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Add VP8L prefix to backward ref & histogram methods.

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Change-Id: I8c14fb219a1d7830d3244aa780c91c9964867330
This commit is contained in:
Vikas Arora
2012-04-10 03:56:07 +00:00
committed by James Zern
parent fcba7be2d3
commit 32714ce3be
4 changed files with 147 additions and 154 deletions
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98
src/enc/backward_references.c
View File

@@ -32,7 +32,7 @@ static const uint8_t plane_to_code_lut[128] = {
static const int kMinLength = 2; static const int kMinLength = 2;
int DistanceToPlaneCode(int xsize, int dist) { int VP8LDistanceToPlaneCode(int xsize, int dist) {
int yoffset = dist / xsize; int yoffset = dist / xsize;
int xoffset = dist - yoffset * xsize; int xoffset = dist - yoffset * xsize;
if (xoffset <= 8 && yoffset < 8) { if (xoffset <= 8 && yoffset < 8) {
@@ -193,8 +193,8 @@ static WEBP_INLINE void PushBackCopy(int length,
} }
} }
void BackwardReferencesRle(int xsize, int ysize, const uint32_t* argb, void VP8LBackwardReferencesRle(int xsize, int ysize, const uint32_t* argb,
PixOrCopy* stream, int* stream_size) { PixOrCopy* stream, int* stream_size) {
const int pix_count = xsize * ysize; const int pix_count = xsize * ysize;
int streak = 0; int streak = 0;
int i; int i;
@@ -213,10 +213,10 @@ void BackwardReferencesRle(int xsize, int ysize, const uint32_t* argb,
} }
// Returns 1 when successful. // Returns 1 when successful.
int BackwardReferencesHashChain(int xsize, int ysize, int use_palette, int VP8LBackwardReferencesHashChain(int xsize, int ysize, int use_palette,
const uint32_t* argb, int palette_bits, const uint32_t* argb, int palette_bits,
int quality, int quality, PixOrCopy* stream,
PixOrCopy* stream, int* stream_size) { int* stream_size) {
const int pix_count = xsize * ysize; const int pix_count = xsize * ysize;
int i; int i;
int ok = 0; int ok = 0;
@@ -320,7 +320,7 @@ static int CostModel_Build(CostModel* p, int xsize, int ysize,
const uint32_t* argb, int palette_bits) { const uint32_t* argb, int palette_bits) {
int ok = 0; int ok = 0;
int stream_size; int stream_size;
Histogram histo; VP8LHistogram histo;
int i; int i;
PixOrCopy* stream = (PixOrCopy*)malloc(xsize * ysize * sizeof(*stream)); PixOrCopy* stream = (PixOrCopy*)malloc(xsize * ysize * sizeof(*stream));
if (stream == NULL) { if (stream == NULL) {
@@ -328,34 +328,33 @@ static int CostModel_Build(CostModel* p, int xsize, int ysize,
} }
p->palette_bits_ = palette_bits; p->palette_bits_ = palette_bits;
if (recursion_level > 0) { if (recursion_level > 0) {
if (!BackwardReferencesTraceBackwards(xsize, ysize, recursion_level - 1, if (!VP8LBackwardReferencesTraceBackwards(xsize, ysize, recursion_level - 1,
use_palette, argb, use_palette, argb, palette_bits,
palette_bits, &stream[0], &stream_size)) {
&stream[0], &stream_size)) {
goto Error; goto Error;
} }
} else { } else {
const int quality = 100; const int quality = 100;
if (!BackwardReferencesHashChain(xsize, ysize, use_palette, argb, if (!VP8LBackwardReferencesHashChain(xsize, ysize, use_palette, argb,
palette_bits, quality, palette_bits, quality,
&stream[0], &stream_size)) { &stream[0], &stream_size)) {
goto Error; goto Error;
} }
} }
HistogramInit(&histo, palette_bits); VP8LHistogramInit(&histo, palette_bits);
for (i = 0; i < stream_size; ++i) { for (i = 0; i < stream_size; ++i) {
HistogramAddSinglePixOrCopy(&histo, stream[i]); VP8LHistogramAddSinglePixOrCopy(&histo, stream[i]);
} }
ConvertPopulationCountTableToBitEstimates( VP8LConvertPopulationCountTableToBitEstimates(
HistogramNumPixOrCopyCodes(&histo), VP8LHistogramNumCodes(&histo),
&histo.literal_[0], &p->literal_[0]); &histo.literal_[0], &p->literal_[0]);
ConvertPopulationCountTableToBitEstimates( VP8LConvertPopulationCountTableToBitEstimates(
VALUES_IN_BYTE, &histo.red_[0], &p->red_[0]); VALUES_IN_BYTE, &histo.red_[0], &p->red_[0]);
ConvertPopulationCountTableToBitEstimates( VP8LConvertPopulationCountTableToBitEstimates(
VALUES_IN_BYTE, &histo.blue_[0], &p->blue_[0]); VALUES_IN_BYTE, &histo.blue_[0], &p->blue_[0]);
ConvertPopulationCountTableToBitEstimates( VP8LConvertPopulationCountTableToBitEstimates(
VALUES_IN_BYTE, &histo.alpha_[0], &p->alpha_[0]); VALUES_IN_BYTE, &histo.alpha_[0], &p->alpha_[0]);
ConvertPopulationCountTableToBitEstimates( VP8LConvertPopulationCountTableToBitEstimates(
DISTANCE_CODES_MAX, &histo.distance_[0], &p->distance_[0]); DISTANCE_CODES_MAX, &histo.distance_[0], &p->distance_[0]);
ok = 1; ok = 1;
Error: Error:
@@ -440,7 +439,7 @@ static int BackwardReferencesHashChainDistanceOnly(
&offset, &len); &offset, &len);
} }
if (len >= kMinLength) { if (len >= kMinLength) {
const int code = DistanceToPlaneCode(xsize, offset); const int code = VP8LDistanceToPlaneCode(xsize, offset);
const double distance_cost = const double distance_cost =
prev_cost + CostModel_DistanceCost(cost_model, code); prev_cost + CostModel_DistanceCost(cost_model, code);
int k; int k;
@@ -601,13 +600,13 @@ Error:
} }
// Returns 1 on success. // Returns 1 on success.
int BackwardReferencesTraceBackwards(int xsize, int ysize, int VP8LBackwardReferencesTraceBackwards(int xsize, int ysize,
int recursive_cost_model, int recursive_cost_model,
int use_palette, int use_palette,
const uint32_t* argb, const uint32_t* argb,
int palette_bits, int palette_bits,
PixOrCopy* stream, PixOrCopy* stream,
int* stream_size) { int* stream_size) {
int ok = 0; int ok = 0;
const int dist_array_size = xsize * ysize; const int dist_array_size = xsize * ysize;
uint32_t* chosen_path = NULL; uint32_t* chosen_path = NULL;
@@ -638,21 +637,22 @@ Error:
return ok; return ok;
} }
void BackwardReferences2DLocality(int xsize, int data_size, PixOrCopy* data) { void VP8LBackwardReferences2DLocality(int xsize, int data_size,
PixOrCopy* data) {
int i; int i;
for (i = 0; i < data_size; ++i) { for (i = 0; i < data_size; ++i) {
if (PixOrCopyIsCopy(&data[i])) { if (PixOrCopyIsCopy(&data[i])) {
int dist = data[i].argb_or_offset; int dist = data[i].argb_or_offset;
int transformed_dist = DistanceToPlaneCode(xsize, dist); int transformed_dist = VP8LDistanceToPlaneCode(xsize, dist);
data[i].argb_or_offset = transformed_dist; data[i].argb_or_offset = transformed_dist;
} }
} }
} }
int VerifyBackwardReferences(const uint32_t* argb, int xsize, int ysize, int VP8LVerifyBackwardReferences(const uint32_t* argb, int xsize, int ysize,
int palette_bits, int palette_bits,
const PixOrCopy* lit, const PixOrCopy* lit,
int lit_size) { int lit_size) {
int num_pixels = 0; int num_pixels = 0;
int i; int i;
VP8LColorCache hashers; VP8LColorCache hashers;
@@ -717,7 +717,7 @@ int VerifyBackwardReferences(const uint32_t* argb, int xsize, int ysize,
// Returns 1 on success. // Returns 1 on success.
static int ComputePaletteHistogram(const uint32_t* argb, int xsize, int ysize, static int ComputePaletteHistogram(const uint32_t* argb, int xsize, int ysize,
PixOrCopy* stream, int stream_size, PixOrCopy* stream, int stream_size,
int palette_bits, Histogram* histo) { int palette_bits, VP8LHistogram* histo) {
int pixel_index = 0; int pixel_index = 0;
int i; int i;
uint32_t k; uint32_t k;
@@ -732,12 +732,12 @@ static int ComputePaletteHistogram(const uint32_t* argb, int xsize, int ysize,
VP8LColorCacheContains(&hashers, argb[pixel_index])) { VP8LColorCacheContains(&hashers, argb[pixel_index])) {
// push pixel as a palette pixel // push pixel as a palette pixel
const int ix = VP8LColorCacheGetIndex(&hashers, argb[pixel_index]); const int ix = VP8LColorCacheGetIndex(&hashers, argb[pixel_index]);
HistogramAddSinglePixOrCopy(histo, PixOrCopyCreatePaletteIx(ix)); VP8LHistogramAddSinglePixOrCopy(histo, PixOrCopyCreatePaletteIx(ix));
} else { } else {
HistogramAddSinglePixOrCopy(histo, v); VP8LHistogramAddSinglePixOrCopy(histo, v);
} }
} else { } else {
HistogramAddSinglePixOrCopy(histo, v); VP8LHistogramAddSinglePixOrCopy(histo, v);
} }
for (k = 0; k < PixOrCopyLength(&v); ++k) { for (k = 0; k < PixOrCopyLength(&v); ++k) {
VP8LColorCacheInsert(&hashers, argb[pixel_index]); VP8LColorCacheInsert(&hashers, argb[pixel_index]);
@@ -752,9 +752,9 @@ static int ComputePaletteHistogram(const uint32_t* argb, int xsize, int ysize,
} }
// Returns how many bits are to be used for a palette. // Returns how many bits are to be used for a palette.
int CalculateEstimateForPaletteSize(const uint32_t* argb, int VP8LCalculateEstimateForPaletteSize(const uint32_t* argb,
int xsize, int ysize, int xsize, int ysize,
int* best_palette_bits) { int* best_palette_bits) {
int ok = 0; int ok = 0;
int palette_bits; int palette_bits;
double lowest_entropy = 1e99; double lowest_entropy = 1e99;
@@ -763,17 +763,17 @@ int CalculateEstimateForPaletteSize(const uint32_t* argb,
static const double kSmallPenaltyForLargePalette = 4.0; static const double kSmallPenaltyForLargePalette = 4.0;
static const int quality = 30; static const int quality = 30;
if (stream == NULL || if (stream == NULL ||
!BackwardReferencesHashChain(xsize, ysize, !VP8LBackwardReferencesHashChain(xsize, ysize, 0, argb, 0, quality,
0, argb, 0, quality, stream, &stream_size)) { stream, &stream_size)) {
goto Error; goto Error;
} }
for (palette_bits = 0; palette_bits < 12; ++palette_bits) { for (palette_bits = 0; palette_bits < 12; ++palette_bits) {
double cur_entropy; double cur_entropy;
Histogram histo; VP8LHistogram histo;
HistogramInit(&histo, palette_bits); VP8LHistogramInit(&histo, palette_bits);
ComputePaletteHistogram(argb, xsize, ysize, &stream[0], stream_size, ComputePaletteHistogram(argb, xsize, ysize, &stream[0], stream_size,
palette_bits, &histo); palette_bits, &histo);
cur_entropy = HistogramEstimateBits(&histo) + cur_entropy = VP8LHistogramEstimateBits(&histo) +
kSmallPenaltyForLargePalette * palette_bits; kSmallPenaltyForLargePalette * palette_bits;
if (palette_bits == 0 || cur_entropy < lowest_entropy) { if (palette_bits == 0 || cur_entropy < lowest_entropy) {
*best_palette_bits = palette_bits; *best_palette_bits = palette_bits;

28
src/enc/backward_references.h
View File

@@ -173,7 +173,7 @@ static WEBP_INLINE void PixOrCopyLengthCodeAndBits(
// Ridiculously simple backward references for images where it is unlikely // Ridiculously simple backward references for images where it is unlikely
// that there are large backward references (photos). // that there are large backward references (photos).
void BackwardReferencesRle( void VP8LBackwardReferencesRle(
int xsize, int xsize,
int ysize, int ysize,
const uint32_t *argb, const uint32_t *argb,
@@ -182,7 +182,7 @@ void BackwardReferencesRle(
// This is a simple fast function for obtaining backward references // This is a simple fast function for obtaining backward references
// based on simple heuristics. Returns 1 on success. // based on simple heuristics. Returns 1 on success.
int BackwardReferencesHashChain( int VP8LBackwardReferencesHashChain(
int xsize, int xsize,
int ysize, int ysize,
int use_palette, int use_palette,
@@ -195,7 +195,7 @@ int BackwardReferencesHashChain(
// This method looks for a shortest path through the backward reference // This method looks for a shortest path through the backward reference
// network based on a cost model generated by a first round of compression. // network based on a cost model generated by a first round of compression.
// Returns 1 on success. // Returns 1 on success.
int BackwardReferencesTraceBackwards( int VP8LBackwardReferencesTraceBackwards(
int xsize, int xsize,
int ysize, int ysize,
int recursive_cost_model, int recursive_cost_model,
@@ -208,24 +208,24 @@ int BackwardReferencesTraceBackwards(
// Convert backward references that are of linear distance along // Convert backward references that are of linear distance along
// the image scan lines to have a 2d locality indexing where // the image scan lines to have a 2d locality indexing where
// smaller values are used for backward references that are close by. // smaller values are used for backward references that are close by.
void BackwardReferences2DLocality(int xsize, int data_size, void VP8LBackwardReferences2DLocality(int xsize, int data_size,
PixOrCopy *data); PixOrCopy *data);
// Internals of locality transform exposed for testing use. // Internals of locality transform exposed for testing use.
int DistanceToPlaneCode(int xsize, int distance); int VP8LDistanceToPlaneCode(int xsize, int distance);
// Returns true if the given backward references actually produce // Returns true if the given backward references actually produce
// the image given in tuple (argb, xsize, ysize). // the image given in tuple (argb, xsize, ysize).
int VerifyBackwardReferences(const uint32_t* argb, int VP8LVerifyBackwardReferences(const uint32_t* argb,
int xsize, int ysize, int xsize, int ysize,
int palette_bits, int palette_bits,
const PixOrCopy *lit, const PixOrCopy *lit,
int lit_size); int lit_size);
// Produce an estimate for a good emerging palette size for the image. // Produce an estimate for a good emerging palette size for the image.
int CalculateEstimateForPaletteSize(const uint32_t *argb, int VP8LCalculateEstimateForPaletteSize(const uint32_t *argb,
int xsize, int ysize, int xsize, int ysize,
int *best_palette_bits); int *best_palette_bits);
#if defined(__cplusplus) || defined(c_plusplus) #if defined(__cplusplus) || defined(c_plusplus)
} }

106
src/enc/histogram.c
View File

@@ -116,7 +116,7 @@ static WEBP_INLINE double FastLog(int v) {
return log(v); return log(v);
} }
void ConvertPopulationCountTableToBitEstimates( void VP8LConvertPopulationCountTableToBitEstimates(
int num_symbols, int num_symbols,
const int* const population_counts, const int* const population_counts,
double* const output) { double* const output) {
@@ -145,7 +145,8 @@ void ConvertPopulationCountTableToBitEstimates(
} }
} }
void HistogramAddSinglePixOrCopy(Histogram* const p, const PixOrCopy v) { void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const p,
const PixOrCopy v) {
if (PixOrCopyIsLiteral(&v)) { if (PixOrCopyIsLiteral(&v)) {
++p->alpha_[PixOrCopyLiteral(&v, 3)]; ++p->alpha_[PixOrCopyLiteral(&v, 3)];
++p->red_[PixOrCopyLiteral(&v, 2)]; ++p->red_[PixOrCopyLiteral(&v, 2)];
@@ -165,17 +166,17 @@ void HistogramAddSinglePixOrCopy(Histogram* const p, const PixOrCopy v) {
} }
} }
void HistogramBuild(Histogram* const p, void VP8LHistogramCreate(VP8LHistogram* const p,
const PixOrCopy* const literal_and_length, const PixOrCopy* const literal_and_length,
int n_literal_and_length) { int n_literal_and_length) {
int i; int i;
HistogramClear(p); VP8LHistogramClear(p);
for (i = 0; i < n_literal_and_length; ++i) { for (i = 0; i < n_literal_and_length; ++i) {
HistogramAddSinglePixOrCopy(p, literal_and_length[i]); VP8LHistogramAddSinglePixOrCopy(p, literal_and_length[i]);
} }
} }
double ShannonEntropy(const int* const array, int n) { double VP8LShannonEntropy(const int* const array, int n) {
int i; int i;
double retval = 0; double retval = 0;
int sum = 0; int sum = 0;
@@ -208,7 +209,7 @@ static double BitsEntropy(const int* const array, int n) {
} }
} }
retval -= sum * FastLog(sum); retval -= sum * FastLog(sum);
retval *= -1.4426950408889634; // 1.0 / -FastLog(2); retval *= -1.4426950408889634; // 1.0 / -Log(2);
mix = 0.627; mix = 0.627;
if (nonzeros < 5) { if (nonzeros < 5) {
if (nonzeros <= 1) { if (nonzeros <= 1) {
@@ -240,8 +241,8 @@ static double BitsEntropy(const int* const array, int n) {
return retval; return retval;
} }
double HistogramEstimateBitsBulk(const Histogram* const p) { double VP8LHistogramEstimateBitsBulk(const VP8LHistogram* const p) {
double retval = BitsEntropy(&p->literal_[0], HistogramNumPixOrCopyCodes(p)) + double retval = BitsEntropy(&p->literal_[0], VP8LHistogramNumCodes(p)) +
BitsEntropy(&p->red_[0], 256) + BitsEntropy(&p->red_[0], 256) +
BitsEntropy(&p->blue_[0], 256) + BitsEntropy(&p->blue_[0], 256) +
BitsEntropy(&p->alpha_[0], 256) + BitsEntropy(&p->alpha_[0], 256) +
@@ -258,8 +259,8 @@ double HistogramEstimateBitsBulk(const Histogram* const p) {
return retval; return retval;
} }
double HistogramEstimateBits(const Histogram* const p) { double VP8LHistogramEstimateBits(const VP8LHistogram* const p) {
return HistogramEstimateBitsHeader(p) + HistogramEstimateBitsBulk(p); return VP8LHistogramEstimateBitsHeader(p) + VP8LHistogramEstimateBitsBulk(p);
} }
// Returns the cost encode the rle-encoded entropy code. // Returns the cost encode the rle-encoded entropy code.
@@ -301,35 +302,33 @@ static double HuffmanCost(const int* const population, int length) {
return retval; return retval;
} }
double HistogramEstimateBitsHeader(const Histogram* const p) { double VP8LHistogramEstimateBitsHeader(const VP8LHistogram* const p) {
return HuffmanCost(&p->alpha_[0], 256) + return HuffmanCost(&p->alpha_[0], 256) +
HuffmanCost(&p->red_[0], 256) + HuffmanCost(&p->red_[0], 256) +
HuffmanCost(&p->literal_[0], HistogramNumPixOrCopyCodes(p)) + HuffmanCost(&p->literal_[0], VP8LHistogramNumCodes(p)) +
HuffmanCost(&p->blue_[0], 256) + HuffmanCost(&p->blue_[0], 256) +
HuffmanCost(&p->distance_[0], DISTANCE_CODES_MAX); HuffmanCost(&p->distance_[0], DISTANCE_CODES_MAX);
} }
int BuildHistogramImage(int xsize, int ysize, int VP8LHistogramBuildImage(int xsize, int ysize,
int histobits, int histobits, int palettebits,
int palettebits, const PixOrCopy* backward_refs,
const PixOrCopy* backward_refs, int backward_refs_size,
int backward_refs_size, VP8LHistogram*** image_arg, int* image_size) {
Histogram*** image_arg,
int* image_size) {
int histo_xsize = histobits ? (xsize + (1 << histobits) - 1) >> histobits : 1; int histo_xsize = histobits ? (xsize + (1 << histobits) - 1) >> histobits : 1;
int histo_ysize = histobits ? (ysize + (1 << histobits) - 1) >> histobits : 1; int histo_ysize = histobits ? (ysize + (1 << histobits) - 1) >> histobits : 1;
int i; int i;
int x = 0; int x = 0;
int y = 0; int y = 0;
Histogram** image; VP8LHistogram** image;
*image_arg = NULL; *image_arg = NULL;
*image_size = histo_xsize * histo_ysize; *image_size = histo_xsize * histo_ysize;
image = (Histogram**)calloc(*image_size, sizeof(*image)); image = (VP8LHistogram**)calloc(*image_size, sizeof(*image));
if (image == NULL) { if (image == NULL) {
return 0; return 0;
} }
for (i = 0; i < *image_size; ++i) { for (i = 0; i < *image_size; ++i) {
image[i] = (Histogram*)malloc(sizeof(*image[i])); image[i] = (VP8LHistogram*)malloc(sizeof(*image[i]));
if (!image[i]) { if (!image[i]) {
int k; int k;
for (k = 0; k < *image_size; ++k) { for (k = 0; k < *image_size; ++k) {
@@ -338,14 +337,14 @@ int BuildHistogramImage(int xsize, int ysize,
free(image); free(image);
return 0; return 0;
} }
HistogramInit(image[i], palettebits); VP8LHistogramInit(image[i], palettebits);
} }
// x and y trace the position in the image. // x and y trace the position in the image.
for (i = 0; i < backward_refs_size; ++i) { for (i = 0; i < backward_refs_size; ++i) {
const PixOrCopy v = backward_refs[i]; const PixOrCopy v = backward_refs[i];
const int ix = const int ix =
histobits ? (y >> histobits) * histo_xsize + (x >> histobits) : 0; histobits ? (y >> histobits) * histo_xsize + (x >> histobits) : 0;
HistogramAddSinglePixOrCopy(image[ix], v); VP8LHistogramAddSinglePixOrCopy(image[ix], v);
x += PixOrCopyLength(&v); x += PixOrCopyLength(&v);
while (x >= xsize) { while (x >= xsize) {
x -= xsize; x -= xsize;
@@ -356,11 +355,8 @@ int BuildHistogramImage(int xsize, int ysize,
return 1; return 1;
} }
int CombineHistogramImage(Histogram** in, int VP8LHistogramCombine(VP8LHistogram** in, int in_size, int quality,
int in_size, VP8LHistogram*** out_arg, int* out_size) {
int quality,
Histogram*** out_arg,
int* out_size) {
int ok = 0; int ok = 0;
int i; int i;
unsigned int seed = 0; unsigned int seed = 0;
@@ -368,7 +364,7 @@ int CombineHistogramImage(Histogram** in,
int inner_iters = 10 + quality / 2; int inner_iters = 10 + quality / 2;
int iter; int iter;
double* bit_costs = (double*)malloc(in_size * sizeof(*bit_costs)); double* bit_costs = (double*)malloc(in_size * sizeof(*bit_costs));
Histogram** out = (Histogram**)calloc(in_size, sizeof(*out)); VP8LHistogram** out = (VP8LHistogram**)calloc(in_size, sizeof(*out));
*out_arg = out; *out_arg = out;
*out_size = in_size; *out_size = in_size;
if (bit_costs == NULL || out == NULL) { if (bit_costs == NULL || out == NULL) {
@@ -376,13 +372,13 @@ int CombineHistogramImage(Histogram** in,
} }
// Copy // Copy
for (i = 0; i < in_size; ++i) { for (i = 0; i < in_size; ++i) {
Histogram* new_histo = (Histogram*)malloc(sizeof(*new_histo)); VP8LHistogram* new_histo = (VP8LHistogram*)malloc(sizeof(*new_histo));
if (new_histo == NULL) { if (new_histo == NULL) {
goto Error; goto Error;
} }
*new_histo = *(in[i]); *new_histo = *(in[i]);
out[i] = new_histo; out[i] = new_histo;
bit_costs[i] = HistogramEstimateBits(out[i]); bit_costs[i] = VP8LHistogramEstimateBits(out[i]);
} }
// Collapse similar histograms. // Collapse similar histograms.
for (iter = 0; iter < in_size * 3 && *out_size >= 2; ++iter) { for (iter = 0; iter < in_size * 3 && *out_size >= 2; ++iter) {
@@ -394,7 +390,7 @@ int CombineHistogramImage(Histogram** in,
for (k = 0; k < inner_iters; ++k) { for (k = 0; k < inner_iters; ++k) {
// Choose two, build a combo out of them. // Choose two, build a combo out of them.
double cost_val; double cost_val;
Histogram* combo; VP8LHistogram* combo;
int ix0 = rand_r(&seed) % *out_size; int ix0 = rand_r(&seed) % *out_size;
int ix1; int ix1;
int diff = ((k & 7) + 1) % (*out_size - 1); int diff = ((k & 7) + 1) % (*out_size - 1);
@@ -405,13 +401,14 @@ int CombineHistogramImage(Histogram** in,
if (ix0 == ix1) { if (ix0 == ix1) {
continue; continue;
} }
combo = (Histogram*)malloc(sizeof(*combo)); combo = (VP8LHistogram*)malloc(sizeof(*combo));
if (combo == NULL) { if (combo == NULL) {
goto Error; goto Error;
} }
*combo = *out[ix0]; *combo = *out[ix0];
HistogramAdd(combo, out[ix1]); VP8LHistogramAdd(combo, out[ix1]);
cost_val = HistogramEstimateBits(combo) - bit_costs[ix0] - bit_costs[ix1]; cost_val =
VP8LHistogramEstimateBits(combo) - bit_costs[ix0] - bit_costs[ix1];
if (best_val > cost_val) { if (best_val > cost_val) {
best_val = cost_val; best_val = cost_val;
best_ix0 = ix0; best_ix0 = ix0;
@@ -420,7 +417,7 @@ int CombineHistogramImage(Histogram** in,
free(combo); free(combo);
} }
if (best_val < 0.0) { if (best_val < 0.0) {
HistogramAdd(out[best_ix0], out[best_ix1]); VP8LHistogramAdd(out[best_ix0], out[best_ix1]);
bit_costs[best_ix0] = bit_costs[best_ix0] =
best_val + bit_costs[best_ix0] + bit_costs[best_ix1]; best_val + bit_costs[best_ix0] + bit_costs[best_ix1];
// Erase (*out)[best_ix1] // Erase (*out)[best_ix1]
@@ -453,42 +450,39 @@ Error:
// What is the bit cost of moving square_histogram from // What is the bit cost of moving square_histogram from
// cur_symbol to candidate_symbol. // cur_symbol to candidate_symbol.
static double HistogramDistance(const Histogram* const square_histogram, static double HistogramDistance(const VP8LHistogram* const square_histogram,
int cur_symbol, int cur_symbol,
int candidate_symbol, int candidate_symbol,
Histogram** candidate_histograms) { VP8LHistogram** candidate_histograms) {
double new_bit_cost; double new_bit_cost;
double previous_bit_cost; double previous_bit_cost;
Histogram modified; VP8LHistogram modified;
if (cur_symbol == candidate_symbol) { if (cur_symbol == candidate_symbol) {
return 0; // Going nowhere. No savings. return 0; // Going nowhere. No savings.
} }
previous_bit_cost = previous_bit_cost =
HistogramEstimateBits(candidate_histograms[candidate_symbol]); VP8LHistogramEstimateBits(candidate_histograms[candidate_symbol]);
if (cur_symbol != -1) { if (cur_symbol != -1) {
previous_bit_cost += previous_bit_cost +=
HistogramEstimateBits(candidate_histograms[cur_symbol]); VP8LHistogramEstimateBits(candidate_histograms[cur_symbol]);
} }
// Compute the bit cost of the histogram where the data moves to. // Compute the bit cost of the histogram where the data moves to.
modified = *candidate_histograms[candidate_symbol]; modified = *candidate_histograms[candidate_symbol];
HistogramAdd(&modified, square_histogram); VP8LHistogramAdd(&modified, square_histogram);
new_bit_cost = HistogramEstimateBits(&modified); new_bit_cost = VP8LHistogramEstimateBits(&modified);
// Compute the bit cost of the histogram where the data moves away. // Compute the bit cost of the histogram where the data moves away.
if (cur_symbol != -1) { if (cur_symbol != -1) {
modified = *candidate_histograms[cur_symbol]; modified = *candidate_histograms[cur_symbol];
HistogramRemove(&modified, square_histogram); VP8LHistogramRemove(&modified, square_histogram);
new_bit_cost += HistogramEstimateBits(&modified); new_bit_cost += VP8LHistogramEstimateBits(&modified);
} }
return new_bit_cost - previous_bit_cost; return new_bit_cost - previous_bit_cost;
} }
void RefineHistogramImage(Histogram** raw, void VP8LHistogramRefine(VP8LHistogram** raw, int raw_size,
int raw_size, uint32_t* symbols, int out_size, VP8LHistogram** out) {
uint32_t* symbols,
int out_size,
Histogram** out) {
int i; int i;
// Find the best 'out' histogram for each of the raw histograms // Find the best 'out' histogram for each of the raw histograms
for (i = 0; i < raw_size; ++i) { for (i = 0; i < raw_size; ++i) {
@@ -507,9 +501,9 @@ void RefineHistogramImage(Histogram** raw,
// Recompute each out based on raw and symbols. // Recompute each out based on raw and symbols.
for (i = 0; i < out_size; ++i) { for (i = 0; i < out_size; ++i) {
HistogramClear(out[i]); VP8LHistogramClear(out[i]);
} }
for (i = 0; i < raw_size; ++i) { for (i = 0; i < raw_size; ++i) {
HistogramAdd(out[symbols[i]], raw[i]); VP8LHistogramAdd(out[symbols[i]], raw[i]);
} }
} }

69
src/enc/histogram.h
View File

@@ -36,9 +36,9 @@ typedef struct {
// Backward reference prefix-code histogram. // Backward reference prefix-code histogram.
int distance_[DISTANCE_CODES_MAX]; int distance_[DISTANCE_CODES_MAX];
int palette_code_bits_; int palette_code_bits_;
} Histogram; } VP8LHistogram;
static WEBP_INLINE void HistogramClear(Histogram* const p) { static WEBP_INLINE void VP8LHistogramClear(VP8LHistogram* const p) {
memset(&p->literal_[0], 0, sizeof(p->literal_)); memset(&p->literal_[0], 0, sizeof(p->literal_));
memset(&p->red_[0], 0, sizeof(p->red_)); memset(&p->red_[0], 0, sizeof(p->red_));
memset(&p->blue_[0], 0, sizeof(p->blue_)); memset(&p->blue_[0], 0, sizeof(p->blue_));
@@ -46,36 +46,36 @@ static WEBP_INLINE void HistogramClear(Histogram* const p) {
memset(&p->distance_[0], 0, sizeof(p->distance_)); memset(&p->distance_[0], 0, sizeof(p->distance_));
} }
static WEBP_INLINE void HistogramInit(Histogram* const p, static WEBP_INLINE void VP8LHistogramInit(VP8LHistogram* const p,
int palette_code_bits) { int palette_code_bits) {
p->palette_code_bits_ = palette_code_bits; p->palette_code_bits_ = palette_code_bits;
HistogramClear(p); VP8LHistogramClear(p);
} }
// Create the histogram. // Create the histogram.
// //
// The input data is the PixOrCopy data, which models the // The input data is the PixOrCopy data, which models the
// literals, stop codes and backward references (both distances and lengths) // literals, stop codes and backward references (both distances and lengths)
void HistogramBuild(Histogram* const p, void VP8LHistogramCreate(VP8LHistogram* const p,
const PixOrCopy* const literal_and_length, const PixOrCopy* const literal_and_length,
int n_literal_and_length); int n_literal_and_length);
void HistogramAddSinglePixOrCopy(Histogram* const p, const PixOrCopy v); void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const p, const PixOrCopy v);
// Estimate how many bits the combined entropy of literals and distance // Estimate how many bits the combined entropy of literals and distance
// approximately maps to. // approximately maps to.
double HistogramEstimateBits(const Histogram* const p); double VP8LHistogramEstimateBits(const VP8LHistogram* const p);
// This function estimates the Huffman dictionary + other block overhead // This function estimates the Huffman dictionary + other block overhead
// size for creating a new deflate block. // size for creating a new deflate block.
double HistogramEstimateBitsHeader(const Histogram* const p); double VP8LHistogramEstimateBitsHeader(const VP8LHistogram* const p);
// This function estimates the cost in bits excluding the bits needed to // This function estimates the cost in bits excluding the bits needed to
// represent the entropy code itself. // represent the entropy code itself.
double HistogramEstimateBitsBulk(const Histogram* const p); double VP8LHistogramEstimateBitsBulk(const VP8LHistogram* const p);
static WEBP_INLINE void HistogramAdd(Histogram* const p, static WEBP_INLINE void VP8LHistogramAdd(VP8LHistogram* const p,
const Histogram* const a) { const VP8LHistogram* const a) {
int i; int i;
for (i = 0; i < PIX_OR_COPY_CODES_MAX; ++i) { for (i = 0; i < PIX_OR_COPY_CODES_MAX; ++i) {
p->literal_[i] += a->literal_[i]; p->literal_[i] += a->literal_[i];
@@ -90,8 +90,8 @@ static WEBP_INLINE void HistogramAdd(Histogram* const p,
} }
} }
static WEBP_INLINE void HistogramRemove(Histogram* const p, static WEBP_INLINE void VP8LHistogramRemove(VP8LHistogram* const p,
const Histogram* const a) { const VP8LHistogram* const a) {
int i; int i;
for (i = 0; i < PIX_OR_COPY_CODES_MAX; ++i) { for (i = 0; i < PIX_OR_COPY_CODES_MAX; ++i) {
p->literal_[i] -= a->literal_[i]; p->literal_[i] -= a->literal_[i];
@@ -111,39 +111,38 @@ static WEBP_INLINE void HistogramRemove(Histogram* const p,
} }
} }
static WEBP_INLINE int HistogramNumPixOrCopyCodes(const Histogram* const p) { static WEBP_INLINE int VP8LHistogramNumCodes(const VP8LHistogram* const p) {
return 256 + kLengthCodes + (1 << p->palette_code_bits_); return 256 + kLengthCodes + (1 << p->palette_code_bits_);
} }
void ConvertPopulationCountTableToBitEstimates( void VP8LConvertPopulationCountTableToBitEstimates(
int n, const int* const population_counts, double* const output); int n, const int* const population_counts, double* const output);
double ShannonEntropy(const int* const array, int n); double VP8LShannonEntropy(const int* const array, int n);
// Build a 2d image of histograms, subresolutioned by (1 << histobits) to // Build a 2d image of histograms, subresolutioned by (1 << histobits) to
// the original image. // the original image.
int BuildHistogramImage(int xsize, int ysize, int VP8LHistogramBuildImage(int xsize, int ysize,
int histobits, int histobits, int palette_bits,
int palette_bits, const PixOrCopy* backward_refs,
const PixOrCopy* backward_refs, int backward_refs_size,
int backward_refs_size, VP8LHistogram*** image,
Histogram*** image, int* histogram_size);
int* histogram_size);
// Combines several histograms into fewer histograms. // Combines several histograms into fewer histograms.
int CombineHistogramImage(Histogram** in, int VP8LHistogramCombine(VP8LHistogram** in,
int in_size, int in_size,
int quality, int quality,
Histogram*** out, VP8LHistogram*** out,
int* out_size); int* out_size);
// Moves histograms from one cluster to another if smaller entropy can // Moves histograms from one cluster to another if smaller entropy can
// be achieved by doing that. // be achieved by doing that.
void RefineHistogramImage(Histogram** raw, void VP8LHistogramRefine(VP8LHistogram** raw,
int raw_size, int raw_size,
uint32_t* symbols, uint32_t* symbols,
int out_size, int out_size,
Histogram** out); VP8LHistogram** out);
#if defined(__cplusplus) || defined(c_plusplus) #if defined(__cplusplus) || defined(c_plusplus)
} }