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Diffstat (limited to 'drivers/webpold/dsp/lossless.c')
| -rw-r--r-- | drivers/webpold/dsp/lossless.c | 1138 |
1 files changed, 1138 insertions, 0 deletions
diff --git a/drivers/webpold/dsp/lossless.c b/drivers/webpold/dsp/lossless.c new file mode 100644 index 0000000000..62a6b7b15a --- /dev/null +++ b/drivers/webpold/dsp/lossless.c @@ -0,0 +1,1138 @@ +// 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/ +// ----------------------------------------------------------------------------- +// +// Image transforms and color space conversion methods for lossless decoder. +// +// Authors: Vikas Arora (vikaas.arora@gmail.com) +// Jyrki Alakuijala (jyrki@google.com) +// Urvang Joshi (urvang@google.com) + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#include <math.h> +#include <stdlib.h> +#include "./lossless.h" +#include "../dec/vp8li.h" +#include "../dsp/yuv.h" +#include "../dsp/dsp.h" +#include "../enc/histogram.h" + +#define MAX_DIFF_COST (1e30f) + +// lookup table for small values of log2(int) +#define APPROX_LOG_MAX 4096 +#define LOG_2_RECIPROCAL 1.44269504088896338700465094007086 +#define LOG_LOOKUP_IDX_MAX 256 +static const float kLog2Table[LOG_LOOKUP_IDX_MAX] = { + 0.0000000000000000f, 0.0000000000000000f, + 1.0000000000000000f, 1.5849625007211560f, + 2.0000000000000000f, 2.3219280948873621f, + 2.5849625007211560f, 2.8073549220576041f, + 3.0000000000000000f, 3.1699250014423121f, + 3.3219280948873621f, 3.4594316186372973f, + 3.5849625007211560f, 3.7004397181410921f, + 3.8073549220576041f, 3.9068905956085187f, + 4.0000000000000000f, 4.0874628412503390f, + 4.1699250014423121f, 4.2479275134435852f, + 4.3219280948873626f, 4.3923174227787606f, + 4.4594316186372973f, 4.5235619560570130f, + 4.5849625007211560f, 4.6438561897747243f, + 4.7004397181410917f, 4.7548875021634682f, + 4.8073549220576037f, 4.8579809951275718f, + 4.9068905956085187f, 4.9541963103868749f, + 5.0000000000000000f, 5.0443941193584533f, + 5.0874628412503390f, 5.1292830169449663f, + 5.1699250014423121f, 5.2094533656289501f, + 5.2479275134435852f, 5.2854022188622487f, + 5.3219280948873626f, 5.3575520046180837f, + 5.3923174227787606f, 5.4262647547020979f, + 5.4594316186372973f, 5.4918530963296747f, + 5.5235619560570130f, 5.5545888516776376f, + 5.5849625007211560f, 5.6147098441152083f, + 5.6438561897747243f, 5.6724253419714951f, + 5.7004397181410917f, 5.7279204545631987f, + 5.7548875021634682f, 5.7813597135246599f, + 5.8073549220576037f, 5.8328900141647412f, + 5.8579809951275718f, 5.8826430493618415f, + 5.9068905956085187f, 5.9307373375628866f, + 5.9541963103868749f, 5.9772799234999167f, + 6.0000000000000000f, 6.0223678130284543f, + 6.0443941193584533f, 6.0660891904577720f, + 6.0874628412503390f, 6.1085244567781691f, + 6.1292830169449663f, 6.1497471195046822f, + 6.1699250014423121f, 6.1898245588800175f, + 6.2094533656289501f, 6.2288186904958804f, + 6.2479275134435852f, 6.2667865406949010f, + 6.2854022188622487f, 6.3037807481771030f, + 6.3219280948873626f, 6.3398500028846243f, + 6.3575520046180837f, 6.3750394313469245f, + 6.3923174227787606f, 6.4093909361377017f, + 6.4262647547020979f, 6.4429434958487279f, + 6.4594316186372973f, 6.4757334309663976f, + 6.4918530963296747f, 6.5077946401986963f, + 6.5235619560570130f, 6.5391588111080309f, + 6.5545888516776376f, 6.5698556083309478f, + 6.5849625007211560f, 6.5999128421871278f, + 6.6147098441152083f, 6.6293566200796094f, + 6.6438561897747243f, 6.6582114827517946f, + 6.6724253419714951f, 6.6865005271832185f, + 6.7004397181410917f, 6.7142455176661224f, + 6.7279204545631987f, 6.7414669864011464f, + 6.7548875021634682f, 6.7681843247769259f, + 6.7813597135246599f, 6.7944158663501061f, + 6.8073549220576037f, 6.8201789624151878f, + 6.8328900141647412f, 6.8454900509443747f, + 6.8579809951275718f, 6.8703647195834047f, + 6.8826430493618415f, 6.8948177633079437f, + 6.9068905956085187f, 6.9188632372745946f, + 6.9307373375628866f, 6.9425145053392398f, + 6.9541963103868749f, 6.9657842846620869f, + 6.9772799234999167f, 6.9886846867721654f, + 7.0000000000000000f, 7.0112272554232539f, + 7.0223678130284543f, 7.0334230015374501f, + 7.0443941193584533f, 7.0552824355011898f, + 7.0660891904577720f, 7.0768155970508308f, + 7.0874628412503390f, 7.0980320829605263f, + 7.1085244567781691f, 7.1189410727235076f, + 7.1292830169449663f, 7.1395513523987936f, + 7.1497471195046822f, 7.1598713367783890f, + 7.1699250014423121f, 7.1799090900149344f, + 7.1898245588800175f, 7.1996723448363644f, + 7.2094533656289501f, 7.2191685204621611f, + 7.2288186904958804f, 7.2384047393250785f, + 7.2479275134435852f, 7.2573878426926521f, + 7.2667865406949010f, 7.2761244052742375f, + 7.2854022188622487f, 7.2946207488916270f, + 7.3037807481771030f, 7.3128829552843557f, + 7.3219280948873626f, 7.3309168781146167f, + 7.3398500028846243f, 7.3487281542310771f, + 7.3575520046180837f, 7.3663222142458160f, + 7.3750394313469245f, 7.3837042924740519f, + 7.3923174227787606f, 7.4008794362821843f, + 7.4093909361377017f, 7.4178525148858982f, + 7.4262647547020979f, 7.4346282276367245f, + 7.4429434958487279f, 7.4512111118323289f, + 7.4594316186372973f, 7.4676055500829976f, + 7.4757334309663976f, 7.4838157772642563f, + 7.4918530963296747f, 7.4998458870832056f, + 7.5077946401986963f, 7.5156998382840427f, + 7.5235619560570130f, 7.5313814605163118f, + 7.5391588111080309f, 7.5468944598876364f, + 7.5545888516776376f, 7.5622424242210728f, + 7.5698556083309478f, 7.5774288280357486f, + 7.5849625007211560f, 7.5924570372680806f, + 7.5999128421871278f, 7.6073303137496104f, + 7.6147098441152083f, 7.6220518194563764f, + 7.6293566200796094f, 7.6366246205436487f, + 7.6438561897747243f, 7.6510516911789281f, + 7.6582114827517946f, 7.6653359171851764f, + 7.6724253419714951f, 7.6794800995054464f, + 7.6865005271832185f, 7.6934869574993252f, + 7.7004397181410917f, 7.7073591320808825f, + 7.7142455176661224f, 7.7210991887071855f, + 7.7279204545631987f, 7.7347096202258383f, + 7.7414669864011464f, 7.7481928495894605f, + 7.7548875021634682f, 7.7615512324444795f, + 7.7681843247769259f, 7.7747870596011736f, + 7.7813597135246599f, 7.7879025593914317f, + 7.7944158663501061f, 7.8008998999203047f, + 7.8073549220576037f, 7.8137811912170374f, + 7.8201789624151878f, 7.8265484872909150f, + 7.8328900141647412f, 7.8392037880969436f, + 7.8454900509443747f, 7.8517490414160571f, + 7.8579809951275718f, 7.8641861446542797f, + 7.8703647195834047f, 7.8765169465649993f, + 7.8826430493618415f, 7.8887432488982591f, + 7.8948177633079437f, 7.9008668079807486f, + 7.9068905956085187f, 7.9128893362299619f, + 7.9188632372745946f, 7.9248125036057812f, + 7.9307373375628866f, 7.9366379390025709f, + 7.9425145053392398f, 7.9483672315846778f, + 7.9541963103868749f, 7.9600019320680805f, + 7.9657842846620869f, 7.9715435539507719f, + 7.9772799234999167f, 7.9829935746943103f, + 7.9886846867721654f, 7.9943534368588577f +}; + +float VP8LFastLog2(int v) { + if (v < LOG_LOOKUP_IDX_MAX) { + return kLog2Table[v]; + } else if (v < APPROX_LOG_MAX) { + int log_cnt = 0; + while (v >= LOG_LOOKUP_IDX_MAX) { + ++log_cnt; + v = v >> 1; + } + return kLog2Table[v] + (float)log_cnt; + } else { + return (float)(LOG_2_RECIPROCAL * log((double)v)); + } +} + +//------------------------------------------------------------------------------ +// Image transforms. + +// In-place sum of each component with mod 256. +static WEBP_INLINE void AddPixelsEq(uint32_t* a, uint32_t b) { + const uint32_t alpha_and_green = (*a & 0xff00ff00u) + (b & 0xff00ff00u); + const uint32_t red_and_blue = (*a & 0x00ff00ffu) + (b & 0x00ff00ffu); + *a = (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); +} + +static WEBP_INLINE uint32_t Average2(uint32_t a0, uint32_t a1) { + return (((a0 ^ a1) & 0xfefefefeL) >> 1) + (a0 & a1); +} + +static WEBP_INLINE uint32_t Average3(uint32_t a0, uint32_t a1, uint32_t a2) { + return Average2(Average2(a0, a2), a1); +} + +static WEBP_INLINE uint32_t Average4(uint32_t a0, uint32_t a1, + uint32_t a2, uint32_t a3) { + return Average2(Average2(a0, a1), Average2(a2, a3)); +} + +static WEBP_INLINE uint32_t Clip255(uint32_t a) { + if (a < 256) { + return a; + } + // return 0, when a is a negative integer. + // return 255, when a is positive. + return ~a >> 24; +} + +static WEBP_INLINE int AddSubtractComponentFull(int a, int b, int c) { + return Clip255(a + b - c); +} + +static WEBP_INLINE uint32_t ClampedAddSubtractFull(uint32_t c0, uint32_t c1, + uint32_t c2) { + const int a = AddSubtractComponentFull(c0 >> 24, c1 >> 24, c2 >> 24); + const int r = AddSubtractComponentFull((c0 >> 16) & 0xff, + (c1 >> 16) & 0xff, + (c2 >> 16) & 0xff); + const int g = AddSubtractComponentFull((c0 >> 8) & 0xff, + (c1 >> 8) & 0xff, + (c2 >> 8) & 0xff); + const int b = AddSubtractComponentFull(c0 & 0xff, c1 & 0xff, c2 & 0xff); + return (a << 24) | (r << 16) | (g << 8) | b; +} + +static WEBP_INLINE int AddSubtractComponentHalf(int a, int b) { + return Clip255(a + (a - b) / 2); +} + +static WEBP_INLINE uint32_t ClampedAddSubtractHalf(uint32_t c0, uint32_t c1, + uint32_t c2) { + const uint32_t ave = Average2(c0, c1); + const int a = AddSubtractComponentHalf(ave >> 24, c2 >> 24); + const int r = AddSubtractComponentHalf((ave >> 16) & 0xff, (c2 >> 16) & 0xff); + const int g = AddSubtractComponentHalf((ave >> 8) & 0xff, (c2 >> 8) & 0xff); + const int b = AddSubtractComponentHalf((ave >> 0) & 0xff, (c2 >> 0) & 0xff); + return (a << 24) | (r << 16) | (g << 8) | b; +} + +static WEBP_INLINE int Sub3(int a, int b, int c) { + const int pa = b - c; + const int pb = a - c; + return abs(pa) - abs(pb); +} + +static WEBP_INLINE uint32_t Select(uint32_t a, uint32_t b, uint32_t c) { + const int pa_minus_pb = + Sub3((a >> 24) , (b >> 24) , (c >> 24) ) + + Sub3((a >> 16) & 0xff, (b >> 16) & 0xff, (c >> 16) & 0xff) + + Sub3((a >> 8) & 0xff, (b >> 8) & 0xff, (c >> 8) & 0xff) + + Sub3((a ) & 0xff, (b ) & 0xff, (c ) & 0xff); + + return (pa_minus_pb <= 0) ? a : b; +} + +//------------------------------------------------------------------------------ +// Predictors + +static uint32_t Predictor0(uint32_t left, const uint32_t* const top) { + (void)top; + (void)left; + return ARGB_BLACK; +} +static uint32_t Predictor1(uint32_t left, const uint32_t* const top) { + (void)top; + return left; +} +static uint32_t Predictor2(uint32_t left, const uint32_t* const top) { + (void)left; + return top[0]; +} +static uint32_t Predictor3(uint32_t left, const uint32_t* const top) { + (void)left; + return top[1]; +} +static uint32_t Predictor4(uint32_t left, const uint32_t* const top) { + (void)left; + return top[-1]; +} +static uint32_t Predictor5(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average3(left, top[0], top[1]); + return pred; +} +static uint32_t Predictor6(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average2(left, top[-1]); + return pred; +} +static uint32_t Predictor7(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average2(left, top[0]); + return pred; +} +static uint32_t Predictor8(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average2(top[-1], top[0]); + (void)left; + return pred; +} +static uint32_t Predictor9(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average2(top[0], top[1]); + (void)left; + return pred; +} +static uint32_t Predictor10(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Average4(left, top[-1], top[0], top[1]); + return pred; +} +static uint32_t Predictor11(uint32_t left, const uint32_t* const top) { + const uint32_t pred = Select(top[0], left, top[-1]); + return pred; +} +static uint32_t Predictor12(uint32_t left, const uint32_t* const top) { + const uint32_t pred = ClampedAddSubtractFull(left, top[0], top[-1]); + return pred; +} +static uint32_t Predictor13(uint32_t left, const uint32_t* const top) { + const uint32_t pred = ClampedAddSubtractHalf(left, top[0], top[-1]); + return pred; +} + +typedef uint32_t (*PredictorFunc)(uint32_t left, const uint32_t* const top); +static const PredictorFunc kPredictors[16] = { + Predictor0, Predictor1, Predictor2, Predictor3, + Predictor4, Predictor5, Predictor6, Predictor7, + Predictor8, Predictor9, Predictor10, Predictor11, + Predictor12, Predictor13, + Predictor0, Predictor0 // <- padding security sentinels +}; + +// TODO(vikasa): Replace 256 etc with defines. +static float PredictionCostSpatial(const int* counts, + int weight_0, double exp_val) { + const int significant_symbols = 16; + const double exp_decay_factor = 0.6; + double bits = weight_0 * counts[0]; + int i; + for (i = 1; i < significant_symbols; ++i) { + bits += exp_val * (counts[i] + counts[256 - i]); + exp_val *= exp_decay_factor; + } + return (float)(-0.1 * bits); +} + +// Compute the Shanon's entropy: Sum(p*log2(p)) +static float ShannonEntropy(const int* const array, int n) { + int i; + float retval = 0.f; + int sum = 0; + for (i = 0; i < n; ++i) { + if (array[i] != 0) { + sum += array[i]; + retval -= VP8LFastSLog2(array[i]); + } + } + retval += VP8LFastSLog2(sum); + return retval; +} + +static float PredictionCostSpatialHistogram(int accumulated[4][256], + int tile[4][256]) { + int i; + int k; + int combo[256]; + double retval = 0; + for (i = 0; i < 4; ++i) { + const double exp_val = 0.94; + retval += PredictionCostSpatial(&tile[i][0], 1, exp_val); + retval += ShannonEntropy(&tile[i][0], 256); + for (k = 0; k < 256; ++k) { + combo[k] = accumulated[i][k] + tile[i][k]; + } + retval += ShannonEntropy(&combo[0], 256); + } + return (float)retval; +} + +static int GetBestPredictorForTile(int width, int height, + int tile_x, int tile_y, int bits, + int accumulated[4][256], + const uint32_t* const argb_scratch) { + const int kNumPredModes = 14; + const int col_start = tile_x << bits; + const int row_start = tile_y << bits; + const int tile_size = 1 << bits; + const int ymax = (tile_size <= height - row_start) ? + tile_size : height - row_start; + const int xmax = (tile_size <= width - col_start) ? + tile_size : width - col_start; + int histo[4][256]; + float best_diff = MAX_DIFF_COST; + int best_mode = 0; + + int mode; + for (mode = 0; mode < kNumPredModes; ++mode) { + const uint32_t* current_row = argb_scratch; + const PredictorFunc pred_func = kPredictors[mode]; + float cur_diff; + int y; + memset(&histo[0][0], 0, sizeof(histo)); + for (y = 0; y < ymax; ++y) { + int x; + const int row = row_start + y; + const uint32_t* const upper_row = current_row; + current_row = upper_row + width; + for (x = 0; x < xmax; ++x) { + const int col = col_start + x; + uint32_t predict; + uint32_t predict_diff; + if (row == 0) { + predict = (col == 0) ? ARGB_BLACK : current_row[col - 1]; // Left. + } else if (col == 0) { + predict = upper_row[col]; // Top. + } else { + predict = pred_func(current_row[col - 1], upper_row + col); + } + predict_diff = VP8LSubPixels(current_row[col], predict); + ++histo[0][predict_diff >> 24]; + ++histo[1][((predict_diff >> 16) & 0xff)]; + ++histo[2][((predict_diff >> 8) & 0xff)]; + ++histo[3][(predict_diff & 0xff)]; + } + } + cur_diff = PredictionCostSpatialHistogram(accumulated, histo); + if (cur_diff < best_diff) { + best_diff = cur_diff; + best_mode = mode; + } + } + + return best_mode; +} + +static void CopyTileWithPrediction(int width, int height, + int tile_x, int tile_y, int bits, int mode, + const uint32_t* const argb_scratch, + uint32_t* const argb) { + const int col_start = tile_x << bits; + const int row_start = tile_y << bits; + const int tile_size = 1 << bits; + const int ymax = (tile_size <= height - row_start) ? + tile_size : height - row_start; + const int xmax = (tile_size <= width - col_start) ? + tile_size : width - col_start; + const PredictorFunc pred_func = kPredictors[mode]; + const uint32_t* current_row = argb_scratch; + + int y; + for (y = 0; y < ymax; ++y) { + int x; + const int row = row_start + y; + const uint32_t* const upper_row = current_row; + current_row = upper_row + width; + for (x = 0; x < xmax; ++x) { + const int col = col_start + x; + const int pix = row * width + col; + uint32_t predict; + if (row == 0) { + predict = (col == 0) ? ARGB_BLACK : current_row[col - 1]; // Left. + } else if (col == 0) { + predict = upper_row[col]; // Top. + } else { + predict = pred_func(current_row[col - 1], upper_row + col); + } + argb[pix] = VP8LSubPixels(current_row[col], predict); + } + } +} + +void VP8LResidualImage(int width, int height, int bits, + uint32_t* const argb, uint32_t* const argb_scratch, + uint32_t* const image) { + const int max_tile_size = 1 << bits; + const int tiles_per_row = VP8LSubSampleSize(width, bits); + const int tiles_per_col = VP8LSubSampleSize(height, bits); + uint32_t* const upper_row = argb_scratch; + uint32_t* const current_tile_rows = argb_scratch + width; + int tile_y; + int histo[4][256]; + memset(histo, 0, sizeof(histo)); + for (tile_y = 0; tile_y < tiles_per_col; ++tile_y) { + const int tile_y_offset = tile_y * max_tile_size; + const int this_tile_height = + (tile_y < tiles_per_col - 1) ? max_tile_size : height - tile_y_offset; + int tile_x; + if (tile_y > 0) { + memcpy(upper_row, current_tile_rows + (max_tile_size - 1) * width, + width * sizeof(*upper_row)); + } + memcpy(current_tile_rows, &argb[tile_y_offset * width], + this_tile_height * width * sizeof(*current_tile_rows)); + for (tile_x = 0; tile_x < tiles_per_row; ++tile_x) { + int pred; + int y; + const int tile_x_offset = tile_x * max_tile_size; + int all_x_max = tile_x_offset + max_tile_size; + if (all_x_max > width) { + all_x_max = width; + } + pred = GetBestPredictorForTile(width, height, tile_x, tile_y, bits, histo, + argb_scratch); + image[tile_y * tiles_per_row + tile_x] = 0xff000000u | (pred << 8); + CopyTileWithPrediction(width, height, tile_x, tile_y, bits, pred, + argb_scratch, argb); + for (y = 0; y < max_tile_size; ++y) { + int ix; + int all_x; + int all_y = tile_y_offset + y; + if (all_y >= height) { + break; + } + ix = all_y * width + tile_x_offset; + for (all_x = tile_x_offset; all_x < all_x_max; ++all_x, ++ix) { + const uint32_t a = argb[ix]; + ++histo[0][a >> 24]; + ++histo[1][((a >> 16) & 0xff)]; + ++histo[2][((a >> 8) & 0xff)]; + ++histo[3][(a & 0xff)]; + } + } + } + } +} + +// Inverse prediction. +static void PredictorInverseTransform(const VP8LTransform* const transform, + int y_start, int y_end, uint32_t* data) { + const int width = transform->xsize_; + if (y_start == 0) { // First Row follows the L (mode=1) mode. + int x; + const uint32_t pred0 = Predictor0(data[-1], NULL); + AddPixelsEq(data, pred0); + for (x = 1; x < width; ++x) { + const uint32_t pred1 = Predictor1(data[x - 1], NULL); + AddPixelsEq(data + x, pred1); + } + data += width; + ++y_start; + } + + { + int y = y_start; + const int mask = (1 << transform->bits_) - 1; + const int tiles_per_row = VP8LSubSampleSize(width, transform->bits_); + const uint32_t* pred_mode_base = + transform->data_ + (y >> transform->bits_) * tiles_per_row; + + while (y < y_end) { + int x; + const uint32_t pred2 = Predictor2(data[-1], data - width); + const uint32_t* pred_mode_src = pred_mode_base; + PredictorFunc pred_func; + + // First pixel follows the T (mode=2) mode. + AddPixelsEq(data, pred2); + + // .. the rest: + pred_func = kPredictors[((*pred_mode_src++) >> 8) & 0xf]; + for (x = 1; x < width; ++x) { + uint32_t pred; + if ((x & mask) == 0) { // start of tile. Read predictor function. + pred_func = kPredictors[((*pred_mode_src++) >> 8) & 0xf]; + } + pred = pred_func(data[x - 1], data + x - width); + AddPixelsEq(data + x, pred); + } + data += width; + ++y; + if ((y & mask) == 0) { // Use the same mask, since tiles are squares. + pred_mode_base += tiles_per_row; + } + } + } +} + +void VP8LSubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixs) { + int i; + for (i = 0; i < num_pixs; ++i) { + const uint32_t argb = argb_data[i]; + const uint32_t green = (argb >> 8) & 0xff; + const uint32_t new_r = (((argb >> 16) & 0xff) - green) & 0xff; + const uint32_t new_b = ((argb & 0xff) - green) & 0xff; + argb_data[i] = (argb & 0xff00ff00) | (new_r << 16) | new_b; + } +} + +// Add green to blue and red channels (i.e. perform the inverse transform of +// 'subtract green'). +static void AddGreenToBlueAndRed(const VP8LTransform* const transform, + int y_start, int y_end, uint32_t* data) { + const int width = transform->xsize_; + const uint32_t* const data_end = data + (y_end - y_start) * width; + while (data < data_end) { + const uint32_t argb = *data; + // "* 0001001u" is equivalent to "(green << 16) + green)" + const uint32_t green = ((argb >> 8) & 0xff); + uint32_t red_blue = (argb & 0x00ff00ffu); + red_blue += (green << 16) | green; + red_blue &= 0x00ff00ffu; + *data++ = (argb & 0xff00ff00u) | red_blue; + } +} + +typedef struct { + // Note: the members are uint8_t, so that any negative values are + // automatically converted to "mod 256" values. + uint8_t green_to_red_; + uint8_t green_to_blue_; + uint8_t red_to_blue_; +} Multipliers; + +static WEBP_INLINE void MultipliersClear(Multipliers* m) { + m->green_to_red_ = 0; + m->green_to_blue_ = 0; + m->red_to_blue_ = 0; +} + +static WEBP_INLINE uint32_t ColorTransformDelta(int8_t color_pred, + int8_t color) { + return (uint32_t)((int)(color_pred) * color) >> 5; +} + +static WEBP_INLINE void ColorCodeToMultipliers(uint32_t color_code, + Multipliers* const m) { + m->green_to_red_ = (color_code >> 0) & 0xff; + m->green_to_blue_ = (color_code >> 8) & 0xff; + m->red_to_blue_ = (color_code >> 16) & 0xff; +} + +static WEBP_INLINE uint32_t MultipliersToColorCode(Multipliers* const m) { + return 0xff000000u | + ((uint32_t)(m->red_to_blue_) << 16) | + ((uint32_t)(m->green_to_blue_) << 8) | + m->green_to_red_; +} + +static WEBP_INLINE uint32_t TransformColor(const Multipliers* const m, + uint32_t argb, int inverse) { + const uint32_t green = argb >> 8; + const uint32_t red = argb >> 16; + uint32_t new_red = red; + uint32_t new_blue = argb; + + if (inverse) { + new_red += ColorTransformDelta(m->green_to_red_, green); + new_red &= 0xff; + new_blue += ColorTransformDelta(m->green_to_blue_, green); + new_blue += ColorTransformDelta(m->red_to_blue_, new_red); + new_blue &= 0xff; + } else { + new_red -= ColorTransformDelta(m->green_to_red_, green); + new_red &= 0xff; + new_blue -= ColorTransformDelta(m->green_to_blue_, green); + new_blue -= ColorTransformDelta(m->red_to_blue_, red); + new_blue &= 0xff; + } + return (argb & 0xff00ff00u) | (new_red << 16) | (new_blue); +} + +static WEBP_INLINE int SkipRepeatedPixels(const uint32_t* const argb, + int ix, int xsize) { + const uint32_t v = argb[ix]; + if (ix >= xsize + 3) { + if (v == argb[ix - xsize] && + argb[ix - 1] == argb[ix - xsize - 1] && + argb[ix - 2] == argb[ix - xsize - 2] && + argb[ix - 3] == argb[ix - xsize - 3]) { + return 1; + } + return v == argb[ix - 3] && v == argb[ix - 2] && v == argb[ix - 1]; + } else if (ix >= 3) { + return v == argb[ix - 3] && v == argb[ix - 2] && v == argb[ix - 1]; + } + return 0; +} + +static float PredictionCostCrossColor(const int accumulated[256], + const int counts[256]) { + // Favor low entropy, locally and globally. + int i; + int combo[256]; + for (i = 0; i < 256; ++i) { + combo[i] = accumulated[i] + counts[i]; + } + return ShannonEntropy(combo, 256) + + ShannonEntropy(counts, 256) + + PredictionCostSpatial(counts, 3, 2.4); // Favor small absolute values. +} + +static Multipliers GetBestColorTransformForTile( + int tile_x, int tile_y, int bits, + Multipliers prevX, + Multipliers prevY, + int step, int xsize, int ysize, + int* accumulated_red_histo, + int* accumulated_blue_histo, + const uint32_t* const argb) { + float best_diff = MAX_DIFF_COST; + float cur_diff; + const int halfstep = step / 2; + const int max_tile_size = 1 << bits; + const int tile_y_offset = tile_y * max_tile_size; + const int tile_x_offset = tile_x * max_tile_size; + int green_to_red; + int green_to_blue; + int red_to_blue; + int all_x_max = tile_x_offset + max_tile_size; + int all_y_max = tile_y_offset + max_tile_size; + Multipliers best_tx; + MultipliersClear(&best_tx); + if (all_x_max > xsize) { + all_x_max = xsize; + } + if (all_y_max > ysize) { + all_y_max = ysize; + } + for (green_to_red = -64; green_to_red <= 64; green_to_red += halfstep) { + int histo[256] = { 0 }; + int all_y; + Multipliers tx; + MultipliersClear(&tx); + tx.green_to_red_ = green_to_red & 0xff; + + for (all_y = tile_y_offset; all_y < all_y_max; ++all_y) { + uint32_t predict; + int ix = all_y * xsize + tile_x_offset; + int all_x; + for (all_x = tile_x_offset; all_x < all_x_max; ++all_x, ++ix) { + if (SkipRepeatedPixels(argb, ix, xsize)) { + continue; + } + predict = TransformColor(&tx, argb[ix], 0); + ++histo[(predict >> 16) & 0xff]; // red. + } + } + cur_diff = PredictionCostCrossColor(&accumulated_red_histo[0], &histo[0]); + if (tx.green_to_red_ == prevX.green_to_red_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.green_to_red_ == prevY.green_to_red_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.green_to_red_ == 0) { + cur_diff -= 3; + } + if (cur_diff < best_diff) { + best_diff = cur_diff; + best_tx = tx; + } + } + best_diff = MAX_DIFF_COST; + green_to_red = best_tx.green_to_red_; + for (green_to_blue = -32; green_to_blue <= 32; green_to_blue += step) { + for (red_to_blue = -32; red_to_blue <= 32; red_to_blue += step) { + int all_y; + int histo[256] = { 0 }; + Multipliers tx; + tx.green_to_red_ = green_to_red; + tx.green_to_blue_ = green_to_blue; + tx.red_to_blue_ = red_to_blue; + for (all_y = tile_y_offset; all_y < all_y_max; ++all_y) { + uint32_t predict; + int all_x; + int ix = all_y * xsize + tile_x_offset; + for (all_x = tile_x_offset; all_x < all_x_max; ++all_x, ++ix) { + if (SkipRepeatedPixels(argb, ix, xsize)) { + continue; + } + predict = TransformColor(&tx, argb[ix], 0); + ++histo[predict & 0xff]; // blue. + } + } + cur_diff = + PredictionCostCrossColor(&accumulated_blue_histo[0], &histo[0]); + if (tx.green_to_blue_ == prevX.green_to_blue_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.green_to_blue_ == prevY.green_to_blue_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.red_to_blue_ == prevX.red_to_blue_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.red_to_blue_ == prevY.red_to_blue_) { + cur_diff -= 3; // favor keeping the areas locally similar + } + if (tx.green_to_blue_ == 0) { + cur_diff -= 3; + } + if (tx.red_to_blue_ == 0) { + cur_diff -= 3; + } + if (cur_diff < best_diff) { + best_diff = cur_diff; + best_tx = tx; + } + } + } + return best_tx; +} + +static void CopyTileWithColorTransform(int xsize, int ysize, + int tile_x, int tile_y, int bits, + Multipliers color_transform, + uint32_t* const argb) { + int y; + int xscan = 1 << bits; + int yscan = 1 << bits; + tile_x <<= bits; + tile_y <<= bits; + if (xscan > xsize - tile_x) { + xscan = xsize - tile_x; + } + if (yscan > ysize - tile_y) { + yscan = ysize - tile_y; + } + yscan += tile_y; + for (y = tile_y; y < yscan; ++y) { + int ix = y * xsize + tile_x; + const int end_ix = ix + xscan; + for (; ix < end_ix; ++ix) { + argb[ix] = TransformColor(&color_transform, argb[ix], 0); + } + } +} + +void VP8LColorSpaceTransform(int width, int height, int bits, int step, + uint32_t* const argb, uint32_t* image) { + const int max_tile_size = 1 << bits; + int tile_xsize = VP8LSubSampleSize(width, bits); + int tile_ysize = VP8LSubSampleSize(height, bits); + int accumulated_red_histo[256] = { 0 }; + int accumulated_blue_histo[256] = { 0 }; + int tile_y; + int tile_x; + Multipliers prevX; + Multipliers prevY; + MultipliersClear(&prevY); + MultipliersClear(&prevX); + for (tile_y = 0; tile_y < tile_ysize; ++tile_y) { + for (tile_x = 0; tile_x < tile_xsize; ++tile_x) { + Multipliers color_transform; + int all_x_max; + int y; + const int tile_y_offset = tile_y * max_tile_size; + const int tile_x_offset = tile_x * max_tile_size; + if (tile_y != 0) { + ColorCodeToMultipliers(image[tile_y * tile_xsize + tile_x - 1], &prevX); + ColorCodeToMultipliers(image[(tile_y - 1) * tile_xsize + tile_x], + &prevY); + } else if (tile_x != 0) { + ColorCodeToMultipliers(image[tile_y * tile_xsize + tile_x - 1], &prevX); + } + color_transform = + GetBestColorTransformForTile(tile_x, tile_y, bits, + prevX, prevY, + step, width, height, + &accumulated_red_histo[0], + &accumulated_blue_histo[0], + argb); + image[tile_y * tile_xsize + tile_x] = + MultipliersToColorCode(&color_transform); + CopyTileWithColorTransform(width, height, tile_x, tile_y, bits, + color_transform, argb); + + // Gather accumulated histogram data. + all_x_max = tile_x_offset + max_tile_size; + if (all_x_max > width) { + all_x_max = width; + } + for (y = 0; y < max_tile_size; ++y) { + int ix; + int all_x; + int all_y = tile_y_offset + y; + if (all_y >= height) { + break; + } + ix = all_y * width + tile_x_offset; + for (all_x = tile_x_offset; all_x < all_x_max; ++all_x, ++ix) { + if (ix >= 2 && + argb[ix] == argb[ix - 2] && + argb[ix] == argb[ix - 1]) { + continue; // repeated pixels are handled by backward references + } + if (ix >= width + 2 && + argb[ix - 2] == argb[ix - width - 2] && + argb[ix - 1] == argb[ix - width - 1] && + argb[ix] == argb[ix - width]) { + continue; // repeated pixels are handled by backward references + } + ++accumulated_red_histo[(argb[ix] >> 16) & 0xff]; + ++accumulated_blue_histo[argb[ix] & 0xff]; + } + } + } + } +} + +// Color space inverse transform. +static void ColorSpaceInverseTransform(const VP8LTransform* const transform, + int y_start, int y_end, uint32_t* data) { + const int width = transform->xsize_; + const int mask = (1 << transform->bits_) - 1; + const int tiles_per_row = VP8LSubSampleSize(width, transform->bits_); + int y = y_start; + const uint32_t* pred_row = + transform->data_ + (y >> transform->bits_) * tiles_per_row; + + while (y < y_end) { + const uint32_t* pred = pred_row; + Multipliers m = { 0, 0, 0 }; + int x; + + for (x = 0; x < width; ++x) { + if ((x & mask) == 0) ColorCodeToMultipliers(*pred++, &m); + data[x] = TransformColor(&m, data[x], 1); + } + data += width; + ++y; + if ((y & mask) == 0) pred_row += tiles_per_row;; + } +} + +// Separate out pixels packed together using pixel-bundling. +static void ColorIndexInverseTransform( + const VP8LTransform* const transform, + int y_start, int y_end, const uint32_t* src, uint32_t* dst) { + int y; + const int bits_per_pixel = 8 >> transform->bits_; + const int width = transform->xsize_; + const uint32_t* const color_map = transform->data_; + if (bits_per_pixel < 8) { + const int pixels_per_byte = 1 << transform->bits_; + const int count_mask = pixels_per_byte - 1; + const uint32_t bit_mask = (1 << bits_per_pixel) - 1; + for (y = y_start; y < y_end; ++y) { + uint32_t packed_pixels = 0; + int x; + for (x = 0; x < width; ++x) { + // We need to load fresh 'packed_pixels' once every 'pixels_per_byte' + // increments of x. Fortunately, pixels_per_byte is a power of 2, so + // can just use a mask for that, instead of decrementing a counter. + if ((x & count_mask) == 0) packed_pixels = ((*src++) >> 8) & 0xff; + *dst++ = color_map[packed_pixels & bit_mask]; + packed_pixels >>= bits_per_pixel; + } + } + } else { + for (y = y_start; y < y_end; ++y) { + int x; + for (x = 0; x < width; ++x) { + *dst++ = color_map[((*src++) >> 8) & 0xff]; + } + } + } +} + +void VP8LInverseTransform(const VP8LTransform* const transform, + int row_start, int row_end, + const uint32_t* const in, uint32_t* const out) { + assert(row_start < row_end); + assert(row_end <= transform->ysize_); + switch (transform->type_) { + case SUBTRACT_GREEN: + AddGreenToBlueAndRed(transform, row_start, row_end, out); + break; + case PREDICTOR_TRANSFORM: + PredictorInverseTransform(transform, row_start, row_end, out); + if (row_end != transform->ysize_) { + // The last predicted row in this iteration will be the top-pred row + // for the first row in next iteration. + const int width = transform->xsize_; + memcpy(out - width, out + (row_end - row_start - 1) * width, + width * sizeof(*out)); + } + break; + case CROSS_COLOR_TRANSFORM: + ColorSpaceInverseTransform(transform, row_start, row_end, out); + break; + case COLOR_INDEXING_TRANSFORM: + if (in == out && transform->bits_ > 0) { + // Move packed pixels to the end of unpacked region, so that unpacking + // can occur seamlessly. + // Also, note that this is the only transform that applies on + // the effective width of VP8LSubSampleSize(xsize_, bits_). All other + // transforms work on effective width of xsize_. + const int out_stride = (row_end - row_start) * transform->xsize_; + const int in_stride = (row_end - row_start) * + VP8LSubSampleSize(transform->xsize_, transform->bits_); + uint32_t* const src = out + out_stride - in_stride; + memmove(src, out, in_stride * sizeof(*src)); + ColorIndexInverseTransform(transform, row_start, row_end, src, out); + } else { + ColorIndexInverseTransform(transform, row_start, row_end, in, out); + } + break; + } +} + +//------------------------------------------------------------------------------ +// Color space conversion. + +static int is_big_endian(void) { + static const union { + uint16_t w; + uint8_t b[2]; + } tmp = { 1 }; + return (tmp.b[0] != 1); +} + +static void ConvertBGRAToRGB(const uint32_t* src, + int num_pixels, uint8_t* dst) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + const uint32_t argb = *src++; + *dst++ = (argb >> 16) & 0xff; + *dst++ = (argb >> 8) & 0xff; + *dst++ = (argb >> 0) & 0xff; + } +} + +static void ConvertBGRAToRGBA(const uint32_t* src, + int num_pixels, uint8_t* dst) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + const uint32_t argb = *src++; + *dst++ = (argb >> 16) & 0xff; + *dst++ = (argb >> 8) & 0xff; + *dst++ = (argb >> 0) & 0xff; + *dst++ = (argb >> 24) & 0xff; + } +} + +static void ConvertBGRAToRGBA4444(const uint32_t* src, + int num_pixels, uint8_t* dst) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + const uint32_t argb = *src++; + *dst++ = ((argb >> 16) & 0xf0) | ((argb >> 12) & 0xf); + *dst++ = ((argb >> 0) & 0xf0) | ((argb >> 28) & 0xf); + } +} + +static void ConvertBGRAToRGB565(const uint32_t* src, + int num_pixels, uint8_t* dst) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + const uint32_t argb = *src++; + *dst++ = ((argb >> 16) & 0xf8) | ((argb >> 13) & 0x7); + *dst++ = ((argb >> 5) & 0xe0) | ((argb >> 3) & 0x1f); + } +} + +static void ConvertBGRAToBGR(const uint32_t* src, + int num_pixels, uint8_t* dst) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + const uint32_t argb = *src++; + *dst++ = (argb >> 0) & 0xff; + *dst++ = (argb >> 8) & 0xff; + *dst++ = (argb >> 16) & 0xff; + } +} + +static void CopyOrSwap(const uint32_t* src, int num_pixels, uint8_t* dst, + int swap_on_big_endian) { + if (is_big_endian() == swap_on_big_endian) { + const uint32_t* const src_end = src + num_pixels; + while (src < src_end) { + uint32_t argb = *src++; +#if !defined(__BIG_ENDIAN__) && (defined(__i386__) || defined(__x86_64__)) + __asm__ volatile("bswap %0" : "=r"(argb) : "0"(argb)); + *(uint32_t*)dst = argb; + dst += sizeof(argb); +#elif !defined(__BIG_ENDIAN__) && defined(_MSC_VER) + argb = _byteswap_ulong(argb); + *(uint32_t*)dst = argb; + dst += sizeof(argb); +#else + *dst++ = (argb >> 24) & 0xff; + *dst++ = (argb >> 16) & 0xff; + *dst++ = (argb >> 8) & 0xff; + *dst++ = (argb >> 0) & 0xff; +#endif + } + } else { + memcpy(dst, src, num_pixels * sizeof(*src)); + } +} + +void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels, + WEBP_CSP_MODE out_colorspace, uint8_t* const rgba) { + switch (out_colorspace) { + case MODE_RGB: + ConvertBGRAToRGB(in_data, num_pixels, rgba); + break; + case MODE_RGBA: + ConvertBGRAToRGBA(in_data, num_pixels, rgba); + break; + case MODE_rgbA: + ConvertBGRAToRGBA(in_data, num_pixels, rgba); + WebPApplyAlphaMultiply(rgba, 0, num_pixels, 1, 0); + break; + case MODE_BGR: + ConvertBGRAToBGR(in_data, num_pixels, rgba); + break; + case MODE_BGRA: + CopyOrSwap(in_data, num_pixels, rgba, 1); + break; + case MODE_bgrA: + CopyOrSwap(in_data, num_pixels, rgba, 1); + WebPApplyAlphaMultiply(rgba, 0, num_pixels, 1, 0); + break; + case MODE_ARGB: + CopyOrSwap(in_data, num_pixels, rgba, 0); + break; + case MODE_Argb: + CopyOrSwap(in_data, num_pixels, rgba, 0); + WebPApplyAlphaMultiply(rgba, 1, num_pixels, 1, 0); + break; + case MODE_RGBA_4444: + ConvertBGRAToRGBA4444(in_data, num_pixels, rgba); + break; + case MODE_rgbA_4444: + ConvertBGRAToRGBA4444(in_data, num_pixels, rgba); + WebPApplyAlphaMultiply4444(rgba, num_pixels, 1, 0); + break; + case MODE_RGB_565: + ConvertBGRAToRGB565(in_data, num_pixels, rgba); + break; + default: + assert(0); // Code flow should not reach here. + } +} + +//------------------------------------------------------------------------------ + +#if defined(__cplusplus) || defined(c_plusplus) +} // extern "C" +#endif |