250 lines
10 KiB
C
250 lines
10 KiB
C
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// Copyright 2012 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// Image transforms and color space conversion methods for lossless decoder.
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//
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// Authors: Vikas Arora (vikaas.arora@gmail.com)
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// Jyrki Alakuijala (jyrki@google.com)
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#ifndef WEBP_DSP_LOSSLESS_H_
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#define WEBP_DSP_LOSSLESS_H_
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#include "../webp/types.h"
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#include "../webp/decode.h"
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#include "../enc/histogram.h"
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#include "../utils/utils.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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//------------------------------------------------------------------------------
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// Signatures and generic function-pointers
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typedef uint32_t (*VP8LPredictorFunc)(uint32_t left, const uint32_t* const top);
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extern VP8LPredictorFunc VP8LPredictors[16];
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typedef void (*VP8LProcessBlueAndRedFunc)(uint32_t* argb_data, int num_pixels);
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extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed;
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extern VP8LProcessBlueAndRedFunc VP8LAddGreenToBlueAndRed;
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typedef struct {
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// Note: the members are uint8_t, so that any negative values are
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// automatically converted to "mod 256" values.
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uint8_t green_to_red_;
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uint8_t green_to_blue_;
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uint8_t red_to_blue_;
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} VP8LMultipliers;
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typedef void (*VP8LTransformColorFunc)(const VP8LMultipliers* const m,
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uint32_t* argb_data, int num_pixels);
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extern VP8LTransformColorFunc VP8LTransformColor;
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extern VP8LTransformColorFunc VP8LTransformColorInverse;
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typedef void (*VP8LConvertFunc)(const uint32_t* src, int num_pixels,
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uint8_t* dst);
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extern VP8LConvertFunc VP8LConvertBGRAToRGB;
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extern VP8LConvertFunc VP8LConvertBGRAToRGBA;
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extern VP8LConvertFunc VP8LConvertBGRAToRGBA4444;
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extern VP8LConvertFunc VP8LConvertBGRAToRGB565;
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extern VP8LConvertFunc VP8LConvertBGRAToBGR;
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// Expose some C-only fallback functions
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void VP8LTransformColor_C(const VP8LMultipliers* const m,
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uint32_t* data, int num_pixels);
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void VP8LTransformColorInverse_C(const VP8LMultipliers* const m,
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uint32_t* data, int num_pixels);
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void VP8LConvertBGRAToRGB_C(const uint32_t* src, int num_pixels, uint8_t* dst);
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void VP8LConvertBGRAToRGBA_C(const uint32_t* src, int num_pixels, uint8_t* dst);
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void VP8LConvertBGRAToRGBA4444_C(const uint32_t* src,
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int num_pixels, uint8_t* dst);
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void VP8LConvertBGRAToRGB565_C(const uint32_t* src,
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int num_pixels, uint8_t* dst);
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void VP8LConvertBGRAToBGR_C(const uint32_t* src, int num_pixels, uint8_t* dst);
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void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels);
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void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels);
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// Must be called before calling any of the above methods.
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void VP8LDspInit(void);
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//------------------------------------------------------------------------------
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// Image transforms.
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struct VP8LTransform; // Defined in dec/vp8li.h.
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// Performs inverse transform of data given transform information, start and end
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// rows. Transform will be applied to rows [row_start, row_end[.
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// The *in and *out pointers refer to source and destination data respectively
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// corresponding to the intermediate row (row_start).
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void VP8LInverseTransform(const struct VP8LTransform* const transform,
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int row_start, int row_end,
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const uint32_t* const in, uint32_t* const out);
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// Similar to the static method ColorIndexInverseTransform() that is part of
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// lossless.c, but used only for alpha decoding. It takes uint8_t (rather than
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// uint32_t) arguments for 'src' and 'dst'.
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void VP8LColorIndexInverseTransformAlpha(
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const struct VP8LTransform* const transform, int y_start, int y_end,
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const uint8_t* src, uint8_t* dst);
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void VP8LResidualImage(int width, int height, int bits,
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uint32_t* const argb, uint32_t* const argb_scratch,
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uint32_t* const image);
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void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
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uint32_t* const argb, uint32_t* image);
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//------------------------------------------------------------------------------
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// Color space conversion.
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// Converts from BGRA to other color spaces.
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void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels,
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WEBP_CSP_MODE out_colorspace, uint8_t* const rgba);
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//------------------------------------------------------------------------------
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// Misc methods.
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// Computes sampled size of 'size' when sampling using 'sampling bits'.
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static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size,
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uint32_t sampling_bits) {
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return (size + (1 << sampling_bits) - 1) >> sampling_bits;
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}
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// -----------------------------------------------------------------------------
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// Faster logarithm for integers. Small values use a look-up table.
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#define LOG_LOOKUP_IDX_MAX 256
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extern const float kLog2Table[LOG_LOOKUP_IDX_MAX];
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extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX];
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typedef float (*VP8LFastLog2SlowFunc)(uint32_t v);
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extern VP8LFastLog2SlowFunc VP8LFastLog2Slow;
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extern VP8LFastLog2SlowFunc VP8LFastSLog2Slow;
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static WEBP_INLINE float VP8LFastLog2(uint32_t v) {
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return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v);
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}
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// Fast calculation of v * log2(v) for integer input.
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static WEBP_INLINE float VP8LFastSLog2(uint32_t v) {
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return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v);
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}
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// -----------------------------------------------------------------------------
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// Huffman-cost related functions.
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typedef double (*VP8LCostFunc)(const uint32_t* population, int length);
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typedef double (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y,
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int length);
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extern VP8LCostFunc VP8LExtraCost;
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extern VP8LCostCombinedFunc VP8LExtraCostCombined;
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typedef struct { // small struct to hold counters
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int counts[2]; // index: 0=zero steak, 1=non-zero streak
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int streaks[2][2]; // [zero/non-zero][streak<3 / streak>=3]
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} VP8LStreaks;
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typedef VP8LStreaks (*VP8LCostCountFunc)(const uint32_t* population,
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int length);
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typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X,
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const uint32_t* Y, int length);
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extern VP8LCostCountFunc VP8LHuffmanCostCount;
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extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
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typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a,
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const VP8LHistogram* const b,
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VP8LHistogram* const out);
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extern VP8LHistogramAddFunc VP8LHistogramAdd;
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// -----------------------------------------------------------------------------
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// PrefixEncode()
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static WEBP_INLINE int VP8LBitsLog2Ceiling(uint32_t n) {
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const int log_floor = BitsLog2Floor(n);
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if (n == (n & ~(n - 1))) // zero or a power of two.
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return log_floor;
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else
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return log_floor + 1;
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}
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// Splitting of distance and length codes into prefixes and
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// extra bits. The prefixes are encoded with an entropy code
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// while the extra bits are stored just as normal bits.
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static WEBP_INLINE void VP8LPrefixEncodeBitsNoLUT(int distance, int* const code,
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int* const extra_bits) {
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const int highest_bit = BitsLog2Floor(--distance);
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const int second_highest_bit = (distance >> (highest_bit - 1)) & 1;
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*extra_bits = highest_bit - 1;
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*code = 2 * highest_bit + second_highest_bit;
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}
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static WEBP_INLINE void VP8LPrefixEncodeNoLUT(int distance, int* const code,
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int* const extra_bits,
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int* const extra_bits_value) {
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const int highest_bit = BitsLog2Floor(--distance);
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const int second_highest_bit = (distance >> (highest_bit - 1)) & 1;
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*extra_bits = highest_bit - 1;
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*extra_bits_value = distance & ((1 << *extra_bits) - 1);
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*code = 2 * highest_bit + second_highest_bit;
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}
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#define PREFIX_LOOKUP_IDX_MAX 512
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typedef struct {
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int8_t code_;
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int8_t extra_bits_;
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} VP8LPrefixCode;
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// These tables are derived using VP8LPrefixEncodeNoLUT.
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extern const VP8LPrefixCode kPrefixEncodeCode[PREFIX_LOOKUP_IDX_MAX];
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extern const uint8_t kPrefixEncodeExtraBitsValue[PREFIX_LOOKUP_IDX_MAX];
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static WEBP_INLINE void VP8LPrefixEncodeBits(int distance, int* const code,
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int* const extra_bits) {
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if (distance < PREFIX_LOOKUP_IDX_MAX) {
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const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance];
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*code = prefix_code.code_;
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*extra_bits = prefix_code.extra_bits_;
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} else {
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VP8LPrefixEncodeBitsNoLUT(distance, code, extra_bits);
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}
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}
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static WEBP_INLINE void VP8LPrefixEncode(int distance, int* const code,
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int* const extra_bits,
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int* const extra_bits_value) {
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if (distance < PREFIX_LOOKUP_IDX_MAX) {
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const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance];
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*code = prefix_code.code_;
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*extra_bits = prefix_code.extra_bits_;
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*extra_bits_value = kPrefixEncodeExtraBitsValue[distance];
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} else {
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VP8LPrefixEncodeNoLUT(distance, code, extra_bits, extra_bits_value);
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}
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}
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// In-place difference of each component with mod 256.
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static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) {
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const uint32_t alpha_and_green =
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0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u);
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const uint32_t red_and_blue =
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0xff00ff00u + (a & 0x00ff00ffu) - (b & 0x00ff00ffu);
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return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu);
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}
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void VP8LBundleColorMap(const uint8_t* const row, int width,
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int xbits, uint32_t* const dst);
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//------------------------------------------------------------------------------
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // WEBP_DSP_LOSSLESS_H_
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