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@gmail.com) 13 14 #ifndef WEBP_DEC_VP8I_DEC_H_ 15 #define WEBP_DEC_VP8I_DEC_H_ 16 17 #include <string.h> // for memcpy() 18 #include "src/dec/common_dec.h" 19 #include "src/dec/vp8li_dec.h" 20 #include "src/utils/bit_reader_utils.h" 21 #include "src/utils/random_utils.h" 22 #include "src/utils/thread_utils.h" 23 #include "src/dsp/dsp.h" 24 25 #ifdef __cplusplus 26 extern "C" { 27 #endif 28 29 //------------------------------------------------------------------------------ 30 // Various defines and enums 31 32 // version numbers 33 #define DEC_MAJ_VERSION 1 34 #define DEC_MIN_VERSION 0 35 #define DEC_REV_VERSION 2 36 37 // YUV-cache parameters. Cache is 32-bytes wide (= one cacheline). 38 // Constraints are: We need to store one 16x16 block of luma samples (y), 39 // and two 8x8 chroma blocks (u/v). These are better be 16-bytes aligned, 40 // in order to be SIMD-friendly. We also need to store the top, left and 41 // top-left samples (from previously decoded blocks), along with four 42 // extra top-right samples for luma (intra4x4 prediction only). 43 // One possible layout is, using 32 * (17 + 9) bytes: 44 // 45 // .+------ <- only 1 pixel high 46 // .|yyyyt. 47 // .|yyyyt. 48 // .|yyyyt. 49 // .|yyyy.. 50 // .+--.+-- <- only 1 pixel high 51 // .|uu.|vv 52 // .|uu.|vv 53 // 54 // Every character is a 4x4 block, with legend: 55 // '.' = unused 56 // 'y' = y-samples 'u' = u-samples 'v' = u-samples 57 // '|' = left sample, '-' = top sample, '+' = top-left sample 58 // 't' = extra top-right sample for 4x4 modes 59 #define YUV_SIZE (BPS * 17 + BPS * 9) 60 #define Y_OFF (BPS * 1 + 8) 61 #define U_OFF (Y_OFF + BPS * 16 + BPS) 62 #define V_OFF (U_OFF + 16) 63 64 // minimal width under which lossy multi-threading is always disabled 65 #define MIN_WIDTH_FOR_THREADS 512 66 67 //------------------------------------------------------------------------------ 68 // Headers 69 70 typedef struct { 71 uint8_t key_frame_; 72 uint8_t profile_; 73 uint8_t show_; 74 uint32_t partition_length_; 75 } VP8FrameHeader; 76 77 typedef struct { 78 uint16_t width_; 79 uint16_t height_; 80 uint8_t xscale_; 81 uint8_t yscale_; 82 uint8_t colorspace_; // 0 = YCbCr 83 uint8_t clamp_type_; 84 } VP8PictureHeader; 85 86 // segment features 87 typedef struct { 88 int use_segment_; 89 int update_map_; // whether to update the segment map or not 90 int absolute_delta_; // absolute or delta values for quantizer and filter 91 int8_t quantizer_[NUM_MB_SEGMENTS]; // quantization changes 92 int8_t filter_strength_[NUM_MB_SEGMENTS]; // filter strength for segments 93 } VP8SegmentHeader; 94 95 // probas associated to one of the contexts 96 typedef uint8_t VP8ProbaArray[NUM_PROBAS]; 97 98 typedef struct { // all the probas associated to one band 99 VP8ProbaArray probas_[NUM_CTX]; 100 } VP8BandProbas; 101 102 // Struct collecting all frame-persistent probabilities. 103 typedef struct { 104 uint8_t segments_[MB_FEATURE_TREE_PROBS]; 105 // Type: 0:Intra16-AC 1:Intra16-DC 2:Chroma 3:Intra4 106 VP8BandProbas bands_[NUM_TYPES][NUM_BANDS]; 107 const VP8BandProbas* bands_ptr_[NUM_TYPES][16 + 1]; 108 } VP8Proba; 109 110 // Filter parameters 111 typedef struct { 112 int simple_; // 0=complex, 1=simple 113 int level_; // [0..63] 114 int sharpness_; // [0..7] 115 int use_lf_delta_; 116 int ref_lf_delta_[NUM_REF_LF_DELTAS]; 117 int mode_lf_delta_[NUM_MODE_LF_DELTAS]; 118 } VP8FilterHeader; 119 120 //------------------------------------------------------------------------------ 121 // Informations about the macroblocks. 122 123 typedef struct { // filter specs 124 uint8_t f_limit_; // filter limit in [3..189], or 0 if no filtering 125 uint8_t f_ilevel_; // inner limit in [1..63] 126 uint8_t f_inner_; // do inner filtering? 127 uint8_t hev_thresh_; // high edge variance threshold in [0..2] 128 } VP8FInfo; 129 130 typedef struct { // Top/Left Contexts used for syntax-parsing 131 uint8_t nz_; // non-zero AC/DC coeffs (4bit for luma + 4bit for chroma) 132 uint8_t nz_dc_; // non-zero DC coeff (1bit) 133 } VP8MB; 134 135 // Dequantization matrices 136 typedef int quant_t[2]; // [DC / AC]. Can be 'uint16_t[2]' too (~slower). 137 typedef struct { 138 quant_t y1_mat_, y2_mat_, uv_mat_; 139 140 int uv_quant_; // U/V quantizer value 141 int dither_; // dithering amplitude (0 = off, max=255) 142 } VP8QuantMatrix; 143 144 // Data needed to reconstruct a macroblock 145 typedef struct { 146 int16_t coeffs_[384]; // 384 coeffs = (16+4+4) * 4*4 147 uint8_t is_i4x4_; // true if intra4x4 148 uint8_t imodes_[16]; // one 16x16 mode (#0) or sixteen 4x4 modes 149 uint8_t uvmode_; // chroma prediction mode 150 // bit-wise info about the content of each sub-4x4 blocks (in decoding order). 151 // Each of the 4x4 blocks for y/u/v is associated with a 2b code according to: 152 // code=0 -> no coefficient 153 // code=1 -> only DC 154 // code=2 -> first three coefficients are non-zero 155 // code=3 -> more than three coefficients are non-zero 156 // This allows to call specialized transform functions. 157 uint32_t non_zero_y_; 158 uint32_t non_zero_uv_; 159 uint8_t dither_; // local dithering strength (deduced from non_zero_*) 160 uint8_t skip_; 161 uint8_t segment_; 162 } VP8MBData; 163 164 // Persistent information needed by the parallel processing 165 typedef struct { 166 int id_; // cache row to process (in [0..2]) 167 int mb_y_; // macroblock position of the row 168 int filter_row_; // true if row-filtering is needed 169 VP8FInfo* f_info_; // filter strengths (swapped with dec->f_info_) 170 VP8MBData* mb_data_; // reconstruction data (swapped with dec->mb_data_) 171 VP8Io io_; // copy of the VP8Io to pass to put() 172 } VP8ThreadContext; 173 174 // Saved top samples, per macroblock. Fits into a cache-line. 175 typedef struct { 176 uint8_t y[16], u[8], v[8]; 177 } VP8TopSamples; 178 179 //------------------------------------------------------------------------------ 180 // VP8Decoder: the main opaque structure handed over to user 181 182 struct VP8Decoder { 183 VP8StatusCode status_; 184 int ready_; // true if ready to decode a picture with VP8Decode() 185 const char* error_msg_; // set when status_ is not OK. 186 187 // Main data source 188 VP8BitReader br_; 189 190 // headers 191 VP8FrameHeader frm_hdr_; 192 VP8PictureHeader pic_hdr_; 193 VP8FilterHeader filter_hdr_; 194 VP8SegmentHeader segment_hdr_; 195 196 // Worker 197 WebPWorker worker_; 198 int mt_method_; // multi-thread method: 0=off, 1=[parse+recon][filter] 199 // 2=[parse][recon+filter] 200 int cache_id_; // current cache row 201 int num_caches_; // number of cached rows of 16 pixels (1, 2 or 3) 202 VP8ThreadContext thread_ctx_; // Thread context 203 204 // dimension, in macroblock units. 205 int mb_w_, mb_h_; 206 207 // Macroblock to process/filter, depending on cropping and filter_type. 208 int tl_mb_x_, tl_mb_y_; // top-left MB that must be in-loop filtered 209 int br_mb_x_, br_mb_y_; // last bottom-right MB that must be decoded 210 211 // number of partitions minus one. 212 uint32_t num_parts_minus_one_; 213 // per-partition boolean decoders. 214 VP8BitReader parts_[MAX_NUM_PARTITIONS]; 215 216 // Dithering strength, deduced from decoding options 217 int dither_; // whether to use dithering or not 218 VP8Random dithering_rg_; // random generator for dithering 219 220 // dequantization (one set of DC/AC dequant factor per segment) 221 VP8QuantMatrix dqm_[NUM_MB_SEGMENTS]; 222 223 // probabilities 224 VP8Proba proba_; 225 int use_skip_proba_; 226 uint8_t skip_p_; 227 228 // Boundary data cache and persistent buffers. 229 uint8_t* intra_t_; // top intra modes values: 4 * mb_w_ 230 uint8_t intra_l_[4]; // left intra modes values 231 232 VP8TopSamples* yuv_t_; // top y/u/v samples 233 234 VP8MB* mb_info_; // contextual macroblock info (mb_w_ + 1) 235 VP8FInfo* f_info_; // filter strength info 236 uint8_t* yuv_b_; // main block for Y/U/V (size = YUV_SIZE) 237 238 uint8_t* cache_y_; // macroblock row for storing unfiltered samples 239 uint8_t* cache_u_; 240 uint8_t* cache_v_; 241 int cache_y_stride_; 242 int cache_uv_stride_; 243 244 // main memory chunk for the above data. Persistent. 245 void* mem_; 246 size_t mem_size_; 247 248 // Per macroblock non-persistent infos. 249 int mb_x_, mb_y_; // current position, in macroblock units 250 VP8MBData* mb_data_; // parsed reconstruction data 251 252 // Filtering side-info 253 int filter_type_; // 0=off, 1=simple, 2=complex 254 VP8FInfo fstrengths_[NUM_MB_SEGMENTS][2]; // precalculated per-segment/type 255 256 // Alpha 257 struct ALPHDecoder* alph_dec_; // alpha-plane decoder object 258 const uint8_t* alpha_data_; // compressed alpha data (if present) 259 size_t alpha_data_size_; 260 int is_alpha_decoded_; // true if alpha_data_ is decoded in alpha_plane_ 261 uint8_t* alpha_plane_mem_; // memory allocated for alpha_plane_ 262 uint8_t* alpha_plane_; // output. Persistent, contains the whole data. 263 const uint8_t* alpha_prev_line_; // last decoded alpha row (or NULL) 264 int alpha_dithering_; // derived from decoding options (0=off, 100=full) 265 }; 266 267 //------------------------------------------------------------------------------ 268 // internal functions. Not public. 269 270 // in vp8.c 271 int VP8SetError(VP8Decoder* const dec, 272 VP8StatusCode error, const char* const msg); 273 274 // in tree.c 275 void VP8ResetProba(VP8Proba* const proba); 276 void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec); 277 // parses one row of intra mode data in partition 0, returns !eof 278 int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec); 279 280 // in quant.c 281 void VP8ParseQuant(VP8Decoder* const dec); 282 283 // in frame.c 284 int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io); 285 // Call io->setup() and finish setting up scan parameters. 286 // After this call returns, one must always call VP8ExitCritical() with the 287 // same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK 288 // if ok, otherwise sets and returns the error status on *dec. 289 VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io); 290 // Must always be called in pair with VP8EnterCritical(). 291 // Returns false in case of error. 292 int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io); 293 // Return the multi-threading method to use (0=off), depending 294 // on options and bitstream size. Only for lossy decoding. 295 int VP8GetThreadMethod(const WebPDecoderOptions* const options, 296 const WebPHeaderStructure* const headers, 297 int width, int height); 298 // Initialize dithering post-process if needed. 299 void VP8InitDithering(const WebPDecoderOptions* const options, 300 VP8Decoder* const dec); 301 // Process the last decoded row (filtering + output). 302 int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io); 303 // To be called at the start of a new scanline, to initialize predictors. 304 void VP8InitScanline(VP8Decoder* const dec); 305 // Decode one macroblock. Returns false if there is not enough data. 306 int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br); 307 308 // in alpha.c 309 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec, 310 const VP8Io* const io, 311 int row, int num_rows); 312 313 //------------------------------------------------------------------------------ 314 315 #ifdef __cplusplus 316 } // extern "C" 317 #endif 318 319 #endif // WEBP_DEC_VP8I_DEC_H_ 320