2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000,2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.h: Header for GstElement
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
24 #ifndef __GST_ELEMENT_H__
25 #define __GST_ELEMENT_H__
31 /* gstelement.h and gstelementfactory.h include eachother */
32 typedef struct _GstElement GstElement;
33 typedef struct _GstElementClass GstElementClass;
35 /* gstmessage.h needs State */
38 * @GST_STATE_VOID_PENDING: no pending state.
39 * @GST_STATE_NULL : the NULL state or initial state of an element.
40 * @GST_STATE_READY : the element is ready to go to PAUSED.
41 * @GST_STATE_PAUSED : the element is PAUSED, it is ready to accept and
42 * process data. Sink elements however only accept one
43 * buffer and then block.
44 * @GST_STATE_PLAYING : the element is PLAYING, the #GstClock is running and
45 * the data is flowing.
47 * The possible states an element can be in. States can be changed using
48 * gst_element_set_state() and checked using gst_element_get_state().
51 GST_STATE_VOID_PENDING = 0,
58 #define GST_TYPE_ELEMENT (gst_element_get_type ())
59 #define GST_IS_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_ELEMENT))
60 #define GST_IS_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_ELEMENT))
61 #define GST_ELEMENT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_ELEMENT, GstElementClass))
62 #define GST_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_ELEMENT, GstElement))
63 #define GST_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_ELEMENT, GstElementClass))
64 #define GST_ELEMENT_CAST(obj) ((GstElement*)(obj))
67 * GstStateChangeReturn:
68 * @GST_STATE_CHANGE_FAILURE : the state change failed
69 * @GST_STATE_CHANGE_SUCCESS : the state change succeeded
70 * @GST_STATE_CHANGE_ASYNC : the state change will happen asynchronously
71 * @GST_STATE_CHANGE_NO_PREROLL: the state change succeeded but the element
72 * cannot produce data in %GST_STATE_PAUSED.
73 * This typically happens with live sources.
75 * The possible return values from a state change function such as
76 * gst_element_set_state(). Only @GST_STATE_CHANGE_FAILURE is a real failure.
79 GST_STATE_CHANGE_FAILURE = 0,
80 GST_STATE_CHANGE_SUCCESS = 1,
81 GST_STATE_CHANGE_ASYNC = 2,
82 GST_STATE_CHANGE_NO_PREROLL = 3
83 } GstStateChangeReturn;
85 #include <gst/gstconfig.h>
86 #include <gst/gstobject.h>
87 #include <gst/gstpad.h>
88 #include <gst/gstbus.h>
89 #include <gst/gstclock.h>
90 #include <gst/gstelementfactory.h>
91 #include <gst/gstplugin.h>
92 #include <gst/gstpluginfeature.h>
93 #include <gst/gstiterator.h>
94 #include <gst/gstmessage.h>
95 #include <gst/gstquery.h>
96 #include <gst/gsttaglist.h>
97 #include <gst/gstcontext.h>
99 /* NOTE: this probably should be done with an #ifdef to decide
100 * whether to safe-cast or to just do the non-checking cast.
105 * @elem: a #GstElement to return state for.
107 * This macro returns the current #GstState of the element.
109 #define GST_STATE(elem) (GST_ELEMENT_CAST(elem)->current_state)
113 * @elem: a #GstElement to return the next state for.
115 * This macro returns the next #GstState of the element.
117 #define GST_STATE_NEXT(elem) (GST_ELEMENT_CAST(elem)->next_state)
121 * @elem: a #GstElement to return the pending state for.
123 * This macro returns the currently pending #GstState of the element.
125 #define GST_STATE_PENDING(elem) (GST_ELEMENT_CAST(elem)->pending_state)
129 * @elem: a #GstElement to return the target state for.
131 * This macro returns the target #GstState of the element.
133 #define GST_STATE_TARGET(elem) (GST_ELEMENT_CAST(elem)->target_state)
137 * @elem: a #GstElement to return the last state result for.
139 * This macro returns the last #GstStateChangeReturn value.
141 #define GST_STATE_RETURN(elem) (GST_ELEMENT_CAST(elem)->last_return)
143 #define __GST_SIGN(val) ((val) < 0 ? -1 : ((val) > 0 ? 1 : 0))
145 * GST_STATE_GET_NEXT:
146 * @cur: A starting #GstState
147 * @pending: A target #GstState
149 * Given a current state @cur and a target state @pending, calculate the next (intermediate)
152 #define GST_STATE_GET_NEXT(cur,pending) ((GstState)((cur) + __GST_SIGN ((gint)(pending) - (gint)(cur))))
154 * GST_STATE_TRANSITION:
155 * @cur: A current state
156 * @next: A next state
158 * Given a current state @cur and a next state @next, calculate the associated
159 * #GstStateChange transition.
161 #define GST_STATE_TRANSITION(cur,next) ((GstStateChange)(((cur)<<3)|(next)))
163 * GST_STATE_TRANSITION_CURRENT:
164 * @trans: A #GstStateChange
166 * Given a state transition @trans, extract the current #GstState.
168 #define GST_STATE_TRANSITION_CURRENT(trans) ((GstState)((trans)>>3))
170 * GST_STATE_TRANSITION_NEXT:
171 * @trans: A #GstStateChange
173 * Given a state transition @trans, extract the next #GstState.
175 #define GST_STATE_TRANSITION_NEXT(trans) ((GstState)((trans)&0x7))
179 * @GST_STATE_CHANGE_NULL_TO_READY : state change from NULL to READY.
181 * * The element must check if the resources it needs are available. Device
182 * sinks and -sources typically try to probe the device to constrain their
184 * * The element opens the device (in case feature need to be probed).
186 * @GST_STATE_CHANGE_READY_TO_PAUSED : state change from READY to PAUSED.
188 * * The element pads are activated in order to receive data in PAUSED.
189 * Streaming threads are started.
190 * * Some elements might need to return %GST_STATE_CHANGE_ASYNC and complete
191 * the state change when they have enough information. It is a requirement
192 * for sinks to return %GST_STATE_CHANGE_ASYNC and complete the state change
193 * when they receive the first buffer or %GST_EVENT_EOS (preroll).
194 * Sinks also block the dataflow when in PAUSED.
195 * * A pipeline resets the running_time to 0.
197 * * Live sources return %GST_STATE_CHANGE_NO_PREROLL and don't generate data.
199 * @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING.
201 * * Most elements ignore this state change.
202 * * The pipeline selects a #GstClock and distributes this to all the children
203 * before setting them to PLAYING. This means that it is only allowed to
204 * synchronize on the #GstClock in the PLAYING state.
205 * * The pipeline uses the #GstClock and the running_time to calculate the
206 * base_time. The base_time is distributed to all children when performing
208 * * Sink elements stop blocking on the preroll buffer or event and start
209 * rendering the data.
210 * * Sinks can post %GST_MESSAGE_EOS in the PLAYING state. It is not allowed
211 * to post %GST_MESSAGE_EOS when not in the PLAYING state.
212 * * While streaming in PAUSED or PLAYING elements can create and remove
214 * * Live sources start generating data and return %GST_STATE_CHANGE_SUCCESS.
216 * @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED.
218 * * Most elements ignore this state change.
219 * * The pipeline calculates the running_time based on the last selected
220 * #GstClock and the base_time. It stores this information to continue
221 * playback when going back to the PLAYING state.
223 * * Sinks unblock any #GstClock wait calls.
224 * * When a sink does not have a pending buffer to play, it returns
225 * #GST_STATE_CHANGE_ASYNC from this state change and completes the state
226 * change when it receives a new buffer or an %GST_EVENT_EOS.
227 * * Any queued %GST_MESSAGE_EOS items are removed since they will be reposted
228 * when going back to the PLAYING state. The EOS messages are queued in
229 * #GstBin containers.
231 * * Live sources stop generating data and return %GST_STATE_CHANGE_NO_PREROLL.
233 * @GST_STATE_CHANGE_PAUSED_TO_READY : state change from PAUSED to READY.
235 * * Sinks unblock any waits in the preroll.
236 * * Elements unblock any waits on devices
237 * * Chain or get_range functions return %GST_FLOW_FLUSHING.
238 * * The element pads are deactivated so that streaming becomes impossible and
239 * all streaming threads are stopped.
240 * * The sink forgets all negotiated formats
241 * * Elements remove all sometimes pads
243 * @GST_STATE_CHANGE_READY_TO_NULL : state change from READY to NULL.
245 * * Elements close devices
246 * * Elements reset any internal state.
248 * These are the different state changes an element goes through.
249 * %GST_STATE_NULL ⇒ %GST_STATE_PLAYING is called an upwards state change
250 * and %GST_STATE_PLAYING ⇒ %GST_STATE_NULL a downwards state change.
252 typedef enum /*< flags=0 >*/
254 GST_STATE_CHANGE_NULL_TO_READY = (GST_STATE_NULL<<3) | GST_STATE_READY,
255 GST_STATE_CHANGE_READY_TO_PAUSED = (GST_STATE_READY<<3) | GST_STATE_PAUSED,
256 GST_STATE_CHANGE_PAUSED_TO_PLAYING = (GST_STATE_PAUSED<<3) | GST_STATE_PLAYING,
257 GST_STATE_CHANGE_PLAYING_TO_PAUSED = (GST_STATE_PLAYING<<3) | GST_STATE_PAUSED,
258 GST_STATE_CHANGE_PAUSED_TO_READY = (GST_STATE_PAUSED<<3) | GST_STATE_READY,
259 GST_STATE_CHANGE_READY_TO_NULL = (GST_STATE_READY<<3) | GST_STATE_NULL
264 * @GST_ELEMENT_FLAG_LOCKED_STATE: ignore state changes from parent
265 * @GST_ELEMENT_FLAG_SINK: the element is a sink
266 * @GST_ELEMENT_FLAG_SOURCE: the element is a source.
267 * @GST_ELEMENT_FLAG_PROVIDE_CLOCK: the element can provide a clock
268 * @GST_ELEMENT_FLAG_REQUIRE_CLOCK: the element requires a clock
269 * @GST_ELEMENT_FLAG_INDEXABLE: the element can use an index
270 * @GST_ELEMENT_FLAG_LAST: offset to define more flags
272 * The standard flags that an element may have.
276 GST_ELEMENT_FLAG_LOCKED_STATE = (GST_OBJECT_FLAG_LAST << 0),
277 GST_ELEMENT_FLAG_SINK = (GST_OBJECT_FLAG_LAST << 1),
278 GST_ELEMENT_FLAG_SOURCE = (GST_OBJECT_FLAG_LAST << 2),
279 GST_ELEMENT_FLAG_PROVIDE_CLOCK = (GST_OBJECT_FLAG_LAST << 3),
280 GST_ELEMENT_FLAG_REQUIRE_CLOCK = (GST_OBJECT_FLAG_LAST << 4),
281 GST_ELEMENT_FLAG_INDEXABLE = (GST_OBJECT_FLAG_LAST << 5),
283 GST_ELEMENT_FLAG_LAST = (GST_OBJECT_FLAG_LAST << 10)
287 * GST_ELEMENT_IS_LOCKED_STATE:
288 * @elem: A #GstElement to query
290 * Check if the element is in the locked state and therefore will ignore state
291 * changes from its parent object.
293 #define GST_ELEMENT_IS_LOCKED_STATE(elem) (GST_OBJECT_FLAG_IS_SET(elem,GST_ELEMENT_FLAG_LOCKED_STATE))
297 * @elem: A #GstElement to query
299 * Gets the name of this element. This is not thread-safe by default
300 * (i.e. you will have to make sure the object lock is taken yourself).
301 * If in doubt use gst_element_get_name() instead.
303 #define GST_ELEMENT_NAME(elem) (GST_OBJECT_NAME(elem))
306 * GST_ELEMENT_PARENT:
307 * @elem: A #GstElement to query
309 * Get the parent object of this element. This is not thread-safe by default
310 * (i.e. you will have to make sure the object lock is taken yourself).
311 * If in doubt use gst_object_get_parent() instead.
313 #define GST_ELEMENT_PARENT(elem) (GST_ELEMENT_CAST(GST_OBJECT_PARENT(elem)))
317 * @elem: A #GstElement to query
319 * Get the message bus of this element. This is not thread-safe by default
320 * (i.e. you will have to make sure the object lock is taken yourself).
321 * If in doubt use gst_element_get_bus() instead.
323 #define GST_ELEMENT_BUS(elem) (GST_ELEMENT_CAST(elem)->bus)
327 * @elem: A #GstElement to query
329 * Get the clock of this element.This is not thread-safe by default
330 * (i.e. you will have to make sure it is safe yourself).
331 * If in doubt use gst_element_get_clock() instead.
333 #define GST_ELEMENT_CLOCK(elem) (GST_ELEMENT_CAST(elem)->clock)
337 * @elem: A #GstElement to query
339 * Get the pads of this elements.
341 #define GST_ELEMENT_PADS(elem) (GST_ELEMENT_CAST(elem)->pads)
344 * GST_ELEMENT_START_TIME:
345 * @elem: a #GstElement to return the start time for.
347 * This macro returns the start_time of the @elem. The start_time is the
348 * running_time of the pipeline when the element went to PAUSED.
350 #define GST_ELEMENT_START_TIME(elem) (GST_ELEMENT_CAST(elem)->start_time)
352 GstStructure *gst_make_element_message_details (const char *name, ...);
353 #define GST_ELEMENT_MESSAGE_MAKE_DETAILS(args) gst_make_element_message_details args
356 * GST_ELEMENT_FLOW_ERROR:
357 * @el: the element that generates the error
358 * @flow_return: the GstFlowReturn leading to that ERROR message
360 * Utility function that elements can use in case they encountered a fatal
361 * data processing error due to wrong flow processing.
365 #define GST_ELEMENT_FLOW_ERROR(el,flow_return) \
367 GST_ELEMENT_ERROR_WITH_DETAILS (el, STREAM, FAILED, \
368 ("Internal data stream error."), \
369 ("streaming stopped, reason %s (%d)", gst_flow_get_name (flow_return), flow_return), \
370 ("flow-return", G_TYPE_INT, flow_return, NULL));\
374 * GST_ELEMENT_ERROR_WITH_DETAILS:
375 * @el: the element that generates the error
376 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
377 * @code: error code defined for that domain (see #gstreamer-GstGError)
378 * @text: the message to display (format string and args enclosed in
380 * @debug: debugging information for the message (format string and args
381 enclosed in parentheses)
382 * @args: optional name, type, value triplets, which will be stored
383 * in the associated GstStructure. NULL terminator required.
384 * Must be enclosed within parentheses.
386 * Utility function that elements can use in case they encountered a fatal
387 * data processing error. The pipeline will post an error message and the
388 * application will be requested to stop further media processing.
392 #define GST_ELEMENT_ERROR_WITH_DETAILS(el,domain,code,text,debug,args) \
394 gchar *__txt = _gst_element_error_printf text; \
395 gchar *__dbg = _gst_element_error_printf debug; \
397 GST_WARNING_OBJECT (el, "error: %s", __txt); \
399 GST_WARNING_OBJECT (el, "error: %s", __dbg); \
400 gst_element_message_full_with_details (GST_ELEMENT(el), \
401 GST_MESSAGE_ERROR, GST_ ## domain ## _ERROR, \
402 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
403 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
408 * @el: the element that generates the error
409 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
410 * @code: error code defined for that domain (see #gstreamer-GstGError)
411 * @text: the message to display (format string and args enclosed in
413 * @debug: debugging information for the message (format string and args
414 enclosed in parentheses)
416 * Utility function that elements can use in case they encountered a fatal
417 * data processing error. The pipeline will post an error message and the
418 * application will be requested to stop further media processing.
420 #define GST_ELEMENT_ERROR(el,domain,code,text,debug) \
422 gchar *__txt = _gst_element_error_printf text; \
423 gchar *__dbg = _gst_element_error_printf debug; \
425 GST_WARNING_OBJECT (el, "error: %s", __txt); \
427 GST_WARNING_OBJECT (el, "error: %s", __dbg); \
428 gst_element_message_full (GST_ELEMENT(el), \
429 GST_MESSAGE_ERROR, GST_ ## domain ## _ERROR, \
430 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
431 GST_FUNCTION, __LINE__); \
435 * GST_ELEMENT_WARNING_WITH_DETAILS:
436 * @el: the element that generates the warning
437 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
438 * @code: error code defined for that domain (see #gstreamer-GstGError)
439 * @text: the message to display (format string and args enclosed in
441 * @debug: debugging information for the message (format string and args
442 enclosed in parentheses)
443 * @args: optional name, type, value triplets, which will be stored
444 * in the associated GstStructure. NULL terminator required.
445 * Must be enclosed within parentheses.
447 * Utility function that elements can use in case they encountered a non-fatal
448 * data processing problem. The pipeline will post a warning message and the
449 * application will be informed.
453 #define GST_ELEMENT_WARNING_WITH_DETAILS(el, domain, code, text, debug, args)\
455 gchar *__txt = _gst_element_error_printf text; \
456 gchar *__dbg = _gst_element_error_printf debug; \
458 GST_WARNING_OBJECT (el, "warning: %s", __txt); \
460 GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
461 gst_element_message_full_with_details (GST_ELEMENT(el), \
462 GST_MESSAGE_WARNING, GST_ ## domain ## _ERROR, \
463 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
464 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
468 * GST_ELEMENT_WARNING:
469 * @el: the element that generates the warning
470 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
471 * @code: error code defined for that domain (see #gstreamer-GstGError)
472 * @text: the message to display (format string and args enclosed in
474 * @debug: debugging information for the message (format string and args
475 enclosed in parentheses)
477 * Utility function that elements can use in case they encountered a non-fatal
478 * data processing problem. The pipeline will post a warning message and the
479 * application will be informed.
481 #define GST_ELEMENT_WARNING(el, domain, code, text, debug) \
483 gchar *__txt = _gst_element_error_printf text; \
484 gchar *__dbg = _gst_element_error_printf debug; \
486 GST_WARNING_OBJECT (el, "warning: %s", __txt); \
488 GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
489 gst_element_message_full (GST_ELEMENT(el), \
490 GST_MESSAGE_WARNING, GST_ ## domain ## _ERROR, \
491 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
492 GST_FUNCTION, __LINE__); \
496 * GST_ELEMENT_INFO_WITH_DETAILS:
497 * @el: the element that generates the information
498 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
499 * @code: error code defined for that domain (see #gstreamer-GstGError)
500 * @text: the message to display (format string and args enclosed in
502 * @debug: debugging information for the message (format string and args
503 enclosed in parentheses)
504 * @args: optional name, type, value triplets, which will be stored
505 * in the associated GstStructure. NULL terminator required.
506 * Must be enclosed within parentheses.
508 * Utility function that elements can use in case they want to inform
509 * the application of something noteworthy that is not an error.
510 * The pipeline will post a info message and the
511 * application will be informed.
512 * Optional name, type, value triplets may be supplied, and will be stored
513 * in the associated GstStructure. NULL terminator required.
517 #define GST_ELEMENT_INFO_WITH_DETAILS(el, domain, code, text, debug, args) \
519 gchar *__txt = _gst_element_error_printf text; \
520 gchar *__dbg = _gst_element_error_printf debug; \
522 GST_INFO_OBJECT (el, "info: %s", __txt); \
524 GST_INFO_OBJECT (el, "info: %s", __dbg); \
525 gst_element_message_full_with_details (GST_ELEMENT(el), \
526 GST_MESSAGE_INFO, GST_ ## domain ## _ERROR, \
527 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
528 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
533 * @el: the element that generates the information
534 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
535 * @code: error code defined for that domain (see #gstreamer-GstGError)
536 * @text: the message to display (format string and args enclosed in
538 * @debug: debugging information for the message (format string and args
539 enclosed in parentheses)
541 * Utility function that elements can use in case they want to inform
542 * the application of something noteworthy that is not an error.
543 * The pipeline will post a info message and the
544 * application will be informed.
546 #define GST_ELEMENT_INFO(el, domain, code, text, debug) \
548 gchar *__txt = _gst_element_error_printf text; \
549 gchar *__dbg = _gst_element_error_printf debug; \
551 GST_INFO_OBJECT (el, "info: %s", __txt); \
553 GST_INFO_OBJECT (el, "info: %s", __dbg); \
554 gst_element_message_full (GST_ELEMENT(el), \
555 GST_MESSAGE_INFO, GST_ ## domain ## _ERROR, \
556 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
557 GST_FUNCTION, __LINE__); \
560 /* the state change mutexes and conds */
562 * GST_STATE_GET_LOCK:
563 * @elem: a #GstElement
565 * Get a reference to the state lock of @elem.
566 * This lock is used by the core. It is taken while getting or setting
567 * the state, during state changes, and while finalizing.
569 #define GST_STATE_GET_LOCK(elem) (&(GST_ELEMENT_CAST(elem)->state_lock))
571 * GST_STATE_GET_COND:
572 * @elem: a #GstElement
574 * Get the conditional used to signal the completion of a state change.
576 #define GST_STATE_GET_COND(elem) (&GST_ELEMENT_CAST(elem)->state_cond)
578 #define GST_STATE_LOCK(elem) g_rec_mutex_lock(GST_STATE_GET_LOCK(elem))
579 #define GST_STATE_TRYLOCK(elem) g_rec_mutex_trylock(GST_STATE_GET_LOCK(elem))
580 #define GST_STATE_UNLOCK(elem) g_rec_mutex_unlock(GST_STATE_GET_LOCK(elem))
581 #define GST_STATE_WAIT(elem) g_cond_wait (GST_STATE_GET_COND (elem), \
582 GST_OBJECT_GET_LOCK (elem))
583 #define GST_STATE_WAIT_UNTIL(elem, end_time) g_cond_wait_until (GST_STATE_GET_COND (elem), \
584 GST_OBJECT_GET_LOCK (elem), end_time)
585 #define GST_STATE_SIGNAL(elem) g_cond_signal (GST_STATE_GET_COND (elem));
586 #define GST_STATE_BROADCAST(elem) g_cond_broadcast (GST_STATE_GET_COND (elem));
590 * @state_lock: Used to serialize execution of gst_element_set_state()
591 * @state_cond: Used to signal completion of a state change
592 * @state_cookie: Used to detect concurrent execution of
593 * gst_element_set_state() and gst_element_get_state()
594 * @target_state: the target state of an element as set by the application
595 * @current_state: the current state of an element
596 * @next_state: the next state of an element, can be #GST_STATE_VOID_PENDING if
597 * the element is in the correct state.
598 * @pending_state: the final state the element should go to, can be
599 * #GST_STATE_VOID_PENDING if the element is in the correct state
600 * @last_return: the last return value of an element state change
601 * @bus: the bus of the element. This bus is provided to the element by the
602 * parent element or the application. A #GstPipeline has a bus of its own.
603 * @clock: the clock of the element. This clock is usually provided to the
604 * element by the toplevel #GstPipeline.
605 * @base_time: the time of the clock right before the element is set to
606 * PLAYING. Subtracting @base_time from the current clock time in the PLAYING
607 * state will yield the running_time against the clock.
608 * @start_time: the running_time of the last PAUSED state
609 * @numpads: number of pads of the element, includes both source and sink pads.
610 * @pads: (element-type Gst.Pad): list of pads
611 * @numsrcpads: number of source pads of the element.
612 * @srcpads: (element-type Gst.Pad): list of source pads
613 * @numsinkpads: number of sink pads of the element.
614 * @sinkpads: (element-type Gst.Pad): list of sink pads
615 * @pads_cookie: updated whenever the a pad is added or removed
616 * @contexts: (element-type Gst.Context): list of contexts
618 * GStreamer element abstract base class.
624 /*< public >*/ /* with LOCK */
625 GRecMutex state_lock;
629 guint32 state_cookie;
630 GstState target_state;
631 GstState current_state;
633 GstState pending_state;
634 GstStateChangeReturn last_return;
638 /* allocated clock */
640 GstClockTimeDiff base_time; /* NULL/READY: 0 - PAUSED: current time - PLAYING: difference to clock */
641 GstClockTime start_time;
643 /* element pads, these lists can only be iterated while holding
644 * the LOCK or checking the cookie after each LOCK. */
653 /* with object LOCK */
657 gpointer _gst_reserved[GST_PADDING-1];
662 * @parent_class: the parent class structure
663 * @metadata: metadata for elements of this class
664 * @elementfactory: the #GstElementFactory that creates these elements
665 * @padtemplates: a #GList of #GstPadTemplate
666 * @numpadtemplates: the number of padtemplates
667 * @pad_templ_cookie: changed whenever the padtemplates change
668 * @request_new_pad: called when a new pad is requested
669 * @release_pad: called when a request pad is to be released
670 * @get_state: get the state of the element
671 * @set_state: set a new state on the element
672 * @change_state: called by @set_state to perform an incremental state change
673 * @set_bus: set a #GstBus on the element
674 * @provide_clock: gets the #GstClock provided by the element
675 * @set_clock: set the #GstClock on the element
676 * @send_event: send a #GstEvent to the element
677 * @query: perform a #GstQuery on the element
678 * @state_changed: called immediately after a new state was set.
679 * @post_message: called when a message is posted on the element. Chain up to
680 * the parent class' handler to have it posted on the bus.
681 * @set_context: set a #GstContext on the element
683 * GStreamer element class. Override the vmethods to implement the element
686 struct _GstElementClass
688 GstObjectClass parent_class;
691 /* the element metadata */
694 /* factory that the element was created from */
695 GstElementFactory *elementfactory;
697 /* templates for our pads */
699 gint numpadtemplates;
700 guint32 pad_templ_cookie;
703 /* signal callbacks */
704 void (*pad_added) (GstElement *element, GstPad *pad);
705 void (*pad_removed) (GstElement *element, GstPad *pad);
706 void (*no_more_pads) (GstElement *element);
709 /* virtual methods for subclasses */
711 /* request/release pads */
712 /* FIXME 2.0 harmonize naming with gst_element_request_pad */
713 GstPad* (*request_new_pad) (GstElement *element, GstPadTemplate *templ,
714 const gchar* name, const GstCaps *caps);
716 void (*release_pad) (GstElement *element, GstPad *pad);
719 GstStateChangeReturn (*get_state) (GstElement * element, GstState * state,
720 GstState * pending, GstClockTime timeout);
721 GstStateChangeReturn (*set_state) (GstElement *element, GstState state);
722 GstStateChangeReturn (*change_state) (GstElement *element, GstStateChange transition);
723 void (*state_changed) (GstElement *element, GstState oldstate,
724 GstState newstate, GstState pending);
727 void (*set_bus) (GstElement * element, GstBus * bus);
730 GstClock* (*provide_clock) (GstElement *element);
731 gboolean (*set_clock) (GstElement *element, GstClock *clock);
733 /* query functions */
734 gboolean (*send_event) (GstElement *element, GstEvent *event);
736 gboolean (*query) (GstElement *element, GstQuery *query);
738 gboolean (*post_message) (GstElement *element, GstMessage *message);
740 void (*set_context) (GstElement *element, GstContext *context);
743 gpointer _gst_reserved[GST_PADDING_LARGE-2];
746 /* element class pad templates */
747 void gst_element_class_add_pad_template (GstElementClass *klass, GstPadTemplate *templ);
749 void gst_element_class_add_static_pad_template (GstElementClass *klass, GstStaticPadTemplate *static_templ);
751 GstPadTemplate* gst_element_class_get_pad_template (GstElementClass *element_class, const gchar *name);
752 GList* gst_element_class_get_pad_template_list (GstElementClass *element_class);
754 /* element class meta data */
755 void gst_element_class_set_metadata (GstElementClass *klass,
756 const gchar *longname,
757 const gchar *classification,
758 const gchar *description,
759 const gchar *author);
760 void gst_element_class_set_static_metadata (GstElementClass *klass,
761 const gchar *longname,
762 const gchar *classification,
763 const gchar *description,
764 const gchar *author);
765 void gst_element_class_add_metadata (GstElementClass * klass,
766 const gchar * key, const gchar * value);
767 void gst_element_class_add_static_metadata (GstElementClass * klass,
768 const gchar * key, const gchar * value);
769 const gchar * gst_element_class_get_metadata (GstElementClass * klass,
773 /* element instance */
774 GType gst_element_get_type (void);
776 /* basic name and parentage stuff from GstObject */
779 * gst_element_get_name:
780 * @elem: a #GstElement to get the name of @elem.
782 * Returns a copy of the name of @elem.
783 * Caller should g_free() the return value after usage.
784 * For a nameless element, this returns %NULL, which you can safely g_free()
787 * Returns: (transfer full) (nullable): the name of @elem. g_free()
788 * after usage. MT safe.
791 #define gst_element_get_name(elem) gst_object_get_name(GST_OBJECT_CAST(elem))
794 * gst_element_set_name:
795 * @elem: a #GstElement to set the name of.
796 * @name: the new name
798 * Sets the name of the element, getting rid of the old name if there was one.
800 #define gst_element_set_name(elem,name) gst_object_set_name(GST_OBJECT_CAST(elem),name)
803 * gst_element_get_parent:
804 * @elem: a #GstElement to get the parent of.
806 * Get the parent of an element.
808 * Returns: (transfer full): the parent of an element.
810 #define gst_element_get_parent(elem) gst_object_get_parent(GST_OBJECT_CAST(elem))
813 * gst_element_set_parent:
814 * @elem: a #GstElement to set the parent of.
815 * @parent: the new parent #GstObject of the element.
817 * Sets the parent of an element.
819 #define gst_element_set_parent(elem,parent) gst_object_set_parent(GST_OBJECT_CAST(elem),parent)
822 GstClock* gst_element_provide_clock (GstElement *element);
823 GstClock* gst_element_get_clock (GstElement *element);
824 gboolean gst_element_set_clock (GstElement *element, GstClock *clock);
825 void gst_element_set_base_time (GstElement *element, GstClockTime time);
826 GstClockTime gst_element_get_base_time (GstElement *element);
827 void gst_element_set_start_time (GstElement *element, GstClockTime time);
828 GstClockTime gst_element_get_start_time (GstElement *element);
831 void gst_element_set_bus (GstElement * element, GstBus * bus);
832 GstBus * gst_element_get_bus (GstElement * element);
835 void gst_element_set_context (GstElement * element, GstContext * context);
836 GList * gst_element_get_contexts (GstElement * element);
837 GstContext * gst_element_get_context (GstElement * element, const gchar * context_type);
838 GstContext * gst_element_get_context_unlocked (GstElement * element, const gchar * context_type);
841 gboolean gst_element_add_pad (GstElement *element, GstPad *pad);
842 gboolean gst_element_remove_pad (GstElement *element, GstPad *pad);
843 void gst_element_no_more_pads (GstElement *element);
845 GstPad* gst_element_get_static_pad (GstElement *element, const gchar *name);
846 GstPad* gst_element_get_request_pad (GstElement *element, const gchar *name);
847 GstPad* gst_element_request_pad (GstElement *element, GstPadTemplate *templ,
848 const gchar * name, const GstCaps *caps);
849 void gst_element_release_request_pad (GstElement *element, GstPad *pad);
851 GstIterator * gst_element_iterate_pads (GstElement * element);
852 GstIterator * gst_element_iterate_src_pads (GstElement * element);
853 GstIterator * gst_element_iterate_sink_pads (GstElement * element);
855 /* event/query/format stuff */
856 gboolean gst_element_send_event (GstElement *element, GstEvent *event);
857 gboolean gst_element_seek (GstElement *element, gdouble rate,
858 GstFormat format, GstSeekFlags flags,
859 GstSeekType start_type, gint64 start,
860 GstSeekType stop_type, gint64 stop);
861 gboolean gst_element_query (GstElement *element, GstQuery *query);
864 gboolean gst_element_post_message (GstElement * element, GstMessage * message);
867 /* gcc versions < 3.3 warn about NULL being passed as format to printf */
868 #if (!defined(__GNUC__) || (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 3))
869 gchar * _gst_element_error_printf (const gchar *format, ...);
871 gchar * _gst_element_error_printf (const gchar *format, ...) G_GNUC_PRINTF (1, 2);
873 void gst_element_message_full (GstElement * element, GstMessageType type,
874 GQuark domain, gint code, gchar * text,
875 gchar * debug, const gchar * file,
876 const gchar * function, gint line);
878 void gst_element_message_full_with_details (GstElement * element, GstMessageType type,
879 GQuark domain, gint code, gchar * text,
880 gchar * debug, const gchar * file,
881 const gchar * function, gint line,
882 GstStructure * structure);
884 /* state management */
885 gboolean gst_element_is_locked_state (GstElement *element);
886 gboolean gst_element_set_locked_state (GstElement *element, gboolean locked_state);
887 gboolean gst_element_sync_state_with_parent (GstElement *element);
889 GstStateChangeReturn gst_element_get_state (GstElement * element,
892 GstClockTime timeout);
893 GstStateChangeReturn gst_element_set_state (GstElement *element, GstState state);
895 void gst_element_abort_state (GstElement * element);
896 GstStateChangeReturn gst_element_change_state (GstElement * element,
897 GstStateChange transition);
898 GstStateChangeReturn gst_element_continue_state (GstElement * element,
899 GstStateChangeReturn ret);
900 void gst_element_lost_state (GstElement * element);
902 typedef void (*GstElementCallAsyncFunc) (GstElement * element,
905 void gst_element_call_async (GstElement * element,
906 GstElementCallAsyncFunc func, gpointer user_data,
907 GDestroyNotify destroy_notify);
909 /* factory management */
910 GstElementFactory* gst_element_get_factory (GstElement *element);
912 /* utility functions */
913 gulong gst_element_add_property_notify_watch (GstElement * element,
914 const gchar * property_name,
915 gboolean include_value);
917 gulong gst_element_add_property_deep_notify_watch (GstElement * element,
918 const gchar * property_name,
919 gboolean include_value);
921 void gst_element_remove_property_notify_watch (GstElement * element,
924 #ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
925 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstElement, gst_object_unref)
930 #endif /* __GST_ELEMENT_H__ */