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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.
12 // Author: Skal (pascal.massimino@gmail.com)
14 #ifndef WEBP_ENC_VP8ENCI_H_
15 #define WEBP_ENC_VP8ENCI_H_
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"
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
27 //------------------------------------------------------------------------------
28 // Various defines and enums
30 // version numbers
31 #define ENC_MAJ_VERSION 0
32 #define ENC_MIN_VERSION 4
33 #define ENC_REV_VERSION 3
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
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
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)
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;
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 ('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)
133 extern const int VP8Scan[16]; // 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];
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)
162 typedef int64_t score_t; // type used for scores, rate, distortion
163 // Note that MAX_COST is not the maximum allowed by sizeof(score_t),
164 // in order to allow overflowing computations.
165 #define MAX_COST ((score_t)0x7fffffffffffffLL)
167 #define QFIX 17
168 #define BIAS(b) ((b) << (QFIX - 8))
169 // Fun fact: this is the _only_ line where we're actually being lossy and
170 // discarding bits.
171 static WEBP_INLINE int QUANTDIV(uint32_t n, uint32_t iQ, uint32_t B) {
172 return (int)((n * iQ + B) >> QFIX);
175 // size of histogram used by CollectHistogram.
176 #define MAX_COEFF_THRESH 31
177 typedef struct VP8Histogram VP8Histogram;
178 struct VP8Histogram {
179 // TODO(skal): we only need to store the max_value and last_non_zero actually.
180 int distribution[MAX_COEFF_THRESH + 1];
183 // Uncomment the following to remove token-buffer code:
184 // #define DISABLE_TOKEN_BUFFER
186 //------------------------------------------------------------------------------
187 // Headers
189 typedef uint32_t proba_t; // 16b + 16b
190 typedef uint8_t ProbaArray[NUM_CTX][NUM_PROBAS];
191 typedef proba_t StatsArray[NUM_CTX][NUM_PROBAS];
192 typedef uint16_t CostArray[NUM_CTX][MAX_VARIABLE_LEVEL + 1];
193 typedef double LFStats[NUM_MB_SEGMENTS][MAX_LF_LEVELS]; // filter stats
195 typedef struct VP8Encoder VP8Encoder;
197 // segment features
198 typedef struct {
199 int num_segments_; // Actual number of segments. 1 segment only = unused.
200 int update_map_; // whether to update the segment map or not.
201 // must be 0 if there's only 1 segment.
202 int size_; // bit-cost for transmitting the segment map
203 } VP8SegmentHeader;
205 // Struct collecting all frame-persistent probabilities.
206 typedef struct {
207 uint8_t segments_[3]; // probabilities for segment tree
208 uint8_t skip_proba_; // final probability of being skipped.
209 ProbaArray coeffs_[NUM_TYPES][NUM_BANDS]; // 1056 bytes
210 StatsArray stats_[NUM_TYPES][NUM_BANDS]; // 4224 bytes
211 CostArray level_cost_[NUM_TYPES][NUM_BANDS]; // 13056 bytes
212 int dirty_; // if true, need to call VP8CalculateLevelCosts()
213 int use_skip_proba_; // Note: we always use skip_proba for now.
214 int nb_skip_; // number of skipped blocks
215 } VP8Proba;
217 // Filter parameters. Not actually used in the code (we don't perform
218 // the in-loop filtering), but filled from user's config
219 typedef struct {
220 int simple_; // filtering type: 0=complex, 1=simple
221 int level_; // base filter level [0..63]
222 int sharpness_; // [0..7]
223 int i4x4_lf_delta_; // delta filter level for i4x4 relative to i16x16
224 } VP8FilterHeader;
226 //------------------------------------------------------------------------------
227 // Informations about the macroblocks.
229 typedef struct {
230 // block type
231 unsigned int type_:2; // 0=i4x4, 1=i16x16
232 unsigned int uv_mode_:2;
233 unsigned int skip_:1;
234 unsigned int segment_:2;
235 uint8_t alpha_; // quantization-susceptibility
236 } VP8MBInfo;
238 typedef struct VP8Matrix {
239 uint16_t q_[16]; // quantizer steps
240 uint16_t iq_[16]; // reciprocals, fixed point.
241 uint32_t bias_[16]; // rounding bias
242 uint32_t zthresh_[16]; // value below which a coefficient is zeroed
243 uint16_t sharpen_[16]; // frequency boosters for slight sharpening
244 } VP8Matrix;
246 typedef struct {
247 VP8Matrix y1_, y2_, uv_; // quantization matrices
248 int alpha_; // quant-susceptibility, range [-127,127]. Zero is neutral.
249 // Lower values indicate a lower risk of blurriness.
250 int beta_; // filter-susceptibility, range [0,255].
251 int quant_; // final segment quantizer.
252 int fstrength_; // final in-loop filtering strength
253 int max_edge_; // max edge delta (for filtering strength)
254 int min_disto_; // minimum distortion required to trigger filtering record
255 // reactivities
256 int lambda_i16_, lambda_i4_, lambda_uv_;
257 int lambda_mode_, lambda_trellis_, tlambda_;
258 int lambda_trellis_i16_, lambda_trellis_i4_, lambda_trellis_uv_;
259 } VP8SegmentInfo;
261 // Handy transient struct to accumulate score and info during RD-optimization
262 // and mode evaluation.
263 typedef struct {
264 score_t D, SD; // Distortion, spectral distortion
265 score_t H, R, score; // header bits, rate, score.
266 int16_t y_dc_levels[16]; // Quantized levels for luma-DC, luma-AC, chroma.
267 int16_t y_ac_levels[16][16];
268 int16_t uv_levels[4 + 4][16];
269 int mode_i16; // mode number for intra16 prediction
270 uint8_t modes_i4[16]; // mode numbers for intra4 predictions
271 int mode_uv; // mode number of chroma prediction
272 uint32_t nz; // non-zero blocks
273 } VP8ModeScore;
275 // Iterator structure to iterate through macroblocks, pointing to the
276 // right neighbouring data (samples, predictions, contexts, ...)
277 typedef struct {
278 int x_, y_; // current macroblock
279 int y_stride_, uv_stride_; // respective strides
280 uint8_t* yuv_in_; // input samples
281 uint8_t* yuv_out_; // output samples
282 uint8_t* yuv_out2_; // secondary buffer swapped with yuv_out_.
283 uint8_t* yuv_p_; // scratch buffer for prediction
284 VP8Encoder* enc_; // back-pointer
285 VP8MBInfo* mb_; // current macroblock
286 VP8BitWriter* bw_; // current bit-writer
287 uint8_t* preds_; // intra mode predictors (4x4 blocks)
288 uint32_t* nz_; // non-zero pattern
289 uint8_t i4_boundary_[37]; // 32+5 boundary samples needed by intra4x4
290 uint8_t* i4_top_; // pointer to the current top boundary sample
291 int i4_; // current intra4x4 mode being tested
292 int top_nz_[9]; // top-non-zero context.
293 int left_nz_[9]; // left-non-zero. left_nz[8] is independent.
294 uint64_t bit_count_[4][3]; // bit counters for coded levels.
295 uint64_t luma_bits_; // macroblock bit-cost for luma
296 uint64_t uv_bits_; // macroblock bit-cost for chroma
297 LFStats* lf_stats_; // filter stats (borrowed from enc_)
298 int do_trellis_; // if true, perform extra level optimisation
299 int count_down_; // number of mb still to be processed
300 int count_down0_; // starting counter value (for progress)
301 int percent0_; // saved initial progress percent
303 uint8_t* y_left_; // left luma samples (addressable from index -1 to 15).
304 uint8_t* u_left_; // left u samples (addressable from index -1 to 7)
305 uint8_t* v_left_; // left v samples (addressable from index -1 to 7)
307 uint8_t* y_top_; // top luma samples at position 'x_'
308 uint8_t* uv_top_; // top u/v samples at position 'x_', packed as 16 bytes
310 // memory for storing y/u/v_left_ and yuv_in_/out_*
311 uint8_t yuv_left_mem_[17 + 16 + 16 + 8 + ALIGN_CST]; // memory for *_left_
312 uint8_t yuv_mem_[3 * YUV_SIZE + PRED_SIZE + ALIGN_CST]; // memory for yuv_*
313 } VP8EncIterator;
315 // in iterator.c
316 // must be called first
317 void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it);
318 // restart a scan
319 void VP8IteratorReset(VP8EncIterator* const it);
320 // reset iterator position to row 'y'
321 void VP8IteratorSetRow(VP8EncIterator* const it, int y);
322 // set count down (=number of iterations to go)
323 void VP8IteratorSetCountDown(VP8EncIterator* const it, int count_down);
324 // return true if iteration is finished
325 int VP8IteratorIsDone(const VP8EncIterator* const it);
326 // Import uncompressed samples from source.
327 // If tmp_32 is not NULL, import boundary samples too.
328 // tmp_32 is a 32-bytes scratch buffer that must be aligned in memory.
329 void VP8IteratorImport(VP8EncIterator* const it, uint8_t* tmp_32);
330 // export decimated samples
331 void VP8IteratorExport(const VP8EncIterator* const it);
332 // go to next macroblock. Returns false if not finished.
333 int VP8IteratorNext(VP8EncIterator* const it);
334 // save the yuv_out_ boundary values to top_/left_ arrays for next iterations.
335 void VP8IteratorSaveBoundary(VP8EncIterator* const it);
336 // Report progression based on macroblock rows. Return 0 for user-abort request.
337 int VP8IteratorProgress(const VP8EncIterator* const it,
338 int final_delta_percent);
339 // Intra4x4 iterations
340 void VP8IteratorStartI4(VP8EncIterator* const it);
341 // returns true if not done.
342 int VP8IteratorRotateI4(VP8EncIterator* const it,
343 const uint8_t* const yuv_out);
345 // Non-zero context setup/teardown
346 void VP8IteratorNzToBytes(VP8EncIterator* const it);
347 void VP8IteratorBytesToNz(VP8EncIterator* const it);
349 // Helper functions to set mode properties
350 void VP8SetIntra16Mode(const VP8EncIterator* const it, int mode);
351 void VP8SetIntra4Mode(const VP8EncIterator* const it, const uint8_t* modes);
352 void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode);
353 void VP8SetSkip(const VP8EncIterator* const it, int skip);
354 void VP8SetSegment(const VP8EncIterator* const it, int segment);
356 //------------------------------------------------------------------------------
357 // Paginated token buffer
359 typedef struct VP8Tokens VP8Tokens; // struct details in token.c
361 typedef struct {
362 #if !defined(DISABLE_TOKEN_BUFFER)
363 VP8Tokens* pages_; // first page
364 VP8Tokens** last_page_; // last page
365 uint16_t* tokens_; // set to (*last_page_)->tokens_
366 int left_; // how many free tokens left before the page is full
367 int page_size_; // number of tokens per page
368 #endif
369 int error_; // true in case of malloc error
370 } VP8TBuffer;
372 // initialize an empty buffer
373 void VP8TBufferInit(VP8TBuffer* const b, int page_size);
374 void VP8TBufferClear(VP8TBuffer* const b); // de-allocate pages memory
376 #if !defined(DISABLE_TOKEN_BUFFER)
378 // Finalizes bitstream when probabilities are known.
379 // Deletes the allocated token memory if final_pass is true.
380 int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,
381 const uint8_t* const probas, int final_pass);
383 // record the coding of coefficients without knowing the probabilities yet
384 int VP8RecordCoeffTokens(int ctx, int coeff_type, int first, int last,
385 const int16_t* const coeffs,
386 VP8TBuffer* const tokens);
388 // Estimate the final coded size given a set of 'probas'.
389 size_t VP8EstimateTokenSize(VP8TBuffer* const b, const uint8_t* const probas);
391 // unused for now
392 void VP8TokenToStats(const VP8TBuffer* const b, proba_t* const stats);
394 #endif // !DISABLE_TOKEN_BUFFER
396 //------------------------------------------------------------------------------
397 // VP8Encoder
399 struct VP8Encoder {
400 const WebPConfig* config_; // user configuration and parameters
401 WebPPicture* pic_; // input / output picture
403 // headers
404 VP8FilterHeader filter_hdr_; // filtering information
405 VP8SegmentHeader segment_hdr_; // segment information
407 int profile_; // VP8's profile, deduced from Config.
409 // dimension, in macroblock units.
410 int mb_w_, mb_h_;
411 int preds_w_; // stride of the *preds_ prediction plane (=4*mb_w + 1)
413 // number of partitions (1, 2, 4 or 8 = MAX_NUM_PARTITIONS)
414 int num_parts_;
416 // per-partition boolean decoders.
417 VP8BitWriter bw_; // part0
418 VP8BitWriter parts_[MAX_NUM_PARTITIONS]; // token partitions
419 VP8TBuffer tokens_; // token buffer
421 int percent_; // for progress
423 // transparency blob
424 int has_alpha_;
425 uint8_t* alpha_data_; // non-NULL if transparency is present
426 uint32_t alpha_data_size_;
427 WebPWorker alpha_worker_;
429 // quantization info (one set of DC/AC dequant factor per segment)
430 VP8SegmentInfo dqm_[NUM_MB_SEGMENTS];
431 int base_quant_; // nominal quantizer value. Only used
432 // for relative coding of segments' quant.
433 int alpha_; // global susceptibility (<=> complexity)
434 int uv_alpha_; // U/V quantization susceptibility
435 // global offset of quantizers, shared by all segments
436 int dq_y1_dc_;
437 int dq_y2_dc_, dq_y2_ac_;
438 int dq_uv_dc_, dq_uv_ac_;
440 // probabilities and statistics
441 VP8Proba proba_;
442 uint64_t sse_[4]; // sum of Y/U/V/A squared errors for all macroblocks
443 uint64_t sse_count_; // pixel count for the sse_[] stats
444 int coded_size_;
445 int residual_bytes_[3][4];
446 int block_count_[3];
448 // quality/speed settings
449 int method_; // 0=fastest, 6=best/slowest.
450 VP8RDLevel rd_opt_level_; // Deduced from method_.
451 int max_i4_header_bits_; // partition #0 safeness factor
452 int thread_level_; // derived from config->thread_level
453 int do_search_; // derived from config->target_XXX
454 int use_tokens_; // if true, use token buffer
456 // Memory
457 VP8MBInfo* mb_info_; // contextual macroblock infos (mb_w_ + 1)
458 uint8_t* preds_; // predictions modes: (4*mb_w+1) * (4*mb_h+1)
459 uint32_t* nz_; // non-zero bit context: mb_w+1
460 uint8_t* y_top_; // top luma samples.
461 uint8_t* uv_top_; // top u/v samples.
462 // U and V are packed into 16 bytes (8 U + 8 V)
463 LFStats* lf_stats_; // autofilter stats (if NULL, autofilter is off)
466 //------------------------------------------------------------------------------
467 // internal functions. Not public.
469 // in tree.c
470 extern const uint8_t VP8CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
471 extern const uint8_t
472 VP8CoeffsUpdateProba[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
473 // Reset the token probabilities to their initial (default) values
474 void VP8DefaultProbas(VP8Encoder* const enc);
475 // Write the token probabilities
476 void VP8WriteProbas(VP8BitWriter* const bw, const VP8Proba* const probas);
477 // Writes the partition #0 modes (that is: all intra modes)
478 void VP8CodeIntraModes(VP8Encoder* const enc);
480 // in syntax.c
481 // Generates the final bitstream by coding the partition0 and headers,
482 // and appending an assembly of all the pre-coded token partitions.
483 // Return true if everything is ok.
484 int VP8EncWrite(VP8Encoder* const enc);
485 // Release memory allocated for bit-writing in VP8EncLoop & seq.
486 void VP8EncFreeBitWriters(VP8Encoder* const enc);
488 // in frame.c
489 extern const uint8_t VP8EncBands[16 + 1];
490 extern const uint8_t VP8Cat3[];
491 extern const uint8_t VP8Cat4[];
492 extern const uint8_t VP8Cat5[];
493 extern const uint8_t VP8Cat6[];
495 // Form all the four Intra16x16 predictions in the yuv_p_ cache
496 void VP8MakeLuma16Preds(const VP8EncIterator* const it);
497 // Form all the four Chroma8x8 predictions in the yuv_p_ cache
498 void VP8MakeChroma8Preds(const VP8EncIterator* const it);
499 // Form all the ten Intra4x4 predictions in the yuv_p_ cache
500 // for the 4x4 block it->i4_
501 void VP8MakeIntra4Preds(const VP8EncIterator* const it);
502 // Rate calculation
503 int VP8GetCostLuma16(VP8EncIterator* const it, const VP8ModeScore* const rd);
504 int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]);
505 int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd);
506 // Main coding calls
507 int VP8EncLoop(VP8Encoder* const enc);
508 int VP8EncTokenLoop(VP8Encoder* const enc);
510 // in webpenc.c
511 // Assign an error code to a picture. Return false for convenience.
512 int WebPEncodingSetError(const WebPPicture* const pic, WebPEncodingError error);
513 int WebPReportProgress(const WebPPicture* const pic,
514 int percent, int* const percent_store);
516 // in analysis.c
517 // Main analysis loop. Decides the segmentations and complexity.
518 // Assigns a first guess for Intra16 and uvmode_ prediction modes.
519 int VP8EncAnalyze(VP8Encoder* const enc);
521 // in quant.c
522 // Sets up segment's quantization values, base_quant_ and filter strengths.
523 void VP8SetSegmentParams(VP8Encoder* const enc, float quality);
524 // Pick best modes and fills the levels. Returns true if skipped.
525 int VP8Decimate(VP8EncIterator* const it, VP8ModeScore* const rd,
526 VP8RDLevel rd_opt);
528 // in alpha.c
529 void VP8EncInitAlpha(VP8Encoder* const enc); // initialize alpha compression
530 int VP8EncStartAlpha(VP8Encoder* const enc); // start alpha coding process
531 int VP8EncFinishAlpha(VP8Encoder* const enc); // finalize compressed data
532 int VP8EncDeleteAlpha(VP8Encoder* const enc); // delete compressed data
534 // in filter.c
536 // SSIM utils
537 typedef struct {
538 double w, xm, ym, xxm, xym, yym;
539 } DistoStats;
540 void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst);
541 void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
542 const uint8_t* src2, int stride2,
543 int W, int H, DistoStats* const stats);
544 double VP8SSIMGet(const DistoStats* const stats);
545 double VP8SSIMGetSquaredError(const DistoStats* const stats);
547 // autofilter
548 void VP8InitFilter(VP8EncIterator* const it);
549 void VP8StoreFilterStats(VP8EncIterator* const it);
550 void VP8AdjustFilterStrength(VP8EncIterator* const it);
552 // returns the approximate filtering strength needed to smooth a edge
553 // step of 'delta', given a sharpness parameter 'sharpness'.
554 int VP8FilterStrengthFromDelta(int sharpness, int delta);
556 // misc utils for picture_*.c:
558 // Remove reference to the ARGB/YUVA buffer (doesn't free anything).
559 void WebPPictureResetBuffers(WebPPicture* const picture);
561 // Allocates ARGB buffer of given dimension (previous one is always free'd).
562 // Preserves the YUV(A) buffer. Returns false in case of error (invalid param,
563 // out-of-memory).
564 int WebPPictureAllocARGB(WebPPicture* const picture, int width, int height);
566 // Allocates YUVA buffer of given dimension (previous one is always free'd).
567 // Uses picture->csp to determine whether an alpha buffer is needed.
568 // Preserves the ARGB buffer.
569 // Returns false in case of error (invalid param, out-of-memory).
570 int WebPPictureAllocYUVA(WebPPicture* const picture, int width, int height);
572 //------------------------------------------------------------------------------
574 #if WEBP_ENCODER_ABI_VERSION <= 0x0203
575 void WebPMemoryWriterClear(WebPMemoryWriter* writer);
576 #endif
578 #ifdef __cplusplus
579 } // extern "C"
580 #endif
582 #endif /* WEBP_ENC_VP8ENCI_H_ */