// Copyright 2011 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. // ----------------------------------------------------------------------------- // // Speed-critical functions. // // Author: Skal (pascal.massimino@gmail.com) #ifndef WEBP_DSP_DSP_H_ #define WEBP_DSP_DSP_H_ #ifdef HAVE_CONFIG_H #include "src/webp/config.h" #endif #include "src/webp/types.h" #ifdef __cplusplus extern "C" { #endif #define BPS 32 // this is the common stride for enc/dec //------------------------------------------------------------------------------ // CPU detection #if defined(__GNUC__) # define LOCAL_GCC_VERSION ((__GNUC__ << 8) | __GNUC_MINOR__) # define LOCAL_GCC_PREREQ(maj, min) \ (LOCAL_GCC_VERSION >= (((maj) << 8) | (min))) #else # define LOCAL_GCC_VERSION 0 # define LOCAL_GCC_PREREQ(maj, min) 0 #endif #if defined(__clang__) # define LOCAL_CLANG_VERSION ((__clang_major__ << 8) | __clang_minor__) # define LOCAL_CLANG_PREREQ(maj, min) \ (LOCAL_CLANG_VERSION >= (((maj) << 8) | (min))) #else # define LOCAL_CLANG_VERSION 0 # define LOCAL_CLANG_PREREQ(maj, min) 0 #endif #ifndef __has_builtin # define __has_builtin(x) 0 #endif // for now, none of the optimizations below are available in emscripten #if !defined(EMSCRIPTEN) #if defined(_MSC_VER) && _MSC_VER > 1310 && \ (defined(_M_X64) || defined(_M_IX86)) #define WEBP_MSC_SSE2 // Visual C++ SSE2 targets #endif #if defined(_MSC_VER) && _MSC_VER >= 1500 && \ (defined(_M_X64) || defined(_M_IX86)) #define WEBP_MSC_SSE41 // Visual C++ SSE4.1 targets #endif // WEBP_HAVE_* are used to indicate the presence of the instruction set in dsp // files without intrinsics, allowing the corresponding Init() to be called. // Files containing intrinsics will need to be built targeting the instruction // set so should succeed on one of the earlier tests. #if defined(__SSE2__) || defined(WEBP_MSC_SSE2) || defined(WEBP_HAVE_SSE2) #define WEBP_USE_SSE2 #endif #if defined(__SSE4_1__) || defined(WEBP_MSC_SSE41) || defined(WEBP_HAVE_SSE41) #define WEBP_USE_SSE41 #endif #if defined(__AVX2__) || defined(WEBP_HAVE_AVX2) #define WEBP_USE_AVX2 #endif // The intrinsics currently cause compiler errors with arm-nacl-gcc and the // inline assembly would need to be modified for use with Native Client. #if (defined(__ARM_NEON__) || \ defined(__aarch64__) || defined(WEBP_HAVE_NEON)) && \ !defined(__native_client__) #define WEBP_USE_NEON #endif #if !defined(WEBP_USE_NEON) && defined(__ANDROID__) && \ defined(__ARM_ARCH_7A__) && defined(HAVE_CPU_FEATURES_H) #define WEBP_ANDROID_NEON // Android targets that may have NEON #define WEBP_USE_NEON #endif #if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_M_ARM) #define WEBP_USE_NEON #define WEBP_USE_INTRINSICS #endif #if defined(__mips__) && !defined(__mips64) && \ defined(__mips_isa_rev) && (__mips_isa_rev >= 1) && (__mips_isa_rev < 6) #define WEBP_USE_MIPS32 #if (__mips_isa_rev >= 2) #define WEBP_USE_MIPS32_R2 #if defined(__mips_dspr2) || (defined(__mips_dsp_rev) && __mips_dsp_rev >= 2) #define WEBP_USE_MIPS_DSP_R2 #endif #endif #endif #if defined(__mips_msa) && defined(__mips_isa_rev) && (__mips_isa_rev >= 5) #define WEBP_USE_MSA #endif #endif /* EMSCRIPTEN */ #ifndef WEBP_DSP_OMIT_C_CODE #define WEBP_DSP_OMIT_C_CODE 1 #endif #if (defined(__aarch64__) || defined(__ARM_NEON__)) && WEBP_DSP_OMIT_C_CODE #define WEBP_NEON_OMIT_C_CODE 1 #else #define WEBP_NEON_OMIT_C_CODE 0 #endif #if !(LOCAL_CLANG_PREREQ(3,8) || LOCAL_GCC_PREREQ(4,8) || defined(__aarch64__)) #define WEBP_NEON_WORK_AROUND_GCC 1 #else #define WEBP_NEON_WORK_AROUND_GCC 0 #endif // This macro prevents thread_sanitizer from reporting known concurrent writes. #define WEBP_TSAN_IGNORE_FUNCTION #if defined(__has_feature) #if __has_feature(thread_sanitizer) #undef WEBP_TSAN_IGNORE_FUNCTION #define WEBP_TSAN_IGNORE_FUNCTION __attribute__((no_sanitize_thread)) #endif #endif #define WEBP_UBSAN_IGNORE_UNDEF #define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW #if defined(__clang__) && defined(__has_attribute) #if __has_attribute(no_sanitize) // This macro prevents the undefined behavior sanitizer from reporting // failures. This is only meant to silence unaligned loads on platforms that // are known to support them. #undef WEBP_UBSAN_IGNORE_UNDEF #define WEBP_UBSAN_IGNORE_UNDEF \ __attribute__((no_sanitize("undefined"))) // This macro prevents the undefined behavior sanitizer from reporting // failures related to unsigned integer overflows. This is only meant to // silence cases where this well defined behavior is expected. #undef WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW #define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW \ __attribute__((no_sanitize("unsigned-integer-overflow"))) #endif #endif // Regularize the definition of WEBP_SWAP_16BIT_CSP (backward compatibility) #if !defined(WEBP_SWAP_16BIT_CSP) #define WEBP_SWAP_16BIT_CSP 0 #endif typedef enum { kSSE2, kSSE3, kSlowSSSE3, // special feature for slow SSSE3 architectures kSSE4_1, kAVX, kAVX2, kNEON, kMIPS32, kMIPSdspR2, kMSA } CPUFeature; // returns true if the CPU supports the feature. typedef int (*VP8CPUInfo)(CPUFeature feature); WEBP_EXTERN VP8CPUInfo VP8GetCPUInfo; //------------------------------------------------------------------------------ // Init stub generator // Defines an init function stub to ensure each module exposes a symbol, // avoiding a compiler warning. #define WEBP_DSP_INIT_STUB(func) \ extern void func(void); \ WEBP_TSAN_IGNORE_FUNCTION void func(void) {} //------------------------------------------------------------------------------ // Encoding // Transforms // VP8Idct: Does one of two inverse transforms. If do_two is set, the transforms // will be done for (ref, in, dst) and (ref + 4, in + 16, dst + 4). typedef void (*VP8Idct)(const uint8_t* ref, const int16_t* in, uint8_t* dst, int do_two); typedef void (*VP8Fdct)(const uint8_t* src, const uint8_t* ref, int16_t* out); typedef void (*VP8WHT)(const int16_t* in, int16_t* out); extern VP8Idct VP8ITransform; extern VP8Fdct VP8FTransform; extern VP8Fdct VP8FTransform2; // performs two transforms at a time extern VP8WHT VP8FTransformWHT; // Predictions // *dst is the destination block. *top and *left can be NULL. typedef void (*VP8IntraPreds)(uint8_t *dst, const uint8_t* left, const uint8_t* top); typedef void (*VP8Intra4Preds)(uint8_t *dst, const uint8_t* top); extern VP8Intra4Preds VP8EncPredLuma4; extern VP8IntraPreds VP8EncPredLuma16; extern VP8IntraPreds VP8EncPredChroma8; typedef int (*VP8Metric)(const uint8_t* pix, const uint8_t* ref); extern VP8Metric VP8SSE16x16, VP8SSE16x8, VP8SSE8x8, VP8SSE4x4; typedef int (*VP8WMetric)(const uint8_t* pix, const uint8_t* ref, const uint16_t* const weights); // The weights for VP8TDisto4x4 and VP8TDisto16x16 contain a row-major // 4 by 4 symmetric matrix. extern VP8WMetric VP8TDisto4x4, VP8TDisto16x16; // Compute the average (DC) of four 4x4 blocks. // Each sub-4x4 block #i sum is stored in dc[i]. typedef void (*VP8MeanMetric)(const uint8_t* ref, uint32_t dc[4]); extern VP8MeanMetric VP8Mean16x4; typedef void (*VP8BlockCopy)(const uint8_t* src, uint8_t* dst); extern VP8BlockCopy VP8Copy4x4; extern VP8BlockCopy VP8Copy16x8; // Quantization struct VP8Matrix; // forward declaration typedef int (*VP8QuantizeBlock)(int16_t in[16], int16_t out[16], const struct VP8Matrix* const mtx); // Same as VP8QuantizeBlock, but quantizes two consecutive blocks. typedef int (*VP8Quantize2Blocks)(int16_t in[32], int16_t out[32], const struct VP8Matrix* const mtx); extern VP8QuantizeBlock VP8EncQuantizeBlock; extern VP8Quantize2Blocks VP8EncQuantize2Blocks; // specific to 2nd transform: typedef int (*VP8QuantizeBlockWHT)(int16_t in[16], int16_t out[16], const struct VP8Matrix* const mtx); extern VP8QuantizeBlockWHT VP8EncQuantizeBlockWHT; extern const int VP8DspScan[16 + 4 + 4]; // Collect histogram for susceptibility calculation. #define MAX_COEFF_THRESH 31 // size of histogram used by CollectHistogram. typedef struct { // We only need to store max_value and last_non_zero, not the distribution. int max_value; int last_non_zero; } VP8Histogram; typedef void (*VP8CHisto)(const uint8_t* ref, const uint8_t* pred, int start_block, int end_block, VP8Histogram* const histo); extern VP8CHisto VP8CollectHistogram; // General-purpose util function to help VP8CollectHistogram(). void VP8SetHistogramData(const int distribution[MAX_COEFF_THRESH + 1], VP8Histogram* const histo); // must be called before using any of the above void VP8EncDspInit(void); //------------------------------------------------------------------------------ // cost functions (encoding) extern const uint16_t VP8EntropyCost[256]; // 8bit fixed-point log(p) // approximate cost per level: extern const uint16_t VP8LevelFixedCosts[2047 /*MAX_LEVEL*/ + 1]; extern const uint8_t VP8EncBands[16 + 1]; struct VP8Residual; typedef void (*VP8SetResidualCoeffsFunc)(const int16_t* const coeffs, struct VP8Residual* const res); extern VP8SetResidualCoeffsFunc VP8SetResidualCoeffs; // Cost calculation function. typedef int (*VP8GetResidualCostFunc)(int ctx0, const struct VP8Residual* const res); extern VP8GetResidualCostFunc VP8GetResidualCost; // must be called before anything using the above void VP8EncDspCostInit(void); //------------------------------------------------------------------------------ // SSIM / PSNR utils // struct for accumulating statistical moments typedef struct { uint32_t w; // sum(w_i) : sum of weights uint32_t xm, ym; // sum(w_i * x_i), sum(w_i * y_i) uint32_t xxm, xym, yym; // sum(w_i * x_i * x_i), etc. } VP8DistoStats; // Compute the final SSIM value // The non-clipped version assumes stats->w = (2 * VP8_SSIM_KERNEL + 1)^2. double VP8SSIMFromStats(const VP8DistoStats* const stats); double VP8SSIMFromStatsClipped(const VP8DistoStats* const stats); #define VP8_SSIM_KERNEL 3 // total size of the kernel: 2 * VP8_SSIM_KERNEL + 1 typedef double (*VP8SSIMGetClippedFunc)(const uint8_t* src1, int stride1, const uint8_t* src2, int stride2, int xo, int yo, // center position int W, int H); // plane dimension #if !defined(WEBP_REDUCE_SIZE) // This version is called with the guarantee that you can load 8 bytes and // 8 rows at offset src1 and src2 typedef double (*VP8SSIMGetFunc)(const uint8_t* src1, int stride1, const uint8_t* src2, int stride2); extern VP8SSIMGetFunc VP8SSIMGet; // unclipped / unchecked extern VP8SSIMGetClippedFunc VP8SSIMGetClipped; // with clipping #endif #if !defined(WEBP_DISABLE_STATS) typedef uint32_t (*VP8AccumulateSSEFunc)(const uint8_t* src1, const uint8_t* src2, int len); extern VP8AccumulateSSEFunc VP8AccumulateSSE; #endif // must be called before using any of the above directly void VP8SSIMDspInit(void); //------------------------------------------------------------------------------ // Decoding typedef void (*VP8DecIdct)(const int16_t* coeffs, uint8_t* dst); // when doing two transforms, coeffs is actually int16_t[2][16]. typedef void (*VP8DecIdct2)(const int16_t* coeffs, uint8_t* dst, int do_two); extern VP8DecIdct2 VP8Transform; extern VP8DecIdct VP8TransformAC3; extern VP8DecIdct VP8TransformUV; extern VP8DecIdct VP8TransformDC; extern VP8DecIdct VP8TransformDCUV; extern VP8WHT VP8TransformWHT; // *dst is the destination block, with stride BPS. Boundary samples are // assumed accessible when needed. typedef void (*VP8PredFunc)(uint8_t* dst); extern VP8PredFunc VP8PredLuma16[/* NUM_B_DC_MODES */]; extern VP8PredFunc VP8PredChroma8[/* NUM_B_DC_MODES */]; extern VP8PredFunc VP8PredLuma4[/* NUM_BMODES */]; // clipping tables (for filtering) extern const int8_t* const VP8ksclip1; // clips [-1020, 1020] to [-128, 127] extern const int8_t* const VP8ksclip2; // clips [-112, 112] to [-16, 15] extern const uint8_t* const VP8kclip1; // clips [-255,511] to [0,255] extern const uint8_t* const VP8kabs0; // abs(x) for x in [-255,255] // must be called first void VP8InitClipTables(void); // simple filter (only for luma) typedef void (*VP8SimpleFilterFunc)(uint8_t* p, int stride, int thresh); extern VP8SimpleFilterFunc VP8SimpleVFilter16; extern VP8SimpleFilterFunc VP8SimpleHFilter16; extern VP8SimpleFilterFunc VP8SimpleVFilter16i; // filter 3 inner edges extern VP8SimpleFilterFunc VP8SimpleHFilter16i; // regular filter (on both macroblock edges and inner edges) typedef void (*VP8LumaFilterFunc)(uint8_t* luma, int stride, int thresh, int ithresh, int hev_t); typedef void (*VP8ChromaFilterFunc)(uint8_t* u, uint8_t* v, int stride, int thresh, int ithresh, int hev_t); // on outer edge extern VP8LumaFilterFunc VP8VFilter16; extern VP8LumaFilterFunc VP8HFilter16; extern VP8ChromaFilterFunc VP8VFilter8; extern VP8ChromaFilterFunc VP8HFilter8; // on inner edge extern VP8LumaFilterFunc VP8VFilter16i; // filtering 3 inner edges altogether extern VP8LumaFilterFunc VP8HFilter16i; extern VP8ChromaFilterFunc VP8VFilter8i; // filtering u and v altogether extern VP8ChromaFilterFunc VP8HFilter8i; // Dithering. Combines dithering values (centered around 128) with dst[], // according to: dst[] = clip(dst[] + (((dither[]-128) + 8) >> 4) #define VP8_DITHER_DESCALE 4 #define VP8_DITHER_DESCALE_ROUNDER (1 << (VP8_DITHER_DESCALE - 1)) #define VP8_DITHER_AMP_BITS 7 #define VP8_DITHER_AMP_CENTER (1 << VP8_DITHER_AMP_BITS) extern void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst, int dst_stride); // must be called before anything using the above void VP8DspInit(void); //------------------------------------------------------------------------------ // WebP I/O #define FANCY_UPSAMPLING // undefined to remove fancy upsampling support // Convert a pair of y/u/v lines together to the output rgb/a colorspace. // bottom_y can be NULL if only one line of output is needed (at top/bottom). typedef void (*WebPUpsampleLinePairFunc)( const uint8_t* top_y, const uint8_t* bottom_y, const uint8_t* top_u, const uint8_t* top_v, const uint8_t* cur_u, const uint8_t* cur_v, uint8_t* top_dst, uint8_t* bottom_dst, int len); #ifdef FANCY_UPSAMPLING // Fancy upsampling functions to convert YUV to RGB(A) modes extern WebPUpsampleLinePairFunc WebPUpsamplers[/* MODE_LAST */]; #endif // FANCY_UPSAMPLING // Per-row point-sampling methods. typedef void (*WebPSamplerRowFunc)(const uint8_t* y, const uint8_t* u, const uint8_t* v, uint8_t* dst, int len); // Generic function to apply 'WebPSamplerRowFunc' to the whole plane: void WebPSamplerProcessPlane(const uint8_t* y, int y_stride, const uint8_t* u, const uint8_t* v, int uv_stride, uint8_t* dst, int dst_stride, int width, int height, WebPSamplerRowFunc func); // Sampling functions to convert rows of YUV to RGB(A) extern WebPSamplerRowFunc WebPSamplers[/* MODE_LAST */]; // General function for converting two lines of ARGB or RGBA. // 'alpha_is_last' should be true if 0xff000000 is stored in memory as // as 0x00, 0x00, 0x00, 0xff (little endian). WebPUpsampleLinePairFunc WebPGetLinePairConverter(int alpha_is_last); // YUV444->RGB converters typedef void (*WebPYUV444Converter)(const uint8_t* y, const uint8_t* u, const uint8_t* v, uint8_t* dst, int len); extern WebPYUV444Converter WebPYUV444Converters[/* MODE_LAST */]; // Must be called before using the WebPUpsamplers[] (and for premultiplied // colorspaces like rgbA, rgbA4444, etc) void WebPInitUpsamplers(void); // Must be called before using WebPSamplers[] void WebPInitSamplers(void); // Must be called before using WebPYUV444Converters[] void WebPInitYUV444Converters(void); //------------------------------------------------------------------------------ // ARGB -> YUV converters // Convert ARGB samples to luma Y. extern void (*WebPConvertARGBToY)(const uint32_t* argb, uint8_t* y, int width); // Convert ARGB samples to U/V with downsampling. do_store should be '1' for // even lines and '0' for odd ones. 'src_width' is the original width, not // the U/V one. extern void (*WebPConvertARGBToUV)(const uint32_t* argb, uint8_t* u, uint8_t* v, int src_width, int do_store); // Convert a row of accumulated (four-values) of rgba32 toward U/V extern void (*WebPConvertRGBA32ToUV)(const uint16_t* rgb, uint8_t* u, uint8_t* v, int width); // Convert RGB or BGR to Y extern void (*WebPConvertRGB24ToY)(const uint8_t* rgb, uint8_t* y, int width); extern void (*WebPConvertBGR24ToY)(const uint8_t* bgr, uint8_t* y, int width); // used for plain-C fallback. extern void WebPConvertARGBToUV_C(const uint32_t* argb, uint8_t* u, uint8_t* v, int src_width, int do_store); extern void WebPConvertRGBA32ToUV_C(const uint16_t* rgb, uint8_t* u, uint8_t* v, int width); // utilities for accurate RGB->YUV conversion extern uint64_t (*WebPSharpYUVUpdateY)(const uint16_t* src, const uint16_t* ref, uint16_t* dst, int len); extern void (*WebPSharpYUVUpdateRGB)(const int16_t* src, const int16_t* ref, int16_t* dst, int len); extern void (*WebPSharpYUVFilterRow)(const int16_t* A, const int16_t* B, int len, const uint16_t* best_y, uint16_t* out); // Must be called before using the above. void WebPInitConvertARGBToYUV(void); //------------------------------------------------------------------------------ // Rescaler struct WebPRescaler; // Import a row of data and save its contribution in the rescaler. // 'channel' denotes the channel number to be imported. 'Expand' corresponds to // the wrk->x_expand case. Otherwise, 'Shrink' is to be used. typedef void (*WebPRescalerImportRowFunc)(struct WebPRescaler* const wrk, const uint8_t* src); extern WebPRescalerImportRowFunc WebPRescalerImportRowExpand; extern WebPRescalerImportRowFunc WebPRescalerImportRowShrink; // Export one row (starting at x_out position) from rescaler. // 'Expand' corresponds to the wrk->y_expand case. // Otherwise 'Shrink' is to be used typedef void (*WebPRescalerExportRowFunc)(struct WebPRescaler* const wrk); extern WebPRescalerExportRowFunc WebPRescalerExportRowExpand; extern WebPRescalerExportRowFunc WebPRescalerExportRowShrink; // Plain-C implementation, as fall-back. extern void WebPRescalerImportRowExpand_C(struct WebPRescaler* const wrk, const uint8_t* src); extern void WebPRescalerImportRowShrink_C(struct WebPRescaler* const wrk, const uint8_t* src); extern void WebPRescalerExportRowExpand_C(struct WebPRescaler* const wrk); extern void WebPRescalerExportRowShrink_C(struct WebPRescaler* const wrk); // Main entry calls: extern void WebPRescalerImportRow(struct WebPRescaler* const wrk, const uint8_t* src); // Export one row (starting at x_out position) from rescaler. extern void WebPRescalerExportRow(struct WebPRescaler* const wrk); // Must be called first before using the above. void WebPRescalerDspInit(void); //------------------------------------------------------------------------------ // Utilities for processing transparent channel. // Apply alpha pre-multiply on an rgba, bgra or argb plane of size w * h. // alpha_first should be 0 for argb, 1 for rgba or bgra (where alpha is last). extern void (*WebPApplyAlphaMultiply)( uint8_t* rgba, int alpha_first, int w, int h, int stride); // Same, buf specifically for RGBA4444 format extern void (*WebPApplyAlphaMultiply4444)( uint8_t* rgba4444, int w, int h, int stride); // Dispatch the values from alpha[] plane to the ARGB destination 'dst'. // Returns true if alpha[] plane has non-trivial values different from 0xff. extern int (*WebPDispatchAlpha)(const uint8_t* alpha, int alpha_stride, int width, int height, uint8_t* dst, int dst_stride); // Transfer packed 8b alpha[] values to green channel in dst[], zero'ing the // A/R/B values. 'dst_stride' is the stride for dst[] in uint32_t units. extern void (*WebPDispatchAlphaToGreen)(const uint8_t* alpha, int alpha_stride, int width, int height, uint32_t* dst, int dst_stride); // Extract the alpha values from 32b values in argb[] and pack them into alpha[] // (this is the opposite of WebPDispatchAlpha). // Returns true if there's only trivial 0xff alpha values. extern int (*WebPExtractAlpha)(const uint8_t* argb, int argb_stride, int width, int height, uint8_t* alpha, int alpha_stride); // Extract the green values from 32b values in argb[] and pack them into alpha[] // (this is the opposite of WebPDispatchAlphaToGreen). extern void (*WebPExtractGreen)(const uint32_t* argb, uint8_t* alpha, int size); // Pre-Multiply operation transforms x into x * A / 255 (where x=Y,R,G or B). // Un-Multiply operation transforms x into x * 255 / A. // Pre-Multiply or Un-Multiply (if 'inverse' is true) argb values in a row. extern void (*WebPMultARGBRow)(uint32_t* const ptr, int width, int inverse); // Same a WebPMultARGBRow(), but for several rows. void WebPMultARGBRows(uint8_t* ptr, int stride, int width, int num_rows, int inverse); // Same for a row of single values, with side alpha values. extern void (*WebPMultRow)(uint8_t* const ptr, const uint8_t* const alpha, int width, int inverse); // Same a WebPMultRow(), but for several 'num_rows' rows. void WebPMultRows(uint8_t* ptr, int stride, const uint8_t* alpha, int alpha_stride, int width, int num_rows, int inverse); // Plain-C versions, used as fallback by some implementations. void WebPMultRow_C(uint8_t* const ptr, const uint8_t* const alpha, int width, int inverse); void WebPMultARGBRow_C(uint32_t* const ptr, int width, int inverse); // RGB packing function. 'step' can be 3 or 4. r/g/b input is rgb or bgr order. extern void (*WebPPackRGB)(const uint8_t* r, const uint8_t* g, const uint8_t* b, int len, int step, uint32_t* out); // This function returns true if src[i] contains a value different from 0xff. extern int (*WebPHasAlpha8b)(const uint8_t* src, int length); // This function returns true if src[4*i] contains a value different from 0xff. extern int (*WebPHasAlpha32b)(const uint8_t* src, int length); // To be called first before using the above. void WebPInitAlphaProcessing(void); //------------------------------------------------------------------------------ // Filter functions typedef enum { // Filter types. WEBP_FILTER_NONE = 0, WEBP_FILTER_HORIZONTAL, WEBP_FILTER_VERTICAL, WEBP_FILTER_GRADIENT, WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1, // end marker WEBP_FILTER_BEST, // meta-types WEBP_FILTER_FAST } WEBP_FILTER_TYPE; typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height, int stride, uint8_t* out); // In-place un-filtering. // Warning! 'prev_line' pointer can be equal to 'cur_line' or 'preds'. typedef void (*WebPUnfilterFunc)(const uint8_t* prev_line, const uint8_t* preds, uint8_t* cur_line, int width); // Filter the given data using the given predictor. // 'in' corresponds to a 2-dimensional pixel array of size (stride * height) // in raster order. // 'stride' is number of bytes per scan line (with possible padding). // 'out' should be pre-allocated. extern WebPFilterFunc WebPFilters[WEBP_FILTER_LAST]; // In-place reconstruct the original data from the given filtered data. // The reconstruction will be done for 'num_rows' rows starting from 'row' // (assuming rows upto 'row - 1' are already reconstructed). extern WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST]; // To be called first before using the above. void VP8FiltersInit(void); #ifdef __cplusplus } // extern "C" #endif #endif /* WEBP_DSP_DSP_H_ */