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1 #ifndef PORTAUDIO_H
2 #define PORTAUDIO_H
3 /*
4 * $Id: portaudio.h 1337 2008-02-15 07:32:09Z rossb $
5 * PortAudio Portable Real-Time Audio Library
6 * PortAudio API Header File
7 * Latest version available at: http://www.portaudio.com/
8 *
9 * Copyright (c) 1999-2002 Ross Bencina and Phil Burk
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining
12 * a copy of this software and associated documentation files
13 * (the "Software"), to deal in the Software without restriction,
14 * including without limitation the rights to use, copy, modify, merge,
15 * publish, distribute, sublicense, and/or sell copies of the Software,
16 * and to permit persons to whom the Software is furnished to do so,
17 * subject to the following conditions:
18 *
19 * The above copyright notice and this permission notice shall be
20 * included in all copies or substantial portions of the Software.
21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
23 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
25 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
26 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
27 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
28 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
29 */
30
31 /*
32 * The text above constitutes the entire PortAudio license; however,
33 * the PortAudio community also makes the following non-binding requests:
34 *
35 * Any person wishing to distribute modifications to the Software is
36 * requested to send the modifications to the original developer so that
37 * they can be incorporated into the canonical version. It is also
38 * requested that these non-binding requests be included along with the
39 * license above.
40 */
41
42 /** @file
43 @ingroup public_header
44 @brief The portable PortAudio API.
45 */
46
47
48 #ifdef __cplusplus
49 extern "C"
50 {
51 #endif /* __cplusplus */
52
53
54 /** Retrieve the release number of the currently running PortAudio build,
55 eg 1900.
56 */
57 int Pa_GetVersion( void );
58
59
60 /** Retrieve a textual description of the current PortAudio build,
61 eg "PortAudio V19-devel 13 October 2002".
62 */
63 const char* Pa_GetVersionText( void );
64
65
66 /** Error codes returned by PortAudio functions.
67 Note that with the exception of paNoError, all PaErrorCodes are negative.
68 */
69
70 typedef int PaError;
71 typedef enum PaErrorCode
72 {
73 paNoError = 0,
74
75 paNotInitialized = -10000,
76 paUnanticipatedHostError,
77 paInvalidChannelCount,
78 paInvalidSampleRate,
79 paInvalidDevice,
80 paInvalidFlag,
81 paSampleFormatNotSupported,
82 paBadIODeviceCombination,
83 paInsufficientMemory,
84 paBufferTooBig,
85 paBufferTooSmall,
86 paNullCallback,
87 paBadStreamPtr,
88 paTimedOut,
89 paInternalError,
90 paDeviceUnavailable,
91 paIncompatibleHostApiSpecificStreamInfo,
92 paStreamIsStopped,
93 paStreamIsNotStopped,
94 paInputOverflowed,
95 paOutputUnderflowed,
96 paHostApiNotFound,
97 paInvalidHostApi,
98 paCanNotReadFromACallbackStream, /**< @todo review error code name */
99 paCanNotWriteToACallbackStream, /**< @todo review error code name */
100 paCanNotReadFromAnOutputOnlyStream, /**< @todo review error code name */
101 paCanNotWriteToAnInputOnlyStream, /**< @todo review error code name */
102 paIncompatibleStreamHostApi,
103 paBadBufferPtr
104 } PaErrorCode;
105
106
107 /** Translate the supplied PortAudio error code into a human readable
108 message.
109 */
110 const char *Pa_GetErrorText( PaError errorCode );
111
112
113 /** Library initialization function - call this before using PortAudio.
114 This function initialises internal data structures and prepares underlying
115 host APIs for use. With the exception of Pa_GetVersion(), Pa_GetVersionText(),
116 and Pa_GetErrorText(), this function MUST be called before using any other
117 PortAudio API functions.
118
119 If Pa_Initialize() is called multiple times, each successful
120 call must be matched with a corresponding call to Pa_Terminate().
121 Pairs of calls to Pa_Initialize()/Pa_Terminate() may overlap, and are not
122 required to be fully nested.
123
124 Note that if Pa_Initialize() returns an error code, Pa_Terminate() should
125 NOT be called.
126
127 @return paNoError if successful, otherwise an error code indicating the cause
128 of failure.
129
130 @see Pa_Terminate
131 */
132 PaError Pa_Initialize( void );
133
134
135 /** Library termination function - call this when finished using PortAudio.
136 This function deallocates all resources allocated by PortAudio since it was
137 initializied by a call to Pa_Initialize(). In cases where Pa_Initialise() has
138 been called multiple times, each call must be matched with a corresponding call
139 to Pa_Terminate(). The final matching call to Pa_Terminate() will automatically
140 close any PortAudio streams that are still open.
141
142 Pa_Terminate() MUST be called before exiting a program which uses PortAudio.
143 Failure to do so may result in serious resource leaks, such as audio devices
144 not being available until the next reboot.
145
146 @return paNoError if successful, otherwise an error code indicating the cause
147 of failure.
148
149 @see Pa_Initialize
150 */
151 PaError Pa_Terminate( void );
152
153
154
155 /** The type used to refer to audio devices. Values of this type usually
156 range from 0 to (Pa_GetDeviceCount()-1), and may also take on the PaNoDevice
157 and paUseHostApiSpecificDeviceSpecification values.
158
159 @see Pa_GetDeviceCount, paNoDevice, paUseHostApiSpecificDeviceSpecification
160 */
161 typedef int PaDeviceIndex;
162
163
164 /** A special PaDeviceIndex value indicating that no device is available,
165 or should be used.
166
167 @see PaDeviceIndex
168 */
169 #define paNoDevice ((PaDeviceIndex)-1)
170
171
172 /** A special PaDeviceIndex value indicating that the device(s) to be used
173 are specified in the host api specific stream info structure.
174
175 @see PaDeviceIndex
176 */
177 #define paUseHostApiSpecificDeviceSpecification ((PaDeviceIndex)-2)
178
179
180 /* Host API enumeration mechanism */
181
182 /** The type used to enumerate to host APIs at runtime. Values of this type
183 range from 0 to (Pa_GetHostApiCount()-1).
184
185 @see Pa_GetHostApiCount
186 */
187 typedef int PaHostApiIndex;
188
189
190 /** Retrieve the number of available host APIs. Even if a host API is
191 available it may have no devices available.
192
193 @return A non-negative value indicating the number of available host APIs
194 or, a PaErrorCode (which are always negative) if PortAudio is not initialized
195 or an error is encountered.
196
197 @see PaHostApiIndex
198 */
199 PaHostApiIndex Pa_GetHostApiCount( void );
200
201
202 /** Retrieve the index of the default host API. The default host API will be
203 the lowest common denominator host API on the current platform and is
204 unlikely to provide the best performance.
205
206 @return A non-negative value ranging from 0 to (Pa_GetHostApiCount()-1)
207 indicating the default host API index or, a PaErrorCode (which are always
208 negative) if PortAudio is not initialized or an error is encountered.
209 */
210 PaHostApiIndex Pa_GetDefaultHostApi( void );
211
212
213 /** Unchanging unique identifiers for each supported host API. This type
214 is used in the PaHostApiInfo structure. The values are guaranteed to be
215 unique and to never change, thus allowing code to be written that
216 conditionally uses host API specific extensions.
217
218 New type ids will be allocated when support for a host API reaches
219 "public alpha" status, prior to that developers should use the
220 paInDevelopment type id.
221
222 @see PaHostApiInfo
223 */
224 typedef enum PaHostApiTypeId
225 {
226 paInDevelopment=0, /* use while developing support for a new host API */
227 paDirectSound=1,
228 paMME=2,
229 paASIO=3,
230 paSoundManager=4,
231 paCoreAudio=5,
232 paOSS=7,
233 paALSA=8,
234 paAL=9,
235 paBeOS=10,
236 paWDMKS=11,
237 paJACK=12,
238 paWASAPI=13,
239 paAudioScienceHPI=14
240 } PaHostApiTypeId;
241
242
243 /** A structure containing information about a particular host API. */
244
245 typedef struct PaHostApiInfo
246 {
247 /** this is struct version 1 */
248 int structVersion;
249 /** The well known unique identifier of this host API @see PaHostApiTypeId */
250 PaHostApiTypeId type;
251 /** A textual description of the host API for display on user interfaces. */
252 const char *name;
253
254 /** The number of devices belonging to this host API. This field may be
255 used in conjunction with Pa_HostApiDeviceIndexToDeviceIndex() to enumerate
256 all devices for this host API.
257 @see Pa_HostApiDeviceIndexToDeviceIndex
258 */
259 int deviceCount;
260
261 /** The default input device for this host API. The value will be a
262 device index ranging from 0 to (Pa_GetDeviceCount()-1), or paNoDevice
263 if no default input device is available.
264 */
265 PaDeviceIndex defaultInputDevice;
266
267 /** The default output device for this host API. The value will be a
268 device index ranging from 0 to (Pa_GetDeviceCount()-1), or paNoDevice
269 if no default output device is available.
270 */
271 PaDeviceIndex defaultOutputDevice;
272
273 } PaHostApiInfo;
274
275
276 /** Retrieve a pointer to a structure containing information about a specific
277 host Api.
278
279 @param hostApi A valid host API index ranging from 0 to (Pa_GetHostApiCount()-1)
280
281 @return A pointer to an immutable PaHostApiInfo structure describing
282 a specific host API. If the hostApi parameter is out of range or an error
283 is encountered, the function returns NULL.
284
285 The returned structure is owned by the PortAudio implementation and must not
286 be manipulated or freed. The pointer is only guaranteed to be valid between
287 calls to Pa_Initialize() and Pa_Terminate().
288 */
289 const PaHostApiInfo * Pa_GetHostApiInfo( PaHostApiIndex hostApi );
290
291
292 /** Convert a static host API unique identifier, into a runtime
293 host API index.
294
295 @param type A unique host API identifier belonging to the PaHostApiTypeId
296 enumeration.
297
298 @return A valid PaHostApiIndex ranging from 0 to (Pa_GetHostApiCount()-1) or,
299 a PaErrorCode (which are always negative) if PortAudio is not initialized
300 or an error is encountered.
301
302 The paHostApiNotFound error code indicates that the host API specified by the
303 type parameter is not available.
304
305 @see PaHostApiTypeId
306 */
307 PaHostApiIndex Pa_HostApiTypeIdToHostApiIndex( PaHostApiTypeId type );
308
309
310 /** Convert a host-API-specific device index to standard PortAudio device index.
311 This function may be used in conjunction with the deviceCount field of
312 PaHostApiInfo to enumerate all devices for the specified host API.
313
314 @param hostApi A valid host API index ranging from 0 to (Pa_GetHostApiCount()-1)
315
316 @param hostApiDeviceIndex A valid per-host device index in the range
317 0 to (Pa_GetHostApiInfo(hostApi)->deviceCount-1)
318
319 @return A non-negative PaDeviceIndex ranging from 0 to (Pa_GetDeviceCount()-1)
320 or, a PaErrorCode (which are always negative) if PortAudio is not initialized
321 or an error is encountered.
322
323 A paInvalidHostApi error code indicates that the host API index specified by
324 the hostApi parameter is out of range.
325
326 A paInvalidDevice error code indicates that the hostApiDeviceIndex parameter
327 is out of range.
328
329 @see PaHostApiInfo
330 */
331 PaDeviceIndex Pa_HostApiDeviceIndexToDeviceIndex( PaHostApiIndex hostApi,
332 int hostApiDeviceIndex );
333
334
335
336 /** Structure used to return information about a host error condition.
337 */
338 typedef struct PaHostErrorInfo{
339 PaHostApiTypeId hostApiType; /**< the host API which returned the error code */
340 long errorCode; /**< the error code returned */
341 const char *errorText; /**< a textual description of the error if available, otherwise a zero-length string */
342 }PaHostErrorInfo;
343
344
345 /** Return information about the last host error encountered. The error
346 information returned by Pa_GetLastHostErrorInfo() will never be modified
347 asyncronously by errors occurring in other PortAudio owned threads
348 (such as the thread that manages the stream callback.)
349
350 This function is provided as a last resort, primarily to enhance debugging
351 by providing clients with access to all available error information.
352
353 @return A pointer to an immutable structure constaining information about
354 the host error. The values in this structure will only be valid if a
355 PortAudio function has previously returned the paUnanticipatedHostError
356 error code.
357 */
358 const PaHostErrorInfo* Pa_GetLastHostErrorInfo( void );
359
360
361
362 /* Device enumeration and capabilities */
363
364 /** Retrieve the number of available devices. The number of available devices
365 may be zero.
366
367 @return A non-negative value indicating the number of available devices or,
368 a PaErrorCode (which are always negative) if PortAudio is not initialized
369 or an error is encountered.
370 */
371 PaDeviceIndex Pa_GetDeviceCount( void );
372
373
374 /** Retrieve the index of the default input device. The result can be
375 used in the inputDevice parameter to Pa_OpenStream().
376
377 @return The default input device index for the default host API, or paNoDevice
378 if no default input device is available or an error was encountered.
379 */
380 PaDeviceIndex Pa_GetDefaultInputDevice( void );
381
382
383 /** Retrieve the index of the default output device. The result can be
384 used in the outputDevice parameter to Pa_OpenStream().
385
386 @return The default output device index for the defualt host API, or paNoDevice
387 if no default output device is available or an error was encountered.
388
389 @note
390 On the PC, the user can specify a default device by
391 setting an environment variable. For example, to use device #1.
392 <pre>
393 set PA_RECOMMENDED_OUTPUT_DEVICE=1
394 </pre>
395 The user should first determine the available device ids by using
396 the supplied application "pa_devs".
397 */
398 PaDeviceIndex Pa_GetDefaultOutputDevice( void );
399
400
401 /** The type used to represent monotonic time in seconds that can be used
402 for syncronisation. The type is used for the outTime argument to the
403 PaStreamCallback and as the result of Pa_GetStreamTime().
404
405 @see PaStreamCallback, Pa_GetStreamTime
406 */
407 typedef double PaTime;
408
409
410 /** A type used to specify one or more sample formats. Each value indicates
411 a possible format for sound data passed to and from the stream callback,
412 Pa_ReadStream and Pa_WriteStream.
413
414 The standard formats paFloat32, paInt16, paInt32, paInt24, paInt8
415 and aUInt8 are usually implemented by all implementations.
416
417 The floating point representation (paFloat32) uses +1.0 and -1.0 as the
418 maximum and minimum respectively.
419
420 paUInt8 is an unsigned 8 bit format where 128 is considered "ground"
421
422 The paNonInterleaved flag indicates that a multichannel buffer is passed
423 as a set of non-interleaved pointers.
424
425 @see Pa_OpenStream, Pa_OpenDefaultStream, PaDeviceInfo
426 @see paFloat32, paInt16, paInt32, paInt24, paInt8
427 @see paUInt8, paCustomFormat, paNonInterleaved
428 */
429 typedef unsigned long PaSampleFormat;
430
431
432 #define paFloat32 ((PaSampleFormat) 0x00000001) /**< @see PaSampleFormat */
433 #define paInt32 ((PaSampleFormat) 0x00000002) /**< @see PaSampleFormat */
434 #define paInt24 ((PaSampleFormat) 0x00000004) /**< Packed 24 bit format. @see PaSampleFormat */
435 #define paInt16 ((PaSampleFormat) 0x00000008) /**< @see PaSampleFormat */
436 #define paInt8 ((PaSampleFormat) 0x00000010) /**< @see PaSampleFormat */
437 #define paUInt8 ((PaSampleFormat) 0x00000020) /**< @see PaSampleFormat */
438 #define paCustomFormat ((PaSampleFormat) 0x00010000)/**< @see PaSampleFormat */
439
440 #define paNonInterleaved ((PaSampleFormat) 0x80000000)
441
442 /** A structure providing information and capabilities of PortAudio devices.
443 Devices may support input, output or both input and output.
444 */
445 typedef struct PaDeviceInfo
446 {
447 int structVersion; /* this is struct version 2 */
448 const char *name;
449 PaHostApiIndex hostApi; /* note this is a host API index, not a type id*/
450
451 int maxInputChannels;
452 int maxOutputChannels;
453
454 /* Default latency values for interactive performance. */
455 PaTime defaultLowInputLatency;
456 PaTime defaultLowOutputLatency;
457 /* Default latency values for robust non-interactive applications (eg. playing sound files). */
458 PaTime defaultHighInputLatency;
459 PaTime defaultHighOutputLatency;
460
461 double defaultSampleRate;
462 } PaDeviceInfo;
463
464
465 /** Retrieve a pointer to a PaDeviceInfo structure containing information
466 about the specified device.
467 @return A pointer to an immutable PaDeviceInfo structure. If the device
468 parameter is out of range the function returns NULL.
469
470 @param device A valid device index in the range 0 to (Pa_GetDeviceCount()-1)
471
472 @note PortAudio manages the memory referenced by the returned pointer,
473 the client must not manipulate or free the memory. The pointer is only
474 guaranteed to be valid between calls to Pa_Initialize() and Pa_Terminate().
475
476 @see PaDeviceInfo, PaDeviceIndex
477 */
478 const PaDeviceInfo* Pa_GetDeviceInfo( PaDeviceIndex device );
479
480
481 /** Parameters for one direction (input or output) of a stream.
482 */
483 typedef struct PaStreamParameters
484 {
485 /** A valid device index in the range 0 to (Pa_GetDeviceCount()-1)
486 specifying the device to be used or the special constant
487 paUseHostApiSpecificDeviceSpecification which indicates that the actual
488 device(s) to use are specified in hostApiSpecificStreamInfo.
489 This field must not be set to paNoDevice.
490 */
491 PaDeviceIndex device;
492
493 /** The number of channels of sound to be delivered to the
494 stream callback or accessed by Pa_ReadStream() or Pa_WriteStream().
495 It can range from 1 to the value of maxInputChannels in the
496 PaDeviceInfo record for the device specified by the device parameter.
497 */
498 int channelCount;
499
500 /** The sample format of the buffer provided to the stream callback,
501 a_ReadStream() or Pa_WriteStream(). It may be any of the formats described
502 by the PaSampleFormat enumeration.
503 */
504 PaSampleFormat sampleFormat;
505
506 /** The desired latency in seconds. Where practical, implementations should
507 configure their latency based on these parameters, otherwise they may
508 choose the closest viable latency instead. Unless the suggested latency
509 is greater than the absolute upper limit for the device implementations
510 should round the suggestedLatency up to the next practial value - ie to
511 provide an equal or higher latency than suggestedLatency wherever possibe.
512 Actual latency values for an open stream may be retrieved using the
513 inputLatency and outputLatency fields of the PaStreamInfo structure
514 returned by Pa_GetStreamInfo().
515 @see default*Latency in PaDeviceInfo, *Latency in PaStreamInfo
516 */
517 PaTime suggestedLatency;
518
519 /** An optional pointer to a host api specific data structure
520 containing additional information for device setup and/or stream processing.
521 hostApiSpecificStreamInfo is never required for correct operation,
522 if not used it should be set to NULL.
523 */
524 void *hostApiSpecificStreamInfo;
525
526 } PaStreamParameters;
527
528
529 /** Return code for Pa_IsFormatSupported indicating success. */
530 #define paFormatIsSupported (0)
531
532 /** Determine whether it would be possible to open a stream with the specified
533 parameters.
534
535 @param inputParameters A structure that describes the input parameters used to
536 open a stream. The suggestedLatency field is ignored. See PaStreamParameters
537 for a description of these parameters. inputParameters must be NULL for
538 output-only streams.
539
540 @param outputParameters A structure that describes the output parameters used
541 to open a stream. The suggestedLatency field is ignored. See PaStreamParameters
542 for a description of these parameters. outputParameters must be NULL for
543 input-only streams.
544
545 @param sampleRate The required sampleRate. For full-duplex streams it is the
546 sample rate for both input and output
547
548 @return Returns 0 if the format is supported, and an error code indicating why
549 the format is not supported otherwise. The constant paFormatIsSupported is
550 provided to compare with the return value for success.
551
552 @see paFormatIsSupported, PaStreamParameters
553 */
554 PaError Pa_IsFormatSupported( const PaStreamParameters *inputParameters,
555 const PaStreamParameters *outputParameters,
556 double sampleRate );
557
558
559
560 /* Streaming types and functions */
561
562
563 /**
564 A single PaStream can provide multiple channels of real-time
565 streaming audio input and output to a client application. A stream
566 provides access to audio hardware represented by one or more
567 PaDevices. Depending on the underlying Host API, it may be possible
568 to open multiple streams using the same device, however this behavior
569 is implementation defined. Portable applications should assume that
570 a PaDevice may be simultaneously used by at most one PaStream.
571
572 Pointers to PaStream objects are passed between PortAudio functions that
573 operate on streams.
574
575 @see Pa_OpenStream, Pa_OpenDefaultStream, Pa_OpenDefaultStream, Pa_CloseStream,
576 Pa_StartStream, Pa_StopStream, Pa_AbortStream, Pa_IsStreamActive,
577 Pa_GetStreamTime, Pa_GetStreamCpuLoad
578
579 */
580 typedef void PaStream;
581
582
583 /** Can be passed as the framesPerBuffer parameter to Pa_OpenStream()
584 or Pa_OpenDefaultStream() to indicate that the stream callback will
585 accept buffers of any size.
586 */
587 #define paFramesPerBufferUnspecified (0)
588
589
590 /** Flags used to control the behavior of a stream. They are passed as
591 parameters to Pa_OpenStream or Pa_OpenDefaultStream. Multiple flags may be
592 ORed together.
593
594 @see Pa_OpenStream, Pa_OpenDefaultStream
595 @see paNoFlag, paClipOff, paDitherOff, paNeverDropInput,
596 paPrimeOutputBuffersUsingStreamCallback, paPlatformSpecificFlags
597 */
598 typedef unsigned long PaStreamFlags;
599
600 /** @see PaStreamFlags */
601 #define paNoFlag ((PaStreamFlags) 0)
602
603 /** Disable default clipping of out of range samples.
604 @see PaStreamFlags
605 */
606 #define paClipOff ((PaStreamFlags) 0x00000001)
607
608 /** Disable default dithering.
609 @see PaStreamFlags
610 */
611 #define paDitherOff ((PaStreamFlags) 0x00000002)
612
613 /** Flag requests that where possible a full duplex stream will not discard
614 overflowed input samples without calling the stream callback. This flag is
615 only valid for full duplex callback streams and only when used in combination
616 with the paFramesPerBufferUnspecified (0) framesPerBuffer parameter. Using
617 this flag incorrectly results in a paInvalidFlag error being returned from
618 Pa_OpenStream and Pa_OpenDefaultStream.
619
620 @see PaStreamFlags, paFramesPerBufferUnspecified
621 */
622 #define paNeverDropInput ((PaStreamFlags) 0x00000004)
623
624 /** Call the stream callback to fill initial output buffers, rather than the
625 default behavior of priming the buffers with zeros (silence). This flag has
626 no effect for input-only and blocking read/write streams.
627
628 @see PaStreamFlags
629 */
630 #define paPrimeOutputBuffersUsingStreamCallback ((PaStreamFlags) 0x00000008)
631
632 /** A mask specifying the platform specific bits.
633 @see PaStreamFlags
634 */
635 #define paPlatformSpecificFlags ((PaStreamFlags)0xFFFF0000)
636
637 /**
638 Timing information for the buffers passed to the stream callback.
639 */
640 typedef struct PaStreamCallbackTimeInfo{
641 PaTime inputBufferAdcTime;
642 PaTime currentTime;
643 PaTime outputBufferDacTime;
644 } PaStreamCallbackTimeInfo;
645
646
647 /**
648 Flag bit constants for the statusFlags to PaStreamCallback.
649
650 @see paInputUnderflow, paInputOverflow, paOutputUnderflow, paOutputOverflow,
651 paPrimingOutput
652 */
653 typedef unsigned long PaStreamCallbackFlags;
654
655 /** In a stream opened with paFramesPerBufferUnspecified, indicates that
656 input data is all silence (zeros) because no real data is available. In a
657 stream opened without paFramesPerBufferUnspecified, it indicates that one or
658 more zero samples have been inserted into the input buffer to compensate
659 for an input underflow.
660 @see PaStreamCallbackFlags
661 */
662 #define paInputUnderflow ((PaStreamCallbackFlags) 0x00000001)
663
664 /** In a stream opened with paFramesPerBufferUnspecified, indicates that data
665 prior to the first sample of the input buffer was discarded due to an
666 overflow, possibly because the stream callback is using too much CPU time.
667 Otherwise indicates that data prior to one or more samples in the
668 input buffer was discarded.
669 @see PaStreamCallbackFlags
670 */
671 #define paInputOverflow ((PaStreamCallbackFlags) 0x00000002)
672
673 /** Indicates that output data (or a gap) was inserted, possibly because the
674 stream callback is using too much CPU time.
675 @see PaStreamCallbackFlags
676 */
677 #define paOutputUnderflow ((PaStreamCallbackFlags) 0x00000004)
678
679 /** Indicates that output data will be discarded because no room is available.
680 @see PaStreamCallbackFlags
681 */
682 #define paOutputOverflow ((PaStreamCallbackFlags) 0x00000008)
683
684 /** Some of all of the output data will be used to prime the stream, input
685 data may be zero.
686 @see PaStreamCallbackFlags
687 */
688 #define paPrimingOutput ((PaStreamCallbackFlags) 0x00000010)
689
690 /**
691 Allowable return values for the PaStreamCallback.
692 @see PaStreamCallback
693 */
694 typedef enum PaStreamCallbackResult
695 {
696 paContinue=0,
697 paComplete=1,
698 paAbort=2
699 } PaStreamCallbackResult;
700
701
702 /**
703 Functions of type PaStreamCallback are implemented by PortAudio clients.
704 They consume, process or generate audio in response to requests from an
705 active PortAudio stream.
706
707 @param input and @param output are arrays of interleaved samples,
708 the format, packing and number of channels used by the buffers are
709 determined by parameters to Pa_OpenStream().
710
711 @param frameCount The number of sample frames to be processed by
712 the stream callback.
713
714 @param timeInfo The time in seconds when the first sample of the input
715 buffer was received at the audio input, the time in seconds when the first
716 sample of the output buffer will begin being played at the audio output, and
717 the time in seconds when the stream callback was called.
718 See also Pa_GetStreamTime()
719
720 @param statusFlags Flags indicating whether input and/or output buffers
721 have been inserted or will be dropped to overcome underflow or overflow
722 conditions.
723
724 @param userData The value of a user supplied pointer passed to
725 Pa_OpenStream() intended for storing synthesis data etc.
726
727 @return
728 The stream callback should return one of the values in the
729 PaStreamCallbackResult enumeration. To ensure that the callback continues
730 to be called, it should return paContinue (0). Either paComplete or paAbort
731 can be returned to finish stream processing, after either of these values is
732 returned the callback will not be called again. If paAbort is returned the
733 stream will finish as soon as possible. If paComplete is returned, the stream
734 will continue until all buffers generated by the callback have been played.
735 This may be useful in applications such as soundfile players where a specific
736 duration of output is required. However, it is not necessary to utilise this
737 mechanism as Pa_StopStream(), Pa_AbortStream() or Pa_CloseStream() can also
738 be used to stop the stream. The callback must always fill the entire output
739 buffer irrespective of its return value.
740
741 @see Pa_OpenStream, Pa_OpenDefaultStream
742
743 @note With the exception of Pa_GetStreamCpuLoad() it is not permissable to call
744 PortAudio API functions from within the stream callback.
745 */
746 typedef int PaStreamCallback(
747 const void *input, void *output,
748 unsigned long frameCount,
749 const PaStreamCallbackTimeInfo* timeInfo,
750 PaStreamCallbackFlags statusFlags,
751 void *userData );
752
753
754 /** Opens a stream for either input, output or both.
755
756 @param stream The address of a PaStream pointer which will receive
757 a pointer to the newly opened stream.
758
759 @param inputParameters A structure that describes the input parameters used by
760 the opened stream. See PaStreamParameters for a description of these parameters.
761 inputParameters must be NULL for output-only streams.
762
763 @param outputParameters A structure that describes the output parameters used by
764 the opened stream. See PaStreamParameters for a description of these parameters.
765 outputParameters must be NULL for input-only streams.
766
767 @param sampleRate The desired sampleRate. For full-duplex streams it is the
768 sample rate for both input and output
769
770 @param framesPerBuffer The number of frames passed to the stream callback
771 function, or the preferred block granularity for a blocking read/write stream.
772 The special value paFramesPerBufferUnspecified (0) may be used to request that
773 the stream callback will recieve an optimal (and possibly varying) number of
774 frames based on host requirements and the requested latency settings.
775 Note: With some host APIs, the use of non-zero framesPerBuffer for a callback
776 stream may introduce an additional layer of buffering which could introduce
777 additional latency. PortAudio guarantees that the additional latency
778 will be kept to the theoretical minimum however, it is strongly recommended
779 that a non-zero framesPerBuffer value only be used when your algorithm
780 requires a fixed number of frames per stream callback.
781
782 @param streamFlags Flags which modify the behaviour of the streaming process.
783 This parameter may contain a combination of flags ORed together. Some flags may
784 only be relevant to certain buffer formats.
785
786 @param streamCallback A pointer to a client supplied function that is responsible
787 for processing and filling input and output buffers. If this parameter is NULL
788 the stream will be opened in 'blocking read/write' mode. In blocking mode,
789 the client can receive sample data using Pa_ReadStream and write sample data
790 using Pa_WriteStream, the number of samples that may be read or written
791 without blocking is returned by Pa_GetStreamReadAvailable and
792 Pa_GetStreamWriteAvailable respectively.
793
794 @param userData A client supplied pointer which is passed to the stream callback
795 function. It could for example, contain a pointer to instance data necessary
796 for processing the audio buffers. This parameter is ignored if streamCallback
797 is NULL.
798
799 @return
800 Upon success Pa_OpenStream() returns paNoError and places a pointer to a
801 valid PaStream in the stream argument. The stream is inactive (stopped).
802 If a call to Pa_OpenStream() fails, a non-zero error code is returned (see
803 PaError for possible error codes) and the value of stream is invalid.
804
805 @see PaStreamParameters, PaStreamCallback, Pa_ReadStream, Pa_WriteStream,
806 Pa_GetStreamReadAvailable, Pa_GetStreamWriteAvailable
807 */
808 PaError Pa_OpenStream( PaStream** stream,
809 const PaStreamParameters *inputParameters,
810 const PaStreamParameters *outputParameters,
811 double sampleRate,
812 unsigned long framesPerBuffer,
813 PaStreamFlags streamFlags,
814 PaStreamCallback *streamCallback,
815 void *userData );
816
817
818 /** A simplified version of Pa_OpenStream() that opens the default input
819 and/or output devices.
820
821 @param stream The address of a PaStream pointer which will receive
822 a pointer to the newly opened stream.
823
824 @param numInputChannels The number of channels of sound that will be supplied
825 to the stream callback or returned by Pa_ReadStream. It can range from 1 to
826 the value of maxInputChannels in the PaDeviceInfo record for the default input
827 device. If 0 the stream is opened as an output-only stream.
828
829 @param numOutputChannels The number of channels of sound to be delivered to the
830 stream callback or passed to Pa_WriteStream. It can range from 1 to the value
831 of maxOutputChannels in the PaDeviceInfo record for the default output dvice.
832 If 0 the stream is opened as an output-only stream.
833
834 @param sampleFormat The sample format of both the input and output buffers
835 provided to the callback or passed to and from Pa_ReadStream and Pa_WriteStream.
836 sampleFormat may be any of the formats described by the PaSampleFormat
837 enumeration.
838
839 @param sampleRate Same as Pa_OpenStream parameter of the same name.
840 @param framesPerBuffer Same as Pa_OpenStream parameter of the same name.
841 @param streamCallback Same as Pa_OpenStream parameter of the same name.
842 @param userData Same as Pa_OpenStream parameter of the same name.
843
844 @return As for Pa_OpenStream
845
846 @see Pa_OpenStream, PaStreamCallback
847 */
848 PaError Pa_OpenDefaultStream( PaStream** stream,
849 int numInputChannels,
850 int numOutputChannels,
851 PaSampleFormat sampleFormat,
852 double sampleRate,
853 unsigned long framesPerBuffer,
854 PaStreamCallback *streamCallback,
855 void *userData );
856
857
858 /** Closes an audio stream. If the audio stream is active it
859 discards any pending buffers as if Pa_AbortStream() had been called.
860 */
861 PaError Pa_CloseStream( PaStream *stream );
862
863
864 /** Functions of type PaStreamFinishedCallback are implemented by PortAudio
865 clients. They can be registered with a stream using the Pa_SetStreamFinishedCallback
866 function. Once registered they are called when the stream becomes inactive
867 (ie once a call to Pa_StopStream() will not block).
868 A stream will become inactive after the stream callback returns non-zero,
869 or when Pa_StopStream or Pa_AbortStream is called. For a stream providing audio
870 output, if the stream callback returns paComplete, or Pa_StopStream is called,
871 the stream finished callback will not be called until all generated sample data
872 has been played.
873
874 @param userData The userData parameter supplied to Pa_OpenStream()
875
876 @see Pa_SetStreamFinishedCallback
877 */
878 typedef void PaStreamFinishedCallback( void *userData );
879
880
881 /** Register a stream finished callback function which will be called when the
882 stream becomes inactive. See the description of PaStreamFinishedCallback for
883 further details about when the callback will be called.
884
885 @param stream a pointer to a PaStream that is in the stopped state - if the
886 stream is not stopped, the stream's finished callback will remain unchanged
887 and an error code will be returned.
888
889 @param streamFinishedCallback a pointer to a function with the same signature
890 as PaStreamFinishedCallback, that will be called when the stream becomes
891 inactive. Passing NULL for this parameter will un-register a previously
892 registered stream finished callback function.
893
894 @return on success returns paNoError, otherwise an error code indicating the cause
895 of the error.
896
897 @see PaStreamFinishedCallback
898 */
899 PaError Pa_SetStreamFinishedCallback( PaStream *stream, PaStreamFinishedCallback* streamFinishedCallback );
900
901
902 /** Commences audio processing.
903 */
904 PaError Pa_StartStream( PaStream *stream );
905
906
907 /** Terminates audio processing. It waits until all pending
908 audio buffers have been played before it returns.
909 */
910 PaError Pa_StopStream( PaStream *stream );
911
912
913 /** Terminates audio processing immediately without waiting for pending
914 buffers to complete.
915 */
916 PaError Pa_AbortStream( PaStream *stream );
917
918
919 /** Determine whether the stream is stopped.
920 A stream is considered to be stopped prior to a successful call to
921 Pa_StartStream and after a successful call to Pa_StopStream or Pa_AbortStream.
922 If a stream callback returns a value other than paContinue the stream is NOT
923 considered to be stopped.
924
925 @return Returns one (1) when the stream is stopped, zero (0) when
926 the stream is running or, a PaErrorCode (which are always negative) if
927 PortAudio is not initialized or an error is encountered.
928
929 @see Pa_StopStream, Pa_AbortStream, Pa_IsStreamActive
930 */
931 PaError Pa_IsStreamStopped( PaStream *stream );
932
933
934 /** Determine whether the stream is active.
935 A stream is active after a successful call to Pa_StartStream(), until it
936 becomes inactive either as a result of a call to Pa_StopStream() or
937 Pa_AbortStream(), or as a result of a return value other than paContinue from
938 the stream callback. In the latter case, the stream is considered inactive
939 after the last buffer has finished playing.
940
941 @return Returns one (1) when the stream is active (ie playing or recording
942 audio), zero (0) when not playing or, a PaErrorCode (which are always negative)
943 if PortAudio is not initialized or an error is encountered.
944
945 @see Pa_StopStream, Pa_AbortStream, Pa_IsStreamStopped
946 */
947 PaError Pa_IsStreamActive( PaStream *stream );
948
949
950
951 /** A structure containing unchanging information about an open stream.
952 @see Pa_GetStreamInfo
953 */
954
955 typedef struct PaStreamInfo
956 {
957 /** this is struct version 1 */
958 int structVersion;
959
960 /** The input latency of the stream in seconds. This value provides the most
961 accurate estimate of input latency available to the implementation. It may
962 differ significantly from the suggestedLatency value passed to Pa_OpenStream().
963 The value of this field will be zero (0.) for output-only streams.
964 @see PaTime
965 */
966 PaTime inputLatency;
967
968 /** The output latency of the stream in seconds. This value provides the most
969 accurate estimate of output latency available to the implementation. It may
970 differ significantly from the suggestedLatency value passed to Pa_OpenStream().
971 The value of this field will be zero (0.) for input-only streams.
972 @see PaTime
973 */
974 PaTime outputLatency;
975
976 /** The sample rate of the stream in Hertz (samples per second). In cases
977 where the hardware sample rate is inaccurate and PortAudio is aware of it,
978 the value of this field may be different from the sampleRate parameter
979 passed to Pa_OpenStream(). If information about the actual hardware sample
980 rate is not available, this field will have the same value as the sampleRate
981 parameter passed to Pa_OpenStream().
982 */
983 double sampleRate;
984
985 } PaStreamInfo;
986
987
988 /** Retrieve a pointer to a PaStreamInfo structure containing information
989 about the specified stream.
990 @return A pointer to an immutable PaStreamInfo structure. If the stream
991 parameter invalid, or an error is encountered, the function returns NULL.
992
993 @param stream A pointer to an open stream previously created with Pa_OpenStream.
994
995 @note PortAudio manages the memory referenced by the returned pointer,
996 the client must not manipulate or free the memory. The pointer is only
997 guaranteed to be valid until the specified stream is closed.
998
999 @see PaStreamInfo
1000 */
1001 const PaStreamInfo* Pa_GetStreamInfo( PaStream *stream );
1002
1003
1004 /** Determine the current time for the stream according to the same clock used
1005 to generate buffer timestamps. This time may be used for syncronising other
1006 events to the audio stream, for example synchronizing audio to MIDI.
1007
1008 @return The stream's current time in seconds, or 0 if an error occurred.
1009
1010 @see PaTime, PaStreamCallback
1011 */
1012 PaTime Pa_GetStreamTime( PaStream *stream );
1013
1014
1015 /** Retrieve CPU usage information for the specified stream.
1016 The "CPU Load" is a fraction of total CPU time consumed by a callback stream's
1017 audio processing routines including, but not limited to the client supplied
1018 stream callback. This function does not work with blocking read/write streams.
1019
1020 This function may be called from the stream callback function or the
1021 application.
1022
1023 @return
1024 A floating point value, typically between 0.0 and 1.0, where 1.0 indicates
1025 that the stream callback is consuming the maximum number of CPU cycles possible
1026 to maintain real-time operation. A value of 0.5 would imply that PortAudio and
1027 the stream callback was consuming roughly 50% of the available CPU time. The
1028 return value may exceed 1.0. A value of 0.0 will always be returned for a
1029 blocking read/write stream, or if an error occurrs.
1030 */
1031 double Pa_GetStreamCpuLoad( PaStream* stream );
1032
1033
1034 /** Read samples from an input stream. The function doesn't return until
1035 the entire buffer has been filled - this may involve waiting for the operating
1036 system to supply the data.
1037
1038 @param stream A pointer to an open stream previously created with Pa_OpenStream.
1039
1040 @param buffer A pointer to a buffer of sample frames. The buffer contains
1041 samples in the format specified by the inputParameters->sampleFormat field
1042 used to open the stream, and the number of channels specified by
1043 inputParameters->numChannels. If non-interleaved samples were requested,
1044 buffer is a pointer to the first element of an array of non-interleaved
1045 buffer pointers, one for each channel.
1046
1047 @param frames The number of frames to be read into buffer. This parameter
1048 is not constrained to a specific range, however high performance applications
1049 will want to match this parameter to the framesPerBuffer parameter used
1050 when opening the stream.
1051
1052 @return On success PaNoError will be returned, or PaInputOverflowed if input
1053 data was discarded by PortAudio after the previous call and before this call.
1054 */
1055 PaError Pa_ReadStream( PaStream* stream,
1056 void *buffer,
1057 unsigned long frames );
1058
1059
1060 /** Write samples to an output stream. This function doesn't return until the
1061 entire buffer has been consumed - this may involve waiting for the operating
1062 system to consume the data.
1063
1064 @param stream A pointer to an open stream previously created with Pa_OpenStream.
1065
1066 @param buffer A pointer to a buffer of sample frames. The buffer contains
1067 samples in the format specified by the outputParameters->sampleFormat field
1068 used to open the stream, and the number of channels specified by
1069 outputParameters->numChannels. If non-interleaved samples were requested,
1070 buffer is a pointer to the first element of an array of non-interleaved
1071 buffer pointers, one for each channel.
1072
1073 @param frames The number of frames to be written from buffer. This parameter
1074 is not constrained to a specific range, however high performance applications
1075 will want to match this parameter to the framesPerBuffer parameter used
1076 when opening the stream.
1077
1078 @return On success PaNoError will be returned, or paOutputUnderflowed if
1079 additional output data was inserted after the previous call and before this
1080 call.
1081 */
1082 PaError Pa_WriteStream( PaStream* stream,
1083 const void *buffer,
1084 unsigned long frames );
1085
1086
1087 /** Retrieve the number of frames that can be read from the stream without
1088 waiting.
1089
1090 @return Returns a non-negative value representing the maximum number of frames
1091 that can be read from the stream without blocking or busy waiting or, a
1092 PaErrorCode (which are always negative) if PortAudio is not initialized or an
1093 error is encountered.
1094 */
1095 signed long Pa_GetStreamReadAvailable( PaStream* stream );
1096
1097
1098 /** Retrieve the number of frames that can be written to the stream without
1099 waiting.
1100
1101 @return Returns a non-negative value representing the maximum number of frames
1102 that can be written to the stream without blocking or busy waiting or, a
1103 PaErrorCode (which are always negative) if PortAudio is not initialized or an
1104 error is encountered.
1105 */
1106 signed long Pa_GetStreamWriteAvailable( PaStream* stream );
1107
1108
1109 /* Miscellaneous utilities */
1110
1111
1112 /** Retrieve the size of a given sample format in bytes.
1113
1114 @return The size in bytes of a single sample in the specified format,
1115 or paSampleFormatNotSupported if the format is not supported.
1116 */
1117 PaError Pa_GetSampleSize( PaSampleFormat format );
1118
1119
1120 /** Put the caller to sleep for at least 'msec' milliseconds. This function is
1121 provided only as a convenience for authors of portable code (such as the tests
1122 and examples in the PortAudio distribution.)
1123
1124 The function may sleep longer than requested so don't rely on this for accurate
1125 musical timing.
1126 */
1127 void Pa_Sleep( long msec );
1128
1129
1130
1131 #ifdef __cplusplus
1132 }
1133 #endif /* __cplusplus */
1134 #endif /* PORTAUDIO_H */

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