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.
182 * The element must check if the resources it needs are available. Device
183 * sinks and -sources typically try to probe the device to constrain their
187 * The element opens the device (in case feature need to be probed).
190 * @GST_STATE_CHANGE_READY_TO_PAUSED : state change from READY to PAUSED.
193 * The element pads are activated in order to receive data in PAUSED.
194 * Streaming threads are started.
197 * Some elements might need to return %GST_STATE_CHANGE_ASYNC and complete
198 * the state change when they have enough information. It is a requirement
199 * for sinks to return %GST_STATE_CHANGE_ASYNC and complete the state change
200 * when they receive the first buffer or %GST_EVENT_EOS (preroll).
201 * Sinks also block the dataflow when in PAUSED.
204 * A pipeline resets the running_time to 0.
207 * Live sources return %GST_STATE_CHANGE_NO_PREROLL and don't generate data.
210 * @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING.
213 * Most elements ignore this state change.
216 * The pipeline selects a #GstClock and distributes this to all the children
217 * before setting them to PLAYING. This means that it is only allowed to
218 * synchronize on the #GstClock in the PLAYING state.
221 * The pipeline uses the #GstClock and the running_time to calculate the
222 * base_time. The base_time is distributed to all children when performing
226 * Sink elements stop blocking on the preroll buffer or event and start
227 * rendering the data.
230 * Sinks can post %GST_MESSAGE_EOS in the PLAYING state. It is not allowed
231 * to post %GST_MESSAGE_EOS when not in the PLAYING state.
234 * While streaming in PAUSED or PLAYING elements can create and remove
238 * Live sources start generating data and return %GST_STATE_CHANGE_SUCCESS.
241 * @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED.
244 * Most elements ignore this state change.
247 * The pipeline calculates the running_time based on the last selected
248 * #GstClock and the base_time. It stores this information to continue
249 * playback when going back to the PLAYING state.
252 * Sinks unblock any #GstClock wait calls.
255 * When a sink does not have a pending buffer to play, it returns
256 * %GST_STATE_CHANGE_ASYNC from this state change and completes the state
257 * change when it receives a new buffer or an %GST_EVENT_EOS.
260 * Any queued %GST_MESSAGE_EOS items are removed since they will be reposted
261 * when going back to the PLAYING state. The EOS messages are queued in
262 * #GstBin containers.
265 * Live sources stop generating data and return %GST_STATE_CHANGE_NO_PREROLL.
268 * @GST_STATE_CHANGE_PAUSED_TO_READY : state change from PAUSED to READY.
271 * Sinks unblock any waits in the preroll.
274 * Elements unblock any waits on devices
277 * Chain or get_range functions return %GST_FLOW_FLUSHING.
280 * The element pads are deactivated so that streaming becomes impossible and
281 * all streaming threads are stopped.
284 * The sink forgets all negotiated formats
287 * Elements remove all sometimes pads
290 * @GST_STATE_CHANGE_READY_TO_NULL : state change from READY to NULL.
293 * Elements close devices
296 * Elements reset any internal state.
300 * These are the different state changes an element goes through.
301 * %GST_STATE_NULL ⇒ %GST_STATE_PLAYING is called an upwards state change
302 * and %GST_STATE_PLAYING ⇒ %GST_STATE_NULL a downwards state change.
304 typedef enum /*< flags=0 >*/
306 GST_STATE_CHANGE_NULL_TO_READY = (GST_STATE_NULL<<3) | GST_STATE_READY,
307 GST_STATE_CHANGE_READY_TO_PAUSED = (GST_STATE_READY<<3) | GST_STATE_PAUSED,
308 GST_STATE_CHANGE_PAUSED_TO_PLAYING = (GST_STATE_PAUSED<<3) | GST_STATE_PLAYING,
309 GST_STATE_CHANGE_PLAYING_TO_PAUSED = (GST_STATE_PLAYING<<3) | GST_STATE_PAUSED,
310 GST_STATE_CHANGE_PAUSED_TO_READY = (GST_STATE_PAUSED<<3) | GST_STATE_READY,
311 GST_STATE_CHANGE_READY_TO_NULL = (GST_STATE_READY<<3) | GST_STATE_NULL
316 * @GST_ELEMENT_FLAG_LOCKED_STATE: ignore state changes from parent
317 * @GST_ELEMENT_FLAG_SINK: the element is a sink
318 * @GST_ELEMENT_FLAG_SOURCE: the element is a source.
319 * @GST_ELEMENT_FLAG_PROVIDE_CLOCK: the element can provide a clock
320 * @GST_ELEMENT_FLAG_REQUIRE_CLOCK: the element requires a clock
321 * @GST_ELEMENT_FLAG_INDEXABLE: the element can use an index
322 * @GST_ELEMENT_FLAG_LAST: offset to define more flags
324 * The standard flags that an element may have.
328 GST_ELEMENT_FLAG_LOCKED_STATE = (GST_OBJECT_FLAG_LAST << 0),
329 GST_ELEMENT_FLAG_SINK = (GST_OBJECT_FLAG_LAST << 1),
330 GST_ELEMENT_FLAG_SOURCE = (GST_OBJECT_FLAG_LAST << 2),
331 GST_ELEMENT_FLAG_PROVIDE_CLOCK = (GST_OBJECT_FLAG_LAST << 3),
332 GST_ELEMENT_FLAG_REQUIRE_CLOCK = (GST_OBJECT_FLAG_LAST << 4),
333 GST_ELEMENT_FLAG_INDEXABLE = (GST_OBJECT_FLAG_LAST << 5),
335 GST_ELEMENT_FLAG_LAST = (GST_OBJECT_FLAG_LAST << 10)
339 * GST_ELEMENT_IS_LOCKED_STATE:
340 * @elem: A #GstElement to query
342 * Check if the element is in the locked state and therefore will ignore state
343 * changes from its parent object.
345 #define GST_ELEMENT_IS_LOCKED_STATE(elem) (GST_OBJECT_FLAG_IS_SET(elem,GST_ELEMENT_FLAG_LOCKED_STATE))
349 * @elem: A #GstElement to query
351 * Gets the name of this element. This is not thread-safe by default
352 * (i.e. you will have to make sure the object lock is taken yourself).
353 * If in doubt use gst_element_get_name() instead.
355 #define GST_ELEMENT_NAME(elem) (GST_OBJECT_NAME(elem))
358 * GST_ELEMENT_PARENT:
359 * @elem: A #GstElement to query
361 * Get the parent object of this element. This is not thread-safe by default
362 * (i.e. you will have to make sure the object lock is taken yourself).
363 * If in doubt use gst_object_get_parent() instead.
365 #define GST_ELEMENT_PARENT(elem) (GST_ELEMENT_CAST(GST_OBJECT_PARENT(elem)))
369 * @elem: A #GstElement to query
371 * Get the message bus of this element. This is not thread-safe by default
372 * (i.e. you will have to make sure the object lock is taken yourself).
373 * If in doubt use gst_element_get_bus() instead.
375 #define GST_ELEMENT_BUS(elem) (GST_ELEMENT_CAST(elem)->bus)
379 * @elem: A #GstElement to query
381 * Get the clock of this element.This is not thread-safe by default
382 * (i.e. you will have to make sure it is safe yourself).
383 * If in doubt use gst_element_get_clock() instead.
385 #define GST_ELEMENT_CLOCK(elem) (GST_ELEMENT_CAST(elem)->clock)
389 * @elem: A #GstElement to query
391 * Get the pads of this elements.
393 #define GST_ELEMENT_PADS(elem) (GST_ELEMENT_CAST(elem)->pads)
396 * GST_ELEMENT_START_TIME:
397 * @elem: a #GstElement to return the start time for.
399 * This macro returns the start_time of the @elem. The start_time is the
400 * running_time of the pipeline when the element went to PAUSED.
402 #define GST_ELEMENT_START_TIME(elem) (GST_ELEMENT_CAST(elem)->start_time)
404 GstStructure *gst_make_element_message_details (const char *name, ...);
405 #define GST_ELEMENT_MESSAGE_MAKE_DETAILS(args) gst_make_element_message_details args
408 * GST_ELEMENT_FLOW_ERROR:
409 * @el: the element that generates the error
410 * @flow_return: the GstFlowReturn leading to that ERROR message
412 * Utility function that elements can use in case they encountered a fatal
413 * data processing error due to wrong flow processing.
417 #define GST_ELEMENT_FLOW_ERROR(el,flow_return) \
419 GST_ELEMENT_ERROR_WITH_DETAILS (el, STREAM, FAILED, \
420 ("Internal data stream error."), \
421 ("streaming stopped, reason %s (%d)", gst_flow_get_name (flow_return), flow_return), \
422 ("flow-return", G_TYPE_INT, flow_return, NULL));\
426 * GST_ELEMENT_ERROR_WITH_DETAILS:
427 * @el: the element that generates the error
428 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
429 * @code: error code defined for that domain (see #gstreamer-GstGError)
430 * @text: the message to display (format string and args enclosed in
432 * @debug: debugging information for the message (format string and args
433 enclosed in parentheses)
434 * @args: optional name, type, value triplets, which will be stored
435 * in the associated GstStructure. NULL terminator required.
436 * Must be enclosed within parentheses.
438 * Utility function that elements can use in case they encountered a fatal
439 * data processing error. The pipeline will post an error message and the
440 * application will be requested to stop further media processing.
444 #define GST_ELEMENT_ERROR_WITH_DETAILS(el,domain,code,text,debug,args) \
446 gchar *__txt = _gst_element_error_printf text; \
447 gchar *__dbg = _gst_element_error_printf debug; \
449 GST_WARNING_OBJECT (el, "error: %s", __txt); \
451 GST_WARNING_OBJECT (el, "error: %s", __dbg); \
452 gst_element_message_full_with_details (GST_ELEMENT(el), \
453 GST_MESSAGE_ERROR, GST_ ## domain ## _ERROR, \
454 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
455 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
460 * @el: the element that generates the error
461 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
462 * @code: error code defined for that domain (see #gstreamer-GstGError)
463 * @text: the message to display (format string and args enclosed in
465 * @debug: debugging information for the message (format string and args
466 enclosed in parentheses)
468 * Utility function that elements can use in case they encountered a fatal
469 * data processing error. The pipeline will post an error message and the
470 * application will be requested to stop further media processing.
472 #define GST_ELEMENT_ERROR(el,domain,code,text,debug) \
474 gchar *__txt = _gst_element_error_printf text; \
475 gchar *__dbg = _gst_element_error_printf debug; \
477 GST_WARNING_OBJECT (el, "error: %s", __txt); \
479 GST_WARNING_OBJECT (el, "error: %s", __dbg); \
480 gst_element_message_full (GST_ELEMENT(el), \
481 GST_MESSAGE_ERROR, GST_ ## domain ## _ERROR, \
482 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
483 GST_FUNCTION, __LINE__); \
487 * GST_ELEMENT_WARNING_WITH_DETAILS:
488 * @el: the element that generates the warning
489 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
490 * @code: error code defined for that domain (see #gstreamer-GstGError)
491 * @text: the message to display (format string and args enclosed in
493 * @debug: debugging information for the message (format string and args
494 enclosed in parentheses)
495 * @args: optional name, type, value triplets, which will be stored
496 * in the associated GstStructure. NULL terminator required.
497 * Must be enclosed within parentheses.
499 * Utility function that elements can use in case they encountered a non-fatal
500 * data processing problem. The pipeline will post a warning message and the
501 * application will be informed.
505 #define GST_ELEMENT_WARNING_WITH_DETAILS(el, domain, code, text, debug, args)\
507 gchar *__txt = _gst_element_error_printf text; \
508 gchar *__dbg = _gst_element_error_printf debug; \
510 GST_WARNING_OBJECT (el, "warning: %s", __txt); \
512 GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
513 gst_element_message_full_with_details (GST_ELEMENT(el), \
514 GST_MESSAGE_WARNING, GST_ ## domain ## _ERROR, \
515 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
516 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
520 * GST_ELEMENT_WARNING:
521 * @el: the element that generates the warning
522 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
523 * @code: error code defined for that domain (see #gstreamer-GstGError)
524 * @text: the message to display (format string and args enclosed in
526 * @debug: debugging information for the message (format string and args
527 enclosed in parentheses)
529 * Utility function that elements can use in case they encountered a non-fatal
530 * data processing problem. The pipeline will post a warning message and the
531 * application will be informed.
533 #define GST_ELEMENT_WARNING(el, domain, code, text, debug) \
535 gchar *__txt = _gst_element_error_printf text; \
536 gchar *__dbg = _gst_element_error_printf debug; \
538 GST_WARNING_OBJECT (el, "warning: %s", __txt); \
540 GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
541 gst_element_message_full (GST_ELEMENT(el), \
542 GST_MESSAGE_WARNING, GST_ ## domain ## _ERROR, \
543 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
544 GST_FUNCTION, __LINE__); \
548 * GST_ELEMENT_INFO_WITH_DETAILS:
549 * @el: the element that generates the information
550 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
551 * @code: error code defined for that domain (see #gstreamer-GstGError)
552 * @text: the message to display (format string and args enclosed in
554 * @debug: debugging information for the message (format string and args
555 enclosed in parentheses)
556 * @args: optional name, type, value triplets, which will be stored
557 * in the associated GstStructure. NULL terminator required.
558 * Must be enclosed within parentheses.
560 * Utility function that elements can use in case they want to inform
561 * the application of something noteworthy that is not an error.
562 * The pipeline will post a info message and the
563 * application will be informed.
564 * Optional name, type, value triplets may be supplied, and will be stored
565 * in the associated GstStructure. NULL terminator required.
569 #define GST_ELEMENT_INFO_WITH_DETAILS(el, domain, code, text, debug, args) \
571 gchar *__txt = _gst_element_error_printf text; \
572 gchar *__dbg = _gst_element_error_printf debug; \
574 GST_INFO_OBJECT (el, "info: %s", __txt); \
576 GST_INFO_OBJECT (el, "info: %s", __dbg); \
577 gst_element_message_full_with_details (GST_ELEMENT(el), \
578 GST_MESSAGE_INFO, GST_ ## domain ## _ERROR, \
579 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
580 GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args)); \
585 * @el: the element that generates the information
586 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
587 * @code: error code defined for that domain (see #gstreamer-GstGError)
588 * @text: the message to display (format string and args enclosed in
590 * @debug: debugging information for the message (format string and args
591 enclosed in parentheses)
593 * Utility function that elements can use in case they want to inform
594 * the application of something noteworthy that is not an error.
595 * The pipeline will post a info message and the
596 * application will be informed.
598 #define GST_ELEMENT_INFO(el, domain, code, text, debug) \
600 gchar *__txt = _gst_element_error_printf text; \
601 gchar *__dbg = _gst_element_error_printf debug; \
603 GST_INFO_OBJECT (el, "info: %s", __txt); \
605 GST_INFO_OBJECT (el, "info: %s", __dbg); \
606 gst_element_message_full (GST_ELEMENT(el), \
607 GST_MESSAGE_INFO, GST_ ## domain ## _ERROR, \
608 GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__, \
609 GST_FUNCTION, __LINE__); \
612 /* the state change mutexes and conds */
614 * GST_STATE_GET_LOCK:
615 * @elem: a #GstElement
617 * Get a reference to the state lock of @elem.
618 * This lock is used by the core. It is taken while getting or setting
619 * the state, during state changes, and while finalizing.
621 #define GST_STATE_GET_LOCK(elem) (&(GST_ELEMENT_CAST(elem)->state_lock))
623 * GST_STATE_GET_COND:
624 * @elem: a #GstElement
626 * Get the conditional used to signal the completion of a state change.
628 #define GST_STATE_GET_COND(elem) (&GST_ELEMENT_CAST(elem)->state_cond)
630 #define GST_STATE_LOCK(elem) g_rec_mutex_lock(GST_STATE_GET_LOCK(elem))
631 #define GST_STATE_TRYLOCK(elem) g_rec_mutex_trylock(GST_STATE_GET_LOCK(elem))
632 #define GST_STATE_UNLOCK(elem) g_rec_mutex_unlock(GST_STATE_GET_LOCK(elem))
633 #define GST_STATE_WAIT(elem) g_cond_wait (GST_STATE_GET_COND (elem), \
634 GST_OBJECT_GET_LOCK (elem))
635 #define GST_STATE_WAIT_UNTIL(elem, end_time) g_cond_wait_until (GST_STATE_GET_COND (elem), \
636 GST_OBJECT_GET_LOCK (elem), end_time)
637 #define GST_STATE_SIGNAL(elem) g_cond_signal (GST_STATE_GET_COND (elem));
638 #define GST_STATE_BROADCAST(elem) g_cond_broadcast (GST_STATE_GET_COND (elem));
642 * @state_lock: Used to serialize execution of gst_element_set_state()
643 * @state_cond: Used to signal completion of a state change
644 * @state_cookie: Used to detect concurrent execution of
645 * gst_element_set_state() and gst_element_get_state()
646 * @target_state: the target state of an element as set by the application
647 * @current_state: the current state of an element
648 * @next_state: the next state of an element, can be #GST_STATE_VOID_PENDING if
649 * the element is in the correct state.
650 * @pending_state: the final state the element should go to, can be
651 * #GST_STATE_VOID_PENDING if the element is in the correct state
652 * @last_return: the last return value of an element state change
653 * @bus: the bus of the element. This bus is provided to the element by the
654 * parent element or the application. A #GstPipeline has a bus of its own.
655 * @clock: the clock of the element. This clock is usually provided to the
656 * element by the toplevel #GstPipeline.
657 * @base_time: the time of the clock right before the element is set to
658 * PLAYING. Subtracting @base_time from the current clock time in the PLAYING
659 * state will yield the running_time against the clock.
660 * @start_time: the running_time of the last PAUSED state
661 * @numpads: number of pads of the element, includes both source and sink pads.
662 * @pads: (element-type Gst.Pad): list of pads
663 * @numsrcpads: number of source pads of the element.
664 * @srcpads: (element-type Gst.Pad): list of source pads
665 * @numsinkpads: number of sink pads of the element.
666 * @sinkpads: (element-type Gst.Pad): list of sink pads
667 * @pads_cookie: updated whenever the a pad is added or removed
668 * @contexts: (element-type Gst.Context): list of contexts
670 * GStreamer element abstract base class.
676 /*< public >*/ /* with LOCK */
677 GRecMutex state_lock;
681 guint32 state_cookie;
682 GstState target_state;
683 GstState current_state;
685 GstState pending_state;
686 GstStateChangeReturn last_return;
690 /* allocated clock */
692 GstClockTimeDiff base_time; /* NULL/READY: 0 - PAUSED: current time - PLAYING: difference to clock */
693 GstClockTime start_time;
695 /* element pads, these lists can only be iterated while holding
696 * the LOCK or checking the cookie after each LOCK. */
705 /* with object LOCK */
709 gpointer _gst_reserved[GST_PADDING-1];
714 * @parent_class: the parent class structure
715 * @metadata: metadata for elements of this class
716 * @elementfactory: the #GstElementFactory that creates these elements
717 * @padtemplates: a #GList of #GstPadTemplate
718 * @numpadtemplates: the number of padtemplates
719 * @pad_templ_cookie: changed whenever the padtemplates change
720 * @request_new_pad: called when a new pad is requested
721 * @release_pad: called when a request pad is to be released
722 * @get_state: get the state of the element
723 * @set_state: set a new state on the element
724 * @change_state: called by @set_state to perform an incremental state change
725 * @set_bus: set a #GstBus on the element
726 * @provide_clock: gets the #GstClock provided by the element
727 * @set_clock: set the #GstClock on the element
728 * @send_event: send a #GstEvent to the element
729 * @query: perform a #GstQuery on the element
730 * @state_changed: called immediately after a new state was set.
731 * @post_message: called when a message is posted on the element. Chain up to
732 * the parent class' handler to have it posted on the bus.
733 * @set_context: set a #GstContext on the element
735 * GStreamer element class. Override the vmethods to implement the element
738 struct _GstElementClass
740 GstObjectClass parent_class;
743 /* the element metadata */
746 /* factory that the element was created from */
747 GstElementFactory *elementfactory;
749 /* templates for our pads */
751 gint numpadtemplates;
752 guint32 pad_templ_cookie;
755 /* signal callbacks */
756 void (*pad_added) (GstElement *element, GstPad *pad);
757 void (*pad_removed) (GstElement *element, GstPad *pad);
758 void (*no_more_pads) (GstElement *element);
761 /* virtual methods for subclasses */
763 /* request/release pads */
764 /* FIXME 2.0 harmonize naming with gst_element_request_pad */
765 GstPad* (*request_new_pad) (GstElement *element, GstPadTemplate *templ,
766 const gchar* name, const GstCaps *caps);
768 void (*release_pad) (GstElement *element, GstPad *pad);
771 GstStateChangeReturn (*get_state) (GstElement * element, GstState * state,
772 GstState * pending, GstClockTime timeout);
773 GstStateChangeReturn (*set_state) (GstElement *element, GstState state);
774 GstStateChangeReturn (*change_state) (GstElement *element, GstStateChange transition);
775 void (*state_changed) (GstElement *element, GstState oldstate,
776 GstState newstate, GstState pending);
779 void (*set_bus) (GstElement * element, GstBus * bus);
782 GstClock* (*provide_clock) (GstElement *element);
783 gboolean (*set_clock) (GstElement *element, GstClock *clock);
785 /* query functions */
786 gboolean (*send_event) (GstElement *element, GstEvent *event);
788 gboolean (*query) (GstElement *element, GstQuery *query);
790 gboolean (*post_message) (GstElement *element, GstMessage *message);
792 void (*set_context) (GstElement *element, GstContext *context);
795 gpointer _gst_reserved[GST_PADDING_LARGE-2];
798 /* element class pad templates */
799 void gst_element_class_add_pad_template (GstElementClass *klass, GstPadTemplate *templ);
801 void gst_element_class_add_static_pad_template (GstElementClass *klass, GstStaticPadTemplate *static_templ);
803 GstPadTemplate* gst_element_class_get_pad_template (GstElementClass *element_class, const gchar *name);
804 GList* gst_element_class_get_pad_template_list (GstElementClass *element_class);
806 /* element class meta data */
807 void gst_element_class_set_metadata (GstElementClass *klass,
808 const gchar *longname,
809 const gchar *classification,
810 const gchar *description,
811 const gchar *author);
812 void gst_element_class_set_static_metadata (GstElementClass *klass,
813 const gchar *longname,
814 const gchar *classification,
815 const gchar *description,
816 const gchar *author);
817 void gst_element_class_add_metadata (GstElementClass * klass,
818 const gchar * key, const gchar * value);
819 void gst_element_class_add_static_metadata (GstElementClass * klass,
820 const gchar * key, const gchar * value);
821 const gchar * gst_element_class_get_metadata (GstElementClass * klass,
825 /* element instance */
826 GType gst_element_get_type (void);
828 /* basic name and parentage stuff from GstObject */
831 * gst_element_get_name:
832 * @elem: a #GstElement to get the name of @elem.
834 * Returns a copy of the name of @elem.
835 * Caller should g_free() the return value after usage.
836 * For a nameless element, this returns %NULL, which you can safely g_free()
839 * Returns: (transfer full) (nullable): the name of @elem. g_free()
840 * after usage. MT safe.
843 #define gst_element_get_name(elem) gst_object_get_name(GST_OBJECT_CAST(elem))
846 * gst_element_set_name:
847 * @elem: a #GstElement to set the name of.
848 * @name: the new name
850 * Sets the name of the element, getting rid of the old name if there was one.
852 #define gst_element_set_name(elem,name) gst_object_set_name(GST_OBJECT_CAST(elem),name)
855 * gst_element_get_parent:
856 * @elem: a #GstElement to get the parent of.
858 * Get the parent of an element.
860 * Returns: (transfer full): the parent of an element.
862 #define gst_element_get_parent(elem) gst_object_get_parent(GST_OBJECT_CAST(elem))
865 * gst_element_set_parent:
866 * @elem: a #GstElement to set the parent of.
867 * @parent: the new parent #GstObject of the element.
869 * Sets the parent of an element.
871 #define gst_element_set_parent(elem,parent) gst_object_set_parent(GST_OBJECT_CAST(elem),parent)
874 GstClock* gst_element_provide_clock (GstElement *element);
875 GstClock* gst_element_get_clock (GstElement *element);
876 gboolean gst_element_set_clock (GstElement *element, GstClock *clock);
877 void gst_element_set_base_time (GstElement *element, GstClockTime time);
878 GstClockTime gst_element_get_base_time (GstElement *element);
879 void gst_element_set_start_time (GstElement *element, GstClockTime time);
880 GstClockTime gst_element_get_start_time (GstElement *element);
883 void gst_element_set_bus (GstElement * element, GstBus * bus);
884 GstBus * gst_element_get_bus (GstElement * element);
887 void gst_element_set_context (GstElement * element, GstContext * context);
888 GList * gst_element_get_contexts (GstElement * element);
889 GstContext * gst_element_get_context (GstElement * element, const gchar * context_type);
890 GstContext * gst_element_get_context_unlocked (GstElement * element, const gchar * context_type);
893 gboolean gst_element_add_pad (GstElement *element, GstPad *pad);
894 gboolean gst_element_remove_pad (GstElement *element, GstPad *pad);
895 void gst_element_no_more_pads (GstElement *element);
897 GstPad* gst_element_get_static_pad (GstElement *element, const gchar *name);
898 GstPad* gst_element_get_request_pad (GstElement *element, const gchar *name);
899 GstPad* gst_element_request_pad (GstElement *element, GstPadTemplate *templ,
900 const gchar * name, const GstCaps *caps);
901 void gst_element_release_request_pad (GstElement *element, GstPad *pad);
903 GstIterator * gst_element_iterate_pads (GstElement * element);
904 GstIterator * gst_element_iterate_src_pads (GstElement * element);
905 GstIterator * gst_element_iterate_sink_pads (GstElement * element);
907 /* event/query/format stuff */
908 gboolean gst_element_send_event (GstElement *element, GstEvent *event);
909 gboolean gst_element_seek (GstElement *element, gdouble rate,
910 GstFormat format, GstSeekFlags flags,
911 GstSeekType start_type, gint64 start,
912 GstSeekType stop_type, gint64 stop);
913 gboolean gst_element_query (GstElement *element, GstQuery *query);
916 gboolean gst_element_post_message (GstElement * element, GstMessage * message);
919 /* gcc versions < 3.3 warn about NULL being passed as format to printf */
920 #if (!defined(__GNUC__) || (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 3))
921 gchar * _gst_element_error_printf (const gchar *format, ...);
923 gchar * _gst_element_error_printf (const gchar *format, ...) G_GNUC_PRINTF (1, 2);
925 void gst_element_message_full (GstElement * element, GstMessageType type,
926 GQuark domain, gint code, gchar * text,
927 gchar * debug, const gchar * file,
928 const gchar * function, gint line);
930 void gst_element_message_full_with_details (GstElement * element, GstMessageType type,
931 GQuark domain, gint code, gchar * text,
932 gchar * debug, const gchar * file,
933 const gchar * function, gint line,
934 GstStructure * structure);
936 /* state management */
937 gboolean gst_element_is_locked_state (GstElement *element);
938 gboolean gst_element_set_locked_state (GstElement *element, gboolean locked_state);
939 gboolean gst_element_sync_state_with_parent (GstElement *element);
941 GstStateChangeReturn gst_element_get_state (GstElement * element,
944 GstClockTime timeout);
945 GstStateChangeReturn gst_element_set_state (GstElement *element, GstState state);
947 void gst_element_abort_state (GstElement * element);
948 GstStateChangeReturn gst_element_change_state (GstElement * element,
949 GstStateChange transition);
950 GstStateChangeReturn gst_element_continue_state (GstElement * element,
951 GstStateChangeReturn ret);
952 void gst_element_lost_state (GstElement * element);
954 typedef void (*GstElementCallAsyncFunc) (GstElement * element,
957 void gst_element_call_async (GstElement * element,
958 GstElementCallAsyncFunc func, gpointer user_data,
959 GDestroyNotify destroy_notify);
961 /* factory management */
962 GstElementFactory* gst_element_get_factory (GstElement *element);
964 /* utility functions */
965 gulong gst_element_add_property_notify_watch (GstElement * element,
966 const gchar * property_name,
967 gboolean include_value);
969 gulong gst_element_add_property_deep_notify_watch (GstElement * element,
970 const gchar * property_name,
971 gboolean include_value);
973 void gst_element_remove_property_notify_watch (GstElement * element,
976 #ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
977 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstElement, gst_object_unref)
982 #endif /* __GST_ELEMENT_H__ */