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