2 * Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
4 * gstmessage.c: GstMessage subsystem
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
24 * @short_description: Lightweight objects to signal the application of
26 * @see_also: #GstBus, #GstMiniObject, #GstElement
28 * Messages are implemented as a subclass of #GstMiniObject with a generic
29 * #GstStructure as the content. This allows for writing custom messages without
30 * requiring an API change while allowing a wide range of different types
33 * Messages are posted by objects in the pipeline and are passed to the
34 * application using the #GstBus.
36 * The basic use pattern of posting a message on a #GstBus is as follows:
39 * <title>Posting a #GstMessage</title>
41 * gst_bus_post (bus, gst_message_new_eos());
45 * A #GstElement usually posts messages on the bus provided by the parent
46 * container using gst_element_post_message().
48 * Last reviewed on 2005-11-09 (0.9.4)
52 #include "gst_private.h"
53 #include <string.h> /* memcpy */
55 #include "gstenumtypes.h"
57 #include "gstmessage.h"
58 #include "gsttaglist.h"
67 GstStructure *structure;
70 #define GST_MESSAGE_STRUCTURE(m) (((GstMessageImpl *)(m))->structure)
79 static GstMessageQuarks message_quarks[] = {
80 {GST_MESSAGE_UNKNOWN, "unknown", 0},
81 {GST_MESSAGE_EOS, "eos", 0},
82 {GST_MESSAGE_ERROR, "error", 0},
83 {GST_MESSAGE_WARNING, "warning", 0},
84 {GST_MESSAGE_INFO, "info", 0},
85 {GST_MESSAGE_TAG, "tag", 0},
86 {GST_MESSAGE_BUFFERING, "buffering", 0},
87 {GST_MESSAGE_STATE_CHANGED, "state-changed", 0},
88 {GST_MESSAGE_STATE_DIRTY, "state-dirty", 0},
89 {GST_MESSAGE_STEP_DONE, "step-done", 0},
90 {GST_MESSAGE_CLOCK_PROVIDE, "clock-provide", 0},
91 {GST_MESSAGE_CLOCK_LOST, "clock-lost", 0},
92 {GST_MESSAGE_NEW_CLOCK, "new-clock", 0},
93 {GST_MESSAGE_STRUCTURE_CHANGE, "structure-change", 0},
94 {GST_MESSAGE_STREAM_STATUS, "stream-status", 0},
95 {GST_MESSAGE_APPLICATION, "application", 0},
96 {GST_MESSAGE_ELEMENT, "element", 0},
97 {GST_MESSAGE_SEGMENT_START, "segment-start", 0},
98 {GST_MESSAGE_SEGMENT_DONE, "segment-done", 0},
99 {GST_MESSAGE_DURATION, "duration", 0},
100 {GST_MESSAGE_LATENCY, "latency", 0},
101 {GST_MESSAGE_ASYNC_START, "async-start", 0},
102 {GST_MESSAGE_ASYNC_DONE, "async-done", 0},
103 {GST_MESSAGE_REQUEST_STATE, "request-state", 0},
104 {GST_MESSAGE_STEP_START, "step-start", 0},
105 {GST_MESSAGE_QOS, "qos", 0},
106 {GST_MESSAGE_PROGRESS, "progress", 0},
107 {GST_MESSAGE_TOC, "toc", 0},
108 {GST_MESSAGE_STREAM_START, "stream-start", 0},
112 static GType _gst_message_type = 0;
113 GST_DEFINE_MINI_OBJECT_TYPE (GstMessage, gst_message);
116 _priv_gst_message_initialize (void)
120 GST_CAT_INFO (GST_CAT_GST_INIT, "init messages");
122 /* the GstMiniObject types need to be class_ref'd once before it can be
123 * done from multiple threads;
124 * see http://bugzilla.gnome.org/show_bug.cgi?id=304551 */
125 gst_message_get_type ();
127 for (i = 0; message_quarks[i].name; i++) {
128 message_quarks[i].quark =
129 g_quark_from_static_string (message_quarks[i].name);
132 _gst_message_type = gst_message_get_type ();
136 * gst_message_type_get_name:
137 * @type: the message type
139 * Get a printable name for the given message type. Do not modify or free.
141 * Returns: a reference to the static name of the message.
144 gst_message_type_get_name (GstMessageType type)
148 for (i = 0; message_quarks[i].name; i++) {
149 if (type == message_quarks[i].type)
150 return message_quarks[i].name;
156 * gst_message_type_to_quark:
157 * @type: the message type
159 * Get the unique quark for the given message type.
161 * Returns: the quark associated with the message type
164 gst_message_type_to_quark (GstMessageType type)
168 for (i = 0; message_quarks[i].name; i++) {
169 if (type == message_quarks[i].type)
170 return message_quarks[i].quark;
176 _gst_message_free (GstMessage * message)
178 GstStructure *structure;
180 g_return_if_fail (message != NULL);
182 GST_CAT_LOG (GST_CAT_MESSAGE, "finalize message %p, %s from %s", message,
183 GST_MESSAGE_TYPE_NAME (message), GST_MESSAGE_SRC_NAME (message));
185 if (GST_MESSAGE_SRC (message)) {
186 gst_object_unref (GST_MESSAGE_SRC (message));
187 GST_MESSAGE_SRC (message) = NULL;
190 if (message->lock.p) {
191 GST_MESSAGE_LOCK (message);
192 GST_MESSAGE_SIGNAL (message);
193 GST_MESSAGE_UNLOCK (message);
196 structure = GST_MESSAGE_STRUCTURE (message);
198 gst_structure_set_parent_refcount (structure, NULL);
199 gst_structure_free (structure);
202 g_slice_free1 (sizeof (GstMessageImpl), message);
206 gst_message_init (GstMessageImpl * message, GstMessageType type,
210 _gst_message_copy (GstMessage * message)
212 GstMessageImpl *copy;
213 GstStructure *structure;
215 GST_CAT_LOG (GST_CAT_MESSAGE, "copy message %p, %s from %s", message,
216 GST_MESSAGE_TYPE_NAME (message),
217 GST_OBJECT_NAME (GST_MESSAGE_SRC (message)));
219 copy = g_slice_new0 (GstMessageImpl);
221 gst_message_init (copy, GST_MESSAGE_TYPE (message),
222 GST_MESSAGE_SRC (message));
224 GST_MESSAGE_TIMESTAMP (copy) = GST_MESSAGE_TIMESTAMP (message);
225 GST_MESSAGE_SEQNUM (copy) = GST_MESSAGE_SEQNUM (message);
227 structure = GST_MESSAGE_STRUCTURE (message);
229 GST_MESSAGE_STRUCTURE (copy) = gst_structure_copy (structure);
230 gst_structure_set_parent_refcount (GST_MESSAGE_STRUCTURE (copy),
231 ©->message.mini_object.refcount);
233 GST_MESSAGE_STRUCTURE (copy) = NULL;
236 return GST_MESSAGE_CAST (copy);
240 gst_message_init (GstMessageImpl * message, GstMessageType type,
243 gst_mini_object_init (GST_MINI_OBJECT_CAST (message), 0, _gst_message_type,
244 (GstMiniObjectCopyFunction) _gst_message_copy, NULL,
245 (GstMiniObjectFreeFunction) _gst_message_free);
247 GST_MESSAGE_TYPE (message) = type;
249 gst_object_ref (src);
250 GST_MESSAGE_SRC (message) = src;
251 GST_MESSAGE_TIMESTAMP (message) = GST_CLOCK_TIME_NONE;
252 GST_MESSAGE_SEQNUM (message) = gst_util_seqnum_next ();
257 * gst_message_new_custom:
258 * @type: The #GstMessageType to distinguish messages
259 * @src: The object originating the message.
260 * @structure: (transfer full): the structure for the message. The message
261 * will take ownership of the structure.
263 * Create a new custom-typed message. This can be used for anything not
264 * handled by other message-specific functions to pass a message to the
265 * app. The structure field can be NULL.
267 * Returns: (transfer full): The new message.
272 gst_message_new_custom (GstMessageType type, GstObject * src,
273 GstStructure * structure)
275 GstMessageImpl *message;
277 message = g_slice_new0 (GstMessageImpl);
279 GST_CAT_LOG (GST_CAT_MESSAGE, "source %s: creating new message %p %s",
280 (src ? GST_OBJECT_NAME (src) : "NULL"), message,
281 gst_message_type_get_name (type));
284 /* structure must not have a parent */
285 if (!gst_structure_set_parent_refcount (structure,
286 &message->message.mini_object.refcount))
289 gst_message_init (message, type, src);
291 GST_MESSAGE_STRUCTURE (message) = structure;
293 return GST_MESSAGE_CAST (message);
298 g_slice_free1 (sizeof (GstMessageImpl), message);
299 g_warning ("structure is already owned by another object");
305 * gst_message_get_seqnum:
306 * @message: A #GstMessage.
308 * Retrieve the sequence number of a message.
310 * Messages have ever-incrementing sequence numbers, which may also be set
311 * explicitly via gst_message_set_seqnum(). Sequence numbers are typically used
312 * to indicate that a message corresponds to some other set of messages or
313 * events, for example a SEGMENT_DONE message corresponding to a SEEK event. It
314 * is considered good practice to make this correspondence when possible, though
315 * it is not required.
317 * Note that events and messages share the same sequence number incrementor;
318 * two events or messages will never have the same sequence number unless
319 * that correspondence was made explicitly.
321 * Returns: The message's sequence number.
326 gst_message_get_seqnum (GstMessage * message)
328 g_return_val_if_fail (GST_IS_MESSAGE (message), -1);
330 return GST_MESSAGE_SEQNUM (message);
334 * gst_message_set_seqnum:
335 * @message: A #GstMessage.
336 * @seqnum: A sequence number.
338 * Set the sequence number of a message.
340 * This function might be called by the creator of a message to indicate that
341 * the message relates to other messages or events. See gst_message_get_seqnum()
342 * for more information.
347 gst_message_set_seqnum (GstMessage * message, guint32 seqnum)
349 g_return_if_fail (GST_IS_MESSAGE (message));
351 GST_MESSAGE_SEQNUM (message) = seqnum;
355 * gst_message_new_eos:
356 * @src: (transfer none): The object originating the message.
358 * Create a new eos message. This message is generated and posted in
359 * the sink elements of a GstBin. The bin will only forward the EOS
360 * message to the application if all sinks have posted an EOS message.
362 * Returns: (transfer full): The new eos message.
367 gst_message_new_eos (GstObject * src)
371 message = gst_message_new_custom (GST_MESSAGE_EOS, src, NULL);
377 * gst_message_new_error:
378 * @src: (transfer none): The object originating the message.
379 * @error: (transfer none): The GError for this message.
380 * @debug: A debugging string.
382 * Create a new error message. The message will copy @error and
383 * @debug. This message is posted by element when a fatal event
384 * occured. The pipeline will probably (partially) stop. The application
385 * receiving this message should stop the pipeline.
387 * Returns: (transfer full): the new error message.
392 gst_message_new_error (GstObject * src, GError * error, const gchar * debug)
395 GstStructure *structure;
397 structure = gst_structure_new_id (GST_QUARK (MESSAGE_ERROR),
398 GST_QUARK (GERROR), G_TYPE_ERROR, error,
399 GST_QUARK (DEBUG), G_TYPE_STRING, debug, NULL);
400 message = gst_message_new_custom (GST_MESSAGE_ERROR, src, structure);
406 * gst_message_new_warning:
407 * @src: (transfer none): The object originating the message.
408 * @error: (transfer none): The GError for this message.
409 * @debug: A debugging string.
411 * Create a new warning message. The message will make copies of @error and
414 * Returns: (transfer full): The new warning message.
419 gst_message_new_warning (GstObject * src, GError * error, const gchar * debug)
422 GstStructure *structure;
424 structure = gst_structure_new_id (GST_QUARK (MESSAGE_WARNING),
425 GST_QUARK (GERROR), G_TYPE_ERROR, error,
426 GST_QUARK (DEBUG), G_TYPE_STRING, debug, NULL);
427 message = gst_message_new_custom (GST_MESSAGE_WARNING, src, structure);
433 * gst_message_new_info:
434 * @src: (transfer none): The object originating the message.
435 * @error: (transfer none): The GError for this message.
436 * @debug: A debugging string.
438 * Create a new info message. The message will make copies of @error and
443 * Returns: (transfer full): the new info message.
446 gst_message_new_info (GstObject * src, GError * error, const gchar * debug)
449 GstStructure *structure;
451 structure = gst_structure_new_id (GST_QUARK (MESSAGE_INFO),
452 GST_QUARK (GERROR), G_TYPE_ERROR, error,
453 GST_QUARK (DEBUG), G_TYPE_STRING, debug, NULL);
454 message = gst_message_new_custom (GST_MESSAGE_INFO, src, structure);
460 * gst_message_new_tag:
461 * @src: (transfer none): The object originating the message.
462 * @tag_list: (transfer full): the tag list for the message.
464 * Create a new tag message. The message will take ownership of the tag list.
465 * The message is posted by elements that discovered a new taglist.
467 * Returns: (transfer full): the new tag message.
472 gst_message_new_tag (GstObject * src, GstTagList * tag_list)
476 GValue val = G_VALUE_INIT;
478 g_return_val_if_fail (GST_IS_TAG_LIST (tag_list), NULL);
480 s = gst_structure_new_id_empty (GST_QUARK (MESSAGE_TAG));
481 g_value_init (&val, GST_TYPE_TAG_LIST);
482 g_value_take_boxed (&val, tag_list);
483 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
484 message = gst_message_new_custom (GST_MESSAGE_TAG, src, s);
489 * gst_message_new_buffering:
490 * @src: (transfer none): The object originating the message.
491 * @percent: The buffering percent
493 * Create a new buffering message. This message can be posted by an element that
494 * needs to buffer data before it can continue processing. @percent should be a
495 * value between 0 and 100. A value of 100 means that the buffering completed.
497 * When @percent is < 100 the application should PAUSE a PLAYING pipeline. When
498 * @percent is 100, the application can set the pipeline (back) to PLAYING.
499 * The application must be prepared to receive BUFFERING messages in the
500 * PREROLLING state and may only set the pipeline to PLAYING after receiving a
501 * message with @percent set to 100, which can happen after the pipeline
502 * completed prerolling.
506 * Returns: (transfer full): The new buffering message.
509 gst_message_new_buffering (GstObject * src, gint percent)
512 GstStructure *structure;
514 g_return_val_if_fail (percent >= 0 && percent <= 100, NULL);
516 structure = gst_structure_new_id (GST_QUARK (MESSAGE_BUFFERING),
517 GST_QUARK (BUFFER_PERCENT), G_TYPE_INT, percent,
518 GST_QUARK (BUFFERING_MODE), GST_TYPE_BUFFERING_MODE, GST_BUFFERING_STREAM,
519 GST_QUARK (AVG_IN_RATE), G_TYPE_INT, -1,
520 GST_QUARK (AVG_OUT_RATE), G_TYPE_INT, -1,
521 GST_QUARK (BUFFERING_LEFT), G_TYPE_INT64, G_GINT64_CONSTANT (-1),
522 GST_QUARK (ESTIMATED_TOTAL), G_TYPE_INT64, G_GINT64_CONSTANT (-1), NULL);
523 message = gst_message_new_custom (GST_MESSAGE_BUFFERING, src, structure);
529 * gst_message_new_state_changed:
530 * @src: (transfer none): the object originating the message
531 * @oldstate: the previous state
532 * @newstate: the new (current) state
533 * @pending: the pending (target) state
535 * Create a state change message. This message is posted whenever an element
538 * Returns: (transfer full): the new state change message.
543 gst_message_new_state_changed (GstObject * src,
544 GstState oldstate, GstState newstate, GstState pending)
547 GstStructure *structure;
549 structure = gst_structure_new_id (GST_QUARK (MESSAGE_STATE_CHANGED),
550 GST_QUARK (OLD_STATE), GST_TYPE_STATE, (gint) oldstate,
551 GST_QUARK (NEW_STATE), GST_TYPE_STATE, (gint) newstate,
552 GST_QUARK (PENDING_STATE), GST_TYPE_STATE, (gint) pending, NULL);
553 message = gst_message_new_custom (GST_MESSAGE_STATE_CHANGED, src, structure);
559 * gst_message_new_state_dirty:
560 * @src: (transfer none): the object originating the message
562 * Create a state dirty message. This message is posted whenever an element
563 * changed its state asynchronously and is used internally to update the
564 * states of container objects.
566 * Returns: (transfer full): the new state dirty message.
571 gst_message_new_state_dirty (GstObject * src)
575 message = gst_message_new_custom (GST_MESSAGE_STATE_DIRTY, src, NULL);
581 * gst_message_new_clock_provide:
582 * @src: (transfer none): the object originating the message.
583 * @clock: (transfer none): the clock it provides
584 * @ready: TRUE if the sender can provide a clock
586 * Create a clock provide message. This message is posted whenever an
587 * element is ready to provide a clock or lost its ability to provide
588 * a clock (maybe because it paused or became EOS).
590 * This message is mainly used internally to manage the clock
593 * Returns: (transfer full): the new provide clock message.
598 gst_message_new_clock_provide (GstObject * src, GstClock * clock,
602 GstStructure *structure;
604 structure = gst_structure_new_id (GST_QUARK (MESSAGE_CLOCK_PROVIDE),
605 GST_QUARK (CLOCK), GST_TYPE_CLOCK, clock,
606 GST_QUARK (READY), G_TYPE_BOOLEAN, ready, NULL);
607 message = gst_message_new_custom (GST_MESSAGE_CLOCK_PROVIDE, src, structure);
613 * gst_message_new_clock_lost:
614 * @src: (transfer none): the object originating the message.
615 * @clock: (transfer none): the clock that was lost
617 * Create a clock lost message. This message is posted whenever the
618 * clock is not valid anymore.
620 * If this message is posted by the pipeline, the pipeline will
621 * select a new clock again when it goes to PLAYING. It might therefore
622 * be needed to set the pipeline to PAUSED and PLAYING again.
624 * Returns: (transfer full): The new clock lost message.
629 gst_message_new_clock_lost (GstObject * src, GstClock * clock)
632 GstStructure *structure;
634 structure = gst_structure_new_id (GST_QUARK (MESSAGE_CLOCK_LOST),
635 GST_QUARK (CLOCK), GST_TYPE_CLOCK, clock, NULL);
636 message = gst_message_new_custom (GST_MESSAGE_CLOCK_LOST, src, structure);
642 * gst_message_new_new_clock:
643 * @src: (transfer none): The object originating the message.
644 * @clock: (transfer none): the new selected clock
646 * Create a new clock message. This message is posted whenever the
647 * pipeline selectes a new clock for the pipeline.
649 * Returns: (transfer full): The new new clock message.
654 gst_message_new_new_clock (GstObject * src, GstClock * clock)
657 GstStructure *structure;
659 structure = gst_structure_new_id (GST_QUARK (MESSAGE_NEW_CLOCK),
660 GST_QUARK (CLOCK), GST_TYPE_CLOCK, clock, NULL);
661 message = gst_message_new_custom (GST_MESSAGE_NEW_CLOCK, src, structure);
667 * gst_message_new_structure_change:
668 * @src: (transfer none): The object originating the message.
669 * @type: The change type.
670 * @owner: (transfer none): The owner element of @src.
671 * @busy: Whether the structure change is busy.
673 * Create a new structure change message. This message is posted when the
674 * structure of a pipeline is in the process of being changed, for example
675 * when pads are linked or unlinked.
677 * @src should be the sinkpad that unlinked or linked.
679 * Returns: (transfer full): the new structure change message.
684 gst_message_new_structure_change (GstObject * src, GstStructureChangeType type,
685 GstElement * owner, gboolean busy)
688 GstStructure *structure;
690 g_return_val_if_fail (GST_IS_PAD (src), NULL);
691 /* g_return_val_if_fail (GST_PAD_DIRECTION (src) == GST_PAD_SINK, NULL); */
692 g_return_val_if_fail (GST_IS_ELEMENT (owner), NULL);
694 structure = gst_structure_new_id (GST_QUARK (MESSAGE_STRUCTURE_CHANGE),
695 GST_QUARK (TYPE), GST_TYPE_STRUCTURE_CHANGE_TYPE, type,
696 GST_QUARK (OWNER), GST_TYPE_ELEMENT, owner,
697 GST_QUARK (BUSY), G_TYPE_BOOLEAN, busy, NULL);
699 message = gst_message_new_custom (GST_MESSAGE_STRUCTURE_CHANGE, src,
706 * gst_message_new_segment_start:
707 * @src: (transfer none): The object originating the message.
708 * @format: The format of the position being played
709 * @position: The position of the segment being played
711 * Create a new segment message. This message is posted by elements that
712 * start playback of a segment as a result of a segment seek. This message
713 * is not received by the application but is used for maintenance reasons in
714 * container elements.
716 * Returns: (transfer full): the new segment start message.
721 gst_message_new_segment_start (GstObject * src, GstFormat format,
725 GstStructure *structure;
727 structure = gst_structure_new_id (GST_QUARK (MESSAGE_SEGMENT_START),
728 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
729 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
730 message = gst_message_new_custom (GST_MESSAGE_SEGMENT_START, src, structure);
736 * gst_message_new_segment_done:
737 * @src: (transfer none): the object originating the message.
738 * @format: The format of the position being done
739 * @position: The position of the segment being done
741 * Create a new segment done message. This message is posted by elements that
742 * finish playback of a segment as a result of a segment seek. This message
743 * is received by the application after all elements that posted a segment_start
744 * have posted the segment_done.
746 * Returns: (transfer full): the new segment done message.
751 gst_message_new_segment_done (GstObject * src, GstFormat format,
755 GstStructure *structure;
757 structure = gst_structure_new_id (GST_QUARK (MESSAGE_SEGMENT_DONE),
758 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
759 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
760 message = gst_message_new_custom (GST_MESSAGE_SEGMENT_DONE, src, structure);
766 * gst_message_new_application:
767 * @src: (transfer none): the object originating the message.
768 * @structure: (transfer full): the structure for the message. The message
769 * will take ownership of the structure.
771 * Create a new application-typed message. GStreamer will never create these
772 * messages; they are a gift from us to you. Enjoy.
774 * Returns: (transfer full): The new application message.
779 gst_message_new_application (GstObject * src, GstStructure * structure)
781 return gst_message_new_custom (GST_MESSAGE_APPLICATION, src, structure);
785 * gst_message_new_element:
786 * @src: (transfer none): The object originating the message.
787 * @structure: (transfer full): The structure for the message. The message
788 * will take ownership of the structure.
790 * Create a new element-specific message. This is meant as a generic way of
791 * allowing one-way communication from an element to an application, for example
792 * "the firewire cable was unplugged". The format of the message should be
793 * documented in the element's documentation. The structure field can be NULL.
795 * Returns: (transfer full): The new element message.
800 gst_message_new_element (GstObject * src, GstStructure * structure)
802 return gst_message_new_custom (GST_MESSAGE_ELEMENT, src, structure);
806 * gst_message_new_duration:
807 * @src: (transfer none): The object originating the message.
808 * @format: The format of the duration
809 * @duration: The new duration
811 * Create a new duration message. This message is posted by elements that
812 * know the duration of a stream in a specific format. This message
813 * is received by bins and is used to calculate the total duration of a
814 * pipeline. Elements may post a duration message with a duration of
815 * GST_CLOCK_TIME_NONE to indicate that the duration has changed and the
816 * cached duration should be discarded. The new duration can then be
817 * retrieved via a query.
819 * Returns: (transfer full): The new duration message.
824 gst_message_new_duration (GstObject * src, GstFormat format, gint64 duration)
827 GstStructure *structure;
829 structure = gst_structure_new_id (GST_QUARK (MESSAGE_DURATION),
830 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
831 GST_QUARK (DURATION), G_TYPE_INT64, duration, NULL);
832 message = gst_message_new_custom (GST_MESSAGE_DURATION, src, structure);
838 * gst_message_new_async_start:
839 * @src: (transfer none): The object originating the message.
841 * This message is posted by elements when they start an ASYNC state change.
843 * Returns: (transfer full): The new async_start message.
848 gst_message_new_async_start (GstObject * src)
852 message = gst_message_new_custom (GST_MESSAGE_ASYNC_START, src, NULL);
858 * gst_message_new_async_done:
859 * @src: (transfer none): The object originating the message.
860 * @running_time: the desired running_time
862 * The message is posted when elements completed an ASYNC state change.
863 * @running_time contains the time of the desired running_time when this
864 * elements goes to PLAYING. A value of #GST_CLOCK_TIME_NONE for @running_time
865 * means that the element has no clock interaction and thus doesn't care about
866 * the running_time of the pipeline.
868 * Returns: (transfer full): The new async_done message.
873 gst_message_new_async_done (GstObject * src, GstClockTime running_time)
876 GstStructure *structure;
878 structure = gst_structure_new_id (GST_QUARK (MESSAGE_ASYNC_DONE),
879 GST_QUARK (RUNNING_TIME), G_TYPE_UINT64, running_time, NULL);
880 message = gst_message_new_custom (GST_MESSAGE_ASYNC_DONE, src, structure);
886 * gst_message_new_latency:
887 * @src: (transfer none): The object originating the message.
889 * This message can be posted by elements when their latency requirements have
892 * Returns: (transfer full): The new latency message.
897 gst_message_new_latency (GstObject * src)
901 message = gst_message_new_custom (GST_MESSAGE_LATENCY, src, NULL);
907 * gst_message_new_request_state:
908 * @src: (transfer none): the object originating the message.
909 * @state: The new requested state
911 * This message can be posted by elements when they want to have their state
912 * changed. A typical use case would be an audio server that wants to pause the
913 * pipeline because a higher priority stream is being played.
915 * Returns: (transfer full): the new requst state message.
920 gst_message_new_request_state (GstObject * src, GstState state)
923 GstStructure *structure;
925 structure = gst_structure_new_id (GST_QUARK (MESSAGE_REQUEST_STATE),
926 GST_QUARK (NEW_STATE), GST_TYPE_STATE, (gint) state, NULL);
927 message = gst_message_new_custom (GST_MESSAGE_REQUEST_STATE, src, structure);
933 * gst_message_get_structure:
934 * @message: The #GstMessage.
936 * Access the structure of the message.
938 * Returns: (transfer none): The structure of the message. The structure is
939 * still owned by the message, which means that you should not free it and
940 * that the pointer becomes invalid when you free the message.
945 gst_message_get_structure (GstMessage * message)
947 g_return_val_if_fail (GST_IS_MESSAGE (message), NULL);
949 return GST_MESSAGE_STRUCTURE (message);
953 * gst_message_has_name:
954 * @message: The #GstMessage.
955 * @name: name to check
957 * Checks if @message has the given @name. This function is usually used to
958 * check the name of a custom message.
960 * Returns: %TRUE if @name matches the name of the message structure.
963 gst_message_has_name (GstMessage * message, const gchar * name)
965 GstStructure *structure;
967 g_return_val_if_fail (GST_IS_MESSAGE (message), FALSE);
969 structure = GST_MESSAGE_STRUCTURE (message);
970 if (structure == NULL)
973 return gst_structure_has_name (structure, name);
977 * gst_message_parse_tag:
978 * @message: A valid #GstMessage of type GST_MESSAGE_TAG.
979 * @tag_list: (out callee-allocates): return location for the tag-list.
981 * Extracts the tag list from the GstMessage. The tag list returned in the
982 * output argument is a copy; the caller must free it when done.
984 * Typical usage of this function might be:
987 * switch (GST_MESSAGE_TYPE (msg)) {
988 * case GST_MESSAGE_TAG: {
989 * GstTagList *tags = NULL;
991 * gst_message_parse_tag (msg, &tags);
992 * g_print ("Got tags from element %s\n", GST_OBJECT_NAME (msg->src));
993 * handle_tags (tags);
994 * gst_tag_list_unref (tags);
1005 gst_message_parse_tag (GstMessage * message, GstTagList ** tag_list)
1007 g_return_if_fail (GST_IS_MESSAGE (message));
1008 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_TAG);
1009 g_return_if_fail (tag_list != NULL);
1011 gst_structure_id_get (GST_MESSAGE_STRUCTURE (message),
1012 GST_QUARK (TAGLIST), GST_TYPE_TAG_LIST, tag_list, NULL);
1016 * gst_message_parse_buffering:
1017 * @message: A valid #GstMessage of type GST_MESSAGE_BUFFERING.
1018 * @percent: (out) (allow-none): Return location for the percent.
1020 * Extracts the buffering percent from the GstMessage. see also
1021 * gst_message_new_buffering().
1026 gst_message_parse_buffering (GstMessage * message, gint * percent)
1028 g_return_if_fail (GST_IS_MESSAGE (message));
1029 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_BUFFERING);
1033 g_value_get_int (gst_structure_id_get_value (GST_MESSAGE_STRUCTURE
1034 (message), GST_QUARK (BUFFER_PERCENT)));
1038 * gst_message_set_buffering_stats:
1039 * @message: A valid #GstMessage of type GST_MESSAGE_BUFFERING.
1040 * @mode: a buffering mode
1041 * @avg_in: the average input rate
1042 * @avg_out: the average output rate
1043 * @buffering_left: amount of buffering time left in milliseconds
1045 * Configures the buffering stats values in @message.
1048 gst_message_set_buffering_stats (GstMessage * message, GstBufferingMode mode,
1049 gint avg_in, gint avg_out, gint64 buffering_left)
1051 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_BUFFERING);
1053 gst_structure_id_set (GST_MESSAGE_STRUCTURE (message),
1054 GST_QUARK (BUFFERING_MODE), GST_TYPE_BUFFERING_MODE, mode,
1055 GST_QUARK (AVG_IN_RATE), G_TYPE_INT, avg_in,
1056 GST_QUARK (AVG_OUT_RATE), G_TYPE_INT, avg_out,
1057 GST_QUARK (BUFFERING_LEFT), G_TYPE_INT64, buffering_left, NULL);
1061 * gst_message_parse_buffering_stats:
1062 * @message: A valid #GstMessage of type GST_MESSAGE_BUFFERING.
1063 * @mode: (out) (allow-none): a buffering mode, or NULL
1064 * @avg_in: (out) (allow-none): the average input rate, or NULL
1065 * @avg_out: (out) (allow-none): the average output rate, or NULL
1066 * @buffering_left: (out) (allow-none): amount of buffering time left in
1067 * milliseconds, or NULL
1069 * Extracts the buffering stats values from @message.
1072 gst_message_parse_buffering_stats (GstMessage * message,
1073 GstBufferingMode * mode, gint * avg_in, gint * avg_out,
1074 gint64 * buffering_left)
1076 GstStructure *structure;
1078 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_BUFFERING);
1080 structure = GST_MESSAGE_STRUCTURE (message);
1082 *mode = (GstBufferingMode)
1083 g_value_get_enum (gst_structure_id_get_value (structure,
1084 GST_QUARK (BUFFERING_MODE)));
1086 *avg_in = g_value_get_int (gst_structure_id_get_value (structure,
1087 GST_QUARK (AVG_IN_RATE)));
1089 *avg_out = g_value_get_int (gst_structure_id_get_value (structure,
1090 GST_QUARK (AVG_OUT_RATE)));
1093 g_value_get_int64 (gst_structure_id_get_value (structure,
1094 GST_QUARK (BUFFERING_LEFT)));
1098 * gst_message_parse_state_changed:
1099 * @message: a valid #GstMessage of type GST_MESSAGE_STATE_CHANGED
1100 * @oldstate: (out) (allow-none): the previous state, or NULL
1101 * @newstate: (out) (allow-none): the new (current) state, or NULL
1102 * @pending: (out) (allow-none): the pending (target) state, or NULL
1104 * Extracts the old and new states from the GstMessage.
1106 * Typical usage of this function might be:
1109 * switch (GST_MESSAGE_TYPE (msg)) {
1110 * case GST_MESSAGE_STATE_CHANGED: {
1111 * GstState old_state, new_state;
1113 * gst_message_parse_state_changed (msg, &old_state, &new_state, NULL);
1114 * g_print ("Element %s changed state from %s to %s.\n",
1115 * GST_OBJECT_NAME (msg->src),
1116 * gst_element_state_get_name (old_state),
1117 * gst_element_state_get_name (new_state));
1128 gst_message_parse_state_changed (GstMessage * message,
1129 GstState * oldstate, GstState * newstate, GstState * pending)
1131 GstStructure *structure;
1133 g_return_if_fail (GST_IS_MESSAGE (message));
1134 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STATE_CHANGED);
1136 structure = GST_MESSAGE_STRUCTURE (message);
1138 *oldstate = (GstState)
1139 g_value_get_enum (gst_structure_id_get_value (structure,
1140 GST_QUARK (OLD_STATE)));
1142 *newstate = (GstState)
1143 g_value_get_enum (gst_structure_id_get_value (structure,
1144 GST_QUARK (NEW_STATE)));
1146 *pending = (GstState)
1147 g_value_get_enum (gst_structure_id_get_value (structure,
1148 GST_QUARK (PENDING_STATE)));
1152 * gst_message_parse_clock_provide:
1153 * @message: A valid #GstMessage of type GST_MESSAGE_CLOCK_PROVIDE.
1154 * @clock: (out) (allow-none) (transfer none): a pointer to hold a clock
1156 * @ready: (out) (allow-none): a pointer to hold the ready flag, or NULL
1158 * Extracts the clock and ready flag from the GstMessage.
1159 * The clock object returned remains valid until the message is freed.
1164 gst_message_parse_clock_provide (GstMessage * message, GstClock ** clock,
1167 const GValue *clock_gvalue;
1168 GstStructure *structure;
1170 g_return_if_fail (GST_IS_MESSAGE (message));
1171 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_CLOCK_PROVIDE);
1173 structure = GST_MESSAGE_STRUCTURE (message);
1174 clock_gvalue = gst_structure_id_get_value (structure, GST_QUARK (CLOCK));
1175 g_return_if_fail (clock_gvalue != NULL);
1176 g_return_if_fail (G_VALUE_TYPE (clock_gvalue) == GST_TYPE_CLOCK);
1180 g_value_get_boolean (gst_structure_id_get_value (structure,
1181 GST_QUARK (READY)));
1183 *clock = (GstClock *) g_value_get_object (clock_gvalue);
1187 * gst_message_parse_clock_lost:
1188 * @message: A valid #GstMessage of type GST_MESSAGE_CLOCK_LOST.
1189 * @clock: (out) (allow-none) (transfer none): a pointer to hold the lost clock
1191 * Extracts the lost clock from the GstMessage.
1192 * The clock object returned remains valid until the message is freed.
1197 gst_message_parse_clock_lost (GstMessage * message, GstClock ** clock)
1199 const GValue *clock_gvalue;
1200 GstStructure *structure;
1202 g_return_if_fail (GST_IS_MESSAGE (message));
1203 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_CLOCK_LOST);
1205 structure = GST_MESSAGE_STRUCTURE (message);
1206 clock_gvalue = gst_structure_id_get_value (structure, GST_QUARK (CLOCK));
1207 g_return_if_fail (clock_gvalue != NULL);
1208 g_return_if_fail (G_VALUE_TYPE (clock_gvalue) == GST_TYPE_CLOCK);
1211 *clock = (GstClock *) g_value_get_object (clock_gvalue);
1215 * gst_message_parse_new_clock:
1216 * @message: A valid #GstMessage of type GST_MESSAGE_NEW_CLOCK.
1217 * @clock: (out) (allow-none) (transfer none): a pointer to hold the selected
1220 * Extracts the new clock from the GstMessage.
1221 * The clock object returned remains valid until the message is freed.
1226 gst_message_parse_new_clock (GstMessage * message, GstClock ** clock)
1228 const GValue *clock_gvalue;
1229 GstStructure *structure;
1231 g_return_if_fail (GST_IS_MESSAGE (message));
1232 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_NEW_CLOCK);
1234 structure = GST_MESSAGE_STRUCTURE (message);
1235 clock_gvalue = gst_structure_id_get_value (structure, GST_QUARK (CLOCK));
1236 g_return_if_fail (clock_gvalue != NULL);
1237 g_return_if_fail (G_VALUE_TYPE (clock_gvalue) == GST_TYPE_CLOCK);
1240 *clock = (GstClock *) g_value_get_object (clock_gvalue);
1244 * gst_message_parse_structure_change:
1245 * @message: A valid #GstMessage of type GST_MESSAGE_STRUCTURE_CHANGE.
1246 * @type: (out): A pointer to hold the change type
1247 * @owner: (out) (allow-none) (transfer none): The owner element of the
1249 * @busy: (out) (allow-none): a pointer to hold whether the change is in
1250 * progress or has been completed
1252 * Extracts the change type and completion status from the GstMessage.
1257 gst_message_parse_structure_change (GstMessage * message,
1258 GstStructureChangeType * type, GstElement ** owner, gboolean * busy)
1260 const GValue *owner_gvalue;
1261 GstStructure *structure;
1263 g_return_if_fail (GST_IS_MESSAGE (message));
1264 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STRUCTURE_CHANGE);
1266 structure = GST_MESSAGE_STRUCTURE (message);
1267 owner_gvalue = gst_structure_id_get_value (structure, GST_QUARK (OWNER));
1268 g_return_if_fail (owner_gvalue != NULL);
1269 g_return_if_fail (G_VALUE_TYPE (owner_gvalue) == GST_TYPE_ELEMENT);
1272 *type = (GstStructureChangeType)
1273 g_value_get_enum (gst_structure_id_get_value (structure,
1276 *owner = (GstElement *) g_value_get_object (owner_gvalue);
1279 g_value_get_boolean (gst_structure_id_get_value (structure,
1284 * gst_message_parse_error:
1285 * @message: A valid #GstMessage of type GST_MESSAGE_ERROR.
1286 * @gerror: (out) (allow-none) (transfer full): location for the GError
1287 * @debug: (out) (allow-none) (transfer full): location for the debug message,
1290 * Extracts the GError and debug string from the GstMessage. The values returned
1291 * in the output arguments are copies; the caller must free them when done.
1293 * Typical usage of this function might be:
1296 * switch (GST_MESSAGE_TYPE (msg)) {
1297 * case GST_MESSAGE_ERROR: {
1298 * GError *err = NULL;
1299 * gchar *dbg_info = NULL;
1301 * gst_message_parse_error (msg, &err, &dbg_info);
1302 * g_printerr ("ERROR from element %s: %s\n",
1303 * GST_OBJECT_NAME (msg->src), err->message);
1304 * g_printerr ("Debugging info: %s\n", (dbg_info) ? dbg_info : "none");
1305 * g_error_free (err);
1306 * g_free (dbg_info);
1317 gst_message_parse_error (GstMessage * message, GError ** gerror, gchar ** debug)
1319 const GValue *error_gvalue;
1321 GstStructure *structure;
1323 g_return_if_fail (GST_IS_MESSAGE (message));
1324 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ERROR);
1326 structure = GST_MESSAGE_STRUCTURE (message);
1327 error_gvalue = gst_structure_id_get_value (structure, GST_QUARK (GERROR));
1328 g_return_if_fail (error_gvalue != NULL);
1329 g_return_if_fail (G_VALUE_TYPE (error_gvalue) == G_TYPE_ERROR);
1331 error_val = (GError *) g_value_get_boxed (error_gvalue);
1333 *gerror = g_error_copy (error_val);
1339 g_value_dup_string (gst_structure_id_get_value (structure,
1340 GST_QUARK (DEBUG)));
1344 * gst_message_parse_warning:
1345 * @message: A valid #GstMessage of type GST_MESSAGE_WARNING.
1346 * @gerror: (out) (allow-none) (transfer full): location for the GError
1347 * @debug: (out) (allow-none) (transfer full): location for the debug message,
1350 * Extracts the GError and debug string from the GstMessage. The values returned
1351 * in the output arguments are copies; the caller must free them when done.
1356 gst_message_parse_warning (GstMessage * message, GError ** gerror,
1359 const GValue *error_gvalue;
1361 GstStructure *structure;
1363 g_return_if_fail (GST_IS_MESSAGE (message));
1364 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_WARNING);
1366 structure = GST_MESSAGE_STRUCTURE (message);
1367 error_gvalue = gst_structure_id_get_value (structure, GST_QUARK (GERROR));
1368 g_return_if_fail (error_gvalue != NULL);
1369 g_return_if_fail (G_VALUE_TYPE (error_gvalue) == G_TYPE_ERROR);
1371 error_val = (GError *) g_value_get_boxed (error_gvalue);
1373 *gerror = g_error_copy (error_val);
1379 g_value_dup_string (gst_structure_id_get_value (structure,
1380 GST_QUARK (DEBUG)));
1384 * gst_message_parse_info:
1385 * @message: A valid #GstMessage of type GST_MESSAGE_INFO.
1386 * @gerror: (out) (allow-none) (transfer full): location for the GError
1387 * @debug: (out) (allow-none) (transfer full): location for the debug message,
1390 * Extracts the GError and debug string from the GstMessage. The values returned
1391 * in the output arguments are copies; the caller must free them when done.
1396 gst_message_parse_info (GstMessage * message, GError ** gerror, gchar ** debug)
1398 const GValue *error_gvalue;
1400 GstStructure *structure;
1402 g_return_if_fail (GST_IS_MESSAGE (message));
1403 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_INFO);
1405 structure = GST_MESSAGE_STRUCTURE (message);
1406 error_gvalue = gst_structure_id_get_value (structure, GST_QUARK (GERROR));
1407 g_return_if_fail (error_gvalue != NULL);
1408 g_return_if_fail (G_VALUE_TYPE (error_gvalue) == G_TYPE_ERROR);
1410 error_val = (GError *) g_value_get_boxed (error_gvalue);
1412 *gerror = g_error_copy (error_val);
1418 g_value_dup_string (gst_structure_id_get_value (structure,
1419 GST_QUARK (DEBUG)));
1423 * gst_message_parse_segment_start:
1424 * @message: A valid #GstMessage of type GST_MESSAGE_SEGMENT_START.
1425 * @format: (out): Result location for the format, or NULL
1426 * @position: (out): Result location for the position, or NULL
1428 * Extracts the position and format from the segment start message.
1433 gst_message_parse_segment_start (GstMessage * message, GstFormat * format,
1436 GstStructure *structure;
1438 g_return_if_fail (GST_IS_MESSAGE (message));
1439 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_SEGMENT_START);
1441 structure = GST_MESSAGE_STRUCTURE (message);
1443 *format = (GstFormat)
1444 g_value_get_enum (gst_structure_id_get_value (structure,
1445 GST_QUARK (FORMAT)));
1448 g_value_get_int64 (gst_structure_id_get_value (structure,
1449 GST_QUARK (POSITION)));
1453 * gst_message_parse_segment_done:
1454 * @message: A valid #GstMessage of type GST_MESSAGE_SEGMENT_DONE.
1455 * @format: (out): Result location for the format, or NULL
1456 * @position: (out): Result location for the position, or NULL
1458 * Extracts the position and format from the segment start message.
1463 gst_message_parse_segment_done (GstMessage * message, GstFormat * format,
1466 GstStructure *structure;
1468 g_return_if_fail (GST_IS_MESSAGE (message));
1469 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_SEGMENT_DONE);
1471 structure = GST_MESSAGE_STRUCTURE (message);
1473 *format = (GstFormat)
1474 g_value_get_enum (gst_structure_id_get_value (structure,
1475 GST_QUARK (FORMAT)));
1478 g_value_get_int64 (gst_structure_id_get_value (structure,
1479 GST_QUARK (POSITION)));
1483 * gst_message_parse_duration:
1484 * @message: A valid #GstMessage of type GST_MESSAGE_DURATION.
1485 * @format: (out): Result location for the format, or NULL
1486 * @duration: (out): Result location for the duration, or NULL
1488 * Extracts the duration and format from the duration message. The duration
1489 * might be GST_CLOCK_TIME_NONE, which indicates that the duration has
1490 * changed. Applications should always use a query to retrieve the duration
1496 gst_message_parse_duration (GstMessage * message, GstFormat * format,
1499 GstStructure *structure;
1501 g_return_if_fail (GST_IS_MESSAGE (message));
1502 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_DURATION);
1504 structure = GST_MESSAGE_STRUCTURE (message);
1506 *format = (GstFormat)
1507 g_value_get_enum (gst_structure_id_get_value (structure,
1508 GST_QUARK (FORMAT)));
1511 g_value_get_int64 (gst_structure_id_get_value (structure,
1512 GST_QUARK (DURATION)));
1516 * gst_message_parse_async_done:
1517 * @message: A valid #GstMessage of type GST_MESSAGE_ASYNC_DONE.
1518 * @running_time: (out): Result location for the running_time or NULL
1520 * Extract the running_time from the async_done message.
1525 gst_message_parse_async_done (GstMessage * message, GstClockTime * running_time)
1527 GstStructure *structure;
1529 g_return_if_fail (GST_IS_MESSAGE (message));
1530 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ASYNC_DONE);
1532 structure = GST_MESSAGE_STRUCTURE (message);
1535 g_value_get_uint64 (gst_structure_id_get_value (structure,
1536 GST_QUARK (RUNNING_TIME)));
1540 * gst_message_parse_request_state:
1541 * @message: A valid #GstMessage of type GST_MESSAGE_REQUEST_STATE.
1542 * @state: (out): Result location for the requested state or NULL
1544 * Extract the requested state from the request_state message.
1549 gst_message_parse_request_state (GstMessage * message, GstState * state)
1551 GstStructure *structure;
1553 g_return_if_fail (GST_IS_MESSAGE (message));
1554 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_REQUEST_STATE);
1556 structure = GST_MESSAGE_STRUCTURE (message);
1559 g_value_get_enum (gst_structure_id_get_value (structure,
1560 GST_QUARK (NEW_STATE)));
1564 * gst_message_new_stream_status:
1565 * @src: The object originating the message.
1566 * @type: The stream status type.
1567 * @owner: (transfer none): the owner element of @src.
1569 * Create a new stream status message. This message is posted when a streaming
1570 * thread is created/destroyed or when the state changed.
1572 * Returns: (transfer full): the new stream status message.
1577 gst_message_new_stream_status (GstObject * src, GstStreamStatusType type,
1580 GstMessage *message;
1581 GstStructure *structure;
1583 structure = gst_structure_new_id (GST_QUARK (MESSAGE_STREAM_STATUS),
1584 GST_QUARK (TYPE), GST_TYPE_STREAM_STATUS_TYPE, (gint) type,
1585 GST_QUARK (OWNER), GST_TYPE_ELEMENT, owner, NULL);
1586 message = gst_message_new_custom (GST_MESSAGE_STREAM_STATUS, src, structure);
1592 * gst_message_parse_stream_status:
1593 * @message: A valid #GstMessage of type GST_MESSAGE_STREAM_STATUS.
1594 * @type: (out): A pointer to hold the status type
1595 * @owner: (out) (transfer none): The owner element of the message source
1597 * Extracts the stream status type and owner the GstMessage. The returned
1598 * owner remains valid for as long as the reference to @message is valid and
1599 * should thus not be unreffed.
1604 gst_message_parse_stream_status (GstMessage * message,
1605 GstStreamStatusType * type, GstElement ** owner)
1607 const GValue *owner_gvalue;
1608 GstStructure *structure;
1610 g_return_if_fail (GST_IS_MESSAGE (message));
1611 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STREAM_STATUS);
1613 structure = GST_MESSAGE_STRUCTURE (message);
1614 owner_gvalue = gst_structure_id_get_value (structure, GST_QUARK (OWNER));
1615 g_return_if_fail (owner_gvalue != NULL);
1618 *type = (GstStreamStatusType)
1619 g_value_get_enum (gst_structure_id_get_value (structure,
1622 *owner = (GstElement *) g_value_get_object (owner_gvalue);
1626 * gst_message_set_stream_status_object:
1627 * @message: A valid #GstMessage of type GST_MESSAGE_STREAM_STATUS.
1628 * @object: the object controlling the streaming
1630 * Configures the object handling the streaming thread. This is usually a
1631 * GstTask object but other objects might be added in the future.
1634 gst_message_set_stream_status_object (GstMessage * message,
1635 const GValue * object)
1637 GstStructure *structure;
1639 g_return_if_fail (GST_IS_MESSAGE (message));
1640 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STREAM_STATUS);
1642 structure = GST_MESSAGE_STRUCTURE (message);
1643 gst_structure_id_set_value (structure, GST_QUARK (OBJECT), object);
1647 * gst_message_get_stream_status_object:
1648 * @message: A valid #GstMessage of type GST_MESSAGE_STREAM_STATUS.
1650 * Extracts the object managing the streaming thread from @message.
1652 * Returns: a GValue containing the object that manages the streaming thread.
1653 * This object is usually of type GstTask but other types can be added in the
1654 * future. The object remains valid as long as @message is valid.
1657 gst_message_get_stream_status_object (GstMessage * message)
1659 const GValue *result;
1660 GstStructure *structure;
1662 g_return_val_if_fail (GST_IS_MESSAGE (message), NULL);
1663 g_return_val_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STREAM_STATUS,
1666 structure = GST_MESSAGE_STRUCTURE (message);
1667 result = gst_structure_id_get_value (structure, GST_QUARK (OBJECT));
1673 * gst_message_new_step_done:
1674 * @src: The object originating the message.
1675 * @format: the format of @amount
1676 * @amount: the amount of stepped data
1677 * @rate: the rate of the stepped amount
1678 * @flush: is this an flushing step
1679 * @intermediate: is this an intermediate step
1680 * @duration: the duration of the data
1681 * @eos: the step caused EOS
1683 * This message is posted by elements when they complete a part, when @intermediate set
1684 * to TRUE, or a complete step operation.
1686 * @duration will contain the amount of time (in GST_FORMAT_TIME) of the stepped
1687 * @amount of media in format @format.
1689 * Returns: (transfer full): the new step_done message.
1694 gst_message_new_step_done (GstObject * src, GstFormat format, guint64 amount,
1695 gdouble rate, gboolean flush, gboolean intermediate, guint64 duration,
1698 GstMessage *message;
1699 GstStructure *structure;
1701 structure = gst_structure_new_id (GST_QUARK (MESSAGE_STEP_DONE),
1702 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1703 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1704 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1705 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1706 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate,
1707 GST_QUARK (DURATION), G_TYPE_UINT64, duration,
1708 GST_QUARK (EOS), G_TYPE_BOOLEAN, eos, NULL);
1709 message = gst_message_new_custom (GST_MESSAGE_STEP_DONE, src, structure);
1715 * gst_message_parse_step_done:
1716 * @message: A valid #GstMessage of type GST_MESSAGE_STEP_DONE.
1717 * @format: (out) (allow-none): result location for the format
1718 * @amount: (out) (allow-none): result location for the amount
1719 * @rate: (out) (allow-none): result location for the rate
1720 * @flush: (out) (allow-none): result location for the flush flag
1721 * @intermediate: (out) (allow-none): result location for the intermediate flag
1722 * @duration: (out) (allow-none): result location for the duration
1723 * @eos: (out) (allow-none): result location for the EOS flag
1725 * Extract the values the step_done message.
1730 gst_message_parse_step_done (GstMessage * message, GstFormat * format,
1731 guint64 * amount, gdouble * rate, gboolean * flush, gboolean * intermediate,
1732 guint64 * duration, gboolean * eos)
1734 GstStructure *structure;
1736 g_return_if_fail (GST_IS_MESSAGE (message));
1737 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STEP_DONE);
1739 structure = GST_MESSAGE_STRUCTURE (message);
1740 gst_structure_id_get (structure,
1741 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1742 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1743 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1744 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1745 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate,
1746 GST_QUARK (DURATION), G_TYPE_UINT64, duration,
1747 GST_QUARK (EOS), G_TYPE_BOOLEAN, eos, NULL);
1751 * gst_message_new_step_start:
1752 * @src: The object originating the message.
1753 * @active: if the step is active or queued
1754 * @format: the format of @amount
1755 * @amount: the amount of stepped data
1756 * @rate: the rate of the stepped amount
1757 * @flush: is this an flushing step
1758 * @intermediate: is this an intermediate step
1760 * This message is posted by elements when they accept or activate a new step
1761 * event for @amount in @format.
1763 * @active is set to FALSE when the element accepted the new step event and has
1764 * queued it for execution in the streaming threads.
1766 * @active is set to TRUE when the element has activated the step operation and
1767 * is now ready to start executing the step in the streaming thread. After this
1768 * message is emited, the application can queue a new step operation in the
1771 * Returns: (transfer full): The new step_start message.
1776 gst_message_new_step_start (GstObject * src, gboolean active, GstFormat format,
1777 guint64 amount, gdouble rate, gboolean flush, gboolean intermediate)
1779 GstMessage *message;
1780 GstStructure *structure;
1782 structure = gst_structure_new_id (GST_QUARK (MESSAGE_STEP_START),
1783 GST_QUARK (ACTIVE), G_TYPE_BOOLEAN, active,
1784 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1785 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1786 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1787 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1788 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1789 message = gst_message_new_custom (GST_MESSAGE_STEP_START, src, structure);
1795 * gst_message_parse_step_start:
1796 * @message: A valid #GstMessage of type GST_MESSAGE_STEP_DONE.
1797 * @active: (out) (allow-none): result location for the active flag
1798 * @format: (out) (allow-none): result location for the format
1799 * @amount: (out) (allow-none): result location for the amount
1800 * @rate: (out) (allow-none): result location for the rate
1801 * @flush: (out) (allow-none): result location for the flush flag
1802 * @intermediate: (out) (allow-none): result location for the intermediate flag
1804 * Extract the values from step_start message.
1809 gst_message_parse_step_start (GstMessage * message, gboolean * active,
1810 GstFormat * format, guint64 * amount, gdouble * rate, gboolean * flush,
1811 gboolean * intermediate)
1813 GstStructure *structure;
1815 g_return_if_fail (GST_IS_MESSAGE (message));
1816 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STEP_START);
1818 structure = GST_MESSAGE_STRUCTURE (message);
1819 gst_structure_id_get (structure,
1820 GST_QUARK (ACTIVE), G_TYPE_BOOLEAN, active,
1821 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1822 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1823 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1824 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1825 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1829 * gst_message_new_qos:
1830 * @src: The object originating the message.
1831 * @live: if the message was generated by a live element
1832 * @running_time: the running time of the buffer that generated the message
1833 * @stream_time: the stream time of the buffer that generated the message
1834 * @timestamp: the timestamps of the buffer that generated the message
1835 * @duration: the duration of the buffer that generated the message
1837 * A QOS message is posted on the bus whenever an element decides to drop a
1838 * buffer because of QoS reasons or whenever it changes its processing strategy
1839 * because of QoS reasons (quality adjustments such as processing at lower
1842 * This message can be posted by an element that performs synchronisation against the
1843 * clock (live) or it could be dropped by an element that performs QoS because of QOS
1844 * events received from a downstream element (!live).
1846 * @running_time, @stream_time, @timestamp, @duration should be set to the
1847 * respective running-time, stream-time, timestamp and duration of the (dropped)
1848 * buffer that generated the QoS event. Values can be left to
1849 * GST_CLOCK_TIME_NONE when unknown.
1851 * Returns: (transfer full): The new qos message.
1856 gst_message_new_qos (GstObject * src, gboolean live, guint64 running_time,
1857 guint64 stream_time, guint64 timestamp, guint64 duration)
1859 GstMessage *message;
1860 GstStructure *structure;
1862 structure = gst_structure_new_id (GST_QUARK (MESSAGE_QOS),
1863 GST_QUARK (LIVE), G_TYPE_BOOLEAN, live,
1864 GST_QUARK (RUNNING_TIME), G_TYPE_UINT64, running_time,
1865 GST_QUARK (STREAM_TIME), G_TYPE_UINT64, stream_time,
1866 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp,
1867 GST_QUARK (DURATION), G_TYPE_UINT64, duration,
1868 GST_QUARK (JITTER), G_TYPE_INT64, (gint64) 0,
1869 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, (gdouble) 1.0,
1870 GST_QUARK (QUALITY), G_TYPE_INT, (gint) 1000000,
1871 GST_QUARK (FORMAT), GST_TYPE_FORMAT, GST_FORMAT_UNDEFINED,
1872 GST_QUARK (PROCESSED), G_TYPE_UINT64, (guint64) - 1,
1873 GST_QUARK (DROPPED), G_TYPE_UINT64, (guint64) - 1, NULL);
1874 message = gst_message_new_custom (GST_MESSAGE_QOS, src, structure);
1880 * gst_message_set_qos_values:
1881 * @message: A valid #GstMessage of type GST_MESSAGE_QOS.
1882 * @jitter: The difference of the running-time against the deadline.
1883 * @proportion: Long term prediction of the ideal rate relative to normal rate
1884 * to get optimal quality.
1885 * @quality: An element dependent integer value that specifies the current
1886 * quality level of the element. The default maximum quality is 1000000.
1888 * Set the QoS values that have been calculated/analysed from the QoS data
1893 gst_message_set_qos_values (GstMessage * message, gint64 jitter,
1894 gdouble proportion, gint quality)
1896 GstStructure *structure;
1898 g_return_if_fail (GST_IS_MESSAGE (message));
1899 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_QOS);
1901 structure = GST_MESSAGE_STRUCTURE (message);
1902 gst_structure_id_set (structure,
1903 GST_QUARK (JITTER), G_TYPE_INT64, jitter,
1904 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1905 GST_QUARK (QUALITY), G_TYPE_INT, quality, NULL);
1909 * gst_message_set_qos_stats:
1910 * @message: A valid #GstMessage of type GST_MESSAGE_QOS.
1911 * @format: Units of the 'processed' and 'dropped' fields. Video sinks and video
1912 * filters will use GST_FORMAT_BUFFERS (frames). Audio sinks and audio filters
1913 * will likely use GST_FORMAT_DEFAULT (samples).
1914 * @processed: Total number of units correctly processed since the last state
1915 * change to READY or a flushing operation.
1916 * @dropped: Total number of units dropped since the last state change to READY
1917 * or a flushing operation.
1919 * Set the QoS stats representing the history of the current continuous pipeline
1922 * When @format is @GST_FORMAT_UNDEFINED both @dropped and @processed are
1923 * invalid. Values of -1 for either @processed or @dropped mean unknown values.
1928 gst_message_set_qos_stats (GstMessage * message, GstFormat format,
1929 guint64 processed, guint64 dropped)
1931 GstStructure *structure;
1933 g_return_if_fail (GST_IS_MESSAGE (message));
1934 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_QOS);
1936 structure = GST_MESSAGE_STRUCTURE (message);
1937 gst_structure_id_set (structure,
1938 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1939 GST_QUARK (PROCESSED), G_TYPE_UINT64, processed,
1940 GST_QUARK (DROPPED), G_TYPE_UINT64, dropped, NULL);
1944 * gst_message_parse_qos:
1945 * @message: A valid #GstMessage of type GST_MESSAGE_QOS.
1946 * @live: (out) (allow-none): if the message was generated by a live element
1947 * @running_time: (out) (allow-none): the running time of the buffer that
1948 * generated the message
1949 * @stream_time: (out) (allow-none): the stream time of the buffer that
1950 * generated the message
1951 * @timestamp: (out) (allow-none): the timestamps of the buffer that
1952 * generated the message
1953 * @duration: (out) (allow-none): the duration of the buffer that
1954 * generated the message
1956 * Extract the timestamps and live status from the QoS message.
1958 * The returned values give the running_time, stream_time, timestamp and
1959 * duration of the dropped buffer. Values of GST_CLOCK_TIME_NONE mean unknown
1965 gst_message_parse_qos (GstMessage * message, gboolean * live,
1966 guint64 * running_time, guint64 * stream_time, guint64 * timestamp,
1969 GstStructure *structure;
1971 g_return_if_fail (GST_IS_MESSAGE (message));
1972 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_QOS);
1974 structure = GST_MESSAGE_STRUCTURE (message);
1975 gst_structure_id_get (structure,
1976 GST_QUARK (LIVE), G_TYPE_BOOLEAN, live,
1977 GST_QUARK (RUNNING_TIME), G_TYPE_UINT64, running_time,
1978 GST_QUARK (STREAM_TIME), G_TYPE_UINT64, stream_time,
1979 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp,
1980 GST_QUARK (DURATION), G_TYPE_UINT64, duration, NULL);
1984 * gst_message_parse_qos_values:
1985 * @message: A valid #GstMessage of type GST_MESSAGE_QOS.
1986 * @jitter: (out) (allow-none): The difference of the running-time against
1988 * @proportion: (out) (allow-none): Long term prediction of the ideal rate
1989 * relative to normal rate to get optimal quality.
1990 * @quality: (out) (allow-none): An element dependent integer value that
1991 * specifies the current quality level of the element. The default
1992 * maximum quality is 1000000.
1994 * Extract the QoS values that have been calculated/analysed from the QoS data
1999 gst_message_parse_qos_values (GstMessage * message, gint64 * jitter,
2000 gdouble * proportion, gint * quality)
2002 GstStructure *structure;
2004 g_return_if_fail (GST_IS_MESSAGE (message));
2005 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_QOS);
2007 structure = GST_MESSAGE_STRUCTURE (message);
2008 gst_structure_id_get (structure,
2009 GST_QUARK (JITTER), G_TYPE_INT64, jitter,
2010 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
2011 GST_QUARK (QUALITY), G_TYPE_INT, quality, NULL);
2015 * gst_message_parse_qos_stats:
2016 * @message: A valid #GstMessage of type GST_MESSAGE_QOS.
2017 * @format: (out) (allow-none): Units of the 'processed' and 'dropped' fields.
2018 * Video sinks and video filters will use GST_FORMAT_BUFFERS (frames).
2019 * Audio sinks and audio filters will likely use GST_FORMAT_DEFAULT
2021 * @processed: (out) (allow-none): Total number of units correctly processed
2022 * since the last state change to READY or a flushing operation.
2023 * @dropped: (out) (allow-none): Total number of units dropped since the last
2024 * state change to READY or a flushing operation.
2026 * Extract the QoS stats representing the history of the current continuous
2027 * pipeline playback period.
2029 * When @format is @GST_FORMAT_UNDEFINED both @dropped and @processed are
2030 * invalid. Values of -1 for either @processed or @dropped mean unknown values.
2035 gst_message_parse_qos_stats (GstMessage * message, GstFormat * format,
2036 guint64 * processed, guint64 * dropped)
2038 GstStructure *structure;
2040 g_return_if_fail (GST_IS_MESSAGE (message));
2041 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_QOS);
2043 structure = GST_MESSAGE_STRUCTURE (message);
2044 gst_structure_id_get (structure,
2045 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
2046 GST_QUARK (PROCESSED), G_TYPE_UINT64, processed,
2047 GST_QUARK (DROPPED), G_TYPE_UINT64, dropped, NULL);
2051 * gst_message_new_progress:
2052 * @src: The object originating the message.
2053 * @type: a #GstProgressType
2054 * @code: a progress code
2055 * @text: free, user visible text describing the progress
2057 * Progress messages are posted by elements when they use an asynchronous task
2058 * to perform actions triggered by a state change.
2060 * @code contains a well defined string describing the action.
2061 * @test should contain a user visible string detailing the current action.
2063 * Returns: (transfer full): The new qos message.
2066 gst_message_new_progress (GstObject * src, GstProgressType type,
2067 const gchar * code, const gchar * text)
2069 GstMessage *message;
2070 GstStructure *structure;
2071 gint percent = 100, timeout = -1;
2073 g_return_val_if_fail (code != NULL, NULL);
2074 g_return_val_if_fail (text != NULL, NULL);
2076 if (type == GST_PROGRESS_TYPE_START || type == GST_PROGRESS_TYPE_CONTINUE)
2079 structure = gst_structure_new_id (GST_QUARK (MESSAGE_PROGRESS),
2080 GST_QUARK (TYPE), GST_TYPE_PROGRESS_TYPE, type,
2081 GST_QUARK (CODE), G_TYPE_STRING, code,
2082 GST_QUARK (TEXT), G_TYPE_STRING, text,
2083 GST_QUARK (PERCENT), G_TYPE_INT, percent,
2084 GST_QUARK (TIMEOUT), G_TYPE_INT, timeout, NULL);
2085 message = gst_message_new_custom (GST_MESSAGE_PROGRESS, src, structure);
2091 * gst_message_parse_progress:
2092 * @message: A valid #GstMessage of type GST_MESSAGE_PROGRESS.
2093 * @type: (out) (allow-none): location for the type
2094 * @code: (out) (allow-none) (transfer full): location for the code
2095 * @text: (out) (allow-none) (transfer full): location for the text
2097 * Parses the progress @type, @code and @text.
2100 gst_message_parse_progress (GstMessage * message, GstProgressType * type,
2101 gchar ** code, gchar ** text)
2103 GstStructure *structure;
2105 g_return_if_fail (GST_IS_MESSAGE (message));
2106 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_PROGRESS);
2108 structure = GST_MESSAGE_STRUCTURE (message);
2109 gst_structure_id_get (structure,
2110 GST_QUARK (TYPE), GST_TYPE_PROGRESS_TYPE, type,
2111 GST_QUARK (CODE), G_TYPE_STRING, code,
2112 GST_QUARK (TEXT), G_TYPE_STRING, text, NULL);
2116 * gst_message_new_toc:
2117 * @src: the object originating the message.
2118 * @toc: (transfer none): #GstToc structure for the message.
2119 * @updated: whether TOC was updated or not.
2121 * Create a new TOC message. The message is posted by elements
2122 * that discovered or updated a TOC.
2124 * Returns: (transfer full): a new TOC message.
2129 gst_message_new_toc (GstObject * src, GstToc * toc, gboolean updated)
2131 GstStructure *toc_struct;
2133 g_return_val_if_fail (toc != NULL, NULL);
2135 toc_struct = gst_structure_new_id (GST_QUARK (MESSAGE_TOC),
2136 GST_QUARK (TOC), GST_TYPE_TOC, toc,
2137 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
2139 return gst_message_new_custom (GST_MESSAGE_TOC, src, toc_struct);
2143 * gst_message_parse_toc:
2144 * @message: a valid #GstMessage of type GST_MESSAGE_TOC.
2145 * @toc: (out) (transfer full): return location for the TOC.
2146 * @updated: (out): return location for the updated flag.
2148 * Extract thef TOC from the #GstMessage. The TOC returned in the
2149 * output argument is a copy; the caller must free it with
2150 * gst_toc_unref() when done.
2155 gst_message_parse_toc (GstMessage * message, GstToc ** toc, gboolean * updated)
2157 g_return_if_fail (GST_IS_MESSAGE (message));
2158 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_TOC);
2159 g_return_if_fail (toc != NULL);
2161 gst_structure_id_get (GST_MESSAGE_STRUCTURE (message),
2162 GST_QUARK (TOC), GST_TYPE_TOC, toc,
2163 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
2167 * gst_message_new_reset_time:
2168 * @src: (transfer none): The object originating the message.
2169 * @running_time: the requested running-time
2171 * This message is posted when the pipeline running-time should be reset to
2172 * @running_time, like after a flushing seek.
2174 * Returns: (transfer full): The new reset_time message.
2179 gst_message_new_reset_time (GstObject * src, GstClockTime running_time)
2181 GstMessage *message;
2182 GstStructure *structure;
2184 structure = gst_structure_new_id (GST_QUARK (MESSAGE_RESET_TIME),
2185 GST_QUARK (RUNNING_TIME), G_TYPE_UINT64, running_time, NULL);
2186 message = gst_message_new_custom (GST_MESSAGE_RESET_TIME, src, structure);
2192 * gst_message_parse_reset_time:
2193 * @message: A valid #GstMessage of type GST_MESSAGE_RESET_TIME.
2194 * @running_time: (out): Result location for the running_time or NULL
2196 * Extract the running-time from the RESET_TIME message.
2201 gst_message_parse_reset_time (GstMessage * message, GstClockTime * running_time)
2203 GstStructure *structure;
2205 g_return_if_fail (GST_IS_MESSAGE (message));
2206 g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_RESET_TIME);
2208 structure = GST_MESSAGE_STRUCTURE (message);
2211 g_value_get_uint64 (gst_structure_id_get_value (structure,
2212 GST_QUARK (RUNNING_TIME)));
2216 * gst_message_new_stream_start:
2217 * @src: (transfer none): The object originating the message.
2219 * Create a new stream_start message. This message is generated and posted in
2220 * the sink elements of a GstBin. The bin will only forward the STREAM_START
2221 * message to the application if all sinks have posted an STREAM_START message.
2223 * Returns: (transfer full): The new stream_start message.
2228 gst_message_new_stream_start (GstObject * src)
2230 GstMessage *message;
2232 message = gst_message_new_custom (GST_MESSAGE_STREAM_START, src, NULL);