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 <stdio.h> 17#include <stdlib.h> 18 19#include "./backward_references.h" 20#include "./vp8enci.h" 21#include "./vp8li.h" 22#include "../dsp/lossless.h" 23#include "../utils/bit_writer.h" 24#include "../utils/huffman_encode.h" 25#include "../utils/utils.h" 26#include "webp/format_constants.h" 27 28#define PALETTE_KEY_RIGHT_SHIFT 22 // Key for 1K buffer. 29#define MAX_HUFF_IMAGE_SIZE (16 * 1024 * 1024) 30#define MAX_COLORS_FOR_GRAPH 64 31 32// ----------------------------------------------------------------------------- 33// Palette 34 35static int CompareColors(const void* p1, const void* p2) { 36 const uint32_t a = *(const uint32_t*)p1; 37 const uint32_t b = *(const uint32_t*)p2; 38 assert(a != b); 39 return (a < b) ? -1 : 1; 40} 41 42// If number of colors in the image is less than or equal to MAX_PALETTE_SIZE, 43// creates a palette and returns true, else returns false. 44static int AnalyzeAndCreatePalette(const WebPPicture* const pic, 45 uint32_t palette[MAX_PALETTE_SIZE], 46 int* const palette_size) { 47 int i, x, y, key; 48 int num_colors = 0; 49 uint8_t in_use[MAX_PALETTE_SIZE * 4] = { 0 }; 50 uint32_t colors[MAX_PALETTE_SIZE * 4]; 51 static const uint32_t kHashMul = 0x1e35a7bd; 52 const uint32_t* argb = pic->argb; 53 const int width = pic->width; 54 const int height = pic->height; 55 uint32_t last_pix = ~argb[0]; // so we're sure that last_pix != argb[0] 56 57 for (y = 0; y < height; ++y) { 58 for (x = 0; x < width; ++x) { 59 if (argb[x] == last_pix) { 60 continue; 61 } 62 last_pix = argb[x]; 63 key = (kHashMul * last_pix) >> PALETTE_KEY_RIGHT_SHIFT; 64 while (1) { 65 if (!in_use[key]) { 66 colors[key] = last_pix; 67 in_use[key] = 1; 68 ++num_colors; 69 if (num_colors > MAX_PALETTE_SIZE) { 70 return 0; 71 } 72 break; 73 } else if (colors[key] == last_pix) { 74 // The color is already there. 75 break; 76 } else { 77 // Some other color sits there. 78 // Do linear conflict resolution. 79 ++key; 80 key &= (MAX_PALETTE_SIZE * 4 - 1); // key mask for 1K buffer. 81 } 82 } 83 } 84 argb += pic->argb_stride; 85 } 86 87 // TODO(skal): could we reuse in_use[] to speed up EncodePalette()? 88 num_colors = 0; 89 for (i = 0; i < (int)(sizeof(in_use) / sizeof(in_use[0])); ++i) { 90 if (in_use[i]) { 91 palette[num_colors] = colors[i]; 92 ++num_colors; 93 } 94 } 95 96 qsort(palette, num_colors, sizeof(*palette), CompareColors); 97 *palette_size = num_colors; 98 return 1; 99} 100 101static int AnalyzeEntropy(const uint32_t* argb, 102 int width, int height, int argb_stride, 103 double* const nonpredicted_bits, 104 double* const predicted_bits) { 105 int x, y; 106 const uint32_t* last_line = NULL; 107 uint32_t last_pix = argb[0]; // so we're sure that pix_diff == 0 108 109 VP8LHistogramSet* const histo_set = VP8LAllocateHistogramSet(2, 0); 110 if (histo_set == NULL) return 0; 111 112 for (y = 0; y < height; ++y) { 113 for (x = 0; x < width; ++x) { 114 const uint32_t pix = argb[x]; 115 const uint32_t pix_diff = VP8LSubPixels(pix, last_pix); 116 if (pix_diff == 0) continue; 117 if (last_line != NULL && pix == last_line[x]) { 118 continue; 119 } 120 last_pix = pix; 121 { 122 const PixOrCopy pix_token = PixOrCopyCreateLiteral(pix); 123 const PixOrCopy pix_diff_token = PixOrCopyCreateLiteral(pix_diff); 124 VP8LHistogramAddSinglePixOrCopy(histo_set->histograms[0], &pix_token); 125 VP8LHistogramAddSinglePixOrCopy(histo_set->histograms[1], 126 &pix_diff_token); 127 } 128 } 129 last_line = argb; 130 argb += argb_stride; 131 } 132 *nonpredicted_bits = VP8LHistogramEstimateBitsBulk(histo_set->histograms[0]); 133 *predicted_bits = VP8LHistogramEstimateBitsBulk(histo_set->histograms[1]); 134 VP8LFreeHistogramSet(histo_set); 135 return 1; 136} 137 138static int AnalyzeAndInit(VP8LEncoder* const enc, WebPImageHint image_hint) { 139 const WebPPicture* const pic = enc->pic_; 140 const int width = pic->width; 141 const int height = pic->height; 142 const int pix_cnt = width * height; 143 // we round the block size up, so we're guaranteed to have 144 // at max MAX_REFS_BLOCK_PER_IMAGE blocks used: 145 int refs_block_size = (pix_cnt - 1) / MAX_REFS_BLOCK_PER_IMAGE + 1; 146 assert(pic != NULL && pic->argb != NULL); 147 148 enc->use_palette_ = 149 AnalyzeAndCreatePalette(pic, enc->palette_, &enc->palette_size_); 150 151 if (image_hint == WEBP_HINT_GRAPH) { 152 if (enc->use_palette_ && enc->palette_size_ < MAX_COLORS_FOR_GRAPH) { 153 enc->use_palette_ = 0; 154 } 155 } 156 157 if (!enc->use_palette_) { 158 if (image_hint == WEBP_HINT_PHOTO) { 159 enc->use_predict_ = 1; 160 enc->use_cross_color_ = 1; 161 } else { 162 double non_pred_entropy, pred_entropy; 163 if (!AnalyzeEntropy(pic->argb, width, height, pic->argb_stride, 164 &non_pred_entropy, &pred_entropy)) { 165 return 0; 166 } 167 if (pred_entropy < 0.95 * non_pred_entropy) { 168 enc->use_predict_ = 1; 169 enc->use_cross_color_ = 1; 170 } 171 } 172 } 173 if (!VP8LHashChainInit(&enc->hash_chain_, pix_cnt)) return 0; 174 175 // palette-friendly input typically uses less literals 176 // -> reduce block size a bit 177 if (enc->use_palette_) refs_block_size /= 2; 178 VP8LBackwardRefsInit(&enc->refs_[0], refs_block_size); 179 VP8LBackwardRefsInit(&enc->refs_[1], refs_block_size); 180 181 return 1; 182} 183 184// Returns false in case of memory error. 185static int GetHuffBitLengthsAndCodes( 186 const VP8LHistogramSet* const histogram_image, 187 HuffmanTreeCode* const huffman_codes) { 188 int i, k; 189 int ok = 0; 190 uint64_t total_length_size = 0; 191 uint8_t* mem_buf = NULL; 192 const int histogram_image_size = histogram_image->size; 193 int max_num_symbols = 0; 194 uint8_t* buf_rle = NULL; 195 HuffmanTree* huff_tree = NULL; 196 197 // Iterate over all histograms and get the aggregate number of codes used. 198 for (i = 0; i < histogram_image_size; ++i) { 199 const VP8LHistogram* const histo = histogram_image->histograms[i]; 200 HuffmanTreeCode* const codes = &huffman_codes[5 * i]; 201 for (k = 0; k < 5; ++k) { 202 const int num_symbols = 203 (k == 0) ? VP8LHistogramNumCodes(histo->palette_code_bits_) : 204 (k == 4) ? NUM_DISTANCE_CODES : 256; 205 codes[k].num_symbols = num_symbols; 206 total_length_size += num_symbols; 207 } 208 } 209 210 // Allocate and Set Huffman codes. 211 { 212 uint16_t* codes; 213 uint8_t* lengths; 214 mem_buf = (uint8_t*)WebPSafeCalloc(total_length_size, 215 sizeof(*lengths) + sizeof(*codes)); 216 if (mem_buf == NULL) goto End; 217 218 codes = (uint16_t*)mem_buf; 219 lengths = (uint8_t*)&codes[total_length_size]; 220 for (i = 0; i < 5 * histogram_image_size; ++i) { 221 const int bit_length = huffman_codes[i].num_symbols; 222 huffman_codes[i].codes = codes; 223 huffman_codes[i].code_lengths = lengths; 224 codes += bit_length; 225 lengths += bit_length; 226 if (max_num_symbols < bit_length) { 227 max_num_symbols = bit_length; 228 } 229 } 230 } 231 232 buf_rle = (uint8_t*)WebPSafeMalloc(1ULL, max_num_symbols); 233 huff_tree = (HuffmanTree*)WebPSafeMalloc(3ULL * max_num_symbols, 234 sizeof(*huff_tree)); 235 if (buf_rle == NULL || huff_tree == NULL) goto End; 236 237 // Create Huffman trees. 238 for (i = 0; i < histogram_image_size; ++i) { 239 HuffmanTreeCode* const codes = &huffman_codes[5 * i]; 240 VP8LHistogram* const histo = histogram_image->histograms[i]; 241 VP8LCreateHuffmanTree(histo->literal_, 15, buf_rle, huff_tree, codes + 0); 242 VP8LCreateHuffmanTree(histo->red_, 15, buf_rle, huff_tree, codes + 1); 243 VP8LCreateHuffmanTree(histo->blue_, 15, buf_rle, huff_tree, codes + 2); 244 VP8LCreateHuffmanTree(histo->alpha_, 15, buf_rle, huff_tree, codes + 3); 245 VP8LCreateHuffmanTree(histo->distance_, 15, buf_rle, huff_tree, codes + 4); 246 } 247 ok = 1; 248 End: 249 WebPSafeFree(huff_tree); 250 WebPSafeFree(buf_rle); 251 if (!ok) { 252 WebPSafeFree(mem_buf); 253 memset(huffman_codes, 0, 5 * histogram_image_size * sizeof(*huffman_codes)); 254 } 255 return ok; 256} 257 258static void StoreHuffmanTreeOfHuffmanTreeToBitMask( 259 VP8LBitWriter* const bw, const uint8_t* code_length_bitdepth) { 260 // RFC 1951 will calm you down if you are worried about this funny sequence. 261 // This sequence is tuned from that, but more weighted for lower symbol count, 262 // and more spiking histograms. 263 static const uint8_t kStorageOrder[CODE_LENGTH_CODES] = { 264 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 265 }; 266 int i; 267 // Throw away trailing zeros: 268 int codes_to_store = CODE_LENGTH_CODES; 269 for (; codes_to_store > 4; --codes_to_store) { 270 if (code_length_bitdepth[kStorageOrder[codes_to_store - 1]] != 0) { 271 break; 272 } 273 } 274 VP8LWriteBits(bw, 4, codes_to_store - 4); 275 for (i = 0; i < codes_to_store; ++i) { 276 VP8LWriteBits(bw, 3, code_length_bitdepth[kStorageOrder[i]]); 277 } 278} 279 280static void ClearHuffmanTreeIfOnlyOneSymbol( 281 HuffmanTreeCode* const huffman_code) { 282 int k; 283 int count = 0; 284 for (k = 0; k < huffman_code->num_symbols; ++k) { 285 if (huffman_code->code_lengths[k] != 0) { 286 ++count; 287 if (count > 1) return; 288 } 289 } 290 for (k = 0; k < huffman_code->num_symbols; ++k) { 291 huffman_code->code_lengths[k] = 0; 292 huffman_code->codes[k] = 0; 293 } 294} 295 296static void StoreHuffmanTreeToBitMask( 297 VP8LBitWriter* const bw, 298 const HuffmanTreeToken* const tokens, const int num_tokens, 299 const HuffmanTreeCode* const huffman_code) { 300 int i; 301 for (i = 0; i < num_tokens; ++i) { 302 const int ix = tokens[i].code; 303 const int extra_bits = tokens[i].extra_bits; 304 VP8LWriteBits(bw, huffman_code->code_lengths[ix], huffman_code->codes[ix]); 305 switch (ix) { 306 case 16: 307 VP8LWriteBits(bw, 2, extra_bits); 308 break; 309 case 17: 310 VP8LWriteBits(bw, 3, extra_bits); 311 break; 312 case 18: 313 VP8LWriteBits(bw, 7, extra_bits); 314 break; 315 } 316 } 317} 318 319// 'huff_tree' and 'tokens' are pre-alloacted buffers. 320static void StoreFullHuffmanCode(VP8LBitWriter* const bw, 321 HuffmanTree* const huff_tree, 322 HuffmanTreeToken* const tokens, 323 const HuffmanTreeCode* const tree) { 324 uint8_t code_length_bitdepth[CODE_LENGTH_CODES] = { 0 }; 325 uint16_t code_length_bitdepth_symbols[CODE_LENGTH_CODES] = { 0 }; 326 const int max_tokens = tree->num_symbols; 327 int num_tokens; 328 HuffmanTreeCode huffman_code; 329 huffman_code.num_symbols = CODE_LENGTH_CODES; 330 huffman_code.code_lengths = code_length_bitdepth; 331 huffman_code.codes = code_length_bitdepth_symbols; 332 333 VP8LWriteBits(bw, 1, 0); 334 num_tokens = VP8LCreateCompressedHuffmanTree(tree, tokens, max_tokens); 335 { 336 uint32_t histogram[CODE_LENGTH_CODES] = { 0 }; 337 uint8_t buf_rle[CODE_LENGTH_CODES] = { 0 }; 338 int i; 339 for (i = 0; i < num_tokens; ++i) { 340 ++histogram[tokens[i].code]; 341 } 342 343 VP8LCreateHuffmanTree(histogram, 7, buf_rle, huff_tree, &huffman_code); 344 } 345 346 StoreHuffmanTreeOfHuffmanTreeToBitMask(bw, code_length_bitdepth); 347 ClearHuffmanTreeIfOnlyOneSymbol(&huffman_code); 348 { 349 int trailing_zero_bits = 0; 350 int trimmed_length = num_tokens; 351 int write_trimmed_length; 352 int length; 353 int i = num_tokens; 354 while (i-- > 0) { 355 const int ix = tokens[i].code; 356 if (ix == 0 || ix == 17 || ix == 18) { 357 --trimmed_length; // discount trailing zeros 358 trailing_zero_bits += code_length_bitdepth[ix]; 359 if (ix == 17) { 360 trailing_zero_bits += 3; 361 } else if (ix == 18) { 362 trailing_zero_bits += 7; 363 } 364 } else { 365 break; 366 } 367 } 368 write_trimmed_length = (trimmed_length > 1 && trailing_zero_bits > 12); 369 length = write_trimmed_length ? trimmed_length : num_tokens; 370 VP8LWriteBits(bw, 1, write_trimmed_length); 371 if (write_trimmed_length) { 372 const int nbits = VP8LBitsLog2Ceiling(trimmed_length - 1); 373 const int nbitpairs = (nbits == 0) ? 1 : (nbits + 1) / 2; 374 VP8LWriteBits(bw, 3, nbitpairs - 1); 375 assert(trimmed_length >= 2); 376 VP8LWriteBits(bw, nbitpairs * 2, trimmed_length - 2); 377 } 378 StoreHuffmanTreeToBitMask(bw, tokens, length, &huffman_code); 379 } 380} 381 382// 'huff_tree' and 'tokens' are pre-alloacted buffers. 383static void StoreHuffmanCode(VP8LBitWriter* const bw, 384 HuffmanTree* const huff_tree, 385 HuffmanTreeToken* const tokens, 386 const HuffmanTreeCode* const huffman_code) { 387 int i; 388 int count = 0; 389 int symbols[2] = { 0, 0 }; 390 const int kMaxBits = 8; 391 const int kMaxSymbol = 1 << kMaxBits; 392 393 // Check whether it's a small tree. 394 for (i = 0; i < huffman_code->num_symbols && count < 3; ++i) { 395 if (huffman_code->code_lengths[i] != 0) { 396 if (count < 2) symbols[count] = i; 397 ++count; 398 } 399 } 400 401 if (count == 0) { // emit minimal tree for empty cases 402 // bits: small tree marker: 1, count-1: 0, large 8-bit code: 0, code: 0 403 VP8LWriteBits(bw, 4, 0x01); 404 } else if (count <= 2 && symbols[0] < kMaxSymbol && symbols[1] < kMaxSymbol) { 405 VP8LWriteBits(bw, 1, 1); // Small tree marker to encode 1 or 2 symbols. 406 VP8LWriteBits(bw, 1, count - 1); 407 if (symbols[0] <= 1) { 408 VP8LWriteBits(bw, 1, 0); // Code bit for small (1 bit) symbol value. 409 VP8LWriteBits(bw, 1, symbols[0]); 410 } else { 411 VP8LWriteBits(bw, 1, 1); 412 VP8LWriteBits(bw, 8, symbols[0]); 413 } 414 if (count == 2) { 415 VP8LWriteBits(bw, 8, symbols[1]); 416 } 417 } else { 418 StoreFullHuffmanCode(bw, huff_tree, tokens, huffman_code); 419 } 420} 421 422static void WriteHuffmanCode(VP8LBitWriter* const bw, 423 const HuffmanTreeCode* const code, 424 int code_index) { 425 const int depth = code->code_lengths[code_index]; 426 const int symbol = code->codes[code_index]; 427 VP8LWriteBits(bw, depth, symbol); 428} 429 430static WebPEncodingError StoreImageToBitMask( 431 VP8LBitWriter* const bw, int width, int histo_bits, 432 VP8LBackwardRefs* const refs, 433 const uint16_t* histogram_symbols, 434 const HuffmanTreeCode* const huffman_codes) { 435 // x and y trace the position in the image. 436 int x = 0; 437 int y = 0; 438 const int histo_xsize = histo_bits ? VP8LSubSampleSize(width, histo_bits) : 1; 439 VP8LRefsCursor c = VP8LRefsCursorInit(refs); 440 while (VP8LRefsCursorOk(&c)) { 441 const PixOrCopy* const v = c.cur_pos; 442 const int histogram_ix = histogram_symbols[histo_bits ? 443 (y >> histo_bits) * histo_xsize + 444 (x >> histo_bits) : 0]; 445 const HuffmanTreeCode* const codes = huffman_codes + 5 * histogram_ix; 446 if (PixOrCopyIsCacheIdx(v)) { 447 const int code = PixOrCopyCacheIdx(v); 448 const int literal_ix = 256 + NUM_LENGTH_CODES + code; 449 WriteHuffmanCode(bw, codes, literal_ix); 450 } else if (PixOrCopyIsLiteral(v)) { 451 static const int order[] = { 1, 2, 0, 3 }; 452 int k; 453 for (k = 0; k < 4; ++k) { 454 const int code = PixOrCopyLiteral(v, order[k]); 455 WriteHuffmanCode(bw, codes + k, code); 456 } 457 } else { 458 int bits, n_bits; 459 int code, distance; 460 461 VP8LPrefixEncode(v->len, &code, &n_bits, &bits); 462 WriteHuffmanCode(bw, codes, 256 + code); 463 VP8LWriteBits(bw, n_bits, bits); 464 465 distance = PixOrCopyDistance(v); 466 VP8LPrefixEncode(distance, &code, &n_bits, &bits); 467 WriteHuffmanCode(bw, codes + 4, code); 468 VP8LWriteBits(bw, n_bits, bits); 469 } 470 x += PixOrCopyLength(v); 471 while (x >= width) { 472 x -= width; 473 ++y; 474 } 475 VP8LRefsCursorNext(&c); 476 } 477 return bw->error_ ? VP8_ENC_ERROR_OUT_OF_MEMORY : VP8_ENC_OK; 478} 479 480// Special case of EncodeImageInternal() for cache-bits=0, histo_bits=31 481static WebPEncodingError EncodeImageNoHuffman(VP8LBitWriter* const bw, 482 const uint32_t* const argb, 483 VP8LHashChain* const hash_chain, 484 VP8LBackwardRefs refs_array[2], 485 int width, int height, 486 int quality) { 487 int i; 488 int max_tokens = 0; 489 WebPEncodingError err = VP8_ENC_OK; 490 VP8LBackwardRefs* refs; 491 HuffmanTreeToken* tokens = NULL; 492 HuffmanTreeCode huffman_codes[5] = { { 0, NULL, NULL } }; 493 const uint16_t histogram_symbols[1] = { 0 }; // only one tree, one symbol 494 VP8LHistogramSet* const histogram_image = VP8LAllocateHistogramSet(1, 0); 495 HuffmanTree* const huff_tree = (HuffmanTree*)WebPSafeMalloc( 496 3ULL * CODE_LENGTH_CODES, sizeof(*huff_tree)); 497 if (histogram_image == NULL || huff_tree == NULL) { 498 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 499 goto Error; 500 } 501 502 // Calculate backward references from ARGB image. 503 refs = VP8LGetBackwardReferences(width, height, argb, quality, 0, 1, 504 hash_chain, refs_array); 505 if (refs == NULL) { 506 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 507 goto Error; 508 } 509 // Build histogram image and symbols from backward references. 510 VP8LHistogramStoreRefs(refs, histogram_image->histograms[0]); 511 512 // Create Huffman bit lengths and codes for each histogram image. 513 assert(histogram_image->size == 1); 514 if (!GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) { 515 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 516 goto Error; 517 } 518 519 // No color cache, no Huffman image. 520 VP8LWriteBits(bw, 1, 0); 521 522 // Find maximum number of symbols for the huffman tree-set. 523 for (i = 0; i < 5; ++i) { 524 HuffmanTreeCode* const codes = &huffman_codes[i]; 525 if (max_tokens < codes->num_symbols) { 526 max_tokens = codes->num_symbols; 527 } 528 } 529 530 tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, sizeof(*tokens)); 531 if (tokens == NULL) { 532 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 533 goto Error; 534 } 535 536 // Store Huffman codes. 537 for (i = 0; i < 5; ++i) { 538 HuffmanTreeCode* const codes = &huffman_codes[i]; 539 StoreHuffmanCode(bw, huff_tree, tokens, codes); 540 ClearHuffmanTreeIfOnlyOneSymbol(codes); 541 } 542 543 // Store actual literals. 544 err = StoreImageToBitMask(bw, width, 0, refs, histogram_symbols, 545 huffman_codes); 546 547 Error: 548 WebPSafeFree(tokens); 549 WebPSafeFree(huff_tree); 550 VP8LFreeHistogramSet(histogram_image); 551 WebPSafeFree(huffman_codes[0].codes); 552 return err; 553} 554 555static WebPEncodingError EncodeImageInternal(VP8LBitWriter* const bw, 556 const uint32_t* const argb, 557 VP8LHashChain* const hash_chain, 558 VP8LBackwardRefs refs_array[2], 559 int width, int height, int quality, 560 int cache_bits, 561 int histogram_bits) { 562 WebPEncodingError err = VP8_ENC_OK; 563 const int use_2d_locality = 1; 564 const int use_color_cache = (cache_bits > 0); 565 const uint32_t histogram_image_xysize = 566 VP8LSubSampleSize(width, histogram_bits) * 567 VP8LSubSampleSize(height, histogram_bits); 568 VP8LHistogramSet* histogram_image = 569 VP8LAllocateHistogramSet(histogram_image_xysize, cache_bits); 570 int histogram_image_size = 0; 571 size_t bit_array_size = 0; 572 HuffmanTree* huff_tree = NULL; 573 HuffmanTreeToken* tokens = NULL; 574 HuffmanTreeCode* huffman_codes = NULL; 575 VP8LBackwardRefs refs; 576 VP8LBackwardRefs* best_refs; 577 uint16_t* const histogram_symbols = 578 (uint16_t*)WebPSafeMalloc(histogram_image_xysize, 579 sizeof(*histogram_symbols)); 580 assert(histogram_bits >= MIN_HUFFMAN_BITS); 581 assert(histogram_bits <= MAX_HUFFMAN_BITS); 582 583 VP8LBackwardRefsInit(&refs, refs_array[0].block_size_); 584 if (histogram_image == NULL || histogram_symbols == NULL) { 585 VP8LFreeHistogramSet(histogram_image); 586 WebPSafeFree(histogram_symbols); 587 return 0; 588 } 589 590 // 'best_refs' is the reference to the best backward refs and points to one 591 // of refs_array[0] or refs_array[1]. 592 // Calculate backward references from ARGB image. 593 best_refs = VP8LGetBackwardReferences(width, height, argb, quality, 594 cache_bits, use_2d_locality, 595 hash_chain, refs_array); 596 if (best_refs == NULL || !VP8LBackwardRefsCopy(best_refs, &refs)) { 597 goto Error; 598 } 599 // Build histogram image and symbols from backward references. 600 if (!VP8LGetHistoImageSymbols(width, height, &refs, 601 quality, histogram_bits, cache_bits, 602 histogram_image, 603 histogram_symbols)) { 604 goto Error; 605 } 606 // Create Huffman bit lengths and codes for each histogram image. 607 histogram_image_size = histogram_image->size; 608 bit_array_size = 5 * histogram_image_size; 609 huffman_codes = (HuffmanTreeCode*)WebPSafeCalloc(bit_array_size, 610 sizeof(*huffman_codes)); 611 if (huffman_codes == NULL || 612 !GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) { 613 goto Error; 614 } 615 // Free combined histograms. 616 VP8LFreeHistogramSet(histogram_image); 617 histogram_image = NULL; 618 619 // Color Cache parameters. 620 VP8LWriteBits(bw, 1, use_color_cache); 621 if (use_color_cache) { 622 VP8LWriteBits(bw, 4, cache_bits); 623 } 624 625 // Huffman image + meta huffman. 626 { 627 const int write_histogram_image = (histogram_image_size > 1); 628 VP8LWriteBits(bw, 1, write_histogram_image); 629 if (write_histogram_image) { 630 uint32_t* const histogram_argb = 631 (uint32_t*)WebPSafeMalloc(histogram_image_xysize, 632 sizeof(*histogram_argb)); 633 int max_index = 0; 634 uint32_t i; 635 if (histogram_argb == NULL) goto Error; 636 for (i = 0; i < histogram_image_xysize; ++i) { 637 const int symbol_index = histogram_symbols[i] & 0xffff; 638 histogram_argb[i] = 0xff000000 | (symbol_index << 8); 639 if (symbol_index >= max_index) { 640 max_index = symbol_index + 1; 641 } 642 } 643 histogram_image_size = max_index; 644 645 VP8LWriteBits(bw, 3, histogram_bits - 2); 646 err = EncodeImageNoHuffman(bw, histogram_argb, hash_chain, refs_array, 647 VP8LSubSampleSize(width, histogram_bits), 648 VP8LSubSampleSize(height, histogram_bits), 649 quality); 650 WebPSafeFree(histogram_argb); 651 if (err != VP8_ENC_OK) goto Error; 652 } 653 } 654 655 // Store Huffman codes. 656 { 657 int i; 658 int max_tokens = 0; 659 huff_tree = (HuffmanTree*)WebPSafeMalloc(3ULL * CODE_LENGTH_CODES, 660 sizeof(*huff_tree)); 661 if (huff_tree == NULL) goto Error; 662 // Find maximum number of symbols for the huffman tree-set. 663 for (i = 0; i < 5 * histogram_image_size; ++i) { 664 HuffmanTreeCode* const codes = &huffman_codes[i]; 665 if (max_tokens < codes->num_symbols) { 666 max_tokens = codes->num_symbols; 667 } 668 } 669 tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, 670 sizeof(*tokens)); 671 if (tokens == NULL) goto Error; 672 for (i = 0; i < 5 * histogram_image_size; ++i) { 673 HuffmanTreeCode* const codes = &huffman_codes[i]; 674 StoreHuffmanCode(bw, huff_tree, tokens, codes); 675 ClearHuffmanTreeIfOnlyOneSymbol(codes); 676 } 677 } 678 679 // Store actual literals. 680 err = StoreImageToBitMask(bw, width, histogram_bits, &refs, 681 histogram_symbols, huffman_codes); 682 683 Error: 684 WebPSafeFree(tokens); 685 WebPSafeFree(huff_tree); 686 VP8LFreeHistogramSet(histogram_image); 687 VP8LBackwardRefsClear(&refs); 688 if (huffman_codes != NULL) { 689 WebPSafeFree(huffman_codes->codes); 690 WebPSafeFree(huffman_codes); 691 } 692 WebPSafeFree(histogram_symbols); 693 return err; 694} 695 696// ----------------------------------------------------------------------------- 697// Transforms 698 699// Check if it would be a good idea to subtract green from red and blue. We 700// only impact entropy in red/blue components, don't bother to look at others. 701static WebPEncodingError EvalAndApplySubtractGreen(VP8LEncoder* const enc, 702 int width, int height, 703 VP8LBitWriter* const bw) { 704 if (!enc->use_palette_) { 705 int i; 706 const uint32_t* const argb = enc->argb_; 707 double bit_cost_before, bit_cost_after; 708 // Allocate histogram with cache_bits = 1. 709 VP8LHistogram* const histo = VP8LAllocateHistogram(1); 710 if (histo == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY; 711 for (i = 0; i < width * height; ++i) { 712 const uint32_t c = argb[i]; 713 ++histo->red_[(c >> 16) & 0xff]; 714 ++histo->blue_[(c >> 0) & 0xff]; 715 } 716 bit_cost_before = VP8LHistogramEstimateBits(histo); 717 718 VP8LHistogramInit(histo, 1); 719 for (i = 0; i < width * height; ++i) { 720 const uint32_t c = argb[i]; 721 const int green = (c >> 8) & 0xff; 722 ++histo->red_[((c >> 16) - green) & 0xff]; 723 ++histo->blue_[((c >> 0) - green) & 0xff]; 724 } 725 bit_cost_after = VP8LHistogramEstimateBits(histo); 726 VP8LFreeHistogram(histo); 727 728 // Check if subtracting green yields low entropy. 729 enc->use_subtract_green_ = (bit_cost_after < bit_cost_before); 730 if (enc->use_subtract_green_) { 731 VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); 732 VP8LWriteBits(bw, 2, SUBTRACT_GREEN); 733 VP8LSubtractGreenFromBlueAndRed(enc->argb_, width * height); 734 } 735 } 736 return VP8_ENC_OK; 737} 738 739static WebPEncodingError ApplyPredictFilter(const VP8LEncoder* const enc, 740 int width, int height, int quality, 741 VP8LBitWriter* const bw) { 742 const int pred_bits = enc->transform_bits_; 743 const int transform_width = VP8LSubSampleSize(width, pred_bits); 744 const int transform_height = VP8LSubSampleSize(height, pred_bits); 745 746 VP8LResidualImage(width, height, pred_bits, enc->argb_, enc->argb_scratch_, 747 enc->transform_data_); 748 VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); 749 VP8LWriteBits(bw, 2, PREDICTOR_TRANSFORM); 750 assert(pred_bits >= 2); 751 VP8LWriteBits(bw, 3, pred_bits - 2); 752 return EncodeImageNoHuffman(bw, enc->transform_data_, 753 (VP8LHashChain*)&enc->hash_chain_, 754 (VP8LBackwardRefs*)enc->refs_, // cast const away 755 transform_width, transform_height, 756 quality); 757} 758 759static WebPEncodingError ApplyCrossColorFilter(const VP8LEncoder* const enc, 760 int width, int height, 761 int quality, 762 VP8LBitWriter* const bw) { 763 const int ccolor_transform_bits = enc->transform_bits_; 764 const int transform_width = VP8LSubSampleSize(width, ccolor_transform_bits); 765 const int transform_height = VP8LSubSampleSize(height, ccolor_transform_bits); 766 767 VP8LColorSpaceTransform(width, height, ccolor_transform_bits, quality, 768 enc->argb_, enc->transform_data_); 769 VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); 770 VP8LWriteBits(bw, 2, CROSS_COLOR_TRANSFORM); 771 assert(ccolor_transform_bits >= 2); 772 VP8LWriteBits(bw, 3, ccolor_transform_bits - 2); 773 return EncodeImageNoHuffman(bw, enc->transform_data_, 774 (VP8LHashChain*)&enc->hash_chain_, 775 (VP8LBackwardRefs*)enc->refs_, // cast const away 776 transform_width, transform_height, 777 quality); 778} 779 780// ----------------------------------------------------------------------------- 781 782static WebPEncodingError WriteRiffHeader(const WebPPicture* const pic, 783 size_t riff_size, size_t vp8l_size) { 784 uint8_t riff[RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE + VP8L_SIGNATURE_SIZE] = { 785 'R', 'I', 'F', 'F', 0, 0, 0, 0, 'W', 'E', 'B', 'P', 786 'V', 'P', '8', 'L', 0, 0, 0, 0, VP8L_MAGIC_BYTE, 787 }; 788 PutLE32(riff + TAG_SIZE, (uint32_t)riff_size); 789 PutLE32(riff + RIFF_HEADER_SIZE + TAG_SIZE, (uint32_t)vp8l_size); 790 if (!pic->writer(riff, sizeof(riff), pic)) { 791 return VP8_ENC_ERROR_BAD_WRITE; 792 } 793 return VP8_ENC_OK; 794} 795 796static int WriteImageSize(const WebPPicture* const pic, 797 VP8LBitWriter* const bw) { 798 const int width = pic->width - 1; 799 const int height = pic->height - 1; 800 assert(width < WEBP_MAX_DIMENSION && height < WEBP_MAX_DIMENSION); 801 802 VP8LWriteBits(bw, VP8L_IMAGE_SIZE_BITS, width); 803 VP8LWriteBits(bw, VP8L_IMAGE_SIZE_BITS, height); 804 return !bw->error_; 805} 806 807static int WriteRealAlphaAndVersion(VP8LBitWriter* const bw, int has_alpha) { 808 VP8LWriteBits(bw, 1, has_alpha); 809 VP8LWriteBits(bw, VP8L_VERSION_BITS, VP8L_VERSION); 810 return !bw->error_; 811} 812 813static WebPEncodingError WriteImage(const WebPPicture* const pic, 814 VP8LBitWriter* const bw, 815 size_t* const coded_size) { 816 WebPEncodingError err = VP8_ENC_OK; 817 const uint8_t* const webpll_data = VP8LBitWriterFinish(bw); 818 const size_t webpll_size = VP8LBitWriterNumBytes(bw); 819 const size_t vp8l_size = VP8L_SIGNATURE_SIZE + webpll_size; 820 const size_t pad = vp8l_size & 1; 821 const size_t riff_size = TAG_SIZE + CHUNK_HEADER_SIZE + vp8l_size + pad; 822 823 err = WriteRiffHeader(pic, riff_size, vp8l_size); 824 if (err != VP8_ENC_OK) goto Error; 825 826 if (!pic->writer(webpll_data, webpll_size, pic)) { 827 err = VP8_ENC_ERROR_BAD_WRITE; 828 goto Error; 829 } 830 831 if (pad) { 832 const uint8_t pad_byte[1] = { 0 }; 833 if (!pic->writer(pad_byte, 1, pic)) { 834 err = VP8_ENC_ERROR_BAD_WRITE; 835 goto Error; 836 } 837 } 838 *coded_size = CHUNK_HEADER_SIZE + riff_size; 839 return VP8_ENC_OK; 840 841 Error: 842 return err; 843} 844 845// ----------------------------------------------------------------------------- 846 847// Allocates the memory for argb (W x H) buffer, 2 rows of context for 848// prediction and transform data. 849static WebPEncodingError AllocateTransformBuffer(VP8LEncoder* const enc, 850 int width, int height) { 851 WebPEncodingError err = VP8_ENC_OK; 852 const int tile_size = 1 << enc->transform_bits_; 853 const uint64_t image_size = width * height; 854 const uint64_t argb_scratch_size = tile_size * width + width; 855 const int transform_data_size = 856 VP8LSubSampleSize(width, enc->transform_bits_) * 857 VP8LSubSampleSize(height, enc->transform_bits_); 858 const uint64_t total_size = 859 image_size + argb_scratch_size + (uint64_t)transform_data_size; 860 uint32_t* mem = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*mem)); 861 if (mem == NULL) { 862 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 863 goto Error; 864 } 865 enc->argb_ = mem; 866 mem += image_size; 867 enc->argb_scratch_ = mem; 868 mem += argb_scratch_size; 869 enc->transform_data_ = mem; 870 enc->current_width_ = width; 871 872 Error: 873 return err; 874} 875 876static void ApplyPalette(uint32_t* src, uint32_t* dst, 877 uint32_t src_stride, uint32_t dst_stride, 878 const uint32_t* palette, int palette_size, 879 int width, int height, int xbits, uint8_t* row) { 880 int i, x, y; 881 int use_LUT = 1; 882 for (i = 0; i < palette_size; ++i) { 883 if ((palette[i] & 0xffff00ffu) != 0) { 884 use_LUT = 0; 885 break; 886 } 887 } 888 889 if (use_LUT) { 890 uint8_t inv_palette[MAX_PALETTE_SIZE] = { 0 }; 891 for (i = 0; i < palette_size; ++i) { 892 const int color = (palette[i] >> 8) & 0xff; 893 inv_palette[color] = i; 894 } 895 for (y = 0; y < height; ++y) { 896 for (x = 0; x < width; ++x) { 897 const int color = (src[x] >> 8) & 0xff; 898 row[x] = inv_palette[color]; 899 } 900 VP8LBundleColorMap(row, width, xbits, dst); 901 src += src_stride; 902 dst += dst_stride; 903 } 904 } else { 905 // Use 1 pixel cache for ARGB pixels. 906 uint32_t last_pix = palette[0]; 907 int last_idx = 0; 908 for (y = 0; y < height; ++y) { 909 for (x = 0; x < width; ++x) { 910 const uint32_t pix = src[x]; 911 if (pix != last_pix) { 912 for (i = 0; i < palette_size; ++i) { 913 if (pix == palette[i]) { 914 last_idx = i; 915 last_pix = pix; 916 break; 917 } 918 } 919 } 920 row[x] = last_idx; 921 } 922 VP8LBundleColorMap(row, width, xbits, dst); 923 src += src_stride; 924 dst += dst_stride; 925 } 926 } 927} 928 929// Note: Expects "enc->palette_" to be set properly. 930// Also, "enc->palette_" will be modified after this call and should not be used 931// later. 932static WebPEncodingError EncodePalette(VP8LBitWriter* const bw, 933 VP8LEncoder* const enc, int quality) { 934 WebPEncodingError err = VP8_ENC_OK; 935 int i; 936 const WebPPicture* const pic = enc->pic_; 937 uint32_t* src = pic->argb; 938 uint32_t* dst; 939 const int width = pic->width; 940 const int height = pic->height; 941 uint32_t* const palette = enc->palette_; 942 const int palette_size = enc->palette_size_; 943 uint8_t* row = NULL; 944 int xbits; 945 946 // Replace each input pixel by corresponding palette index. 947 // This is done line by line. 948 if (palette_size <= 4) { 949 xbits = (palette_size <= 2) ? 3 : 2; 950 } else { 951 xbits = (palette_size <= 16) ? 1 : 0; 952 } 953 954 err = AllocateTransformBuffer(enc, VP8LSubSampleSize(width, xbits), height); 955 if (err != VP8_ENC_OK) goto Error; 956 dst = enc->argb_; 957 958 row = (uint8_t*)WebPSafeMalloc(width, sizeof(*row)); 959 if (row == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY; 960 961 ApplyPalette(src, dst, pic->argb_stride, enc->current_width_, 962 palette, palette_size, width, height, xbits, row); 963 964 // Save palette to bitstream. 965 VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); 966 VP8LWriteBits(bw, 2, COLOR_INDEXING_TRANSFORM); 967 assert(palette_size >= 1); 968 VP8LWriteBits(bw, 8, palette_size - 1); 969 for (i = palette_size - 1; i >= 1; --i) { 970 palette[i] = VP8LSubPixels(palette[i], palette[i - 1]); 971 } 972 err = EncodeImageNoHuffman(bw, palette, &enc->hash_chain_, enc->refs_, 973 palette_size, 1, quality); 974 975 Error: 976 WebPSafeFree(row); 977 return err; 978} 979 980// ----------------------------------------------------------------------------- 981 982static int GetHistoBits(int method, int use_palette, int width, int height) { 983 const int hist_size = VP8LGetHistogramSize(MAX_COLOR_CACHE_BITS); 984 // Make tile size a function of encoding method (Range: 0 to 6). 985 int histo_bits = (use_palette ? 9 : 7) - method; 986 while (1) { 987 const int huff_image_size = VP8LSubSampleSize(width, histo_bits) * 988 VP8LSubSampleSize(height, histo_bits); 989 if ((uint64_t)huff_image_size * hist_size <= MAX_HUFF_IMAGE_SIZE) break; 990 ++histo_bits; 991 } 992 return (histo_bits < MIN_HUFFMAN_BITS) ? MIN_HUFFMAN_BITS : 993 (histo_bits > MAX_HUFFMAN_BITS) ? MAX_HUFFMAN_BITS : histo_bits; 994} 995 996static int GetTransformBits(int method, int histo_bits) { 997 const int max_transform_bits = (method < 4) ? 6 : (method > 4) ? 4 : 5; 998 return (histo_bits > max_transform_bits) ? max_transform_bits : histo_bits; 999} 1000 1001static int GetCacheBits(float quality) { 1002 return (quality <= 25.f) ? 0 : 7; 1003} 1004 1005static void FinishEncParams(VP8LEncoder* const enc) { 1006 const WebPConfig* const config = enc->config_; 1007 const WebPPicture* const pic = enc->pic_; 1008 const int method = config->method; 1009 const float quality = config->quality; 1010 const int use_palette = enc->use_palette_; 1011 enc->histo_bits_ = GetHistoBits(method, use_palette, pic->width, pic->height); 1012 enc->transform_bits_ = GetTransformBits(method, enc->histo_bits_); 1013 enc->cache_bits_ = GetCacheBits(quality); 1014} 1015 1016// ----------------------------------------------------------------------------- 1017// VP8LEncoder 1018 1019static VP8LEncoder* VP8LEncoderNew(const WebPConfig* const config, 1020 const WebPPicture* const picture) { 1021 VP8LEncoder* const enc = (VP8LEncoder*)WebPSafeCalloc(1ULL, sizeof(*enc)); 1022 if (enc == NULL) { 1023 WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY); 1024 return NULL; 1025 } 1026 enc->config_ = config; 1027 enc->pic_ = picture; 1028 1029 VP8LDspInit(); 1030 1031 return enc; 1032} 1033 1034static void VP8LEncoderDelete(VP8LEncoder* enc) { 1035 if (enc != NULL) { 1036 VP8LHashChainClear(&enc->hash_chain_); 1037 VP8LBackwardRefsClear(&enc->refs_[0]); 1038 VP8LBackwardRefsClear(&enc->refs_[1]); 1039 WebPSafeFree(enc->argb_); 1040 WebPSafeFree(enc); 1041 } 1042} 1043 1044// ----------------------------------------------------------------------------- 1045// Main call 1046 1047WebPEncodingError VP8LEncodeStream(const WebPConfig* const config, 1048 const WebPPicture* const picture, 1049 VP8LBitWriter* const bw) { 1050 WebPEncodingError err = VP8_ENC_OK; 1051 const int quality = (int)config->quality; 1052 const int width = picture->width; 1053 const int height = picture->height; 1054 VP8LEncoder* const enc = VP8LEncoderNew(config, picture); 1055 const size_t byte_position = VP8LBitWriterNumBytes(bw); 1056 1057 if (enc == NULL) { 1058 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1059 goto Error; 1060 } 1061 1062 // --------------------------------------------------------------------------- 1063 // Analyze image (entropy, num_palettes etc) 1064 1065 if (!AnalyzeAndInit(enc, config->image_hint)) { 1066 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1067 goto Error; 1068 } 1069 1070 FinishEncParams(enc); 1071 1072 if (enc->use_palette_) { 1073 err = EncodePalette(bw, enc, quality); 1074 if (err != VP8_ENC_OK) goto Error; 1075 // Color cache is disabled for palette. 1076 enc->cache_bits_ = 0; 1077 } 1078 1079 // In case image is not packed. 1080 if (enc->argb_ == NULL) { 1081 int y; 1082 err = AllocateTransformBuffer(enc, width, height); 1083 if (err != VP8_ENC_OK) goto Error; 1084 for (y = 0; y < height; ++y) { 1085 memcpy(enc->argb_ + y * width, 1086 picture->argb + y * picture->argb_stride, 1087 width * sizeof(*enc->argb_)); 1088 } 1089 enc->current_width_ = width; 1090 } 1091 1092 // --------------------------------------------------------------------------- 1093 // Apply transforms and write transform data. 1094 1095 err = EvalAndApplySubtractGreen(enc, enc->current_width_, height, bw); 1096 if (err != VP8_ENC_OK) goto Error; 1097 1098 if (enc->use_predict_) { 1099 err = ApplyPredictFilter(enc, enc->current_width_, height, quality, bw); 1100 if (err != VP8_ENC_OK) goto Error; 1101 } 1102 1103 if (enc->use_cross_color_) { 1104 err = ApplyCrossColorFilter(enc, enc->current_width_, height, quality, bw); 1105 if (err != VP8_ENC_OK) goto Error; 1106 } 1107 1108 VP8LWriteBits(bw, 1, !TRANSFORM_PRESENT); // No more transforms. 1109 1110 // --------------------------------------------------------------------------- 1111 // Estimate the color cache size. 1112 1113 if (enc->cache_bits_ > 0) { 1114 if (!VP8LCalculateEstimateForCacheSize(enc->argb_, enc->current_width_, 1115 height, quality, &enc->hash_chain_, 1116 &enc->refs_[0], &enc->cache_bits_)) { 1117 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1118 goto Error; 1119 } 1120 } 1121 1122 // --------------------------------------------------------------------------- 1123 // Encode and write the transformed image. 1124 1125 err = EncodeImageInternal(bw, enc->argb_, &enc->hash_chain_, enc->refs_, 1126 enc->current_width_, height, quality, 1127 enc->cache_bits_, enc->histo_bits_); 1128 if (err != VP8_ENC_OK) goto Error; 1129 1130 if (picture->stats != NULL) { 1131 WebPAuxStats* const stats = picture->stats; 1132 stats->lossless_features = 0; 1133 if (enc->use_predict_) stats->lossless_features |= 1; 1134 if (enc->use_cross_color_) stats->lossless_features |= 2; 1135 if (enc->use_subtract_green_) stats->lossless_features |= 4; 1136 if (enc->use_palette_) stats->lossless_features |= 8; 1137 stats->histogram_bits = enc->histo_bits_; 1138 stats->transform_bits = enc->transform_bits_; 1139 stats->cache_bits = enc->cache_bits_; 1140 stats->palette_size = enc->palette_size_; 1141 stats->lossless_size = (int)(VP8LBitWriterNumBytes(bw) - byte_position); 1142 } 1143 1144 Error: 1145 VP8LEncoderDelete(enc); 1146 return err; 1147} 1148 1149int VP8LEncodeImage(const WebPConfig* const config, 1150 const WebPPicture* const picture) { 1151 int width, height; 1152 int has_alpha; 1153 size_t coded_size; 1154 int percent = 0; 1155 int initial_size; 1156 WebPEncodingError err = VP8_ENC_OK; 1157 VP8LBitWriter bw; 1158 1159 if (picture == NULL) return 0; 1160 1161 if (config == NULL || picture->argb == NULL) { 1162 err = VP8_ENC_ERROR_NULL_PARAMETER; 1163 WebPEncodingSetError(picture, err); 1164 return 0; 1165 } 1166 1167 width = picture->width; 1168 height = picture->height; 1169 // Initialize BitWriter with size corresponding to 16 bpp to photo images and 1170 // 8 bpp for graphical images. 1171 initial_size = (config->image_hint == WEBP_HINT_GRAPH) ? 1172 width * height : width * height * 2; 1173 if (!VP8LBitWriterInit(&bw, initial_size)) { 1174 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1175 goto Error; 1176 } 1177 1178 if (!WebPReportProgress(picture, 1, &percent)) { 1179 UserAbort: 1180 err = VP8_ENC_ERROR_USER_ABORT; 1181 goto Error; 1182 } 1183 // Reset stats (for pure lossless coding) 1184 if (picture->stats != NULL) { 1185 WebPAuxStats* const stats = picture->stats; 1186 memset(stats, 0, sizeof(*stats)); 1187 stats->PSNR[0] = 99.f; 1188 stats->PSNR[1] = 99.f; 1189 stats->PSNR[2] = 99.f; 1190 stats->PSNR[3] = 99.f; 1191 stats->PSNR[4] = 99.f; 1192 } 1193 1194 // Write image size. 1195 if (!WriteImageSize(picture, &bw)) { 1196 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1197 goto Error; 1198 } 1199 1200 has_alpha = WebPPictureHasTransparency(picture); 1201 // Write the non-trivial Alpha flag and lossless version. 1202 if (!WriteRealAlphaAndVersion(&bw, has_alpha)) { 1203 err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1204 goto Error; 1205 } 1206 1207 if (!WebPReportProgress(picture, 5, &percent)) goto UserAbort; 1208 1209 // Encode main image stream. 1210 err = VP8LEncodeStream(config, picture, &bw); 1211 if (err != VP8_ENC_OK) goto Error; 1212 1213 // TODO(skal): have a fine-grained progress report in VP8LEncodeStream(). 1214 if (!WebPReportProgress(picture, 90, &percent)) goto UserAbort; 1215 1216 // Finish the RIFF chunk. 1217 err = WriteImage(picture, &bw, &coded_size); 1218 if (err != VP8_ENC_OK) goto Error; 1219 1220 if (!WebPReportProgress(picture, 100, &percent)) goto UserAbort; 1221 1222 // Save size. 1223 if (picture->stats != NULL) { 1224 picture->stats->coded_size += (int)coded_size; 1225 picture->stats->lossless_size = (int)coded_size; 1226 } 1227 1228 if (picture->extra_info != NULL) { 1229 const int mb_w = (width + 15) >> 4; 1230 const int mb_h = (height + 15) >> 4; 1231 memset(picture->extra_info, 0, mb_w * mb_h * sizeof(*picture->extra_info)); 1232 } 1233 1234 Error: 1235 if (bw.error_) err = VP8_ENC_ERROR_OUT_OF_MEMORY; 1236 VP8LBitWriterDestroy(&bw); 1237 if (err != VP8_ENC_OK) { 1238 WebPEncodingSetError(picture, err); 1239 return 0; 1240 } 1241 return 1; 1242} 1243 1244//------------------------------------------------------------------------------ 1245