Mercurial > SDL_sound_CoreAudio
annotate decoders/timidity/resample.c @ 532:a8492d97dd5a stable-1.0
Newer versions of Speex moved to a new include directory.
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Thu, 17 Apr 2008 17:54:55 +0000 |
| parents | f33471c47efe |
| children |
| rev | line source |
|---|---|
| 199 | 1 /* |
| 2 | |
| 3 TiMidity -- Experimental MIDI to WAVE converter | |
| 4 Copyright (C) 1995 Tuukka Toivonen <toivonen@clinet.fi> | |
| 5 | |
| 6 This program is free software; you can redistribute it and/or modify | |
| 7 it under the terms of the GNU General Public License as published by | |
| 8 the Free Software Foundation; either version 2 of the License, or | |
| 9 (at your option) any later version. | |
| 10 | |
| 11 This program is distributed in the hope that it will be useful, | |
| 12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 14 GNU General Public License for more details. | |
| 15 | |
| 16 You should have received a copy of the GNU General Public License | |
| 17 along with this program; if not, write to the Free Software | |
| 18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| 19 | |
| 20 resample.c | |
| 21 */ | |
| 22 | |
| 23 #if HAVE_CONFIG_H | |
| 24 # include <config.h> | |
| 25 #endif | |
| 26 | |
| 27 #include <math.h> | |
| 28 #include <stdio.h> | |
| 29 #include <stdlib.h> | |
| 30 | |
| 31 #include "SDL_sound.h" | |
| 32 | |
| 33 #define __SDL_SOUND_INTERNAL__ | |
| 34 #include "SDL_sound_internal.h" | |
| 35 | |
| 36 #include "timidity.h" | |
| 37 #include "options.h" | |
| 38 #include "common.h" | |
| 39 #include "instrum.h" | |
| 40 #include "playmidi.h" | |
| 41 #include "tables.h" | |
| 42 #include "resample.h" | |
| 43 | |
| 44 /*************** resampling with fixed increment *****************/ | |
| 45 | |
| 46 static sample_t *rs_plain(MidiSong *song, int v, Sint32 *countptr) | |
| 47 { | |
| 48 | |
| 49 /* Play sample until end, then free the voice. */ | |
| 50 | |
| 51 sample_t v1, v2; | |
| 52 Voice | |
| 53 *vp=&(song->voice[v]); | |
| 54 sample_t | |
| 55 *dest=song->resample_buffer, | |
| 56 *src=vp->sample->data; | |
| 57 Sint32 | |
| 58 ofs=vp->sample_offset, | |
| 59 incr=vp->sample_increment, | |
| 60 le=vp->sample->data_length, | |
| 61 count=*countptr; | |
| 62 Sint32 i; | |
| 63 | |
| 64 if (incr<0) incr = -incr; /* In case we're coming out of a bidir loop */ | |
| 65 | |
| 66 /* Precalc how many times we should go through the loop. | |
| 67 NOTE: Assumes that incr > 0 and that ofs <= le */ | |
| 68 i = (le - ofs) / incr + 1; | |
| 69 | |
| 70 if (i > count) | |
| 71 { | |
| 72 i = count; | |
| 73 count = 0; | |
| 74 } | |
| 75 else count -= i; | |
| 76 | |
| 77 while (i--) | |
| 78 { | |
| 79 v1 = src[ofs >> FRACTION_BITS]; | |
| 80 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 81 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 82 ofs += incr; | |
| 83 } | |
| 84 | |
| 85 if (ofs >= le) | |
| 86 { | |
| 87 if (ofs == le) | |
| 88 *dest++ = src[ofs >> FRACTION_BITS]; | |
| 89 vp->status=VOICE_FREE; | |
| 90 *countptr-=count+1; | |
| 91 } | |
| 92 | |
| 93 vp->sample_offset=ofs; /* Update offset */ | |
| 94 return song->resample_buffer; | |
| 95 } | |
| 96 | |
| 97 static sample_t *rs_loop(MidiSong *song, Voice *vp, Sint32 count) | |
| 98 { | |
| 99 | |
| 100 /* Play sample until end-of-loop, skip back and continue. */ | |
| 101 | |
| 102 sample_t v1, v2; | |
| 103 Sint32 | |
| 104 ofs=vp->sample_offset, | |
| 105 incr=vp->sample_increment, | |
| 106 le=vp->sample->loop_end, | |
| 107 ll=le - vp->sample->loop_start; | |
| 108 sample_t | |
| 109 *dest=song->resample_buffer, | |
| 110 *src=vp->sample->data; | |
| 111 Sint32 i; | |
| 112 | |
| 113 while (count) | |
| 114 { | |
| 115 if (ofs >= le) | |
| 116 /* NOTE: Assumes that ll > incr and that incr > 0. */ | |
| 117 ofs -= ll; | |
| 118 /* Precalc how many times we should go through the loop */ | |
| 119 i = (le - ofs) / incr + 1; | |
| 120 if (i > count) | |
| 121 { | |
| 122 i = count; | |
| 123 count = 0; | |
| 124 } | |
| 125 else count -= i; | |
| 126 while (i--) | |
| 127 { | |
| 128 v1 = src[ofs >> FRACTION_BITS]; | |
| 129 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 130 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 131 ofs += incr; | |
| 132 } | |
| 133 } | |
| 134 | |
| 135 vp->sample_offset=ofs; /* Update offset */ | |
| 136 return song->resample_buffer; | |
| 137 } | |
| 138 | |
| 139 static sample_t *rs_bidir(MidiSong *song, Voice *vp, Sint32 count) | |
| 140 { | |
| 141 sample_t v1, v2; | |
| 142 Sint32 | |
| 143 ofs=vp->sample_offset, | |
| 144 incr=vp->sample_increment, | |
| 145 le=vp->sample->loop_end, | |
| 146 ls=vp->sample->loop_start; | |
| 147 sample_t | |
| 148 *dest=song->resample_buffer, | |
| 149 *src=vp->sample->data; | |
| 150 Sint32 | |
| 151 le2 = le<<1, | |
| 152 ls2 = ls<<1, | |
| 153 i; | |
| 154 /* Play normally until inside the loop region */ | |
| 155 | |
| 156 if (ofs <= ls) | |
| 157 { | |
| 158 /* NOTE: Assumes that incr > 0, which is NOT always the case | |
| 159 when doing bidirectional looping. I have yet to see a case | |
| 160 where both ofs <= ls AND incr < 0, however. */ | |
| 161 i = (ls - ofs) / incr + 1; | |
| 162 if (i > count) | |
| 163 { | |
| 164 i = count; | |
| 165 count = 0; | |
| 166 } | |
| 167 else count -= i; | |
| 168 while (i--) | |
| 169 { | |
| 170 v1 = src[ofs >> FRACTION_BITS]; | |
| 171 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 172 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 173 ofs += incr; | |
| 174 } | |
| 175 } | |
| 176 | |
| 177 /* Then do the bidirectional looping */ | |
| 178 | |
| 179 while(count) | |
| 180 { | |
| 181 /* Precalc how many times we should go through the loop */ | |
| 182 i = ((incr > 0 ? le : ls) - ofs) / incr + 1; | |
| 183 if (i > count) | |
| 184 { | |
| 185 i = count; | |
| 186 count = 0; | |
| 187 } | |
| 188 else count -= i; | |
| 189 while (i--) | |
| 190 { | |
| 191 v1 = src[ofs >> FRACTION_BITS]; | |
| 192 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 193 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 194 ofs += incr; | |
| 195 } | |
| 196 if (ofs>=le) | |
| 197 { | |
| 198 /* fold the overshoot back in */ | |
| 199 ofs = le2 - ofs; | |
| 200 incr *= -1; | |
| 201 } | |
| 202 else if (ofs <= ls) | |
| 203 { | |
| 204 ofs = ls2 - ofs; | |
| 205 incr *= -1; | |
| 206 } | |
| 207 } | |
| 208 | |
| 209 vp->sample_increment=incr; | |
| 210 vp->sample_offset=ofs; /* Update offset */ | |
| 211 return song->resample_buffer; | |
| 212 } | |
| 213 | |
| 214 /*********************** vibrato versions ***************************/ | |
| 215 | |
| 216 /* We only need to compute one half of the vibrato sine cycle */ | |
| 217 static int vib_phase_to_inc_ptr(int phase) | |
| 218 { | |
| 219 if (phase < VIBRATO_SAMPLE_INCREMENTS/2) | |
| 220 return VIBRATO_SAMPLE_INCREMENTS/2-1-phase; | |
| 221 else if (phase >= 3*VIBRATO_SAMPLE_INCREMENTS/2) | |
| 222 return 5*VIBRATO_SAMPLE_INCREMENTS/2-1-phase; | |
| 223 else | |
| 224 return phase-VIBRATO_SAMPLE_INCREMENTS/2; | |
| 225 } | |
| 226 | |
| 227 static Sint32 update_vibrato(MidiSong *song, Voice *vp, int sign) | |
| 228 { | |
| 229 Sint32 depth; | |
| 230 int phase, pb; | |
| 231 double a; | |
| 232 | |
| 233 if (vp->vibrato_phase++ >= 2*VIBRATO_SAMPLE_INCREMENTS-1) | |
| 234 vp->vibrato_phase=0; | |
| 235 phase=vib_phase_to_inc_ptr(vp->vibrato_phase); | |
| 236 | |
| 237 if (vp->vibrato_sample_increment[phase]) | |
| 238 { | |
| 239 if (sign) | |
| 240 return -vp->vibrato_sample_increment[phase]; | |
| 241 else | |
| 242 return vp->vibrato_sample_increment[phase]; | |
| 243 } | |
| 244 | |
| 245 /* Need to compute this sample increment. */ | |
| 246 | |
| 247 depth=vp->sample->vibrato_depth<<7; | |
| 248 | |
| 249 if (vp->vibrato_sweep) | |
| 250 { | |
| 251 /* Need to update sweep */ | |
| 252 vp->vibrato_sweep_position += vp->vibrato_sweep; | |
| 253 if (vp->vibrato_sweep_position >= (1<<SWEEP_SHIFT)) | |
| 254 vp->vibrato_sweep=0; | |
| 255 else | |
| 256 { | |
| 257 /* Adjust depth */ | |
| 258 depth *= vp->vibrato_sweep_position; | |
| 259 depth >>= SWEEP_SHIFT; | |
| 260 } | |
| 261 } | |
| 262 | |
| 263 a = FSCALE(((double)(vp->sample->sample_rate) * | |
| 264 (double)(vp->frequency)) / | |
| 265 ((double)(vp->sample->root_freq) * | |
| 266 (double)(song->rate)), | |
| 267 FRACTION_BITS); | |
| 268 | |
| 269 pb=(int)((sine(vp->vibrato_phase * | |
| 270 (SINE_CYCLE_LENGTH/(2*VIBRATO_SAMPLE_INCREMENTS))) | |
| 271 * (double)(depth) * VIBRATO_AMPLITUDE_TUNING)); | |
| 272 | |
| 273 if (pb<0) | |
| 274 { | |
| 275 pb=-pb; | |
| 276 a /= bend_fine[(pb>>5) & 0xFF] * bend_coarse[pb>>13]; | |
| 277 } | |
| 278 else | |
| 279 a *= bend_fine[(pb>>5) & 0xFF] * bend_coarse[pb>>13]; | |
| 280 | |
| 281 /* If the sweep's over, we can store the newly computed sample_increment */ | |
| 282 if (!vp->vibrato_sweep) | |
| 283 vp->vibrato_sample_increment[phase]=(Sint32) a; | |
| 284 | |
| 285 if (sign) | |
| 286 a = -a; /* need to preserve the loop direction */ | |
| 287 | |
| 288 return (Sint32) a; | |
| 289 } | |
| 290 | |
| 291 static sample_t *rs_vib_plain(MidiSong *song, int v, Sint32 *countptr) | |
| 292 { | |
| 293 | |
| 294 /* Play sample until end, then free the voice. */ | |
| 295 | |
| 296 sample_t v1, v2; | |
| 297 Voice *vp=&(song->voice[v]); | |
| 298 sample_t | |
| 299 *dest=song->resample_buffer, | |
| 300 *src=vp->sample->data; | |
| 301 Sint32 | |
| 302 le=vp->sample->data_length, | |
| 303 ofs=vp->sample_offset, | |
| 304 incr=vp->sample_increment, | |
| 305 count=*countptr; | |
| 306 int | |
| 307 cc=vp->vibrato_control_counter; | |
| 308 | |
| 309 /* This has never been tested */ | |
| 310 | |
| 311 if (incr<0) incr = -incr; /* In case we're coming out of a bidir loop */ | |
| 312 | |
| 313 while (count--) | |
| 314 { | |
| 315 if (!cc--) | |
| 316 { | |
| 317 cc=vp->vibrato_control_ratio; | |
| 318 incr=update_vibrato(song, vp, 0); | |
| 319 } | |
| 320 v1 = src[ofs >> FRACTION_BITS]; | |
| 321 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 322 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 323 ofs += incr; | |
| 324 if (ofs >= le) | |
| 325 { | |
| 326 if (ofs == le) | |
| 327 *dest++ = src[ofs >> FRACTION_BITS]; | |
| 328 vp->status=VOICE_FREE; | |
| 329 *countptr-=count+1; | |
| 330 break; | |
| 331 } | |
| 332 } | |
| 333 | |
| 334 vp->vibrato_control_counter=cc; | |
| 335 vp->sample_increment=incr; | |
| 336 vp->sample_offset=ofs; /* Update offset */ | |
| 337 return song->resample_buffer; | |
| 338 } | |
| 339 | |
| 340 static sample_t *rs_vib_loop(MidiSong *song, Voice *vp, Sint32 count) | |
| 341 { | |
| 342 | |
| 343 /* Play sample until end-of-loop, skip back and continue. */ | |
| 344 | |
| 345 sample_t v1, v2; | |
| 346 Sint32 | |
| 347 ofs=vp->sample_offset, | |
| 348 incr=vp->sample_increment, | |
| 349 le=vp->sample->loop_end, | |
| 350 ll=le - vp->sample->loop_start; | |
| 351 sample_t | |
| 352 *dest=song->resample_buffer, | |
| 353 *src=vp->sample->data; | |
| 354 int | |
| 355 cc=vp->vibrato_control_counter; | |
| 356 Sint32 i; | |
| 357 int | |
| 358 vibflag=0; | |
| 359 | |
| 360 while (count) | |
| 361 { | |
| 362 /* Hopefully the loop is longer than an increment */ | |
| 363 if(ofs >= le) | |
| 364 ofs -= ll; | |
| 365 /* Precalc how many times to go through the loop, taking | |
| 366 the vibrato control ratio into account this time. */ | |
| 367 i = (le - ofs) / incr + 1; | |
| 368 if(i > count) i = count; | |
| 369 if(i > cc) | |
| 370 { | |
| 371 i = cc; | |
| 372 vibflag = 1; | |
| 373 } | |
| 374 else cc -= i; | |
| 375 count -= i; | |
| 376 while(i--) | |
| 377 { | |
| 378 v1 = src[ofs >> FRACTION_BITS]; | |
| 379 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 380 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 381 ofs += incr; | |
| 382 } | |
| 383 if(vibflag) | |
| 384 { | |
| 385 cc = vp->vibrato_control_ratio; | |
| 386 incr = update_vibrato(song, vp, 0); | |
| 387 vibflag = 0; | |
| 388 } | |
| 389 } | |
| 390 | |
| 391 vp->vibrato_control_counter=cc; | |
| 392 vp->sample_increment=incr; | |
| 393 vp->sample_offset=ofs; /* Update offset */ | |
| 394 return song->resample_buffer; | |
| 395 } | |
| 396 | |
| 397 static sample_t *rs_vib_bidir(MidiSong *song, Voice *vp, Sint32 count) | |
| 398 { | |
| 399 sample_t v1, v2; | |
| 400 Sint32 | |
| 401 ofs=vp->sample_offset, | |
| 402 incr=vp->sample_increment, | |
| 403 le=vp->sample->loop_end, | |
| 404 ls=vp->sample->loop_start; | |
| 405 sample_t | |
| 406 *dest=song->resample_buffer, | |
| 407 *src=vp->sample->data; | |
| 408 int | |
| 409 cc=vp->vibrato_control_counter; | |
| 410 Sint32 | |
| 411 le2=le<<1, | |
| 412 ls2=ls<<1, | |
| 413 i; | |
| 414 int | |
| 415 vibflag = 0; | |
| 416 | |
| 417 /* Play normally until inside the loop region */ | |
| 418 while (count && (ofs <= ls)) | |
| 419 { | |
| 420 i = (ls - ofs) / incr + 1; | |
| 421 if (i > count) i = count; | |
| 422 if (i > cc) | |
| 423 { | |
| 424 i = cc; | |
| 425 vibflag = 1; | |
| 426 } | |
| 427 else cc -= i; | |
| 428 count -= i; | |
| 429 while (i--) | |
| 430 { | |
| 431 v1 = src[ofs >> FRACTION_BITS]; | |
| 432 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 433 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 434 ofs += incr; | |
| 435 } | |
| 436 if (vibflag) | |
| 437 { | |
| 438 cc = vp->vibrato_control_ratio; | |
| 439 incr = update_vibrato(song, vp, 0); | |
| 440 vibflag = 0; | |
| 441 } | |
| 442 } | |
| 443 | |
| 444 /* Then do the bidirectional looping */ | |
| 445 | |
| 446 while (count) | |
| 447 { | |
| 448 /* Precalc how many times we should go through the loop */ | |
| 449 i = ((incr > 0 ? le : ls) - ofs) / incr + 1; | |
| 450 if(i > count) i = count; | |
| 451 if(i > cc) | |
| 452 { | |
| 453 i = cc; | |
| 454 vibflag = 1; | |
| 455 } | |
| 456 else cc -= i; | |
| 457 count -= i; | |
| 458 while (i--) | |
| 459 { | |
| 460 v1 = src[ofs >> FRACTION_BITS]; | |
| 461 v2 = src[(ofs >> FRACTION_BITS)+1]; | |
| 462 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 463 ofs += incr; | |
| 464 } | |
| 465 if (vibflag) | |
| 466 { | |
| 467 cc = vp->vibrato_control_ratio; | |
| 468 incr = update_vibrato(song, vp, (incr < 0)); | |
| 469 vibflag = 0; | |
| 470 } | |
| 471 if (ofs >= le) | |
| 472 { | |
| 473 /* fold the overshoot back in */ | |
| 474 ofs = le2 - ofs; | |
| 475 incr *= -1; | |
| 476 } | |
| 477 else if (ofs <= ls) | |
| 478 { | |
| 479 ofs = ls2 - ofs; | |
| 480 incr *= -1; | |
| 481 } | |
| 482 } | |
| 483 | |
| 484 vp->vibrato_control_counter=cc; | |
| 485 vp->sample_increment=incr; | |
| 486 vp->sample_offset=ofs; /* Update offset */ | |
| 487 return song->resample_buffer; | |
| 488 } | |
| 489 | |
| 490 sample_t *resample_voice(MidiSong *song, int v, Sint32 *countptr) | |
| 491 { | |
| 492 Sint32 ofs; | |
| 493 Uint8 modes; | |
| 494 Voice *vp=&(song->voice[v]); | |
| 495 | |
| 496 if (!(vp->sample->sample_rate)) | |
| 497 { | |
| 498 /* Pre-resampled data -- just update the offset and check if | |
| 499 we're out of data. */ | |
| 500 ofs=vp->sample_offset >> FRACTION_BITS; /* Kind of silly to use | |
| 501 FRACTION_BITS here... */ | |
| 502 if (*countptr >= (vp->sample->data_length>>FRACTION_BITS) - ofs) | |
| 503 { | |
| 504 /* Note finished. Free the voice. */ | |
| 505 vp->status = VOICE_FREE; | |
| 506 | |
| 507 /* Let the caller know how much data we had left */ | |
| 508 *countptr = (vp->sample->data_length>>FRACTION_BITS) - ofs; | |
| 509 } | |
| 510 else | |
| 511 vp->sample_offset += *countptr << FRACTION_BITS; | |
| 512 | |
| 513 return vp->sample->data+ofs; | |
| 514 } | |
| 515 | |
| 516 /* Need to resample. Use the proper function. */ | |
| 517 modes=vp->sample->modes; | |
| 518 | |
| 519 if (vp->vibrato_control_ratio) | |
| 520 { | |
| 521 if ((modes & MODES_LOOPING) && | |
| 522 ((modes & MODES_ENVELOPE) || | |
| 523 (vp->status==VOICE_ON || vp->status==VOICE_SUSTAINED))) | |
| 524 { | |
| 525 if (modes & MODES_PINGPONG) | |
| 526 return rs_vib_bidir(song, vp, *countptr); | |
| 527 else | |
| 528 return rs_vib_loop(song, vp, *countptr); | |
| 529 } | |
| 530 else | |
| 531 return rs_vib_plain(song, v, countptr); | |
| 532 } | |
| 533 else | |
| 534 { | |
| 535 if ((modes & MODES_LOOPING) && | |
| 536 ((modes & MODES_ENVELOPE) || | |
| 537 (vp->status==VOICE_ON || vp->status==VOICE_SUSTAINED))) | |
| 538 { | |
| 539 if (modes & MODES_PINGPONG) | |
| 540 return rs_bidir(song, vp, *countptr); | |
| 541 else | |
| 542 return rs_loop(song, vp, *countptr); | |
| 543 } | |
| 544 else | |
| 545 return rs_plain(song, v, countptr); | |
| 546 } | |
| 547 } | |
| 548 | |
| 549 void pre_resample(MidiSong *song, Sample *sp) | |
| 550 { | |
| 551 double a, xdiff; | |
| 552 Sint32 incr, ofs, newlen, count; | |
| 553 Sint16 *newdata, *dest, *src = (Sint16 *) sp->data; | |
| 554 Sint16 v1, v2, v3, v4, *vptr; | |
| 555 #ifdef DEBUG_CHATTER | |
| 556 static const char note_name[12][3] = | |
| 557 { | |
| 558 "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" | |
| 559 }; | |
| 560 #endif | |
| 561 | |
| 562 SNDDBG((" * pre-resampling for note %d (%s%d)\n", | |
| 563 sp->note_to_use, | |
| 564 note_name[sp->note_to_use % 12], (sp->note_to_use & 0x7F) / 12)); | |
| 565 | |
| 566 a = ((double) (sp->sample_rate) * freq_table[(int) (sp->note_to_use)]) / | |
| 567 ((double) (sp->root_freq) * song->rate); | |
| 568 newlen = (Sint32)(sp->data_length / a); | |
| 569 dest = newdata = safe_malloc(newlen >> (FRACTION_BITS - 1)); | |
| 570 | |
| 571 count = (newlen >> FRACTION_BITS) - 1; | |
| 572 ofs = incr = (sp->data_length - (1 << FRACTION_BITS)) / count; | |
| 573 | |
| 574 if (--count) | |
| 575 *dest++ = src[0]; | |
| 576 | |
| 577 /* Since we're pre-processing and this doesn't have to be done in | |
| 578 real-time, we go ahead and do the full sliding cubic interpolation. */ | |
| 579 while (--count) | |
| 580 { | |
| 581 vptr = src + (ofs >> FRACTION_BITS); | |
| 254 | 582 /* |
| 583 * Electric Fence to the rescue: Accessing *(vptr - 1) is not a | |
| 584 * good thing to do when vptr <= src. (TiMidity++ has a similar | |
| 585 * safe-guard here.) | |
| 586 */ | |
|
521
f33471c47efe
Minor correction in Timidity resampling code (Thanks, Sam!).
Ryan C. Gordon <icculus@icculus.org>
parents:
254
diff
changeset
|
587 v1 = (vptr == src) ? *vptr : *(vptr - 1); |
| 199 | 588 v2 = *vptr; |
| 589 v3 = *(vptr + 1); | |
| 590 v4 = *(vptr + 2); | |
| 591 xdiff = FSCALENEG(ofs & FRACTION_MASK, FRACTION_BITS); | |
| 592 *dest++ = (Sint16)(v2 + (xdiff / 6.0) * (-2 * v1 - 3 * v2 + 6 * v3 - v4 + | |
| 593 xdiff * (3 * (v1 - 2 * v2 + v3) + xdiff * (-v1 + 3 * (v2 - v3) + v4)))); | |
| 594 ofs += incr; | |
| 595 } | |
| 596 | |
| 597 if (ofs & FRACTION_MASK) | |
| 598 { | |
| 599 v1 = src[ofs >> FRACTION_BITS]; | |
| 600 v2 = src[(ofs >> FRACTION_BITS) + 1]; | |
| 601 *dest++ = v1 + (((v2 - v1) * (ofs & FRACTION_MASK)) >> FRACTION_BITS); | |
| 602 } | |
| 603 else | |
| 604 *dest++ = src[ofs >> FRACTION_BITS]; | |
| 605 | |
| 606 sp->data_length = newlen; | |
| 607 sp->loop_start = (Sint32)(sp->loop_start / a); | |
| 608 sp->loop_end = (Sint32)(sp->loop_end / a); | |
| 609 free(sp->data); | |
| 610 sp->data = (sample_t *) newdata; | |
| 611 sp->sample_rate = 0; | |
| 612 } |