// Copyright 2012 Google Inc. All Rights Reserved. // // Use of this source code is governed by a BSD-style license // that can be found in the COPYING file in the root of the source // tree. An additional intellectual property rights grant can be found // in the file PATENTS. All contributing project authors may // be found in the AUTHORS file in the root of the source tree. // ----------------------------------------------------------------------------- // // main entry for the lossless encoder. // // Author: Vikas Arora (vikaas.arora@gmail.com) // #include #include #include "./backward_references.h" #include "./histogram.h" #include "./vp8enci.h" #include "./vp8li.h" #include "../dsp/lossless.h" #include "../utils/bit_writer.h" #include "../utils/huffman_encode.h" #include "../utils/utils.h" #include "webp/format_constants.h" #include "./delta_palettization.h" #define PALETTE_KEY_RIGHT_SHIFT 22 // Key for 1K buffer. // Maximum number of histogram images (sub-blocks). #define MAX_HUFF_IMAGE_SIZE 2600 // Palette reordering for smaller sum of deltas (and for smaller storage). static int PaletteCompareColorsForQsort(const void* p1, const void* p2) { const uint32_t a = WebPMemToUint32(p1); const uint32_t b = WebPMemToUint32(p2); assert(a != b); return (a < b) ? -1 : 1; } static WEBP_INLINE uint32_t PaletteComponentDistance(uint32_t v) { return (v <= 128) ? v : (256 - v); } // Computes a value that is related to the entropy created by the // palette entry diff. // // Note that the last & 0xff is a no-operation in the next statement, but // removed by most compilers and is here only for regularity of the code. static WEBP_INLINE uint32_t PaletteColorDistance(uint32_t col1, uint32_t col2) { const uint32_t diff = VP8LSubPixels(col1, col2); const int kMoreWeightForRGBThanForAlpha = 9; uint32_t score; score = PaletteComponentDistance((diff >> 0) & 0xff); score += PaletteComponentDistance((diff >> 8) & 0xff); score += PaletteComponentDistance((diff >> 16) & 0xff); score *= kMoreWeightForRGBThanForAlpha; score += PaletteComponentDistance((diff >> 24) & 0xff); return score; } static WEBP_INLINE void SwapColor(uint32_t* const col1, uint32_t* const col2) { const uint32_t tmp = *col1; *col1 = *col2; *col2 = tmp; } static void GreedyMinimizeDeltas(uint32_t palette[], int num_colors) { // Find greedily always the closest color of the predicted color to minimize // deltas in the palette. This reduces storage needs since the // palette is stored with delta encoding. uint32_t predict = 0x00000000; int i, k; for (i = 0; i < num_colors; ++i) { int best_ix = i; uint32_t best_score = ~0U; for (k = i; k < num_colors; ++k) { const uint32_t cur_score = PaletteColorDistance(palette[k], predict); if (best_score > cur_score) { best_score = cur_score; best_ix = k; } } SwapColor(&palette[best_ix], &palette[i]); predict = palette[i]; } } // The palette has been sorted by alpha. This function checks if the other // components of the palette have a monotonic development with regards to // position in the palette. If all have monotonic development, there is // no benefit to re-organize them greedily. A monotonic development // would be spotted in green-only situations (like lossy alpha) or gray-scale // images. static int PaletteHasNonMonotonousDeltas(uint32_t palette[], int num_colors) { uint32_t predict = 0x000000; int i; uint8_t sign_found = 0x00; for (i = 0; i < num_colors; ++i) { const uint32_t diff = VP8LSubPixels(palette[i], predict); const uint8_t rd = (diff >> 16) & 0xff; const uint8_t gd = (diff >> 8) & 0xff; const uint8_t bd = (diff >> 0) & 0xff; if (rd != 0x00) { sign_found |= (rd < 0x80) ? 1 : 2; } if (gd != 0x00) { sign_found |= (gd < 0x80) ? 8 : 16; } if (bd != 0x00) { sign_found |= (bd < 0x80) ? 64 : 128; } predict = palette[i]; } return (sign_found & (sign_found << 1)) != 0; // two consequent signs. } // ----------------------------------------------------------------------------- // Palette // If number of colors in the image is less than or equal to MAX_PALETTE_SIZE, // creates a palette and returns true, else returns false. static int AnalyzeAndCreatePalette(const WebPPicture* const pic, int low_effort, uint32_t palette[MAX_PALETTE_SIZE], int* const palette_size) { const int num_colors = WebPGetColorPalette(pic, palette); if (num_colors > MAX_PALETTE_SIZE) return 0; *palette_size = num_colors; qsort(palette, num_colors, sizeof(*palette), PaletteCompareColorsForQsort); if (!low_effort && PaletteHasNonMonotonousDeltas(palette, num_colors)) { GreedyMinimizeDeltas(palette, num_colors); } return 1; } // These five modes are evaluated and their respective entropy is computed. typedef enum { kDirect = 0, kSpatial = 1, kSubGreen = 2, kSpatialSubGreen = 3, kPalette = 4, kNumEntropyIx = 5 } EntropyIx; typedef enum { kHistoAlpha = 0, kHistoAlphaPred, kHistoGreen, kHistoGreenPred, kHistoRed, kHistoRedPred, kHistoBlue, kHistoBluePred, kHistoRedSubGreen, kHistoRedPredSubGreen, kHistoBlueSubGreen, kHistoBluePredSubGreen, kHistoPalette, kHistoTotal // Must be last. } HistoIx; static void AddSingleSubGreen(uint32_t p, uint32_t* r, uint32_t* b) { const uint32_t green = p >> 8; // The upper bits are masked away later. ++r[((p >> 16) - green) & 0xff]; ++b[(p - green) & 0xff]; } static void AddSingle(uint32_t p, uint32_t* a, uint32_t* r, uint32_t* g, uint32_t* b) { ++a[p >> 24]; ++r[(p >> 16) & 0xff]; ++g[(p >> 8) & 0xff]; ++b[(p & 0xff)]; } static int AnalyzeEntropy(const uint32_t* argb, int width, int height, int argb_stride, int use_palette, EntropyIx* const min_entropy_ix, int* const red_and_blue_always_zero) { // Allocate histogram set with cache_bits = 0. uint32_t* const histo = (uint32_t*)WebPSafeCalloc(kHistoTotal, sizeof(*histo) * 256); if (histo != NULL) { int i, x, y; const uint32_t* prev_row = argb; const uint32_t* curr_row = argb + argb_stride; for (y = 1; y < height; ++y) { uint32_t prev_pix = curr_row[0]; for (x = 1; x < width; ++x) { const uint32_t pix = curr_row[x]; const uint32_t pix_diff = VP8LSubPixels(pix, prev_pix); if ((pix_diff == 0) || (pix == prev_row[x])) continue; prev_pix = pix; AddSingle(pix, &histo[kHistoAlpha * 256], &histo[kHistoRed * 256], &histo[kHistoGreen * 256], &histo[kHistoBlue * 256]); AddSingle(pix_diff, &histo[kHistoAlphaPred * 256], &histo[kHistoRedPred * 256], &histo[kHistoGreenPred * 256], &histo[kHistoBluePred * 256]); AddSingleSubGreen(pix, &histo[kHistoRedSubGreen * 256], &histo[kHistoBlueSubGreen * 256]); AddSingleSubGreen(pix_diff, &histo[kHistoRedPredSubGreen * 256], &histo[kHistoBluePredSubGreen * 256]); { // Approximate the palette by the entropy of the multiplicative hash. const int hash = ((pix + (pix >> 19)) * 0x39c5fba7) >> 24; ++histo[kHistoPalette * 256 + (hash & 0xff)]; } } prev_row = curr_row; curr_row += argb_stride; } { double entropy_comp[kHistoTotal]; double entropy[kNumEntropyIx]; EntropyIx k; EntropyIx last_mode_to_analyze = use_palette ? kPalette : kSpatialSubGreen; int j; // Let's add one zero to the predicted histograms. The zeros are removed // too efficiently by the pix_diff == 0 comparison, at least one of the // zeros is likely to exist. ++histo[kHistoRedPredSubGreen * 256]; ++histo[kHistoBluePredSubGreen * 256]; ++histo[kHistoRedPred * 256]; ++histo[kHistoGreenPred * 256]; ++histo[kHistoBluePred * 256]; ++histo[kHistoAlphaPred * 256]; for (j = 0; j < kHistoTotal; ++j) { entropy_comp[j] = VP8LBitsEntropy(&histo[j * 256], 256, NULL); } entropy[kDirect] = entropy_comp[kHistoAlpha] + entropy_comp[kHistoRed] + entropy_comp[kHistoGreen] + entropy_comp[kHistoBlue]; entropy[kSpatial] = entropy_comp[kHistoAlphaPred] + entropy_comp[kHistoRedPred] + entropy_comp[kHistoGreenPred] + entropy_comp[kHistoBluePred]; entropy[kSubGreen] = entropy_comp[kHistoAlpha] + entropy_comp[kHistoRedSubGreen] + entropy_comp[kHistoGreen] + entropy_comp[kHistoBlueSubGreen]; entropy[kSpatialSubGreen] = entropy_comp[kHistoAlphaPred] + entropy_comp[kHistoRedPredSubGreen] + entropy_comp[kHistoGreenPred] + entropy_comp[kHistoBluePredSubGreen]; // Palette mode seems more efficient in a breakeven case. Bias with 1.0. entropy[kPalette] = entropy_comp[kHistoPalette] - 1.0; *min_entropy_ix = kDirect; for (k = kDirect + 1; k <= last_mode_to_analyze; ++k) { if (entropy[*min_entropy_ix] > entropy[k]) { *min_entropy_ix = k; } } *red_and_blue_always_zero = 1; // Let's check if the histogram of the chosen entropy mode has // non-zero red and blue values. If all are zero, we can later skip // the cross color optimization. { static const uint8_t kHistoPairs[5][2] = { { kHistoRed, kHistoBlue }, { kHistoRedPred, kHistoBluePred }, { kHistoRedSubGreen, kHistoBlueSubGreen }, { kHistoRedPredSubGreen, kHistoBluePredSubGreen }, { kHistoRed, kHistoBlue } }; const uint32_t* const red_histo = &histo[256 * kHistoPairs[*min_entropy_ix][0]]; const uint32_t* const blue_histo = &histo[256 * kHistoPairs[*min_entropy_ix][1]]; for (i = 1; i < 256; ++i) { if ((red_histo[i] | blue_histo[i]) != 0) { *red_and_blue_always_zero = 0; break; } } } } WebPSafeFree(histo); return 1; } else { return 0; } } static int GetHistoBits(int method, int use_palette, int width, int height) { // Make tile size a function of encoding method (Range: 0 to 6). int histo_bits = (use_palette ? 9 : 7) - method; while (1) { const int huff_image_size = VP8LSubSampleSize(width, histo_bits) * VP8LSubSampleSize(height, histo_bits); if (huff_image_size <= MAX_HUFF_IMAGE_SIZE) break; ++histo_bits; } return (histo_bits < MIN_HUFFMAN_BITS) ? MIN_HUFFMAN_BITS : (histo_bits > MAX_HUFFMAN_BITS) ? MAX_HUFFMAN_BITS : histo_bits; } static int GetTransformBits(int method, int histo_bits) { const int max_transform_bits = (method < 4) ? 6 : (method > 4) ? 4 : 5; return (histo_bits > max_transform_bits) ? max_transform_bits : histo_bits; } static int AnalyzeAndInit(VP8LEncoder* const enc) { const WebPPicture* const pic = enc->pic_; const int width = pic->width; const int height = pic->height; const int pix_cnt = width * height; const WebPConfig* const config = enc->config_; const int method = config->method; const int low_effort = (config->method == 0); // we round the block size up, so we're guaranteed to have // at max MAX_REFS_BLOCK_PER_IMAGE blocks used: int refs_block_size = (pix_cnt - 1) / MAX_REFS_BLOCK_PER_IMAGE + 1; assert(pic != NULL && pic->argb != NULL); enc->use_cross_color_ = 0; enc->use_predict_ = 0; enc->use_subtract_green_ = 0; enc->use_palette_ = AnalyzeAndCreatePalette(pic, low_effort, enc->palette_, &enc->palette_size_); // TODO(jyrki): replace the decision to be based on an actual estimate // of entropy, or even spatial variance of entropy. enc->histo_bits_ = GetHistoBits(method, enc->use_palette_, pic->width, pic->height); enc->transform_bits_ = GetTransformBits(method, enc->histo_bits_); if (low_effort) { // AnalyzeEntropy is somewhat slow. enc->use_predict_ = !enc->use_palette_; enc->use_subtract_green_ = !enc->use_palette_; enc->use_cross_color_ = 0; } else { int red_and_blue_always_zero; EntropyIx min_entropy_ix; if (!AnalyzeEntropy(pic->argb, width, height, pic->argb_stride, enc->use_palette_, &min_entropy_ix, &red_and_blue_always_zero)) { return 0; } enc->use_palette_ = (min_entropy_ix == kPalette); enc->use_subtract_green_ = (min_entropy_ix == kSubGreen) || (min_entropy_ix == kSpatialSubGreen); enc->use_predict_ = (min_entropy_ix == kSpatial) || (min_entropy_ix == kSpatialSubGreen); enc->use_cross_color_ = red_and_blue_always_zero ? 0 : enc->use_predict_; } if (!VP8LHashChainInit(&enc->hash_chain_, pix_cnt)) return 0; // palette-friendly input typically uses less literals // -> reduce block size a bit if (enc->use_palette_) refs_block_size /= 2; VP8LBackwardRefsInit(&enc->refs_[0], refs_block_size); VP8LBackwardRefsInit(&enc->refs_[1], refs_block_size); return 1; } // Returns false in case of memory error. static int GetHuffBitLengthsAndCodes( const VP8LHistogramSet* const histogram_image, HuffmanTreeCode* const huffman_codes) { int i, k; int ok = 0; uint64_t total_length_size = 0; uint8_t* mem_buf = NULL; const int histogram_image_size = histogram_image->size; int max_num_symbols = 0; uint8_t* buf_rle = NULL; HuffmanTree* huff_tree = NULL; // Iterate over all histograms and get the aggregate number of codes used. for (i = 0; i < histogram_image_size; ++i) { const VP8LHistogram* const histo = histogram_image->histograms[i]; HuffmanTreeCode* const codes = &huffman_codes[5 * i]; for (k = 0; k < 5; ++k) { const int num_symbols = (k == 0) ? VP8LHistogramNumCodes(histo->palette_code_bits_) : (k == 4) ? NUM_DISTANCE_CODES : 256; codes[k].num_symbols = num_symbols; total_length_size += num_symbols; } } // Allocate and Set Huffman codes. { uint16_t* codes; uint8_t* lengths; mem_buf = (uint8_t*)WebPSafeCalloc(total_length_size, sizeof(*lengths) + sizeof(*codes)); if (mem_buf == NULL) goto End; codes = (uint16_t*)mem_buf; lengths = (uint8_t*)&codes[total_length_size]; for (i = 0; i < 5 * histogram_image_size; ++i) { const int bit_length = huffman_codes[i].num_symbols; huffman_codes[i].codes = codes; huffman_codes[i].code_lengths = lengths; codes += bit_length; lengths += bit_length; if (max_num_symbols < bit_length) { max_num_symbols = bit_length; } } } buf_rle = (uint8_t*)WebPSafeMalloc(1ULL, max_num_symbols); huff_tree = (HuffmanTree*)WebPSafeMalloc(3ULL * max_num_symbols, sizeof(*huff_tree)); if (buf_rle == NULL || huff_tree == NULL) goto End; // Create Huffman trees. for (i = 0; i < histogram_image_size; ++i) { HuffmanTreeCode* const codes = &huffman_codes[5 * i]; VP8LHistogram* const histo = histogram_image->histograms[i]; VP8LCreateHuffmanTree(histo->literal_, 15, buf_rle, huff_tree, codes + 0); VP8LCreateHuffmanTree(histo->red_, 15, buf_rle, huff_tree, codes + 1); VP8LCreateHuffmanTree(histo->blue_, 15, buf_rle, huff_tree, codes + 2); VP8LCreateHuffmanTree(histo->alpha_, 15, buf_rle, huff_tree, codes + 3); VP8LCreateHuffmanTree(histo->distance_, 15, buf_rle, huff_tree, codes + 4); } ok = 1; End: WebPSafeFree(huff_tree); WebPSafeFree(buf_rle); if (!ok) { WebPSafeFree(mem_buf); memset(huffman_codes, 0, 5 * histogram_image_size * sizeof(*huffman_codes)); } return ok; } static void StoreHuffmanTreeOfHuffmanTreeToBitMask( VP8LBitWriter* const bw, const uint8_t* code_length_bitdepth) { // RFC 1951 will calm you down if you are worried about this funny sequence. // This sequence is tuned from that, but more weighted for lower symbol count, // and more spiking histograms. static const uint8_t kStorageOrder[CODE_LENGTH_CODES] = { 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }; int i; // Throw away trailing zeros: int codes_to_store = CODE_LENGTH_CODES; for (; codes_to_store > 4; --codes_to_store) { if (code_length_bitdepth[kStorageOrder[codes_to_store - 1]] != 0) { break; } } VP8LPutBits(bw, codes_to_store - 4, 4); for (i = 0; i < codes_to_store; ++i) { VP8LPutBits(bw, code_length_bitdepth[kStorageOrder[i]], 3); } } static void ClearHuffmanTreeIfOnlyOneSymbol( HuffmanTreeCode* const huffman_code) { int k; int count = 0; for (k = 0; k < huffman_code->num_symbols; ++k) { if (huffman_code->code_lengths[k] != 0) { ++count; if (count > 1) return; } } for (k = 0; k < huffman_code->num_symbols; ++k) { huffman_code->code_lengths[k] = 0; huffman_code->codes[k] = 0; } } static void StoreHuffmanTreeToBitMask( VP8LBitWriter* const bw, const HuffmanTreeToken* const tokens, const int num_tokens, const HuffmanTreeCode* const huffman_code) { int i; for (i = 0; i < num_tokens; ++i) { const int ix = tokens[i].code; const int extra_bits = tokens[i].extra_bits; VP8LPutBits(bw, huffman_code->codes[ix], huffman_code->code_lengths[ix]); switch (ix) { case 16: VP8LPutBits(bw, extra_bits, 2); break; case 17: VP8LPutBits(bw, extra_bits, 3); break; case 18: VP8LPutBits(bw, extra_bits, 7); break; } } } // 'huff_tree' and 'tokens' are pre-alloacted buffers. static void StoreFullHuffmanCode(VP8LBitWriter* const bw, HuffmanTree* const huff_tree, HuffmanTreeToken* const tokens, const HuffmanTreeCode* const tree) { uint8_t code_length_bitdepth[CODE_LENGTH_CODES] = { 0 }; uint16_t code_length_bitdepth_symbols[CODE_LENGTH_CODES] = { 0 }; const int max_tokens = tree->num_symbols; int num_tokens; HuffmanTreeCode huffman_code; huffman_code.num_symbols = CODE_LENGTH_CODES; huffman_code.code_lengths = code_length_bitdepth; huffman_code.codes = code_length_bitdepth_symbols; VP8LPutBits(bw, 0, 1); num_tokens = VP8LCreateCompressedHuffmanTree(tree, tokens, max_tokens); { uint32_t histogram[CODE_LENGTH_CODES] = { 0 }; uint8_t buf_rle[CODE_LENGTH_CODES] = { 0 }; int i; for (i = 0; i < num_tokens; ++i) { ++histogram[tokens[i].code]; } VP8LCreateHuffmanTree(histogram, 7, buf_rle, huff_tree, &huffman_code); } StoreHuffmanTreeOfHuffmanTreeToBitMask(bw, code_length_bitdepth); ClearHuffmanTreeIfOnlyOneSymbol(&huffman_code); { int trailing_zero_bits = 0; int trimmed_length = num_tokens; int write_trimmed_length; int length; int i = num_tokens; while (i-- > 0) { const int ix = tokens[i].code; if (ix == 0 || ix == 17 || ix == 18) { --trimmed_length; // discount trailing zeros trailing_zero_bits += code_length_bitdepth[ix]; if (ix == 17) { trailing_zero_bits += 3; } else if (ix == 18) { trailing_zero_bits += 7; } } else { break; } } write_trimmed_length = (trimmed_length > 1 && trailing_zero_bits > 12); length = write_trimmed_length ? trimmed_length : num_tokens; VP8LPutBits(bw, write_trimmed_length, 1); if (write_trimmed_length) { const int nbits = VP8LBitsLog2Ceiling(trimmed_length - 1); const int nbitpairs = (nbits == 0) ? 1 : (nbits + 1) / 2; VP8LPutBits(bw, nbitpairs - 1, 3); assert(trimmed_length >= 2); VP8LPutBits(bw, trimmed_length - 2, nbitpairs * 2); } StoreHuffmanTreeToBitMask(bw, tokens, length, &huffman_code); } } // 'huff_tree' and 'tokens' are pre-alloacted buffers. static void StoreHuffmanCode(VP8LBitWriter* const bw, HuffmanTree* const huff_tree, HuffmanTreeToken* const tokens, const HuffmanTreeCode* const huffman_code) { int i; int count = 0; int symbols[2] = { 0, 0 }; const int kMaxBits = 8; const int kMaxSymbol = 1 << kMaxBits; // Check whether it's a small tree. for (i = 0; i < huffman_code->num_symbols && count < 3; ++i) { if (huffman_code->code_lengths[i] != 0) { if (count < 2) symbols[count] = i; ++count; } } if (count == 0) { // emit minimal tree for empty cases // bits: small tree marker: 1, count-1: 0, large 8-bit code: 0, code: 0 VP8LPutBits(bw, 0x01, 4); } else if (count <= 2 && symbols[0] < kMaxSymbol && symbols[1] < kMaxSymbol) { VP8LPutBits(bw, 1, 1); // Small tree marker to encode 1 or 2 symbols. VP8LPutBits(bw, count - 1, 1); if (symbols[0] <= 1) { VP8LPutBits(bw, 0, 1); // Code bit for small (1 bit) symbol value. VP8LPutBits(bw, symbols[0], 1); } else { VP8LPutBits(bw, 1, 1); VP8LPutBits(bw, symbols[0], 8); } if (count == 2) { VP8LPutBits(bw, symbols[1], 8); } } else { StoreFullHuffmanCode(bw, huff_tree, tokens, huffman_code); } } static WEBP_INLINE void WriteHuffmanCode(VP8LBitWriter* const bw, const HuffmanTreeCode* const code, int code_index) { const int depth = code->code_lengths[code_index]; const int symbol = code->codes[code_index]; VP8LPutBits(bw, symbol, depth); } static WEBP_INLINE void WriteHuffmanCodeWithExtraBits( VP8LBitWriter* const bw, const HuffmanTreeCode* const code, int code_index, int bits, int n_bits) { const int depth = code->code_lengths[code_index]; const int symbol = code->codes[code_index]; VP8LPutBits(bw, (bits << depth) | symbol, depth + n_bits); } static WebPEncodingError StoreImageToBitMask( VP8LBitWriter* const bw, int width, int histo_bits, VP8LBackwardRefs* const refs, const uint16_t* histogram_symbols, const HuffmanTreeCode* const huffman_codes) { const int histo_xsize = histo_bits ? VP8LSubSampleSize(width, histo_bits) : 1; const int tile_mask = (histo_bits == 0) ? 0 : -(1 << histo_bits); // x and y trace the position in the image. int x = 0; int y = 0; int tile_x = x & tile_mask; int tile_y = y & tile_mask; int histogram_ix = histogram_symbols[0]; const HuffmanTreeCode* codes = huffman_codes + 5 * histogram_ix; VP8LRefsCursor c = VP8LRefsCursorInit(refs); while (VP8LRefsCursorOk(&c)) { const PixOrCopy* const v = c.cur_pos; if ((tile_x != (x & tile_mask)) || (tile_y != (y & tile_mask))) { tile_x = x & tile_mask; tile_y = y & tile_mask; histogram_ix = histogram_symbols[(y >> histo_bits) * histo_xsize + (x >> histo_bits)]; codes = huffman_codes + 5 * histogram_ix; } if (PixOrCopyIsLiteral(v)) { static const int order[] = { 1, 2, 0, 3 }; int k; for (k = 0; k < 4; ++k) { const int code = PixOrCopyLiteral(v, order[k]); WriteHuffmanCode(bw, codes + k, code); } } else if (PixOrCopyIsCacheIdx(v)) { const int code = PixOrCopyCacheIdx(v); const int literal_ix = 256 + NUM_LENGTH_CODES + code; WriteHuffmanCode(bw, codes, literal_ix); } else { int bits, n_bits; int code; const int distance = PixOrCopyDistance(v); VP8LPrefixEncode(v->len, &code, &n_bits, &bits); WriteHuffmanCodeWithExtraBits(bw, codes, 256 + code, bits, n_bits); // Don't write the distance with the extra bits code since // the distance can be up to 18 bits of extra bits, and the prefix // 15 bits, totaling to 33, and our PutBits only supports up to 32 bits. // TODO(jyrki): optimize this further. VP8LPrefixEncode(distance, &code, &n_bits, &bits); WriteHuffmanCode(bw, codes + 4, code); VP8LPutBits(bw, bits, n_bits); } x += PixOrCopyLength(v); while (x >= width) { x -= width; ++y; } VP8LRefsCursorNext(&c); } return bw->error_ ? VP8_ENC_ERROR_OUT_OF_MEMORY : VP8_ENC_OK; } // Special case of EncodeImageInternal() for cache-bits=0, histo_bits=31 static WebPEncodingError EncodeImageNoHuffman(VP8LBitWriter* const bw, const uint32_t* const argb, VP8LHashChain* const hash_chain, VP8LBackwardRefs refs_array[2], int width, int height, int quality) { int i; int max_tokens = 0; WebPEncodingError err = VP8_ENC_OK; VP8LBackwardRefs* refs; HuffmanTreeToken* tokens = NULL; HuffmanTreeCode huffman_codes[5] = { { 0, NULL, NULL } }; const uint16_t histogram_symbols[1] = { 0 }; // only one tree, one symbol int cache_bits = 0; VP8LHistogramSet* histogram_image = NULL; HuffmanTree* const huff_tree = (HuffmanTree*)WebPSafeMalloc( 3ULL * CODE_LENGTH_CODES, sizeof(*huff_tree)); if (huff_tree == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Calculate backward references from ARGB image. if (VP8LHashChainFill(hash_chain, quality, argb, width, height) == 0) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } refs = VP8LGetBackwardReferences(width, height, argb, quality, 0, &cache_bits, hash_chain, refs_array); if (refs == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } histogram_image = VP8LAllocateHistogramSet(1, cache_bits); if (histogram_image == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Build histogram image and symbols from backward references. VP8LHistogramStoreRefs(refs, histogram_image->histograms[0]); // Create Huffman bit lengths and codes for each histogram image. assert(histogram_image->size == 1); if (!GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // No color cache, no Huffman image. VP8LPutBits(bw, 0, 1); // Find maximum number of symbols for the huffman tree-set. for (i = 0; i < 5; ++i) { HuffmanTreeCode* const codes = &huffman_codes[i]; if (max_tokens < codes->num_symbols) { max_tokens = codes->num_symbols; } } tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, sizeof(*tokens)); if (tokens == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Store Huffman codes. for (i = 0; i < 5; ++i) { HuffmanTreeCode* const codes = &huffman_codes[i]; StoreHuffmanCode(bw, huff_tree, tokens, codes); ClearHuffmanTreeIfOnlyOneSymbol(codes); } // Store actual literals. err = StoreImageToBitMask(bw, width, 0, refs, histogram_symbols, huffman_codes); Error: WebPSafeFree(tokens); WebPSafeFree(huff_tree); VP8LFreeHistogramSet(histogram_image); WebPSafeFree(huffman_codes[0].codes); return err; } static WebPEncodingError EncodeImageInternal(VP8LBitWriter* const bw, const uint32_t* const argb, VP8LHashChain* const hash_chain, VP8LBackwardRefs refs_array[2], int width, int height, int quality, int low_effort, int use_cache, int* cache_bits, int histogram_bits, size_t init_byte_position, int* const hdr_size, int* const data_size) { WebPEncodingError err = VP8_ENC_OK; const uint32_t histogram_image_xysize = VP8LSubSampleSize(width, histogram_bits) * VP8LSubSampleSize(height, histogram_bits); VP8LHistogramSet* histogram_image = NULL; VP8LHistogramSet* tmp_histos = NULL; int histogram_image_size = 0; size_t bit_array_size = 0; HuffmanTree* huff_tree = NULL; HuffmanTreeToken* tokens = NULL; HuffmanTreeCode* huffman_codes = NULL; VP8LBackwardRefs refs; VP8LBackwardRefs* best_refs; uint16_t* const histogram_symbols = (uint16_t*)WebPSafeMalloc(histogram_image_xysize, sizeof(*histogram_symbols)); assert(histogram_bits >= MIN_HUFFMAN_BITS); assert(histogram_bits <= MAX_HUFFMAN_BITS); assert(hdr_size != NULL); assert(data_size != NULL); VP8LBackwardRefsInit(&refs, refs_array[0].block_size_); if (histogram_symbols == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } *cache_bits = use_cache ? MAX_COLOR_CACHE_BITS : 0; // 'best_refs' is the reference to the best backward refs and points to one // of refs_array[0] or refs_array[1]. // Calculate backward references from ARGB image. if (VP8LHashChainFill(hash_chain, quality, argb, width, height) == 0) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } best_refs = VP8LGetBackwardReferences(width, height, argb, quality, low_effort, cache_bits, hash_chain, refs_array); if (best_refs == NULL || !VP8LBackwardRefsCopy(best_refs, &refs)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } histogram_image = VP8LAllocateHistogramSet(histogram_image_xysize, *cache_bits); tmp_histos = VP8LAllocateHistogramSet(2, *cache_bits); if (histogram_image == NULL || tmp_histos == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Build histogram image and symbols from backward references. if (!VP8LGetHistoImageSymbols(width, height, &refs, quality, low_effort, histogram_bits, *cache_bits, histogram_image, tmp_histos, histogram_symbols)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Create Huffman bit lengths and codes for each histogram image. histogram_image_size = histogram_image->size; bit_array_size = 5 * histogram_image_size; huffman_codes = (HuffmanTreeCode*)WebPSafeCalloc(bit_array_size, sizeof(*huffman_codes)); // Note: some histogram_image entries may point to tmp_histos[], so the latter // need to outlive the following call to GetHuffBitLengthsAndCodes(). if (huffman_codes == NULL || !GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Free combined histograms. VP8LFreeHistogramSet(histogram_image); histogram_image = NULL; // Free scratch histograms. VP8LFreeHistogramSet(tmp_histos); tmp_histos = NULL; // Color Cache parameters. if (*cache_bits > 0) { VP8LPutBits(bw, 1, 1); VP8LPutBits(bw, *cache_bits, 4); } else { VP8LPutBits(bw, 0, 1); } // Huffman image + meta huffman. { const int write_histogram_image = (histogram_image_size > 1); VP8LPutBits(bw, write_histogram_image, 1); if (write_histogram_image) { uint32_t* const histogram_argb = (uint32_t*)WebPSafeMalloc(histogram_image_xysize, sizeof(*histogram_argb)); int max_index = 0; uint32_t i; if (histogram_argb == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } for (i = 0; i < histogram_image_xysize; ++i) { const int symbol_index = histogram_symbols[i] & 0xffff; histogram_argb[i] = (symbol_index << 8); if (symbol_index >= max_index) { max_index = symbol_index + 1; } } histogram_image_size = max_index; VP8LPutBits(bw, histogram_bits - 2, 3); err = EncodeImageNoHuffman(bw, histogram_argb, hash_chain, refs_array, VP8LSubSampleSize(width, histogram_bits), VP8LSubSampleSize(height, histogram_bits), quality); WebPSafeFree(histogram_argb); if (err != VP8_ENC_OK) goto Error; } } // Store Huffman codes. { int i; int max_tokens = 0; huff_tree = (HuffmanTree*)WebPSafeMalloc(3ULL * CODE_LENGTH_CODES, sizeof(*huff_tree)); if (huff_tree == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Find maximum number of symbols for the huffman tree-set. for (i = 0; i < 5 * histogram_image_size; ++i) { HuffmanTreeCode* const codes = &huffman_codes[i]; if (max_tokens < codes->num_symbols) { max_tokens = codes->num_symbols; } } tokens = (HuffmanTreeToken*)WebPSafeMalloc(max_tokens, sizeof(*tokens)); if (tokens == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } for (i = 0; i < 5 * histogram_image_size; ++i) { HuffmanTreeCode* const codes = &huffman_codes[i]; StoreHuffmanCode(bw, huff_tree, tokens, codes); ClearHuffmanTreeIfOnlyOneSymbol(codes); } } *hdr_size = (int)(VP8LBitWriterNumBytes(bw) - init_byte_position); // Store actual literals. err = StoreImageToBitMask(bw, width, histogram_bits, &refs, histogram_symbols, huffman_codes); *data_size = (int)(VP8LBitWriterNumBytes(bw) - init_byte_position - *hdr_size); Error: WebPSafeFree(tokens); WebPSafeFree(huff_tree); VP8LFreeHistogramSet(histogram_image); VP8LFreeHistogramSet(tmp_histos); VP8LBackwardRefsClear(&refs); if (huffman_codes != NULL) { WebPSafeFree(huffman_codes->codes); WebPSafeFree(huffman_codes); } WebPSafeFree(histogram_symbols); return err; } // ----------------------------------------------------------------------------- // Transforms static void ApplySubtractGreen(VP8LEncoder* const enc, int width, int height, VP8LBitWriter* const bw) { VP8LPutBits(bw, TRANSFORM_PRESENT, 1); VP8LPutBits(bw, SUBTRACT_GREEN, 2); VP8LSubtractGreenFromBlueAndRed(enc->argb_, width * height); } static WebPEncodingError ApplyPredictFilter(const VP8LEncoder* const enc, int width, int height, int quality, int low_effort, int used_subtract_green, VP8LBitWriter* const bw) { const int pred_bits = enc->transform_bits_; const int transform_width = VP8LSubSampleSize(width, pred_bits); const int transform_height = VP8LSubSampleSize(height, pred_bits); // we disable near-lossless quantization if palette is used. const int near_lossless_strength = enc->use_palette_ ? 100 : enc->config_->near_lossless; VP8LResidualImage(width, height, pred_bits, low_effort, enc->argb_, enc->argb_scratch_, enc->transform_data_, near_lossless_strength, enc->config_->exact, used_subtract_green); VP8LPutBits(bw, TRANSFORM_PRESENT, 1); VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2); assert(pred_bits >= 2); VP8LPutBits(bw, pred_bits - 2, 3); return EncodeImageNoHuffman(bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_, (VP8LBackwardRefs*)enc->refs_, // cast const away transform_width, transform_height, quality); } static WebPEncodingError ApplyCrossColorFilter(const VP8LEncoder* const enc, int width, int height, int quality, VP8LBitWriter* const bw) { const int ccolor_transform_bits = enc->transform_bits_; const int transform_width = VP8LSubSampleSize(width, ccolor_transform_bits); const int transform_height = VP8LSubSampleSize(height, ccolor_transform_bits); VP8LColorSpaceTransform(width, height, ccolor_transform_bits, quality, enc->argb_, enc->transform_data_); VP8LPutBits(bw, TRANSFORM_PRESENT, 1); VP8LPutBits(bw, CROSS_COLOR_TRANSFORM, 2); assert(ccolor_transform_bits >= 2); VP8LPutBits(bw, ccolor_transform_bits - 2, 3); return EncodeImageNoHuffman(bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_, (VP8LBackwardRefs*)enc->refs_, // cast const away transform_width, transform_height, quality); } // ----------------------------------------------------------------------------- static WebPEncodingError WriteRiffHeader(const WebPPicture* const pic, size_t riff_size, size_t vp8l_size) { uint8_t riff[RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE + VP8L_SIGNATURE_SIZE] = { 'R', 'I', 'F', 'F', 0, 0, 0, 0, 'W', 'E', 'B', 'P', 'V', 'P', '8', 'L', 0, 0, 0, 0, VP8L_MAGIC_BYTE, }; PutLE32(riff + TAG_SIZE, (uint32_t)riff_size); PutLE32(riff + RIFF_HEADER_SIZE + TAG_SIZE, (uint32_t)vp8l_size); if (!pic->writer(riff, sizeof(riff), pic)) { return VP8_ENC_ERROR_BAD_WRITE; } return VP8_ENC_OK; } static int WriteImageSize(const WebPPicture* const pic, VP8LBitWriter* const bw) { const int width = pic->width - 1; const int height = pic->height - 1; assert(width < WEBP_MAX_DIMENSION && height < WEBP_MAX_DIMENSION); VP8LPutBits(bw, width, VP8L_IMAGE_SIZE_BITS); VP8LPutBits(bw, height, VP8L_IMAGE_SIZE_BITS); return !bw->error_; } static int WriteRealAlphaAndVersion(VP8LBitWriter* const bw, int has_alpha) { VP8LPutBits(bw, has_alpha, 1); VP8LPutBits(bw, VP8L_VERSION, VP8L_VERSION_BITS); return !bw->error_; } static WebPEncodingError WriteImage(const WebPPicture* const pic, VP8LBitWriter* const bw, size_t* const coded_size) { WebPEncodingError err = VP8_ENC_OK; const uint8_t* const webpll_data = VP8LBitWriterFinish(bw); const size_t webpll_size = VP8LBitWriterNumBytes(bw); const size_t vp8l_size = VP8L_SIGNATURE_SIZE + webpll_size; const size_t pad = vp8l_size & 1; const size_t riff_size = TAG_SIZE + CHUNK_HEADER_SIZE + vp8l_size + pad; err = WriteRiffHeader(pic, riff_size, vp8l_size); if (err != VP8_ENC_OK) goto Error; if (!pic->writer(webpll_data, webpll_size, pic)) { err = VP8_ENC_ERROR_BAD_WRITE; goto Error; } if (pad) { const uint8_t pad_byte[1] = { 0 }; if (!pic->writer(pad_byte, 1, pic)) { err = VP8_ENC_ERROR_BAD_WRITE; goto Error; } } *coded_size = CHUNK_HEADER_SIZE + riff_size; return VP8_ENC_OK; Error: return err; } // ----------------------------------------------------------------------------- static void ClearTransformBuffer(VP8LEncoder* const enc) { WebPSafeFree(enc->transform_mem_); enc->transform_mem_ = NULL; enc->transform_mem_size_ = 0; } // Allocates the memory for argb (W x H) buffer, 2 rows of context for // prediction and transform data. // Flags influencing the memory allocated: // enc->transform_bits_ // enc->use_predict_, enc->use_cross_color_ static WebPEncodingError AllocateTransformBuffer(VP8LEncoder* const enc, int width, int height) { WebPEncodingError err = VP8_ENC_OK; const uint64_t image_size = width * height; // VP8LResidualImage needs room for 2 scanlines of uint32 pixels with an extra // pixel in each, plus 2 regular scanlines of bytes. // TODO(skal): Clean up by using arithmetic in bytes instead of words. const uint64_t argb_scratch_size = enc->use_predict_ ? (width + 1) * 2 + (width * 2 + sizeof(uint32_t) - 1) / sizeof(uint32_t) : 0; const uint64_t transform_data_size = (enc->use_predict_ || enc->use_cross_color_) ? VP8LSubSampleSize(width, enc->transform_bits_) * VP8LSubSampleSize(height, enc->transform_bits_) : 0; const uint64_t max_alignment_in_words = (WEBP_ALIGN_CST + sizeof(uint32_t) - 1) / sizeof(uint32_t); const uint64_t mem_size = image_size + max_alignment_in_words + argb_scratch_size + max_alignment_in_words + transform_data_size; uint32_t* mem = enc->transform_mem_; if (mem == NULL || mem_size > enc->transform_mem_size_) { ClearTransformBuffer(enc); mem = (uint32_t*)WebPSafeMalloc(mem_size, sizeof(*mem)); if (mem == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } enc->transform_mem_ = mem; enc->transform_mem_size_ = (size_t)mem_size; } enc->argb_ = mem; mem = (uint32_t*)WEBP_ALIGN(mem + image_size); enc->argb_scratch_ = mem; mem = (uint32_t*)WEBP_ALIGN(mem + argb_scratch_size); enc->transform_data_ = mem; enc->current_width_ = width; Error: return err; } static WebPEncodingError MakeInputImageCopy(VP8LEncoder* const enc) { WebPEncodingError err = VP8_ENC_OK; const WebPPicture* const picture = enc->pic_; const int width = picture->width; const int height = picture->height; int y; err = AllocateTransformBuffer(enc, width, height); if (err != VP8_ENC_OK) return err; for (y = 0; y < height; ++y) { memcpy(enc->argb_ + y * width, picture->argb + y * picture->argb_stride, width * sizeof(*enc->argb_)); } assert(enc->current_width_ == width); return VP8_ENC_OK; } // ----------------------------------------------------------------------------- static int SearchColor(const uint32_t sorted[], uint32_t color, int hi) { int low = 0; if (sorted[low] == color) return low; // loop invariant: sorted[low] != color while (1) { const int mid = (low + hi) >> 1; if (sorted[mid] == color) { return mid; } else if (sorted[mid] < color) { low = mid; } else { hi = mid; } } } // Sort palette in increasing order and prepare an inverse mapping array. static void PrepareMapToPalette(const uint32_t palette[], int num_colors, uint32_t sorted[], int idx_map[]) { int i; memcpy(sorted, palette, num_colors * sizeof(*sorted)); qsort(sorted, num_colors, sizeof(*sorted), PaletteCompareColorsForQsort); for (i = 0; i < num_colors; ++i) { idx_map[SearchColor(sorted, palette[i], num_colors)] = i; } } static void MapToPalette(const uint32_t sorted_palette[], int num_colors, uint32_t* const last_pix, int* const last_idx, const int idx_map[], const uint32_t* src, uint8_t* dst, int width) { int x; int prev_idx = *last_idx; uint32_t prev_pix = *last_pix; for (x = 0; x < width; ++x) { const uint32_t pix = src[x]; if (pix != prev_pix) { prev_idx = idx_map[SearchColor(sorted_palette, pix, num_colors)]; prev_pix = pix; } dst[x] = prev_idx; } *last_idx = prev_idx; *last_pix = prev_pix; } // Remap argb values in src[] to packed palettes entries in dst[] // using 'row' as a temporary buffer of size 'width'. // We assume that all src[] values have a corresponding entry in the palette. // Note: src[] can be the same as dst[] static WebPEncodingError 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) { // TODO(skal): this tmp buffer is not needed if VP8LBundleColorMap() can be // made to work in-place. uint8_t* const tmp_row = (uint8_t*)WebPSafeMalloc(width, sizeof(*tmp_row)); int i, x, y; int use_LUT = 1; if (tmp_row == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY; for (i = 0; i < palette_size; ++i) { if ((palette[i] & 0xffff00ffu) != 0) { use_LUT = 0; break; } } if (use_LUT) { uint8_t inv_palette[MAX_PALETTE_SIZE] = { 0 }; for (i = 0; i < palette_size; ++i) { const int color = (palette[i] >> 8) & 0xff; inv_palette[color] = i; } for (y = 0; y < height; ++y) { for (x = 0; x < width; ++x) { const int color = (src[x] >> 8) & 0xff; tmp_row[x] = inv_palette[color]; } VP8LBundleColorMap(tmp_row, width, xbits, dst); src += src_stride; dst += dst_stride; } } else { // Use 1 pixel cache for ARGB pixels. uint32_t last_pix; int last_idx; uint32_t sorted[MAX_PALETTE_SIZE]; int idx_map[MAX_PALETTE_SIZE]; PrepareMapToPalette(palette, palette_size, sorted, idx_map); last_pix = palette[0]; last_idx = 0; for (y = 0; y < height; ++y) { MapToPalette(sorted, palette_size, &last_pix, &last_idx, idx_map, src, tmp_row, width); VP8LBundleColorMap(tmp_row, width, xbits, dst); src += src_stride; dst += dst_stride; } } WebPSafeFree(tmp_row); return VP8_ENC_OK; } // Note: Expects "enc->palette_" to be set properly. static WebPEncodingError MapImageFromPalette(VP8LEncoder* const enc, int in_place) { WebPEncodingError err = VP8_ENC_OK; const WebPPicture* const pic = enc->pic_; const int width = pic->width; const int height = pic->height; const uint32_t* const palette = enc->palette_; const uint32_t* src = in_place ? enc->argb_ : pic->argb; const int src_stride = in_place ? enc->current_width_ : pic->argb_stride; const int palette_size = enc->palette_size_; int xbits; // Replace each input pixel by corresponding palette index. // This is done line by line. if (palette_size <= 4) { xbits = (palette_size <= 2) ? 3 : 2; } else { xbits = (palette_size <= 16) ? 1 : 0; } err = AllocateTransformBuffer(enc, VP8LSubSampleSize(width, xbits), height); if (err != VP8_ENC_OK) return err; err = ApplyPalette(src, src_stride, enc->argb_, enc->current_width_, palette, palette_size, width, height, xbits); return err; } // Save palette_[] to bitstream. static WebPEncodingError EncodePalette(VP8LBitWriter* const bw, VP8LEncoder* const enc) { int i; uint32_t tmp_palette[MAX_PALETTE_SIZE]; const int palette_size = enc->palette_size_; const uint32_t* const palette = enc->palette_; VP8LPutBits(bw, TRANSFORM_PRESENT, 1); VP8LPutBits(bw, COLOR_INDEXING_TRANSFORM, 2); assert(palette_size >= 1 && palette_size <= MAX_PALETTE_SIZE); VP8LPutBits(bw, palette_size - 1, 8); for (i = palette_size - 1; i >= 1; --i) { tmp_palette[i] = VP8LSubPixels(palette[i], palette[i - 1]); } tmp_palette[0] = palette[0]; return EncodeImageNoHuffman(bw, tmp_palette, &enc->hash_chain_, enc->refs_, palette_size, 1, 20 /* quality */); } #ifdef WEBP_EXPERIMENTAL_FEATURES static WebPEncodingError EncodeDeltaPalettePredictorImage( VP8LBitWriter* const bw, VP8LEncoder* const enc, int quality) { const WebPPicture* const pic = enc->pic_; const int width = pic->width; const int height = pic->height; const int pred_bits = 5; const int transform_width = VP8LSubSampleSize(width, pred_bits); const int transform_height = VP8LSubSampleSize(height, pred_bits); const int pred = 7; // default is Predictor7 (Top/Left Average) const int tiles_per_row = VP8LSubSampleSize(width, pred_bits); const int tiles_per_col = VP8LSubSampleSize(height, pred_bits); uint32_t* predictors; int tile_x, tile_y; WebPEncodingError err = VP8_ENC_OK; predictors = (uint32_t*)WebPSafeMalloc(tiles_per_col * tiles_per_row, sizeof(*predictors)); if (predictors == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY; for (tile_y = 0; tile_y < tiles_per_col; ++tile_y) { for (tile_x = 0; tile_x < tiles_per_row; ++tile_x) { predictors[tile_y * tiles_per_row + tile_x] = 0xff000000u | (pred << 8); } } VP8LPutBits(bw, TRANSFORM_PRESENT, 1); VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2); VP8LPutBits(bw, pred_bits - 2, 3); err = EncodeImageNoHuffman(bw, predictors, &enc->hash_chain_, (VP8LBackwardRefs*)enc->refs_, // cast const away transform_width, transform_height, quality); WebPSafeFree(predictors); return err; } #endif // WEBP_EXPERIMENTAL_FEATURES // ----------------------------------------------------------------------------- // VP8LEncoder static VP8LEncoder* VP8LEncoderNew(const WebPConfig* const config, const WebPPicture* const picture) { VP8LEncoder* const enc = (VP8LEncoder*)WebPSafeCalloc(1ULL, sizeof(*enc)); if (enc == NULL) { WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY); return NULL; } enc->config_ = config; enc->pic_ = picture; VP8LEncDspInit(); return enc; } static void VP8LEncoderDelete(VP8LEncoder* enc) { if (enc != NULL) { VP8LHashChainClear(&enc->hash_chain_); VP8LBackwardRefsClear(&enc->refs_[0]); VP8LBackwardRefsClear(&enc->refs_[1]); ClearTransformBuffer(enc); WebPSafeFree(enc); } } // ----------------------------------------------------------------------------- // Main call WebPEncodingError VP8LEncodeStream(const WebPConfig* const config, const WebPPicture* const picture, VP8LBitWriter* const bw, int use_cache) { WebPEncodingError err = VP8_ENC_OK; const int quality = (int)config->quality; const int low_effort = (config->method == 0); const int width = picture->width; const int height = picture->height; VP8LEncoder* const enc = VP8LEncoderNew(config, picture); const size_t byte_position = VP8LBitWriterNumBytes(bw); int use_near_lossless = 0; int hdr_size = 0; int data_size = 0; int use_delta_palettization = 0; if (enc == NULL) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // --------------------------------------------------------------------------- // Analyze image (entropy, num_palettes etc) if (!AnalyzeAndInit(enc)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } // Apply near-lossless preprocessing. use_near_lossless = (config->near_lossless < 100) && !enc->use_palette_ && !enc->use_predict_; if (use_near_lossless) { if (!VP8ApplyNearLossless(width, height, picture->argb, config->near_lossless)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } } #ifdef WEBP_EXPERIMENTAL_FEATURES if (config->delta_palettization) { enc->use_predict_ = 1; enc->use_cross_color_ = 0; enc->use_subtract_green_ = 0; enc->use_palette_ = 1; err = MakeInputImageCopy(enc); if (err != VP8_ENC_OK) goto Error; err = WebPSearchOptimalDeltaPalette(enc); if (err != VP8_ENC_OK) goto Error; if (enc->use_palette_) { err = AllocateTransformBuffer(enc, width, height); if (err != VP8_ENC_OK) goto Error; err = EncodeDeltaPalettePredictorImage(bw, enc, quality); if (err != VP8_ENC_OK) goto Error; use_delta_palettization = 1; } } #endif // WEBP_EXPERIMENTAL_FEATURES // Encode palette if (enc->use_palette_) { err = EncodePalette(bw, enc); if (err != VP8_ENC_OK) goto Error; err = MapImageFromPalette(enc, use_delta_palettization); if (err != VP8_ENC_OK) goto Error; } if (!use_delta_palettization) { // In case image is not packed. if (enc->argb_ == NULL) { err = MakeInputImageCopy(enc); if (err != VP8_ENC_OK) goto Error; } // ------------------------------------------------------------------------- // Apply transforms and write transform data. if (enc->use_subtract_green_) { ApplySubtractGreen(enc, enc->current_width_, height, bw); } if (enc->use_predict_) { err = ApplyPredictFilter(enc, enc->current_width_, height, quality, low_effort, enc->use_subtract_green_, bw); if (err != VP8_ENC_OK) goto Error; } if (enc->use_cross_color_) { err = ApplyCrossColorFilter(enc, enc->current_width_, height, quality, bw); if (err != VP8_ENC_OK) goto Error; } } VP8LPutBits(bw, !TRANSFORM_PRESENT, 1); // No more transforms. // --------------------------------------------------------------------------- // Encode and write the transformed image. err = EncodeImageInternal(bw, enc->argb_, &enc->hash_chain_, enc->refs_, enc->current_width_, height, quality, low_effort, use_cache, &enc->cache_bits_, enc->histo_bits_, byte_position, &hdr_size, &data_size); if (err != VP8_ENC_OK) goto Error; if (picture->stats != NULL) { WebPAuxStats* const stats = picture->stats; stats->lossless_features = 0; if (enc->use_predict_) stats->lossless_features |= 1; if (enc->use_cross_color_) stats->lossless_features |= 2; if (enc->use_subtract_green_) stats->lossless_features |= 4; if (enc->use_palette_) stats->lossless_features |= 8; stats->histogram_bits = enc->histo_bits_; stats->transform_bits = enc->transform_bits_; stats->cache_bits = enc->cache_bits_; stats->palette_size = enc->palette_size_; stats->lossless_size = (int)(VP8LBitWriterNumBytes(bw) - byte_position); stats->lossless_hdr_size = hdr_size; stats->lossless_data_size = data_size; } Error: VP8LEncoderDelete(enc); return err; } int VP8LEncodeImage(const WebPConfig* const config, const WebPPicture* const picture) { int width, height; int has_alpha; size_t coded_size; int percent = 0; int initial_size; WebPEncodingError err = VP8_ENC_OK; VP8LBitWriter bw; if (picture == NULL) return 0; if (config == NULL || picture->argb == NULL) { err = VP8_ENC_ERROR_NULL_PARAMETER; WebPEncodingSetError(picture, err); return 0; } width = picture->width; height = picture->height; // Initialize BitWriter with size corresponding to 16 bpp to photo images and // 8 bpp for graphical images. initial_size = (config->image_hint == WEBP_HINT_GRAPH) ? width * height : width * height * 2; if (!VP8LBitWriterInit(&bw, initial_size)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } if (!WebPReportProgress(picture, 1, &percent)) { UserAbort: err = VP8_ENC_ERROR_USER_ABORT; goto Error; } // Reset stats (for pure lossless coding) if (picture->stats != NULL) { WebPAuxStats* const stats = picture->stats; memset(stats, 0, sizeof(*stats)); stats->PSNR[0] = 99.f; stats->PSNR[1] = 99.f; stats->PSNR[2] = 99.f; stats->PSNR[3] = 99.f; stats->PSNR[4] = 99.f; } // Write image size. if (!WriteImageSize(picture, &bw)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } has_alpha = WebPPictureHasTransparency(picture); // Write the non-trivial Alpha flag and lossless version. if (!WriteRealAlphaAndVersion(&bw, has_alpha)) { err = VP8_ENC_ERROR_OUT_OF_MEMORY; goto Error; } if (!WebPReportProgress(picture, 5, &percent)) goto UserAbort; // Encode main image stream. err = VP8LEncodeStream(config, picture, &bw, 1 /*use_cache*/); if (err != VP8_ENC_OK) goto Error; // TODO(skal): have a fine-grained progress report in VP8LEncodeStream(). if (!WebPReportProgress(picture, 90, &percent)) goto UserAbort; // Finish the RIFF chunk. err = WriteImage(picture, &bw, &coded_size); if (err != VP8_ENC_OK) goto Error; if (!WebPReportProgress(picture, 100, &percent)) goto UserAbort; // Save size. if (picture->stats != NULL) { picture->stats->coded_size += (int)coded_size; picture->stats->lossless_size = (int)coded_size; } if (picture->extra_info != NULL) { const int mb_w = (width + 15) >> 4; const int mb_h = (height + 15) >> 4; memset(picture->extra_info, 0, mb_w * mb_h * sizeof(*picture->extra_info)); } Error: if (bw.error_) err = VP8_ENC_ERROR_OUT_OF_MEMORY; VP8LBitWriterWipeOut(&bw); if (err != VP8_ENC_OK) { WebPEncodingSetError(picture, err); return 0; } return 1; } //------------------------------------------------------------------------------