text: // 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_VP8ENCI_H_
  #define WEBP_ENC_VP8ENCI_H_
  
  #include <string.h>     // for memcpy()
  #include "../webp/encode.h"
  #include "../dsp/dsp.h"
  #include "../utils/bit_writer.h"
  #include "../utils/thread.h"
  
  #if defined(__cplusplus) || defined(c_plusplus)
  extern "C" {
  #endif
  
  //------------------------------------------------------------------------------
  // Various defines and enums
  
  // version numbers
  #define ENC_MAJ_VERSION 0
  #define ENC_MIN_VERSION 3
  #define ENC_REV_VERSION 0
  
  // intra prediction modes
  enum { B_DC_PRED = 0,   // 4x4 modes
         B_TM_PRED = 1,
         B_VE_PRED = 2,
         B_HE_PRED = 3,
         B_RD_PRED = 4,
         B_VR_PRED = 5,
         B_LD_PRED = 6,
         B_VL_PRED = 7,
         B_HD_PRED = 8,
         B_HU_PRED = 9,
         NUM_BMODES = B_HU_PRED + 1 - B_DC_PRED,  // = 10
  
         // Luma16 or UV modes
         DC_PRED = B_DC_PRED, V_PRED = B_VE_PRED,
         H_PRED = B_HE_PRED, TM_PRED = B_TM_PRED,
         NUM_PRED_MODES = 4
       };
  
  enum { NUM_MB_SEGMENTS = 4,
         MAX_NUM_PARTITIONS = 8,
         NUM_TYPES = 4,   // 0: i16-AC,  1: i16-DC,  2:chroma-AC,  3:i4-AC
         NUM_BANDS = 8,
         NUM_CTX = 3,
         NUM_PROBAS = 11,
         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 16-pixels wide.
  // 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. See VP8Scan[] for accessing the blocks.
  //  Y_OFF  |YYYY| <- original samples  (enc->yuv_in_)
  //         |YYYY|
  //         |YYYY|
  //         |YYYY|
  //  U_OFF  |UUVV| V_OFF  (=U_OFF + 8)
  //         |UUVV|
  //         +----+
  //  Y_OFF  |YYYY| <- compressed/decoded samples  ('yuv_out_')
  //         |YYYY|    There are two buffers like this ('yuv_out_'/'yuv_out2_')
  //         |YYYY|
  //         |YYYY|
  //  U_OFF  |UUVV| V_OFF
  //         |UUVV|
  //          x2 (for yuv_out2_)
  //         +----+     Prediction area ('yuv_p_', size = PRED_SIZE)
  // I16DC16 |YYYY|  Intra16 predictions (16x16 block each)
  //         |YYYY|
  //         |YYYY|
  //         |YYYY|
  // I16TM16 |YYYY|
  //         |YYYY|
  //         |YYYY|
  //         |YYYY|
  // I16VE16 |YYYY|
  //         |YYYY|
  //         |YYYY|
  //         |YYYY|
  // I16HE16 |YYYY|
  //         |YYYY|
  //         |YYYY|
  //         |YYYY|
  //         +----+  Chroma U/V predictions (16x8 block each)
  // C8DC8   |UUVV|
  //         |UUVV|
  // C8TM8   |UUVV|
  //         |UUVV|
  // C8VE8   |UUVV|
  //         |UUVV|
  // C8HE8   |UUVV|
  //         |UUVV|
  //         +----+  Intra 4x4 predictions (4x4 block each)
  //         |YYYY| I4DC4 I4TM4 I4VE4 I4HE4
  //         |YYYY| I4RD4 I4VR4 I4LD4 I4VL4
  //         |YY..| I4HD4 I4HU4 I4TMP
  //         +----+
  #define BPS       16   // this is the common stride
  #define Y_SIZE   (BPS * 16)
  #define UV_SIZE  (BPS * 8)
  #define YUV_SIZE (Y_SIZE + UV_SIZE)
  #define PRED_SIZE (6 * 16 * BPS + 12 * BPS)
  #define Y_OFF    (0)
  #define U_OFF    (Y_SIZE)
  #define V_OFF    (U_OFF + 8)
  #define ALIGN_CST 15
  #define DO_ALIGN(PTR) ((uintptr_t)((PTR) + ALIGN_CST) & ~ALIGN_CST)
  
  extern const int VP8Scan[16 + 4 + 4];           // in quant.c
  extern const int VP8UVModeOffsets[4];           // in analyze.c
  extern const int VP8I16ModeOffsets[4];
  extern const int VP8I4ModeOffsets[NUM_BMODES];
  
  // Layout of prediction blocks
  // intra 16x16
  #define I16DC16 (0 * 16 * BPS)
  #define I16TM16 (1 * 16 * BPS)
  #define I16VE16 (2 * 16 * BPS)
  #define I16HE16 (3 * 16 * BPS)
  // chroma 8x8, two U/V blocks side by side (hence: 16x8 each)
  #define C8DC8 (4 * 16 * BPS)
  #define C8TM8 (4 * 16 * BPS + 8 * BPS)
  #define C8VE8 (5 * 16 * BPS)
  #define C8HE8 (5 * 16 * BPS + 8 * BPS)
  // intra 4x4
  #define I4DC4 (6 * 16 * BPS +  0)
  #define I4TM4 (6 * 16 * BPS +  4)
  #define I4VE4 (6 * 16 * BPS +  8)
  #define I4HE4 (6 * 16 * BPS + 12)
  #define I4RD4 (6 * 16 * BPS + 4 * BPS +  0)
  #define I4VR4 (6 * 16 * BPS + 4 * BPS +  4)
  #define I4LD4 (6 * 16 * BPS + 4 * BPS +  8)
  #define I4VL4 (6 * 16 * BPS + 4 * BPS + 12)
  #define I4HD4 (6 * 16 * BPS + 8 * BPS +  0)
  #define I4HU4 (6 * 16 * BPS + 8 * BPS +  4)
  #define I4TMP (6 * 16 * BPS + 8 * BPS +  8)
  
  typedef int64_t score_t;     // type used for scores, rate, distortion
  #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(int n, int iQ, int B) {
    return (n * iQ + B) >> QFIX;
  }
  
  // size of histogram used by CollectHistogram.
  #define MAX_COEFF_THRESH   31
  typedef struct VP8Histogram VP8Histogram;
  struct VP8Histogram {
    // TODO(skal): we only need to store the max_value and last_non_zero actually.
    int distribution[MAX_COEFF_THRESH + 1];
  };
  
  // Uncomment the following to remove token-buffer code:
  // #define DISABLE_TOKEN_BUFFER
  
  //------------------------------------------------------------------------------
  // 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 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
  } VP8SegmentHeader;
  
  // 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];      // 924 bytes
    StatsArray stats_[NUM_TYPES][NUM_BANDS];       // 4224 bytes
    CostArray level_cost_[NUM_TYPES][NUM_BANDS];   // 11.4k
    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
  } VP8Proba;
  
  // 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
  } VP8FilterHeader;
  
  //------------------------------------------------------------------------------
  // 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.
    uint16_t bias_[16];     // rounding bias
    uint16_t zthresh_[16];  // value under 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
    // reactivities
    int lambda_i16_, lambda_i4_, lambda_uv_;
    int lambda_mode_, lambda_trellis_, tlambda_;
    int lambda_trellis_i16_, lambda_trellis_i4_, lambda_trellis_uv_;
  } VP8SegmentInfo;
  
  // Handy transcient struct to accumulate score and info during RD-optimization
  // and mode evaluation.
  typedef struct {
    score_t D, SD, R, score;    // Distortion, spectral distortion, 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
  } VP8ModeScore;
  
  // Iterator structure to iterate through macroblocks, pointing to the
  // right neighbouring data (samples, predictions, contexts, ...)
  typedef struct {
    int x_, y_;                      // current macroblock
    int y_offset_, uv_offset_;       // offset to the luma / chroma planes
    int y_stride_, uv_stride_;       // respective strides
    uint8_t*      yuv_in_;           // borrowed from enc_ (for now)
    uint8_t*      yuv_out_;          // ''
    uint8_t*      yuv_out2_;         // ''
    uint8_t*      yuv_p_;            // ''
    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
    uint8_t       i4_boundary_[37];  // 32+5 boundary samples needed by intra4x4
    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           done_;             // true when scan is finished
    int           percent0_;         // saved initial progress percent
  } VP8EncIterator;
  
    // in iterator.c
  // must be called first.
  void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it);
  // restart a scan.
  void VP8IteratorReset(VP8EncIterator* const it);
  // import samples from source
  void VP8IteratorImport(const VP8EncIterator* const it);
  // export decimated samples
  void VP8IteratorExport(const VP8EncIterator* const it);
  // go to next macroblock. Returns !done_. If *block_to_save is non-null, will
  // save the boundary values to top_/left_ arrays. block_to_save can be
  // it->yuv_out_ or it->yuv_in_.
  int VP8IteratorNext(VP8EncIterator* const it,
                      const uint8_t* const block_to_save);
  // Report progression based on macroblock rows. Return 0 for user-abort request.
  int VP8IteratorProgress(const VP8EncIterator* const it,
                          int final_delta_percent);
  // 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.
  #endif
    int error_;         // true in case of malloc error
  } VP8TBuffer;
  
  void VP8TBufferInit(VP8TBuffer* const b);    // initialize an empty buffer
  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, int coeff_type, int first, int last,
                           const int16_t* const coeffs,
                           VP8TBuffer* const tokens);
  
  // unused for now
  void VP8TokenToStats(const VP8TBuffer* const b, proba_t* const stats);
  
  #endif  // !DISABLE_TOKEN_BUFFER
  
  //------------------------------------------------------------------------------
  // VP8Encoder
  
  struct VP8Encoder {
    const WebPConfig* config_;    // user configuration and parameters
    WebPPicture* pic_;            // input / output picture
  
    // headers
    VP8FilterHeader   filter_hdr_;     // filtering information
    VP8SegmentHeader  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_;
  
    // enhancement layer
    int use_layer_;
    VP8BitWriter layer_bw_;
    uint8_t* layer_data_;
    size_t layer_data_size_;
  
    // 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
    VP8Proba 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 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*   yuv_in_;    // input samples
    uint8_t*   yuv_out_;   // output samples
    uint8_t*   yuv_out2_;  // secondary scratch out-buffer. swapped with yuv_out_.
    uint8_t*   yuv_p_;     // scratch buffer for prediction
    uint8_t   *y_top_;     // top luma samples.
    uint8_t   *uv_top_;    // top u/v samples.
                           // U and V are packed into 16 pixels (8 U + 8 V)
    uint8_t   *y_left_;    // left luma samples (adressable from index -1 to 15).
    uint8_t   *u_left_;    // left u samples (adressable from index -1 to 7)
    uint8_t   *v_left_;    // left v samples (adressable from index -1 to 7)
  
    LFStats   *lf_stats_;  // autofilter stats (if NULL, autofilter is off)
  };
  
  //------------------------------------------------------------------------------
  // 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 VP8Proba* 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 VP8EncBands[16 + 1];
  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);
  // Form all the ten Intra4x4 predictions in the yuv_p_ cache
  // for the 4x4 block it->i4_
  void VP8MakeIntra4Preds(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* const it, VP8ModeScore* 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
  
    // in layer.c
  void VP8EncInitLayer(VP8Encoder* const enc);     // init everything
  void VP8EncCodeLayerBlock(VP8EncIterator* it);   // code one more macroblock
  int VP8EncFinishLayer(VP8Encoder* const enc);    // finalize coding
  void VP8EncDeleteLayer(VP8Encoder* enc);         // reclaim memory
  
    // in filter.c
  
  // SSIM utils
  typedef struct {
    double w, xm, ym, xxm, xym, yym;
  } DistoStats;
  void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst);
  void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
                              const uint8_t* src2, int stride2,
                              int W, int H, DistoStats* const stats);
  double VP8SSIMGet(const DistoStats* const stats);
  double VP8SSIMGetSquaredError(const DistoStats* const stats);
  
  // autofilter
  void VP8InitFilter(VP8EncIterator* const it);
  void VP8StoreFilterStats(VP8EncIterator* const it);
  void VP8AdjustFilterStrength(VP8EncIterator* const it);
  
  //------------------------------------------------------------------------------
  
  #if defined(__cplusplus) || defined(c_plusplus)
  }    // extern "C"
  #endif
  
  #endif  /* WEBP_ENC_VP8ENCI_H_ */
  