1// Copyright 2012 Google Inc. All Rights Reserved. 2// 3// Use of this source code is governed by a BSD-style license 4// that can be found in the COPYING file in the root of the source 5// tree. An additional intellectual property rights grant can be found 6// in the file PATENTS. All contributing project authors may 7// be found in the AUTHORS file in the root of the source tree. 8// ----------------------------------------------------------------------------- 9// 10// Image transforms and color space conversion methods for lossless decoder. 11// 12// Authors: Vikas Arora (vikaas.arora@gmail.com) 13// Jyrki Alakuijala (jyrki@google.com) 14 15#ifndef WEBP_DSP_LOSSLESS_H_ 16#define WEBP_DSP_LOSSLESS_H_ 17 18#include "../webp/types.h" 19#include "../webp/decode.h" 20 21#include "../enc/histogram.h" 22#include "../utils/utils.h" 23 24#ifdef __cplusplus 25extern "C" { 26#endif 27 28#ifdef WEBP_EXPERIMENTAL_FEATURES 29#include "../enc/delta_palettization.h" 30#endif // WEBP_EXPERIMENTAL_FEATURES 31 32//------------------------------------------------------------------------------ 33// Decoding 34 35typedef uint32_t (*VP8LPredictorFunc)(uint32_t left, const uint32_t* const top); 36extern VP8LPredictorFunc VP8LPredictors[16]; 37 38typedef void (*VP8LProcessBlueAndRedFunc)(uint32_t* argb_data, int num_pixels); 39extern VP8LProcessBlueAndRedFunc VP8LAddGreenToBlueAndRed; 40 41typedef struct { 42 // Note: the members are uint8_t, so that any negative values are 43 // automatically converted to "mod 256" values. 44 uint8_t green_to_red_; 45 uint8_t green_to_blue_; 46 uint8_t red_to_blue_; 47} VP8LMultipliers; 48typedef void (*VP8LTransformColorFunc)(const VP8LMultipliers* const m, 49 uint32_t* argb_data, int num_pixels); 50extern VP8LTransformColorFunc VP8LTransformColorInverse; 51 52struct VP8LTransform; // Defined in dec/vp8li.h. 53 54// Performs inverse transform of data given transform information, start and end 55// rows. Transform will be applied to rows [row_start, row_end[. 56// The *in and *out pointers refer to source and destination data respectively 57// corresponding to the intermediate row (row_start). 58void VP8LInverseTransform(const struct VP8LTransform* const transform, 59 int row_start, int row_end, 60 const uint32_t* const in, uint32_t* const out); 61 62// Color space conversion. 63typedef void (*VP8LConvertFunc)(const uint32_t* src, int num_pixels, 64 uint8_t* dst); 65extern VP8LConvertFunc VP8LConvertBGRAToRGB; 66extern VP8LConvertFunc VP8LConvertBGRAToRGBA; 67extern VP8LConvertFunc VP8LConvertBGRAToRGBA4444; 68extern VP8LConvertFunc VP8LConvertBGRAToRGB565; 69extern VP8LConvertFunc VP8LConvertBGRAToBGR; 70 71// Converts from BGRA to other color spaces. 72void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels, 73 WEBP_CSP_MODE out_colorspace, uint8_t* const rgba); 74 75// color mapping related functions. 76static WEBP_INLINE uint32_t VP8GetARGBIndex(uint32_t idx) { 77 return (idx >> 8) & 0xff; 78} 79 80static WEBP_INLINE uint8_t VP8GetAlphaIndex(uint8_t idx) { 81 return idx; 82} 83 84static WEBP_INLINE uint32_t VP8GetARGBValue(uint32_t val) { 85 return val; 86} 87 88static WEBP_INLINE uint8_t VP8GetAlphaValue(uint32_t val) { 89 return (val >> 8) & 0xff; 90} 91 92typedef void (*VP8LMapARGBFunc)(const uint32_t* src, 93 const uint32_t* const color_map, 94 uint32_t* dst, int y_start, 95 int y_end, int width); 96typedef void (*VP8LMapAlphaFunc)(const uint8_t* src, 97 const uint32_t* const color_map, 98 uint8_t* dst, int y_start, 99 int y_end, int width); 100 101extern VP8LMapARGBFunc VP8LMapColor32b; 102extern VP8LMapAlphaFunc VP8LMapColor8b; 103 104// Similar to the static method ColorIndexInverseTransform() that is part of 105// lossless.c, but used only for alpha decoding. It takes uint8_t (rather than 106// uint32_t) arguments for 'src' and 'dst'. 107void VP8LColorIndexInverseTransformAlpha( 108 const struct VP8LTransform* const transform, int y_start, int y_end, 109 const uint8_t* src, uint8_t* dst); 110 111// Expose some C-only fallback functions 112void VP8LTransformColorInverse_C(const VP8LMultipliers* const m, 113 uint32_t* data, int num_pixels); 114 115void VP8LConvertBGRAToRGB_C(const uint32_t* src, int num_pixels, uint8_t* dst); 116void VP8LConvertBGRAToRGBA_C(const uint32_t* src, int num_pixels, uint8_t* dst); 117void VP8LConvertBGRAToRGBA4444_C(const uint32_t* src, 118 int num_pixels, uint8_t* dst); 119void VP8LConvertBGRAToRGB565_C(const uint32_t* src, 120 int num_pixels, uint8_t* dst); 121void VP8LConvertBGRAToBGR_C(const uint32_t* src, int num_pixels, uint8_t* dst); 122void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels); 123 124// Must be called before calling any of the above methods. 125void VP8LDspInit(void); 126 127//------------------------------------------------------------------------------ 128// Encoding 129 130extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed; 131extern VP8LTransformColorFunc VP8LTransformColor; 132typedef void (*VP8LCollectColorBlueTransformsFunc)( 133 const uint32_t* argb, int stride, 134 int tile_width, int tile_height, 135 int green_to_blue, int red_to_blue, int histo[]); 136extern VP8LCollectColorBlueTransformsFunc VP8LCollectColorBlueTransforms; 137 138typedef void (*VP8LCollectColorRedTransformsFunc)( 139 const uint32_t* argb, int stride, 140 int tile_width, int tile_height, 141 int green_to_red, int histo[]); 142extern VP8LCollectColorRedTransformsFunc VP8LCollectColorRedTransforms; 143 144// Expose some C-only fallback functions 145void VP8LTransformColor_C(const VP8LMultipliers* const m, 146 uint32_t* data, int num_pixels); 147void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels); 148void VP8LCollectColorRedTransforms_C(const uint32_t* argb, int stride, 149 int tile_width, int tile_height, 150 int green_to_red, int histo[]); 151void VP8LCollectColorBlueTransforms_C(const uint32_t* argb, int stride, 152 int tile_width, int tile_height, 153 int green_to_blue, int red_to_blue, 154 int histo[]); 155 156//------------------------------------------------------------------------------ 157// Image transforms. 158 159void VP8LResidualImage(int width, int height, int bits, int low_effort, 160 uint32_t* const argb, uint32_t* const argb_scratch, 161 uint32_t* const image, int exact); 162 163void VP8LColorSpaceTransform(int width, int height, int bits, int quality, 164 uint32_t* const argb, uint32_t* image); 165 166//------------------------------------------------------------------------------ 167// Misc methods. 168 169// Computes sampled size of 'size' when sampling using 'sampling bits'. 170static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size, 171 uint32_t sampling_bits) { 172 return (size + (1 << sampling_bits) - 1) >> sampling_bits; 173} 174 175// ----------------------------------------------------------------------------- 176// Faster logarithm for integers. Small values use a look-up table. 177 178// The threshold till approximate version of log_2 can be used. 179// Practically, we can get rid of the call to log() as the two values match to 180// very high degree (the ratio of these two is 0.99999x). 181// Keeping a high threshold for now. 182#define APPROX_LOG_WITH_CORRECTION_MAX 65536 183#define APPROX_LOG_MAX 4096 184#define LOG_2_RECIPROCAL 1.44269504088896338700465094007086 185#define LOG_LOOKUP_IDX_MAX 256 186extern const float kLog2Table[LOG_LOOKUP_IDX_MAX]; 187extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX]; 188typedef float (*VP8LFastLog2SlowFunc)(uint32_t v); 189 190extern VP8LFastLog2SlowFunc VP8LFastLog2Slow; 191extern VP8LFastLog2SlowFunc VP8LFastSLog2Slow; 192 193static WEBP_INLINE float VP8LFastLog2(uint32_t v) { 194 return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v); 195} 196// Fast calculation of v * log2(v) for integer input. 197static WEBP_INLINE float VP8LFastSLog2(uint32_t v) { 198 return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v); 199} 200 201// ----------------------------------------------------------------------------- 202// Huffman-cost related functions. 203 204typedef double (*VP8LCostFunc)(const uint32_t* population, int length); 205typedef double (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y, 206 int length); 207typedef float (*VP8LCombinedShannonEntropyFunc)(const int X[256], 208 const int Y[256]); 209 210extern VP8LCostFunc VP8LExtraCost; 211extern VP8LCostCombinedFunc VP8LExtraCostCombined; 212extern VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy; 213 214typedef struct { // small struct to hold counters 215 int counts[2]; // index: 0=zero steak, 1=non-zero streak 216 int streaks[2][2]; // [zero/non-zero][streak<3 / streak>=3] 217} VP8LStreaks; 218 219typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X, 220 const uint32_t* Y, int length); 221 222extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount; 223 224typedef struct { // small struct to hold bit entropy results 225 double entropy; // entropy 226 uint32_t sum; // sum of the population 227 int nonzeros; // number of non-zero elements in the population 228 uint32_t max_val; // maximum value in the population 229 uint32_t nonzero_code; // index of the last non-zero in the population 230} VP8LBitEntropy; 231 232void VP8LBitEntropyInit(VP8LBitEntropy* const entropy); 233 234// Get the combined symbol bit entropy and Huffman cost stats for the 235// distributions 'X' and 'Y'. Those results can then be refined according to 236// codec specific heuristics. 237void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X, 238 const uint32_t* const Y, int length, 239 VP8LBitEntropy* const bit_entropy, 240 VP8LStreaks* const stats); 241// Get the entropy for the distribution 'X'. 242void VP8LGetEntropyUnrefined(const uint32_t* const X, int length, 243 VP8LBitEntropy* const bit_entropy, 244 VP8LStreaks* const stats); 245 246void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n, 247 VP8LBitEntropy* const entropy); 248 249typedef void (*GetEntropyUnrefinedHelperFunc)(uint32_t val, int i, 250 uint32_t* const val_prev, 251 int* const i_prev, 252 VP8LBitEntropy* const bit_entropy, 253 VP8LStreaks* const stats); 254// Internal function used by VP8LGet*EntropyUnrefined. 255extern GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper; 256 257typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a, 258 const VP8LHistogram* const b, 259 VP8LHistogram* const out); 260extern VP8LHistogramAddFunc VP8LHistogramAdd; 261 262// ----------------------------------------------------------------------------- 263// PrefixEncode() 264 265static WEBP_INLINE int VP8LBitsLog2Ceiling(uint32_t n) { 266 const int log_floor = BitsLog2Floor(n); 267 if (n == (n & ~(n - 1))) // zero or a power of two. 268 return log_floor; 269 else 270 return log_floor + 1; 271} 272 273// Splitting of distance and length codes into prefixes and 274// extra bits. The prefixes are encoded with an entropy code 275// while the extra bits are stored just as normal bits. 276static WEBP_INLINE void VP8LPrefixEncodeBitsNoLUT(int distance, int* const code, 277 int* const extra_bits) { 278 const int highest_bit = BitsLog2Floor(--distance); 279 const int second_highest_bit = (distance >> (highest_bit - 1)) & 1; 280 *extra_bits = highest_bit - 1; 281 *code = 2 * highest_bit + second_highest_bit; 282} 283 284static WEBP_INLINE void VP8LPrefixEncodeNoLUT(int distance, int* const code, 285 int* const extra_bits, 286 int* const extra_bits_value) { 287 const int highest_bit = BitsLog2Floor(--distance); 288 const int second_highest_bit = (distance >> (highest_bit - 1)) & 1; 289 *extra_bits = highest_bit - 1; 290 *extra_bits_value = distance & ((1 << *extra_bits) - 1); 291 *code = 2 * highest_bit + second_highest_bit; 292} 293 294#define PREFIX_LOOKUP_IDX_MAX 512 295typedef struct { 296 int8_t code_; 297 int8_t extra_bits_; 298} VP8LPrefixCode; 299 300// These tables are derived using VP8LPrefixEncodeNoLUT. 301extern const VP8LPrefixCode kPrefixEncodeCode[PREFIX_LOOKUP_IDX_MAX]; 302extern const uint8_t kPrefixEncodeExtraBitsValue[PREFIX_LOOKUP_IDX_MAX]; 303static WEBP_INLINE void VP8LPrefixEncodeBits(int distance, int* const code, 304 int* const extra_bits) { 305 if (distance < PREFIX_LOOKUP_IDX_MAX) { 306 const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance]; 307 *code = prefix_code.code_; 308 *extra_bits = prefix_code.extra_bits_; 309 } else { 310 VP8LPrefixEncodeBitsNoLUT(distance, code, extra_bits); 311 } 312} 313 314static WEBP_INLINE void VP8LPrefixEncode(int distance, int* const code, 315 int* const extra_bits, 316 int* const extra_bits_value) { 317 if (distance < PREFIX_LOOKUP_IDX_MAX) { 318 const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance]; 319 *code = prefix_code.code_; 320 *extra_bits = prefix_code.extra_bits_; 321 *extra_bits_value = kPrefixEncodeExtraBitsValue[distance]; 322 } else { 323 VP8LPrefixEncodeNoLUT(distance, code, extra_bits, extra_bits_value); 324 } 325} 326 327// In-place difference of each component with mod 256. 328static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) { 329 const uint32_t alpha_and_green = 330 0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u); 331 const uint32_t red_and_blue = 332 0xff00ff00u + (a & 0x00ff00ffu) - (b & 0x00ff00ffu); 333 return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); 334} 335 336void VP8LBundleColorMap(const uint8_t* const row, int width, 337 int xbits, uint32_t* const dst); 338 339// Must be called before calling any of the above methods. 340void VP8LEncDspInit(void); 341 342//------------------------------------------------------------------------------ 343 344#ifdef __cplusplus 345} // extern "C" 346#endif 347 348#endif // WEBP_DSP_LOSSLESS_H_ 349