "             encoder: %ld\n"
171          "                info: %ld\n"
172          "               preds: %ld\n"
173          "         top samples: %ld\n"
174          "            non-zero: %ld\n"
175          "            lf-stats: %ld\n"
176          "               total: %ld\n",
177          sizeof(*enc) + WEBP_ALIGN_CST, info_size,
178          preds_size, samples_size, nz_size, lf_stats_size, size);
179   printf("Transient object sizes:\n"
180          "      VP8EncIterator: %ld\n"
181          "        VP8ModeScore: %ld\n"
182          "      VP8SegmentInfo: %ld\n"
183          "         VP8EncProba: %ld\n"
184          "             LFStats: %ld\n",
185          sizeof(VP8EncIterator), sizeof(VP8ModeScore),
186          sizeof(VP8SegmentInfo), sizeof(VP8EncProba),
187          sizeof(LFStats));
188   printf("Picture size (yuv): %ld\n",
189          mb_w * mb_h * 384 * sizeof(uint8_t));
190   printf("===================================\n");
191 #endif
192   mem = (uint8_t*)WebPSafeMalloc(size, sizeof(*mem));
193   if (mem == NULL) {
194     WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
195     return NULL;
196   }
197   enc = (VP8Encoder*)mem;
198   mem = (uint8_t*)WEBP_ALIGN(mem + sizeof(*enc));
199   memset(enc, 0, sizeof(*enc));
200   enc->num_parts_ = 1 << config->partitions;
201   enc->mb_w_ = mb_w;
202   enc->mb_h_ = mb_h;
203   enc->preds_w_ = preds_w;
204   enc->mb_info_ = (VP8MBInfo*)mem;
205   mem += info_size;
206   enc->preds_ = ((uint8_t*)mem) + 1 + enc->preds_w_;
207   mem += preds_size;
208   enc->nz_ = 1 + (uint32_t*)WEBP_ALIGN(mem);
209   mem += nz_size;
210   enc->lf_stats_ = lf_stats_size ? (LFStats*)WEBP_ALIGN(mem) : NULL;
211   mem += lf_stats_size;
212 
213   // top samples (all 16-aligned)
214   mem = (uint8_t*)WEBP_ALIGN(mem);
215   enc->y_top_ = (uint8_t*)mem;
216   enc->uv_top_ = enc->y_top_ + top_stride;
217   mem += 2 * top_stride;
218   assert(mem <= (uint8_t*)enc + size);
219 
220   enc->config_ = config;
221   enc->profile_ = use_filter ? ((config->filter_type == 1) ? 0 : 1) : 2;
222   enc->pic_ = picture;
223   enc->percent_ = 0;
224 
225   MapConfigToTools(enc);
226   VP8EncDspInit();
227   VP8DefaultProbas(enc);
228   ResetSegmentHeader(enc);
229   ResetFilterHeader(enc);
230   ResetBoundaryPredictions(enc);
231   VP8EncDspCostInit();
232   VP8EncInitAlpha(enc);
233 
234   // lower quality means smaller output -> we modulate a little the page
235   // size based on quality. This is just a crude 1rst-order prediction.
236   {
237     const float scale = 1.f + config->quality * 5.f / 100.f;  // in [1,6]
238     VP8TBufferInit(&enc->tokens_, (int)(mb_w * mb_h * 4 * scale));
239   }
240   return enc;
241 }
242 
DeleteVP8Encoder(VP8Encoder * enc)243 static int DeleteVP8Encoder(VP8Encoder* enc) {
244   int ok = 1;
245   if (enc != NULL) {
246     ok = VP8EncDeleteAlpha(enc);
247     VP8TBufferClear(&enc->tokens_);
248     WebPSafeFree(enc);
249   }
250   return ok;
251 }
252 
253 //------------------------------------------------------------------------------
254 
GetPSNR(uint64_t err,uint64_t size)255 static double GetPSNR(uint64_t err, uint64_t size) {
256   return (err > 0 && size > 0) ? 10. * log10(255. * 255. * size / err) : 99.;
257 }
258 
FinalizePSNR(const VP8Encoder * const enc)259 static void FinalizePSNR(const VP8Encoder* const enc) {
260   WebPAuxStats* stats = enc->pic_->stats;
261   const uint64_t size = enc->sse_count_;
262   const uint64_t* const sse = enc->sse_;
263   stats->PSNR[0] = (float)GetPSNR(sse[0], size);
264   stats->PSNR[1] = (float)GetPSNR(sse[1], size / 4);
265   stats->PSNR[2] = (float)GetPSNR(sse[2], size / 4);
266   stats->PSNR[3] = (float)GetPSNR(sse[0] + sse[1] + sse[2], size * 3 / 2);
267   stats->PSNR[4] = (float)GetPSNR(sse[3], size);
268 }
269 
StoreStats(VP8Encoder * const enc)270 static void StoreStats(VP8Encoder* const enc) {
271   WebPAuxStats* const stats = enc->pic_->stats;
272   if (stats != NULL) {
273     int i, s;
274     for (i = 0; i < NUM_MB_SEGMENTS; ++i) {
275       stats->segment_level[i] = enc->dqm_[i].fstrength_;
276       stats->segment_quant[i] = enc->dqm_[i].quant_;
277       for (s = 0; s <= 2; ++s) {
278         stats->residual_bytes[s][i] = enc->residual_bytes_[s][i];
279       }
280     }
281     FinalizePSNR(enc);
282     stats->coded_size = enc->coded_size_;
283     for (i = 0; i < 3; ++i) {
284       stats->block_count[i] = enc->block_count_[i];
285     }
286   }
287   WebPReportProgress(enc->pic_, 100, &enc->percent_);  // done!
288 }
289 
WebPEncodingSetError(const WebPPicture * const pic,WebPEncodingError error)290 int WebPEncodingSetError(const WebPPicture* const pic,
291                          WebPEncodingError error) {
292   assert((int)error < VP8_ENC_ERROR_LAST);
293   assert((int)error >= VP8_ENC_OK);
294   ((WebPPicture*)pic)->error_code = error;
295   return 0;
296 }
297 
WebPReportProgress(const WebPPicture * const pic,int percent,int * const percent_store)298 int WebPReportProgress(const WebPPicture* const pic,
299                        int percent, int* const percent_store) {
300   if (percent_store != NULL && percent != *percent_store) {
301     *percent_store = percent;
302     if (pic->progress_hook && !pic->progress_hook(percent, pic)) {
303       // user abort requested
304       WebPEncodingSetError(pic, VP8_ENC_ERROR_USER_ABORT);
305       return 0;
306     }
307   }
308   return 1;  // ok
309 }
310 //------------------------------------------------------------------------------
311 
WebPEncode(const WebPConfig * config,WebPPicture * pic)312 int WebPEncode(const WebPConfig* config, WebPPicture* pic) {
313   int ok = 0;
314 
315   if (pic == NULL)
316     return 0;
317   WebPEncodingSetError(pic, VP8_ENC_OK);  // all ok so far
318   if (config == NULL)  // bad params
319     return WebPEncodingSetError(pic, VP8_ENC_ERROR_NULL_PARAMETER);
320   if (!WebPValidateConfig(config))
321     return WebPEncodingSetError(pic, VP8_ENC_ERROR_INVALID_CONFIGURATION);
322   if (pic->width <= 0 || pic->height <= 0)
323     return WebPEncodingSetError(pic, VP8_ENC_ERROR_BAD_DIMENSION);
324   if (pic->width > WEBP_MAX_DIMENSION || pic->height > WEBP_MAX_DIMENSION)
325     return WebPEncodingSetError(pic, VP8_ENC_ERROR_BAD_DIMENSION);
326 
327   if (pic->stats != NULL) memset(pic->stats, 0, sizeof(*pic->stats));
328 
329   if (!config->lossless) {
330     VP8Encoder* enc = NULL;
331 
332     if (!config->exact) {
333       WebPCleanupTransparentArea(pic);
334     }
335 
336     if (pic->use_argb || pic->y == NULL || pic->u == NULL || pic->v == NULL) {
337       // Make sure we have YUVA samples.
338       if (config->preprocessing & 4) {
339         if (!WebPPictureSmartARGBToYUVA(pic)) {
340           return 0;
341         }
342       } else {
343         float dithering = 0.f;
344         if (config->preprocessing & 2) {
345           const float x = config->quality / 100.f;
346           const float x2 = x * x;
347           // slowly decreasing from max dithering at low quality (q->0)
348           // to 0.5 dithering amplitude at high quality (q->100)
349           dithering = 1.0f + (0.5f - 1.0f) * x2 * x2;
350         }
351         if (!WebPPictureARGBToYUVADithered(pic, WEBP_YUV420, dithering)) {
352           return 0;
353         }
354       }
355     }
356 
357     enc = InitVP8Encoder(config, pic);
358     if (enc == NULL) return 0;  // pic->error is already set.
359     // Note: each of the tasks below account for 20% in the progress report.
360     ok = VP8EncAnalyze(enc);
361 
362     // Analysis is done, proceed to actual coding.
363     ok = ok && VP8EncStartAlpha(enc);   // possibly done in parallel
364     if (!enc->use_tokens_) {
365       ok = ok && VP8EncLoop(enc);
366     } else {
367       ok = ok && VP8EncTokenLoop(enc);
368     }
369     ok = ok && VP8EncFinishAlpha(enc);
370 
371     ok = ok && VP8EncWrite(enc);
372     StoreStats(enc);
373     if (!ok) {
374       VP8EncFreeBitWriters(enc);
375     }
376     ok &= DeleteVP8Encoder(enc);  // must always be called, even if !ok
377   } else {
378     // Make sure we have ARGB samples.
379     if (pic->argb == NULL && !WebPPictureYUVAToARGB(pic)) {
380       return 0;
381     }
382 
383     if (!config->exact) {
384       WebPCleanupTransparentAreaLossless(pic);
385     }
386 
387     ok = VP8LEncodeImage(config, pic);  // Sets pic->error in case of problem.
388   }
389 
390   return ok;
391 }
392