1#ifndef foostreamhfoo
2#define foostreamhfoo
3
4/***
5 This file is part of PulseAudio.
6
7 Copyright 2004-2006 Lennart Poettering
8 Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
9
10 PulseAudio is free software; you can redistribute it and/or modify
11 it under the terms of the GNU Lesser General Public License as published
12 by the Free Software Foundation; either version 2.1 of the License,
13 or (at your option) any later version.
14
15 PulseAudio is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 General Public License for more details.
19
20 You should have received a copy of the GNU Lesser General Public License
21 along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
22***/
23
24#include <sys/types.h>
25
26#include <pulse/sample.h>
27#include <pulse/format.h>
28#include <pulse/channelmap.h>
29#include <pulse/volume.h>
30#include <pulse/def.h>
31#include <pulse/cdecl.h>
32#include <pulse/operation.h>
33#include <pulse/context.h>
34#include <pulse/proplist.h>
35
36/** \page streams Audio Streams
37 *
38 * \section overv_sec Overview
39 *
40 * Audio streams form the central functionality of the sound server. Data is
41 * routed, converted and mixed from several sources before it is passed along
42 * to a final output. Currently, there are three forms of audio streams:
43 *
44 * \li Playback streams - Data flows from the client to the server.
45 * \li Record streams - Data flows from the server to the client.
46 * \li Upload streams - Similar to playback streams, but the data is stored in
47 * the sample cache. See \ref scache for more information
48 * about controlling the sample cache.
49 *
50 * \section create_sec Creating
51 *
52 * To access a stream, a pa_stream object must be created using
53 * pa_stream_new() or pa_stream_new_extended(). pa_stream_new() is for PCM
54 * streams only, while pa_stream_new_extended() can be used for both PCM and
55 * compressed audio streams. At this point the application must specify what
56 * stream format(s) it supports. See \ref sample and \ref channelmap for more
57 * information on the stream format parameters. FIXME: Those references only
58 * talk about PCM parameters, we should also have an overview page for how the
59 * pa_format_info based stream format configuration works. Bug filed:
60 * https://bugs.freedesktop.org/show_bug.cgi?id=72265
61 *
62 * This first step will only create a client-side object, representing the
63 * stream. To use the stream, a server-side object must be created and
64 * associated with the local object. Depending on which type of stream is
65 * desired, a different function is needed:
66 *
67 * \li Playback stream - pa_stream_connect_playback()
68 * \li Record stream - pa_stream_connect_record()
69 * \li Upload stream - pa_stream_connect_upload() (see \ref scache)
70 *
71 * Similar to how connections are done in contexts, connecting a stream will
72 * not generate a pa_operation object. Also like contexts, the application
73 * should register a state change callback, using
74 * pa_stream_set_state_callback(), and wait for the stream to enter an active
75 * state.
76 *
77 * Note: there is a user-controllable slider in mixer applications such as
78 * pavucontrol corresponding to each of the created streams. Multiple
79 * (especially identically named) volume sliders for the same application might
80 * confuse the user. Also, the server supports only a limited number of
81 * simultaneous streams. Because of this, it is not always appropriate to
82 * create multiple streams in one application that needs to output multiple
83 * sounds. The rough guideline is: if there is no use case that would require
84 * separate user-initiated volume changes for each stream, perform the mixing
85 * inside the application.
86 *
87 * \subsection bufattr_subsec Buffer Attributes
88 *
89 * Playback and record streams always have a server-side buffer as
90 * part of the data flow. The size of this buffer needs to be chosen
91 * in a compromise between low latency and sensitivity for buffer
92 * overflows/underruns.
93 *
94 * The buffer metrics may be controlled by the application. They are
95 * described with a pa_buffer_attr structure.
96 *
97 * If PA_STREAM_ADJUST_LATENCY is set, then the tlength/fragsize
98 * parameters of the pa_buffer_attr structure will be interpreted
99 * slightly differently than otherwise when passed to
100 * pa_stream_connect_record() and pa_stream_connect_playback(): the
101 * overall latency that is comprised of both the server side playback
102 * buffer length, the hardware playback buffer length and additional
103 * latencies will be adjusted in a way that it matches tlength resp.
104 * fragsize. Set PA_STREAM_ADJUST_LATENCY if you want to control the
105 * overall playback latency for your stream. Unset it if you want to
106 * control only the latency induced by the server-side, rewritable
107 * playback buffer. The server will try to fulfill the client's latency
108 * requests as good as possible. However if the underlying hardware cannot
109 * change the hardware buffer length or only in a limited range, the
110 * actually resulting latency might be different from what the client
111 * requested. Thus, for synchronization clients always need to check
112 * the actual measured latency via pa_stream_get_latency() or a
113 * similar call, and not make any assumptions about the latency
114 * available. The function pa_stream_get_buffer_attr() will always
115 * return the actual size of the server-side per-stream buffer in
116 * tlength/fragsize, regardless whether PA_STREAM_ADJUST_LATENCY is
117 * set or not.
118 *
119 * The server-side per-stream playback buffers are indexed by a write and
120 * a read index. The application writes to the write index and the sound
121 * device reads from the read index. The read index is increased
122 * monotonically, while the write index may be freely controlled by
123 * the application. Subtracting the read index from the write index
124 * will give you the current fill level of the buffer. The read/write
125 * indexes are 64bit values and measured in bytes, they will never
126 * wrap. The current read/write index may be queried using
127 * pa_stream_get_timing_info() (see below for more information). In
128 * case of a buffer underrun the read index is equal or larger than
129 * the write index. Unless the prebuf value is 0, PulseAudio will
130 * temporarily pause playback in such a case, and wait until the
131 * buffer is filled up to prebuf bytes again. If prebuf is 0, the
132 * read index may be larger than the write index, in which case
133 * silence is played. If the application writes data to indexes lower
134 * than the read index, the data is immediately lost.
135 *
136 * \section transfer_sec Transferring Data
137 *
138 * Once the stream is up, data can start flowing between the client and the
139 * server. Two different access models can be used to transfer the data:
140 *
141 * \li Asynchronous - The application registers a callback using
142 * pa_stream_set_write_callback() and
143 * pa_stream_set_read_callback() to receive notifications
144 * that data can either be written or read.
145 * \li Polled - Query the library for available data/space using
146 * pa_stream_writable_size() and pa_stream_readable_size() and
147 * transfer data as needed. The sizes are stored locally, in the
148 * client end, so there is no delay when reading them.
149 *
150 * It is also possible to mix the two models freely.
151 *
152 * Once there is data/space available, it can be transferred using either
153 * pa_stream_write() for playback, or pa_stream_peek() / pa_stream_drop() for
154 * record. Make sure you do not overflow the playback buffers as data will be
155 * dropped.
156 *
157 * \section bufctl_sec Buffer Control
158 *
159 * The transfer buffers can be controlled through a number of operations:
160 *
161 * \li pa_stream_cork() - Start or stop the playback or recording.
162 * \li pa_stream_trigger() - Start playback immediately and do not wait for
163 * the buffer to fill up to the set trigger level.
164 * \li pa_stream_prebuf() - Reenable the playback trigger level.
165 * \li pa_stream_drain() - Wait for the playback buffer to go empty. Will
166 * return a pa_operation object that will indicate when
167 * the buffer is completely drained.
168 * \li pa_stream_flush() - Drop all data from the playback or record buffer. Do not
169 * wait for it to finish playing.
170 *
171 * \section seek_modes Seeking in the Playback Buffer
172 *
173 * A client application may freely seek in the playback buffer. To
174 * accomplish that the pa_stream_write() function takes a seek mode
175 * and an offset argument. The seek mode is one of:
176 *
177 * \li PA_SEEK_RELATIVE - seek relative to the current write index.
178 * \li PA_SEEK_ABSOLUTE - seek relative to the beginning of the playback buffer,
179 * (i.e. the first that was ever played in the stream).
180 * \li PA_SEEK_RELATIVE_ON_READ - seek relative to the current read index. Use
181 * this to write data to the output buffer that should be played as soon as possible.
182 * \li PA_SEEK_RELATIVE_END - seek relative to the last byte ever written.
183 *
184 * If an application just wants to append some data to the output
185 * buffer, PA_SEEK_RELATIVE and an offset of 0 should be used.
186 *
187 * After a call to pa_stream_write() the write index will be left at
188 * the position right after the last byte of the written data.
189 *
190 * \section latency_sec Latency
191 *
192 * A major problem with networked audio is the increased latency caused by
193 * the network. To remedy this, PulseAudio supports an advanced system of
194 * monitoring the current latency.
195 *
196 * To get the raw data needed to calculate latencies, call
197 * pa_stream_get_timing_info(). This will give you a pa_timing_info
198 * structure that contains everything that is known about the server
199 * side buffer transport delays and the backend active in the
200 * server. (Besides other things it contains the write and read index
201 * values mentioned above.)
202 *
203 * This structure is updated every time a
204 * pa_stream_update_timing_info() operation is executed. (i.e. before
205 * the first call to this function the timing information structure is
206 * not available!) Since it is a lot of work to keep this structure
207 * up-to-date manually, PulseAudio can do that automatically for you:
208 * if PA_STREAM_AUTO_TIMING_UPDATE is passed when connecting the
209 * stream PulseAudio will automatically update the structure every
210 * 100ms and every time a function is called that might invalidate the
211 * previously known timing data (such as pa_stream_write() or
212 * pa_stream_flush()). Please note however, that there always is a
213 * short time window when the data in the timing information structure
214 * is out-of-date. PulseAudio tries to mark these situations by
215 * setting the write_index_corrupt and read_index_corrupt fields
216 * accordingly.
217 *
218 * The raw timing data in the pa_timing_info structure is usually hard
219 * to deal with. Therefore a simpler interface is available:
220 * you can call pa_stream_get_time() or pa_stream_get_latency(). The
221 * former will return the current playback time of the hardware since
222 * the stream has been started. The latter returns the overall time a sample
223 * that you write now takes to be played by the hardware. These two
224 * functions base their calculations on the same data that is returned
225 * by pa_stream_get_timing_info(). Hence the same rules for keeping
226 * the timing data up-to-date apply here. In case the write or read
227 * index is corrupted, these two functions will fail with
228 * -PA_ERR_NODATA set.
229 *
230 * Since updating the timing info structure usually requires a full
231 * network round trip and some applications monitor the timing very
232 * often PulseAudio offers a timing interpolation system. If
233 * PA_STREAM_INTERPOLATE_TIMING is passed when connecting the stream,
234 * pa_stream_get_time() and pa_stream_get_latency() will try to
235 * interpolate the current playback time/latency by estimating the
236 * number of samples that have been played back by the hardware since
237 * the last regular timing update. It is especially useful to combine
238 * this option with PA_STREAM_AUTO_TIMING_UPDATE, which will enable
239 * you to monitor the current playback time/latency very precisely and
240 * very frequently without requiring a network round trip every time.
241 *
242 * \section flow_sec Overflow and underflow
243 *
244 * Even with the best precautions, buffers will sometime over - or
245 * underflow. To handle this gracefully, the application can be
246 * notified when this happens. Callbacks are registered using
247 * pa_stream_set_overflow_callback() and
248 * pa_stream_set_underflow_callback().
249 *
250 * \section sync_streams Synchronizing Multiple Playback Streams
251 *
252 * PulseAudio allows applications to fully synchronize multiple
253 * playback streams that are connected to the same output device. That
254 * means the streams will always be played back sample-by-sample
255 * synchronously. If stream operations like pa_stream_cork() are
256 * issued on one of the synchronized streams, they are simultaneously
257 * issued on the others.
258 *
259 * To synchronize a stream to another, just pass the "master" stream
260 * as last argument to pa_stream_connect_playback(). To make sure that
261 * the freshly created stream doesn't start playback right-away, make
262 * sure to pass PA_STREAM_START_CORKED and -- after all streams have
263 * been created -- uncork them all with a single call to
264 * pa_stream_cork() for the master stream.
265 *
266 * To make sure that a particular stream doesn't stop playing when a
267 * server side buffer underrun happens on it while the other
268 * synchronized streams continue playing and hence deviate, you need to
269 * pass a pa_buffer_attr with prebuf set to 0 when connecting.
270 *
271 * \section disc_sec Disconnecting
272 *
273 * When a stream has served is purpose it must be disconnected with
274 * pa_stream_disconnect(). If you only unreference it, then it will live on
275 * and eat resources both locally and on the server until you disconnect the
276 * context.
277 *
278 */
279
280/** \file
281 * Audio streams for input, output and sample upload
282 *
283 * See also \subpage streams
284 */
285
286PA_C_DECL_BEGIN
287
288/** An opaque stream for playback or recording */
289typedef struct pa_stream pa_stream;
290
291/** A generic callback for operation completion */
292typedef void (*pa_stream_success_cb_t) (pa_stream*s, int success, void *userdata);
293
294/** A generic request callback */
295typedef void (*pa_stream_request_cb_t)(pa_stream *p, size_t nbytes, void *userdata);
296
297/** A generic notification callback */
298typedef void (*pa_stream_notify_cb_t)(pa_stream *p, void *userdata);
299
300/** A callback for asynchronous meta/policy event messages. Well known
301 * event names are PA_STREAM_EVENT_REQUEST_CORK and
302 * PA_STREAM_EVENT_REQUEST_UNCORK. The set of defined events can be
303 * extended at any time. Also, server modules may introduce additional
304 * message types so make sure that your callback function ignores messages
305 * it doesn't know. \since 0.9.15 */
306typedef void (*pa_stream_event_cb_t)(pa_stream *p, const char *name, pa_proplist *pl, void *userdata);
307
308/** Create a new, unconnected stream with the specified name and
309 * sample type. It is recommended to use pa_stream_new_with_proplist()
310 * instead and specify some initial properties. */
311pa_stream* pa_stream_new(
312 pa_context *c /**< The context to create this stream in */,
313 const char *name /**< A name for this stream */,
314 const pa_sample_spec *ss /**< The desired sample format */,
315 const pa_channel_map *map /**< The desired channel map, or NULL for default */);
316
317/** Create a new, unconnected stream with the specified name and
318 * sample type, and specify the initial stream property
319 * list. \since 0.9.11 */
320pa_stream* pa_stream_new_with_proplist(
321 pa_context *c /**< The context to create this stream in */,
322 const char *name /**< A name for this stream */,
323 const pa_sample_spec *ss /**< The desired sample format */,
324 const pa_channel_map *map /**< The desired channel map, or NULL for default */,
325 pa_proplist *p /**< The initial property list */);
326
327/** Create a new, unconnected stream with the specified name, the set of formats
328 * this client can provide, and an initial list of properties. While
329 * connecting, the server will select the most appropriate format which the
330 * client must then provide. \since 1.0 */
331pa_stream *pa_stream_new_extended(
332 pa_context *c /**< The context to create this stream in */,
333 const char *name /**< A name for this stream */,
334 pa_format_info * const * formats /**< The list of formats that can be provided */,
335 unsigned int n_formats /**< The number of formats being passed in */,
336 pa_proplist *p /**< The initial property list */);
337
338/** Decrease the reference counter by one. */
339void pa_stream_unref(pa_stream *s);
340
341/** Increase the reference counter by one. */
342pa_stream *pa_stream_ref(pa_stream *s);
343
344/** Return the current state of the stream. */
345pa_stream_state_t pa_stream_get_state(pa_stream *p);
346
347/** Return the context this stream is attached to. */
348pa_context* pa_stream_get_context(pa_stream *p);
349
350/** Return the sink input resp.\ source output index this stream is
351 * identified in the server with. This is useful with the
352 * introspection functions such as pa_context_get_sink_input_info()
353 * or pa_context_get_source_output_info(). This returns PA_INVALID_INDEX
354 * on failure. */
355uint32_t pa_stream_get_index(pa_stream *s);
356
357/** Return the index of the sink or source this stream is connected to
358 * in the server. This is useful with the introspection
359 * functions such as pa_context_get_sink_info_by_index() or
360 * pa_context_get_source_info_by_index().
361 *
362 * Please note that streams may be moved between sinks/sources and thus
363 * it is recommended to use pa_stream_set_moved_callback() to be notified
364 * about this. This function will return with PA_INVALID_INDEX on failure,
365 * including the being server older than 0.9.8. \since 0.9.8 */
366uint32_t pa_stream_get_device_index(pa_stream *s);
367
368/** Return the name of the sink or source this stream is connected to
369 * in the server. This is useful with the introspection
370 * functions such as pa_context_get_sink_info_by_name()
371 * or pa_context_get_source_info_by_name().
372 *
373 * Please note that streams may be moved between sinks/sources and thus
374 * it is recommended to use pa_stream_set_moved_callback() to be notified
375 * about this. This function will fail when the server is older than
376 * 0.9.8. \since 0.9.8 */
377const char *pa_stream_get_device_name(pa_stream *s);
378
379/** Return 1 if the sink or source this stream is connected to has
380 * been suspended. This will return 0 if not, and a negative value on
381 * error. This function will return with -PA_ERR_NOTSUPPORTED when the
382 * server is older than 0.9.8. \since 0.9.8 */
383int pa_stream_is_suspended(pa_stream *s);
384
385/** Return 1 if the this stream has been corked. This will return 0 if
386 * not, and a negative value on error. \since 0.9.11 */
387int pa_stream_is_corked(pa_stream *s);
388
389/** Connect the stream to a sink. It is strongly recommended to pass
390 * NULL in both \a dev and \a volume and to set neither
391 * PA_STREAM_START_MUTED nor PA_STREAM_START_UNMUTED -- unless these
392 * options are directly dependent on user input or configuration.
393 *
394 * If you follow this rule then the sound server will have the full
395 * flexibility to choose the device, volume and mute status
396 * automatically, based on server-side policies, heuristics and stored
397 * information from previous uses. Also the server may choose to
398 * reconfigure audio devices to make other sinks/sources or
399 * capabilities available to be able to accept the stream.
400 *
401 * Before 0.9.20 it was not defined whether the \a volume parameter was
402 * interpreted relative to the sink's current volume or treated as
403 * an absolute device volume. Since 0.9.20 it is an absolute volume when
404 * the sink is in flat volume mode, and relative otherwise, thus
405 * making sure the volume passed here has always the same semantics as
406 * the volume passed to pa_context_set_sink_input_volume(). It is possible
407 * to figure out whether flat volume mode is in effect for a given sink
408 * by calling pa_context_get_sink_info_by_name().
409 *
410 * Since 5.0, it's possible to specify a single-channel volume even if the
411 * stream has multiple channels. In that case the same volume is applied to all
412 * channels.
413 *
414 * Returns zero on success. */
415int pa_stream_connect_playback(
416 pa_stream *s /**< The stream to connect to a sink */,
417 const char *dev /**< Name of the sink to connect to, or NULL for default */ ,
418 const pa_buffer_attr *attr /**< Buffering attributes, or NULL for default */,
419 pa_stream_flags_t flags /**< Additional flags, or 0 for default */,
420 const pa_cvolume *volume /**< Initial volume, or NULL for default */,
421 pa_stream *sync_stream /**< Synchronize this stream with the specified one, or NULL for a standalone stream */);
422
423/** Connect the stream to a source. Returns zero on success. */
424int pa_stream_connect_record(
425 pa_stream *s /**< The stream to connect to a source */ ,
426 const char *dev /**< Name of the source to connect to, or NULL for default */,
427 const pa_buffer_attr *attr /**< Buffer attributes, or NULL for default */,
428 pa_stream_flags_t flags /**< Additional flags, or 0 for default */);
429
430/** Disconnect a stream from a source/sink. Returns zero on success. */
431int pa_stream_disconnect(pa_stream *s);
432
433/** Prepare writing data to the server (for playback streams). This
434 * function may be used to optimize the number of memory copies when
435 * doing playback ("zero-copy"). It is recommended to call this
436 * function before each call to pa_stream_write().
437 *
438 * Pass in the address to a pointer and an address of the number of
439 * bytes you want to write. On return the two values will contain a
440 * pointer where you can place the data to write and the maximum number
441 * of bytes you can write. \a *nbytes can be smaller or have the same
442 * value as you passed in. You need to be able to handle both cases.
443 * Accessing memory beyond the returned \a *nbytes value is invalid.
444 * Accessing the memory returned after the following pa_stream_write()
445 * or pa_stream_cancel_write() is invalid.
446 *
447 * On invocation only \a *nbytes needs to be initialized, on return both
448 * *data and *nbytes will be valid. If you place (size_t) -1 in *nbytes
449 * on invocation the memory size will be chosen automatically (which is
450 * recommended to do). After placing your data in the memory area
451 * returned, call pa_stream_write() with \a data set to an address
452 * within this memory area and an \a nbytes value that is smaller or
453 * equal to what was returned by this function to actually execute the
454 * write.
455 *
456 * An invocation of pa_stream_write() should follow "quickly" on
457 * pa_stream_begin_write(). It is not recommended letting an unbounded
458 * amount of time pass after calling pa_stream_begin_write() and
459 * before calling pa_stream_write(). If you want to cancel a
460 * previously called pa_stream_begin_write() without calling
461 * pa_stream_write() use pa_stream_cancel_write(). Calling
462 * pa_stream_begin_write() twice without calling pa_stream_write() or
463 * pa_stream_cancel_write() in between will return exactly the same
464 * \a data pointer and \a nbytes values.
465 *
466 * On success, will return zero and a valid (non-NULL) pointer. If the
467 * return value is non-zero, or the pointer is NULL, this indicates an
468 * error. Callers should also pay careful attention to the returned
469 * length, which may not be the same as that passed in, as mentioned above.
470 *
471 * \since 0.9.16 */
472int pa_stream_begin_write(
473 pa_stream *p,
474 void **data,
475 size_t *nbytes);
476
477/** Reverses the effect of pa_stream_begin_write() dropping all data
478 * that has already been placed in the memory area returned by
479 * pa_stream_begin_write(). Only valid to call if
480 * pa_stream_begin_write() was called before and neither
481 * pa_stream_cancel_write() nor pa_stream_write() have been called
482 * yet. Accessing the memory previously returned by
483 * pa_stream_begin_write() after this call is invalid. Any further
484 * explicit freeing of the memory area is not necessary.
485 * Returns zero on success. \since 0.9.16 */
486int pa_stream_cancel_write(
487 pa_stream *p);
488
489/** Write some data to the server (for playback streams).
490 * If \a free_cb is non-NULL this routine is called when all data has
491 * been written out. An internal reference to the specified data is
492 * kept, the data is not copied. If NULL, the data is copied into an
493 * internal buffer.
494 *
495 * The client may freely seek around in the output buffer. For
496 * most applications it is typical to pass 0 and PA_SEEK_RELATIVE
497 * as values for the arguments \a offset and \a seek respectively.
498 * After a successful write call the write index will be at the
499 * position after where this chunk of data has been written to.
500 *
501 * As an optimization for avoiding needless memory copies you may call
502 * pa_stream_begin_write() before this call and then place your audio
503 * data directly in the memory area returned by that call. Then, pass
504 * a pointer to that memory area to pa_stream_write(). After the
505 * invocation of pa_stream_write() the memory area may no longer be
506 * accessed. Any further explicit freeing of the memory area is not
507 * necessary. It is OK to write to the memory area returned by
508 * pa_stream_begin_write() only partially with this call, skipping
509 * bytes both at the end and at the beginning of the reserved memory
510 * area.
511 *
512 * Returns zero on success. */
513int pa_stream_write(
514 pa_stream *p /**< The stream to use */,
515 const void *data /**< The data to write */,
516 size_t nbytes /**< The length of the data to write in bytes, must be in multiples of the stream's sample spec frame size */,
517 pa_free_cb_t free_cb /**< A cleanup routine for the data or NULL to request an internal copy */,
518 int64_t offset /**< Offset for seeking, must be 0 for upload streams, must be in multiples of the stream's sample spec frame size */,
519 pa_seek_mode_t seek /**< Seek mode, must be PA_SEEK_RELATIVE for upload streams */);
520
521/** Function does exactly the same as pa_stream_write() with the difference
522 * that free_cb_data is passed to free_cb instead of data. \since 6.0 */
523int pa_stream_write_ext_free(
524 pa_stream *p /**< The stream to use */,
525 const void *data /**< The data to write */,
526 size_t nbytes /**< The length of the data to write in bytes */,
527 pa_free_cb_t free_cb /**< A cleanup routine for the data or NULL to request an internal copy */,
528 void *free_cb_data /**< Argument passed to free_cb function */,
529 int64_t offset /**< Offset for seeking, must be 0 for upload streams */,
530 pa_seek_mode_t seek /**< Seek mode, must be PA_SEEK_RELATIVE for upload streams */);
531
532/** Read the next fragment from the buffer (for recording streams).
533 * If there is data at the current read index, \a data will point to
534 * the actual data and \a nbytes will contain the size of the data in
535 * bytes (which can be less or more than a complete fragment).
536 *
537 * If there is no data at the current read index, it means that either
538 * the buffer is empty or it contains a hole (that is, the write index
539 * is ahead of the read index but there's no data where the read index
540 * points at). If the buffer is empty, \a data will be NULL and
541 * \a nbytes will be 0. If there is a hole, \a data will be NULL and
542 * \a nbytes will contain the length of the hole.
543 *
544 * Use pa_stream_drop() to actually remove the data from the buffer
545 * and move the read index forward. pa_stream_drop() should not be
546 * called if the buffer is empty, but it should be called if there is
547 * a hole.
548 *
549 * Returns zero on success, negative on error. */
550int pa_stream_peek(
551 pa_stream *p /**< The stream to use */,
552 const void **data /**< Pointer to pointer that will point to data */,
553 size_t *nbytes /**< The length of the data read in bytes */);
554
555/** Remove the current fragment on record streams. It is invalid to do this without first
556 * calling pa_stream_peek(). Returns zero on success. */
557int pa_stream_drop(pa_stream *p);
558
559/** Return the number of bytes requested by the server that have not yet
560 * been written.
561 *
562 * It is possible to write more than this amount, up to the stream's
563 * buffer_attr.maxlength bytes. This is usually not desirable, though, as
564 * it would increase stream latency to be higher than requested
565 * (buffer_attr.tlength).
566 *
567 * (size_t) -1 is returned on error.
568 */
569size_t pa_stream_writable_size(pa_stream *p);
570
571/** Return the number of bytes that may be read using pa_stream_peek().
572 *
573 * (size_t) -1 is returned on error. */
574size_t pa_stream_readable_size(pa_stream *p);
575
576/** Drain a playback stream. Use this for notification when the
577 * playback buffer is empty after playing all the audio in the buffer.
578 * Please note that only one drain operation per stream may be issued
579 * at a time. */
580pa_operation* pa_stream_drain(pa_stream *s, pa_stream_success_cb_t cb, void *userdata);
581
582/** Request a timing info structure update for a stream. Use
583 * pa_stream_get_timing_info() to get access to the raw timing data,
584 * or pa_stream_get_time() or pa_stream_get_latency() to get cleaned
585 * up values. */
586pa_operation* pa_stream_update_timing_info(pa_stream *p, pa_stream_success_cb_t cb, void *userdata);
587
588/** Set the callback function that is called whenever the state of the stream changes. */
589void pa_stream_set_state_callback(pa_stream *s, pa_stream_notify_cb_t cb, void *userdata);
590
591/** Set the callback function that is called when new data may be
592 * written to the stream. */
593void pa_stream_set_write_callback(pa_stream *p, pa_stream_request_cb_t cb, void *userdata);
594
595/** Set the callback function that is called when new data is available from the stream. */
596void pa_stream_set_read_callback(pa_stream *p, pa_stream_request_cb_t cb, void *userdata);
597
598/** Set the callback function that is called when a buffer overflow happens. (Only for playback streams) */
599void pa_stream_set_overflow_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
600
601/** Return at what position the latest underflow occurred, or -1 if this information is not
602 * known (e.g.\ if no underflow has occurred, or server is older than 1.0).
603 * Can be used inside the underflow callback to get information about the current underflow.
604 * (Only for playback streams) \since 1.0 */
605int64_t pa_stream_get_underflow_index(pa_stream *p);
606
607/** Set the callback function that is called when a buffer underflow happens. (Only for playback streams) */
608void pa_stream_set_underflow_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
609
610/** Set the callback function that is called when the server starts
611 * playback after an underrun or on initial startup. This only informs
612 * that audio is flowing again, it is no indication that audio started
613 * to reach the speakers already. (Only for playback streams) \since
614 * 0.9.11 */
615void pa_stream_set_started_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
616
617/** Set the callback function that is called whenever a latency
618 * information update happens. Useful on PA_STREAM_AUTO_TIMING_UPDATE
619 * streams only. */
620void pa_stream_set_latency_update_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
621
622/** Set the callback function that is called whenever the stream is
623 * moved to a different sink/source. Use pa_stream_get_device_name() or
624 * pa_stream_get_device_index() to query the new sink/source. This
625 * notification is only generated when the server is at least
626 * 0.9.8. \since 0.9.8 */
627void pa_stream_set_moved_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
628
629/** Set the callback function that is called whenever the sink/source
630 * this stream is connected to is suspended or resumed. Use
631 * pa_stream_is_suspended() to query the new suspend status. Please
632 * note that the suspend status might also change when the stream is
633 * moved between devices. Thus if you call this function you very
634 * likely want to call pa_stream_set_moved_callback() too. This
635 * notification is only generated when the server is at least
636 * 0.9.8. \since 0.9.8 */
637void pa_stream_set_suspended_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
638
639/** Set the callback function that is called whenever a meta/policy
640 * control event is received. \since 0.9.15 */
641void pa_stream_set_event_callback(pa_stream *p, pa_stream_event_cb_t cb, void *userdata);
642
643/** Set the callback function that is called whenever the buffer
644 * attributes on the server side change. Please note that the buffer
645 * attributes can change when moving a stream to a different
646 * sink/source too, hence if you use this callback you should use
647 * pa_stream_set_moved_callback() as well. \since 0.9.15 */
648void pa_stream_set_buffer_attr_callback(pa_stream *p, pa_stream_notify_cb_t cb, void *userdata);
649
650/** Pause (or resume) playback of this stream temporarily. Available
651 * on both playback and recording streams. If \a b is 1 the stream is
652 * paused. If \a b is 0 the stream is resumed. The pause/resume operation
653 * is executed as quickly as possible. If a cork is very quickly
654 * followed by an uncork or the other way round, this might not
655 * actually have any effect on the stream that is output. You can use
656 * pa_stream_is_corked() to find out whether the stream is currently
657 * paused or not. Normally a stream will be created in uncorked
658 * state. If you pass PA_STREAM_START_CORKED as a flag when connecting
659 * the stream, it will be created in corked state. */
660pa_operation* pa_stream_cork(pa_stream *s, int b, pa_stream_success_cb_t cb, void *userdata);
661
662/** Flush the playback or record buffer of this stream. This discards any audio data
663 * in the buffer. Most of the time you're better off using the parameter
664 * \a seek of pa_stream_write() instead of this function. */
665pa_operation* pa_stream_flush(pa_stream *s, pa_stream_success_cb_t cb, void *userdata);
666
667/** Reenable prebuffering if specified in the pa_buffer_attr
668 * structure. Available for playback streams only. */
669pa_operation* pa_stream_prebuf(pa_stream *s, pa_stream_success_cb_t cb, void *userdata);
670
671/** Request immediate start of playback on this stream. This disables
672 * prebuffering temporarily if specified in the pa_buffer_attr structure.
673 * Available for playback streams only. */
674pa_operation* pa_stream_trigger(pa_stream *s, pa_stream_success_cb_t cb, void *userdata);
675
676/** Rename the stream. */
677pa_operation* pa_stream_set_name(pa_stream *s, const char *name, pa_stream_success_cb_t cb, void *userdata);
678
679/** Return the current playback/recording time. This is based on the
680 * data in the timing info structure returned by
681 * pa_stream_get_timing_info(). The returned time is in the sound card
682 * clock domain, which usually runs at a slightly different rate than
683 * the system clock.
684 *
685 * This function will usually only return new data if a timing info
686 * update has been received. Only if timing interpolation has been
687 * requested (PA_STREAM_INTERPOLATE_TIMING) the data from the last
688 * timing update is used for an estimation of the current
689 * playback/recording time based on the local time that passed since
690 * the timing info structure has been acquired.
691 *
692 * The time value returned by this function is guaranteed to increase
693 * monotonically (the returned value is always greater
694 * or equal to the value returned by the last call). This behaviour
695 * can be disabled by using PA_STREAM_NOT_MONOTONIC. This may be
696 * desirable to better deal with bad estimations of transport
697 * latencies, but may have strange effects if the application is not
698 * able to deal with time going 'backwards'.
699 *
700 * The time interpolator activated by PA_STREAM_INTERPOLATE_TIMING
701 * favours 'smooth' time graphs over accurate ones to improve the
702 * smoothness of UI operations that are tied to the audio clock. If
703 * accuracy is more important to you, you might need to estimate your
704 * timing based on the data from pa_stream_get_timing_info() yourself
705 * or not work with interpolated timing at all and instead always
706 * query the server side for the most up to date timing with
707 * pa_stream_update_timing_info().
708 *
709 * If no timing information has been
710 * received yet this call will return -PA_ERR_NODATA. For more details
711 * see pa_stream_get_timing_info().
712 *
713 * Returns zero on success, negative on error. */
714int pa_stream_get_time(pa_stream *s, pa_usec_t *r_usec);
715
716/** Determine the total stream latency. This function is based on
717 * pa_stream_get_time(). The returned time is in the sound card clock
718 * domain, which usually runs at a slightly different rate than the
719 * system clock.
720 *
721 * The latency is stored in \a *r_usec. In case the stream is a
722 * monitoring stream the result can be negative, i.e. the captured
723 * samples are not yet played. In this case \a *negative is set to 1.
724 *
725 * If no timing information has been received yet, this call will
726 * return -PA_ERR_NODATA. On success, it will return 0.
727 *
728 * For more details see pa_stream_get_timing_info() and
729 * pa_stream_get_time(). */
730int pa_stream_get_latency(pa_stream *s, pa_usec_t *r_usec, int *negative);
731
732/** Return the latest raw timing data structure. The returned pointer
733 * refers to an internal read-only instance of the timing
734 * structure. The user should make a copy of this structure if
735 * wanting to modify it. An in-place update to this data structure
736 * may be requested using pa_stream_update_timing_info().
737 *
738 * If no timing information has been received before (i.e. by
739 * requesting pa_stream_update_timing_info() or by using
740 * PA_STREAM_AUTO_TIMING_UPDATE), this function will return NULL.
741 *
742 * Please note that the write_index member field (and only this field)
743 * is updated on each pa_stream_write() call, not just when a timing
744 * update has been received. */
745const pa_timing_info* pa_stream_get_timing_info(pa_stream *s);
746
747/** Return a pointer to the stream's sample specification. */
748const pa_sample_spec* pa_stream_get_sample_spec(pa_stream *s);
749
750/** Return a pointer to the stream's channel map. */
751const pa_channel_map* pa_stream_get_channel_map(pa_stream *s);
752
753/** Return a pointer to the stream's format. \since 1.0 */
754const pa_format_info* pa_stream_get_format_info(pa_stream *s);
755
756/** Return the per-stream server-side buffer metrics of the
757 * stream. Only valid after the stream has been connected successfully
758 * and if the server is at least PulseAudio 0.9. This will return the
759 * actual configured buffering metrics, which may differ from what was
760 * requested during pa_stream_connect_record() or
761 * pa_stream_connect_playback(). This call will always return the
762 * actual per-stream server-side buffer metrics, regardless whether
763 * PA_STREAM_ADJUST_LATENCY is set or not. \since 0.9.0 */
764const pa_buffer_attr* pa_stream_get_buffer_attr(pa_stream *s);
765
766/** Change the buffer metrics of the stream during playback. The
767 * server might have chosen different buffer metrics than
768 * requested. The selected metrics may be queried with
769 * pa_stream_get_buffer_attr() as soon as the callback is called. Only
770 * valid after the stream has been connected successfully and if the
771 * server is at least PulseAudio 0.9.8. Please be aware of the
772 * slightly different semantics of the call depending whether
773 * PA_STREAM_ADJUST_LATENCY is set or not. \since 0.9.8 */
774pa_operation *pa_stream_set_buffer_attr(pa_stream *s, const pa_buffer_attr *attr, pa_stream_success_cb_t cb, void *userdata);
775
776/** Change the stream sampling rate during playback. You need to pass
777 * PA_STREAM_VARIABLE_RATE in the flags parameter of
778 * pa_stream_connect_playback() if you plan to use this function. Only valid
779 * after the stream has been connected successfully and if the server
780 * is at least PulseAudio 0.9.8. \since 0.9.8 */
781pa_operation *pa_stream_update_sample_rate(pa_stream *s, uint32_t rate, pa_stream_success_cb_t cb, void *userdata);
782
783/** Update the property list of the sink input/source output of this
784 * stream, adding new entries. Please note that it is highly
785 * recommended to set as many properties initially via
786 * pa_stream_new_with_proplist() as possible instead a posteriori with
787 * this function, since that information may be used to route
788 * this stream to the right device. \since 0.9.11 */
789pa_operation *pa_stream_proplist_update(pa_stream *s, pa_update_mode_t mode, pa_proplist *p, pa_stream_success_cb_t cb, void *userdata);
790
791/** Update the property list of the sink input/source output of this
792 * stream, remove entries. \since 0.9.11 */
793pa_operation *pa_stream_proplist_remove(pa_stream *s, const char *const keys[], pa_stream_success_cb_t cb, void *userdata);
794
795/** For record streams connected to a monitor source: monitor only a
796 * very specific sink input of the sink. This function needs to be
797 * called before pa_stream_connect_record() is called.
798 * Returns zero on success, negative on error. \since 0.9.11 */
799int pa_stream_set_monitor_stream(pa_stream *s, uint32_t sink_input_idx);
800
801/** Return the sink input index previously set with
802 * pa_stream_set_monitor_stream(). Returns PA_INVALID_INDEX
803 * on failure. \since 0.9.11 */
804uint32_t pa_stream_get_monitor_stream(pa_stream *s);
805
806PA_C_DECL_END
807
808#endif
809