// Copyright 2012 Google Inc. All Rights Reserved. // // Use of this source code is governed by a BSD-style license // that can be found in the COPYING file in the root of the source // tree. An additional intellectual property rights grant can be found // in the file PATENTS. All contributing project authors may // be found in the AUTHORS file in the root of the source tree. // ----------------------------------------------------------------------------- // // Image transforms and color space conversion methods for lossless decoder. // // Authors: Vikas Arora (vikaas.arora@gmail.com) // Jyrki Alakuijala (jyrki@google.com) #ifndef WEBP_DSP_LOSSLESS_H_ #define WEBP_DSP_LOSSLESS_H_ #include "../webp/types.h" #include "../webp/decode.h" #include "../enc/histogram.h" #include "../utils/utils.h" #ifdef __cplusplus extern "C" { #endif #ifdef WEBP_EXPERIMENTAL_FEATURES #include "../enc/delta_palettization.h" #endif // WEBP_EXPERIMENTAL_FEATURES //------------------------------------------------------------------------------ // Decoding typedef uint32_t (*VP8LPredictorFunc)(uint32_t left, const uint32_t* const top); extern VP8LPredictorFunc VP8LPredictors[16]; typedef void (*VP8LProcessBlueAndRedFunc)(uint32_t* argb_data, int num_pixels); extern VP8LProcessBlueAndRedFunc VP8LAddGreenToBlueAndRed; 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_; } VP8LMultipliers; typedef void (*VP8LTransformColorFunc)(const VP8LMultipliers* const m, uint32_t* argb_data, int num_pixels); extern VP8LTransformColorFunc VP8LTransformColorInverse; struct VP8LTransform; // Defined in dec/vp8li.h. // Performs inverse transform of data given transform information, start and end // rows. Transform will be applied to rows [row_start, row_end[. // The *in and *out pointers refer to source and destination data respectively // corresponding to the intermediate row (row_start). void VP8LInverseTransform(const struct VP8LTransform* const transform, int row_start, int row_end, const uint32_t* const in, uint32_t* const out); // Color space conversion. typedef void (*VP8LConvertFunc)(const uint32_t* src, int num_pixels, uint8_t* dst); extern VP8LConvertFunc VP8LConvertBGRAToRGB; extern VP8LConvertFunc VP8LConvertBGRAToRGBA; extern VP8LConvertFunc VP8LConvertBGRAToRGBA4444; extern VP8LConvertFunc VP8LConvertBGRAToRGB565; extern VP8LConvertFunc VP8LConvertBGRAToBGR; // Converts from BGRA to other color spaces. void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels, WEBP_CSP_MODE out_colorspace, uint8_t* const rgba); // color mapping related functions. static WEBP_INLINE uint32_t VP8GetARGBIndex(uint32_t idx) { return (idx >> 8) & 0xff; } static WEBP_INLINE uint8_t VP8GetAlphaIndex(uint8_t idx) { return idx; } static WEBP_INLINE uint32_t VP8GetARGBValue(uint32_t val) { return val; } static WEBP_INLINE uint8_t VP8GetAlphaValue(uint32_t val) { return (val >> 8) & 0xff; } typedef void (*VP8LMapARGBFunc)(const uint32_t* src, const uint32_t* const color_map, uint32_t* dst, int y_start, int y_end, int width); typedef void (*VP8LMapAlphaFunc)(const uint8_t* src, const uint32_t* const color_map, uint8_t* dst, int y_start, int y_end, int width); extern VP8LMapARGBFunc VP8LMapColor32b; extern VP8LMapAlphaFunc VP8LMapColor8b; // Similar to the static method ColorIndexInverseTransform() that is part of // lossless.c, but used only for alpha decoding. It takes uint8_t (rather than // uint32_t) arguments for 'src' and 'dst'. void VP8LColorIndexInverseTransformAlpha( const struct VP8LTransform* const transform, int y_start, int y_end, const uint8_t* src, uint8_t* dst); // Expose some C-only fallback functions void VP8LTransformColorInverse_C(const VP8LMultipliers* const m, uint32_t* data, int num_pixels); void VP8LConvertBGRAToRGB_C(const uint32_t* src, int num_pixels, uint8_t* dst); void VP8LConvertBGRAToRGBA_C(const uint32_t* src, int num_pixels, uint8_t* dst); void VP8LConvertBGRAToRGBA4444_C(const uint32_t* src, int num_pixels, uint8_t* dst); void VP8LConvertBGRAToRGB565_C(const uint32_t* src, int num_pixels, uint8_t* dst); void VP8LConvertBGRAToBGR_C(const uint32_t* src, int num_pixels, uint8_t* dst); void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels); // Must be called before calling any of the above methods. void VP8LDspInit(void); //------------------------------------------------------------------------------ // Encoding extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed; extern VP8LTransformColorFunc VP8LTransformColor; typedef void (*VP8LCollectColorBlueTransformsFunc)( const uint32_t* argb, int stride, int tile_width, int tile_height, int green_to_blue, int red_to_blue, int histo[]); extern VP8LCollectColorBlueTransformsFunc VP8LCollectColorBlueTransforms; typedef void (*VP8LCollectColorRedTransformsFunc)( const uint32_t* argb, int stride, int tile_width, int tile_height, int green_to_red, int histo[]); extern VP8LCollectColorRedTransformsFunc VP8LCollectColorRedTransforms; // Expose some C-only fallback functions void VP8LTransformColor_C(const VP8LMultipliers* const m, uint32_t* data, int num_pixels); void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels); void VP8LCollectColorRedTransforms_C(const uint32_t* argb, int stride, int tile_width, int tile_height, int green_to_red, int histo[]); void VP8LCollectColorBlueTransforms_C(const uint32_t* argb, int stride, int tile_width, int tile_height, int green_to_blue, int red_to_blue, int histo[]); //------------------------------------------------------------------------------ // Image transforms. void VP8LResidualImage(int width, int height, int bits, int low_effort, uint32_t* const argb, uint32_t* const argb_scratch, uint32_t* const image, int near_lossless, int exact, int used_subtract_green); void VP8LColorSpaceTransform(int width, int height, int bits, int quality, uint32_t* const argb, uint32_t* image); //------------------------------------------------------------------------------ // Misc methods. // Computes sampled size of 'size' when sampling using 'sampling bits'. static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size, uint32_t sampling_bits) { return (size + (1 << sampling_bits) - 1) >> sampling_bits; } // Converts near lossless quality into max number of bits shaved off. static WEBP_INLINE int VP8LNearLosslessBits(int near_lossless_quality) { // 100 -> 0 // 80..99 -> 1 // 60..79 -> 2 // 40..59 -> 3 // 20..39 -> 4 // 0..19 -> 5 return 5 - near_lossless_quality / 20; } // ----------------------------------------------------------------------------- // Faster logarithm for integers. Small values use a look-up table. // The threshold till approximate version of log_2 can be used. // Practically, we can get rid of the call to log() as the two values match to // very high degree (the ratio of these two is 0.99999x). // Keeping a high threshold for now. #define APPROX_LOG_WITH_CORRECTION_MAX 65536 #define APPROX_LOG_MAX 4096 #define LOG_2_RECIPROCAL 1.44269504088896338700465094007086 #define LOG_LOOKUP_IDX_MAX 256 extern const float kLog2Table[LOG_LOOKUP_IDX_MAX]; extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX]; typedef float (*VP8LFastLog2SlowFunc)(uint32_t v); extern VP8LFastLog2SlowFunc VP8LFastLog2Slow; extern VP8LFastLog2SlowFunc VP8LFastSLog2Slow; static WEBP_INLINE float VP8LFastLog2(uint32_t v) { return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v); } // Fast calculation of v * log2(v) for integer input. static WEBP_INLINE float VP8LFastSLog2(uint32_t v) { return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v); } // ----------------------------------------------------------------------------- // Huffman-cost related functions. typedef double (*VP8LCostFunc)(const uint32_t* population, int length); typedef double (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y, int length); typedef float (*VP8LCombinedShannonEntropyFunc)(const int X[256], const int Y[256]); extern VP8LCostFunc VP8LExtraCost; extern VP8LCostCombinedFunc VP8LExtraCostCombined; extern VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy; typedef struct { // small struct to hold counters int counts[2]; // index: 0=zero steak, 1=non-zero streak int streaks[2][2]; // [zero/non-zero][streak<3 / streak>=3] } VP8LStreaks; typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X, const uint32_t* Y, int length); extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount; typedef struct { // small struct to hold bit entropy results double entropy; // entropy uint32_t sum; // sum of the population int nonzeros; // number of non-zero elements in the population uint32_t max_val; // maximum value in the population uint32_t nonzero_code; // index of the last non-zero in the population } VP8LBitEntropy; void VP8LBitEntropyInit(VP8LBitEntropy* const entropy); // Get the combined symbol bit entropy and Huffman cost stats for the // distributions 'X' and 'Y'. Those results can then be refined according to // codec specific heuristics. void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X, const uint32_t* const Y, int length, VP8LBitEntropy* const bit_entropy, VP8LStreaks* const stats); // Get the entropy for the distribution 'X'. void VP8LGetEntropyUnrefined(const uint32_t* const X, int length, VP8LBitEntropy* const bit_entropy, VP8LStreaks* const stats); void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n, VP8LBitEntropy* const entropy); typedef void (*GetEntropyUnrefinedHelperFunc)(uint32_t val, int i, uint32_t* const val_prev, int* const i_prev, VP8LBitEntropy* const bit_entropy, VP8LStreaks* const stats); // Internal function used by VP8LGet*EntropyUnrefined. extern GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper; typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a, const VP8LHistogram* const b, VP8LHistogram* const out); extern VP8LHistogramAddFunc VP8LHistogramAdd; // ----------------------------------------------------------------------------- // PrefixEncode() typedef int (*VP8LVectorMismatchFunc)(const uint32_t* const array1, const uint32_t* const array2, int length); // Returns the first index where array1 and array2 are different. extern VP8LVectorMismatchFunc VP8LVectorMismatch; static WEBP_INLINE int VP8LBitsLog2Ceiling(uint32_t n) { const int log_floor = BitsLog2Floor(n); if (n == (n & ~(n - 1))) // zero or a power of two. return log_floor; else return log_floor + 1; } // Splitting of distance and length codes into prefixes and // extra bits. The prefixes are encoded with an entropy code // while the extra bits are stored just as normal bits. static WEBP_INLINE void VP8LPrefixEncodeBitsNoLUT(int distance, int* const code, int* const extra_bits) { const int highest_bit = BitsLog2Floor(--distance); const int second_highest_bit = (distance >> (highest_bit - 1)) & 1; *extra_bits = highest_bit - 1; *code = 2 * highest_bit + second_highest_bit; } static WEBP_INLINE void VP8LPrefixEncodeNoLUT(int distance, int* const code, int* const extra_bits, int* const extra_bits_value) { const int highest_bit = BitsLog2Floor(--distance); const int second_highest_bit = (distance >> (highest_bit - 1)) & 1; *extra_bits = highest_bit - 1; *extra_bits_value = distance & ((1 << *extra_bits) - 1); *code = 2 * highest_bit + second_highest_bit; } #define PREFIX_LOOKUP_IDX_MAX 512 typedef struct { int8_t code_; int8_t extra_bits_; } VP8LPrefixCode; // These tables are derived using VP8LPrefixEncodeNoLUT. extern const VP8LPrefixCode kPrefixEncodeCode[PREFIX_LOOKUP_IDX_MAX]; extern const uint8_t kPrefixEncodeExtraBitsValue[PREFIX_LOOKUP_IDX_MAX]; static WEBP_INLINE void VP8LPrefixEncodeBits(int distance, int* const code, int* const extra_bits) { if (distance < PREFIX_LOOKUP_IDX_MAX) { const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance]; *code = prefix_code.code_; *extra_bits = prefix_code.extra_bits_; } else { VP8LPrefixEncodeBitsNoLUT(distance, code, extra_bits); } } static WEBP_INLINE void VP8LPrefixEncode(int distance, int* const code, int* const extra_bits, int* const extra_bits_value) { if (distance < PREFIX_LOOKUP_IDX_MAX) { const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance]; *code = prefix_code.code_; *extra_bits = prefix_code.extra_bits_; *extra_bits_value = kPrefixEncodeExtraBitsValue[distance]; } else { VP8LPrefixEncodeNoLUT(distance, code, extra_bits, extra_bits_value); } } // Sum of each component, mod 256. static WEBP_INLINE uint32_t VP8LAddPixels(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); return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); } // Difference of each component, mod 256. static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) { const uint32_t alpha_and_green = 0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u); const uint32_t red_and_blue = 0xff00ff00u + (a & 0x00ff00ffu) - (b & 0x00ff00ffu); return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); } void VP8LBundleColorMap(const uint8_t* const row, int width, int xbits, uint32_t* const dst); // Must be called before calling any of the above methods. void VP8LEncDspInit(void); //------------------------------------------------------------------------------ #ifdef __cplusplus } // extern "C" #endif #endif // WEBP_DSP_LOSSLESS_H_