| // 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 |
| |
| //------------------------------------------------------------------------------ |
| // Signatures and generic function-pointers |
| |
| 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 VP8LSubtractGreenFromBlueAndRed; |
| 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 VP8LTransformColor; |
| extern VP8LTransformColorFunc VP8LTransformColorInverse; |
| |
| 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; |
| |
| // Expose some C-only fallback functions |
| void VP8LTransformColor_C(const VP8LMultipliers* const m, |
| uint32_t* data, int num_pixels); |
| 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 VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels); |
| void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels); |
| |
| // Must be called before calling any of the above methods. |
| void VP8LDspInit(void); |
| |
| //------------------------------------------------------------------------------ |
| // Image transforms. |
| |
| 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); |
| |
| // 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); |
| |
| void VP8LResidualImage(int width, int height, int bits, |
| uint32_t* const argb, uint32_t* const argb_scratch, |
| uint32_t* const image); |
| |
| void VP8LColorSpaceTransform(int width, int height, int bits, int quality, |
| uint32_t* const argb, uint32_t* image); |
| |
| //------------------------------------------------------------------------------ |
| // Color space conversion. |
| |
| // 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); |
| |
| //------------------------------------------------------------------------------ |
| // 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; |
| } |
| |
| // ----------------------------------------------------------------------------- |
| // Faster logarithm for integers. Small values use a look-up table. |
| #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); |
| |
| extern VP8LCostFunc VP8LExtraCost; |
| extern VP8LCostCombinedFunc VP8LExtraCostCombined; |
| |
| 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 (*VP8LCostCountFunc)(const uint32_t* population, |
| int length); |
| typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X, |
| const uint32_t* Y, int length); |
| |
| extern VP8LCostCountFunc VP8LHuffmanCostCount; |
| extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount; |
| |
| typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a, |
| const VP8LHistogram* const b, |
| VP8LHistogram* const out); |
| extern VP8LHistogramAddFunc VP8LHistogramAdd; |
| |
| // ----------------------------------------------------------------------------- |
| // PrefixEncode() |
| |
| 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); |
| } |
| } |
| |
| // In-place difference of each component with 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); |
| |
| //------------------------------------------------------------------------------ |
| |
| #ifdef __cplusplus |
| } // extern "C" |
| #endif |
| |
| #endif // WEBP_DSP_LOSSLESS_H_ |