This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_audio.c
1245 lines (1088 loc) · 35.9 KB
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2009 Sam Lantinga
4
5
This library is free software; you can redistribute it and/or
6
modify it under the terms of the GNU Lesser General Public
7
License as published by the Free Software Foundation; either
8
version 2.1 of the License, or (at your option) any later version.
9
10
11
12
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13
Lesser General Public License for more details.
14
15
16
17
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19
Sam Lantinga
20
slouken@libsdl.org
21
*/
22
#include "SDL_config.h"
23
24
25
26
/* Allow access to a raw mixing buffer */
#include "SDL.h"
27
#include "SDL_audio.h"
28
29
30
31
#include "SDL_audio_c.h"
#include "SDL_audiomem.h"
#include "SDL_sysaudio.h"
32
#define _THIS SDL_AudioDevice *this
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
static SDL_AudioDriver current_audio;
static SDL_AudioDevice *open_devices[16];
/* !!! FIXME: These are wordy and unlocalized... */
#define DEFAULT_OUTPUT_DEVNAME "System audio output device"
#define DEFAULT_INPUT_DEVNAME "System audio capture device"
/*
* Not all of these will be compiled and linked in, but it's convenient
* to have a complete list here and saves yet-another block of #ifdefs...
* Please see bootstrap[], below, for the actual #ifdef mess.
*/
extern AudioBootStrap BSD_AUDIO_bootstrap;
extern AudioBootStrap DSP_bootstrap;
extern AudioBootStrap DMA_bootstrap;
extern AudioBootStrap ALSA_bootstrap;
51
extern AudioBootStrap PULSEAUDIO_bootstrap;
52
53
54
55
56
57
58
extern AudioBootStrap QNXNTOAUDIO_bootstrap;
extern AudioBootStrap SUNAUDIO_bootstrap;
extern AudioBootStrap DMEDIA_bootstrap;
extern AudioBootStrap ARTS_bootstrap;
extern AudioBootStrap ESD_bootstrap;
extern AudioBootStrap NAS_bootstrap;
extern AudioBootStrap DSOUND_bootstrap;
59
extern AudioBootStrap WINWAVEOUT_bootstrap;
60
61
62
extern AudioBootStrap PAUDIO_bootstrap;
extern AudioBootStrap BEOSAUDIO_bootstrap;
extern AudioBootStrap COREAUDIO_bootstrap;
63
extern AudioBootStrap COREAUDIOIPHONE_bootstrap;
64
65
66
67
68
69
70
71
72
73
74
extern AudioBootStrap SNDMGR_bootstrap;
extern AudioBootStrap MINTAUDIO_GSXB_bootstrap;
extern AudioBootStrap MINTAUDIO_MCSN_bootstrap;
extern AudioBootStrap MINTAUDIO_STFA_bootstrap;
extern AudioBootStrap MINTAUDIO_XBIOS_bootstrap;
extern AudioBootStrap MINTAUDIO_DMA8_bootstrap;
extern AudioBootStrap DISKAUD_bootstrap;
extern AudioBootStrap DUMMYAUD_bootstrap;
extern AudioBootStrap DCAUD_bootstrap;
extern AudioBootStrap MMEAUDIO_bootstrap;
extern AudioBootStrap DART_bootstrap;
75
extern AudioBootStrap NDSAUD_bootstrap;
76
extern AudioBootStrap FUSIONSOUND_bootstrap;
77
78
79
80
/* Available audio drivers */
static AudioBootStrap *bootstrap[] = {
81
#if SDL_AUDIO_DRIVER_BSD
82
&BSD_AUDIO_bootstrap,
83
#endif
84
85
#if SDL_AUDIO_DRIVER_PULSEAUDIO
&PULSEAUDIO_bootstrap,
86
#endif
87
#if SDL_AUDIO_DRIVER_ALSA
88
&ALSA_bootstrap,
89
#endif
90
91
92
#if SDL_AUDIO_DRIVER_OSS
&DSP_bootstrap,
&DMA_bootstrap,
93
#endif
94
#if SDL_AUDIO_DRIVER_QNXNTO
95
&QNXNTOAUDIO_bootstrap,
96
#endif
97
#if SDL_AUDIO_DRIVER_SUNAUDIO
98
&SUNAUDIO_bootstrap,
99
#endif
100
#if SDL_AUDIO_DRIVER_DMEDIA
101
&DMEDIA_bootstrap,
102
#endif
103
#if SDL_AUDIO_DRIVER_ARTS
104
&ARTS_bootstrap,
105
#endif
106
#if SDL_AUDIO_DRIVER_ESD
107
&ESD_bootstrap,
108
#endif
109
#if SDL_AUDIO_DRIVER_NAS
110
&NAS_bootstrap,
111
#endif
112
#if SDL_AUDIO_DRIVER_DSOUND
113
&DSOUND_bootstrap,
114
#endif
115
116
#if SDL_AUDIO_DRIVER_WINWAVEOUT
&WINWAVEOUT_bootstrap,
117
#endif
118
119
#if SDL_AUDIO_DRIVER_PAUDIO
&PAUDIO_bootstrap,
120
#endif
121
122
#if SDL_AUDIO_DRIVER_BEOSAUDIO
&BEOSAUDIO_bootstrap,
123
#endif
124
#if SDL_AUDIO_DRIVER_COREAUDIO
125
&COREAUDIO_bootstrap,
126
#endif
127
128
129
#if SDL_AUDIO_DRIVER_COREAUDIOIPHONE
&COREAUDIOIPHONE_bootstrap,
#endif
130
#if SDL_AUDIO_DRIVER_SNDMGR
131
&SNDMGR_bootstrap,
132
#endif
133
#if SDL_AUDIO_DRIVER_MINT
134
135
136
137
138
&MINTAUDIO_GSXB_bootstrap,
&MINTAUDIO_MCSN_bootstrap,
&MINTAUDIO_STFA_bootstrap,
&MINTAUDIO_XBIOS_bootstrap,
&MINTAUDIO_DMA8_bootstrap,
139
#endif
140
#if SDL_AUDIO_DRIVER_DISK
141
&DISKAUD_bootstrap,
142
#endif
143
#if SDL_AUDIO_DRIVER_DUMMY
144
&DUMMYAUD_bootstrap,
145
#endif
146
#if SDL_AUDIO_DRIVER_DC
147
&DCAUD_bootstrap,
148
#endif
149
#if SDL_AUDIO_DRIVER_MMEAUDIO
150
&MMEAUDIO_bootstrap,
151
152
#endif
#if SDL_AUDIO_DRIVER_DART
153
&DART_bootstrap,
154
155
156
#endif
#if SDL_AUDIO_DRIVER_NDS
&NDSAUD_bootstrap,
157
158
159
#endif
#if SDL_AUDIO_DRIVER_FUSIONSOUND
&FUSIONSOUND_bootstrap,
160
#endif
161
NULL
162
163
};
164
165
static SDL_AudioDevice *
get_audio_device(SDL_AudioDeviceID id)
166
167
{
id--;
168
if ((id >= SDL_arraysize(open_devices)) || (open_devices[id] == NULL)) {
169
170
171
172
173
174
175
176
177
SDL_SetError("Invalid audio device ID");
return NULL;
}
return open_devices[id];
}
/* stubs for audio drivers that don't need a specific entry point... */
178
179
180
181
182
static int
SDL_AudioDetectDevices_Default(int iscapture)
{
return -1;
}
183
184
185
186
187
static void
SDL_AudioThreadInit_Default(_THIS)
{ /* no-op. */
}
188
189
190
191
192
static void
SDL_AudioWaitDevice_Default(_THIS)
{ /* no-op. */
}
193
194
195
196
197
static void
SDL_AudioPlayDevice_Default(_THIS)
{ /* no-op. */
}
198
199
200
201
202
203
static Uint8 *
SDL_AudioGetDeviceBuf_Default(_THIS)
{
return NULL;
}
204
205
206
207
208
static void
SDL_AudioWaitDone_Default(_THIS)
{ /* no-op. */
}
209
210
211
212
213
static void
SDL_AudioCloseDevice_Default(_THIS)
{ /* no-op. */
}
214
215
216
217
218
static void
SDL_AudioDeinitialize_Default(void)
{ /* no-op. */
}
219
220
221
222
223
224
225
static int
SDL_AudioOpenDevice_Default(_THIS, const char *devname, int iscapture)
{
return 0;
}
226
227
static const char *
SDL_AudioGetDeviceName_Default(int index, int iscapture)
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
{
SDL_SetError("No such device");
return NULL;
}
static void
SDL_AudioLockDevice_Default(SDL_AudioDevice * device)
{
if (device->thread && (SDL_ThreadID() == device->threadid)) {
return;
}
SDL_mutexP(device->mixer_lock);
}
static void
SDL_AudioUnlockDevice_Default(SDL_AudioDevice * device)
{
if (device->thread && (SDL_ThreadID() == device->threadid)) {
return;
}
SDL_mutexV(device->mixer_lock);
}
252
253
static void
finalize_audio_entry_points(void)
254
255
256
257
258
259
{
/*
* Fill in stub functions for unused driver entry points. This lets us
* blindly call them without having to check for validity first.
*/
260
#define FILL_STUB(x) \
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
if (current_audio.impl.x == NULL) { \
current_audio.impl.x = SDL_Audio##x##_Default; \
}
FILL_STUB(DetectDevices);
FILL_STUB(GetDeviceName);
FILL_STUB(OpenDevice);
FILL_STUB(ThreadInit);
FILL_STUB(WaitDevice);
FILL_STUB(PlayDevice);
FILL_STUB(GetDeviceBuf);
FILL_STUB(WaitDone);
FILL_STUB(CloseDevice);
FILL_STUB(LockDevice);
FILL_STUB(UnlockDevice);
FILL_STUB(Deinitialize);
276
#undef FILL_STUB
277
}
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
/* Streaming functions (for when the input and output buffer sizes are different) */
/* Write [length] bytes from buf into the streamer */
void
SDL_StreamWrite(SDL_AudioStreamer * stream, Uint8 * buf, int length)
{
int i;
for (i = 0; i < length; ++i) {
stream->buffer[stream->write_pos] = buf[i];
++stream->write_pos;
}
}
/* Read [length] bytes out of the streamer into buf */
void
SDL_StreamRead(SDL_AudioStreamer * stream, Uint8 * buf, int length)
{
int i;
for (i = 0; i < length; ++i) {
buf[i] = stream->buffer[stream->read_pos];
++stream->read_pos;
}
}
int
SDL_StreamLength(SDL_AudioStreamer * stream)
{
return (stream->write_pos - stream->read_pos) % stream->max_len;
}
/* Initialize the stream by allocating the buffer and setting the read/write heads to the beginning */
int
SDL_StreamInit(SDL_AudioStreamer * stream, int max_len, Uint8 silence)
{
/* First try to allocate the buffer */
315
stream->buffer = (Uint8 *) SDL_malloc(max_len);
316
317
318
319
320
321
322
323
324
if (stream->buffer == NULL) {
return -1;
}
stream->max_len = max_len;
stream->read_pos = 0;
stream->write_pos = 0;
/* Zero out the buffer */
325
326
327
SDL_memset(stream->buffer, silence, max_len);
return 0;
328
329
330
331
332
333
334
}
/* Deinitialize the stream simply by freeing the buffer */
void
SDL_StreamDeinit(SDL_AudioStreamer * stream)
{
if (stream->buffer != NULL) {
335
SDL_free(stream->buffer);
336
337
338
}
}
339
340
/* The general mixing thread function */
341
int SDLCALL
342
SDL_RunAudio(void *devicep)
343
{
344
SDL_AudioDevice *device = (SDL_AudioDevice *) devicep;
345
346
347
348
349
Uint8 *stream;
int stream_len;
void *udata;
void (SDLCALL * fill) (void *userdata, Uint8 * stream, int len);
int silence;
350
351
352
353
354
int stream_max_len;
/* For streaming when the buffer sizes don't match up */
Uint8 *istream;
int istream_len;
355
356
/* Perform any thread setup */
357
358
device->threadid = SDL_ThreadID();
current_audio.impl.ThreadInit(device);
359
360
/* Set up the mixing function */
361
362
fill = device->spec.callback;
udata = device->spec.userdata;
363
364
365
366
/* By default do not stream */
device->use_streamer = 0;
367
368
if (device->convert.needed) {
if (device->convert.src_format == AUDIO_U8) {
369
370
371
372
silence = 0x80;
} else {
silence = 0;
}
373
374
#if 0 /* !!! FIXME: I took len_div out of the structure. Use rate_incr instead? */
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
/* If the result of the conversion alters the length, i.e. resampling is being used, use the streamer */
if (device->convert.len_mult != 1 || device->convert.len_div != 1) {
/* The streamer's maximum length should be twice whichever is larger: spec.size or len_cvt */
stream_max_len = 2 * device->spec.size;
if (device->convert.len_mult > device->convert.len_div) {
stream_max_len *= device->convert.len_mult;
stream_max_len /= device->convert.len_div;
}
if (SDL_StreamInit(&device->streamer, stream_max_len, silence) <
0)
return -1;
device->use_streamer = 1;
/* istream_len should be the length of what we grab from the callback and feed to conversion,
so that we get close to spec_size. I.e. we want device.spec_size = istream_len * u / d
*/
istream_len =
device->spec.size * device->convert.len_div /
device->convert.len_mult;
}
395
#endif
396
397
398
/* stream_len = device->convert.len; */
stream_len = device->spec.size;
399
} else {
400
401
silence = device->spec.silence;
stream_len = device->spec.size;
402
}
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
/* Determine if the streamer is necessary here */
if (device->use_streamer == 1) {
/* This code is almost the same as the old code. The difference is, instead of reding
directly from the callback into "stream", then converting and sending the audio off,
we go: callback -> "istream" -> (conversion) -> streamer -> stream -> device.
However, reading and writing with streamer are done separately:
- We only call the callback and write to the streamer when the streamer does not
contain enough samples to output to the device.
- We only read from the streamer and tell the device to play when the streamer
does have enough samples to output.
This allows us to perform resampling in the conversion step, where the output of the
resampling process can be any number. We will have to see what a good size for the
stream's maximum length is, but I suspect 2*max(len_cvt, stream_len) is a good figure.
*/
while (device->enabled) {
/* Only read in audio if the streamer doesn't have enough already (if it does not have enough samples to output) */
if (SDL_StreamLength(&device->streamer) < stream_len) {
/* Set up istream */
if (device->convert.needed) {
if (device->convert.buf) {
istream = device->convert.buf;
} else {
continue;
}
} else {
istream = current_audio.impl.GetDeviceBuf(device);
if (istream == NULL) {
istream = device->fake_stream;
}
}
/* Read from the callback into the _input_ stream */
if (!device->paused) {
SDL_mutexP(device->mixer_lock);
(*fill) (udata, istream, istream_len);
SDL_mutexV(device->mixer_lock);
}
/* Convert the audio if necessary and write to the streamer */
if (device->convert.needed) {
SDL_ConvertAudio(&device->convert);
if (istream == NULL) {
istream = device->fake_stream;
}
/*SDL_memcpy(istream, device->convert.buf, device->convert.len_cvt); */
SDL_StreamWrite(&device->streamer, device->convert.buf,
device->convert.len_cvt);
} else {
SDL_StreamWrite(&device->streamer, istream, istream_len);
}
454
}
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
/* Only output audio if the streamer has enough to output */
if (SDL_StreamLength(&device->streamer) >= stream_len) {
/* Set up the output stream */
if (device->convert.needed) {
if (device->convert.buf) {
stream = device->convert.buf;
} else {
continue;
}
} else {
stream = current_audio.impl.GetDeviceBuf(device);
if (stream == NULL) {
stream = device->fake_stream;
}
}
/* Now read from the streamer */
SDL_StreamRead(&device->streamer, stream, stream_len);
/* Ready current buffer for play and change current buffer */
if (stream != device->fake_stream) {
current_audio.impl.PlayDevice(device);
}
/* Wait for an audio buffer to become available */
if (stream == device->fake_stream) {
SDL_Delay((device->spec.samples * 1000) /
device->spec.freq);
} else {
current_audio.impl.WaitDevice(device);
}
487
}
488
489
}
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
} else {
/* Otherwise, do not use the streamer. This is the old code. */
/* Loop, filling the audio buffers */
while (device->enabled) {
/* Fill the current buffer with sound */
if (device->convert.needed) {
if (device->convert.buf) {
stream = device->convert.buf;
} else {
continue;
}
} else {
stream = current_audio.impl.GetDeviceBuf(device);
if (stream == NULL) {
stream = device->fake_stream;
}
}
509
510
511
512
513
if (!device->paused) {
SDL_mutexP(device->mixer_lock);
(*fill) (udata, stream, stream_len);
SDL_mutexV(device->mixer_lock);
514
515
}
516
517
518
519
520
521
522
523
524
525
/* Convert the audio if necessary */
if (device->convert.needed) {
SDL_ConvertAudio(&device->convert);
stream = current_audio.impl.GetDeviceBuf(device);
if (stream == NULL) {
stream = device->fake_stream;
}
SDL_memcpy(stream, device->convert.buf,
device->convert.len_cvt);
}
526
527
528
529
530
531
532
533
534
535
536
537
/* Ready current buffer for play and change current buffer */
if (stream != device->fake_stream) {
current_audio.impl.PlayDevice(device);
}
/* Wait for an audio buffer to become available */
if (stream == device->fake_stream) {
SDL_Delay((device->spec.samples * 1000) / device->spec.freq);
} else {
current_audio.impl.WaitDevice(device);
}
538
539
540
541
}
}
/* Wait for the audio to drain.. */
542
current_audio.impl.WaitDone(device);
543
544
545
546
547
/* If necessary, deinit the streamer */
if (device->use_streamer == 1)
SDL_StreamDeinit(&device->streamer);
548
return (0);
549
550
}
551
552
static SDL_AudioFormat
553
SDL_ParseAudioFormat(const char *string)
554
{
555
#define CHECK_FMT_STRING(x) if (SDL_strcmp(string, #x) == 0) return AUDIO_##x
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
CHECK_FMT_STRING(U8);
CHECK_FMT_STRING(S8);
CHECK_FMT_STRING(U16LSB);
CHECK_FMT_STRING(S16LSB);
CHECK_FMT_STRING(U16MSB);
CHECK_FMT_STRING(S16MSB);
CHECK_FMT_STRING(U16SYS);
CHECK_FMT_STRING(S16SYS);
CHECK_FMT_STRING(U16);
CHECK_FMT_STRING(S16);
CHECK_FMT_STRING(S32LSB);
CHECK_FMT_STRING(S32MSB);
CHECK_FMT_STRING(S32SYS);
CHECK_FMT_STRING(S32);
CHECK_FMT_STRING(F32LSB);
CHECK_FMT_STRING(F32MSB);
CHECK_FMT_STRING(F32SYS);
CHECK_FMT_STRING(F32);
574
#undef CHECK_FMT_STRING
575
return 0;
576
577
}
578
579
int
SDL_GetNumAudioDrivers(void)
580
{
581
582
return (SDL_arraysize(bootstrap) - 1);
}
583
584
585
586
587
588
589
590
591
592
593
594
595
const char *
SDL_GetAudioDriver(int index)
{
if (index >= 0 && index < SDL_GetNumAudioDrivers()) {
return (bootstrap[index]->name);
}
return (NULL);
}
int
SDL_AudioInit(const char *driver_name)
{
596
597
598
int i = 0;
int initialized = 0;
int tried_to_init = 0;
599
600
int rc = 0;
int best_choice = -1;
601
602
if (SDL_WasInit(SDL_INIT_AUDIO)) {
603
SDL_AudioQuit(); /* shutdown driver if already running. */
604
605
}
606
607
SDL_memset(¤t_audio, '\0', sizeof(current_audio));
SDL_memset(open_devices, '\0', sizeof(open_devices));
608
609
/* Select the proper audio driver */
610
611
612
if (driver_name == NULL) {
driver_name = SDL_getenv("SDL_AUDIODRIVER");
}
613
614
615
616
for (i = 0; (!initialized) && (bootstrap[i]); ++i) {
/* make sure we should even try this driver before doing so... */
const AudioBootStrap *backend = bootstrap[i];
617
618
if (((driver_name) && (SDL_strcasecmp(backend->name, driver_name))) ||
((!driver_name) && (backend->demand_only))) {
619
continue;
620
}
621
622
tried_to_init = 1;
623
SDL_memset(¤t_audio, 0, sizeof(current_audio));
624
625
current_audio.name = backend->name;
current_audio.desc = backend->desc;
626
rc = backend->init(¤t_audio.impl);
627
if (rc == 2) { /* init'd, and devices available. Take it! */
628
629
initialized = 1;
best_choice = i;
630
} else if (rc == 1) { /* init'd, but can't see any devices. */
631
632
633
if (current_audio.impl.Deinitialize) {
current_audio.impl.Deinitialize();
}
634
635
636
637
638
639
640
641
642
643
644
645
646
if (best_choice == -1) {
best_choice = i;
}
}
}
/* No definite choice. Pick one that works but can't promise a device. */
if ((!initialized) && (best_choice != -1)) {
const AudioBootStrap *backend = bootstrap[best_choice];
SDL_memset(¤t_audio, 0, sizeof(current_audio));
current_audio.name = backend->name;
current_audio.desc = backend->desc;
initialized = (backend->init(¤t_audio.impl) > 0);
647
}
648
649
650
651
if (!initialized) {
/* specific drivers will set the error message if they fail... */
if (!tried_to_init) {
652
653
654
655
656
657
if (driver_name) {
SDL_SetError("%s not available", driver_name);
} else {
SDL_SetError("No available audio device");
}
}
658
659
660
SDL_memset(¤t_audio, 0, sizeof(current_audio));
return (-1); /* No driver was available, so fail. */
661
}
662
663
664
finalize_audio_entry_points();
665
return (0);
666
667
}
668
669
670
671
672
/*
* Get the current audio driver name
*/
const char *
SDL_GetCurrentAudioDriver()
673
{
674
return current_audio.name;
675
676
}
677
678
int
679
SDL_GetNumAudioDevices(int iscapture)
680
{
681
682
683
684
685
686
if (!SDL_WasInit(SDL_INIT_AUDIO)) {
return -1;
}
if ((iscapture) && (!current_audio.impl.HasCaptureSupport)) {
return 0;
}
687
688
689
if ((iscapture) && (current_audio.impl.OnlyHasDefaultInputDevice)) {
return 1;
690
691
}
692
693
if ((!iscapture) && (current_audio.impl.OnlyHasDefaultOutputDevice)) {
return 1;
694
695
}
696
697
698
699
700
701
702
703
704
705
return current_audio.impl.DetectDevices(iscapture);
}
const char *
SDL_GetAudioDeviceName(int index, int iscapture)
{
if (!SDL_WasInit(SDL_INIT_AUDIO)) {
SDL_SetError("Audio subsystem is not initialized");
return NULL;
706
}
707
708
709
710
if ((iscapture) && (!current_audio.impl.HasCaptureSupport)) {
SDL_SetError("No capture support");
return NULL;
711
}
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
if (index < 0) {
SDL_SetError("No such device");
return NULL;
}
if ((iscapture) && (current_audio.impl.OnlyHasDefaultInputDevice)) {
return DEFAULT_INPUT_DEVNAME;
}
if ((!iscapture) && (current_audio.impl.OnlyHasDefaultOutputDevice)) {
return DEFAULT_OUTPUT_DEVNAME;
}
return current_audio.impl.GetDeviceName(index, iscapture);
}
static void
731
close_audio_device(SDL_AudioDevice * device)
732
733
734
735
736
737
738
{
device->enabled = 0;
if (device->thread != NULL) {
SDL_WaitThread(device->thread, NULL);
}
if (device->mixer_lock != NULL) {
SDL_DestroyMutex(device->mixer_lock);
739
}
740
741
if (device->fake_stream != NULL) {
SDL_FreeAudioMem(device->fake_stream);
742
}
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
if (device->convert.needed) {
SDL_FreeAudioMem(device->convert.buf);
}
if (device->opened) {
current_audio.impl.CloseDevice(device);
device->opened = 0;
}
SDL_FreeAudioMem(device);
}
/*
* Sanity check desired AudioSpec for SDL_OpenAudio() in (orig).
* Fills in a sanitized copy in (prepared).
* Returns non-zero if okay, zero on fatal parameters in (orig).
*/
static int
760
prepare_audiospec(const SDL_AudioSpec * orig, SDL_AudioSpec * prepared)
761
{
762
SDL_memcpy(prepared, orig, sizeof(SDL_AudioSpec));
763
764
765
766
767
768
769
770
if (orig->callback == NULL) {
SDL_SetError("SDL_OpenAudio() passed a NULL callback");
return 0;
}
if (orig->freq == 0) {
const char *env = SDL_getenv("SDL_AUDIO_FREQUENCY");
771
772
if ((!env) || ((prepared->freq = SDL_atoi(env)) == 0)) {
prepared->freq = 22050; /* a reasonable default */
773
774
}
}
775
776
777
778
if (orig->format == 0) {
const char *env = SDL_getenv("SDL_AUDIO_FORMAT");
if ((!env) || ((prepared->format = SDL_ParseAudioFormat(env)) == 0)) {
779
prepared->format = AUDIO_S16; /* a reasonable default */
780
781
782
783
}
}
switch (orig->channels) {
784
785
case 0:{
const char *env = SDL_getenv("SDL_AUDIO_CHANNELS");
786
if ((!env) || ((prepared->channels = (Uint8) SDL_atoi(env)) == 0)) {
787
788
789
prepared->channels = 2; /* a reasonable default */
}
break;
790
}
791
792
793
794
795
796
case 1: /* Mono */
case 2: /* Stereo */
case 4: /* surround */
case 6: /* surround with center and lfe */
break;
default:
797
798
SDL_SetError("Unsupported number of audio channels.");
return 0;
799
}
800
801
802
if (orig->samples == 0) {
const char *env = SDL_getenv("SDL_AUDIO_SAMPLES");
803
if ((!env) || ((prepared->samples = (Uint16) SDL_atoi(env)) == 0)) {
804
805
806
807
808
809
810
811
/* Pick a default of ~46 ms at desired frequency */
/* !!! FIXME: remove this when the non-Po2 resampling is in. */
const int samples = (prepared->freq / 1000) * 46;
int power2 = 1;
while (power2 < samples) {
power2 *= 2;
}
prepared->samples = power2;
812
813
}
}
814
815
816
817
818
819
820
821
822
823
/* Calculate the silence and size of the audio specification */
SDL_CalculateAudioSpec(prepared);
return 1;
}
static SDL_AudioDeviceID
open_audio_device(const char *devname, int iscapture,
824
825
const SDL_AudioSpec * desired, SDL_AudioSpec * obtained,
int allowed_changes, int min_id)
826
827
{
SDL_AudioDeviceID id = 0;
828
SDL_AudioSpec _obtained;
829
SDL_AudioDevice *device;
830
SDL_bool build_cvt;
831
832
833
834
835
int i = 0;
if (!SDL_WasInit(SDL_INIT_AUDIO)) {
SDL_SetError("Audio subsystem is not initialized");
return 0;
836
}
837
838
839
840
if ((iscapture) && (!current_audio.impl.HasCaptureSupport)) {
SDL_SetError("No capture support");
return 0;
841
}
842
843
844
845
846
if (!obtained) {
obtained = &_obtained;
}
if (!prepare_audiospec(desired, obtained)) {
847
848
return 0;
}
849
850
851
852
853
/* If app doesn't care about a specific device, let the user override. */
if (devname == NULL) {
devname = SDL_getenv("SDL_AUDIO_DEVICE_NAME");
}
854
855
856
857
858
859
860
861
862
863
/*
* Catch device names at the high level for the simple case...
* This lets us have a basic "device enumeration" for systems that
* don't have multiple devices, but makes sure the device name is
* always NULL when it hits the low level.
*
* Also make sure that the simple case prevents multiple simultaneous
* opens of the default system device.
*/
864
865
866
867
868
869
870
if ((iscapture) && (current_audio.impl.OnlyHasDefaultInputDevice)) {
if ((devname) && (SDL_strcmp(devname, DEFAULT_INPUT_DEVNAME) != 0)) {
SDL_SetError("No such device");
return 0;
}
devname = NULL;
871
872
873
874
875
876
877
for (i = 0; i < SDL_arraysize(open_devices); i++) {
if ((open_devices[i]) && (open_devices[i]->iscapture)) {
SDL_SetError("Audio device already open");
return 0;
}
}
878
879
}
880
881
882
883
884
885
if ((!iscapture) && (current_audio.impl.OnlyHasDefaultOutputDevice)) {
if ((devname) && (SDL_strcmp(devname, DEFAULT_OUTPUT_DEVNAME) != 0)) {
SDL_SetError("No such device");
return 0;
}
devname = NULL;
886
887
888
889
890
891
892
893
for (i = 0; i < SDL_arraysize(open_devices); i++) {
if ((open_devices[i]) && (!open_devices[i]->iscapture)) {
SDL_SetError("Audio device already open");
return 0;
}
}
}
894
895
device = (SDL_AudioDevice *) SDL_AllocAudioMem(sizeof(SDL_AudioDevice));
896
897
898
if (device == NULL) {
SDL_OutOfMemory();
return 0;
899
}
900
SDL_memset(device, '\0', sizeof(SDL_AudioDevice));
901
device->spec = *obtained;
902
903
904
device->enabled = 1;
device->paused = 1;
device->iscapture = iscapture;
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
/* Create a semaphore for locking the sound buffers */
if (!current_audio.impl.SkipMixerLock) {
device->mixer_lock = SDL_CreateMutex();
if (device->mixer_lock == NULL) {
close_audio_device(device);
SDL_SetError("Couldn't create mixer lock");
return 0;
}
}
if (!current_audio.impl.OpenDevice(device, devname, iscapture)) {
close_audio_device(device);
return 0;
}
device->opened = 1;
921
922
/* Allocate a fake audio memory buffer */
923
924
925
device->fake_stream = SDL_AllocAudioMem(device->spec.size);
if (device->fake_stream == NULL) {
close_audio_device(device);
926
SDL_OutOfMemory();
927
return 0;
928
929
}
930
931
932
933
934
935
/* If the audio driver changes the buffer size, accept it */
if (device->spec.samples != obtained->samples) {
obtained->samples = device->spec.samples;
SDL_CalculateAudioSpec(obtained);
}
936
/* See if we need to do any conversion */
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
build_cvt = SDL_FALSE;
if (obtained->freq != device->spec.freq) {
if (allowed_changes & SDL_AUDIO_ALLOW_FREQUENCY_CHANGE) {
obtained->freq = device->spec.freq;
} else {
build_cvt = SDL_TRUE;
}
}
if (obtained->format != device->spec.format) {
if (allowed_changes & SDL_AUDIO_ALLOW_FORMAT_CHANGE) {
obtained->format = device->spec.format;
} else {
build_cvt = SDL_TRUE;
}
}
if (obtained->channels != device->spec.channels) {
if (allowed_changes & SDL_AUDIO_ALLOW_CHANNELS_CHANGE) {
obtained->channels = device->spec.channels;
} else {
build_cvt = SDL_TRUE;
}
}
if (build_cvt) {
960
/* Build an audio conversion block */
961
if (SDL_BuildAudioCVT(&device->convert,
962
963
obtained->format, obtained->channels,
obtained->freq,
964
965
966
967
device->spec.format, device->spec.channels,
device->spec.freq) < 0) {
close_audio_device(device);
return 0;
968
}
969
if (device->convert.needed) {
970
device->convert.len = (int) (((double) obtained->size) /
971
device->convert.len_ratio);
972
973
974
975
976
977
device->convert.buf =
(Uint8 *) SDL_AllocAudioMem(device->convert.len *
device->convert.len_mult);
if (device->convert.buf == NULL) {
close_audio_device(device);
978
SDL_OutOfMemory();
979
return 0;
980
981
982
}
}
}
983
984
/* Find an available device ID and store the structure... */
985
for (id = min_id - 1; id < SDL_arraysize(open_devices); id++) {
986
987
988
989
990
991
992
993
994
995
996
997
if (open_devices[id] == NULL) {
open_devices[id] = device;
break;
}
}
if (id == SDL_arraysize(open_devices)) {
SDL_SetError("Too many open audio devices");
close_audio_device(device);
return 0;
}
998
/* Start the audio thread if necessary */
999
if (!current_audio.impl.ProvidesOwnCallbackThread) {
1000
/* Start the audio thread */