1 // Copyright 2010 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 // VP8 decoder: internal header. 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #ifndef WEBP_DEC_VP8I_H_ 15 #define WEBP_DEC_VP8I_H_ 16 17 #include <string.h> // for memcpy() 18 #include "./vp8li.h" 19 #include "../utils/bit_reader.h" 20 #include "../utils/random.h" 21 #include "../utils/thread.h" 22 #include "../dsp/dsp.h" 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif 27 28 //------------------------------------------------------------------------------ 29 // Various defines and enums 30 31 // version numbers 32 #define DEC_MAJ_VERSION 0 33 #define DEC_MIN_VERSION 4 34 #define DEC_REV_VERSION 3 35 36 // intra prediction modes 37 enum { B_DC_PRED = 0, // 4x4 modes 38 B_TM_PRED, 39 B_VE_PRED, 40 B_HE_PRED, 41 B_RD_PRED, 42 B_VR_PRED, 43 B_LD_PRED, 44 B_VL_PRED, 45 B_HD_PRED, 46 B_HU_PRED, 47 NUM_BMODES = B_HU_PRED + 1 - B_DC_PRED, // = 10 48 49 // Luma16 or UV modes 50 DC_PRED = B_DC_PRED, V_PRED = B_VE_PRED, 51 H_PRED = B_HE_PRED, TM_PRED = B_TM_PRED, 52 B_PRED = NUM_BMODES, // refined I4x4 mode 53 54 // special modes 55 B_DC_PRED_NOTOP = 4, 56 B_DC_PRED_NOLEFT = 5, 57 B_DC_PRED_NOTOPLEFT = 6, 58 NUM_B_DC_MODES = 7 }; 59 60 enum { MB_FEATURE_TREE_PROBS = 3, 61 NUM_MB_SEGMENTS = 4, 62 NUM_REF_LF_DELTAS = 4, 63 NUM_MODE_LF_DELTAS = 4, // I4x4, ZERO, *, SPLIT 64 MAX_NUM_PARTITIONS = 8, 65 // Probabilities 66 NUM_TYPES = 4, 67 NUM_BANDS = 8, 68 NUM_CTX = 3, 69 NUM_PROBAS = 11, 70 NUM_MV_PROBAS = 19 }; 71 72 // YUV-cache parameters. 73 // Constraints are: We need to store one 16x16 block of luma samples (y), 74 // and two 8x8 chroma blocks (u/v). These are better be 16-bytes aligned, 75 // in order to be SIMD-friendly. We also need to store the top, left and 76 // top-left samples (from previously decoded blocks), along with four 77 // extra top-right samples for luma (intra4x4 prediction only). 78 // One possible layout is, using 32 * (17 + 9) bytes: 79 // 80 // .+------ <- only 1 pixel high 81 // .|yyyyt. 82 // .|yyyyt. 83 // .|yyyyt. 84 // .|yyyy.. 85 // .+--.+-- <- only 1 pixel high 86 // .|uu.|vv 87 // .|uu.|vv 88 // 89 // Every character is a 4x4 block, with legend: 90 // '.' = unused 91 // 'y' = y-samples 'u' = u-samples 'v' = u-samples 92 // '|' = left sample, '-' = top sample, '+' = top-left sample 93 // 't' = extra top-right sample for 4x4 modes 94 // With this layout, BPS (=Bytes Per Scan-line) is one cacheline size. 95 #define BPS 32 // this is the common stride used by yuv[] 96 #define YUV_SIZE (BPS * 17 + BPS * 9) 97 #define Y_SIZE (BPS * 17) 98 #define Y_OFF (BPS * 1 + 8) 99 #define U_OFF (Y_OFF + BPS * 16 + BPS) 100 #define V_OFF (U_OFF + 16) 101 102 // minimal width under which lossy multi-threading is always disabled 103 #define MIN_WIDTH_FOR_THREADS 512 104 105 //------------------------------------------------------------------------------ 106 // Headers 107 108 typedef struct { 109 uint8_t key_frame_; 110 uint8_t profile_; 111 uint8_t show_; 112 uint32_t partition_length_; 113 } VP8FrameHeader; 114 115 typedef struct { 116 uint16_t width_; 117 uint16_t height_; 118 uint8_t xscale_; 119 uint8_t yscale_; 120 uint8_t colorspace_; // 0 = YCbCr 121 uint8_t clamp_type_; 122 } VP8PictureHeader; 123 124 // segment features 125 typedef struct { 126 int use_segment_; 127 int update_map_; // whether to update the segment map or not 128 int absolute_delta_; // absolute or delta values for quantizer and filter 129 int8_t quantizer_[NUM_MB_SEGMENTS]; // quantization changes 130 int8_t filter_strength_[NUM_MB_SEGMENTS]; // filter strength for segments 131 } VP8SegmentHeader; 132 133 134 // probas associated to one of the contexts 135 typedef uint8_t VP8ProbaArray[NUM_PROBAS]; 136 137 typedef struct { // all the probas associated to one band 138 VP8ProbaArray probas_[NUM_CTX]; 139 } VP8BandProbas; 140 141 // Struct collecting all frame-persistent probabilities. 142 typedef struct { 143 uint8_t segments_[MB_FEATURE_TREE_PROBS]; 144 // Type: 0:Intra16-AC 1:Intra16-DC 2:Chroma 3:Intra4 145 VP8BandProbas bands_[NUM_TYPES][NUM_BANDS]; 146 } VP8Proba; 147 148 // Filter parameters 149 typedef struct { 150 int simple_; // 0=complex, 1=simple 151 int level_; // [0..63] 152 int sharpness_; // [0..7] 153 int use_lf_delta_; 154 int ref_lf_delta_[NUM_REF_LF_DELTAS]; 155 int mode_lf_delta_[NUM_MODE_LF_DELTAS]; 156 } VP8FilterHeader; 157 158 //------------------------------------------------------------------------------ 159 // Informations about the macroblocks. 160 161 typedef struct { // filter specs 162 uint8_t f_limit_; // filter limit in [3..189], or 0 if no filtering 163 uint8_t f_ilevel_; // inner limit in [1..63] 164 uint8_t f_inner_; // do inner filtering? 165 uint8_t hev_thresh_; // high edge variance threshold in [0..2] 166 } VP8FInfo; 167 168 typedef struct { // Top/Left Contexts used for syntax-parsing 169 uint8_t nz_; // non-zero AC/DC coeffs (4bit for luma + 4bit for chroma) 170 uint8_t nz_dc_; // non-zero DC coeff (1bit) 171 } VP8MB; 172 173 // Dequantization matrices 174 typedef int quant_t[2]; // [DC / AC]. Can be 'uint16_t[2]' too (~slower). 175 typedef struct { 176 quant_t y1_mat_, y2_mat_, uv_mat_; 177 178 int uv_quant_; // U/V quantizer value 179 int dither_; // dithering amplitude (0 = off, max=255) 180 } VP8QuantMatrix; 181 182 // Data needed to reconstruct a macroblock 183 typedef struct { 184 int16_t coeffs_[384]; // 384 coeffs = (16+4+4) * 4*4 185 uint8_t is_i4x4_; // true if intra4x4 186 uint8_t imodes_[16]; // one 16x16 mode (#0) or sixteen 4x4 modes 187 uint8_t uvmode_; // chroma prediction mode 188 // bit-wise info about the content of each sub-4x4 blocks (in decoding order). 189 // Each of the 4x4 blocks for y/u/v is associated with a 2b code according to: 190 // code=0 -> no coefficient 191 // code=1 -> only DC 192 // code=2 -> first three coefficients are non-zero 193 // code=3 -> more than three coefficients are non-zero 194 // This allows to call specialized transform functions. 195 uint32_t non_zero_y_; 196 uint32_t non_zero_uv_; 197 uint8_t dither_; // local dithering strength (deduced from non_zero_*) 198 uint8_t skip_; 199 uint8_t segment_; 200 } VP8MBData; 201 202 // Persistent information needed by the parallel processing 203 typedef struct { 204 int id_; // cache row to process (in [0..2]) 205 int mb_y_; // macroblock position of the row 206 int filter_row_; // true if row-filtering is needed 207 VP8FInfo* f_info_; // filter strengths (swapped with dec->f_info_) 208 VP8MBData* mb_data_; // reconstruction data (swapped with dec->mb_data_) 209 VP8Io io_; // copy of the VP8Io to pass to put() 210 } VP8ThreadContext; 211 212 // Saved top samples, per macroblock. Fits into a cache-line. 213 typedef struct { 214 uint8_t y[16], u[8], v[8]; 215 } VP8TopSamples; 216 217 //------------------------------------------------------------------------------ 218 // VP8Decoder: the main opaque structure handed over to user 219 220 struct VP8Decoder { 221 VP8StatusCode status_; 222 int ready_; // true if ready to decode a picture with VP8Decode() 223 const char* error_msg_; // set when status_ is not OK. 224 225 // Main data source 226 VP8BitReader br_; 227 228 // headers 229 VP8FrameHeader frm_hdr_; 230 VP8PictureHeader pic_hdr_; 231 VP8FilterHeader filter_hdr_; 232 VP8SegmentHeader segment_hdr_; 233 234 // Worker 235 WebPWorker worker_; 236 int mt_method_; // multi-thread method: 0=off, 1=[parse+recon][filter] 237 // 2=[parse][recon+filter] 238 int cache_id_; // current cache row 239 int num_caches_; // number of cached rows of 16 pixels (1, 2 or 3) 240 VP8ThreadContext thread_ctx_; // Thread context 241 242 // dimension, in macroblock units. 243 int mb_w_, mb_h_; 244 245 // Macroblock to process/filter, depending on cropping and filter_type. 246 int tl_mb_x_, tl_mb_y_; // top-left MB that must be in-loop filtered 247 int br_mb_x_, br_mb_y_; // last bottom-right MB that must be decoded 248 249 // number of partitions. 250 int num_parts_; 251 // per-partition boolean decoders. 252 VP8BitReader parts_[MAX_NUM_PARTITIONS]; 253 254 // Dithering strength, deduced from decoding options 255 int dither_; // whether to use dithering or not 256 VP8Random dithering_rg_; // random generator for dithering 257 258 // dequantization (one set of DC/AC dequant factor per segment) 259 VP8QuantMatrix dqm_[NUM_MB_SEGMENTS]; 260 261 // probabilities 262 VP8Proba proba_; 263 int use_skip_proba_; 264 uint8_t skip_p_; 265 266 // Boundary data cache and persistent buffers. 267 uint8_t* intra_t_; // top intra modes values: 4 * mb_w_ 268 uint8_t intra_l_[4]; // left intra modes values 269 270 VP8TopSamples* yuv_t_; // top y/u/v samples 271 272 VP8MB* mb_info_; // contextual macroblock info (mb_w_ + 1) 273 VP8FInfo* f_info_; // filter strength info 274 uint8_t* yuv_b_; // main block for Y/U/V (size = YUV_SIZE) 275 276 uint8_t* cache_y_; // macroblock row for storing unfiltered samples 277 uint8_t* cache_u_; 278 uint8_t* cache_v_; 279 int cache_y_stride_; 280 int cache_uv_stride_; 281 282 // main memory chunk for the above data. Persistent. 283 void* mem_; 284 size_t mem_size_; 285 286 // Per macroblock non-persistent infos. 287 int mb_x_, mb_y_; // current position, in macroblock units 288 VP8MBData* mb_data_; // parsed reconstruction data 289 290 // Filtering side-info 291 int filter_type_; // 0=off, 1=simple, 2=complex 292 VP8FInfo fstrengths_[NUM_MB_SEGMENTS][2]; // precalculated per-segment/type 293 294 // Alpha 295 struct ALPHDecoder* alph_dec_; // alpha-plane decoder object 296 const uint8_t* alpha_data_; // compressed alpha data (if present) 297 size_t alpha_data_size_; 298 int is_alpha_decoded_; // true if alpha_data_ is decoded in alpha_plane_ 299 uint8_t* alpha_plane_; // output. Persistent, contains the whole data. 300 int alpha_dithering_; // derived from decoding options (0=off, 100=full). 301 }; 302 303 //------------------------------------------------------------------------------ 304 // internal functions. Not public. 305 306 // in vp8.c 307 int VP8SetError(VP8Decoder* const dec, 308 VP8StatusCode error, const char* const msg); 309 310 // in tree.c 311 void VP8ResetProba(VP8Proba* const proba); 312 void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec); 313 // parses one row of intra mode data in partition 0, returns !eof 314 int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec); 315 316 // in quant.c 317 void VP8ParseQuant(VP8Decoder* const dec); 318 319 // in frame.c 320 int VP8InitFrame(VP8Decoder* const dec, VP8Io* io); 321 // Call io->setup() and finish setting up scan parameters. 322 // After this call returns, one must always call VP8ExitCritical() with the 323 // same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK 324 // if ok, otherwise sets and returns the error status on *dec. 325 VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io); 326 // Must always be called in pair with VP8EnterCritical(). 327 // Returns false in case of error. 328 int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io); 329 // Return the multi-threading method to use (0=off), depending 330 // on options and bitstream size. Only for lossy decoding. 331 int VP8GetThreadMethod(const WebPDecoderOptions* const options, 332 const WebPHeaderStructure* const headers, 333 int width, int height); 334 // Initialize dithering post-process if needed. 335 void VP8InitDithering(const WebPDecoderOptions* const options, 336 VP8Decoder* const dec); 337 // Process the last decoded row (filtering + output). 338 int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io); 339 // To be called at the start of a new scanline, to initialize predictors. 340 void VP8InitScanline(VP8Decoder* const dec); 341 // Decode one macroblock. Returns false if there is not enough data. 342 int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br); 343 344 // in alpha.c 345 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec, 346 int row, int num_rows); 347 348 //------------------------------------------------------------------------------ 349 350 #ifdef __cplusplus 351 } // extern "C" 352 #endif 353 354 #endif /* WEBP_DEC_VP8I_H_ */ 355
