Repository navigation
Expand file tree
/
Copy pathSDL_audio.h
More file actions
1512 lines (1432 loc) · 58.4 KB
/
Copy pathSDL_audio.h
File metadata and controls
1512 lines (1432 loc) · 58.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
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
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
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
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
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
Simple DirectMedia Layer
Copyright (C) 1997-2026 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
/* !!! FIXME: several functions in here need Doxygen comments. */
/**
* # CategoryAudio
*
* Access to the raw audio mixing buffer for the SDL library.
*/
#ifndef SDL_audio_h_
#define SDL_audio_h_
#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "SDL_endian.h"
#include "SDL_mutex.h"
#include "SDL_thread.h"
#include "SDL_rwops.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif
/**
* Audio format flags.
*
* These are what the 16 bits in SDL_AudioFormat currently mean...
* (Unspecified bits are always zero).
*
* ```
* ++-----------------------sample is signed if set
* ||
* || ++-----------sample is bigendian if set
* || ||
* || || ++---sample is float if set
* || || ||
* || || || +---sample bit size---+
* || || || | |
* 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
* ```
*
* There are macros in SDL 2.0 and later to query these bits.
*/
typedef Uint16 SDL_AudioFormat;
/**
* \name Audio flags
*/
/* @{ */
#define SDL_AUDIO_MASK_BITSIZE (0xFF)
#define SDL_AUDIO_MASK_DATATYPE (1<<8)
#define SDL_AUDIO_MASK_ENDIAN (1<<12)
#define SDL_AUDIO_MASK_SIGNED (1<<15)
#define SDL_AUDIO_BITSIZE(x) (x & SDL_AUDIO_MASK_BITSIZE)
#define SDL_AUDIO_ISFLOAT(x) (x & SDL_AUDIO_MASK_DATATYPE)
#define SDL_AUDIO_ISBIGENDIAN(x) (x & SDL_AUDIO_MASK_ENDIAN)
#define SDL_AUDIO_ISSIGNED(x) (x & SDL_AUDIO_MASK_SIGNED)
#define SDL_AUDIO_ISINT(x) (!SDL_AUDIO_ISFLOAT(x))
#define SDL_AUDIO_ISLITTLEENDIAN(x) (!SDL_AUDIO_ISBIGENDIAN(x))
#define SDL_AUDIO_ISUNSIGNED(x) (!SDL_AUDIO_ISSIGNED(x))
/**
* \name Audio format flags
*
* Defaults to LSB byte order.
*/
/* @{ */
#define AUDIO_U8 0x0008 /**< Unsigned 8-bit samples */
#define AUDIO_S8 0x8008 /**< Signed 8-bit samples */
#define AUDIO_U16LSB 0x0010 /**< Unsigned 16-bit samples */
#define AUDIO_S16LSB 0x8010 /**< Signed 16-bit samples */
#define AUDIO_U16MSB 0x1010 /**< As above, but big-endian byte order */
#define AUDIO_S16MSB 0x9010 /**< As above, but big-endian byte order */
#define AUDIO_U16 AUDIO_U16LSB
#define AUDIO_S16 AUDIO_S16LSB
/* @} */
/**
* \name int32 support
*/
/* @{ */
#define AUDIO_S32LSB 0x8020 /**< 32-bit integer samples */
#define AUDIO_S32MSB 0x9020 /**< As above, but big-endian byte order */
#define AUDIO_S32 AUDIO_S32LSB
/* @} */
/**
* \name float32 support
*/
/* @{ */
#define AUDIO_F32LSB 0x8120 /**< 32-bit floating point samples */
#define AUDIO_F32MSB 0x9120 /**< As above, but big-endian byte order */
#define AUDIO_F32 AUDIO_F32LSB
/* @} */
/**
* \name Native audio byte ordering
*/
/* @{ */
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
#define AUDIO_U16SYS AUDIO_U16LSB
#define AUDIO_S16SYS AUDIO_S16LSB
#define AUDIO_S32SYS AUDIO_S32LSB
#define AUDIO_F32SYS AUDIO_F32LSB
#else
#define AUDIO_U16SYS AUDIO_U16MSB
#define AUDIO_S16SYS AUDIO_S16MSB
#define AUDIO_S32SYS AUDIO_S32MSB
#define AUDIO_F32SYS AUDIO_F32MSB
#endif
/* @} */
/**
* \name Allow change flags
*
* Which audio format changes are allowed when opening a device.
*/
/* @{ */
#define SDL_AUDIO_ALLOW_FREQUENCY_CHANGE 0x00000001
#define SDL_AUDIO_ALLOW_FORMAT_CHANGE 0x00000002
#define SDL_AUDIO_ALLOW_CHANNELS_CHANGE 0x00000004
#define SDL_AUDIO_ALLOW_SAMPLES_CHANGE 0x00000008
#define SDL_AUDIO_ALLOW_ANY_CHANGE (SDL_AUDIO_ALLOW_FREQUENCY_CHANGE|SDL_AUDIO_ALLOW_FORMAT_CHANGE|SDL_AUDIO_ALLOW_CHANNELS_CHANGE|SDL_AUDIO_ALLOW_SAMPLES_CHANGE)
/* @} */
/* @} *//* Audio flags */
/**
* This function is called when the audio device needs more data.
*
* \param userdata An application-specific parameter saved in the
* SDL_AudioSpec structure.
* \param stream A pointer to the audio data buffer.
* \param len Length of **stream** in bytes.
*/
typedef void (SDLCALL * SDL_AudioCallback) (void *userdata, Uint8 * stream,
int len);
/**
* The calculated values in this structure are calculated by SDL_OpenAudio().
*
* For multi-channel audio, the default SDL channel mapping is:
*
* ```
* 2: FL FR (stereo)
* 3: FL FR LFE (2.1 surround)
* 4: FL FR BL BR (quad)
* 5: FL FR LFE BL BR (4.1 surround)
* 6: FL FR FC LFE SL SR (5.1 surround - last two can also be BL BR)
* 7: FL FR FC LFE BC SL SR (6.1 surround)
* 8: FL FR FC LFE BL BR SL SR (7.1 surround)
* ```
*/
typedef struct SDL_AudioSpec
{
int freq; /**< DSP frequency -- samples per second */
SDL_AudioFormat format; /**< Audio data format */
Uint8 channels; /**< Number of channels: 1 mono, 2 stereo */
Uint8 silence; /**< Audio buffer silence value (calculated) */
Uint16 samples; /**< Audio buffer size in sample FRAMES (total samples divided by channel count) */
Uint16 padding; /**< Necessary for some compile environments */
Uint32 size; /**< Audio buffer size in bytes (calculated) */
SDL_AudioCallback callback; /**< Callback that feeds the audio device (NULL to use SDL_QueueAudio()). */
void *userdata; /**< Userdata passed to callback (ignored for NULL callbacks). */
} SDL_AudioSpec;
struct SDL_AudioCVT;
typedef void (SDLCALL * SDL_AudioFilter) (struct SDL_AudioCVT * cvt,
SDL_AudioFormat format);
/**
* Upper limit of filters in SDL_AudioCVT
*
* The maximum number of SDL_AudioFilter functions in SDL_AudioCVT is
* currently limited to 9. The SDL_AudioCVT.filters array has 10 pointers, one
* of which is the terminating NULL pointer.
*/
#define SDL_AUDIOCVT_MAX_FILTERS 9
/**
* \struct SDL_AudioCVT
* \brief A structure to hold a set of audio conversion filters and buffers.
*
* Note that various parts of the conversion pipeline can take advantage
* of SIMD operations (like SSE2, for example). SDL_AudioCVT doesn't require
* you to pass it aligned data, but can possibly run much faster if you
* set both its (buf) field to a pointer that is aligned to 16 bytes, and its
* (len) field to something that's a multiple of 16, if possible.
*/
#if defined(__GNUC__) && !defined(__CHERI_PURE_CAPABILITY__)
/* This structure is 84 bytes on 32-bit architectures, make sure GCC doesn't
pad it out to 88 bytes to guarantee ABI compatibility between compilers.
This is not a concern on CHERI architectures, where pointers must be stored
at aligned locations otherwise they will become invalid, and thus structs
containing pointers cannot be packed without giving a warning or error.
vvv
The next time we rev the ABI, make sure to size the ints and add padding.
*/
#define SDL_AUDIOCVT_PACKED __attribute__((packed))
#else
#define SDL_AUDIOCVT_PACKED
#endif
/* */
typedef struct
8BD0
SDL_AudioCVT
{
int needed; /**< Set to 1 if conversion possible */
SDL_AudioFormat src_format; /**< Source audio format */
SDL_AudioFormat dst_format; /**< Target audio format */
double rate_incr; /**< Rate conversion increment */
Uint8 *buf; /**< Buffer to hold entire audio data */
int len; /**< Length of original audio buffer */
int len_cvt; /**< Length of converted audio buffer */
int len_mult; /**< buffer must be len*len_mult big */
double len_ratio; /**< Given len, final size is len*len_ratio */
SDL_AudioFilter filters[SDL_AUDIOCVT_MAX_FILTERS + 1]; /**< NULL-terminated list of filter functions */
int filter_index; /**< Current audio conversion function */
} SDL_AUDIOCVT_PACKED SDL_AudioCVT;
/* Function prototypes */
/**
* \name Driver discovery functions
*
* These functions return the list of built in audio drivers, in the
* order that they are normally initialized by default.
*/
/* @{ */
/**
* Use this function to get the number of built-in audio drivers.
*
* This function returns a hardcoded number. This never returns a negative
* value; if there are no drivers compiled into this build of SDL, this
* function returns zero. The presence of a driver in this list does not mean
* it will function, it just means SDL is capable of interacting with that
* interface. For example, a build of SDL might have esound support, but if
* there's no esound server available, SDL's esound driver would fail if used.
*
* By default, SDL tries all drivers, in its preferred order, until one is
* found to be usable.
*
* \returns the number of built-in audio drivers.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetAudioDriver
*/
extern DECLSPEC int SDLCALL SDL_GetNumAudioDrivers(void);
/**
* Use this function to get the name of a built in audio driver.
*
* The list of audio drivers is given in the order that they are normally
* initialized by default; the drivers that seem more reasonable to choose
* first (as far as the SDL developers believe) are earlier in the list.
*
* The names of drivers are all simple, low-ASCII identifiers, like "alsa",
* "coreaudio" or "xaudio2". These never have Unicode characters, and are not
* meant to be proper names.
*
* \param index the index of the audio driver; the value ranges from 0 to
* SDL_GetNumAudioDrivers() - 1.
* \returns the name of the audio driver at the requested index, or NULL if an
* invalid index was specified.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetNumAudioDrivers
*/
extern DECLSPEC const char *SDLCALL SDL_GetAudioDriver(int index);
/* @} */
/**
* \name Initialization and cleanup
*
* \internal These functions are used internally, and should not be used unless
* you have a specific need to specify the audio driver you want to
* use. You should normally use SDL_Init() or SDL_InitSubSystem().
*/
/* @{ */
/**
* Use this function to initialize a particular audio driver.
*
* This function is used internally, and should not be used unless you have a
* specific need to designate the audio driver you want to use. You should
* normally use SDL_Init() or SDL_InitSubSystem().
*
* \param driver_name the name of the desired audio driver.
* \returns 0 on success or a negative error code on failure; call
* SDL_GetError() for more information.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_AudioQuit
*/
extern DECLSPEC int SDLCALL SDL_AudioInit(const char *driver_name);
/**
* Use this function to shut down audio if you initialized it with
* SDL_AudioInit().
*
* This function is used internally, and should not be used unless you have a
* specific need to specify the audio driver you want to use. You should
* normally use SDL_Quit() or SDL_QuitSubSystem().
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_AudioInit
*/
extern DECLSPEC void SDLCALL SDL_AudioQuit(void);
/* @} */
/**
* Get the name of the current audio driver.
*
* The returned string points to internal static memory and thus never becomes
* invalid, even if you quit the audio subsystem and initialize a new driver
* (although such a case would return a different static string from another
* call to this function, of course). As such, you should not modify or free
* the returned string.
*
* \returns the name of the current audio driver or NULL if no driver has been
* initialized.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_AudioInit
*/
extern DECLSPEC const char *SDLCALL SDL_GetCurrentAudioDriver(void);
/**
* This function is a legacy means of opening the audio device.
*
* This function remains for compatibility with SDL 1.2, but also because it's
* slightly easier to use than the new functions in SDL 2.0. The new, more
* powerful, and preferred way to do this is SDL_OpenAudioDevice().
*
* This function is roughly equivalent to:
*
* ```c
* SDL_OpenAudioDevice(NULL, 0, desired, obtained, SDL_AUDIO_ALLOW_ANY_CHANGE);
* ```
*
* With two notable exceptions:
*
* - If `obtained` is NULL, we use `desired` (and allow no changes), which
* means desired will be modified to have the correct values for silence,
* etc, and SDL will convert any differences between your app's specific
* request and the hardware behind the scenes.
* - The return value is always success or failure, and not a device ID, which
* means you can only have one device open at a time with this function.
*
* \param desired an SDL_AudioSpec structure representing the desired output
* format. Please refer to the SDL_OpenAudioDevice
* documentation for details on how to prepare this structure.
* \param obtained an SDL_AudioSpec structure filled in with the actual
* parameters, or NULL.
* \returns 0 if successful, placing the actual hardware parameters in the
* structure pointed to by `obtained`.
*
* If `obtained` is NULL, the audio data passed to the callback
* function will be guaranteed to be in the requested format, and
* will be automatically converted to the actual hardware audio
* format if necessary. If `obtained` is NULL, `desired` will have
* fields modified.
*
* This function returns a negative error code on failure to open the
* audio device or failure to set up the audio thread; call
* SDL_GetError() for more information.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_CloseAudio
* \sa SDL_LockAudio
* \sa SDL_PauseAudio
* \sa SDL_UnlockAudio
*/
extern DECLSPEC int SDLCALL SDL_OpenAudio(SDL_AudioSpec * desired,
SDL_AudioSpec * obtained);
/**
* SDL Audio Device IDs.
*
* A successful call to SDL_OpenAudio() is always device id 1, and legacy SDL
* audio APIs assume you want this device ID. SDL_OpenAudioDevice() calls
* always returns devices >= 2 on success. The legacy calls are good both for
* backwards compatibility and when you don't care about multiple, specific,
* or capture devices.
*/
typedef Uint32 SDL_AudioDeviceID;
/**
* Get the number of built-in audio devices.
*
* This function is only valid after successfully initializing the audio
* subsystem.
*
* Note that audio capture support is not implemented as of SDL 2.0.4, so the
* `iscapture` parameter is for future expansion and should always be zero for
* now.
*
* This function will return -1 if an explicit list of devices can't be
* determined. Returning -1 is not an error. For example, if SDL is set up to
* talk to a remote audio server, it can't list every one available on the
* Internet, but it will still allow a specific host to be specified in
* SDL_OpenAudioDevice().
*
* In many common cases, when this function returns a value <= 0, it can still
* successfully open the default device (NULL for first argument of
* SDL_OpenAudioDevice()).
*
* This function may trigger a complete redetect of available hardware. It
* should not be called for each iteration of a loop, but rather once at the
* start of a loop:
*
* ```c
* // Don't do this:
* for (int i = 0; i < SDL_GetNumAudioDevices(0); i++)
*
* // do this instead:
* const int count = SDL_GetNumAudioDevices(0);
* for (int i = 0; i < count; ++i) { do_something_here(); }
* ```
*
* \param iscapture zero to request playback devices, non-zero to request
* recording devices.
* \returns the number of available devices exposed by the current driver or
* -1 if an explicit list of devices can't be determined. A return
* value of -1 does not necessarily mean an error condition.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetAudioDeviceName
* \sa SDL_OpenAudioDevice
*/
extern DECLSPEC int SDLCALL SDL_GetNumAudioDevices(int iscapture);
/**
* Get the human-readable name of a specific audio device.
*
* This function is only valid after successfully initializing the audio
* subsystem. The values returned by this function reflect the latest call to
* SDL_GetNumAudioDevices(); re-call that function to redetect available
* hardware.
*
* The string returned by this function is UTF-8 encoded, read-only, and
* managed internally. You are not to free it. If you need to keep the string
* for any length of time, you should make your own copy of it, as it will be
* invalid next time any of several other SDL functions are called.
*
* \param index the index of the audio device; valid values range from 0 to
* SDL_GetNumAudioDevices() - 1.
* \param iscapture non-zero to query the list of recording devices, zero to
* query the list of output devices.
* \returns the name of the audio device at the requested index, or NULL on
* error.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetNumAudioDevices
* \sa SDL_GetDefaultAudioInfo
*/
extern DECLSPEC const char *SDLCALL SDL_GetAudioDeviceName(int index,
int iscapture);
/**
* Get the preferred audio format of a specific audio device.
*
* This function is only valid after a successfully initializing the audio
* subsystem. The values returned by this function reflect the latest call to
* SDL_GetNumAudioDevices(); re-call that function to redetect available
* hardware.
*
* `spec` will be filled with the sample rate, sample format, and channel
* count.
*
* \param index the index of the audio device; valid values range from 0 to
* SDL_GetNumAudioDevices() - 1.
* \param iscapture non-zero to query the list of recording devices, zero to
* query the list of output devices.
* \param spec The SDL_AudioSpec to be initialized by this function.
* \returns 0 on success, nonzero on error.
*
* \since This function is available since SDL 2.0.16.
*
* \sa SDL_GetNumAudioDevices
* \sa SDL_GetDefaultAudioInfo
*/
extern DECLSPEC int SDLCALL SDL_GetAudioDeviceSpec(int index,
int iscapture,
SDL_AudioSpec *spec);
/**
* Get the name and preferred format of the default audio device.
*
* Some (but not all!) platforms have an isolated mechanism to get information
* about the "default" device. This can actually be a completely different
* device that's not in the list you get from SDL_GetAudioDeviceSpec(). It can
* even be a network address! (This is discussed in SDL_OpenAudioDevice().)
*
* As a result, this call is not guaranteed to be performant, as it can query
* the sound server directly every time, unlike the other query functions. You
* should call this function sparingly!
*
* `spec` will be filled with the sample rate, sample format, and channel
* count, if a default device exists on the system. If `name` is provided,
* will be filled with either a dynamically-allocated UTF-8 string or NULL.
*
* \param name A pointer to be filled with the name of the default device (can
* be NULL). Please call SDL_free() when you are done with this
* pointer!
* \param spec The SDL_AudioSpec to be initialized by this function.
* \param iscapture non-zero to query the default recording device, zero to
* query the default output device.
* \returns 0 on success, nonzero on error.
*
* \since This function is available since SDL 2.24.0.
*
* \sa SDL_GetAudioDeviceName
* \sa SDL_GetAudioDeviceSpec
* \sa SDL_OpenAudioDevice
*/
extern DECLSPEC int SDLCALL SDL_GetDefaultAudioInfo(char **name,
SDL_AudioSpec *spec,
int iscapture);
/**
* Open a specific audio device.
*
* SDL_OpenAudio(), unlike this function, always acts on device ID 1. As such,
* this function will never return a 1 so as not to conflict with the legacy
* function.
*
* Please note that SDL 2.0 before 2.0.5 did not support recording; as such,
* this function would fail if `iscapture` was not zero. Starting with SDL
* 2.0.5, recording is implemented and this value can be non-zero.
*
* Passing in a `device` name of NULL requests the most reasonable default
* (and is equivalent to what SDL_OpenAudio() does to choose a device). The
* `device` name is a UTF-8 string reported by SDL_GetAudioDeviceName(), but
* some drivers allow arbitrary and driver-specific strings, such as a
* hostname/IP address for a remote audio server, or a filename in the
* diskaudio driver.
*
* An opened audio device starts out paused, and should be enabled for playing
* by calling SDL_PauseAudioDevice(devid, 0) when you are ready for your audio
* callback function to be called. Since the audio driver may modify the
* requested size of the audio buffer, you should allocate any local mixing
* buffers after you open the audio device.
*
* The audio callback runs in a separate thread in most cases; you can prevent
* race conditions between your callback and other threads without fully
* pausing playback with SDL_LockAudioDevice(). For more information about the
* callback, see SDL_AudioSpec.
*
* Managing the audio spec via 'desired' and 'obtained':
*
* When filling in the desired audio spec structure:
*
* - `desired->freq` should be the frequency in sample-frames-per-second (Hz).
* - `desired->format` should be the audio format (`AUDIO_S16SYS`, etc).
* - `desired->samples` is the desired size of the audio buffer, in _sample
* frames_ (with stereo output, two samples--left and right--would make a
* single sample frame). This number should be a power of two, and may be
* adjusted by the audio driver to a value more suitable for the hardware.
* Good values seem to range between 512 and 4096 inclusive, depending on
* the application and CPU speed. Smaller values reduce latency, but can
* lead to underflow if the application is doing heavy processing and cannot
* fill the audio buffer in time. Note that the number of sample frames is
* directly related to time by the following formula: `ms =
* (sampleframes*1000)/freq`
* - `desired->size` is the size in _bytes_ of the audio buffer, and is
* calculated by SDL_OpenAudioDevice(). You don't initialize this.
* - `desired->silence` is the value used to set the buffer to silence, and is
* calculated by SDL_OpenAudioDevice(). You don't initialize this.
* - `desired->callback` should be set to a function that will be called when
* the audio device is ready for more data. It is passed a pointer to the
* audio buffer, and the length in bytes of the audio buffer. This function
* usually runs in a separate thread, and so you should protect data
* structures that it accesses by calling SDL_LockAudioDevice() and
* SDL_UnlockAudioDevice() in your code. Alternately, you may pass a NULL
* pointer here, and call SDL_QueueAudio() with some frequency, to queue
* more audio samples to be played (or for capture devices, call
* SDL_DequeueAudio() with some frequency, to obtain audio samples).
* - `desired->userdata` is passed as the first parameter to your callback
* function. If you passed a NULL callback, this value is ignored.
*
* `allowed_changes` can have the following flags OR'd together:
*
* - `SDL_AUDIO_ALLOW_FREQUENCY_CHANGE`
* - `SDL_AUDIO_ALLOW_FORMAT_CHANGE`
* - `SDL_AUDIO_ALLOW_CHANNELS_CHANGE`
* - `SDL_AUDIO_ALLOW_SAMPLES_CHANGE`
* - `SDL_AUDIO_ALLOW_ANY_CHANGE`
*
* These flags specify how SDL should behave when a device cannot offer a
* specific feature. If the application requests a feature that the hardware
* doesn't offer, SDL will always try to get the closest equivalent.
*
* For example, if you ask for float32 audio format, but the sound card only
* supports int16, SDL will set the hardware to int16. If you had set
* SDL_AUDIO_ALLOW_FORMAT_CHANGE, SDL will change the format in the `obtained`
* structure. If that flag was *not* set, SDL will prepare to convert your
* callback's float32 audio to int16 before feeding it to the hardware and
* will keep the originally requested format in the `obtained` structure.
*
* The resulting audio specs, varying depending on hardware and on what
* changes were allowed, will then be written back to `obtained`.
*
* If your application can only handle one specific data format, pass a zero
* for `allowed_changes` and let SDL transparently handle any differences.
*
* \param device a UTF-8 string reported by SDL_GetAudioDeviceName() or a
* driver-specific name as appropriate. NULL requests the most
* reasonable default device.
* \param iscapture non-zero to specify a device should be opened for
* recording, not playback.
* \param desired an SDL_AudioSpec structure representing the desired output
* format; see SDL_OpenAudio() for more information.
* \param obtained an SDL_AudioSpec structure filled in with the actual output
* format; see SDL_OpenAudio() for more information.
* \param allowed_changes 0, or one or more flags OR'd together.
* \returns a valid device ID > 0 on success or 0 on failure; call
* SDL_GetError() for more information.
*
* For compatibility with SDL 1.2, this will never return 1, since
* SDL reserves that ID for the legacy SDL_OpenAudio() function.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_CloseAudioDevice
* \sa SDL_GetAudioDeviceName
* \sa SDL_LockAudioDevice
* \sa SDL_OpenAudio
* \sa SDL_PauseAudioDevice
* \sa SDL_UnlockAudioDevice
*/
extern DECLSPEC SDL_AudioDeviceID SDLCALL SDL_OpenAudioDevice(
const char *device,
int iscapture,
const SDL_AudioSpec *desired,
SDL_AudioSpec *obtained,
int allowed_changes);
/**
* \name Audio state
*
* Get the current audio state.
*/
/* @{ */
typedef enum
{
SDL_AUDIO_STOPPED = 0,
SDL_AUDIO_PLAYING,
SDL_AUDIO_PAUSED
} SDL_AudioStatus;
/**
* This function is a legacy means of querying the audio device.
*
* New programs might want to use SDL_GetAudioDeviceStatus() instead. This
* function is equivalent to calling...
*
* ```c
* SDL_GetAudioDeviceStatus(1);
* ```
*
* ...and is only useful if you used the legacy SDL_OpenAudio() function.
*
* \returns the SDL_AudioStatus of the audio device opened by SDL_OpenAudio().
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetAudioDeviceStatus
*/
extern DECLSPEC SDL_AudioStatus SDLCALL SDL_GetAudioStatus(void);
/**
* Use this function to get the current audio state of an audio device.
*
* \param dev the ID of an audio device previously opened with
* SDL_OpenAudioDevice().
* \returns the SDL_AudioStatus of the specified audio device.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_PauseAudioDevice
*/
extern DECLSPEC SDL_AudioStatus SDLCALL SDL_GetAudioDeviceStatus(SDL_AudioDeviceID dev);
/* @} *//* Audio State */
/**
* \name Pause audio functions
*
* These functions pause and unpause the audio callback processing.
* They should be called with a parameter of 0 after opening the audio
* device to start playing sound. This is so you can safely initialize
* data for your callback function after opening the audio device.
* Silence will be written to the audio device during the pause.
*/
/* @{ */
/**
* This function is a legacy means of pausing the audio device.
*
* New programs might want to use SDL_PauseAudioDevice() instead. This
* function is equivalent to calling...
*
* ```c
* SDL_PauseAudioDevice(1, pause_on);
* ```
*
* ...and is only useful if you used the legacy SDL_OpenAudio() function.
*
* \param pause_on non-zero to pause, 0 to unpause.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_GetAudioStatus
* \sa SDL_PauseAudioDevice
*/
extern DECLSPEC void SDLCALL SDL_PauseAudio(int pause_on);
/**
* Use this function to pause and unpause audio playback on a specified
* device.
*
* This function pauses and unpauses the audio callback processing for a given
* device. Newly-opened audio devices start in the paused state, so you must
* call this function with **pause_on**=0 after opening the specified audio
* device to start playing sound. This allows you to safely initialize data
* for your callback function after opening the audio device. Silence will be
* written to the audio device while paused, and the audio callback is
* guaranteed to not be called. Pausing one device does not prevent other
* unpaused devices from running their callbacks.
*
* Pausing state does not stack; even if you pause a device several times, a
* single unpause will start the device playing again, and vice versa. This is
* different from how SDL_LockAudioDevice() works.
*
* If you just need to protect a few variables from race conditions vs your
* callback, you shouldn't pause the audio device, as it will lead to dropouts
* in the audio playback. Instead, you should use SDL_LockAudioDevice().
*
* \param dev a device opened by SDL_OpenAudioDevice().
* \param pause_on non-zero to pause, 0 to unpause.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_LockAudioDevice
*/
extern DECLSPEC void SDLCALL SDL_PauseAudioDevice(SDL_AudioDeviceID dev,
int pause_on);
/* @} *//* Pause audio functions */
/**
* Load the audio data of a WAVE file into memory.
*
* Loading a WAVE file requires `src`, `spec`, `audio_buf` and `audio_len` to
* be valid pointers. The entire data portion of the file is then loaded into
* memory and decoded if necessary.
*
* If `freesrc` is non-zero, the data source gets automatically closed and
* freed before the function returns.
*
* Supported formats are RIFF WAVE files with the formats PCM (8, 16, 24, and
* 32 bits), IEEE Float (32 bits), Microsoft ADPCM and IMA ADPCM (4 bits), and
* A-law and mu-law (8 bits). Other formats are currently unsupported and
* cause an error.
*
* If this function succeeds, the pointer returned by it is equal to `spec`
* and the pointer to the audio data allocated by the function is written to
* `audio_buf` and its length in bytes to `audio_len`. The SDL_AudioSpec
* members `freq`, `channels`, and `format` are set to the values of the audio
* data in the buffer. The `samples` member is set to a sane default and all
* others are set to zero.
*
* It's necessary to use SDL_FreeWAV() to free the audio data returned in
* `audio_buf` when it is no longer used.
*
* Because of the underspecification of the .WAV format, there are many
* problematic files in the wild that cause issues with strict decoders. To
* provide compatibility with these files, this decoder is lenient in regards
* to the truncation of the file, the fact chunk, and the size of the RIFF
* chunk. The hints `SDL_HINT_WAVE_RIFF_CHUNK_SIZE`,
* `SDL_HINT_WAVE_TRUNCATION`, and `SDL_HINT_WAVE_FACT_CHUNK` can be used to
* tune the behavior of the loading process.
*
* Any file that is invalid (due to truncation, corruption, or wrong values in
* the headers), too big, or unsupported causes an error. Additionally, any
* critical I/O error from the data source will terminate the loading process
* with an error. The function returns NULL on error and in all cases (with
* the exception of `src` being NULL), an appropriate error message will be
* set.
*
* It is required that the data source supports seeking.
*
* Example:
*
* ```c
* SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, &spec, &buf, &len);
* ```
*
* Note that the SDL_LoadWAV macro does this same thing for you, but in a less
* messy way:
*
* ```c
* SDL_LoadWAV("sample.wav", &spec, &buf, &len);
* ```
*
* \param src The data source for the WAVE data.
* \param freesrc If non-zero, SDL will _always_ free the data source.
* \param spec An SDL_AudioSpec that will be filled in with the wave file's
* format details.
* \param audio_buf A pointer filled with the audio data, allocated by the
* function.
* \param audio_len A pointer filled with the length of the audio data buffer
* in bytes.
* \returns This function, if successfully called, returns `spec`, which will
* be filled with the audio data format of the wave source data.
* `audio_buf` will be filled with a pointer to an allocated buffer
* containing the audio data, and `audio_len` is filled with the
* length of that audio buffer in bytes.
*
* This function returns NULL if the .WAV file cannot be opened, uses
* an unknown data format, or is corrupt; call SDL_GetError() for
* more information.
*
* When the application is done with the data returned in
* `audio_buf`, it should call SDL_FreeWAV() to dispose of it.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_FreeWAV
* \sa SDL_LoadWAV
*/
extern DECLSPEC SDL_AudioSpec *SDLCALL SDL_LoadWAV_RW(SDL_RWops * src,
int freesrc,
SDL_AudioSpec * spec,
Uint8 ** audio_buf,
Uint32 * audio_len);
/**
* Loads a WAV from a file.
*
* Compatibility convenience function.
*/
#define SDL_LoadWAV(file, spec, audio_buf, audio_len) \
SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
/**
* Free data previously allocated with SDL_LoadWAV() or SDL_LoadWAV_RW().
*
* After a WAVE file has been opened with SDL_LoadWAV() or SDL_LoadWAV_RW()
* its data can eventually be freed with SDL_FreeWAV(). It is safe to call
* this function with a NULL pointer.
*
* \param audio_buf a pointer to the buffer created by SDL_LoadWAV() or
* SDL_LoadWAV_RW().
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_LoadWAV
* \sa SDL_LoadWAV_RW
*/
extern DECLSPEC void SDLCALL SDL_FreeWAV(Uint8 * audio_buf);
/**
* Initialize an SDL_AudioCVT structure for conversion.
*
* Before an SDL_AudioCVT structure can be used to convert audio data it must
* be initialized with source and destination information.
*
* This function will zero out every field of the SDL_AudioCVT, so it must be
* called before the application fills in the final buffer information.
*
* Once this function has returned successfully, and reported that a
* conversion is necessary, the application fills in the rest of the fields in
* SDL_AudioCVT, now that it knows how large a buffer it needs to allocate,
* and then can call SDL_ConvertAudio() to complete the conversion.
*
* \param cvt an SDL_AudioCVT structure filled in with audio conversion
* information.
* \param src_format the source format of the audio data; for more info see
* SDL_AudioFormat.
* \param src_channels the number of channels in the source.
* \param src_rate the frequency (sample-frames-per-second) of the source.
* \param dst_format the destination format of the audio data; for more info
* see SDL_AudioFormat.
* \param dst_channels the number of channels in the destination.
* \param dst_rate the frequency (sample-frames-per-second) of the
* destination.
* \returns 1 if the audio filter is prepared, 0 if no conversion is needed,
* or a negative error code on failure; call SDL_GetError() for more
* information.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_ConvertAudio
*/
extern DECLSPEC int SDLCALL SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
SDL_AudioFormat src_format,
Uint8 src_channels,
int src_rate,
SDL_AudioFormat dst_format,
Uint8 dst_channels,
int dst_rate);
/**
* Convert audio data to a desired audio format.
*
* This function does the actual audio data conversion, after the application
* has called SDL_BuildAudioCVT() to prepare the conversion information and
* then filled in the buffer details.
*
* Once the application has initialized the `cvt` structure using
* SDL_BuildAudioCVT(), allocated an audio buffer and filled it with audio
* data in the source format, this function will convert the buffer, in-place,
* to the desired format.
*
* The data conversion may go through several passes; any given pass may
* possibly temporarily increase the size of the data. For example, SDL might
* expand 16-bit data to 32 bits before resampling to a lower frequency,
* shrinking the data size after having grown it briefly. Since the supplied
* buffer will be both the source and destination, converting as necessary
* in-place, the application must allocate a buffer that will fully contain
* the data during its largest conversion pass. After SDL_BuildAudioCVT()
* returns, the application should set the `cvt->len` field to the size, in
* bytes, of the source data, and allocate a buffer that is `cvt->len *
* cvt->len_mult` bytes long for the `buf` field.
*
* The source data should be copied into this buffer before the call to
* SDL_ConvertAudio(). Upon successful return, this buffer will contain the
* converted audio, and `cvt->len_cvt` will be the size of the converted data,
* in bytes. Any bytes in the buffer past `cvt->len_cvt` are undefined once
* this function returns.
*
* \param cvt an SDL_AudioCVT structure that was previously set up by
* SDL_BuildAudioCVT().
* \returns 0 if the conversion was completed successfully or a negative error
* code on failure; call SDL_GetError() for more information.
*
* \since This function is available since SDL 2.0.0.
*
* \sa SDL_BuildAudioCVT
*/
extern DECLSPEC int SDLCALL SDL_ConvertAudio(SDL_AudioCVT * cvt);
/* SDL_AudioStream is a new audio conversion interface.
The benefits vs SDL_AudioCVT:
- it can handle resampling data in chunks without generating
artifacts, when it doesn't have the complete buffer available.
- it can handle incoming data in any variable size.
- You push data as you have it, and pull it when you need it
*/
/* this is opaque to the outside world. */
struct _SDL_AudioStream;
typedef struct _SDL_AudioStream SDL_AudioStream;
/**
* Create a new audio stream.
*
* \param src_format The format of the source audio.
* \param src_channels The number of channels of the source audio.
* \param src_rate The sampling rate of the source audio.
* \param dst_format The format of the desired audio output.
* \param dst_channels The number of channels of the desired audio output.
* \param dst_rate The sampling rate of the desired audio output.
* \returns 0 on success, or -1 on error.
*