Mercurial > SDL_sound_CoreAudio
annotate audio_convert.c @ 541:1f0a57a2483f stable-1.0
Updated.
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Thu, 17 Apr 2008 18:16:59 +0000 |
| parents | 636796aed4e2 |
| children | 9e761a594df1 |
| rev | line source |
|---|---|
| 141 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
| 3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga | |
| 4 | |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
| 20 slouken@devolution.com | |
| 21 */ | |
| 22 | |
| 23 /* | |
| 24 * This file was derived from SDL's SDL_audiocvt.c and is an attempt to | |
| 25 * address the shortcomings of it. | |
| 26 * | |
| 27 * Perhaps we can adapt some good filters from SoX? | |
| 28 */ | |
| 29 | |
| 30 #if HAVE_CONFIG_H | |
| 31 # include <config.h> | |
| 32 #endif | |
| 33 | |
|
465
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
34 #if !SOUND_USE_ALTCVT |
|
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
35 |
| 141 | 36 #include "SDL.h" |
| 37 #include "SDL_sound.h" | |
| 38 | |
| 39 #define __SDL_SOUND_INTERNAL__ | |
| 40 #include "SDL_sound_internal.h" | |
| 41 | |
| 42 /* Functions for audio drivers to perform runtime conversion of audio format */ | |
| 43 | |
| 44 | |
| 45 /* | |
| 46 * Toggle endianness. This filter is, of course, only applied to 16-bit | |
| 47 * audio data. | |
| 48 */ | |
| 49 | |
| 342 | 50 static void Sound_ConvertEndian(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 51 { |
| 52 int i; | |
| 53 Uint8 *data, tmp; | |
| 54 | |
| 55 /* SNDDBG(("Converting audio endianness\n")); */ | |
| 56 | |
| 57 data = cvt->buf; | |
| 58 | |
| 59 for (i = cvt->len_cvt / 2; i; --i) | |
| 60 { | |
| 61 tmp = data[0]; | |
| 62 data[0] = data[1]; | |
| 63 data[1] = tmp; | |
| 64 data += 2; | |
| 65 } /* for */ | |
| 66 | |
| 67 *format = (*format ^ 0x1000); | |
| 68 } /* Sound_ConvertEndian */ | |
| 69 | |
| 70 | |
| 71 /* | |
| 72 * Toggle signed/unsigned. Apparently this is done by toggling the most | |
| 73 * significant bit of each sample. | |
| 74 */ | |
| 75 | |
| 342 | 76 static void Sound_ConvertSign(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 77 { |
| 78 int i; | |
| 79 Uint8 *data; | |
| 80 | |
| 81 /* SNDDBG(("Converting audio signedness\n")); */ | |
| 82 | |
| 83 data = cvt->buf; | |
| 84 | |
| 85 /* 16-bit sound? */ | |
| 86 if ((*format & 0xFF) == 16) | |
| 87 { | |
| 88 /* Little-endian? */ | |
| 89 if ((*format & 0x1000) != 0x1000) | |
| 90 ++data; | |
| 91 | |
| 92 for (i = cvt->len_cvt / 2; i; --i) | |
| 93 { | |
| 94 *data ^= 0x80; | |
| 95 data += 2; | |
| 96 } /* for */ | |
| 97 } /* if */ | |
| 98 else | |
| 99 { | |
| 100 for (i = cvt->len_cvt; i; --i) | |
| 101 *data++ ^= 0x80; | |
| 102 } /* else */ | |
| 103 | |
| 104 *format = (*format ^ 0x8000); | |
| 105 } /* Sound_ConvertSign */ | |
| 106 | |
| 107 | |
| 108 /* | |
| 109 * Convert 16-bit to 8-bit. This is done by taking the most significant byte | |
| 110 * of each 16-bit sample. | |
| 111 */ | |
| 112 | |
| 342 | 113 static void Sound_Convert8(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 114 { |
| 115 int i; | |
| 116 Uint8 *src, *dst; | |
| 117 | |
| 118 /* SNDDBG(("Converting to 8-bit\n")); */ | |
| 119 | |
| 120 src = cvt->buf; | |
| 121 dst = cvt->buf; | |
| 122 | |
| 123 /* Little-endian? */ | |
| 124 if ((*format & 0x1000) != 0x1000) | |
| 125 ++src; | |
| 126 | |
| 127 for (i = cvt->len_cvt / 2; i; --i) | |
| 128 { | |
| 129 *dst = *src; | |
| 130 src += 2; | |
| 131 dst += 1; | |
| 132 } /* for */ | |
| 133 | |
| 134 *format = ((*format & ~0x9010) | AUDIO_U8); | |
| 135 cvt->len_cvt /= 2; | |
| 136 } /* Sound_Convert8 */ | |
| 137 | |
| 138 | |
| 139 /* Convert 8-bit to 16-bit - LSB */ | |
| 140 | |
| 342 | 141 static void Sound_Convert16LSB(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 142 { |
| 143 int i; | |
| 144 Uint8 *src, *dst; | |
| 145 | |
| 146 /* SNDDBG(("Converting to 16-bit LSB\n")); */ | |
| 147 | |
| 148 src = cvt->buf + cvt->len_cvt; | |
| 149 dst = cvt->buf + cvt->len_cvt * 2; | |
| 150 | |
| 151 for (i = cvt->len_cvt; i; --i) | |
| 152 { | |
| 153 src -= 1; | |
| 154 dst -= 2; | |
| 155 dst[1] = *src; | |
| 156 dst[0] = 0; | |
| 157 } /* for */ | |
| 158 | |
| 159 *format = ((*format & ~0x0008) | AUDIO_U16LSB); | |
| 160 cvt->len_cvt *= 2; | |
| 161 } /* Sound_Convert16LSB */ | |
| 162 | |
| 163 | |
| 164 /* Convert 8-bit to 16-bit - MSB */ | |
| 165 | |
| 342 | 166 static void Sound_Convert16MSB(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 167 { |
| 168 int i; | |
| 169 Uint8 *src, *dst; | |
| 170 | |
| 171 /* SNDDBG(("Converting to 16-bit MSB\n")); */ | |
| 172 | |
| 173 src = cvt->buf + cvt->len_cvt; | |
| 174 dst = cvt->buf + cvt->len_cvt * 2; | |
| 175 | |
| 176 for (i = cvt->len_cvt; i; --i) | |
| 177 { | |
| 178 src -= 1; | |
| 179 dst -= 2; | |
| 180 dst[0] = *src; | |
| 181 dst[1] = 0; | |
| 182 } /* for */ | |
| 183 | |
| 184 *format = ((*format & ~0x0008) | AUDIO_U16MSB); | |
| 185 cvt->len_cvt *= 2; | |
| 186 } /* Sound_Convert16MSB */ | |
| 187 | |
| 188 | |
| 189 /* Duplicate a mono channel to both stereo channels */ | |
| 190 | |
| 342 | 191 static void Sound_ConvertStereo(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 192 { |
| 193 int i; | |
| 194 | |
| 195 /* SNDDBG(("Converting to stereo\n")); */ | |
| 196 | |
| 197 /* 16-bit sound? */ | |
| 198 if ((*format & 0xFF) == 16) | |
| 199 { | |
| 200 Uint16 *src, *dst; | |
| 201 | |
| 202 src = (Uint16 *) (cvt->buf + cvt->len_cvt); | |
| 203 dst = (Uint16 *) (cvt->buf + cvt->len_cvt * 2); | |
| 204 | |
| 205 for (i = cvt->len_cvt/2; i; --i) | |
| 206 { | |
| 207 dst -= 2; | |
| 208 src -= 1; | |
| 209 dst[0] = src[0]; | |
| 210 dst[1] = src[0]; | |
| 211 } /* for */ | |
| 212 } /* if */ | |
| 213 else | |
| 214 { | |
| 215 Uint8 *src, *dst; | |
| 216 | |
| 217 src = cvt->buf + cvt->len_cvt; | |
| 218 dst = cvt->buf + cvt->len_cvt * 2; | |
| 219 | |
| 220 for (i = cvt->len_cvt; i; --i) | |
| 221 { | |
| 222 dst -= 2; | |
| 223 src -= 1; | |
| 224 dst[0] = src[0]; | |
| 225 dst[1] = src[0]; | |
| 226 } /* for */ | |
| 227 } /* else */ | |
| 228 | |
| 229 cvt->len_cvt *= 2; | |
| 230 } /* Sound_ConvertStereo */ | |
| 231 | |
| 232 | |
| 233 /* Effectively mix right and left channels into a single channel */ | |
| 234 | |
| 342 | 235 static void Sound_ConvertMono(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 236 { |
| 237 int i; | |
| 238 Sint32 sample; | |
| 239 Uint8 *u_src, *u_dst; | |
| 240 Sint8 *s_src, *s_dst; | |
| 241 | |
| 242 /* SNDDBG(("Converting to mono\n")); */ | |
| 243 | |
| 244 switch (*format) | |
| 245 { | |
| 246 case AUDIO_U8: | |
| 247 u_src = cvt->buf; | |
| 248 u_dst = cvt->buf; | |
| 249 | |
| 250 for (i = cvt->len_cvt / 2; i; --i) | |
| 251 { | |
| 252 sample = u_src[0] + u_src[1]; | |
| 253 *u_dst = (sample > 255) ? 255 : sample; | |
| 254 u_src += 2; | |
| 255 u_dst += 1; | |
| 256 } /* for */ | |
| 257 break; | |
| 258 | |
| 259 case AUDIO_S8: | |
| 260 s_src = (Sint8 *) cvt->buf; | |
| 261 s_dst = (Sint8 *) cvt->buf; | |
| 262 | |
| 263 for (i = cvt->len_cvt / 2; i; --i) | |
| 264 { | |
| 265 sample = s_src[0] + s_src[1]; | |
| 266 if (sample > 127) | |
| 267 *s_dst = 127; | |
| 268 else if (sample < -128) | |
| 269 *s_dst = -128; | |
| 270 else | |
| 271 *s_dst = sample; | |
| 272 | |
| 273 s_src += 2; | |
| 274 s_dst += 1; | |
| 275 } /* for */ | |
| 276 break; | |
| 277 | |
| 278 case AUDIO_U16MSB: | |
| 279 u_src = cvt->buf; | |
| 280 u_dst = cvt->buf; | |
| 281 | |
| 282 for (i = cvt->len_cvt / 4; i; --i) | |
| 283 { | |
| 284 sample = (Uint16) ((u_src[0] << 8) | u_src[1]) | |
| 285 + (Uint16) ((u_src[2] << 8) | u_src[3]); | |
| 286 if (sample > 65535) | |
| 287 { | |
| 288 u_dst[0] = 0xFF; | |
| 289 u_dst[1] = 0xFF; | |
| 290 } /* if */ | |
| 291 else | |
| 292 { | |
| 293 u_dst[1] = (sample & 0xFF); | |
| 294 sample >>= 8; | |
| 295 u_dst[0] = (sample & 0xFF); | |
| 296 } /* else */ | |
| 297 u_src += 4; | |
| 298 u_dst += 2; | |
| 299 } /* for */ | |
| 300 break; | |
| 301 | |
| 302 case AUDIO_U16LSB: | |
| 303 u_src = cvt->buf; | |
| 304 u_dst = cvt->buf; | |
| 305 | |
| 306 for (i = cvt->len_cvt / 4; i; --i) | |
| 307 { | |
| 308 sample = (Uint16) ((u_src[1] << 8) | u_src[0]) | |
| 309 + (Uint16) ((u_src[3] << 8) | u_src[2]); | |
| 310 if (sample > 65535) | |
| 311 { | |
| 312 u_dst[0] = 0xFF; | |
| 313 u_dst[1] = 0xFF; | |
| 314 } /* if */ | |
| 315 else | |
| 316 { | |
| 317 u_dst[0] = (sample & 0xFF); | |
| 318 sample >>= 8; | |
| 319 u_dst[1] = (sample & 0xFF); | |
| 320 } /* else */ | |
| 321 u_src += 4; | |
| 322 u_dst += 2; | |
| 323 } /* for */ | |
| 324 break; | |
| 325 | |
| 326 case AUDIO_S16MSB: | |
| 327 u_src = cvt->buf; | |
| 328 u_dst = cvt->buf; | |
| 329 | |
| 330 for (i = cvt->len_cvt / 4; i; --i) | |
| 331 { | |
| 332 sample = (Sint16) ((u_src[0] << 8) | u_src[1]) | |
| 333 + (Sint16) ((u_src[2] << 8) | u_src[3]); | |
| 334 if (sample > 32767) | |
| 335 { | |
| 336 u_dst[0] = 0x7F; | |
| 337 u_dst[1] = 0xFF; | |
| 338 } /* if */ | |
| 339 else if (sample < -32768) | |
| 340 { | |
| 341 u_dst[0] = 0x80; | |
| 342 u_dst[1] = 0x00; | |
| 343 } /* else if */ | |
| 344 else | |
| 345 { | |
| 346 u_dst[1] = (sample & 0xFF); | |
| 347 sample >>= 8; | |
| 348 u_dst[0] = (sample & 0xFF); | |
| 349 } /* else */ | |
| 350 u_src += 4; | |
| 351 u_dst += 2; | |
| 352 } /* for */ | |
| 353 break; | |
| 354 | |
| 355 case AUDIO_S16LSB: | |
| 356 u_src = cvt->buf; | |
| 357 u_dst = cvt->buf; | |
| 358 | |
| 359 for (i = cvt->len_cvt / 4; i; --i) | |
| 360 { | |
| 361 sample = (Sint16) ((u_src[1] << 8) | u_src[0]) | |
| 362 + (Sint16) ((u_src[3] << 8) | u_src[2]); | |
| 363 if (sample > 32767) | |
| 364 { | |
| 365 u_dst[1] = 0x7F; | |
| 366 u_dst[0] = 0xFF; | |
| 367 } /* if */ | |
| 368 else if (sample < -32768) | |
| 369 { | |
| 370 u_dst[1] = 0x80; | |
| 371 u_dst[0] = 0x00; | |
| 372 } /* else if */ | |
| 373 else | |
| 374 { | |
| 375 u_dst[0] = (sample & 0xFF); | |
| 376 sample >>= 8; | |
| 377 u_dst[1] = (sample & 0xFF); | |
| 378 } /* else */ | |
| 379 u_src += 4; | |
| 380 u_dst += 2; | |
| 381 } /* for */ | |
| 382 break; | |
| 383 } /* switch */ | |
| 384 | |
| 385 cvt->len_cvt /= 2; | |
| 386 } /* Sound_ConvertMono */ | |
| 387 | |
| 388 | |
| 389 /* Convert rate up by multiple of 2 */ | |
| 390 | |
| 342 | 391 static void Sound_RateMUL2(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 392 { |
| 393 int i; | |
| 394 Uint8 *src, *dst; | |
| 395 | |
| 396 /* SNDDBG(("Converting audio rate * 2\n")); */ | |
| 397 | |
| 398 src = cvt->buf + cvt->len_cvt; | |
| 399 dst = cvt->buf + cvt->len_cvt*2; | |
| 400 | |
| 401 /* 8- or 16-bit sound? */ | |
| 402 switch (*format & 0xFF) | |
| 403 { | |
| 404 case 8: | |
| 405 for (i = cvt->len_cvt; i; --i) | |
| 406 { | |
| 407 src -= 1; | |
| 408 dst -= 2; | |
| 409 dst[0] = src[0]; | |
| 410 dst[1] = src[0]; | |
| 411 } /* for */ | |
| 412 break; | |
| 413 | |
| 414 case 16: | |
| 415 for (i = cvt->len_cvt / 2; i; --i) | |
| 416 { | |
| 417 src -= 2; | |
| 418 dst -= 4; | |
| 419 dst[0] = src[0]; | |
| 420 dst[1] = src[1]; | |
| 421 dst[2] = src[0]; | |
| 422 dst[3] = src[1]; | |
| 423 } /* for */ | |
| 424 break; | |
| 425 } /* switch */ | |
| 426 | |
| 427 cvt->len_cvt *= 2; | |
| 428 } /* Sound_RateMUL2 */ | |
| 429 | |
| 430 | |
| 431 /* Convert rate down by multiple of 2 */ | |
| 432 | |
| 342 | 433 static void Sound_RateDIV2(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 434 { |
| 435 int i; | |
| 436 Uint8 *src, *dst; | |
| 437 | |
| 438 /* SNDDBG(("Converting audio rate / 2\n")); */ | |
| 439 | |
| 440 src = cvt->buf; | |
| 441 dst = cvt->buf; | |
| 442 | |
| 443 /* 8- or 16-bit sound? */ | |
| 444 switch (*format & 0xFF) | |
| 445 { | |
| 446 case 8: | |
| 447 for (i = cvt->len_cvt / 2; i; --i) | |
| 448 { | |
| 449 dst[0] = src[0]; | |
| 450 src += 2; | |
| 451 dst += 1; | |
| 452 } /* for */ | |
| 453 break; | |
| 454 | |
| 455 case 16: | |
| 456 for (i = cvt->len_cvt / 4; i; --i) | |
| 457 { | |
| 458 dst[0] = src[0]; | |
| 459 dst[1] = src[1]; | |
| 460 src += 4; | |
| 461 dst += 2; | |
| 462 } | |
| 463 break; | |
| 464 } /* switch */ | |
| 465 | |
| 466 cvt->len_cvt /= 2; | |
| 467 } /* Sound_RateDIV2 */ | |
| 468 | |
| 469 | |
| 470 /* Very slow rate conversion routine */ | |
| 471 | |
| 342 | 472 static void Sound_RateSLOW(Sound_AudioCVT *cvt, Uint16 *format) |
| 141 | 473 { |
| 474 double ipos; | |
| 475 int i, clen; | |
| 476 Uint8 *output8; | |
| 477 Uint16 *output16; | |
| 478 | |
| 479 /* SNDDBG(("Converting audio rate * %4.4f\n", 1.0/cvt->rate_incr)); */ | |
| 480 | |
| 481 clen = (int) ((double) cvt->len_cvt / cvt->rate_incr); | |
| 482 | |
| 483 if (cvt->rate_incr > 1.0) | |
| 484 { | |
| 485 /* 8- or 16-bit sound? */ | |
| 486 switch (*format & 0xFF) | |
| 487 { | |
| 488 case 8: | |
| 489 output8 = cvt->buf; | |
| 490 | |
| 491 ipos = 0.0; | |
| 492 for (i = clen; i; --i) | |
| 493 { | |
| 494 *output8 = cvt->buf[(int) ipos]; | |
| 495 ipos += cvt->rate_incr; | |
| 496 output8 += 1; | |
| 497 } /* for */ | |
| 498 break; | |
| 499 | |
| 500 case 16: | |
| 501 output16 = (Uint16 *) cvt->buf; | |
| 502 | |
| 503 clen &= ~1; | |
| 504 ipos = 0.0; | |
| 505 for (i = clen / 2; i; --i) | |
| 506 { | |
| 507 *output16 = ((Uint16 *) cvt->buf)[(int) ipos]; | |
| 508 ipos += cvt->rate_incr; | |
| 509 output16 += 1; | |
| 510 } /* for */ | |
| 511 break; | |
| 512 } /* switch */ | |
| 513 } /* if */ | |
| 514 else | |
| 515 { | |
| 516 /* 8- or 16-bit sound */ | |
| 517 switch (*format & 0xFF) | |
| 518 { | |
| 519 case 8: | |
| 520 output8 = cvt->buf + clen; | |
| 521 | |
| 522 ipos = (double) cvt->len_cvt; | |
| 523 for (i = clen; i; --i) | |
| 524 { | |
| 525 ipos -= cvt->rate_incr; | |
| 526 output8 -= 1; | |
| 527 *output8 = cvt->buf[(int) ipos]; | |
| 528 } /* for */ | |
| 529 break; | |
| 530 | |
| 531 case 16: | |
| 532 clen &= ~1; | |
| 533 output16 = (Uint16 *) (cvt->buf + clen); | |
| 534 ipos = (double) cvt->len_cvt / 2; | |
| 535 for (i = clen / 2; i; --i) | |
| 536 { | |
| 537 ipos -= cvt->rate_incr; | |
| 538 output16 -= 1; | |
| 539 *output16 = ((Uint16 *) cvt->buf)[(int) ipos]; | |
| 540 } /* for */ | |
| 541 break; | |
| 542 } /* switch */ | |
| 543 } /* else */ | |
| 544 | |
| 545 cvt->len_cvt = clen; | |
| 546 } /* Sound_RateSLOW */ | |
| 547 | |
| 548 | |
| 549 int Sound_ConvertAudio(Sound_AudioCVT *cvt) | |
| 550 { | |
| 551 Uint16 format; | |
| 552 | |
| 553 /* Make sure there's data to convert */ | |
| 554 if (cvt->buf == NULL) | |
| 555 { | |
|
387
fb519e6028e3
Changed all the Sound_SetError() calls to __Sound_SetError (or BAIL*_MACRO)
Ryan C. Gordon <icculus@icculus.org>
parents:
382
diff
changeset
|
556 __Sound_SetError("No buffer allocated for conversion"); |
| 141 | 557 return(-1); |
| 558 } /* if */ | |
| 559 | |
| 560 /* Return okay if no conversion is necessary */ | |
| 561 cvt->len_cvt = cvt->len; | |
| 562 if (cvt->filters[0] == NULL) | |
| 563 return(0); | |
| 564 | |
| 565 /* Set up the conversion and go! */ | |
| 566 format = cvt->src_format; | |
| 567 for (cvt->filter_index = 0; cvt->filters[cvt->filter_index]; | |
| 568 cvt->filter_index++) | |
| 569 { | |
| 570 cvt->filters[cvt->filter_index](cvt, &format); | |
| 571 } | |
| 572 return(0); | |
| 573 } /* Sound_ConvertAudio */ | |
| 574 | |
| 575 | |
| 576 /* | |
| 577 * Creates a set of audio filters to convert from one format to another. | |
| 578 * Returns -1 if the format conversion is not supported, or 1 if the | |
| 579 * audio filter is set up. | |
| 580 */ | |
| 581 | |
| 582 int Sound_BuildAudioCVT(Sound_AudioCVT *cvt, | |
| 583 Uint16 src_format, Uint8 src_channels, Uint32 src_rate, | |
|
382
ce998ee6194f
Sync'd with latest altcvt.
Ryan C. Gordon <icculus@icculus.org>
parents:
342
diff
changeset
|
584 Uint16 dst_format, Uint8 dst_channels, Uint32 dst_rate, |
|
ce998ee6194f
Sync'd with latest altcvt.
Ryan C. Gordon <icculus@icculus.org>
parents:
342
diff
changeset
|
585 Uint32 dst_size) |
| 141 | 586 { |
| 587 /* Start off with no conversion necessary */ | |
| 588 cvt->needed = 0; | |
| 589 cvt->filter_index = 0; | |
| 590 cvt->filters[0] = NULL; | |
| 591 cvt->len_mult = 1; | |
| 592 cvt->len_ratio = 1.0; | |
| 593 | |
| 594 /* First filter: Endian conversion from src to dst */ | |
| 595 if ((src_format & 0x1000) != (dst_format & 0x1000) && | |
| 596 ((src_format & 0xff) != 8)) | |
| 597 { | |
| 598 SNDDBG(("Adding filter: Sound_ConvertEndian\n")); | |
| 599 cvt->filters[cvt->filter_index++] = Sound_ConvertEndian; | |
| 600 } /* if */ | |
| 601 | |
| 602 /* Second filter: Sign conversion -- signed/unsigned */ | |
| 603 if ((src_format & 0x8000) != (dst_format & 0x8000)) | |
| 604 { | |
| 605 SNDDBG(("Adding filter: Sound_ConvertSign\n")); | |
| 606 cvt->filters[cvt->filter_index++] = Sound_ConvertSign; | |
| 607 } /* if */ | |
| 608 | |
| 609 /* Next filter: Convert 16 bit <--> 8 bit PCM. */ | |
| 610 if ((src_format & 0xFF) != (dst_format & 0xFF)) | |
| 611 { | |
| 612 switch (dst_format & 0x10FF) | |
| 613 { | |
| 614 case AUDIO_U8: | |
| 615 SNDDBG(("Adding filter: Sound_Convert8\n")); | |
| 616 cvt->filters[cvt->filter_index++] = Sound_Convert8; | |
| 617 cvt->len_ratio /= 2; | |
| 618 break; | |
| 619 | |
| 620 case AUDIO_U16LSB: | |
| 621 SNDDBG(("Adding filter: Sound_Convert16LSB\n")); | |
| 622 cvt->filters[cvt->filter_index++] = Sound_Convert16LSB; | |
| 623 cvt->len_mult *= 2; | |
| 624 cvt->len_ratio *= 2; | |
| 625 break; | |
| 626 | |
| 627 case AUDIO_U16MSB: | |
| 628 SNDDBG(("Adding filter: Sound_Convert16MSB\n")); | |
| 629 cvt->filters[cvt->filter_index++] = Sound_Convert16MSB; | |
| 630 cvt->len_mult *= 2; | |
| 631 cvt->len_ratio *= 2; | |
| 632 break; | |
| 633 } /* switch */ | |
| 634 } /* if */ | |
| 635 | |
| 636 /* Next filter: Mono/Stereo conversion */ | |
| 637 if (src_channels != dst_channels) | |
| 638 { | |
| 639 while ((src_channels * 2) <= dst_channels) | |
| 640 { | |
| 641 SNDDBG(("Adding filter: Sound_ConvertStereo\n")); | |
| 642 cvt->filters[cvt->filter_index++] = Sound_ConvertStereo; | |
| 643 cvt->len_mult *= 2; | |
| 644 src_channels *= 2; | |
| 645 cvt->len_ratio *= 2; | |
| 646 } /* while */ | |
| 647 | |
| 648 /* This assumes that 4 channel audio is in the format: | |
| 649 * Left {front/back} + Right {front/back} | |
| 650 * so converting to L/R stereo works properly. | |
| 651 */ | |
| 652 while (((src_channels % 2) == 0) && | |
| 653 ((src_channels / 2) >= dst_channels)) | |
| 654 { | |
| 655 SNDDBG(("Adding filter: Sound_ConvertMono\n")); | |
| 656 cvt->filters[cvt->filter_index++] = Sound_ConvertMono; | |
| 657 src_channels /= 2; | |
| 658 cvt->len_ratio /= 2; | |
| 659 } /* while */ | |
| 660 | |
| 661 if ( src_channels != dst_channels ) { | |
| 662 /* Uh oh.. */; | |
| 663 } /* if */ | |
| 664 } /* if */ | |
| 665 | |
| 666 /* Do rate conversion */ | |
| 667 cvt->rate_incr = 0.0; | |
| 668 if ((src_rate / 100) != (dst_rate / 100)) | |
| 669 { | |
| 670 Uint32 hi_rate, lo_rate; | |
| 671 int len_mult; | |
| 672 double len_ratio; | |
| 673 void (*rate_cvt)(Sound_AudioCVT *cvt, Uint16 *format); | |
| 674 | |
| 675 if (src_rate > dst_rate) | |
| 676 { | |
| 677 hi_rate = src_rate; | |
| 678 lo_rate = dst_rate; | |
| 679 SNDDBG(("Adding filter: Sound_RateDIV2\n")); | |
| 680 rate_cvt = Sound_RateDIV2; | |
| 681 len_mult = 1; | |
| 682 len_ratio = 0.5; | |
| 683 } /* if */ | |
| 684 else | |
| 685 { | |
| 686 hi_rate = dst_rate; | |
| 687 lo_rate = src_rate; | |
| 688 SNDDBG(("Adding filter: Sound_RateMUL2\n")); | |
| 689 rate_cvt = Sound_RateMUL2; | |
| 690 len_mult = 2; | |
| 691 len_ratio = 2.0; | |
| 692 } /* else */ | |
| 693 | |
| 694 /* If hi_rate = lo_rate*2^x then conversion is easy */ | |
| 695 while (((lo_rate * 2) / 100) <= (hi_rate / 100)) | |
| 696 { | |
| 697 cvt->filters[cvt->filter_index++] = rate_cvt; | |
| 698 cvt->len_mult *= len_mult; | |
| 699 lo_rate *= 2; | |
| 700 cvt->len_ratio *= len_ratio; | |
| 701 } /* while */ | |
| 702 | |
| 703 /* We may need a slow conversion here to finish up */ | |
| 704 if ((lo_rate / 100) != (hi_rate / 100)) | |
| 705 { | |
| 706 if (src_rate < dst_rate) | |
| 707 { | |
| 708 cvt->rate_incr = (double) lo_rate / hi_rate; | |
| 709 cvt->len_mult *= 2; | |
| 710 cvt->len_ratio /= cvt->rate_incr; | |
| 711 } /* if */ | |
| 712 else | |
| 713 { | |
| 714 cvt->rate_incr = (double) hi_rate / lo_rate; | |
| 715 cvt->len_ratio *= cvt->rate_incr; | |
| 716 } /* else */ | |
| 717 SNDDBG(("Adding filter: Sound_RateSLOW\n")); | |
| 718 cvt->filters[cvt->filter_index++] = Sound_RateSLOW; | |
| 719 } /* if */ | |
| 720 } /* if */ | |
| 721 | |
| 722 /* Set up the filter information */ | |
| 723 if (cvt->filter_index != 0) | |
| 724 { | |
| 725 cvt->needed = 1; | |
| 726 cvt->src_format = src_format; | |
| 727 cvt->dst_format = dst_format; | |
| 728 cvt->len = 0; | |
| 729 cvt->buf = NULL; | |
| 730 cvt->filters[cvt->filter_index] = NULL; | |
| 731 } /* if */ | |
| 732 | |
| 733 return(cvt->needed); | |
| 734 } /* Sound_BuildAudioCVT */ | |
|
465
636796aed4e2
Build/packaging fixes.
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parents:
387
diff
changeset
|
735 |
|
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
736 #endif /* !SOUND_USE_ALTCVT */ |
|
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
737 |
|
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
738 /* end of audio_convert.c ... */ |
|
636796aed4e2
Build/packaging fixes.
Ryan C. Gordon <icculus@icculus.org>
parents:
387
diff
changeset
|
739 |