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      1 // Copyright 2011 Google Inc. All Rights Reserved.
      2 //
      3 // Use of this source code is governed by a BSD-style license
      4 // that can be found in the COPYING file in the root of the source
      5 // tree. An additional intellectual property rights grant can be found
      6 // in the file PATENTS. All contributing project authors may
      7 // be found in the AUTHORS file in the root of the source tree.
      8 // -----------------------------------------------------------------------------
      9 //
     10 //   WebP encoder: internal header.
     11 //
     12 // Author: Skal (pascal.massimino (at) gmail.com)
     13 
     14 #ifndef WEBP_ENC_VP8ENCI_H_
     15 #define WEBP_ENC_VP8ENCI_H_
     16 
     17 #include <string.h>     // for memcpy()
     18 #include "../webp/encode.h"
     19 #include "../dsp/dsp.h"
     20 #include "../utils/bit_writer.h"
     21 #include "../utils/thread.h"
     22 
     23 #if defined(__cplusplus) || defined(c_plusplus)
     24 extern "C" {
     25 #endif
     26 
     27 //------------------------------------------------------------------------------
     28 // Various defines and enums
     29 
     30 // version numbers
     31 #define ENC_MAJ_VERSION 0
     32 #define ENC_MIN_VERSION 3
     33 #define ENC_REV_VERSION 1
     34 
     35 // intra prediction modes
     36 enum { B_DC_PRED = 0,   // 4x4 modes
     37        B_TM_PRED = 1,
     38        B_VE_PRED = 2,
     39        B_HE_PRED = 3,
     40        B_RD_PRED = 4,
     41        B_VR_PRED = 5,
     42        B_LD_PRED = 6,
     43        B_VL_PRED = 7,
     44        B_HD_PRED = 8,
     45        B_HU_PRED = 9,
     46        NUM_BMODES = B_HU_PRED + 1 - B_DC_PRED,  // = 10
     47 
     48        // Luma16 or UV modes
     49        DC_PRED = B_DC_PRED, V_PRED = B_VE_PRED,
     50        H_PRED = B_HE_PRED, TM_PRED = B_TM_PRED,
     51        NUM_PRED_MODES = 4
     52      };
     53 
     54 enum { NUM_MB_SEGMENTS = 4,
     55        MAX_NUM_PARTITIONS = 8,
     56        NUM_TYPES = 4,   // 0: i16-AC,  1: i16-DC,  2:chroma-AC,  3:i4-AC
     57        NUM_BANDS = 8,
     58        NUM_CTX = 3,
     59        NUM_PROBAS = 11,
     60        MAX_LF_LEVELS = 64,       // Maximum loop filter level
     61        MAX_VARIABLE_LEVEL = 67,  // last (inclusive) level with variable cost
     62        MAX_LEVEL = 2047          // max level (note: max codable is 2047 + 67)
     63      };
     64 
     65 typedef enum {   // Rate-distortion optimization levels
     66   RD_OPT_NONE        = 0,  // no rd-opt
     67   RD_OPT_BASIC       = 1,  // basic scoring (no trellis)
     68   RD_OPT_TRELLIS     = 2,  // perform trellis-quant on the final decision only
     69   RD_OPT_TRELLIS_ALL = 3   // trellis-quant for every scoring (much slower)
     70 } VP8RDLevel;
     71 
     72 // YUV-cache parameters. Cache is 16-pixels wide.
     73 // The original or reconstructed samples can be accessed using VP8Scan[]
     74 // The predicted blocks can be accessed using offsets to yuv_p_ and
     75 // the arrays VP8*ModeOffsets[];
     76 //         +----+      YUV Samples area. See VP8Scan[] for accessing the blocks.
     77 //  Y_OFF  |YYYY| <- original samples  (enc->yuv_in_)
     78 //         |YYYY|
     79 //         |YYYY|
     80 //         |YYYY|
     81 //  U_OFF  |UUVV| V_OFF  (=U_OFF + 8)
     82 //         |UUVV|
     83 //         +----+
     84 //  Y_OFF  |YYYY| <- compressed/decoded samples  ('yuv_out_')
     85 //         |YYYY|    There are two buffers like this ('yuv_out_'/'yuv_out2_')
     86 //         |YYYY|
     87 //         |YYYY|
     88 //  U_OFF  |UUVV| V_OFF
     89 //         |UUVV|
     90 //          x2 (for yuv_out2_)
     91 //         +----+     Prediction area ('yuv_p_', size = PRED_SIZE)
     92 // I16DC16 |YYYY|  Intra16 predictions (16x16 block each)
     93 //         |YYYY|
     94 //         |YYYY|
     95 //         |YYYY|
     96 // I16TM16 |YYYY|
     97 //         |YYYY|
     98 //         |YYYY|
     99 //         |YYYY|
    100 // I16VE16 |YYYY|
    101 //         |YYYY|
    102 //         |YYYY|
    103 //         |YYYY|
    104 // I16HE16 |YYYY|
    105 //         |YYYY|
    106 //         |YYYY|
    107 //         |YYYY|
    108 //         +----+  Chroma U/V predictions (16x8 block each)
    109 // C8DC8   |UUVV|
    110 //         |UUVV|
    111 // C8TM8   |UUVV|
    112 //         |UUVV|
    113 // C8VE8   |UUVV|
    114 //         |UUVV|
    115 // C8HE8   |UUVV|
    116 //         |UUVV|
    117 //         +----+  Intra 4x4 predictions (4x4 block each)
    118 //         |YYYY| I4DC4 I4TM4 I4VE4 I4HE4
    119 //         |YYYY| I4RD4 I4VR4 I4LD4 I4VL4
    120 //         |YY..| I4HD4 I4HU4 I4TMP
    121 //         +----+
    122 #define BPS       16   // this is the common stride
    123 #define Y_SIZE   (BPS * 16)
    124 #define UV_SIZE  (BPS * 8)
    125 #define YUV_SIZE (Y_SIZE + UV_SIZE)
    126 #define PRED_SIZE (6 * 16 * BPS + 12 * BPS)
    127 #define Y_OFF    (0)
    128 #define U_OFF    (Y_SIZE)
    129 #define V_OFF    (U_OFF + 8)
    130 #define ALIGN_CST 15
    131 #define DO_ALIGN(PTR) ((uintptr_t)((PTR) + ALIGN_CST) & ~ALIGN_CST)
    132 
    133 extern const int VP8Scan[16 + 4 + 4];           // in quant.c
    134 extern const int VP8UVModeOffsets[4];           // in analyze.c
    135 extern const int VP8I16ModeOffsets[4];
    136 extern const int VP8I4ModeOffsets[NUM_BMODES];
    137 
    138 // Layout of prediction blocks
    139 // intra 16x16
    140 #define I16DC16 (0 * 16 * BPS)
    141 #define I16TM16 (1 * 16 * BPS)
    142 #define I16VE16 (2 * 16 * BPS)
    143 #define I16HE16 (3 * 16 * BPS)
    144 // chroma 8x8, two U/V blocks side by side (hence: 16x8 each)
    145 #define C8DC8 (4 * 16 * BPS)
    146 #define C8TM8 (4 * 16 * BPS + 8 * BPS)
    147 #define C8VE8 (5 * 16 * BPS)
    148 #define C8HE8 (5 * 16 * BPS + 8 * BPS)
    149 // intra 4x4
    150 #define I4DC4 (6 * 16 * BPS +  0)
    151 #define I4TM4 (6 * 16 * BPS +  4)
    152 #define I4VE4 (6 * 16 * BPS +  8)
    153 #define I4HE4 (6 * 16 * BPS + 12)
    154 #define I4RD4 (6 * 16 * BPS + 4 * BPS +  0)
    155 #define I4VR4 (6 * 16 * BPS + 4 * BPS +  4)
    156 #define I4LD4 (6 * 16 * BPS + 4 * BPS +  8)
    157 #define I4VL4 (6 * 16 * BPS + 4 * BPS + 12)
    158 #define I4HD4 (6 * 16 * BPS + 8 * BPS +  0)
    159 #define I4HU4 (6 * 16 * BPS + 8 * BPS +  4)
    160 #define I4TMP (6 * 16 * BPS + 8 * BPS +  8)
    161 
    162 typedef int64_t score_t;     // type used for scores, rate, distortion
    163 #define MAX_COST ((score_t)0x7fffffffffffffLL)
    164 
    165 #define QFIX 17
    166 #define BIAS(b)  ((b) << (QFIX - 8))
    167 // Fun fact: this is the _only_ line where we're actually being lossy and
    168 // discarding bits.
    169 static WEBP_INLINE int QUANTDIV(int n, int iQ, int B) {
    170   return (n * iQ + B) >> QFIX;
    171 }
    172 
    173 // size of histogram used by CollectHistogram.
    174 #define MAX_COEFF_THRESH   31
    175 typedef struct VP8Histogram VP8Histogram;
    176 struct VP8Histogram {
    177   // TODO(skal): we only need to store the max_value and last_non_zero actually.
    178   int distribution[MAX_COEFF_THRESH + 1];
    179 };
    180 
    181 // Uncomment the following to remove token-buffer code:
    182 // #define DISABLE_TOKEN_BUFFER
    183 
    184 //------------------------------------------------------------------------------
    185 // Headers
    186 
    187 typedef uint32_t proba_t;   // 16b + 16b
    188 typedef uint8_t ProbaArray[NUM_CTX][NUM_PROBAS];
    189 typedef proba_t StatsArray[NUM_CTX][NUM_PROBAS];
    190 typedef uint16_t CostArray[NUM_CTX][MAX_VARIABLE_LEVEL + 1];
    191 typedef double LFStats[NUM_MB_SEGMENTS][MAX_LF_LEVELS];  // filter stats
    192 
    193 typedef struct VP8Encoder VP8Encoder;
    194 
    195 // segment features
    196 typedef struct {
    197   int num_segments_;      // Actual number of segments. 1 segment only = unused.
    198   int update_map_;        // whether to update the segment map or not.
    199                           // must be 0 if there's only 1 segment.
    200   int size_;              // bit-cost for transmitting the segment map
    201 } VP8SegmentHeader;
    202 
    203 // Struct collecting all frame-persistent probabilities.
    204 typedef struct {
    205   uint8_t segments_[3];     // probabilities for segment tree
    206   uint8_t skip_proba_;      // final probability of being skipped.
    207   ProbaArray coeffs_[NUM_TYPES][NUM_BANDS];      // 924 bytes
    208   StatsArray stats_[NUM_TYPES][NUM_BANDS];       // 4224 bytes
    209   CostArray level_cost_[NUM_TYPES][NUM_BANDS];   // 11.4k
    210   int dirty_;               // if true, need to call VP8CalculateLevelCosts()
    211   int use_skip_proba_;      // Note: we always use skip_proba for now.
    212   int nb_skip_;             // number of skipped blocks
    213 } VP8Proba;
    214 
    215 // Filter parameters. Not actually used in the code (we don't perform
    216 // the in-loop filtering), but filled from user's config
    217 typedef struct {
    218   int simple_;             // filtering type: 0=complex, 1=simple
    219   int level_;              // base filter level [0..63]
    220   int sharpness_;          // [0..7]
    221   int i4x4_lf_delta_;      // delta filter level for i4x4 relative to i16x16
    222 } VP8FilterHeader;
    223 
    224 //------------------------------------------------------------------------------
    225 // Informations about the macroblocks.
    226 
    227 typedef struct {
    228   // block type
    229   unsigned int type_:2;     // 0=i4x4, 1=i16x16
    230   unsigned int uv_mode_:2;
    231   unsigned int skip_:1;
    232   unsigned int segment_:2;
    233   uint8_t alpha_;      // quantization-susceptibility
    234 } VP8MBInfo;
    235 
    236 typedef struct VP8Matrix {
    237   uint16_t q_[16];        // quantizer steps
    238   uint16_t iq_[16];       // reciprocals, fixed point.
    239   uint16_t bias_[16];     // rounding bias
    240   uint16_t zthresh_[16];  // value under which a coefficient is zeroed
    241   uint16_t sharpen_[16];  // frequency boosters for slight sharpening
    242 } VP8Matrix;
    243 
    244 typedef struct {
    245   VP8Matrix y1_, y2_, uv_;  // quantization matrices
    246   int alpha_;      // quant-susceptibility, range [-127,127]. Zero is neutral.
    247                    // Lower values indicate a lower risk of blurriness.
    248   int beta_;       // filter-susceptibility, range [0,255].
    249   int quant_;      // final segment quantizer.
    250   int fstrength_;  // final in-loop filtering strength
    251   // reactivities
    252   int lambda_i16_, lambda_i4_, lambda_uv_;
    253   int lambda_mode_, lambda_trellis_, tlambda_;
    254   int lambda_trellis_i16_, lambda_trellis_i4_, lambda_trellis_uv_;
    255 } VP8SegmentInfo;
    256 
    257 // Handy transcient struct to accumulate score and info during RD-optimization
    258 // and mode evaluation.
    259 typedef struct {
    260   score_t D, SD, R, score;    // Distortion, spectral distortion, rate, score.
    261   int16_t y_dc_levels[16];    // Quantized levels for luma-DC, luma-AC, chroma.
    262   int16_t y_ac_levels[16][16];
    263   int16_t uv_levels[4 + 4][16];
    264   int mode_i16;               // mode number for intra16 prediction
    265   uint8_t modes_i4[16];       // mode numbers for intra4 predictions
    266   int mode_uv;                // mode number of chroma prediction
    267   uint32_t nz;                // non-zero blocks
    268 } VP8ModeScore;
    269 
    270 // Iterator structure to iterate through macroblocks, pointing to the
    271 // right neighbouring data (samples, predictions, contexts, ...)
    272 typedef struct {
    273   int x_, y_;                      // current macroblock
    274   int y_offset_, uv_offset_;       // offset to the luma / chroma planes
    275   int y_stride_, uv_stride_;       // respective strides
    276   uint8_t*      yuv_in_;           // borrowed from enc_ (for now)
    277   uint8_t*      yuv_out_;          // ''
    278   uint8_t*      yuv_out2_;         // ''
    279   uint8_t*      yuv_p_;            // ''
    280   VP8Encoder*   enc_;              // back-pointer
    281   VP8MBInfo*    mb_;               // current macroblock
    282   VP8BitWriter* bw_;               // current bit-writer
    283   uint8_t*      preds_;            // intra mode predictors (4x4 blocks)
    284   uint32_t*     nz_;               // non-zero pattern
    285   uint8_t       i4_boundary_[37];  // 32+5 boundary samples needed by intra4x4
    286   uint8_t*      i4_top_;           // pointer to the current top boundary sample
    287   int           i4_;               // current intra4x4 mode being tested
    288   int           top_nz_[9];        // top-non-zero context.
    289   int           left_nz_[9];       // left-non-zero. left_nz[8] is independent.
    290   uint64_t      bit_count_[4][3];  // bit counters for coded levels.
    291   uint64_t      luma_bits_;        // macroblock bit-cost for luma
    292   uint64_t      uv_bits_;          // macroblock bit-cost for chroma
    293   LFStats*      lf_stats_;         // filter stats (borrowed from enc_)
    294   int           do_trellis_;       // if true, perform extra level optimisation
    295   int           done_;             // true when scan is finished
    296   int           percent0_;         // saved initial progress percent
    297 } VP8EncIterator;
    298 
    299   // in iterator.c
    300 // must be called first.
    301 void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it);
    302 // restart a scan.
    303 void VP8IteratorReset(VP8EncIterator* const it);
    304 // import samples from source
    305 void VP8IteratorImport(const VP8EncIterator* const it);
    306 // export decimated samples
    307 void VP8IteratorExport(const VP8EncIterator* const it);
    308 // go to next macroblock. Returns !done_. If *block_to_save is non-null, will
    309 // save the boundary values to top_/left_ arrays. block_to_save can be
    310 // it->yuv_out_ or it->yuv_in_.
    311 int VP8IteratorNext(VP8EncIterator* const it,
    312                     const uint8_t* const block_to_save);
    313 // Report progression based on macroblock rows. Return 0 for user-abort request.
    314 int VP8IteratorProgress(const VP8EncIterator* const it,
    315                         int final_delta_percent);
    316 // Intra4x4 iterations
    317 void VP8IteratorStartI4(VP8EncIterator* const it);
    318 // returns true if not done.
    319 int VP8IteratorRotateI4(VP8EncIterator* const it,
    320                         const uint8_t* const yuv_out);
    321 
    322 // Non-zero context setup/teardown
    323 void VP8IteratorNzToBytes(VP8EncIterator* const it);
    324 void VP8IteratorBytesToNz(VP8EncIterator* const it);
    325 
    326 // Helper functions to set mode properties
    327 void VP8SetIntra16Mode(const VP8EncIterator* const it, int mode);
    328 void VP8SetIntra4Mode(const VP8EncIterator* const it, const uint8_t* modes);
    329 void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode);
    330 void VP8SetSkip(const VP8EncIterator* const it, int skip);
    331 void VP8SetSegment(const VP8EncIterator* const it, int segment);
    332 
    333 //------------------------------------------------------------------------------
    334 // Paginated token buffer
    335 
    336 typedef struct VP8Tokens VP8Tokens;  // struct details in token.c
    337 
    338 typedef struct {
    339 #if !defined(DISABLE_TOKEN_BUFFER)
    340   VP8Tokens* pages_;        // first page
    341   VP8Tokens** last_page_;   // last page
    342   uint16_t* tokens_;        // set to (*last_page_)->tokens_
    343   int left_;          // how many free tokens left before the page is full.
    344 #endif
    345   int error_;         // true in case of malloc error
    346 } VP8TBuffer;
    347 
    348 void VP8TBufferInit(VP8TBuffer* const b);    // initialize an empty buffer
    349 void VP8TBufferClear(VP8TBuffer* const b);   // de-allocate pages memory
    350 
    351 #if !defined(DISABLE_TOKEN_BUFFER)
    352 
    353 // Finalizes bitstream when probabilities are known.
    354 // Deletes the allocated token memory if final_pass is true.
    355 int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,
    356                   const uint8_t* const probas, int final_pass);
    357 
    358 // record the coding of coefficients without knowing the probabilities yet
    359 int VP8RecordCoeffTokens(int ctx, int coeff_type, int first, int last,
    360                          const int16_t* const coeffs,
    361                          VP8TBuffer* const tokens);
    362 
    363 // unused for now
    364 void VP8TokenToStats(const VP8TBuffer* const b, proba_t* const stats);
    365 
    366 #endif  // !DISABLE_TOKEN_BUFFER
    367 
    368 //------------------------------------------------------------------------------
    369 // VP8Encoder
    370 
    371 struct VP8Encoder {
    372   const WebPConfig* config_;    // user configuration and parameters
    373   WebPPicture* pic_;            // input / output picture
    374 
    375   // headers
    376   VP8FilterHeader   filter_hdr_;     // filtering information
    377   VP8SegmentHeader  segment_hdr_;    // segment information
    378 
    379   int profile_;                      // VP8's profile, deduced from Config.
    380 
    381   // dimension, in macroblock units.
    382   int mb_w_, mb_h_;
    383   int preds_w_;   // stride of the *preds_ prediction plane (=4*mb_w + 1)
    384 
    385   // number of partitions (1, 2, 4 or 8 = MAX_NUM_PARTITIONS)
    386   int num_parts_;
    387 
    388   // per-partition boolean decoders.
    389   VP8BitWriter bw_;                         // part0
    390   VP8BitWriter parts_[MAX_NUM_PARTITIONS];  // token partitions
    391   VP8TBuffer tokens_;                       // token buffer
    392 
    393   int percent_;                             // for progress
    394 
    395   // transparency blob
    396   int has_alpha_;
    397   uint8_t* alpha_data_;       // non-NULL if transparency is present
    398   uint32_t alpha_data_size_;
    399   WebPWorker alpha_worker_;
    400 
    401   // enhancement layer
    402   int use_layer_;
    403   VP8BitWriter layer_bw_;
    404   uint8_t* layer_data_;
    405   size_t layer_data_size_;
    406 
    407   // quantization info (one set of DC/AC dequant factor per segment)
    408   VP8SegmentInfo dqm_[NUM_MB_SEGMENTS];
    409   int base_quant_;                 // nominal quantizer value. Only used
    410                                    // for relative coding of segments' quant.
    411   int alpha_;                      // global susceptibility (<=> complexity)
    412   int uv_alpha_;                   // U/V quantization susceptibility
    413   // global offset of quantizers, shared by all segments
    414   int dq_y1_dc_;
    415   int dq_y2_dc_, dq_y2_ac_;
    416   int dq_uv_dc_, dq_uv_ac_;
    417 
    418   // probabilities and statistics
    419   VP8Proba proba_;
    420   uint64_t sse_[4];        // sum of Y/U/V/A squared errors for all macroblocks
    421   uint64_t sse_count_;     // pixel count for the sse_[] stats
    422   int      coded_size_;
    423   int      residual_bytes_[3][4];
    424   int      block_count_[3];
    425 
    426   // quality/speed settings
    427   int method_;               // 0=fastest, 6=best/slowest.
    428   VP8RDLevel rd_opt_level_;  // Deduced from method_.
    429   int max_i4_header_bits_;   // partition #0 safeness factor
    430   int thread_level_;         // derived from config->thread_level
    431   int do_search_;            // derived from config->target_XXX
    432   int use_tokens_;           // if true, use token buffer
    433 
    434   // Memory
    435   VP8MBInfo* mb_info_;   // contextual macroblock infos (mb_w_ + 1)
    436   uint8_t*   preds_;     // predictions modes: (4*mb_w+1) * (4*mb_h+1)
    437   uint32_t*  nz_;        // non-zero bit context: mb_w+1
    438   uint8_t*   yuv_in_;    // input samples
    439   uint8_t*   yuv_out_;   // output samples
    440   uint8_t*   yuv_out2_;  // secondary scratch out-buffer. swapped with yuv_out_.
    441   uint8_t*   yuv_p_;     // scratch buffer for prediction
    442   uint8_t   *y_top_;     // top luma samples.
    443   uint8_t   *uv_top_;    // top u/v samples.
    444                          // U and V are packed into 16 pixels (8 U + 8 V)
    445   uint8_t   *y_left_;    // left luma samples (adressable from index -1 to 15).
    446   uint8_t   *u_left_;    // left u samples (adressable from index -1 to 7)
    447   uint8_t   *v_left_;    // left v samples (adressable from index -1 to 7)
    448 
    449   LFStats   *lf_stats_;  // autofilter stats (if NULL, autofilter is off)
    450 };
    451 
    452 //------------------------------------------------------------------------------
    453 // internal functions. Not public.
    454 
    455   // in tree.c
    456 extern const uint8_t VP8CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
    457 extern const uint8_t
    458     VP8CoeffsUpdateProba[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
    459 // Reset the token probabilities to their initial (default) values
    460 void VP8DefaultProbas(VP8Encoder* const enc);
    461 // Write the token probabilities
    462 void VP8WriteProbas(VP8BitWriter* const bw, const VP8Proba* const probas);
    463 // Writes the partition #0 modes (that is: all intra modes)
    464 void VP8CodeIntraModes(VP8Encoder* const enc);
    465 
    466   // in syntax.c
    467 // Generates the final bitstream by coding the partition0 and headers,
    468 // and appending an assembly of all the pre-coded token partitions.
    469 // Return true if everything is ok.
    470 int VP8EncWrite(VP8Encoder* const enc);
    471 // Release memory allocated for bit-writing in VP8EncLoop & seq.
    472 void VP8EncFreeBitWriters(VP8Encoder* const enc);
    473 
    474   // in frame.c
    475 extern const uint8_t VP8EncBands[16 + 1];
    476 extern const uint8_t VP8Cat3[];
    477 extern const uint8_t VP8Cat4[];
    478 extern const uint8_t VP8Cat5[];
    479 extern const uint8_t VP8Cat6[];
    480 
    481 // Form all the four Intra16x16 predictions in the yuv_p_ cache
    482 void VP8MakeLuma16Preds(const VP8EncIterator* const it);
    483 // Form all the four Chroma8x8 predictions in the yuv_p_ cache
    484 void VP8MakeChroma8Preds(const VP8EncIterator* const it);
    485 // Form all the ten Intra4x4 predictions in the yuv_p_ cache
    486 // for the 4x4 block it->i4_
    487 void VP8MakeIntra4Preds(const VP8EncIterator* const it);
    488 // Rate calculation
    489 int VP8GetCostLuma16(VP8EncIterator* const it, const VP8ModeScore* const rd);
    490 int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]);
    491 int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd);
    492 // Main coding calls
    493 int VP8EncLoop(VP8Encoder* const enc);
    494 int VP8EncTokenLoop(VP8Encoder* const enc);
    495 
    496   // in webpenc.c
    497 // Assign an error code to a picture. Return false for convenience.
    498 int WebPEncodingSetError(const WebPPicture* const pic, WebPEncodingError error);
    499 int WebPReportProgress(const WebPPicture* const pic,
    500                        int percent, int* const percent_store);
    501 
    502   // in analysis.c
    503 // Main analysis loop. Decides the segmentations and complexity.
    504 // Assigns a first guess for Intra16 and uvmode_ prediction modes.
    505 int VP8EncAnalyze(VP8Encoder* const enc);
    506 
    507   // in quant.c
    508 // Sets up segment's quantization values, base_quant_ and filter strengths.
    509 void VP8SetSegmentParams(VP8Encoder* const enc, float quality);
    510 // Pick best modes and fills the levels. Returns true if skipped.
    511 int VP8Decimate(VP8EncIterator* const it, VP8ModeScore* const rd,
    512                 VP8RDLevel rd_opt);
    513 
    514   // in alpha.c
    515 void VP8EncInitAlpha(VP8Encoder* const enc);    // initialize alpha compression
    516 int VP8EncStartAlpha(VP8Encoder* const enc);    // start alpha coding process
    517 int VP8EncFinishAlpha(VP8Encoder* const enc);   // finalize compressed data
    518 int VP8EncDeleteAlpha(VP8Encoder* const enc);   // delete compressed data
    519 
    520   // in layer.c
    521 void VP8EncInitLayer(VP8Encoder* const enc);     // init everything
    522 void VP8EncCodeLayerBlock(VP8EncIterator* it);   // code one more macroblock
    523 int VP8EncFinishLayer(VP8Encoder* const enc);    // finalize coding
    524 void VP8EncDeleteLayer(VP8Encoder* enc);         // reclaim memory
    525 
    526   // in filter.c
    527 
    528 // SSIM utils
    529 typedef struct {
    530   double w, xm, ym, xxm, xym, yym;
    531 } DistoStats;
    532 void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst);
    533 void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
    534                             const uint8_t* src2, int stride2,
    535                             int W, int H, DistoStats* const stats);
    536 double VP8SSIMGet(const DistoStats* const stats);
    537 double VP8SSIMGetSquaredError(const DistoStats* const stats);
    538 
    539 // autofilter
    540 void VP8InitFilter(VP8EncIterator* const it);
    541 void VP8StoreFilterStats(VP8EncIterator* const it);
    542 void VP8AdjustFilterStrength(VP8EncIterator* const it);
    543 
    544 //------------------------------------------------------------------------------
    545 
    546 #if defined(__cplusplus) || defined(c_plusplus)
    547 }    // extern "C"
    548 #endif
    549 
    550 #endif  /* WEBP_ENC_VP8ENCI_H_ */
    551