apps/codecs/libwavpack/pack.c

   1 ////////////////////////////////////////////////////////////////////////////
   2 //                           **** WAVPACK ****                            //
   3 //                  Hybrid Lossless Wavefile Compressor                   //
   4 //              Copyright (c) 1998 - 2005 Conifer Software.               //
   5 //                          All Rights Reserved.                          //
   6 //      Distributed under the BSD Software License (see license.txt)      //
   7 ////////////////////////////////////////////////////////////////////////////
   8
   9 // pack.c
  10
  11 // This module actually handles the compression of the audio data, except for
  12 // the entropy coding which is handled by the words? modules. For efficiency,
  13 // the conversion is isolated to tight loops that handle an entire buffer.
  14
  15 #include "wavpack.h"
  16
  17 #include <string.h>
  18
  19 // This flag provides faster encoding speed at the expense of more code. The
  20 // improvement applies to 16-bit stereo lossless only.
  21
  22 //////////////////////////////// local tables ///////////////////////////////
  23
  24 // These two tables specify the characteristics of the decorrelation filters.
  25 // Each term represents one layer of the sequential filter, where positive
  26 // values indicate the relative sample involved from the same channel (1=prev),
  27 // 17 & 18 are special functions using the previous 2 samples, and negative
  28 // values indicate cross channel decorrelation (in stereo only).
  29
  30 static const signed char default_terms [] = { 18,18,2,3,-2,0 };
  31 static const signed char high_terms [] = { 18,18,2,3,-2,18,2,4,7,5,3,6,0 };
  32 static const signed char fast_terms [] = { 17,17,0 };
  33
  34 ///////////////////////////// executable code ////////////////////////////////
  35
  36 // This function initializes everything required to pack WavPack bitstreams
  37 // and must be called BEFORE any other function in this module.
  38
  39 void pack_init (WavpackContext *wpc)
  40 {
  41     WavpackStream *wps = &wpc->stream;
  42     uint32_t flags = wps->wphdr.flags;
  43     struct decorr_pass *dpp;
  44     const signed char *term_string;
  45     int ti;
  46
  47     wps->sample_index = 0;
  48     CLEAR (wps->decorr_passes);
  49
  50     if (wpc->config.flags & CONFIG_HIGH_FLAG)
  51         term_string = high_terms;
  52     else if (wpc->config.flags & CONFIG_FAST_FLAG)
  53         term_string = fast_terms;
  54     else
  55         term_string = default_terms;
  56
  57     for (dpp = wps->decorr_passes, ti = 0; term_string [ti]; ti++)
  58         if (term_string [ti] >= 0 || (flags & CROSS_DECORR)) {
  59             dpp->term = term_string [ti];
  60             dpp++->delta = 2;
  61         }
  62         else if (!(flags & MONO_FLAG)) {
  63             dpp->term = -3;
  64             dpp++->delta = 2;
  65         }
  66
  67     wps->num_terms = dpp - wps->decorr_passes;
  68     init_words (wps);
  69 }
  70
  71 // Allocate room for and copy the decorrelation terms from the decorr_passes
  72 // array into the specified metadata structure. Both the actual term id and
  73 // the delta are packed into single characters.
  74
  75 static void write_decorr_terms (WavpackStream *wps, WavpackMetadata *wpmd)
  76 {
  77     int tcount = wps->num_terms;
  78     struct decorr_pass *dpp;
  79     char *byteptr;
  80
  81     byteptr = wpmd->data = wpmd->temp_data;
  82     wpmd->id = ID_DECORR_TERMS;
  83
  84     for (dpp = wps->decorr_passes; tcount--; ++dpp)
  85         *byteptr++ = ((dpp->term + 5) & 0x1f) | ((dpp->delta << 5) & 0xe0);
  86
  87     wpmd->byte_length = byteptr - (char *) wpmd->data;
  88 }
  89
  90 // Allocate room for and copy the decorrelation term weights from the
  91 // decorr_passes array into the specified metadata structure. The weights
  92 // range +/-1024, but are rounded and truncated to fit in signed chars for
  93 // metadata storage. Weights are separate for the two channels
  94
  95 static void write_decorr_weights (WavpackStream *wps, WavpackMetadata *wpmd)
  96 {
  97     int tcount = wps->num_terms;
  98     struct decorr_pass *dpp;
  99     signed char *byteptr;
 100
 101     byteptr = wpmd->data = wpmd->temp_data;
 102     wpmd->id = ID_DECORR_WEIGHTS;
 103
 104     for (dpp = wps->decorr_passes; tcount--; ++dpp) {
 105         dpp->weight_A = restore_weight (*byteptr++ = store_weight (dpp->weight_A));
 106
 107         if (!(wps->wphdr.flags & MONO_FLAG))
 108             dpp->weight_B = restore_weight (*byteptr++ = store_weight (dpp->weight_B));
 109     }
 110
 111     wpmd->byte_length = byteptr - (signed char *) wpmd->data;
 112 }
 113
 114 // Allocate room for and copy the decorrelation samples from the decorr_passes
 115 // array into the specified metadata structure. The samples are signed 32-bit
 116 // values, but are converted to signed log2 values for storage in metadata.
 117 // Values are stored for both channels and are specified from the first term
 118 // with unspecified samples set to zero. The number of samples stored varies
 119 // with the actual term value, so those must obviously be specified before
 120 // these in the metadata list. Any number of terms can have their samples
 121 // specified from no terms to all the terms, however I have found that
 122 // sending more than the first term's samples is a waste. The "wcount"
 123 // variable can be set to the number of terms to have their samples stored.
 124
 125 static void write_decorr_samples (WavpackStream *wps, WavpackMetadata *wpmd)
 126 {
 127     int tcount = wps->num_terms, wcount = 1, temp;
 128     struct decorr_pass *dpp;
 129     uchar *byteptr;
 130
 131     byteptr = wpmd->data = wpmd->temp_data;
 132     wpmd->id = ID_DECORR_SAMPLES;
 133
 134     for (dpp = wps->decorr_passes; tcount--; ++dpp)
 135         if (wcount) {
 136             if (dpp->term > MAX_TERM) {
 137                 dpp->samples_A [0] = exp2s (temp = log2s (dpp->samples_A [0]));
 138                 *byteptr++ = temp;
 139                 *byteptr++ = temp >> 8;
 140                 dpp->samples_A [1] = exp2s (temp = log2s (dpp->samples_A [1]));
 141                 *byteptr++ = temp;
 142                 *byteptr++ = temp >> 8;
 143
 144                 if (!(wps->wphdr.flags & MONO_FLAG)) {
 145                     dpp->samples_B [0] = exp2s (temp = log2s (dpp->samples_B [0]));
 146                     *byteptr++ = temp;
 147                     *byteptr++ = temp >> 8;
 148                     dpp->samples_B [1] = exp2s (temp = log2s (dpp->samples_B [1]));
 149                     *byteptr++ = temp;
 150                     *byteptr++ = temp >> 8;
 151                 }
 152             }
 153             else if (dpp->term < 0) {
 154                 dpp->samples_A [0] = exp2s (temp = log2s (dpp->samples_A [0]));
 155                 *byteptr++ = temp;
 156                 *byteptr++ = temp >> 8;
 157                 dpp->samples_B [0] = exp2s (temp = log2s (dpp->samples_B [0]));
 158                 *byteptr++ = temp;
 159                 *byteptr++ = temp >> 8;
 160             }
 161             else {
 162                 int m = 0, cnt = dpp->term;
 163
 164                 while (cnt--) {
 165                     dpp->samples_A [m] = exp2s (temp = log2s (dpp->samples_A [m]));
 166                     *byteptr++ = temp;
 167                     *byteptr++ = temp >> 8;
 168
 169                     if (!(wps->wphdr.flags & MONO_FLAG)) {
 170                         dpp->samples_B [m] = exp2s (temp = log2s (dpp->samples_B [m]));
 171                         *byteptr++ = temp;
 172                         *byteptr++ = temp >> 8;
 173                     }
 174
 175                     m++;
 176                 }
 177             }
 178
 179             wcount--;
 180         }
 181         else {
 182             CLEAR (dpp->samples_A);
 183             CLEAR (dpp->samples_B);
 184         }
 185
 186     wpmd->byte_length = byteptr - (uchar *) wpmd->data;
 187 }
 188
 189 // Allocate room for and copy the configuration information into the specified
 190 // metadata structure. Currently, we just store the upper 3 bytes of
 191 // config.flags and only in the first block of audio data. Note that this is
 192 // for informational purposes not required for playback or decoding (like
 193 // whether high or fast mode was specified).
 194
 195 static void write_config_info (WavpackContext *wpc, WavpackMetadata *wpmd)
 196 {
 197     char *byteptr;
 198
 199     byteptr = wpmd->data = wpmd->temp_data;
 200     wpmd->id = ID_CONFIG_BLOCK;
 201     *byteptr++ = (char) (wpc->config.flags >> 8);
 202     *byteptr++ = (char) (wpc->config.flags >> 16);
 203     *byteptr++ = (char) (wpc->config.flags >> 24);
 204     wpmd->byte_length = byteptr - (char *) wpmd->data;
 205 }
 206
 207 // Pack an entire block of samples (either mono or stereo) into a completed
 208 // WavPack block. It is assumed that there is sufficient space for the
 209 // completed block at "wps->blockbuff" and that "wps->blockend" points to the
 210 // end of the available space. A return value of FALSE indicates an error.
 211 // Any unsent metadata is transmitted first, then required metadata for this
 212 // block is sent, and finally the compressed integer data is sent. If a "wpx"
 213 // stream is required for floating point data or large integer data, then this
 214 // must be handled outside this function. To find out how much data was written
 215 // the caller must look at the ckSize field of the written WavpackHeader, NOT
 216 // the one in the WavpackStream.
 217
 218 int pack_start_block (WavpackContext *wpc)
 219 {
 220     WavpackStream *wps = &wpc->stream;
 221     WavpackMetadata wpmd;
 222
 223     memcpy (wps->blockbuff, &wps->wphdr, sizeof (WavpackHeader));
 224
 225     ((WavpackHeader *) wps->blockbuff)->ckSize = sizeof (WavpackHeader) - 8;
 226     ((WavpackHeader *) wps->blockbuff)->block_index = wps->sample_index;
 227     ((WavpackHeader *) wps->blockbuff)->block_samples = 0;
 228     ((WavpackHeader *) wps->blockbuff)->crc = 0xffffffff;
 229
 230     if (wpc->wrapper_bytes) {
 231         wpmd.id = ID_RIFF_HEADER;
 232         wpmd.byte_length = wpc->wrapper_bytes;
 233         wpmd.data = wpc->wrapper_data;
 234         copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 235         free_metadata (&wpmd);
 236         wpc->wrapper_data = NULL;
 237         wpc->wrapper_bytes = 0;
 238     }
 239
 240     write_decorr_terms (wps, &wpmd);
 241     copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 242     free_metadata (&wpmd);
 243
 244     write_decorr_weights (wps, &wpmd);
 245     copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 246     free_metadata (&wpmd);
 247
 248     write_decorr_samples (wps, &wpmd);
 249     copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 250     free_metadata (&wpmd);
 251
 252     write_entropy_vars (wps, &wpmd);
 253     copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 254     free_metadata (&wpmd);
 255
 256     if ((wps->wphdr.flags & INITIAL_BLOCK) && !wps->sample_index) {
 257         write_config_info (wpc, &wpmd);
 258         copy_metadata (&wpmd, wps->blockbuff, wps->blockend);
 259         free_metadata (&wpmd);
 260     }
 261
 262     bs_open_write (&wps->wvbits, wps->blockbuff + ((WavpackHeader *) wps->blockbuff)->ckSize + 12, wps->blockend);
 263
 264     return TRUE;
 265 }
 266
 267 static void decorr_stereo_pass (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr, int m);
 268 static void decorr_stereo_pass_18 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr);
 269 static void decorr_stereo_pass_17 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr);
 270 static void decorr_stereo_pass_m2 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr);
 271
 272 int pack_samples (WavpackContext *wpc, int32_t *buffer, uint32_t sample_count)
 273 {
 274     WavpackStream *wps = &wpc->stream;
 275     uint32_t flags = wps->wphdr.flags;
 276     struct decorr_pass *dpp;
 277     int32_t *bptr, *eptr;
 278     int tcount, m;
 279     uint32_t crc;
 280
 281     if (!sample_count)
 282         return TRUE;
 283
 284     eptr = buffer + sample_count * ((flags & MONO_FLAG) ? 1 : 2);
 285     m = ((WavpackHeader *) wps->blockbuff)->block_samples & (MAX_TERM - 1);
 286     crc = ((WavpackHeader *) wps->blockbuff)->crc;
 287
 288     /////////////////////// handle lossless mono mode /////////////////////////
 289
 290     if (!(flags & HYBRID_FLAG) && (flags & MONO_FLAG))
 291         for (bptr = buffer; bptr < eptr;) {
 292             int32_t code;
 293
 294             crc = crc * 3 + (code = *bptr);
 295
 296             for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++) {
 297                 int32_t sam;
 298
 299                 if (dpp->term > MAX_TERM) {
 300                     if (dpp->term & 1)
 301                         sam = 2 * dpp->samples_A [0] - dpp->samples_A [1];
 302                     else
 303                         sam = (3 * dpp->samples_A [0] - dpp->samples_A [1]) >> 1;
 304
 305                     dpp->samples_A [1] = dpp->samples_A [0];
 306                     dpp->samples_A [0] = code;
 307                 }
 308                 else {
 309                     sam = dpp->samples_A [m];
 310                     dpp->samples_A [(m + dpp->term) & (MAX_TERM - 1)] = code;
 311                 }
 312
 313                 code -= apply_weight_i (dpp->weight_A, sam);
 314                 update_weight (dpp->weight_A, 2, sam, code);
 315             }
 316
 317             m = (m + 1) & (MAX_TERM - 1);
 318             *bptr++ = code;
 319         }
 320
 321     //////////////////// handle the lossless stereo mode //////////////////////
 322
 323     else if (!(flags & HYBRID_FLAG) && !(flags & MONO_FLAG)) {
 324         if (flags & JOINT_STEREO)
 325             for (bptr = buffer; bptr < eptr; bptr += 2) {
 326                 crc = crc * 9 + (bptr [0] * 3) + bptr [1];
 327                 bptr [1] += ((bptr [0] -= bptr [1]) >> 1);
 328             }
 329         else
 330             for (bptr = buffer; bptr < eptr; bptr += 2)
 331                 crc = crc * 9 + (bptr [0] * 3) + bptr [1];
 332
 333         for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount-- ; dpp++) {
 334             if (dpp->term == 17)
 335                 decorr_stereo_pass_17 (dpp, buffer, eptr);
 336             else if (dpp->term == 18)
 337                 decorr_stereo_pass_18 (dpp, buffer, eptr);
 338             else if (dpp->term >= 1 && dpp->term <= 7)
 339                 decorr_stereo_pass (dpp, buffer, eptr, m);
 340             else if (dpp->term == -2)
 341                 decorr_stereo_pass_m2 (dpp, buffer, eptr);
 342         }
 343     }
 344
 345     send_words (buffer, sample_count, flags, &wps->w, &wps->wvbits);
 346     ((WavpackHeader *) wps->blockbuff)->crc = crc;
 347     ((WavpackHeader *) wps->blockbuff)->block_samples += sample_count;
 348     wps->sample_index += sample_count;
 349
 350     return TRUE;
 351 }
 352
 353 static void decorr_stereo_pass (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr, int m)
 354 {
 355     int k = (m + dpp->term) & (MAX_TERM - 1);
 356     int32_t sam;
 357
 358     while (bptr < eptr) {
 359         dpp->samples_A [k] = bptr [0];
 360         bptr [0] -= apply_weight_i (dpp->weight_A, (sam = dpp->samples_A [m]));
 361         update_weight (dpp->weight_A, 2, sam, bptr [0]);
 362         bptr++;
 363         dpp->samples_B [k] = bptr [0];
 364         bptr [0] -= apply_weight_i (dpp->weight_B, (sam = dpp->samples_B [m]));
 365         update_weight (dpp->weight_B, 2, sam, bptr [0]);
 366         bptr++;
 367         m = (m + 1) & (MAX_TERM - 1);
 368         k = (k + 1) & (MAX_TERM - 1);
 369     }
 370 }
 371
 372 static void decorr_stereo_pass_18 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr)
 373 {
 374     int32_t sam;
 375
 376     while (bptr < eptr) {
 377         sam = (3 * dpp->samples_A [0] - dpp->samples_A [1]) >> 1;
 378         dpp->samples_A [1] = dpp->samples_A [0];
 379         dpp->samples_A [0] = bptr [0];
 380         bptr [0] -= apply_weight_i (dpp->weight_A, sam);
 381         update_weight (dpp->weight_A, 2, sam, bptr [0]);
 382         bptr++;
 383         sam = (3 * dpp->samples_B [0] - dpp->samples_B [1]) >> 1;
 384         dpp->samples_B [1] = dpp->samples_B [0];
 385         dpp->samples_B [0] = bptr [0];
 386         bptr [0] -= apply_weight_i (dpp->weight_B, sam);
 387         update_weight (dpp->weight_B, 2, sam, bptr [0]);
 388         bptr++;
 389     }
 390 }
 391
 392 static void decorr_stereo_pass_m2 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr)
 393 {
 394     int32_t sam_A, sam_B;
 395
 396     for (; bptr < eptr; bptr += 2) {
 397         sam_A = bptr [1];
 398         sam_B = dpp->samples_B [0];
 399         dpp->samples_B [0] = bptr [0];
 400         bptr [0] -= apply_weight_i (dpp->weight_A, sam_A);
 401         update_weight_clip (dpp->weight_A, 2, sam_A, bptr [0]);
 402         bptr [1] -= apply_weight_i (dpp->weight_B, sam_B);
 403         update_weight_clip (dpp->weight_B, 2, sam_B, bptr [1]);
 404     }
 405 }
 406
 407 static void decorr_stereo_pass_17 (struct decorr_pass *dpp, int32_t *bptr, int32_t *eptr)
 408 {
 409     int32_t sam;
 410
 411     while (bptr < eptr) {
 412         sam = 2 * dpp->samples_A [0] - dpp->samples_A [1];
 413         dpp->samples_A [1] = dpp->samples_A [0];
 414         dpp->samples_A [0] = bptr [0];
 415         bptr [0] -= apply_weight_i (dpp->weight_A, sam);
 416         update_weight (dpp->weight_A, 2, sam, bptr [0]);
 417         bptr++;
 418         sam = 2 * dpp->samples_B [0] - dpp->samples_B [1];
 419         dpp->samples_B [1] = dpp->samples_B [0];
 420         dpp->samples_B [0] = bptr [0];
 421         bptr [0] -= apply_weight_i (dpp->weight_B, sam);
 422         update_weight (dpp->weight_B, 2, sam, bptr [0]);
 423         bptr++;
 424     }
 425 }
 426
 427 int pack_finish_block (WavpackContext *wpc)
 428 {
 429     WavpackStream *wps = &wpc->stream;
 430     struct decorr_pass *dpp;
 431     uint32_t data_count;
 432     int tcount, m;
 433
 434     m = ((WavpackHeader *) wps->blockbuff)->block_samples & (MAX_TERM - 1);
 435
 436     if (m)
 437         for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++)
 438             if (dpp->term > 0 && dpp->term <= MAX_TERM) {
 439                 int32_t temp_A [MAX_TERM], temp_B [MAX_TERM];
 440                 int k;
 441
 442                 memcpy (temp_A, dpp->samples_A, sizeof (dpp->samples_A));
 443                 memcpy (temp_B, dpp->samples_B, sizeof (dpp->samples_B));
 444
 445                 for (k = 0; k < MAX_TERM; k++) {
 446                     dpp->samples_A [k] = temp_A [m];
 447                     dpp->samples_B [k] = temp_B [m];
 448                     m = (m + 1) & (MAX_TERM - 1);
 449                 }
 450             }
 451
 452     flush_word (&wps->w, &wps->wvbits);
 453     data_count = bs_close_write (&wps->wvbits);
 454
 455     if (data_count) {
 456         if (data_count != (uint32_t) -1) {
 457             uchar *cptr = wps->blockbuff + ((WavpackHeader *) wps->blockbuff)->ckSize + 8;
 458
 459             *cptr++ = ID_WV_BITSTREAM | ID_LARGE;
 460             *cptr++ = data_count >> 1;
 461             *cptr++ = data_count >> 9;
 462             *cptr++ = data_count >> 17;
 463             ((WavpackHeader *) wps->blockbuff)->ckSize += data_count + 4;
 464         }
 465         else
 466             return FALSE;
 467     }
 468
 469     return TRUE;
 470 }