diff options
Diffstat (limited to 'src/3rdparty/libwebp/src/enc/vp8l_enc.c')
| -rw-r--r-- | src/3rdparty/libwebp/src/enc/vp8l_enc.c | 1667 |
1 files changed, 1667 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/enc/vp8l_enc.c b/src/3rdparty/libwebp/src/enc/vp8l_enc.c new file mode 100644 index 0000000..b1a793d --- /dev/null +++ b/src/3rdparty/libwebp/src/enc/vp8l_enc.c @@ -0,0 +1,1667 @@ +// 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 <assert.h> +#include <stdlib.h> + +#include "./backward_references_enc.h" +#include "./histogram_enc.h" +#include "./vp8i_enc.h" +#include "./vp8li_enc.h" +#include "../dsp/lossless.h" +#include "../dsp/lossless_common.h" +#include "../utils/bit_writer_utils.h" +#include "../utils/huffman_encode_utils.h" +#include "../utils/utils.h" +#include "../webp/format_constants.h" + +#include "./delta_palettization_enc.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((uint8_t*)p1); + const uint32_t b = WebPMemToUint32((uint8_t*)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(int p, uint32_t* const r, uint32_t* const b) { + const int green = p >> 8; // The upper bits are masked away later. + ++r[((p >> 16) - green) & 0xff]; + ++b[((p >> 0) - green) & 0xff]; +} + +static void AddSingle(uint32_t p, + uint32_t* const a, uint32_t* const r, + uint32_t* const g, uint32_t* const b) { + ++a[(p >> 24) & 0xff]; + ++r[(p >> 16) & 0xff]; + ++g[(p >> 8) & 0xff]; + ++b[(p >> 0) & 0xff]; +} + +static WEBP_INLINE uint32_t HashPix(uint32_t pix) { + // Note that masking with 0xffffffffu is for preventing an + // 'unsigned int overflow' warning. Doesn't impact the compiled code. + return ((((uint64_t)pix + (pix >> 19)) * 0x39c5fba7ull) & 0xffffffffu) >> 24; +} + +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 uint32_t hash = HashPix(pix); + ++histo[kHistoPalette * 256 + hash]; + } + } + prev_row = curr_row; + curr_row += argb_stride; + } + { + double entropy_comp[kHistoTotal]; + double entropy[kNumEntropyIx]; + int k; + int 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 = (EntropyIx)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; + const int res = + (histo_bits > max_transform_bits) ? max_transform_bits : histo_bits; + assert(res <= MAX_TRANSFORM_BITS); + return res; +} + +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 low_effort) { + 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, + low_effort)) { + 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; + } + + if (use_cache) { + // If the value is different from zero, it has been set during the + // palette analysis. + if (*cache_bits == 0) *cache_bits = MAX_COLOR_CACHE_BITS; + } else { + *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, + low_effort)) { + 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, low_effort); + 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, low_effort); +} + +static WebPEncodingError ApplyCrossColorFilter(const VP8LEncoder* const enc, + int width, int height, + int quality, int low_effort, + 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, low_effort); +} + +// ----------------------------------------------------------------------------- + +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 WEBP_INLINE int SearchColorNoIdx(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; + } + } +} + +#define APPLY_PALETTE_GREEDY_MAX 4 + +static WEBP_INLINE uint32_t SearchColorGreedy(const uint32_t palette[], + int palette_size, + uint32_t color) { + (void)palette_size; + assert(palette_size < APPLY_PALETTE_GREEDY_MAX); + assert(3 == APPLY_PALETTE_GREEDY_MAX - 1); + if (color == palette[0]) return 0; + if (color == palette[1]) return 1; + if (color == palette[2]) return 2; + return 3; +} + +static WEBP_INLINE uint32_t ApplyPaletteHash0(uint32_t color) { + // Focus on the green color. + return (color >> 8) & 0xff; +} + +#define PALETTE_INV_SIZE_BITS 11 +#define PALETTE_INV_SIZE (1 << PALETTE_INV_SIZE_BITS) + +static WEBP_INLINE uint32_t ApplyPaletteHash1(uint32_t color) { + // Forget about alpha. + return ((color & 0x00ffffffu) * 4222244071u) >> (32 - PALETTE_INV_SIZE_BITS); +} + +static WEBP_INLINE uint32_t ApplyPaletteHash2(uint32_t color) { + // Forget about alpha. + return (color & 0x00ffffffu) * ((1u << 31) - 1) >> + (32 - PALETTE_INV_SIZE_BITS); +} + +// Sort palette in increasing order and prepare an inverse mapping array. +static void PrepareMapToPalette(const uint32_t palette[], int num_colors, + uint32_t sorted[], uint32_t 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[SearchColorNoIdx(sorted, palette[i], num_colors)] = i; + } +} + +// Use 1 pixel cache for ARGB pixels. +#define APPLY_PALETTE_FOR(COLOR_INDEX) do { \ + uint32_t prev_pix = palette[0]; \ + uint32_t prev_idx = 0; \ + for (y = 0; y < height; ++y) { \ + for (x = 0; x < width; ++x) { \ + const uint32_t pix = src[x]; \ + if (pix != prev_pix) { \ + prev_idx = COLOR_INDEX; \ + prev_pix = pix; \ + } \ + tmp_row[x] = prev_idx; \ + } \ + VP8LBundleColorMap(tmp_row, width, xbits, dst); \ + src += src_stride; \ + dst += dst_stride; \ + } \ +} while (0) + +// 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 x, y; + + if (tmp_row == NULL) return VP8_ENC_ERROR_OUT_OF_MEMORY; + + if (palette_size < APPLY_PALETTE_GREEDY_MAX) { + APPLY_PALETTE_FOR(SearchColorGreedy(palette, palette_size, pix)); + } else { + int i, j; + uint16_t buffer[PALETTE_INV_SIZE]; + uint32_t (*const hash_functions[])(uint32_t) = { + ApplyPaletteHash0, ApplyPaletteHash1, ApplyPaletteHash2 + }; + + // Try to find a perfect hash function able to go from a color to an index + // within 1 << PALETTE_INV_SIZE_BITS in order to build a hash map to go + // from color to index in palette. + for (i = 0; i < 3; ++i) { + int use_LUT = 1; + // Set each element in buffer to max uint16_t. + memset(buffer, 0xff, sizeof(buffer)); + for (j = 0; j < palette_size; ++j) { + const uint32_t ind = hash_functions[i](palette[j]); + if (buffer[ind] != 0xffffu) { + use_LUT = 0; + break; + } else { + buffer[ind] = j; + } + } + if (use_LUT) break; + } + + if (i == 0) { + APPLY_PALETTE_FOR(buffer[ApplyPaletteHash0(pix)]); + } else if (i == 1) { + APPLY_PALETTE_FOR(buffer[ApplyPaletteHash1(pix)]); + } else if (i == 2) { + APPLY_PALETTE_FOR(buffer[ApplyPaletteHash2(pix)]); + } else { + uint32_t idx_map[MAX_PALETTE_SIZE]; + uint32_t palette_sorted[MAX_PALETTE_SIZE]; + PrepareMapToPalette(palette, palette_size, palette_sorted, idx_map); + APPLY_PALETTE_FOR( + idx_map[SearchColorNoIdx(palette_sorted, pix, palette_size)]); + } + } + WebPSafeFree(tmp_row); + return VP8_ENC_OK; +} +#undef APPLY_PALETTE_FOR +#undef PALETTE_INV_SIZE_BITS +#undef PALETTE_INV_SIZE +#undef APPLY_PALETTE_GREEDY_MAX + +// 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, int low_effort, + 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 */, low_effort); +} + +#ifdef WEBP_EXPERIMENTAL_FEATURES + +static WebPEncodingError EncodeDeltaPalettePredictorImage( + VP8LBitWriter* const bw, VP8LEncoder* const enc, int quality, + int low_effort) { + 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, low_effort); + 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_palette = 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->use_delta_palette) { + 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, low_effort); + if (err != VP8_ENC_OK) goto Error; + use_delta_palette = 1; + } + } +#endif // WEBP_EXPERIMENTAL_FEATURES + + // Encode palette + if (enc->use_palette_) { + err = EncodePalette(bw, low_effort, enc); + if (err != VP8_ENC_OK) goto Error; + err = MapImageFromPalette(enc, use_delta_palette); + if (err != VP8_ENC_OK) goto Error; + // If using a color cache, do not have it bigger than the number of colors. + if (use_cache && enc->palette_size_ < (1 << MAX_COLOR_CACHE_BITS)) { + enc->cache_bits_ = BitsLog2Floor(enc->palette_size_) + 1; + } + } + if (!use_delta_palette) { + // 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, low_effort, 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; +} + +//------------------------------------------------------------------------------ |