55414bc573
Note that there are two Godot-specific changes made to libwebp
for the javascript/HTML5 platform. They are documented in the
README.md.
(cherry picked from commit ee3cf211c6)
372 lines
15 KiB
C++
372 lines
15 KiB
C++
// 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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#ifdef WEBP_EXPERIMENTAL_FEATURES
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#include "../enc/delta_palettization.h"
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#endif // WEBP_EXPERIMENTAL_FEATURES
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//------------------------------------------------------------------------------
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// Decoding
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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 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 VP8LTransformColorInverse;
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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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// Color space conversion.
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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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// 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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// color mapping related functions.
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static WEBP_INLINE uint32_t VP8GetARGBIndex(uint32_t idx) {
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return (idx >> 8) & 0xff;
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}
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static WEBP_INLINE uint8_t VP8GetAlphaIndex(uint8_t idx) {
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return idx;
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}
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static WEBP_INLINE uint32_t VP8GetARGBValue(uint32_t val) {
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return val;
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}
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static WEBP_INLINE uint8_t VP8GetAlphaValue(uint32_t val) {
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return (val >> 8) & 0xff;
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}
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typedef void (*VP8LMapARGBFunc)(const uint32_t* src,
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const uint32_t* const color_map,
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uint32_t* dst, int y_start,
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int y_end, int width);
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typedef void (*VP8LMapAlphaFunc)(const uint8_t* src,
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const uint32_t* const color_map,
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uint8_t* dst, int y_start,
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int y_end, int width);
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extern VP8LMapARGBFunc VP8LMapColor32b;
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extern VP8LMapAlphaFunc VP8LMapColor8b;
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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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// Expose some C-only fallback functions
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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 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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// Encoding
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extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed;
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extern VP8LTransformColorFunc VP8LTransformColor;
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typedef void (*VP8LCollectColorBlueTransformsFunc)(
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const uint32_t* argb, int stride,
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int tile_width, int tile_height,
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int green_to_blue, int red_to_blue, int histo[]);
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extern VP8LCollectColorBlueTransformsFunc VP8LCollectColorBlueTransforms;
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typedef void (*VP8LCollectColorRedTransformsFunc)(
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const uint32_t* argb, int stride,
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int tile_width, int tile_height,
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int green_to_red, int histo[]);
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extern VP8LCollectColorRedTransformsFunc VP8LCollectColorRedTransforms;
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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 VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels);
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void VP8LCollectColorRedTransforms_C(const uint32_t* argb, int stride,
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int tile_width, int tile_height,
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int green_to_red, int histo[]);
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void VP8LCollectColorBlueTransforms_C(const uint32_t* argb, int stride,
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int tile_width, int tile_height,
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int green_to_blue, int red_to_blue,
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int histo[]);
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//------------------------------------------------------------------------------
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// Image transforms.
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void VP8LResidualImage(int width, int height, int bits, int low_effort,
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uint32_t* const argb, uint32_t* const argb_scratch,
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uint32_t* const image, int near_lossless, int exact,
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int used_subtract_green);
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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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// 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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// Converts near lossless quality into max number of bits shaved off.
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static WEBP_INLINE int VP8LNearLosslessBits(int near_lossless_quality) {
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// 100 -> 0
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// 80..99 -> 1
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// 60..79 -> 2
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// 40..59 -> 3
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// 20..39 -> 4
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// 0..19 -> 5
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return 5 - near_lossless_quality / 20;
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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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// The threshold till approximate version of log_2 can be used.
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// Practically, we can get rid of the call to log() as the two values match to
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// very high degree (the ratio of these two is 0.99999x).
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// Keeping a high threshold for now.
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#define APPROX_LOG_WITH_CORRECTION_MAX 65536
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#define APPROX_LOG_MAX 4096
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#define LOG_2_RECIPROCAL 1.44269504088896338700465094007086
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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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typedef float (*VP8LCombinedShannonEntropyFunc)(const int X[256],
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const int Y[256]);
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extern VP8LCostFunc VP8LExtraCost;
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extern VP8LCostCombinedFunc VP8LExtraCostCombined;
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extern VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy;
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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 (*VP8LCostCombinedCountFunc)(const uint32_t* X,
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const uint32_t* Y, int length);
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extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
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typedef struct { // small struct to hold bit entropy results
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double entropy; // entropy
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uint32_t sum; // sum of the population
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int nonzeros; // number of non-zero elements in the population
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uint32_t max_val; // maximum value in the population
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uint32_t nonzero_code; // index of the last non-zero in the population
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} VP8LBitEntropy;
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void VP8LBitEntropyInit(VP8LBitEntropy* const entropy);
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// Get the combined symbol bit entropy and Huffman cost stats for the
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// distributions 'X' and 'Y'. Those results can then be refined according to
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// codec specific heuristics.
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void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X,
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const uint32_t* const Y, int length,
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VP8LBitEntropy* const bit_entropy,
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VP8LStreaks* const stats);
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// Get the entropy for the distribution 'X'.
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void VP8LGetEntropyUnrefined(const uint32_t* const X, int length,
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VP8LBitEntropy* const bit_entropy,
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VP8LStreaks* const stats);
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void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n,
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VP8LBitEntropy* const entropy);
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typedef void (*GetEntropyUnrefinedHelperFunc)(uint32_t val, int i,
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uint32_t* const val_prev,
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int* const i_prev,
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VP8LBitEntropy* const bit_entropy,
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VP8LStreaks* const stats);
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// Internal function used by VP8LGet*EntropyUnrefined.
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extern GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper;
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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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typedef int (*VP8LVectorMismatchFunc)(const uint32_t* const array1,
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const uint32_t* const array2, int length);
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// Returns the first index where array1 and array2 are different.
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extern VP8LVectorMismatchFunc VP8LVectorMismatch;
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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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// Sum of each component, mod 256.
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static WEBP_INLINE uint32_t VP8LAddPixels(uint32_t a, uint32_t b) {
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const uint32_t alpha_and_green = (a & 0xff00ff00u) + (b & 0xff00ff00u);
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const uint32_t red_and_blue = (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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// Difference of each component, 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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// Must be called before calling any of the above methods.
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void VP8LEncDspInit(void);
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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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