// 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.

// -----------------------------------------------------------------------------

//

//   WebP encoder: internal header.

//

// Author: Skal (pascal.massimino@gmail.com)

#ifndef WEBP_ENC_VP8I_ENC_H_

#define WEBP_ENC_VP8I_ENC_H_

#include <string.h>  // for memcpy()

#include "src/dec/common_dec.h"

#include "src/dsp/cpu.h"

#include "src/dsp/dsp.h"

#include "src/utils/bit_writer_utils.h"

#include "src/utils/thread_utils.h"

#include "src/utils/utils.h"

#include "src/webp/encode.h"

#include "src/webp/types.h"

#ifdef __cplusplus

extern "C" {

#endif

//------------------------------------------------------------------------------

// Various defines and enums

// version numbers

#define ENC_MAJ_VERSION 1

#define ENC_MIN_VERSION 6

#define ENC_REV_VERSION 0

enum {

  MAX_LF_LEVELS = 64,       // Maximum loop filter level

  MAX_VARIABLE_LEVEL = 67,  // last (inclusive) level with variable cost

  MAX_LEVEL = 2047          // max level (note: max codable is 2047 + 67)

};

typedef enum {            // Rate-distortion optimization levels

  RD_OPT_NONE = 0,        // no rd-opt

  RD_OPT_BASIC = 1,       // basic scoring (no trellis)

  RD_OPT_TRELLIS = 2,     // perform trellis-quant on the final decision only

  RD_OPT_TRELLIS_ALL = 3  // trellis-quant for every scoring (much slower)

} VP8RDLevel;

// YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).

// The original or reconstructed samples can be accessed using VP8Scan[].

// The predicted blocks can be accessed using offsets to 'yuv_p' and

// the arrays VP8*ModeOffsets[].

// * YUV Samples area ('yuv_in'/'yuv_out'/'yuv_out2')

//   (see VP8Scan[] for accessing the blocks, along with

//   Y_OFF_ENC/U_OFF_ENC/V_OFF_ENC):

//             +----+----+

//  Y_OFF_ENC  |YYYY|UUVV|

//  U_OFF_ENC  |YYYY|UUVV|

//  V_OFF_ENC  |YYYY|....| <- 25% wasted U/V area

//             |YYYY|....|

//             +----+----+

// * Prediction area ('yuv_p', size = PRED_SIZE_ENC)

//   Intra16 predictions (16x16 block each, two per row):

//         |I16DC16|I16TM16|

//         |I16VE16|I16HE16|

//   Chroma U/V predictions (16x8 block each, two per row):

//         |C8DC8|C8TM8|

//         |C8VE8|C8HE8|

//   Intra 4x4 predictions (4x4 block each)

//         |I4DC4 I4TM4 I4VE4 I4HE4|I4RD4 I4VR4 I4LD4 I4VL4|

//         |I4HD4 I4HU4 I4TMP .....|.......................| <- ~31% wasted

#define YUV_SIZE_ENC (BPS * 16)

#define PRED_SIZE_ENC (32 * BPS + 16 * BPS + 8 * BPS)  // I16+Chroma+I4 preds

#define Y_OFF_ENC (0)

#define U_OFF_ENC (16)

#define V_OFF_ENC (16 + 8)

extern const uint16_t VP8Scan[16];

extern const uint16_t VP8UVModeOffsets[4];

extern const uint16_t VP8I16ModeOffsets[4];

// Layout of prediction blocks

// intra 16x16

#define I16DC16 (0 * 16 * BPS)

#define I16TM16 (I16DC16 + 16)

#define I16VE16 (1 * 16 * BPS)

#define I16HE16 (I16VE16 + 16)

// chroma 8x8, two U/V blocks side by side (hence: 16x8 each)

#define C8DC8 (2 * 16 * BPS)

#define C8TM8 (C8DC8 + 1 * 16)

#define C8VE8 (2 * 16 * BPS + 8 * BPS)

#define C8HE8 (C8VE8 + 1 * 16)

// intra 4x4

#define I4DC4 (3 * 16 * BPS + 0)

#define I4TM4 (I4DC4 + 4)

#define I4VE4 (I4DC4 + 8)

#define I4HE4 (I4DC4 + 12)

#define I4RD4 (I4DC4 + 16)

#define I4VR4 (I4DC4 + 20)

#define I4LD4 (I4DC4 + 24)

#define I4VL4 (I4DC4 + 28)

#define I4HD4 (3 * 16 * BPS + 4 * BPS)

#define I4HU4 (I4HD4 + 4)

#define I4TMP (I4HD4 + 8)

typedef int64_t score_t;  // type used for scores, rate, distortion

// Note that MAX_COST is not the maximum allowed by sizeof(score_t),

// in order to allow overflowing computations.

#define MAX_COST ((score_t)0x7fffffffffffffLL)

#define QFIX 17

#define BIAS(b) ((b) << (QFIX - 8))

// Fun fact: this is the _only_ line where we're actually being lossy and

// discarding bits.

static WEBP_INLINE int QUANTDIV(uint32_t n, uint32_t iQ, uint32_t B) {

  return (int)((n * iQ + B) >> QFIX);

}

Unexecuted instantiation: picture_csp_enc.c:QUANTDIV

Unexecuted instantiation: picture_enc.c:QUANTDIV

Unexecuted instantiation: webp_enc.c:QUANTDIV

Unexecuted instantiation: cost.c:QUANTDIV

Unexecuted instantiation: enc.c:QUANTDIV

Unexecuted instantiation: cost_sse2.c:QUANTDIV

Unexecuted instantiation: enc_sse2.c:QUANTDIV

Unexecuted instantiation: enc_sse41.c:QUANTDIV

Unexecuted instantiation: alpha_enc.c:QUANTDIV

Unexecuted instantiation: analysis_enc.c:QUANTDIV

Unexecuted instantiation: frame_enc.c:QUANTDIV

Unexecuted instantiation: iterator_enc.c:QUANTDIV

Unexecuted instantiation: picture_tools_enc.c:QUANTDIV

quant_enc.c:QUANTDIV

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static WEBP_INLINE int QUANTDIV(uint32_t n, uint32_t iQ, uint32_t B) {

120

57.3M

  return (int)((n * iQ + B) >> QFIX);

121

57.3M

}

Unexecuted instantiation: syntax_enc.c:QUANTDIV

Unexecuted instantiation: token_enc.c:QUANTDIV

Unexecuted instantiation: tree_enc.c:QUANTDIV

Unexecuted instantiation: vp8l_enc.c:QUANTDIV

Unexecuted instantiation: backward_references_enc.c:QUANTDIV

Unexecuted instantiation: cost_enc.c:QUANTDIV

Unexecuted instantiation: filter_enc.c:QUANTDIV

Unexecuted instantiation: histogram_enc.c:QUANTDIV

Unexecuted instantiation: picture_rescale_enc.c:QUANTDIV

Unexecuted instantiation: predictor_enc.c:QUANTDIV

// Uncomment the following to remove token-buffer code:

// #define DISABLE_TOKEN_BUFFER

// quality below which error-diffusion is enabled

#define ERROR_DIFFUSION_QUALITY 98

//------------------------------------------------------------------------------

// Headers

typedef uint32_t proba_t;  // 16b + 16b

typedef uint8_t ProbaArray[NUM_CTX][NUM_PROBAS];

typedef proba_t StatsArray[NUM_CTX][NUM_PROBAS];

typedef uint16_t CostArray[NUM_CTX][MAX_VARIABLE_LEVEL + 1];

typedef const uint16_t* (*CostArrayPtr)[NUM_CTX];  // for easy casting

typedef const uint16_t* CostArrayMap[16][NUM_CTX];

typedef double LFStats[NUM_MB_SEGMENTS][MAX_LF_LEVELS];  // filter stats

typedef struct VP8Encoder VP8Encoder;

// segment features

typedef struct {

  int num_segments;  // Actual number of segments. 1 segment only = unused.

  int update_map;    // whether to update the segment map or not.

                     // must be 0 if there's only 1 segment.

  int size;          // bit-cost for transmitting the segment map

} VP8EncSegmentHeader;

// Struct collecting all frame-persistent probabilities.

typedef struct {

  uint8_t segments[3];  // probabilities for segment tree

  uint8_t skip_proba;   // final probability of being skipped.

  ProbaArray coeffs[NUM_TYPES][NUM_BANDS];     // 1056 bytes

  StatsArray stats[NUM_TYPES][NUM_BANDS];      // 4224 bytes

  CostArray level_cost[NUM_TYPES][NUM_BANDS];  // 13056 bytes

  CostArrayMap remapped_costs[NUM_TYPES];      // 1536 bytes

  int dirty;           // if true, need to call VP8CalculateLevelCosts()

  int use_skip_proba;  // Note: we always use skip_proba for now.

  int nb_skip;         // number of skipped blocks

} VP8EncProba;

// Filter parameters. Not actually used in the code (we don't perform

// the in-loop filtering), but filled from user's config

typedef struct {

  int simple;         // filtering type: 0=complex, 1=simple

  int level;          // base filter level [0..63]

  int sharpness;      // [0..7]

  int i4x4_lf_delta;  // delta filter level for i4x4 relative to i16x16

} VP8EncFilterHeader;

//------------------------------------------------------------------------------

// Informations about the macroblocks.

typedef struct {

  // block type

  unsigned int type : 2;  // 0=i4x4, 1=i16x16

  unsigned int uv_mode : 2;

  unsigned int skip : 1;

  unsigned int segment : 2;

  uint8_t alpha;  // quantization-susceptibility

} VP8MBInfo;

typedef struct VP8Matrix {

  uint16_t q[16];        // quantizer steps

  uint16_t iq[16];       // reciprocals, fixed point.

  uint32_t bias[16];     // rounding bias

  uint32_t zthresh[16];  // value below which a coefficient is zeroed

  uint16_t sharpen[16];  // frequency boosters for slight sharpening

} VP8Matrix;

typedef struct {

  VP8Matrix y1, y2, uv;  // quantization matrices

  int alpha;      // quant-susceptibility, range [-127,127]. Zero is neutral.

                  // Lower values indicate a lower risk of blurriness.

  int beta;       // filter-susceptibility, range [0,255].

  int quant;      // final segment quantizer.

  int fstrength;  // final in-loop filtering strength

  int max_edge;   // max edge delta (for filtering strength)

  int min_disto;  // minimum distortion required to trigger filtering record

  // reactivities

  int lambda_i16, lambda_i4, lambda_uv;

  int lambda_mode, lambda_trellis, tlambda;

  int lambda_trellis_i16, lambda_trellis_i4, lambda_trellis_uv;

  // lambda values for distortion-based evaluation

  score_t i4_penalty;  // penalty for using Intra4

} VP8SegmentInfo;

typedef int8_t DError[2 /* u/v */][2 /* top or left */];

// Handy transient struct to accumulate score and info during RD-optimization

// and mode evaluation.

typedef struct {

  score_t D, SD;            // Distortion, spectral distortion

  score_t H, R, score;      // header bits, rate, score.

  int16_t y_dc_levels[16];  // Quantized levels for luma-DC, luma-AC, chroma.

  int16_t y_ac_levels[16][16];

  int16_t uv_levels[4 + 4][16];

  int mode_i16;          // mode number for intra16 prediction

  uint8_t modes_i4[16];  // mode numbers for intra4 predictions

  int mode_uv;           // mode number of chroma prediction

  uint32_t nz;           // non-zero blocks

  int8_t derr[2][3];     // DC diffusion errors for U/V for blocks #1/2/3

} VP8ModeScore;

// Iterator structure to iterate through macroblocks, pointing to the

// right neighbouring data (samples, predictions, contexts, ...)

typedef struct {

  int x, y;           // current macroblock

  uint8_t* yuv_in;    // input samples

  uint8_t* yuv_out;   // output samples

  uint8_t* yuv_out2;  // secondary buffer swapped with yuv_out.

  uint8_t* yuv_p;     // scratch buffer for prediction

  VP8Encoder* enc;    // back-pointer

  VP8MBInfo* mb;      // current macroblock

  VP8BitWriter* bw;   // current bit-writer

  uint8_t* preds;     // intra mode predictors (4x4 blocks)

  uint32_t* nz;       // non-zero pattern

#if WEBP_AARCH64 && BPS == 32

  uint8_t i4_boundary[40];  // 32+8 boundary samples needed by intra4x4

#else

  uint8_t i4_boundary[37];  // 32+5 boundary samples needed by intra4x4

#endif

  uint8_t* i4_top;           // pointer to the current top boundary sample

  int i4;                    // current intra4x4 mode being tested

  int top_nz[9];             // top-non-zero context.

  int left_nz[9];            // left-non-zero. left_nz[8] is independent.

  uint64_t bit_count[4][3];  // bit counters for coded levels.

  uint64_t luma_bits;        // macroblock bit-cost for luma

  uint64_t uv_bits;          // macroblock bit-cost for chroma

  LFStats* lf_stats;         // filter stats (borrowed from enc)

  int do_trellis;            // if true, perform extra level optimisation

  int count_down;            // number of mb still to be processed

  int count_down0;           // starting counter value (for progress)

  int percent0;              // saved initial progress percent

  DError left_derr;  // left error diffusion (u/v)

  DError* top_derr;  // top diffusion error - NULL if disabled

  uint8_t* y_left;  // left luma samples (addressable from index -1 to 15).

  uint8_t* u_left;  // left u samples (addressable from index -1 to 7)

  uint8_t* v_left;  // left v samples (addressable from index -1 to 7)

  uint8_t* y_top;   // top luma samples at position 'x'

  uint8_t* uv_top;  // top u/v samples at position 'x', packed as 16 bytes

  // memory for storing y/u/v_left

  uint8_t yuv_left_mem[17 + 16 + 16 + 8 + WEBP_ALIGN_CST];

  // memory for yuv*

  uint8_t yuv_mem[3 * YUV_SIZE_ENC + PRED_SIZE_ENC + WEBP_ALIGN_CST];

} VP8EncIterator;

// in iterator.c

// must be called first

void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it);

// reset iterator position to row 'y'

void VP8IteratorSetRow(VP8EncIterator* const it, int y);

// set count down (=number of iterations to go)

void VP8IteratorSetCountDown(VP8EncIterator* const it, int count_down);

// return true if iteration is finished

int VP8IteratorIsDone(const VP8EncIterator* const it);

// Import uncompressed samples from source.

// If tmp_32 is not NULL, import boundary samples too.

// tmp_32 is a 32-bytes scratch buffer that must be aligned in memory.

void VP8IteratorImport(VP8EncIterator* const it, uint8_t* const tmp_32);

// export decimated samples

void VP8IteratorExport(const VP8EncIterator* const it);

// go to next macroblock. Returns false if not finished.

int VP8IteratorNext(VP8EncIterator* const it);

// save the 'yuv_out' boundary values to 'top'/'left' arrays for next

// iterations.

void VP8IteratorSaveBoundary(VP8EncIterator* const it);

// Report progression based on macroblock rows. Return 0 for user-abort request.

int VP8IteratorProgress(const VP8EncIterator* const it, int delta);

// Intra4x4 iterations

void VP8IteratorStartI4(VP8EncIterator* const it);

// returns true if not done.

int VP8IteratorRotateI4(VP8EncIterator* const it, const uint8_t* const yuv_out);

// Non-zero context setup/teardown

void VP8IteratorNzToBytes(VP8EncIterator* const it);

void VP8IteratorBytesToNz(VP8EncIterator* const it);

// Helper functions to set mode properties

void VP8SetIntra16Mode(const VP8EncIterator* const it, int mode);

void VP8SetIntra4Mode(const VP8EncIterator* const it, const uint8_t* modes);

void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode);

void VP8SetSkip(const VP8EncIterator* const it, int skip);

void VP8SetSegment(const VP8EncIterator* const it, int segment);

//------------------------------------------------------------------------------

// Paginated token buffer

typedef struct VP8Tokens VP8Tokens;  // struct details in token.c

typedef struct {

#if !defined(DISABLE_TOKEN_BUFFER)

  VP8Tokens* pages;       // first page

  VP8Tokens** last_page;  // last page

  uint16_t* tokens;       // set to (*last_page)->tokens

  int left;               // how many free tokens left before the page is full

  int page_size;          // number of tokens per page

#endif

  int error;  // true in case of malloc error

} VP8TBuffer;

// initialize an empty buffer

void VP8TBufferInit(VP8TBuffer* const b, int page_size);

void VP8TBufferClear(VP8TBuffer* const b);  // de-allocate pages memory

#if !defined(DISABLE_TOKEN_BUFFER)

// Finalizes bitstream when probabilities are known.

// Deletes the allocated token memory if final_pass is true.

int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,

                  const uint8_t* const probas, int final_pass);

// record the coding of coefficients without knowing the probabilities yet

int VP8RecordCoeffTokens(int ctx, const struct VP8Residual* const res,

                         VP8TBuffer* const tokens);

// Estimate the final coded size given a set of 'probas'.

size_t VP8EstimateTokenSize(VP8TBuffer* const b, const uint8_t* const probas);

#endif  // !DISABLE_TOKEN_BUFFER

//------------------------------------------------------------------------------

// VP8Encoder

struct VP8Encoder {

  const WebPConfig* config;  // user configuration and parameters

  WebPPicture* pic;          // input / output picture

  // headers

  VP8EncFilterHeader filter_hdr;    // filtering information

  VP8EncSegmentHeader segment_hdr;  // segment information

  int profile;  // VP8's profile, deduced from Config.

  // dimension, in macroblock units.

  int mb_w, mb_h;

  int preds_w;  // stride of the *preds prediction plane (=4*mb_w + 1)

  // number of partitions (1, 2, 4 or 8 = MAX_NUM_PARTITIONS)

  int num_parts;

  // per-partition boolean decoders.

  VP8BitWriter bw;                         // part0

  VP8BitWriter parts[MAX_NUM_PARTITIONS];  // token partitions

  VP8TBuffer tokens;                       // token buffer

  int percent;  // for progress

  // transparency blob

  int has_alpha;

  uint8_t* alpha_data;  // non-NULL if transparency is present

  uint32_t alpha_data_size;

  WebPWorker alpha_worker;

  // quantization info (one set of DC/AC dequant factor per segment)

  VP8SegmentInfo dqm[NUM_MB_SEGMENTS];

  int base_quant;  // nominal quantizer value. Only used

                   // for relative coding of segments' quant.

  int alpha;       // global susceptibility (<=> complexity)

  int uv_alpha;    // U/V quantization susceptibility

  // global offset of quantizers, shared by all segments

  int dq_y1_dc;

  int dq_y2_dc, dq_y2_ac;

  int dq_uv_dc, dq_uv_ac;

  // probabilities and statistics

  VP8EncProba proba;

  uint64_t sse[4];     // sum of Y/U/V/A squared errors for all macroblocks

  uint64_t sse_count;  // pixel count for the sse[] stats

  int coded_size;

  int residual_bytes[3][4];

  int block_count[3];

  // quality/speed settings

  int method;               // 0=fastest, 6=best/slowest.

  VP8RDLevel rd_opt_level;  // Deduced from method.

  int max_i4_header_bits;   // partition #0 safeness factor

  int mb_header_limit;      // rough limit for header bits per MB

  int thread_level;         // derived from config->thread_level

  int do_search;            // derived from config->target_XXX

  int use_tokens;           // if true, use token buffer

  // Memory

  VP8MBInfo* mb_info;  // contextual macroblock infos (mb_w + 1)

  uint8_t* preds;      // predictions modes: (4*mb_w+1) * (4*mb_h+1)

  uint32_t* nz;        // non-zero bit context: mb_w+1

  uint8_t* y_top;      // top luma samples.

  uint8_t* uv_top;     // top u/v samples.

                       // U and V are packed into 16 bytes (8 U + 8 V)

  LFStats* lf_stats;   // autofilter stats (if NULL, autofilter is off)

  DError* top_derr;    // diffusion error (NULL if disabled)

};

//------------------------------------------------------------------------------

// internal functions. Not public.

// in tree.c

extern const uint8_t VP8CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];

extern const uint8_t VP8CoeffsUpdateProba[NUM_TYPES][NUM_BANDS][NUM_CTX]

                                         [NUM_PROBAS];

// Reset the token probabilities to their initial (default) values

void VP8DefaultProbas(VP8Encoder* const enc);

// Write the token probabilities

void VP8WriteProbas(VP8BitWriter* const bw, const VP8EncProba* const probas);

// Writes the partition #0 modes (that is: all intra modes)

void VP8CodeIntraModes(VP8Encoder* const enc);

// in syntax.c

// Generates the final bitstream by coding the partition0 and headers,

// and appending an assembly of all the pre-coded token partitions.

// Return true if everything is ok.

int VP8EncWrite(VP8Encoder* const enc);

// Release memory allocated for bit-writing in VP8EncLoop & seq.

void VP8EncFreeBitWriters(VP8Encoder* const enc);

// in frame.c

extern const uint8_t VP8Cat3[];

extern const uint8_t VP8Cat4[];

extern const uint8_t VP8Cat5[];

extern const uint8_t VP8Cat6[];

// Form all the four Intra16x16 predictions in the 'yuv_p' cache

void VP8MakeLuma16Preds(const VP8EncIterator* const it);

// Form all the four Chroma8x8 predictions in the 'yuv_p' cache

void VP8MakeChroma8Preds(const VP8EncIterator* const it);

// Rate calculation

int VP8GetCostLuma16(VP8EncIterator* const it, const VP8ModeScore* const rd);

int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]);

int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd);

// Main coding calls

int VP8EncLoop(VP8Encoder* const enc);

int VP8EncTokenLoop(VP8Encoder* const enc);

// in webpenc.c

// Assign an error code to a picture. Return false for convenience.

int WebPEncodingSetError(const WebPPicture* const pic, WebPEncodingError error);

int WebPReportProgress(const WebPPicture* const pic, int percent,

                       int* const percent_store);

// in analysis.c

// Main analysis loop. Decides the segmentations and complexity.

// Assigns a first guess for Intra16 and 'uvmode' prediction modes.

int VP8EncAnalyze(VP8Encoder* const enc);

// in quant.c

// Sets up segment's quantization values, 'base_quant' and filter strengths.

void VP8SetSegmentParams(VP8Encoder* const enc, float quality);

// Pick best modes and fills the levels. Returns true if skipped.

int VP8Decimate(VP8EncIterator* WEBP_RESTRICT const it,

                VP8ModeScore* WEBP_RESTRICT const rd, VP8RDLevel rd_opt);

// in alpha.c

void VP8EncInitAlpha(VP8Encoder* const enc);   // initialize alpha compression

int VP8EncStartAlpha(VP8Encoder* const enc);   // start alpha coding process

int VP8EncFinishAlpha(VP8Encoder* const enc);  // finalize compressed data

int VP8EncDeleteAlpha(VP8Encoder* const enc);  // delete compressed data

// autofilter

void VP8InitFilter(VP8EncIterator* const it);

void VP8StoreFilterStats(VP8EncIterator* const it);

void VP8AdjustFilterStrength(VP8EncIterator* const it);

// returns the approximate filtering strength needed to smooth a edge

// step of 'delta', given a sharpness parameter 'sharpness'.

int VP8FilterStrengthFromDelta(int sharpness, int delta);

// misc utils for picture_*.c:

// Returns true if 'picture' is non-NULL and dimensions/colorspace are within

// their valid ranges. If returning false, the 'error_code' in 'picture' is

// updated.

int WebPValidatePicture(const WebPPicture* const picture);

// Remove reference to the ARGB/YUVA buffer (doesn't free anything).

void WebPPictureResetBuffers(WebPPicture* const picture);

// Allocates ARGB buffer according to set width/height (previous one is

// always free'd). Preserves the YUV(A) buffer. Returns false in case of error

// (invalid param, out-of-memory).

int WebPPictureAllocARGB(WebPPicture* const picture);

// Allocates YUVA buffer according to set width/height (previous one is always

// free'd). Uses picture->csp to determine whether an alpha buffer is needed.

// Preserves the ARGB buffer.

// Returns false in case of error (invalid param, out-of-memory).

int WebPPictureAllocYUVA(WebPPicture* const picture);

// Replace samples that are fully transparent by 'color' to help compressibility

// (no guarantee, though). Assumes pic->use_argb is true.

void WebPReplaceTransparentPixels(WebPPicture* const pic, uint32_t color);

//------------------------------------------------------------------------------

#ifdef __cplusplus

}  // extern "C"

#endif

#endif  // WEBP_ENC_VP8I_ENC_H_