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 (at) gmail.com) 13 // Jyrki Alakuijala (jyrki (at) 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 25 extern "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 35 typedef uint32_t (*VP8LPredictorFunc)(uint32_t left, const uint32_t* const top); 36 extern VP8LPredictorFunc VP8LPredictors[16]; 37 38 typedef void (*VP8LProcessBlueAndRedFunc)(uint32_t* argb_data, int num_pixels); 39 extern VP8LProcessBlueAndRedFunc VP8LAddGreenToBlueAndRed; 40 41 typedef 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; 48 typedef void (*VP8LTransformColorFunc)(const VP8LMultipliers* const m, 49 uint32_t* argb_data, int num_pixels); 50 extern VP8LTransformColorFunc VP8LTransformColorInverse; 51 52 struct 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). 58 void 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. 63 typedef void (*VP8LConvertFunc)(const uint32_t* src, int num_pixels, 64 uint8_t* dst); 65 extern VP8LConvertFunc VP8LConvertBGRAToRGB; 66 extern VP8LConvertFunc VP8LConvertBGRAToRGBA; 67 extern VP8LConvertFunc VP8LConvertBGRAToRGBA4444; 68 extern VP8LConvertFunc VP8LConvertBGRAToRGB565; 69 extern VP8LConvertFunc VP8LConvertBGRAToBGR; 70 71 // Converts from BGRA to other color spaces. 72 void 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. 76 static WEBP_INLINE uint32_t VP8GetARGBIndex(uint32_t idx) { 77 return (idx >> 8) & 0xff; 78 } 79 80 static WEBP_INLINE uint8_t VP8GetAlphaIndex(uint8_t idx) { 81 return idx; 82 } 83 84 static WEBP_INLINE uint32_t VP8GetARGBValue(uint32_t val) { 85 return val; 86 } 87 88 static WEBP_INLINE uint8_t VP8GetAlphaValue(uint32_t val) { 89 return (val >> 8) & 0xff; 90 } 91 92 typedef 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); 96 typedef 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); 100 101 extern VP8LMapARGBFunc VP8LMapColor32b; 102 extern 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'. 107 void 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 112 void VP8LTransformColorInverse_C(const VP8LMultipliers* const m, 113 uint32_t* data, int num_pixels); 114 115 void VP8LConvertBGRAToRGB_C(const uint32_t* src, int num_pixels, uint8_t* dst); 116 void VP8LConvertBGRAToRGBA_C(const uint32_t* src, int num_pixels, uint8_t* dst); 117 void VP8LConvertBGRAToRGBA4444_C(const uint32_t* src, 118 int num_pixels, uint8_t* dst); 119 void VP8LConvertBGRAToRGB565_C(const uint32_t* src, 120 int num_pixels, uint8_t* dst); 121 void VP8LConvertBGRAToBGR_C(const uint32_t* src, int num_pixels, uint8_t* dst); 122 void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels); 123 124 // Must be called before calling any of the above methods. 125 void VP8LDspInit(void); 126 127 //------------------------------------------------------------------------------ 128 // Encoding 129 130 extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed; 131 extern VP8LTransformColorFunc VP8LTransformColor; 132 typedef 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[]); 136 extern VP8LCollectColorBlueTransformsFunc VP8LCollectColorBlueTransforms; 137 138 typedef void (*VP8LCollectColorRedTransformsFunc)( 139 const uint32_t* argb, int stride, 140 int tile_width, int tile_height, 141 int green_to_red, int histo[]); 142 extern VP8LCollectColorRedTransformsFunc VP8LCollectColorRedTransforms; 143 144 // Expose some C-only fallback functions 145 void VP8LTransformColor_C(const VP8LMultipliers* const m, 146 uint32_t* data, int num_pixels); 147 void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels); 148 void VP8LCollectColorRedTransforms_C(const uint32_t* argb, int stride, 149 int tile_width, int tile_height, 150 int green_to_red, int histo[]); 151 void 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. 158 159 void 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); 162 163 void 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'. 170 static 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 256 186 extern const float kLog2Table[LOG_LOOKUP_IDX_MAX]; 187 extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX]; 188 typedef float (*VP8LFastLog2SlowFunc)(uint32_t v); 189 190 extern VP8LFastLog2SlowFunc VP8LFastLog2Slow; 191 extern VP8LFastLog2SlowFunc VP8LFastSLog2Slow; 192 193 static 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. 197 static 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. 203 204 typedef double (*VP8LCostFunc)(const uint32_t* population, int length); 205 typedef double (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y, 206 int length); 207 typedef float (*VP8LCombinedShannonEntropyFunc)(const int X[256], 208 const int Y[256]); 209 210 extern VP8LCostFunc VP8LExtraCost; 211 extern VP8LCostCombinedFunc VP8LExtraCostCombined; 212 extern VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy; 213 214 typedef 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; 218 219 typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X, 220 const uint32_t* Y, int length); 221 222 extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount; 223 224 typedef 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; 231 232 void 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. 237 void 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'. 242 void VP8LGetEntropyUnrefined(const uint32_t* const X, int length, 243 VP8LBitEntropy* const bit_entropy, 244 VP8LStreaks* const stats); 245 246 void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n, 247 VP8LBitEntropy* const entropy); 248 249 typedef 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. 255 extern GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper; 256 257 typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a, 258 const VP8LHistogram* const b, 259 VP8LHistogram* const out); 260 extern VP8LHistogramAddFunc VP8LHistogramAdd; 261 262 // ----------------------------------------------------------------------------- 263 // PrefixEncode() 264 265 static 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. 276 static 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 } 283 284 static 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 512 295 typedef struct { 296 int8_t code_; 297 int8_t extra_bits_; 298 } VP8LPrefixCode; 299 300 // These tables are derived using VP8LPrefixEncodeNoLUT. 301 extern const VP8LPrefixCode kPrefixEncodeCode[PREFIX_LOOKUP_IDX_MAX]; 302 extern const uint8_t kPrefixEncodeExtraBitsValue[PREFIX_LOOKUP_IDX_MAX]; 303 static 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 } 313 314 static 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. 328 static 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 } 335 336 void 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. 340 void VP8LEncDspInit(void); 341 342 //------------------------------------------------------------------------------ 343 344 #ifdef __cplusplus 345 } // extern "C" 346 #endif 347 348 #endif // WEBP_DSP_LOSSLESS_H_ 349
