diff options
Diffstat (limited to 'drivers/webpold/enc/vp8l.c')
| -rw-r--r-- | drivers/webpold/enc/vp8l.c | 1150 |
1 files changed, 1150 insertions, 0 deletions
diff --git a/drivers/webpold/enc/vp8l.c b/drivers/webpold/enc/vp8l.c new file mode 100644 index 0000000000..f4eb6e783f --- /dev/null +++ b/drivers/webpold/enc/vp8l.c @@ -0,0 +1,1150 @@ +// Copyright 2012 Google Inc. All Rights Reserved. +// +// This code is licensed under the same terms as WebM: +// Software License Agreement: http://www.webmproject.org/license/software/ +// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ +// ----------------------------------------------------------------------------- +// +// main entry for the lossless encoder. +// +// Author: Vikas Arora (vikaas.arora@gmail.com) +// + +#include <assert.h> +#include <stdio.h> +#include <stdlib.h> + +#include "./backward_references.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 "../format_constants.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#define PALETTE_KEY_RIGHT_SHIFT 22 // Key for 1K buffer. +#define MAX_HUFF_IMAGE_SIZE (16 * 1024 * 1024) +#define MAX_COLORS_FOR_GRAPH 64 + +// ----------------------------------------------------------------------------- +// Palette + +static int CompareColors(const void* p1, const void* p2) { + const uint32_t a = *(const uint32_t*)p1; + const uint32_t b = *(const uint32_t*)p2; + return (a < b) ? -1 : (a > b) ? 1 : 0; +} + +// 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, + uint32_t palette[MAX_PALETTE_SIZE], + int* const palette_size) { + int i, x, y, key; + int num_colors = 0; + uint8_t in_use[MAX_PALETTE_SIZE * 4] = { 0 }; + uint32_t colors[MAX_PALETTE_SIZE * 4]; + static const uint32_t kHashMul = 0x1e35a7bd; + const uint32_t* argb = pic->argb; + const int width = pic->width; + const int height = pic->height; + uint32_t last_pix = ~argb[0]; // so we're sure that last_pix != argb[0] + + for (y = 0; y < height; ++y) { + for (x = 0; x < width; ++x) { + if (argb[x] == last_pix) { + continue; + } + last_pix = argb[x]; + key = (kHashMul * last_pix) >> PALETTE_KEY_RIGHT_SHIFT; + while (1) { + if (!in_use[key]) { + colors[key] = last_pix; + in_use[key] = 1; + ++num_colors; + if (num_colors > MAX_PALETTE_SIZE) { + return 0; + } + break; + } else if (colors[key] == last_pix) { + // The color is already there. + break; + } else { + // Some other color sits there. + // Do linear conflict resolution. + ++key; + key &= (MAX_PALETTE_SIZE * 4 - 1); // key mask for 1K buffer. + } + } + } + argb += pic->argb_stride; + } + + // TODO(skal): could we reuse in_use[] to speed up ApplyPalette()? + num_colors = 0; + for (i = 0; i < (int)(sizeof(in_use) / sizeof(in_use[0])); ++i) { + if (in_use[i]) { + palette[num_colors] = colors[i]; + ++num_colors; + } + } + + qsort(palette, num_colors, sizeof(*palette), CompareColors); + *palette_size = num_colors; + return 1; +} + +static int AnalyzeEntropy(const uint32_t* argb, + int width, int height, int argb_stride, + double* const nonpredicted_bits, + double* const predicted_bits) { + int x, y; + const uint32_t* last_line = NULL; + uint32_t last_pix = argb[0]; // so we're sure that pix_diff == 0 + + VP8LHistogram* nonpredicted = NULL; + VP8LHistogram* predicted = + (VP8LHistogram*)malloc(2 * sizeof(*predicted)); + if (predicted == NULL) return 0; + nonpredicted = predicted + 1; + + VP8LHistogramInit(predicted, 0); + VP8LHistogramInit(nonpredicted, 0); + for (y = 0; y < height; ++y) { + for (x = 0; x < width; ++x) { + const uint32_t pix = argb[x]; + const uint32_t pix_diff = VP8LSubPixels(pix, last_pix); + if (pix_diff == 0) continue; + if (last_line != NULL && pix == last_line[x]) { + continue; + } + last_pix = pix; + { + const PixOrCopy pix_token = PixOrCopyCreateLiteral(pix); + const PixOrCopy pix_diff_token = PixOrCopyCreateLiteral(pix_diff); + VP8LHistogramAddSinglePixOrCopy(nonpredicted, &pix_token); + VP8LHistogramAddSinglePixOrCopy(predicted, &pix_diff_token); + } + } + last_line = argb; + argb += argb_stride; + } + *nonpredicted_bits = VP8LHistogramEstimateBitsBulk(nonpredicted); + *predicted_bits = VP8LHistogramEstimateBitsBulk(predicted); + free(predicted); + return 1; +} + +static int VP8LEncAnalyze(VP8LEncoder* const enc, WebPImageHint image_hint) { + const WebPPicture* const pic = enc->pic_; + assert(pic != NULL && pic->argb != NULL); + + enc->use_palette_ = + AnalyzeAndCreatePalette(pic, enc->palette_, &enc->palette_size_); + + if (image_hint == WEBP_HINT_GRAPH) { + if (enc->use_palette_ && enc->palette_size_ < MAX_COLORS_FOR_GRAPH) { + enc->use_palette_ = 0; + } + } + + if (!enc->use_palette_) { + if (image_hint == WEBP_HINT_PHOTO) { + enc->use_predict_ = 1; + enc->use_cross_color_ = 1; + } else { + double non_pred_entropy, pred_entropy; + if (!AnalyzeEntropy(pic->argb, pic->width, pic->height, pic->argb_stride, + &non_pred_entropy, &pred_entropy)) { + return 0; + } + if (pred_entropy < 0.95 * non_pred_entropy) { + enc->use_predict_ = 1; + // TODO(vikasa): Observed some correlation of cross_color transform with + // predict. Need to investigate this further and add separate heuristic + // for setting use_cross_color flag. + enc->use_cross_color_ = 1; + } + } + } + + return 1; +} + +static int GetHuffBitLengthsAndCodes( + const VP8LHistogramSet* const histogram_image, + HuffmanTreeCode* const huffman_codes) { + int i, k; + int ok = 1; + uint64_t total_length_size = 0; + uint8_t* mem_buf = NULL; + const int histogram_image_size = histogram_image->size; + + // 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) + : (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) { + ok = 0; + 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; + } + } + + // 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]; + ok = ok && VP8LCreateHuffmanTree(histo->literal_, 15, codes + 0); + ok = ok && VP8LCreateHuffmanTree(histo->red_, 15, codes + 1); + ok = ok && VP8LCreateHuffmanTree(histo->blue_, 15, codes + 2); + ok = ok && VP8LCreateHuffmanTree(histo->alpha_, 15, codes + 3); + ok = ok && VP8LCreateHuffmanTree(histo->distance_, 15, codes + 4); + } + + End: + if (!ok) free(mem_buf); + 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; + } + } + VP8LWriteBits(bw, 4, codes_to_store - 4); + for (i = 0; i < codes_to_store; ++i) { + VP8LWriteBits(bw, 3, code_length_bitdepth[kStorageOrder[i]]); + } +} + +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; + VP8LWriteBits(bw, huffman_code->code_lengths[ix], huffman_code->codes[ix]); + switch (ix) { + case 16: + VP8LWriteBits(bw, 2, extra_bits); + break; + case 17: + VP8LWriteBits(bw, 3, extra_bits); + break; + case 18: + VP8LWriteBits(bw, 7, extra_bits); + break; + } + } +} + +static int StoreFullHuffmanCode(VP8LBitWriter* const bw, + const HuffmanTreeCode* const tree) { + int ok = 0; + 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; + HuffmanTreeToken* const tokens = + (HuffmanTreeToken*)WebPSafeMalloc((uint64_t)max_tokens, sizeof(*tokens)); + if (tokens == NULL) return 0; + + huffman_code.num_symbols = CODE_LENGTH_CODES; + huffman_code.code_lengths = code_length_bitdepth; + huffman_code.codes = code_length_bitdepth_symbols; + + VP8LWriteBits(bw, 1, 0); + num_tokens = VP8LCreateCompressedHuffmanTree(tree, tokens, max_tokens); + { + int histogram[CODE_LENGTH_CODES] = { 0 }; + int i; + for (i = 0; i < num_tokens; ++i) { + ++histogram[tokens[i].code]; + } + + if (!VP8LCreateHuffmanTree(histogram, 7, &huffman_code)) { + goto End; + } + } + + 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; + VP8LWriteBits(bw, 1, write_trimmed_length); + if (write_trimmed_length) { + const int nbits = VP8LBitsLog2Ceiling(trimmed_length - 1); + const int nbitpairs = (nbits == 0) ? 1 : (nbits + 1) / 2; + VP8LWriteBits(bw, 3, nbitpairs - 1); + assert(trimmed_length >= 2); + VP8LWriteBits(bw, nbitpairs * 2, trimmed_length - 2); + } + StoreHuffmanTreeToBitMask(bw, tokens, length, &huffman_code); + } + ok = 1; + End: + free(tokens); + return ok; +} + +static int StoreHuffmanCode(VP8LBitWriter* const bw, + 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 + VP8LWriteBits(bw, 4, 0x01); + return 1; + } else if (count <= 2 && symbols[0] < kMaxSymbol && symbols[1] < kMaxSymbol) { + VP8LWriteBits(bw, 1, 1); // Small tree marker to encode 1 or 2 symbols. + VP8LWriteBits(bw, 1, count - 1); + if (symbols[0] <= 1) { + VP8LWriteBits(bw, 1, 0); // Code bit for small (1 bit) symbol value. + VP8LWriteBits(bw, 1, symbols[0]); + } else { + VP8LWriteBits(bw, 1, 1); + VP8LWriteBits(bw, 8, symbols[0]); + } + if (count == 2) { + VP8LWriteBits(bw, 8, symbols[1]); + } + return 1; + } else { + return StoreFullHuffmanCode(bw, huffman_code); + } +} + +static void WriteHuffmanCode(VP8LBitWriter* const bw, + const HuffmanTreeCode* const code, int index) { + const int depth = code->code_lengths[index]; + const int symbol = code->codes[index]; + VP8LWriteBits(bw, depth, symbol); +} + +static void StoreImageToBitMask( + VP8LBitWriter* const bw, int width, int histo_bits, + const VP8LBackwardRefs* const refs, + const uint16_t* histogram_symbols, + const HuffmanTreeCode* const huffman_codes) { + // x and y trace the position in the image. + int x = 0; + int y = 0; + const int histo_xsize = histo_bits ? VP8LSubSampleSize(width, histo_bits) : 1; + int i; + for (i = 0; i < refs->size; ++i) { + const PixOrCopy* const v = &refs->refs[i]; + const int histogram_ix = histogram_symbols[histo_bits ? + (y >> histo_bits) * histo_xsize + + (x >> histo_bits) : 0]; + const HuffmanTreeCode* const codes = huffman_codes + 5 * histogram_ix; + if (PixOrCopyIsCacheIdx(v)) { + const int code = PixOrCopyCacheIdx(v); + const int literal_ix = 256 + NUM_LENGTH_CODES + code; + WriteHuffmanCode(bw, codes, literal_ix); + } else 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 { + int bits, n_bits; + int code, distance; + + PrefixEncode(v->len, &code, &n_bits, &bits); + WriteHuffmanCode(bw, codes, 256 + code); + VP8LWriteBits(bw, n_bits, bits); + + distance = PixOrCopyDistance(v); + PrefixEncode(distance, &code, &n_bits, &bits); + WriteHuffmanCode(bw, codes + 4, code); + VP8LWriteBits(bw, n_bits, bits); + } + x += PixOrCopyLength(v); + while (x >= width) { + x -= width; + ++y; + } + } +} + +// Special case of EncodeImageInternal() for cache-bits=0, histo_bits=31 +static int EncodeImageNoHuffman(VP8LBitWriter* const bw, + const uint32_t* const argb, + int width, int height, int quality) { + int i; + int ok = 0; + VP8LBackwardRefs refs; + HuffmanTreeCode huffman_codes[5] = { { 0, NULL, NULL } }; + const uint16_t histogram_symbols[1] = { 0 }; // only one tree, one symbol + VP8LHistogramSet* const histogram_image = VP8LAllocateHistogramSet(1, 0); + if (histogram_image == NULL) return 0; + + // Calculate backward references from ARGB image. + if (!VP8LGetBackwardReferences(width, height, argb, quality, 0, 1, &refs)) { + 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)) { + goto Error; + } + + // No color cache, no Huffman image. + VP8LWriteBits(bw, 1, 0); + + // Store Huffman codes. + for (i = 0; i < 5; ++i) { + HuffmanTreeCode* const codes = &huffman_codes[i]; + if (!StoreHuffmanCode(bw, codes)) { + goto Error; + } + ClearHuffmanTreeIfOnlyOneSymbol(codes); + } + + // Store actual literals. + StoreImageToBitMask(bw, width, 0, &refs, histogram_symbols, huffman_codes); + ok = 1; + + Error: + free(histogram_image); + VP8LClearBackwardRefs(&refs); + free(huffman_codes[0].codes); + return ok; +} + +static int EncodeImageInternal(VP8LBitWriter* const bw, + const uint32_t* const argb, + int width, int height, int quality, + int cache_bits, int histogram_bits) { + int ok = 0; + const int use_2d_locality = 1; + const int use_color_cache = (cache_bits > 0); + const uint32_t histogram_image_xysize = + VP8LSubSampleSize(width, histogram_bits) * + VP8LSubSampleSize(height, histogram_bits); + VP8LHistogramSet* histogram_image = + VP8LAllocateHistogramSet(histogram_image_xysize, 0); + int histogram_image_size = 0; + size_t bit_array_size = 0; + HuffmanTreeCode* huffman_codes = NULL; + VP8LBackwardRefs refs; + uint16_t* const histogram_symbols = + (uint16_t*)WebPSafeMalloc((uint64_t)histogram_image_xysize, + sizeof(*histogram_symbols)); + assert(histogram_bits >= MIN_HUFFMAN_BITS); + assert(histogram_bits <= MAX_HUFFMAN_BITS); + if (histogram_image == NULL || histogram_symbols == NULL) goto Error; + + // Calculate backward references from ARGB image. + if (!VP8LGetBackwardReferences(width, height, argb, quality, cache_bits, + use_2d_locality, &refs)) { + goto Error; + } + // Build histogram image and symbols from backward references. + if (!VP8LGetHistoImageSymbols(width, height, &refs, + quality, histogram_bits, cache_bits, + histogram_image, + histogram_symbols)) { + 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)); + if (huffman_codes == NULL || + !GetHuffBitLengthsAndCodes(histogram_image, huffman_codes)) { + goto Error; + } + + // Color Cache parameters. + VP8LWriteBits(bw, 1, use_color_cache); + if (use_color_cache) { + VP8LWriteBits(bw, 4, cache_bits); + } + + // Huffman image + meta huffman. + { + const int write_histogram_image = (histogram_image_size > 1); + VP8LWriteBits(bw, 1, write_histogram_image); + if (write_histogram_image) { + uint32_t* const histogram_argb = + (uint32_t*)WebPSafeMalloc((uint64_t)histogram_image_xysize, + sizeof(*histogram_argb)); + int max_index = 0; + uint32_t i; + if (histogram_argb == NULL) goto Error; + for (i = 0; i < histogram_image_xysize; ++i) { + const int index = histogram_symbols[i] & 0xffff; + histogram_argb[i] = 0xff000000 | (index << 8); + if (index >= max_index) { + max_index = index + 1; + } + } + histogram_image_size = max_index; + + VP8LWriteBits(bw, 3, histogram_bits - 2); + ok = EncodeImageNoHuffman(bw, histogram_argb, + VP8LSubSampleSize(width, histogram_bits), + VP8LSubSampleSize(height, histogram_bits), + quality); + free(histogram_argb); + if (!ok) goto Error; + } + } + + // Store Huffman codes. + { + int i; + for (i = 0; i < 5 * histogram_image_size; ++i) { + HuffmanTreeCode* const codes = &huffman_codes[i]; + if (!StoreHuffmanCode(bw, codes)) goto Error; + ClearHuffmanTreeIfOnlyOneSymbol(codes); + } + } + // Free combined histograms. + free(histogram_image); + histogram_image = NULL; + + // Store actual literals. + StoreImageToBitMask(bw, width, histogram_bits, &refs, + histogram_symbols, huffman_codes); + ok = 1; + + Error: + if (!ok) free(histogram_image); + + VP8LClearBackwardRefs(&refs); + if (huffman_codes != NULL) { + free(huffman_codes->codes); + free(huffman_codes); + } + free(histogram_symbols); + return ok; +} + +// ----------------------------------------------------------------------------- +// Transforms + +// Check if it would be a good idea to subtract green from red and blue. We +// only impact entropy in red/blue components, don't bother to look at others. +static int EvalAndApplySubtractGreen(VP8LEncoder* const enc, + int width, int height, + VP8LBitWriter* const bw) { + if (!enc->use_palette_) { + int i; + const uint32_t* const argb = enc->argb_; + double bit_cost_before, bit_cost_after; + VP8LHistogram* const histo = (VP8LHistogram*)malloc(sizeof(*histo)); + if (histo == NULL) return 0; + + VP8LHistogramInit(histo, 1); + for (i = 0; i < width * height; ++i) { + const uint32_t c = argb[i]; + ++histo->red_[(c >> 16) & 0xff]; + ++histo->blue_[(c >> 0) & 0xff]; + } + bit_cost_before = VP8LHistogramEstimateBits(histo); + + VP8LHistogramInit(histo, 1); + for (i = 0; i < width * height; ++i) { + const uint32_t c = argb[i]; + const int green = (c >> 8) & 0xff; + ++histo->red_[((c >> 16) - green) & 0xff]; + ++histo->blue_[((c >> 0) - green) & 0xff]; + } + bit_cost_after = VP8LHistogramEstimateBits(histo); + free(histo); + + // Check if subtracting green yields low entropy. + enc->use_subtract_green_ = (bit_cost_after < bit_cost_before); + if (enc->use_subtract_green_) { + VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); + VP8LWriteBits(bw, 2, SUBTRACT_GREEN); + VP8LSubtractGreenFromBlueAndRed(enc->argb_, width * height); + } + } + return 1; +} + +static int ApplyPredictFilter(const VP8LEncoder* const enc, + int width, int height, int quality, + 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); + + VP8LResidualImage(width, height, pred_bits, enc->argb_, enc->argb_scratch_, + enc->transform_data_); + VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); + VP8LWriteBits(bw, 2, PREDICTOR_TRANSFORM); + assert(pred_bits >= 2); + VP8LWriteBits(bw, 3, pred_bits - 2); + if (!EncodeImageNoHuffman(bw, enc->transform_data_, + transform_width, transform_height, quality)) { + return 0; + } + return 1; +} + +static int 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); + const int step = (quality == 0) ? 32 : 8; + + VP8LColorSpaceTransform(width, height, ccolor_transform_bits, step, + enc->argb_, enc->transform_data_); + VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); + VP8LWriteBits(bw, 2, CROSS_COLOR_TRANSFORM); + assert(ccolor_transform_bits >= 2); + VP8LWriteBits(bw, 3, ccolor_transform_bits - 2); + if (!EncodeImageNoHuffman(bw, enc->transform_data_, + transform_width, transform_height, quality)) { + return 0; + } + return 1; +} + +// ----------------------------------------------------------------------------- + +static void PutLE32(uint8_t* const data, uint32_t val) { + data[0] = (val >> 0) & 0xff; + data[1] = (val >> 8) & 0xff; + data[2] = (val >> 16) & 0xff; + data[3] = (val >> 24) & 0xff; +} + +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); + + VP8LWriteBits(bw, VP8L_IMAGE_SIZE_BITS, width); + VP8LWriteBits(bw, VP8L_IMAGE_SIZE_BITS, height); + return !bw->error_; +} + +static int WriteRealAlphaAndVersion(VP8LBitWriter* const bw, int has_alpha) { + VP8LWriteBits(bw, 1, has_alpha); + VP8LWriteBits(bw, VP8L_VERSION_BITS, VP8L_VERSION); + 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; +} + +// ----------------------------------------------------------------------------- + +// Allocates the memory for argb (W x H) buffer, 2 rows of context for +// prediction and transform data. +static WebPEncodingError AllocateTransformBuffer(VP8LEncoder* const enc, + int width, int height) { + WebPEncodingError err = VP8_ENC_OK; + const int tile_size = 1 << enc->transform_bits_; + const uint64_t image_size = width * height; + const uint64_t argb_scratch_size = tile_size * width + width; + const uint64_t transform_data_size = + (uint64_t)VP8LSubSampleSize(width, enc->transform_bits_) * + (uint64_t)VP8LSubSampleSize(height, enc->transform_bits_); + const uint64_t total_size = + image_size + argb_scratch_size + transform_data_size; + uint32_t* mem = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*mem)); + if (mem == NULL) { + err = VP8_ENC_ERROR_OUT_OF_MEMORY; + goto Error; + } + enc->argb_ = mem; + mem += image_size; + enc->argb_scratch_ = mem; + mem += argb_scratch_size; + enc->transform_data_ = mem; + enc->current_width_ = width; + + Error: + return err; +} + +// Bundles multiple (2, 4 or 8) pixels into a single pixel. +// Returns the new xsize. +static void BundleColorMap(const WebPPicture* const pic, + int xbits, uint32_t* bundled_argb, int xs) { + int y; + const int bit_depth = 1 << (3 - xbits); + uint32_t code = 0; + const uint32_t* argb = pic->argb; + const int width = pic->width; + const int height = pic->height; + + for (y = 0; y < height; ++y) { + int x; + for (x = 0; x < width; ++x) { + const int mask = (1 << xbits) - 1; + const int xsub = x & mask; + if (xsub == 0) { + code = 0; + } + // TODO(vikasa): simplify the bundling logic. + code |= (argb[x] & 0xff00) << (bit_depth * xsub); + bundled_argb[y * xs + (x >> xbits)] = 0xff000000 | code; + } + argb += pic->argb_stride; + } +} + +// Note: Expects "enc->palette_" to be set properly. +// Also, "enc->palette_" will be modified after this call and should not be used +// later. +static WebPEncodingError ApplyPalette(VP8LBitWriter* const bw, + VP8LEncoder* const enc, int quality) { + WebPEncodingError err = VP8_ENC_OK; + int i, x, y; + const WebPPicture* const pic = enc->pic_; + uint32_t* argb = pic->argb; + const int width = pic->width; + const int height = pic->height; + uint32_t* const palette = enc->palette_; + const int palette_size = enc->palette_size_; + + // Replace each input pixel by corresponding palette index. + for (y = 0; y < height; ++y) { + for (x = 0; x < width; ++x) { + const uint32_t pix = argb[x]; + for (i = 0; i < palette_size; ++i) { + if (pix == palette[i]) { + argb[x] = 0xff000000u | (i << 8); + break; + } + } + } + argb += pic->argb_stride; + } + + // Save palette to bitstream. + VP8LWriteBits(bw, 1, TRANSFORM_PRESENT); + VP8LWriteBits(bw, 2, COLOR_INDEXING_TRANSFORM); + assert(palette_size >= 1); + VP8LWriteBits(bw, 8, palette_size - 1); + for (i = palette_size - 1; i >= 1; --i) { + palette[i] = VP8LSubPixels(palette[i], palette[i - 1]); + } + if (!EncodeImageNoHuffman(bw, palette, palette_size, 1, quality)) { + err = VP8_ENC_ERROR_INVALID_CONFIGURATION; + goto Error; + } + + if (palette_size <= 16) { + // Image can be packed (multiple pixels per uint32_t). + int xbits = 1; + if (palette_size <= 2) { + xbits = 3; + } else if (palette_size <= 4) { + xbits = 2; + } + err = AllocateTransformBuffer(enc, VP8LSubSampleSize(width, xbits), height); + if (err != VP8_ENC_OK) goto Error; + BundleColorMap(pic, xbits, enc->argb_, enc->current_width_); + } + + Error: + return err; +} + +// ----------------------------------------------------------------------------- + +static int GetHistoBits(const WebPConfig* const config, + const WebPPicture* const pic) { + const int width = pic->width; + const int height = pic->height; + const size_t hist_size = sizeof(VP8LHistogram); + // Make tile size a function of encoding method (Range: 0 to 6). + int histo_bits = 7 - config->method; + while (1) { + const size_t huff_image_size = VP8LSubSampleSize(width, histo_bits) * + VP8LSubSampleSize(height, histo_bits) * + hist_size; + 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 void InitEncParams(VP8LEncoder* const enc) { + const WebPConfig* const config = enc->config_; + const WebPPicture* const picture = enc->pic_; + const int method = config->method; + const float quality = config->quality; + enc->transform_bits_ = (method < 4) ? 5 : (method > 4) ? 3 : 4; + enc->histo_bits_ = GetHistoBits(config, picture); + enc->cache_bits_ = (quality <= 25.f) ? 0 : 7; +} + +// ----------------------------------------------------------------------------- +// VP8LEncoder + +static VP8LEncoder* VP8LEncoderNew(const WebPConfig* const config, + const WebPPicture* const picture) { + VP8LEncoder* const enc = (VP8LEncoder*)calloc(1, sizeof(*enc)); + if (enc == NULL) { + WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY); + return NULL; + } + enc->config_ = config; + enc->pic_ = picture; + return enc; +} + +static void VP8LEncoderDelete(VP8LEncoder* enc) { + free(enc->argb_); + free(enc); +} + +// ----------------------------------------------------------------------------- +// Main call + +WebPEncodingError VP8LEncodeStream(const WebPConfig* const config, + const WebPPicture* const picture, + VP8LBitWriter* const bw) { + WebPEncodingError err = VP8_ENC_OK; + const int quality = (int)config->quality; + const int width = picture->width; + const int height = picture->height; + VP8LEncoder* const enc = VP8LEncoderNew(config, picture); + const size_t byte_position = VP8LBitWriterNumBytes(bw); + + if (enc == NULL) { + err = VP8_ENC_ERROR_OUT_OF_MEMORY; + goto Error; + } + + InitEncParams(enc); + + // --------------------------------------------------------------------------- + // Analyze image (entropy, num_palettes etc) + + if (!VP8LEncAnalyze(enc, config->image_hint)) { + err = VP8_ENC_ERROR_OUT_OF_MEMORY; + goto Error; + } + + if (enc->use_palette_) { + err = ApplyPalette(bw, enc, quality); + if (err != VP8_ENC_OK) goto Error; + // Color cache is disabled for palette. + enc->cache_bits_ = 0; + } + + // In case image is not packed. + if (enc->argb_ == NULL) { + int y; + err = AllocateTransformBuffer(enc, width, height); + if (err != VP8_ENC_OK) goto Error; + for (y = 0; y < height; ++y) { + memcpy(enc->argb_ + y * width, + picture->argb + y * picture->argb_stride, + width * sizeof(*enc->argb_)); + } + enc->current_width_ = width; + } + + // --------------------------------------------------------------------------- + // Apply transforms and write transform data. + + if (!EvalAndApplySubtractGreen(enc, enc->current_width_, height, bw)) { + err = VP8_ENC_ERROR_OUT_OF_MEMORY; + goto Error; + } + + if (enc->use_predict_) { + if (!ApplyPredictFilter(enc, enc->current_width_, height, quality, bw)) { + err = VP8_ENC_ERROR_INVALID_CONFIGURATION; + goto Error; + } + } + + if (enc->use_cross_color_) { + if (!ApplyCrossColorFilter(enc, enc->current_width_, height, quality, bw)) { + err = VP8_ENC_ERROR_INVALID_CONFIGURATION; + goto Error; + } + } + + VP8LWriteBits(bw, 1, !TRANSFORM_PRESENT); // No more transforms. + + // --------------------------------------------------------------------------- + // Estimate the color cache size. + + if (enc->cache_bits_ > 0) { + if (!VP8LCalculateEstimateForCacheSize(enc->argb_, enc->current_width_, + height, &enc->cache_bits_)) { + err = VP8_ENC_ERROR_INVALID_CONFIGURATION; + goto Error; + } + } + + // --------------------------------------------------------------------------- + // Encode and write the transformed image. + + if (!EncodeImageInternal(bw, enc->argb_, enc->current_width_, height, + quality, enc->cache_bits_, enc->histo_bits_)) { + err = VP8_ENC_ERROR_OUT_OF_MEMORY; + 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); + } + + 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; + 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; + if (!VP8LBitWriterInit(&bw, (width * height) >> 1)) { + 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); + 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; + VP8LBitWriterDestroy(&bw); + if (err != VP8_ENC_OK) { + WebPEncodingSetError(picture, err); + return 0; + } + return 1; +} + +//------------------------------------------------------------------------------ + +#if defined(__cplusplus) || defined(c_plusplus) +} // extern "C" +#endif |