1 // Copyright 2012 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 // main entry for the lossless encoder.
11 //
12 // Author: Vikas Arora (vikaas.arora@gmail.com)
13 //
14
15 #include <assert.h>
16 #include <stdlib.h>
17
18 #include "src/enc/backward_references_enc.h"
19 #include "src/enc/histogram_enc.h"
20 #include "src/enc/vp8i_enc.h"
21 #include "src/enc/vp8li_enc.h"
22 #include "src/dsp/lossless.h"
23 #include "src/dsp/lossless_common.h"
24 #include "src/utils/bit_writer_utils.h"
25 #include "src/utils/huffman_encode_utils.h"
26 #include "src/utils/utils.h"
27 #include "src/webp/format_constants.h"
28
29 // Maximum number of histogram images (sub-blocks).
30 #define MAX_HUFF_IMAGE_SIZE 2600
31
32 // Palette reordering for smaller sum of deltas (and for smaller storage).
33
PaletteCompareColorsForQsort(const void * p1,const void * p2)34 static int PaletteCompareColorsForQsort(const void* p1, const void* p2) {
35 const uint32_t a = WebPMemToUint32((uint8_t*)p1);
36 const uint32_t b = WebPMemToUint32((uint8_t*)p2);
37 assert(a != b);
38 return (a < b) ? -1 : 1;
39 }
40
PaletteComponentDistance(uint32_t v)41 static WEBP_INLINE uint32_t PaletteComponentDistance(uint32_t v) {
42 return (v <= 128) ? v : (256 - v);
43 }
44
45 // Computes a value that is related to the entropy created by the
46 // palette entry diff.
47 //
48 // Note that the last & 0xff is a no-operation in the next statement, but
49 // removed by most compilers and is here only for regularity of the code.
PaletteColorDistance(uint32_t col1,uint32_t col2)50 static WEBP_INLINE uint32_t PaletteColorDistance(uint32_t col1, uint32_t col2) {
51 const uint32_t diff = VP8LSubPixels(col1, col2);
52 const int kMoreWeightForRGBThanForAlpha = 9;
53 uint32_t score;
54 score = PaletteComponentDistance((diff >> 0) & 0xff);
55 score += PaletteComponentDistance((diff >> 8) & 0xff);
56 score += PaletteComponentDistance((diff >> 16) & 0xff);
57 score *= kMoreWeightForRGBThanForAlpha;
58 score += PaletteComponentDistance((diff >> 24) & 0xff);
59 return score;
60 }
61
SwapColor(uint32_t * const col1,uint32_t * const col2)62 static WEBP_INLINE void SwapColor(uint32_t* const col1, uint32_t* const col2) {
63 const uint32_t tmp = *col1;
64 *col1 = *col2;
65 *col2 = tmp;
66 }
67
GreedyMinimizeDeltas(uint32_t palette[],int num_colors)68 static void GreedyMinimizeDeltas(uint32_t palette[], int num_colors) {
69 // Find greedily always the closest color of the predicted color to minimize
70 // deltas in the palette. This reduces storage needs since the
71 // palette is stored with delta encoding.
72 uint32_t predict = 0x00000000;
73 int i, k;
74 for (i = 0; i < num_colors; ++i) {
75 int best_ix = i;
76 uint32_t best_score = ~0U;
77 for (k = i; k < num_colors; ++k) {
78 const uint32_t cur_score = PaletteColorDistance(palette[k], predict);
79 if (best_score > cur_score) {
80 best_score = cur_score;
81 best_ix = k;
82 }
83 }
84 SwapColor(&palette[best_ix], &palette[i]);
85 predict = palette[i];
86 }
87 }
88
89 // The palette has been sorted by alpha. This function checks if the other
90 // components of the palette have a monotonic development with regards to
91 // position in the palette. If all have monotonic development, there is
92 // no benefit to re-organize them greedily. A monotonic development
93 // would be spotted in green-only situations (like lossy alpha) or gray-scale
94 // images.
PaletteHasNonMonotonousDeltas(uint32_t palette[],int num_colors)95 static int PaletteHasNonMonotonousDeltas(uint32_t palette[], int num_colors) {
96 uint32_t predict = 0x000000;
97 int i;
98 uint8_t sign_found = 0x00;
99 for (i = 0; i < num_colors; ++i) {
100 const uint32_t diff = VP8LSubPixels(palette[i], predict);
101 const uint8_t rd = (diff >> 16) & 0xff;
102 const uint8_t gd = (diff >> 8) & 0xff;
103 const uint8_t bd = (diff >> 0) & 0xff;
104 if (rd != 0x00) {
105 sign_found |= (rd < 0x80) ? 1 : 2;
106 }
107 if (gd != 0x00) {
108 sign_found |= (gd < 0x80) ? 8 : 16;
109 }
110 if (bd != 0x00) {
111 sign_found |= (bd < 0x80) ? 64 : 128;
112 }
113 predict = palette[i];
114 }
115 return (sign_found & (sign_found << 1)) != 0; // two consequent signs.
116 }
117
118 // -----------------------------------------------------------------------------
119 // Palette
120
121 // If number of colors in the image is less than or equal to MAX_PALETTE_SIZE,
122 // creates a palette and returns true, else returns false.
AnalyzeAndCreatePalette(const WebPPicture * const pic,int low_effort,uint32_t palette[MAX_PALETTE_SIZE],int * const palette_size)123 static int AnalyzeAndCreatePalette(const WebPPicture* const pic,
124 int low_effort,
125 uint32_t palette[MAX_PALETTE_SIZE],
126 int* const palette_size) {
127 const int num_colors = WebPGetColorPalette(pic, palette);
128 if (num_colors > MAX_PALETTE_SIZE) {
129 *palette_size = 0;
130 return 0;
131 }
132 *palette_size = num_colors;
133 qsort(palette, num_colors, sizeof(*palette), PaletteCompareColorsForQsort);
134 if (!low_effort && PaletteHasNonMonotonousDeltas(palette, num_colors)) {
135 GreedyMinimizeDeltas(palette, num_colors);
136 }
137 return 1;
138 }
139
140 // These five modes are evaluated and their respective entropy is computed.
141 typedef enum {
142 kDirect = 0,
143 kSpatial = 1,
144 kSubGreen = 2,
145 kSpatialSubGreen = 3,
146 kPalette = 4,
147 kPaletteAndSpatial = 5,
148 kNumEntropyIx = 6
149 } EntropyIx;
150
151 typedef enum {
152 kHistoAlpha = 0,
153 kHistoAlphaPred,
154 kHistoGreen,
155 kHistoGreenPred,
156 kHistoRed,
157 kHistoRedPred,
158 kHistoBlue,
159 kHistoBluePred,
160 kHistoRedSubGreen,
161 kHistoRedPredSubGreen,
162 kHistoBlueSubGreen,
163 kHistoBluePredSubGreen,
164 kHistoPalette,
165 kHistoTotal // Must be last.
166 } HistoIx;
167
AddSingleSubGreen(int p,uint32_t * const r,uint32_t * const b)168 static void AddSingleSubGreen(int p, uint32_t* const r, uint32_t* const b) {
169 const int green = p >> 8; // The upper bits are masked away later.
170 ++r[((p >> 16) - green) & 0xff];
171 ++b[((p >> 0) - green) & 0xff];
172 }
173
AddSingle(uint32_t p,uint32_t * const a,uint32_t * const r,uint32_t * const g,uint32_t * const b)174 static void AddSingle(uint32_t p,
175 uint32_t* const a, uint32_t* const r,
176 uint32_t* const g, uint32_t* const b) {
177 ++a[(p >> 24) & 0xff];
178 ++r[(p >> 16) & 0xff];
179 ++g[(p >> 8) & 0xff];
180 ++b[(p >> 0) & 0xff];
181 }
182
HashPix(uint32_t pix)183 static WEBP_INLINE uint32_t HashPix(uint32_t pix) {
184 // Note that masking with 0xffffffffu is for preventing an
185 // 'unsigned int overflow' warning. Doesn't impact the compiled code.
186 return ((((uint64_t)pix + (pix >> 19)) * 0x39c5fba7ull) & 0xffffffffu) >> 24;
187 }
188
AnalyzeEntropy(const uint32_t * argb,int width,int height,int argb_stride,int use_palette,int palette_size,int transform_bits,EntropyIx * const min_entropy_ix,int * const red_and_blue_always_zero)189 static int AnalyzeEntropy(const uint32_t* argb,
190 int width, int height, int argb_stride,
191 int use_palette,
192 int palette_size, int transform_bits,
193 EntropyIx* const min_entropy_ix,
194 int* const red_and_blue_always_zero) {
195 // Allocate histogram set with cache_bits = 0.
196 uint32_t* histo;
197
198 if (use_palette && palette_size <= 16) {
199 // In the case of small palettes, we pack 2, 4 or 8 pixels together. In
200 // practice, small palettes are better than any other transform.
201 *min_entropy_ix = kPalette;
202 *red_and_blue_always_zero = 1;
203 return 1;
204 }
205 histo = (uint32_t*)WebPSafeCalloc(kHistoTotal, sizeof(*histo) * 256);
206 if (histo != NULL) {
207 int i, x, y;
208 const uint32_t* prev_row = NULL;
209 const uint32_t* curr_row = argb;
210 uint32_t pix_prev = argb[0]; // Skip the first pixel.
211 for (y = 0; y < height; ++y) {
212 for (x = 0; x < width; ++x) {
213 const uint32_t pix = curr_row[x];
214 const uint32_t pix_diff = VP8LSubPixels(pix, pix_prev);
215 pix_prev = pix;
216 if ((pix_diff == 0) || (prev_row != NULL && pix == prev_row[x])) {
217 continue;
218 }
219 AddSingle(pix,
220 &histo[kHistoAlpha * 256],
221 &histo[kHistoRed * 256],
222 &histo[kHistoGreen * 256],
223 &histo[kHistoBlue * 256]);
224 AddSingle(pix_diff,
225 &histo[kHistoAlphaPred * 256],
226 &histo[kHistoRedPred * 256],
227 &histo[kHistoGreenPred * 256],
228 &histo[kHistoBluePred * 256]);
229 AddSingleSubGreen(pix,
230 &histo[kHistoRedSubGreen * 256],
231 &histo[kHistoBlueSubGreen * 256]);
232 AddSingleSubGreen(pix_diff,
233 &histo[kHistoRedPredSubGreen * 256],
234 &histo[kHistoBluePredSubGreen * 256]);
235 {
236 // Approximate the palette by the entropy of the multiplicative hash.
237 const uint32_t hash = HashPix(pix);
238 ++histo[kHistoPalette * 256 + hash];
239 }
240 }
241 prev_row = curr_row;
242 curr_row += argb_stride;
243 }
244 {
245 double entropy_comp[kHistoTotal];
246 double entropy[kNumEntropyIx];
247 int k;
248 int last_mode_to_analyze = use_palette ? kPalette : kSpatialSubGreen;
249 int j;
250 // Let's add one zero to the predicted histograms. The zeros are removed
251 // too efficiently by the pix_diff == 0 comparison, at least one of the
252 // zeros is likely to exist.
253 ++histo[kHistoRedPredSubGreen * 256];
254 ++histo[kHistoBluePredSubGreen * 256];
255 ++histo[kHistoRedPred * 256];
256 ++histo[kHistoGreenPred * 256];
257 ++histo[kHistoBluePred * 256];
258 ++histo[kHistoAlphaPred * 256];
259
260 for (j = 0; j < kHistoTotal; ++j) {
261 entropy_comp[j] = VP8LBitsEntropy(&histo[j * 256], 256);
262 }
263 entropy[kDirect] = entropy_comp[kHistoAlpha] +
264 entropy_comp[kHistoRed] +
265 entropy_comp[kHistoGreen] +
266 entropy_comp[kHistoBlue];
267 entropy[kSpatial] = entropy_comp[kHistoAlphaPred] +
268 entropy_comp[kHistoRedPred] +
269 entropy_comp[kHistoGreenPred] +
270 entropy_comp[kHistoBluePred];
271 entropy[kSubGreen] = entropy_comp[kHistoAlpha] +
272 entropy_comp[kHistoRedSubGreen] +
273 entropy_comp[kHistoGreen] +
274 entropy_comp[kHistoBlueSubGreen];
275 entropy[kSpatialSubGreen] = entropy_comp[kHistoAlphaPred] +
276 entropy_comp[kHistoRedPredSubGreen] +
277 entropy_comp[kHistoGreenPred] +
278 entropy_comp[kHistoBluePredSubGreen];
279 entropy[kPalette] = entropy_comp[kHistoPalette];
280
281 // When including transforms, there is an overhead in bits from
282 // storing them. This overhead is small but matters for small images.
283 // For spatial, there are 14 transformations.
284 entropy[kSpatial] += VP8LSubSampleSize(width, transform_bits) *
285 VP8LSubSampleSize(height, transform_bits) *
286 VP8LFastLog2(14);
287 // For color transforms: 24 as only 3 channels are considered in a
288 // ColorTransformElement.
289 entropy[kSpatialSubGreen] += VP8LSubSampleSize(width, transform_bits) *
290 VP8LSubSampleSize(height, transform_bits) *
291 VP8LFastLog2(24);
292 // For palettes, add the cost of storing the palette.
293 // We empirically estimate the cost of a compressed entry as 8 bits.
294 // The palette is differential-coded when compressed hence a much
295 // lower cost than sizeof(uint32_t)*8.
296 entropy[kPalette] += palette_size * 8;
297
298 *min_entropy_ix = kDirect;
299 for (k = kDirect + 1; k <= last_mode_to_analyze; ++k) {
300 if (entropy[*min_entropy_ix] > entropy[k]) {
301 *min_entropy_ix = (EntropyIx)k;
302 }
303 }
304 assert((int)*min_entropy_ix <= last_mode_to_analyze);
305 *red_and_blue_always_zero = 1;
306 // Let's check if the histogram of the chosen entropy mode has
307 // non-zero red and blue values. If all are zero, we can later skip
308 // the cross color optimization.
309 {
310 static const uint8_t kHistoPairs[5][2] = {
311 { kHistoRed, kHistoBlue },
312 { kHistoRedPred, kHistoBluePred },
313 { kHistoRedSubGreen, kHistoBlueSubGreen },
314 { kHistoRedPredSubGreen, kHistoBluePredSubGreen },
315 { kHistoRed, kHistoBlue }
316 };
317 const uint32_t* const red_histo =
318 &histo[256 * kHistoPairs[*min_entropy_ix][0]];
319 const uint32_t* const blue_histo =
320 &histo[256 * kHistoPairs[*min_entropy_ix][1]];
321 for (i = 1; i < 256; ++i) {
322 if ((red_histo[i] | blue_histo[i]) != 0) {
323 *red_and_blue_always_zero = 0;
324 break;
325 }
326 }
327 }
328 }
329 WebPSafeFree(histo);
330 return 1;
331 } else {
332 return 0;
333 }
334 }
335
GetHistoBits(int method,int use_palette,int width,int height)336 static int GetHistoBits(int method, int use_palette, int width, int height) {
337 // Make tile size a function of encoding method (Range: 0 to 6).
338 int histo_bits = (use_palette ? 9 : 7) - method;
339 while (1) {
340 const int huff_image_size = VP8LSubSampleSize(width, histo_bits) *
341 VP8LSubSampleSize(height, histo_bits);
342 if (huff_image_size <= MAX_HUFF_IMAGE_SIZE) break;
343 ++histo_bits;
344 }
345 return (histo_bits < MIN_HUFFMAN_BITS) ? MIN_HUFFMAN_BITS :
346 (histo_bits > MAX_HUFFMAN_BITS) ? MAX_HUFFMAN_BITS : histo_bits;
347 }
348
GetTransformBits(int method,int histo_bits)349 static int GetTransformBits(int method, int histo_bits) {
350 const int max_transform_bits = (method < 4) ? 6 : (method > 4) ? 4 : 5;
351 const int res =
352 (histo_bits > max_transform_bits) ? max_transform_bits : histo_bits;
353 assert(res <= MAX_TRANSFORM_BITS);
354 return res;
355 }
356
357 // Set of parameters to be used in each iteration of the cruncher.
358 #define CRUNCH_SUBCONFIGS_MAX 2
359 typedef struct {
360 int lz77_;
361 int do_no_cache_;
362 } CrunchSubConfig;
363 typedef struct {
364 int entropy_idx_;
365 CrunchSubConfig sub_configs_[CRUNCH_SUBCONFIGS_MAX];
366 int sub_configs_size_;
367 } CrunchConfig;
368
369 #define CRUNCH_CONFIGS_MAX kNumEntropyIx
370
EncoderAnalyze(VP8LEncoder * const enc,CrunchConfig crunch_configs[CRUNCH_CONFIGS_MAX],int * const crunch_configs_size,int * const red_and_blue_always_zero)371 static int EncoderAnalyze(VP8LEncoder* const enc,
372 CrunchConfig crunch_configs[CRUNCH_CONFIGS_MAX],
373 int* const crunch_configs_size,
374 int* const red_and_blue_always_zero) {
375 const WebPPicture* const pic = enc->pic_;
376 const int width = pic->width;
377 const int height = pic->height;
378 const WebPConfig* const config = enc->config_;
379 const int method = config->method;
380 const int low_effort = (config->method == 0);
381 int i;
382 int use_palette;
383 int n_lz77s;
384 // If set to 0, analyze the cache with the computed cache value. If 1, also
385 // analyze with no-cache.
386 int do_no_cache = 0;
387 assert(pic != NULL && pic->argb != NULL);
388
389 use_palette =
390 AnalyzeAndCreatePalette(pic, low_effort,
391 enc->palette_, &enc->palette_size_);
392
393 // Empirical bit sizes.
394 enc->histo_bits_ = GetHistoBits(method, use_palette,
395 pic->width, pic->height);
396 enc->transform_bits_ = GetTransformBits(method, enc->histo_bits_);
397
398 if (low_effort) {
399 // AnalyzeEntropy is somewhat slow.
400 crunch_configs[0].entropy_idx_ = use_palette ? kPalette : kSpatialSubGreen;
401 n_lz77s = 1;
402 *crunch_configs_size = 1;
403 } else {
404 EntropyIx min_entropy_ix;
405 // Try out multiple LZ77 on images with few colors.
406 n_lz77s = (enc->palette_size_ > 0 && enc->palette_size_ <= 16) ? 2 : 1;
407 if (!AnalyzeEntropy(pic->argb, width, height, pic->argb_stride, use_palette,
408 enc->palette_size_, enc->transform_bits_,
409 &min_entropy_ix, red_and_blue_always_zero)) {
410 return 0;
411 }
412 if (method == 6 && config->quality == 100) {
413 do_no_cache = 1;
414 // Go brute force on all transforms.
415 *crunch_configs_size = 0;
416 for (i = 0; i < kNumEntropyIx; ++i) {
417 // We can only apply kPalette or kPaletteAndSpatial if we can indeed use
418 // a palette.
419 if ((i != kPalette && i != kPaletteAndSpatial) || use_palette) {
420 assert(*crunch_configs_size < CRUNCH_CONFIGS_MAX);
421 crunch_configs[(*crunch_configs_size)++].entropy_idx_ = i;
422 }
423 }
424 } else {
425 // Only choose the guessed best transform.
426 *crunch_configs_size = 1;
427 crunch_configs[0].entropy_idx_ = min_entropy_ix;
428 if (config->quality >= 75 && method == 5) {
429 // Test with and without color cache.
430 do_no_cache = 1;
431 // If we have a palette, also check in combination with spatial.
432 if (min_entropy_ix == kPalette) {
433 *crunch_configs_size = 2;
434 crunch_configs[1].entropy_idx_ = kPaletteAndSpatial;
435 }
436 }
437 }
438 }
439 // Fill in the different LZ77s.
440 assert(n_lz77s <= CRUNCH_SUBCONFIGS_MAX);
441 for (i = 0; i < *crunch_configs_size; ++i) {
442 int j;
443 for (j = 0; j < n_lz77s; ++j) {
444 assert(j < CRUNCH_SUBCONFIGS_MAX);
445 crunch_configs[i].sub_configs_[j].lz77_ =
446 (j == 0) ? kLZ77Standard | kLZ77RLE : kLZ77Box;
447 crunch_configs[i].sub_configs_[j].do_no_cache_ = do_no_cache;
448 }
449 crunch_configs[i].sub_configs_size_ = n_lz77s;
450 }
451 return 1;
452 }
453
EncoderInit(VP8LEncoder * const enc)454 static int EncoderInit(VP8LEncoder* const enc) {
455 const WebPPicture* const pic = enc->pic_;
456 const int width = pic->width;
457 const int height = pic->height;
458 const int pix_cnt = width * height;
459 // we round the block size up, so we're guaranteed to have
460 // at most MAX_REFS_BLOCK_PER_IMAGE blocks used:
461 const int refs_block_size = (pix_cnt - 1) / MAX_REFS_BLOCK_PER_IMAGE + 1;
462 int i;
463 if (!VP8LHashChainInit(&enc->hash_chain_, pix_cnt)) return 0;
464
465 for (i = 0; i < 4; ++i) VP8LBackwardRefsInit(&enc->refs_[i], refs_block_size);
466
467 return 1;
468 }
469
470 // Returns false in case of memory error.
GetHuffBitLengthsAndCodes(const VP8LHistogramSet * const histogram_image,HuffmanTreeCode * const huffman_codes)471 static int GetHuffBitLengthsAndCodes(
472 const VP8LHistogramSet* const histogram_image,
473 HuffmanTreeCode* const huffman_codes) {
474 int i, k;
475 int ok = 0;
476 uint64_t total_length_size = 0;
477 uint8_t* mem_buf = NULL;
478 const int histogram_image_size = histogram_image->size;
479 int max_num_symbols = 0;
480 uint8_t* buf_rle = NULL;
481 HuffmanTree* huff_tree = NULL;
482
483 // Iterate over all histograms and get the aggregate number of codes used.
484 for (i = 0; i < histogram_image_size; ++i) {
485 const VP8LHistogram* const histo = histogram_image->histograms[i];
486 HuffmanTreeCode* const codes = &huffman_codes[5 * i];
487 assert(histo != NULL);
488 for (k = 0; k < 5; ++k) {
489 const int num_symbols =
490 (k == 0) ? VP8LHistogramNumCodes(histo->palette_code_bits_) :
491 (k == 4) ? NUM_DISTANCE_CODES : 256;
492 codes[k].num_symbols = num_symbols;
493 total_length_size += num_symbols;
494 }
495 }
496
497 // Allocate and Set Huffman codes.
498 {
499 uint16_t* codes;
500 uint8_t* lengths;
501 mem_buf = (uint8_t*)WebPSafeCalloc(total_length_size,
502 sizeof(*lengths) + sizeof(*codes));
503 if (mem_buf == NULL) goto End;
504
505 codes = (uint16_t*)mem_buf;
506 lengths = (uint8_t*)&codes[total_length_size];
507 for (i = 0; i < 5 * histogram_image_size; ++i) {
508 const int bit_length = huffman_codes[i].num_symbols;
509 huffman_codes[i].codes = codes;
510 huffman_codes[i].code_lengths = lengths;
511 codes += bit_length;
512 lengths += bit_length;
513 if (max_num_symbols < bit_length) {
514 max_num_symbols = bit_length;
515 }
516 }
517 }
518
519 buf_rle = (uint8_t*)WebPSafeMalloc(1ULL, max_num_symbols);
520 huff_tree = (HuffmanTree*)WebPSafeMalloc(3ULL * max_num_symbols,
521 sizeof(*huff_tree));
522 if (buf_rle == NULL || huff_tree == NULL) goto End;
523
524 // Create Huffman trees.
525 for (i = 0; i < histogram_image_size; ++i) {
526 HuffmanTreeCode* const codes = &huffman_codes[5 * i];
527 VP8LHistogram* const histo = histogram_image->histograms[i];
528 VP8LCreateHuffmanTree(histo->literal_, 15, buf_rle, huff_tree, codes + 0);
529 VP8LCreateHuffmanTree(histo->red_, 15, buf_rle, huff_tree, codes + 1);
530 VP8LCreateHuffmanTree(histo->blue_, 15, buf_rle, huff_tree, codes + 2);
531 VP8LCreateHuffmanTree(histo->alpha_, 15, buf_rle, huff_tree, codes + 3);
532 VP8LCreateHuffmanTree(histo->distance_, 15, buf_rle, huff_tree, codes + 4);
533 }
534 ok = 1;
535 End:
536 WebPSafeFree(huff_tree);
537 WebPSafeFree(buf_rle);
538 if (!ok) {
539 WebPSafeFree(mem_buf);
540 memset(huffman_codes, 0, 5 * histogram_image_size * sizeof(*huffman_codes));
541 }
542 return ok;
543 }
544
StoreHuffmanTreeOfHuffmanTreeToBitMask(VP8LBitWriter * const bw,const uint8_t * code_length_bitdepth)545 static void StoreHuffmanTreeOfHuffmanTreeToBitMask(
546 VP8LBitWriter* const bw, const uint8_t* code_length_bitdepth) {
547 // RFC 1951 will calm you down if you are worried about this funny sequence.
548 // This sequence is tuned from that, but more weighted for lower symbol count,
549 // and more spiking histograms.
550 static const uint8_t kStorageOrder[CODE_LENGTH_CODES] = {
551 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
552 };
553 int i;
554 // Throw away trailing zeros:
555 int codes_to_store = CODE_LENGTH_CODES;
556 for (; codes_to_store > 4; --codes_to_store) {
557 if (code_length_bitdepth[kStorageOrder[codes_to_store - 1]] != 0) {
558 break;
559 }
560 }
561 VP8LPutBits(bw, codes_to_store - 4, 4);
562 for (i = 0; i < codes_to_store; ++i) {
563 VP8LPutBits(bw, code_length_bitdepth[kStorageOrder[i]], 3);
564 }
565 }
566
ClearHuffmanTreeIfOnlyOneSymbol(HuffmanTreeCode * const huffman_code)567 static void ClearHuffmanTreeIfOnlyOneSymbol(
568 HuffmanTreeCode* const huffman_code) {
569 int k;
570 int count = 0;
571 for (k = 0; k < huffman_code->num_symbols; ++k) {
572 if (huffman_code->code_lengths[k] != 0) {
573 ++count;
574 if (count > 1) return;
575 }
576 }
577 for (k = 0; k < huffman_code->num_symbols; ++k) {
578 huffman_code->code_lengths[k] = 0;
579 huffman_code->codes[k] = 0;
580 }
581 }
582
StoreHuffmanTreeToBitMask(VP8LBitWriter * const bw,const HuffmanTreeToken * const tokens,const int num_tokens,const HuffmanTreeCode * const huffman_code)583 static void StoreHuffmanTreeToBitMask(
584 VP8LBitWriter* const bw,
585 const HuffmanTreeToken* const tokens, const int num_tokens,
586 const HuffmanTreeCode* const huffman_code) {
587 int i;
588 for (i = 0; i < num_tokens; ++i) {
589 const int ix = tokens[i].code;
590 const int extra_bits = tokens[i].extra_bits;
591 VP8LPutBits(bw, huffman_code->codes[ix], huffman_code->code_lengths[ix]);
592 switch (ix) {
593 case 16:
594 VP8LPutBits(bw, extra_bits, 2);
595 break;
596 case 17:
597 VP8LPutBits(bw, extra_bits, 3);
598 break;
599 case 18:
600 VP8LPutBits(bw, extra_bits, 7);
601 break;
602 }
603 }
604 }
605
606 // 'huff_tree' and 'tokens' are pre-alloacted buffers.
StoreFullHuffmanCode(VP8LBitWriter * const bw,HuffmanTree * const huff_tree,HuffmanTreeToken * const tokens,const HuffmanTreeCode * const tree)607 static void StoreFullHuffmanCode(VP8LBitWriter* const bw,
608 HuffmanTree* const huff_tree,
609 HuffmanTreeToken* const tokens,
610 const HuffmanTreeCode* const tree) {
611 uint8_t code_length_bitdepth[CODE_LENGTH_CODES] = { 0 };
612 uint16_t code_length_bitdepth_symbols[CODE_LENGTH_CODES] = { 0 };
613 const int max_tokens = tree->num_symbols;
614 int num_tokens;
615 HuffmanTreeCode huffman_code;
616 huffman_code.num_symbols = CODE_LENGTH_CODES;
617 huffman_code.code_lengths = code_length_bitdepth;
618 huffman_code.codes = code_length_bitdepth_symbols;
619
620 VP8LPutBits(bw, 0, 1);
621 num_tokens = VP8LCreateCompressedHuffmanTree(tree, tokens, max_tokens);
622 {
623 uint32_t histogram[CODE_LENGTH_CODES] = { 0 };
624 uint8_t buf_rle[CODE_LENGTH_CODES] = { 0 };
625 int i;
626 for (i = 0; i < num_tokens; ++i) {
627 ++histogram[tokens[i].code];
628 }
629
630 VP8LCreateHuffmanTree(histogram, 7, buf_rle, huff_tree, &huffman_code);
631 }
632
633 StoreHuffmanTreeOfHuffmanTreeToBitMask(bw, code_length_bitdepth);
634 ClearHuffmanTreeIfOnlyOneSymbol(&huffman_code);
635 {
636 int trailing_zero_bits = 0;
637 int trimmed_length = num_tokens;
638 int write_trimmed_length;
639 int length;
640 int i = num_tokens;
641 while (i-- > 0) {
642 const int ix = tokens[i].code;
643 if (ix == 0 || ix == 17 || ix == 18) {
644 --trimmed_length; // discount trailing zeros
645 trailing_zero_bits += code_length_bitdepth[ix];
646 if (ix == 17) {
647 trailing_zero_bits += 3;
648 } else if (ix == 18) {
649 trailing_zero_bits += 7;
650 }
651 } else {
652 break;
653 }
654 }
655 write_trimmed_length = (trimmed_length > 1 && trailing_zero_bits > 12);
656 length = write_trimmed_length ? trimmed_length : num_tokens;
657 VP8LPutBits(bw, write_trimmed_length, 1);
658 if (write_trimmed_length) {
659 if (trimmed_length == 2) {
660 VP8LPutBits(bw, 0, 3 + 2); // nbitpairs=1, trimmed_length=2
661 } else {
662 const int nbits = BitsLog2Floor(trimmed_length - 2);
663 const int nbitpairs = nbits / 2 + 1;
664 assert(trimmed_length > 2);
665 assert(nbitpairs - 1 < 8);
666 VP8LPutBits(bw, nbitpairs - 1, 3);
667 VP8LPutBits(bw, trimmed_length - 2, nbitpairs * 2);
668 }
669 }
670 StoreHuffmanTreeToBitMask(bw, tokens, length, &huffman_code);
671 }
672 }
673
674 // 'huff_tree' and 'tokens' are pre-alloacted buffers.
StoreHuffmanCode(VP8LBitWriter * const bw,HuffmanTree * const huff_tree,HuffmanTreeToken * const tokens,const HuffmanTreeCode * const huffman_code)675 static void StoreHuffmanCode(VP8LBitWriter* const bw,
676 HuffmanTree* const huff_tree,
677 HuffmanTreeToken* const tokens,
678 const HuffmanTreeCode* const huffman_code) {
679 int i;
680 int count = 0;
681 int symbols[2] = { 0, 0 };
682 const int kMaxBits = 8;
683 const int kMaxSymbol = 1 << kMaxBits;
684
685 // Check whether it's a small tree.
686 for (i = 0; i < huffman_code->num_symbols && count < 3; ++i) {
687 if (huffman_code->code_lengths[i] != 0) {
688 if (count < 2) symbols[count] = i;
689 ++count;
690 }
691 }
692
693 if (count == 0) { // emit minimal tree for empty cases
694 // bits: small tree marker: 1, count-1: 0, large 8-bit code: 0, code: 0
695 VP8LPutBits(bw, 0x01, 4);
696 } else if (count <= 2 && symbols[0] < kMaxSymbol && symbols[1] < kMaxSymbol) {
697 VP8LPutBits(bw, 1, 1); // Small tree marker to encode 1 or 2 symbols.
698 VP8LPutBits(bw, count - 1, 1);
699 if (symbols[0] <= 1) {
700 VP8LPutBits(bw, 0, 1); // Code bit for small (1 bit) symbol value.
701 VP8LPutBits(bw, symbols[0], 1);
702 } else {
703 VP8LPutBits(bw, 1, 1);
704 VP8LPutBits(bw, symbols[0], 8);
705 }
706 if (count == 2) {
707 VP8LPutBits(bw, symbols[1], 8);
708 }
709 } else {
710 StoreFullHuffmanCode(bw, huff_tree, tokens, huffman_code);
711 }
712 }
713
WriteHuffmanCode(VP8LBitWriter * const bw,const HuffmanTreeCode * const code,int code_index)714 static WEBP_INLINE void WriteHuffmanCode(VP8LBitWriter* const bw,
715 const HuffmanTreeCode* const code,
716 int code_index) {
717 const int depth = code->code_lengths[code_index];
718 const int symbol = code->codes[code_index];
719 VP8LPutBits(bw, symbol, depth);
720 }
721
WriteHuffmanCodeWithExtraBits(VP8LBitWriter * const bw,const HuffmanTreeCode * const code,int code_index,int bits,int n_bits)722 static WEBP_INLINE void WriteHuffmanCodeWithExtraBits(
723 VP8LBitWriter* const bw,
724 const HuffmanTreeCode* const code,
725 int code_index,
726 int bits,
727 int n_bits) {
728 const int depth = code->code_lengths[code_index];
729 const int symbol = code->codes[code_index];
730 VP8LPutBits(bw, (bits << depth) | symbol, depth + n_bits);
731 }
732
StoreImageToBitMask(VP8LBitWriter * const bw,int width,int histo_bits,const VP8LBackwardRefs * const refs,const uint16_t * histogram_symbols,const HuffmanTreeCode * const huffman_codes)733 static WebPEncodingError StoreImageToBitMask(
734 VP8LBitWriter* const bw, int width, int histo_bits,
735 const VP8LBackwardRefs* const refs,
736 const uint16_t* histogram_symbols,
737 const HuffmanTreeCode* const huffman_codes) {
738 const int histo_xsize = histo_bits ? VP8LSubSampleSize(width, histo_bits) : 1;
739 const int tile_mask = (histo_bits == 0) ? 0 : -(1 << histo_bits);
740 // x and y trace the position in the image.
741 int x = 0;
742 int y = 0;
743 int tile_x = x & tile_mask;
744 int tile_y = y & tile_mask;
745 int histogram_ix = histogram_symbols[0];
746 const HuffmanTreeCode* codes = huffman_codes + 5 * histogram_ix;
747 VP8LRefsCursor c = VP8LRefsCursorInit(refs);
748 while (VP8LRefsCursorOk(&c)) {
749 const PixOrCopy* const v = c.cur_pos;
750 if ((tile_x != (x & tile_mask)) || (tile_y != (y & tile_mask))) {
751 tile_x = x & tile_mask;
752 tile_y = y & tile_mask;
753 histogram_ix = histogram_symbols[(y >> histo_bits) * histo_xsize +
754 (x >> histo_bits)];
755 codes = huffman_codes + 5 * histogram_ix;
756 }
757 if (PixOrCopyIsLiteral(v)) {
758 static const uint8_t order[] = { 1, 2, 0, 3 };
759 int k;
760 for (k = 0; k < 4; ++k) {
761 const int code = PixOrCopyLiteral(v, order[k]);
762 WriteHuffmanCode(bw, codes + k, code);
763 }
764 } else if (PixOrCopyIsCacheIdx(v)) {
765 const int code = PixOrCopyCacheIdx(v);
766 const int literal_ix = 256 + NUM_LENGTH_CODES + code;
767 WriteHuffmanCode(bw, codes, literal_ix);
768 } else {
769 int bits, n_bits;
770 int code;
771
772 const int distance = PixOrCopyDistance(v);
773 VP8LPrefixEncode(v->len, &code, &n_bits, &bits);
774 WriteHuffmanCodeWithExtraBits(bw, codes, 256 + code, bits, n_bits);
775
776 // Don't write the distance with the extra bits code since
777 // the distance can be up to 18 bits of extra bits, and the prefix
778 // 15 bits, totaling to 33, and our PutBits only supports up to 32 bits.
779 VP8LPrefixEncode(distance, &code, &n_bits, &bits);
780 WriteHuffmanCode(bw, codes + 4, code);
781 VP8LPutBits(bw, bits, n_bits);
782 }
783 x += PixOrCopyLength(v);
784 while (x >= width) {
785 x -= width;
786 ++y;
787 }
788 VP8LRefsCursorNext(&c);
789 }
790 return bw->error_ ? VP8_ENC_ERROR_OUT_OF_MEMORY : VP8_ENC_OK;
791 }
792
793 // Special case of EncodeImageInternal() for cache-bits=0, histo_bits=31
EncodeImageNoHuffman(VP8LBitWriter * const bw,const uint32_t * const argb,VP8LHashChain * const hash_chain,VP8LBackwardRefs * const refs_array,int width,int height,int quality,int low_effort)794 static WebPEncodingError EncodeImageNoHuffman(
795 VP8LBitWriter* const bw, const uint32_t* const argb,
796 VP8LHashChain* const hash_chain, VP8LBackwardRefs* const refs_array,
797 int width, int height, int quality, int low_effort) {
798 int i;
799 int max_tokens = 0;
800 WebPEncodingError err = VP8_ENC_OK;
801 VP8LBackwardRefs* refs;
802 HuffmanTreeToken* tokens = NULL;
803 HuffmanTreeCode huffman_codes[5] = { { 0, NULL, NULL } };
804 const uint16_t histogram_symbols[1] = { 0 }; // only one tree, one symbol
805 int cache_bits = 0;
806 VP8LHistogramSet* histogram_image = NULL;
807 HuffmanTree* const huff_tree = (HuffmanTree*)WebPSafeMalloc(
808 3ULL * CODE_LENGTH_CODES, sizeof(*huff_tree));
809 if (huff_tree == NULL) {
810 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
811 goto Error;
812 }
813
814 // Calculate backward references from ARGB image.
815 if (!VP8LHashChainFill(hash_chain, quality, argb, width, height,
816 low_effort)) {
817 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
818 goto Error;
819 }
820 err = VP8LGetBackwardReferences(
821 width, height, argb, quality, /*low_effort=*/0, kLZ77Standard | kLZ77RLE,
822 cache_bits, /*do_no_cache=*/0, hash_chain, refs_array, &cache_bits);
823 if (err != VP8_ENC_OK) goto Error;
824 refs = &refs_array[0];
825 histogram_image = VP8LAllocateHistogramSet(1, cache_bits);
826 if (histogram_image == NULL) {
827 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
828 goto Error;
829 }
830 VP8LHistogramSetClear(histogram_image);
831
832 // Build histogram image and symbols from backward references.
833 VP8LHistogramStoreRefs(refs, histogram_image->histograms[0]);
834
835 // Create Huffman bit lengths and codes for each histogram image.
836 assert(histogram_image->size == 1);
837 if (!GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) {
838 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
839 goto Error;
840 }
841
842 // No color cache, no Huffman image.
843 VP8LPutBits(bw, 0, 1);
844
845 // Find maximum number of symbols for the huffman tree-set.
846 for (i = 0; i < 5; ++i) {
847 HuffmanTreeCode* const codes = &huffman_codes[i];
848 if (max_tokens < codes->num_symbols) {
849 max_tokens = codes->num_symbols;
850 }
851 }
852
853 tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, sizeof(*tokens));
854 if (tokens == NULL) {
855 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
856 goto Error;
857 }
858
859 // Store Huffman codes.
860 for (i = 0; i < 5; ++i) {
861 HuffmanTreeCode* const codes = &huffman_codes[i];
862 StoreHuffmanCode(bw, huff_tree, tokens, codes);
863 ClearHuffmanTreeIfOnlyOneSymbol(codes);
864 }
865
866 // Store actual literals.
867 err = StoreImageToBitMask(bw, width, 0, refs, histogram_symbols,
868 huffman_codes);
869
870 Error:
871 WebPSafeFree(tokens);
872 WebPSafeFree(huff_tree);
873 VP8LFreeHistogramSet(histogram_image);
874 WebPSafeFree(huffman_codes[0].codes);
875 return err;
876 }
877
EncodeImageInternal(VP8LBitWriter * const bw,const uint32_t * const argb,VP8LHashChain * const hash_chain,VP8LBackwardRefs refs_array[4],int width,int height,int quality,int low_effort,int use_cache,const CrunchConfig * const config,int * cache_bits,int histogram_bits,size_t init_byte_position,int * const hdr_size,int * const data_size)878 static WebPEncodingError EncodeImageInternal(
879 VP8LBitWriter* const bw, const uint32_t* const argb,
880 VP8LHashChain* const hash_chain, VP8LBackwardRefs refs_array[4], int width,
881 int height, int quality, int low_effort, int use_cache,
882 const CrunchConfig* const config, int* cache_bits, int histogram_bits,
883 size_t init_byte_position, int* const hdr_size, int* const data_size) {
884 WebPEncodingError err = VP8_ENC_ERROR_OUT_OF_MEMORY;
885 const uint32_t histogram_image_xysize =
886 VP8LSubSampleSize(width, histogram_bits) *
887 VP8LSubSampleSize(height, histogram_bits);
888 VP8LHistogramSet* histogram_image = NULL;
889 VP8LHistogram* tmp_histo = NULL;
890 int histogram_image_size = 0;
891 size_t bit_array_size = 0;
892 HuffmanTree* const huff_tree = (HuffmanTree*)WebPSafeMalloc(
893 3ULL * CODE_LENGTH_CODES, sizeof(*huff_tree));
894 HuffmanTreeToken* tokens = NULL;
895 HuffmanTreeCode* huffman_codes = NULL;
896 uint16_t* const histogram_symbols =
897 (uint16_t*)WebPSafeMalloc(histogram_image_xysize,
898 sizeof(*histogram_symbols));
899 int sub_configs_idx;
900 int cache_bits_init, write_histogram_image;
901 VP8LBitWriter bw_init = *bw, bw_best;
902 int hdr_size_tmp;
903 VP8LHashChain hash_chain_histogram; // histogram image hash chain
904 size_t bw_size_best = ~(size_t)0;
905 assert(histogram_bits >= MIN_HUFFMAN_BITS);
906 assert(histogram_bits <= MAX_HUFFMAN_BITS);
907 assert(hdr_size != NULL);
908 assert(data_size != NULL);
909
910 // Make sure we can allocate the different objects.
911 memset(&hash_chain_histogram, 0, sizeof(hash_chain_histogram));
912 if (huff_tree == NULL || histogram_symbols == NULL ||
913 !VP8LHashChainInit(&hash_chain_histogram, histogram_image_xysize) ||
914 !VP8LHashChainFill(hash_chain, quality, argb, width, height,
915 low_effort)) {
916 goto Error;
917 }
918 if (use_cache) {
919 // If the value is different from zero, it has been set during the
920 // palette analysis.
921 cache_bits_init = (*cache_bits == 0) ? MAX_COLOR_CACHE_BITS : *cache_bits;
922 } else {
923 cache_bits_init = 0;
924 }
925 // If several iterations will happen, clone into bw_best.
926 if (!VP8LBitWriterInit(&bw_best, 0) ||
927 ((config->sub_configs_size_ > 1 ||
928 config->sub_configs_[0].do_no_cache_) &&
929 !VP8LBitWriterClone(bw, &bw_best))) {
930 goto Error;
931 }
932 for (sub_configs_idx = 0; sub_configs_idx < config->sub_configs_size_;
933 ++sub_configs_idx) {
934 const CrunchSubConfig* const sub_config =
935 &config->sub_configs_[sub_configs_idx];
936 int cache_bits_best, i_cache;
937 err = VP8LGetBackwardReferences(width, height, argb, quality, low_effort,
938 sub_config->lz77_, cache_bits_init,
939 sub_config->do_no_cache_, hash_chain,
940 &refs_array[0], &cache_bits_best);
941 if (err != VP8_ENC_OK) goto Error;
942
943 for (i_cache = 0; i_cache < (sub_config->do_no_cache_ ? 2 : 1); ++i_cache) {
944 const int cache_bits_tmp = (i_cache == 0) ? cache_bits_best : 0;
945 // Speed-up: no need to study the no-cache case if it was already studied
946 // in i_cache == 0.
947 if (i_cache == 1 && cache_bits_best == 0) break;
948
949 // Reset the bit writer for this iteration.
950 VP8LBitWriterReset(&bw_init, bw);
951
952 // Build histogram image and symbols from backward references.
953 histogram_image =
954 VP8LAllocateHistogramSet(histogram_image_xysize, cache_bits_tmp);
955 tmp_histo = VP8LAllocateHistogram(cache_bits_tmp);
956 if (histogram_image == NULL || tmp_histo == NULL ||
957 !VP8LGetHistoImageSymbols(width, height, &refs_array[i_cache],
958 quality, low_effort, histogram_bits,
959 cache_bits_tmp, histogram_image, tmp_histo,
960 histogram_symbols)) {
961 goto Error;
962 }
963 // Create Huffman bit lengths and codes for each histogram image.
964 histogram_image_size = histogram_image->size;
965 bit_array_size = 5 * histogram_image_size;
966 huffman_codes = (HuffmanTreeCode*)WebPSafeCalloc(bit_array_size,
967 sizeof(*huffman_codes));
968 // Note: some histogram_image entries may point to tmp_histos[], so the
969 // latter need to outlive the following call to
970 // GetHuffBitLengthsAndCodes().
971 if (huffman_codes == NULL ||
972 !GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) {
973 goto Error;
974 }
975 // Free combined histograms.
976 VP8LFreeHistogramSet(histogram_image);
977 histogram_image = NULL;
978
979 // Free scratch histograms.
980 VP8LFreeHistogram(tmp_histo);
981 tmp_histo = NULL;
982
983 // Color Cache parameters.
984 if (cache_bits_tmp > 0) {
985 VP8LPutBits(bw, 1, 1);
986 VP8LPutBits(bw, cache_bits_tmp, 4);
987 } else {
988 VP8LPutBits(bw, 0, 1);
989 }
990
991 // Huffman image + meta huffman.
992 write_histogram_image = (histogram_image_size > 1);
993 VP8LPutBits(bw, write_histogram_image, 1);
994 if (write_histogram_image) {
995 uint32_t* const histogram_argb =
996 (uint32_t*)WebPSafeMalloc(histogram_image_xysize,
997 sizeof(*histogram_argb));
998 int max_index = 0;
999 uint32_t i;
1000 if (histogram_argb == NULL) goto Error;
1001 for (i = 0; i < histogram_image_xysize; ++i) {
1002 const int symbol_index = histogram_symbols[i] & 0xffff;
1003 histogram_argb[i] = (symbol_index << 8);
1004 if (symbol_index >= max_index) {
1005 max_index = symbol_index + 1;
1006 }
1007 }
1008 histogram_image_size = max_index;
1009
1010 VP8LPutBits(bw, histogram_bits - 2, 3);
1011 err = EncodeImageNoHuffman(
1012 bw, histogram_argb, &hash_chain_histogram, &refs_array[2],
1013 VP8LSubSampleSize(width, histogram_bits),
1014 VP8LSubSampleSize(height, histogram_bits), quality, low_effort);
1015 WebPSafeFree(histogram_argb);
1016 if (err != VP8_ENC_OK) goto Error;
1017 }
1018
1019 // Store Huffman codes.
1020 {
1021 int i;
1022 int max_tokens = 0;
1023 // Find maximum number of symbols for the huffman tree-set.
1024 for (i = 0; i < 5 * histogram_image_size; ++i) {
1025 HuffmanTreeCode* const codes = &huffman_codes[i];
1026 if (max_tokens < codes->num_symbols) {
1027 max_tokens = codes->num_symbols;
1028 }
1029 }
1030 tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, sizeof(*tokens));
1031 if (tokens == NULL) goto Error;
1032 for (i = 0; i < 5 * histogram_image_size; ++i) {
1033 HuffmanTreeCode* const codes = &huffman_codes[i];
1034 StoreHuffmanCode(bw, huff_tree, tokens, codes);
1035 ClearHuffmanTreeIfOnlyOneSymbol(codes);
1036 }
1037 }
1038 // Store actual literals.
1039 hdr_size_tmp = (int)(VP8LBitWriterNumBytes(bw) - init_byte_position);
1040 err = StoreImageToBitMask(bw, width, histogram_bits, &refs_array[i_cache],
1041 histogram_symbols, huffman_codes);
1042 if (err != VP8_ENC_OK) goto Error;
1043 // Keep track of the smallest image so far.
1044 if (VP8LBitWriterNumBytes(bw) < bw_size_best) {
1045 bw_size_best = VP8LBitWriterNumBytes(bw);
1046 *cache_bits = cache_bits_tmp;
1047 *hdr_size = hdr_size_tmp;
1048 *data_size =
1049 (int)(VP8LBitWriterNumBytes(bw) - init_byte_position - *hdr_size);
1050 VP8LBitWriterSwap(bw, &bw_best);
1051 }
1052 WebPSafeFree(tokens);
1053 tokens = NULL;
1054 if (huffman_codes != NULL) {
1055 WebPSafeFree(huffman_codes->codes);
1056 WebPSafeFree(huffman_codes);
1057 huffman_codes = NULL;
1058 }
1059 }
1060 }
1061 VP8LBitWriterSwap(bw, &bw_best);
1062 err = VP8_ENC_OK;
1063
1064 Error:
1065 WebPSafeFree(tokens);
1066 WebPSafeFree(huff_tree);
1067 VP8LFreeHistogramSet(histogram_image);
1068 VP8LFreeHistogram(tmp_histo);
1069 VP8LHashChainClear(&hash_chain_histogram);
1070 if (huffman_codes != NULL) {
1071 WebPSafeFree(huffman_codes->codes);
1072 WebPSafeFree(huffman_codes);
1073 }
1074 WebPSafeFree(histogram_symbols);
1075 VP8LBitWriterWipeOut(&bw_best);
1076 return err;
1077 }
1078
1079 // -----------------------------------------------------------------------------
1080 // Transforms
1081
ApplySubtractGreen(VP8LEncoder * const enc,int width,int height,VP8LBitWriter * const bw)1082 static void ApplySubtractGreen(VP8LEncoder* const enc, int width, int height,
1083 VP8LBitWriter* const bw) {
1084 VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
1085 VP8LPutBits(bw, SUBTRACT_GREEN, 2);
1086 VP8LSubtractGreenFromBlueAndRed(enc->argb_, width * height);
1087 }
1088
ApplyPredictFilter(const VP8LEncoder * const enc,int width,int height,int quality,int low_effort,int used_subtract_green,VP8LBitWriter * const bw)1089 static WebPEncodingError ApplyPredictFilter(const VP8LEncoder* const enc,
1090 int width, int height,
1091 int quality, int low_effort,
1092 int used_subtract_green,
1093 VP8LBitWriter* const bw) {
1094 const int pred_bits = enc->transform_bits_;
1095 const int transform_width = VP8LSubSampleSize(width, pred_bits);
1096 const int transform_height = VP8LSubSampleSize(height, pred_bits);
1097 // we disable near-lossless quantization if palette is used.
1098 const int near_lossless_strength = enc->use_palette_ ? 100
1099 : enc->config_->near_lossless;
1100
1101 VP8LResidualImage(width, height, pred_bits, low_effort, enc->argb_,
1102 enc->argb_scratch_, enc->transform_data_,
1103 near_lossless_strength, enc->config_->exact,
1104 used_subtract_green);
1105 VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
1106 VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2);
1107 assert(pred_bits >= 2);
1108 VP8LPutBits(bw, pred_bits - 2, 3);
1109 return EncodeImageNoHuffman(
1110 bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
1111 (VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,
1112 quality, low_effort);
1113 }
1114
ApplyCrossColorFilter(const VP8LEncoder * const enc,int width,int height,int quality,int low_effort,VP8LBitWriter * const bw)1115 static WebPEncodingError ApplyCrossColorFilter(const VP8LEncoder* const enc,
1116 int width, int height,
1117 int quality, int low_effort,
1118 VP8LBitWriter* const bw) {
1119 const int ccolor_transform_bits = enc->transform_bits_;
1120 const int transform_width = VP8LSubSampleSize(width, ccolor_transform_bits);
1121 const int transform_height = VP8LSubSampleSize(height, ccolor_transform_bits);
1122
1123 VP8LColorSpaceTransform(width, height, ccolor_transform_bits, quality,
1124 enc->argb_, enc->transform_data_);
1125 VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
1126 VP8LPutBits(bw, CROSS_COLOR_TRANSFORM, 2);
1127 assert(ccolor_transform_bits >= 2);
1128 VP8LPutBits(bw, ccolor_transform_bits - 2, 3);
1129 return EncodeImageNoHuffman(
1130 bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
1131 (VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,
1132 quality, low_effort);
1133 }
1134
1135 // -----------------------------------------------------------------------------
1136
WriteRiffHeader(const WebPPicture * const pic,size_t riff_size,size_t vp8l_size)1137 static WebPEncodingError WriteRiffHeader(const WebPPicture* const pic,
1138 size_t riff_size, size_t vp8l_size) {
1139 uint8_t riff[RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE + VP8L_SIGNATURE_SIZE] = {
1140 'R', 'I', 'F', 'F', 0, 0, 0, 0, 'W', 'E', 'B', 'P',
1141 'V', 'P', '8', 'L', 0, 0, 0, 0, VP8L_MAGIC_BYTE,
1142 };
1143 PutLE32(riff + TAG_SIZE, (uint32_t)riff_size);
1144 PutLE32(riff + RIFF_HEADER_SIZE + TAG_SIZE, (uint32_t)vp8l_size);
1145 if (!pic->writer(riff, sizeof(riff), pic)) {
1146 return VP8_ENC_ERROR_BAD_WRITE;
1147 }
1148 return VP8_ENC_OK;
1149 }
1150
WriteImageSize(const WebPPicture * const pic,VP8LBitWriter * const bw)1151 static int WriteImageSize(const WebPPicture* const pic,
1152 VP8LBitWriter* const bw) {
1153 const int width = pic->width - 1;
1154 const int height = pic->height - 1;
1155 assert(width < WEBP_MAX_DIMENSION && height < WEBP_MAX_DIMENSION);
1156
1157 VP8LPutBits(bw, width, VP8L_IMAGE_SIZE_BITS);
1158 VP8LPutBits(bw, height, VP8L_IMAGE_SIZE_BITS);
1159 return !bw->error_;
1160 }
1161
WriteRealAlphaAndVersion(VP8LBitWriter * const bw,int has_alpha)1162 static int WriteRealAlphaAndVersion(VP8LBitWriter* const bw, int has_alpha) {
1163 VP8LPutBits(bw, has_alpha, 1);
1164 VP8LPutBits(bw, VP8L_VERSION, VP8L_VERSION_BITS);
1165 return !bw->error_;
1166 }
1167
WriteImage(const WebPPicture * const pic,VP8LBitWriter * const bw,size_t * const coded_size)1168 static WebPEncodingError WriteImage(const WebPPicture* const pic,
1169 VP8LBitWriter* const bw,
1170 size_t* const coded_size) {
1171 WebPEncodingError err = VP8_ENC_OK;
1172 const uint8_t* const webpll_data = VP8LBitWriterFinish(bw);
1173 const size_t webpll_size = VP8LBitWriterNumBytes(bw);
1174 const size_t vp8l_size = VP8L_SIGNATURE_SIZE + webpll_size;
1175 const size_t pad = vp8l_size & 1;
1176 const size_t riff_size = TAG_SIZE + CHUNK_HEADER_SIZE + vp8l_size + pad;
1177
1178 err = WriteRiffHeader(pic, riff_size, vp8l_size);
1179 if (err != VP8_ENC_OK) goto Error;
1180
1181 if (!pic->writer(webpll_data, webpll_size, pic)) {
1182 err = VP8_ENC_ERROR_BAD_WRITE;
1183 goto Error;
1184 }
1185
1186 if (pad) {
1187 const uint8_t pad_byte[1] = { 0 };
1188 if (!pic->writer(pad_byte, 1, pic)) {
1189 err = VP8_ENC_ERROR_BAD_WRITE;
1190 goto Error;
1191 }
1192 }
1193 *coded_size = CHUNK_HEADER_SIZE + riff_size;
1194 return VP8_ENC_OK;
1195
1196 Error:
1197 return err;
1198 }
1199
1200 // -----------------------------------------------------------------------------
1201
ClearTransformBuffer(VP8LEncoder * const enc)1202 static void ClearTransformBuffer(VP8LEncoder* const enc) {
1203 WebPSafeFree(enc->transform_mem_);
1204 enc->transform_mem_ = NULL;
1205 enc->transform_mem_size_ = 0;
1206 }
1207
1208 // Allocates the memory for argb (W x H) buffer, 2 rows of context for
1209 // prediction and transform data.
1210 // Flags influencing the memory allocated:
1211 // enc->transform_bits_
1212 // enc->use_predict_, enc->use_cross_color_
AllocateTransformBuffer(VP8LEncoder * const enc,int width,int height)1213 static WebPEncodingError AllocateTransformBuffer(VP8LEncoder* const enc,
1214 int width, int height) {
1215 WebPEncodingError err = VP8_ENC_OK;
1216 const uint64_t image_size = width * height;
1217 // VP8LResidualImage needs room for 2 scanlines of uint32 pixels with an extra
1218 // pixel in each, plus 2 regular scanlines of bytes.
1219 // TODO(skal): Clean up by using arithmetic in bytes instead of words.
1220 const uint64_t argb_scratch_size =
1221 enc->use_predict_
1222 ? (width + 1) * 2 +
1223 (width * 2 + sizeof(uint32_t) - 1) / sizeof(uint32_t)
1224 : 0;
1225 const uint64_t transform_data_size =
1226 (enc->use_predict_ || enc->use_cross_color_)
1227 ? VP8LSubSampleSize(width, enc->transform_bits_) *
1228 VP8LSubSampleSize(height, enc->transform_bits_)
1229 : 0;
1230 const uint64_t max_alignment_in_words =
1231 (WEBP_ALIGN_CST + sizeof(uint32_t) - 1) / sizeof(uint32_t);
1232 const uint64_t mem_size =
1233 image_size + max_alignment_in_words +
1234 argb_scratch_size + max_alignment_in_words +
1235 transform_data_size;
1236 uint32_t* mem = enc->transform_mem_;
1237 if (mem == NULL || mem_size > enc->transform_mem_size_) {
1238 ClearTransformBuffer(enc);
1239 mem = (uint32_t*)WebPSafeMalloc(mem_size, sizeof(*mem));
1240 if (mem == NULL) {
1241 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1242 goto Error;
1243 }
1244 enc->transform_mem_ = mem;
1245 enc->transform_mem_size_ = (size_t)mem_size;
1246 enc->argb_content_ = kEncoderNone;
1247 }
1248 enc->argb_ = mem;
1249 mem = (uint32_t*)WEBP_ALIGN(mem + image_size);
1250 enc->argb_scratch_ = mem;
1251 mem = (uint32_t*)WEBP_ALIGN(mem + argb_scratch_size);
1252 enc->transform_data_ = mem;
1253
1254 enc->current_width_ = width;
1255 Error:
1256 return err;
1257 }
1258
MakeInputImageCopy(VP8LEncoder * const enc)1259 static WebPEncodingError MakeInputImageCopy(VP8LEncoder* const enc) {
1260 WebPEncodingError err = VP8_ENC_OK;
1261 const WebPPicture* const picture = enc->pic_;
1262 const int width = picture->width;
1263 const int height = picture->height;
1264
1265 err = AllocateTransformBuffer(enc, width, height);
1266 if (err != VP8_ENC_OK) return err;
1267 if (enc->argb_content_ == kEncoderARGB) return VP8_ENC_OK;
1268
1269 {
1270 uint32_t* dst = enc->argb_;
1271 const uint32_t* src = picture->argb;
1272 int y;
1273 for (y = 0; y < height; ++y) {
1274 memcpy(dst, src, width * sizeof(*dst));
1275 dst += width;
1276 src += picture->argb_stride;
1277 }
1278 }
1279 enc->argb_content_ = kEncoderARGB;
1280 assert(enc->current_width_ == width);
1281 return VP8_ENC_OK;
1282 }
1283
1284 // -----------------------------------------------------------------------------
1285
SearchColorNoIdx(const uint32_t sorted[],uint32_t color,int hi)1286 static WEBP_INLINE int SearchColorNoIdx(const uint32_t sorted[], uint32_t color,
1287 int hi) {
1288 int low = 0;
1289 if (sorted[low] == color) return low; // loop invariant: sorted[low] != color
1290 while (1) {
1291 const int mid = (low + hi) >> 1;
1292 if (sorted[mid] == color) {
1293 return mid;
1294 } else if (sorted[mid] < color) {
1295 low = mid;
1296 } else {
1297 hi = mid;
1298 }
1299 }
1300 }
1301
1302 #define APPLY_PALETTE_GREEDY_MAX 4
1303
SearchColorGreedy(const uint32_t palette[],int palette_size,uint32_t color)1304 static WEBP_INLINE uint32_t SearchColorGreedy(const uint32_t palette[],
1305 int palette_size,
1306 uint32_t color) {
1307 (void)palette_size;
1308 assert(palette_size < APPLY_PALETTE_GREEDY_MAX);
1309 assert(3 == APPLY_PALETTE_GREEDY_MAX - 1);
1310 if (color == palette[0]) return 0;
1311 if (color == palette[1]) return 1;
1312 if (color == palette[2]) return 2;
1313 return 3;
1314 }
1315
ApplyPaletteHash0(uint32_t color)1316 static WEBP_INLINE uint32_t ApplyPaletteHash0(uint32_t color) {
1317 // Focus on the green color.
1318 return (color >> 8) & 0xff;
1319 }
1320
1321 #define PALETTE_INV_SIZE_BITS 11
1322 #define PALETTE_INV_SIZE (1 << PALETTE_INV_SIZE_BITS)
1323
ApplyPaletteHash1(uint32_t color)1324 static WEBP_INLINE uint32_t ApplyPaletteHash1(uint32_t color) {
1325 // Forget about alpha.
1326 return ((uint32_t)((color & 0x00ffffffu) * 4222244071ull)) >>
1327 (32 - PALETTE_INV_SIZE_BITS);
1328 }
1329
ApplyPaletteHash2(uint32_t color)1330 static WEBP_INLINE uint32_t ApplyPaletteHash2(uint32_t color) {
1331 // Forget about alpha.
1332 return ((uint32_t)((color & 0x00ffffffu) * ((1ull << 31) - 1))) >>
1333 (32 - PALETTE_INV_SIZE_BITS);
1334 }
1335
1336 // Sort palette in increasing order and prepare an inverse mapping array.
PrepareMapToPalette(const uint32_t palette[],int num_colors,uint32_t sorted[],uint32_t idx_map[])1337 static void PrepareMapToPalette(const uint32_t palette[], int num_colors,
1338 uint32_t sorted[], uint32_t idx_map[]) {
1339 int i;
1340 memcpy(sorted, palette, num_colors * sizeof(*sorted));
1341 qsort(sorted, num_colors, sizeof(*sorted), PaletteCompareColorsForQsort);
1342 for (i = 0; i < num_colors; ++i) {
1343 idx_map[SearchColorNoIdx(sorted, palette[i], num_colors)] = i;
1344 }
1345 }
1346
1347 // Use 1 pixel cache for ARGB pixels.
1348 #define APPLY_PALETTE_FOR(COLOR_INDEX) do { \
1349 uint32_t prev_pix = palette[0]; \
1350 uint32_t prev_idx = 0; \
1351 for (y = 0; y < height; ++y) { \
1352 for (x = 0; x < width; ++x) { \
1353 const uint32_t pix = src[x]; \
1354 if (pix != prev_pix) { \
1355 prev_idx = COLOR_INDEX; \
1356 prev_pix = pix; \
1357 } \
1358 tmp_row[x] = prev_idx; \
1359 } \
1360 VP8LBundleColorMap(tmp_row, width, xbits, dst); \
1361 src += src_stride; \
1362 dst += dst_stride; \
1363 } \
1364 } while (0)
1365
1366 // Remap argb values in src[] to packed palettes entries in dst[]
1367 // using 'row' as a temporary buffer of size 'width'.
1368 // We assume that all src[] values have a corresponding entry in the palette.
1369 // Note: src[] can be the same as dst[]
ApplyPalette(const uint32_t * src,uint32_t src_stride,uint32_t * dst,uint32_t dst_stride,const uint32_t * palette,int palette_size,int width,int height,int xbits)1370 static WebPEncodingError ApplyPalette(const uint32_t* src, uint32_t src_stride,
1371 uint32_t* dst, uint32_t dst_stride,
1372 const uint32_t* palette, int palette_size,
1373 int width, int height, int xbits) {
1374 // TODO(skal): this tmp buffer is not needed if VP8LBundleColorMap() can be
1375 // made to work in-place.
1376 uint8_t* const tmp_row = (uint8_t*)WebPSafeMalloc(width, sizeof(*tmp_row));
1377 int x, y;
1378
1379 if (tmp_row == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY;
1380
1381 if (palette_size < APPLY_PALETTE_GREEDY_MAX) {
1382 APPLY_PALETTE_FOR(SearchColorGreedy(palette, palette_size, pix));
1383 } else {
1384 int i, j;
1385 uint16_t buffer[PALETTE_INV_SIZE];
1386 uint32_t (*const hash_functions[])(uint32_t) = {
1387 ApplyPaletteHash0, ApplyPaletteHash1, ApplyPaletteHash2
1388 };
1389
1390 // Try to find a perfect hash function able to go from a color to an index
1391 // within 1 << PALETTE_INV_SIZE_BITS in order to build a hash map to go
1392 // from color to index in palette.
1393 for (i = 0; i < 3; ++i) {
1394 int use_LUT = 1;
1395 // Set each element in buffer to max uint16_t.
1396 memset(buffer, 0xff, sizeof(buffer));
1397 for (j = 0; j < palette_size; ++j) {
1398 const uint32_t ind = hash_functions[i](palette[j]);
1399 if (buffer[ind] != 0xffffu) {
1400 use_LUT = 0;
1401 break;
1402 } else {
1403 buffer[ind] = j;
1404 }
1405 }
1406 if (use_LUT) break;
1407 }
1408
1409 if (i == 0) {
1410 APPLY_PALETTE_FOR(buffer[ApplyPaletteHash0(pix)]);
1411 } else if (i == 1) {
1412 APPLY_PALETTE_FOR(buffer[ApplyPaletteHash1(pix)]);
1413 } else if (i == 2) {
1414 APPLY_PALETTE_FOR(buffer[ApplyPaletteHash2(pix)]);
1415 } else {
1416 uint32_t idx_map[MAX_PALETTE_SIZE];
1417 uint32_t palette_sorted[MAX_PALETTE_SIZE];
1418 PrepareMapToPalette(palette, palette_size, palette_sorted, idx_map);
1419 APPLY_PALETTE_FOR(
1420 idx_map[SearchColorNoIdx(palette_sorted, pix, palette_size)]);
1421 }
1422 }
1423 WebPSafeFree(tmp_row);
1424 return VP8_ENC_OK;
1425 }
1426 #undef APPLY_PALETTE_FOR
1427 #undef PALETTE_INV_SIZE_BITS
1428 #undef PALETTE_INV_SIZE
1429 #undef APPLY_PALETTE_GREEDY_MAX
1430
1431 // Note: Expects "enc->palette_" to be set properly.
MapImageFromPalette(VP8LEncoder * const enc,int in_place)1432 static WebPEncodingError MapImageFromPalette(VP8LEncoder* const enc,
1433 int in_place) {
1434 WebPEncodingError err = VP8_ENC_OK;
1435 const WebPPicture* const pic = enc->pic_;
1436 const int width = pic->width;
1437 const int height = pic->height;
1438 const uint32_t* const palette = enc->palette_;
1439 const uint32_t* src = in_place ? enc->argb_ : pic->argb;
1440 const int src_stride = in_place ? enc->current_width_ : pic->argb_stride;
1441 const int palette_size = enc->palette_size_;
1442 int xbits;
1443
1444 // Replace each input pixel by corresponding palette index.
1445 // This is done line by line.
1446 if (palette_size <= 4) {
1447 xbits = (palette_size <= 2) ? 3 : 2;
1448 } else {
1449 xbits = (palette_size <= 16) ? 1 : 0;
1450 }
1451
1452 err = AllocateTransformBuffer(enc, VP8LSubSampleSize(width, xbits), height);
1453 if (err != VP8_ENC_OK) return err;
1454
1455 err = ApplyPalette(src, src_stride,
1456 enc->argb_, enc->current_width_,
1457 palette, palette_size, width, height, xbits);
1458 enc->argb_content_ = kEncoderPalette;
1459 return err;
1460 }
1461
1462 // Save palette_[] to bitstream.
EncodePalette(VP8LBitWriter * const bw,int low_effort,VP8LEncoder * const enc)1463 static WebPEncodingError EncodePalette(VP8LBitWriter* const bw, int low_effort,
1464 VP8LEncoder* const enc) {
1465 int i;
1466 uint32_t tmp_palette[MAX_PALETTE_SIZE];
1467 const int palette_size = enc->palette_size_;
1468 const uint32_t* const palette = enc->palette_;
1469 VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
1470 VP8LPutBits(bw, COLOR_INDEXING_TRANSFORM, 2);
1471 assert(palette_size >= 1 && palette_size <= MAX_PALETTE_SIZE);
1472 VP8LPutBits(bw, palette_size - 1, 8);
1473 for (i = palette_size - 1; i >= 1; --i) {
1474 tmp_palette[i] = VP8LSubPixels(palette[i], palette[i - 1]);
1475 }
1476 tmp_palette[0] = palette[0];
1477 return EncodeImageNoHuffman(bw, tmp_palette, &enc->hash_chain_,
1478 &enc->refs_[0], palette_size, 1, /*quality=*/20,
1479 low_effort);
1480 }
1481
1482 // -----------------------------------------------------------------------------
1483 // VP8LEncoder
1484
VP8LEncoderNew(const WebPConfig * const config,const WebPPicture * const picture)1485 static VP8LEncoder* VP8LEncoderNew(const WebPConfig* const config,
1486 const WebPPicture* const picture) {
1487 VP8LEncoder* const enc = (VP8LEncoder*)WebPSafeCalloc(1ULL, sizeof(*enc));
1488 if (enc == NULL) {
1489 WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
1490 return NULL;
1491 }
1492 enc->config_ = config;
1493 enc->pic_ = picture;
1494 enc->argb_content_ = kEncoderNone;
1495
1496 VP8LEncDspInit();
1497
1498 return enc;
1499 }
1500
VP8LEncoderDelete(VP8LEncoder * enc)1501 static void VP8LEncoderDelete(VP8LEncoder* enc) {
1502 if (enc != NULL) {
1503 int i;
1504 VP8LHashChainClear(&enc->hash_chain_);
1505 for (i = 0; i < 4; ++i) VP8LBackwardRefsClear(&enc->refs_[i]);
1506 ClearTransformBuffer(enc);
1507 WebPSafeFree(enc);
1508 }
1509 }
1510
1511 // -----------------------------------------------------------------------------
1512 // Main call
1513
1514 typedef struct {
1515 const WebPConfig* config_;
1516 const WebPPicture* picture_;
1517 VP8LBitWriter* bw_;
1518 VP8LEncoder* enc_;
1519 int use_cache_;
1520 CrunchConfig crunch_configs_[CRUNCH_CONFIGS_MAX];
1521 int num_crunch_configs_;
1522 int red_and_blue_always_zero_;
1523 WebPEncodingError err_;
1524 WebPAuxStats* stats_;
1525 } StreamEncodeContext;
1526
EncodeStreamHook(void * input,void * data2)1527 static int EncodeStreamHook(void* input, void* data2) {
1528 StreamEncodeContext* const params = (StreamEncodeContext*)input;
1529 const WebPConfig* const config = params->config_;
1530 const WebPPicture* const picture = params->picture_;
1531 VP8LBitWriter* const bw = params->bw_;
1532 VP8LEncoder* const enc = params->enc_;
1533 const int use_cache = params->use_cache_;
1534 const CrunchConfig* const crunch_configs = params->crunch_configs_;
1535 const int num_crunch_configs = params->num_crunch_configs_;
1536 const int red_and_blue_always_zero = params->red_and_blue_always_zero_;
1537 #if !defined(WEBP_DISABLE_STATS)
1538 WebPAuxStats* const stats = params->stats_;
1539 #endif
1540 WebPEncodingError err = VP8_ENC_OK;
1541 const int quality = (int)config->quality;
1542 const int low_effort = (config->method == 0);
1543 #if (WEBP_NEAR_LOSSLESS == 1)
1544 const int width = picture->width;
1545 #endif
1546 const int height = picture->height;
1547 const size_t byte_position = VP8LBitWriterNumBytes(bw);
1548 #if (WEBP_NEAR_LOSSLESS == 1)
1549 int use_near_lossless = 0;
1550 #endif
1551 int hdr_size = 0;
1552 int data_size = 0;
1553 int use_delta_palette = 0;
1554 int idx;
1555 size_t best_size = ~(size_t)0;
1556 VP8LBitWriter bw_init = *bw, bw_best;
1557 (void)data2;
1558
1559 if (!VP8LBitWriterInit(&bw_best, 0) ||
1560 (num_crunch_configs > 1 && !VP8LBitWriterClone(bw, &bw_best))) {
1561 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1562 goto Error;
1563 }
1564
1565 for (idx = 0; idx < num_crunch_configs; ++idx) {
1566 const int entropy_idx = crunch_configs[idx].entropy_idx_;
1567 enc->use_palette_ =
1568 (entropy_idx == kPalette) || (entropy_idx == kPaletteAndSpatial);
1569 enc->use_subtract_green_ =
1570 (entropy_idx == kSubGreen) || (entropy_idx == kSpatialSubGreen);
1571 enc->use_predict_ = (entropy_idx == kSpatial) ||
1572 (entropy_idx == kSpatialSubGreen) ||
1573 (entropy_idx == kPaletteAndSpatial);
1574 if (low_effort) {
1575 enc->use_cross_color_ = 0;
1576 } else {
1577 enc->use_cross_color_ = red_and_blue_always_zero ? 0 : enc->use_predict_;
1578 }
1579 // Reset any parameter in the encoder that is set in the previous iteration.
1580 enc->cache_bits_ = 0;
1581 VP8LBackwardRefsClear(&enc->refs_[0]);
1582 VP8LBackwardRefsClear(&enc->refs_[1]);
1583
1584 #if (WEBP_NEAR_LOSSLESS == 1)
1585 // Apply near-lossless preprocessing.
1586 use_near_lossless = (config->near_lossless < 100) && !enc->use_palette_ &&
1587 !enc->use_predict_;
1588 if (use_near_lossless) {
1589 err = AllocateTransformBuffer(enc, width, height);
1590 if (err != VP8_ENC_OK) goto Error;
1591 if ((enc->argb_content_ != kEncoderNearLossless) &&
1592 !VP8ApplyNearLossless(picture, config->near_lossless, enc->argb_)) {
1593 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1594 goto Error;
1595 }
1596 enc->argb_content_ = kEncoderNearLossless;
1597 } else {
1598 enc->argb_content_ = kEncoderNone;
1599 }
1600 #else
1601 enc->argb_content_ = kEncoderNone;
1602 #endif
1603
1604 // Encode palette
1605 if (enc->use_palette_) {
1606 err = EncodePalette(bw, low_effort, enc);
1607 if (err != VP8_ENC_OK) goto Error;
1608 err = MapImageFromPalette(enc, use_delta_palette);
1609 if (err != VP8_ENC_OK) goto Error;
1610 // If using a color cache, do not have it bigger than the number of
1611 // colors.
1612 if (use_cache && enc->palette_size_ < (1 << MAX_COLOR_CACHE_BITS)) {
1613 enc->cache_bits_ = BitsLog2Floor(enc->palette_size_) + 1;
1614 }
1615 }
1616 if (!use_delta_palette) {
1617 // In case image is not packed.
1618 if (enc->argb_content_ != kEncoderNearLossless &&
1619 enc->argb_content_ != kEncoderPalette) {
1620 err = MakeInputImageCopy(enc);
1621 if (err != VP8_ENC_OK) goto Error;
1622 }
1623
1624 // -----------------------------------------------------------------------
1625 // Apply transforms and write transform data.
1626
1627 if (enc->use_subtract_green_) {
1628 ApplySubtractGreen(enc, enc->current_width_, height, bw);
1629 }
1630
1631 if (enc->use_predict_) {
1632 err = ApplyPredictFilter(enc, enc->current_width_, height, quality,
1633 low_effort, enc->use_subtract_green_, bw);
1634 if (err != VP8_ENC_OK) goto Error;
1635 }
1636
1637 if (enc->use_cross_color_) {
1638 err = ApplyCrossColorFilter(enc, enc->current_width_, height, quality,
1639 low_effort, bw);
1640 if (err != VP8_ENC_OK) goto Error;
1641 }
1642 }
1643
1644 VP8LPutBits(bw, !TRANSFORM_PRESENT, 1); // No more transforms.
1645
1646 // -------------------------------------------------------------------------
1647 // Encode and write the transformed image.
1648 err = EncodeImageInternal(bw, enc->argb_, &enc->hash_chain_, enc->refs_,
1649 enc->current_width_, height, quality, low_effort,
1650 use_cache, &crunch_configs[idx],
1651 &enc->cache_bits_, enc->histo_bits_,
1652 byte_position, &hdr_size, &data_size);
1653 if (err != VP8_ENC_OK) goto Error;
1654
1655 // If we are better than what we already have.
1656 if (VP8LBitWriterNumBytes(bw) < best_size) {
1657 best_size = VP8LBitWriterNumBytes(bw);
1658 // Store the BitWriter.
1659 VP8LBitWriterSwap(bw, &bw_best);
1660 #if !defined(WEBP_DISABLE_STATS)
1661 // Update the stats.
1662 if (stats != NULL) {
1663 stats->lossless_features = 0;
1664 if (enc->use_predict_) stats->lossless_features |= 1;
1665 if (enc->use_cross_color_) stats->lossless_features |= 2;
1666 if (enc->use_subtract_green_) stats->lossless_features |= 4;
1667 if (enc->use_palette_) stats->lossless_features |= 8;
1668 stats->histogram_bits = enc->histo_bits_;
1669 stats->transform_bits = enc->transform_bits_;
1670 stats->cache_bits = enc->cache_bits_;
1671 stats->palette_size = enc->palette_size_;
1672 stats->lossless_size = (int)(best_size - byte_position);
1673 stats->lossless_hdr_size = hdr_size;
1674 stats->lossless_data_size = data_size;
1675 }
1676 #endif
1677 }
1678 // Reset the bit writer for the following iteration if any.
1679 if (num_crunch_configs > 1) VP8LBitWriterReset(&bw_init, bw);
1680 }
1681 VP8LBitWriterSwap(&bw_best, bw);
1682
1683 Error:
1684 VP8LBitWriterWipeOut(&bw_best);
1685 params->err_ = err;
1686 // The hook should return false in case of error.
1687 return (err == VP8_ENC_OK);
1688 }
1689
VP8LEncodeStream(const WebPConfig * const config,const WebPPicture * const picture,VP8LBitWriter * const bw_main,int use_cache)1690 WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
1691 const WebPPicture* const picture,
1692 VP8LBitWriter* const bw_main,
1693 int use_cache) {
1694 WebPEncodingError err = VP8_ENC_OK;
1695 VP8LEncoder* const enc_main = VP8LEncoderNew(config, picture);
1696 VP8LEncoder* enc_side = NULL;
1697 CrunchConfig crunch_configs[CRUNCH_CONFIGS_MAX];
1698 int num_crunch_configs_main, num_crunch_configs_side = 0;
1699 int idx;
1700 int red_and_blue_always_zero = 0;
1701 WebPWorker worker_main, worker_side;
1702 StreamEncodeContext params_main, params_side;
1703 // The main thread uses picture->stats, the side thread uses stats_side.
1704 WebPAuxStats stats_side;
1705 VP8LBitWriter bw_side;
1706 const WebPWorkerInterface* const worker_interface = WebPGetWorkerInterface();
1707 int ok_main;
1708
1709 // Analyze image (entropy, num_palettes etc)
1710 if (enc_main == NULL ||
1711 !EncoderAnalyze(enc_main, crunch_configs, &num_crunch_configs_main,
1712 &red_and_blue_always_zero) ||
1713 !EncoderInit(enc_main) || !VP8LBitWriterInit(&bw_side, 0)) {
1714 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1715 goto Error;
1716 }
1717
1718 // Split the configs between the main and side threads (if any).
1719 if (config->thread_level > 0) {
1720 num_crunch_configs_side = num_crunch_configs_main / 2;
1721 for (idx = 0; idx < num_crunch_configs_side; ++idx) {
1722 params_side.crunch_configs_[idx] =
1723 crunch_configs[num_crunch_configs_main - num_crunch_configs_side +
1724 idx];
1725 }
1726 params_side.num_crunch_configs_ = num_crunch_configs_side;
1727 }
1728 num_crunch_configs_main -= num_crunch_configs_side;
1729 for (idx = 0; idx < num_crunch_configs_main; ++idx) {
1730 params_main.crunch_configs_[idx] = crunch_configs[idx];
1731 }
1732 params_main.num_crunch_configs_ = num_crunch_configs_main;
1733
1734 // Fill in the parameters for the thread workers.
1735 {
1736 const int params_size = (num_crunch_configs_side > 0) ? 2 : 1;
1737 for (idx = 0; idx < params_size; ++idx) {
1738 // Create the parameters for each worker.
1739 WebPWorker* const worker = (idx == 0) ? &worker_main : &worker_side;
1740 StreamEncodeContext* const param =
1741 (idx == 0) ? ¶ms_main : ¶ms_side;
1742 param->config_ = config;
1743 param->picture_ = picture;
1744 param->use_cache_ = use_cache;
1745 param->red_and_blue_always_zero_ = red_and_blue_always_zero;
1746 if (idx == 0) {
1747 param->stats_ = picture->stats;
1748 param->bw_ = bw_main;
1749 param->enc_ = enc_main;
1750 } else {
1751 param->stats_ = (picture->stats == NULL) ? NULL : &stats_side;
1752 // Create a side bit writer.
1753 if (!VP8LBitWriterClone(bw_main, &bw_side)) {
1754 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1755 goto Error;
1756 }
1757 param->bw_ = &bw_side;
1758 // Create a side encoder.
1759 enc_side = VP8LEncoderNew(config, picture);
1760 if (enc_side == NULL || !EncoderInit(enc_side)) {
1761 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1762 goto Error;
1763 }
1764 // Copy the values that were computed for the main encoder.
1765 enc_side->histo_bits_ = enc_main->histo_bits_;
1766 enc_side->transform_bits_ = enc_main->transform_bits_;
1767 enc_side->palette_size_ = enc_main->palette_size_;
1768 memcpy(enc_side->palette_, enc_main->palette_,
1769 sizeof(enc_main->palette_));
1770 param->enc_ = enc_side;
1771 }
1772 // Create the workers.
1773 worker_interface->Init(worker);
1774 worker->data1 = param;
1775 worker->data2 = NULL;
1776 worker->hook = EncodeStreamHook;
1777 }
1778 }
1779
1780 // Start the second thread if needed.
1781 if (num_crunch_configs_side != 0) {
1782 if (!worker_interface->Reset(&worker_side)) {
1783 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1784 goto Error;
1785 }
1786 #if !defined(WEBP_DISABLE_STATS)
1787 // This line is here and not in the param initialization above to remove a
1788 // Clang static analyzer warning.
1789 if (picture->stats != NULL) {
1790 memcpy(&stats_side, picture->stats, sizeof(stats_side));
1791 }
1792 #endif
1793 // This line is only useful to remove a Clang static analyzer warning.
1794 params_side.err_ = VP8_ENC_OK;
1795 worker_interface->Launch(&worker_side);
1796 }
1797 // Execute the main thread.
1798 worker_interface->Execute(&worker_main);
1799 ok_main = worker_interface->Sync(&worker_main);
1800 worker_interface->End(&worker_main);
1801 if (num_crunch_configs_side != 0) {
1802 // Wait for the second thread.
1803 const int ok_side = worker_interface->Sync(&worker_side);
1804 worker_interface->End(&worker_side);
1805 if (!ok_main || !ok_side) {
1806 err = ok_main ? params_side.err_ : params_main.err_;
1807 goto Error;
1808 }
1809 if (VP8LBitWriterNumBytes(&bw_side) < VP8LBitWriterNumBytes(bw_main)) {
1810 VP8LBitWriterSwap(bw_main, &bw_side);
1811 #if !defined(WEBP_DISABLE_STATS)
1812 if (picture->stats != NULL) {
1813 memcpy(picture->stats, &stats_side, sizeof(*picture->stats));
1814 }
1815 #endif
1816 }
1817 } else {
1818 if (!ok_main) {
1819 err = params_main.err_;
1820 goto Error;
1821 }
1822 }
1823
1824 Error:
1825 VP8LBitWriterWipeOut(&bw_side);
1826 VP8LEncoderDelete(enc_main);
1827 VP8LEncoderDelete(enc_side);
1828 return err;
1829 }
1830
1831 #undef CRUNCH_CONFIGS_MAX
1832 #undef CRUNCH_SUBCONFIGS_MAX
1833
VP8LEncodeImage(const WebPConfig * const config,const WebPPicture * const picture)1834 int VP8LEncodeImage(const WebPConfig* const config,
1835 const WebPPicture* const picture) {
1836 int width, height;
1837 int has_alpha;
1838 size_t coded_size;
1839 int percent = 0;
1840 int initial_size;
1841 WebPEncodingError err = VP8_ENC_OK;
1842 VP8LBitWriter bw;
1843
1844 if (picture == NULL) return 0;
1845
1846 if (config == NULL || picture->argb == NULL) {
1847 err = VP8_ENC_ERROR_NULL_PARAMETER;
1848 WebPEncodingSetError(picture, err);
1849 return 0;
1850 }
1851
1852 width = picture->width;
1853 height = picture->height;
1854 // Initialize BitWriter with size corresponding to 16 bpp to photo images and
1855 // 8 bpp for graphical images.
1856 initial_size = (config->image_hint == WEBP_HINT_GRAPH) ?
1857 width * height : width * height * 2;
1858 if (!VP8LBitWriterInit(&bw, initial_size)) {
1859 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1860 goto Error;
1861 }
1862
1863 if (!WebPReportProgress(picture, 1, &percent)) {
1864 UserAbort:
1865 err = VP8_ENC_ERROR_USER_ABORT;
1866 goto Error;
1867 }
1868 // Reset stats (for pure lossless coding)
1869 if (picture->stats != NULL) {
1870 WebPAuxStats* const stats = picture->stats;
1871 memset(stats, 0, sizeof(*stats));
1872 stats->PSNR[0] = 99.f;
1873 stats->PSNR[1] = 99.f;
1874 stats->PSNR[2] = 99.f;
1875 stats->PSNR[3] = 99.f;
1876 stats->PSNR[4] = 99.f;
1877 }
1878
1879 // Write image size.
1880 if (!WriteImageSize(picture, &bw)) {
1881 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1882 goto Error;
1883 }
1884
1885 has_alpha = WebPPictureHasTransparency(picture);
1886 // Write the non-trivial Alpha flag and lossless version.
1887 if (!WriteRealAlphaAndVersion(&bw, has_alpha)) {
1888 err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1889 goto Error;
1890 }
1891
1892 if (!WebPReportProgress(picture, 5, &percent)) goto UserAbort;
1893
1894 // Encode main image stream.
1895 err = VP8LEncodeStream(config, picture, &bw, 1 /*use_cache*/);
1896 if (err != VP8_ENC_OK) goto Error;
1897
1898 if (!WebPReportProgress(picture, 90, &percent)) goto UserAbort;
1899
1900 // Finish the RIFF chunk.
1901 err = WriteImage(picture, &bw, &coded_size);
1902 if (err != VP8_ENC_OK) goto Error;
1903
1904 if (!WebPReportProgress(picture, 100, &percent)) goto UserAbort;
1905
1906 #if !defined(WEBP_DISABLE_STATS)
1907 // Save size.
1908 if (picture->stats != NULL) {
1909 picture->stats->coded_size += (int)coded_size;
1910 picture->stats->lossless_size = (int)coded_size;
1911 }
1912 #endif
1913
1914 if (picture->extra_info != NULL) {
1915 const int mb_w = (width + 15) >> 4;
1916 const int mb_h = (height + 15) >> 4;
1917 memset(picture->extra_info, 0, mb_w * mb_h * sizeof(*picture->extra_info));
1918 }
1919
1920 Error:
1921 if (bw.error_) err = VP8_ENC_ERROR_OUT_OF_MEMORY;
1922 VP8LBitWriterWipeOut(&bw);
1923 if (err != VP8_ENC_OK) {
1924 WebPEncodingSetError(picture, err);
1925 return 0;
1926 }
1927 return 1;
1928 }
1929
1930 //------------------------------------------------------------------------------
1931