2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wim.taymans@chello.be>
4 * 2005 Wim Taymans <wim@fluendo.com>
6 * gstevent.c: GstEvent subsystem
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
26 * @short_description: Structure describing events that are passed up and down
28 * @see_also: #GstPad, #GstElement
30 * The event class provides factory methods to construct events for sending
31 * and functions to query (parse) received events.
33 * Events are usually created with gst_event_new_*() which takes event-type
34 * specific parameters as arguments.
35 * To send an event application will usually use gst_element_send_event() and
36 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 * The event should be unreffed with gst_event_unref() if it has not been sent.
39 * Events that have been received can be parsed with their respective
40 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
42 * Events are passed between elements in parallel to the data stream. Some events
43 * are serialized with buffers, others are not. Some events only travel downstream,
44 * others only upstream. Some events can travel both upstream and downstream.
46 * The events are used to signal special conditions in the datastream such as
47 * EOS (end of stream) or the start of a new stream-segment.
48 * Events are also used to flush the pipeline of any pending data.
50 * Most of the event API is used inside plugins. Applications usually only
51 * construct and use seek events.
52 * To do that gst_event_new_seek() is used to create a seek event. It takes
53 * the needed parameters to specify seeking time and mode.
55 * <title>performing a seek on a pipeline</title>
60 * // construct a seek event to play the media from second 2 to 5, flush
61 * // the pipeline to decrease latency.
62 * event = gst_event_new_seek (1.0,
64 * GST_SEEK_FLAG_FLUSH,
65 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
66 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
68 * result = gst_element_send_event (pipeline, event);
70 * g_warning ("seek failed");
75 * Last reviewed on 2012-03-28 (0.11.3)
79 #include "gst_private.h"
80 #include <string.h> /* memcpy */
84 #include "gstenumtypes.h"
89 GType _gst_event_type = 0;
95 GstStructure *structure;
98 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
107 static GstEventQuarks event_quarks[] = {
108 {GST_EVENT_UNKNOWN, "unknown", 0},
109 {GST_EVENT_FLUSH_START, "flush-start", 0},
110 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
111 {GST_EVENT_STREAM_START, "stream-start", 0},
112 {GST_EVENT_CAPS, "caps", 0},
113 {GST_EVENT_SEGMENT, "segment", 0},
114 {GST_EVENT_TAG, "tag", 0},
115 {GST_EVENT_TOC, "toc", 0},
116 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
117 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
118 {GST_EVENT_EOS, "eos", 0},
119 {GST_EVENT_CONTEXT, "context", 0},
120 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
121 {GST_EVENT_GAP, "gap", 0},
122 {GST_EVENT_QOS, "qos", 0},
123 {GST_EVENT_SEEK, "seek", 0},
124 {GST_EVENT_NAVIGATION, "navigation", 0},
125 {GST_EVENT_LATENCY, "latency", 0},
126 {GST_EVENT_STEP, "step", 0},
127 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
128 {GST_EVENT_TOC_SELECT, "toc-select", 0},
129 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
130 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
131 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
132 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
133 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
134 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
139 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
142 _priv_gst_event_initialize (void)
146 _gst_event_type = gst_event_get_type ();
148 g_type_class_ref (gst_seek_flags_get_type ());
149 g_type_class_ref (gst_seek_type_get_type ());
151 for (i = 0; event_quarks[i].name; i++) {
152 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
157 * gst_event_type_get_name:
158 * @type: the event type
160 * Get a printable name for the given event type. Do not modify or free.
162 * Returns: a reference to the static name of the event.
165 gst_event_type_get_name (GstEventType type)
169 for (i = 0; event_quarks[i].name; i++) {
170 if (type == event_quarks[i].type)
171 return event_quarks[i].name;
177 * gst_event_type_to_quark:
178 * @type: the event type
180 * Get the unique quark for the given event type.
182 * Returns: the quark associated with the event type
185 gst_event_type_to_quark (GstEventType type)
189 for (i = 0; event_quarks[i].name; i++) {
190 if (type == event_quarks[i].type)
191 return event_quarks[i].quark;
197 * gst_event_type_get_flags:
198 * @type: a #GstEventType
200 * Gets the #GstEventTypeFlags associated with @type.
202 * Returns: a #GstEventTypeFlags.
205 gst_event_type_get_flags (GstEventType type)
207 GstEventTypeFlags ret;
209 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
215 _gst_event_free (GstEvent * event)
219 g_return_if_fail (event != NULL);
220 g_return_if_fail (GST_IS_EVENT (event));
222 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
223 GST_EVENT_TYPE_NAME (event));
225 s = GST_EVENT_STRUCTURE (event);
228 gst_structure_set_parent_refcount (s, NULL);
229 gst_structure_free (s);
232 g_slice_free1 (sizeof (GstEventImpl), event);
235 static void gst_event_init (GstEventImpl * event, GstEventType type);
238 _gst_event_copy (GstEvent * event)
243 copy = g_slice_new0 (GstEventImpl);
245 gst_event_init (copy, GST_EVENT_TYPE (event));
247 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
248 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
250 s = GST_EVENT_STRUCTURE (event);
252 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
253 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
254 ©->event.mini_object.refcount);
256 GST_EVENT_STRUCTURE (copy) = NULL;
258 return GST_EVENT_CAST (copy);
262 gst_event_init (GstEventImpl * event, GstEventType type)
264 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
265 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
266 (GstMiniObjectFreeFunction) _gst_event_free);
268 GST_EVENT_TYPE (event) = type;
269 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
270 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
275 * gst_event_new_custom:
276 * @type: The type of the new event
277 * @structure: (transfer full): the structure for the event. The event will
278 * take ownership of the structure.
280 * Create a new custom-typed event. This can be used for anything not
281 * handled by other event-specific functions to pass an event to another
284 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
285 * assigning a free number and filling in the correct direction and
286 * serialization flags.
288 * New custom events can also be created by subclassing the event type if
291 * Returns: (transfer full): the new custom event.
294 gst_event_new_custom (GstEventType type, GstStructure * structure)
298 event = g_slice_new0 (GstEventImpl);
300 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
301 gst_event_type_get_name (type), type);
304 /* structure must not have a parent */
305 if (!gst_structure_set_parent_refcount (structure,
306 &event->event.mini_object.refcount))
310 gst_event_init (event, type);
312 GST_EVENT_STRUCTURE (event) = structure;
314 return GST_EVENT_CAST (event);
319 g_slice_free1 (sizeof (GstEventImpl), event);
320 g_warning ("structure is already owned by another object");
326 * gst_event_get_structure:
327 * @event: The #GstEvent.
329 * Access the structure of the event.
331 * Returns: The structure of the event. The structure is still
332 * owned by the event, which means that you should not free it and
333 * that the pointer becomes invalid when you free the event.
338 gst_event_get_structure (GstEvent * event)
340 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
342 return GST_EVENT_STRUCTURE (event);
346 * gst_event_writable_structure:
347 * @event: The #GstEvent.
349 * Get a writable version of the structure.
351 * Returns: The structure of the event. The structure is still
352 * owned by the event, which means that you should not free it and
353 * that the pointer becomes invalid when you free the event.
354 * This function checks if @event is writable and will never return NULL.
359 gst_event_writable_structure (GstEvent * event)
361 GstStructure *structure;
363 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
364 g_return_val_if_fail (gst_event_is_writable (event), NULL);
366 structure = GST_EVENT_STRUCTURE (event);
368 if (structure == NULL) {
370 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
372 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
373 GST_EVENT_STRUCTURE (event) = structure;
379 * gst_event_has_name:
380 * @event: The #GstEvent.
381 * @name: name to check
383 * Checks if @event has the given @name. This function is usually used to
384 * check the name of a custom event.
386 * Returns: %TRUE if @name matches the name of the event structure.
389 gst_event_has_name (GstEvent * event, const gchar * name)
391 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
393 if (GST_EVENT_STRUCTURE (event) == NULL)
396 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
400 * gst_event_get_seqnum:
401 * @event: A #GstEvent.
403 * Retrieve the sequence number of a event.
405 * Events have ever-incrementing sequence numbers, which may also be set
406 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
407 * indicate that a event corresponds to some other set of events or messages,
408 * for example an EOS event corresponding to a SEEK event. It is considered good
409 * practice to make this correspondence when possible, though it is not
412 * Note that events and messages share the same sequence number incrementor;
413 * two events or messages will never have the same sequence number unless
414 * that correspondence was made explicitly.
416 * Returns: The event's sequence number.
421 gst_event_get_seqnum (GstEvent * event)
423 g_return_val_if_fail (GST_IS_EVENT (event), -1);
425 return GST_EVENT_SEQNUM (event);
429 * gst_event_set_seqnum:
430 * @event: A #GstEvent.
431 * @seqnum: A sequence number.
433 * Set the sequence number of a event.
435 * This function might be called by the creator of a event to indicate that the
436 * event relates to other events or messages. See gst_event_get_seqnum() for
442 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
444 g_return_if_fail (GST_IS_EVENT (event));
446 GST_EVENT_SEQNUM (event) = seqnum;
450 * gst_event_new_flush_start:
452 * Allocate a new flush start event. The flush start event can be sent
453 * upstream and downstream and travels out-of-bounds with the dataflow.
455 * It marks pads as being flushing and will make them return
456 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
457 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
458 * Any event (except a #GST_EVENT_FLUSH_STOP) received
459 * on a flushing pad will return %FALSE immediately.
461 * Elements should unlock any blocking functions and exit their streaming
462 * functions as fast as possible when this event is received.
464 * This event is typically generated after a seek to flush out all queued data
465 * in the pipeline so that the new media is played as soon as possible.
467 * Returns: (transfer full): a new flush start event.
470 gst_event_new_flush_start (void)
472 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
476 * gst_event_new_flush_stop:
477 * @reset_time: if time should be reset
479 * Allocate a new flush stop event. The flush stop event can be sent
480 * upstream and downstream and travels serialized with the dataflow.
481 * It is typically sent after sending a FLUSH_START event to make the
482 * pads accept data again.
484 * Elements can process this event synchronized with the dataflow since
485 * the preceeding FLUSH_START event stopped the dataflow.
487 * This event is typically generated to complete a seek and to resume
490 * Returns: (transfer full): a new flush stop event.
493 gst_event_new_flush_stop (gboolean reset_time)
497 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
499 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
500 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
501 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
507 * gst_event_parse_flush_stop:
508 * @event: The event to parse
509 * @reset_time: (out): if time should be reset
511 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
514 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
516 GstStructure *structure;
518 g_return_if_fail (GST_IS_EVENT (event));
519 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
521 structure = GST_EVENT_STRUCTURE (event);
522 if (G_LIKELY (reset_time))
524 g_value_get_boolean (gst_structure_id_get_value (structure,
525 GST_QUARK (RESET_TIME)));
531 * Create a new EOS event. The eos event can only travel downstream
532 * synchronized with the buffer flow. Elements that receive the EOS
533 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
534 * when data after the EOS event arrives.
536 * The EOS event will travel down to the sink elements in the pipeline
537 * which will then post the #GST_MESSAGE_EOS on the bus after they have
538 * finished playing any buffered data.
540 * When all sinks have posted an EOS message, an EOS message is
541 * forwarded to the application.
543 * The EOS event itself will not cause any state transitions of the pipeline.
545 * Returns: (transfer full): the new EOS event.
548 gst_event_new_eos (void)
550 return gst_event_new_custom (GST_EVENT_EOS, NULL);
555 * @timestamp: the start time (pts) of the gap
556 * @duration: the duration of the gap
558 * Create a new GAP event. A gap event can be thought of as conceptually
559 * equivalent to a buffer to signal that there is no data for a certain
560 * amount of time. This is useful to signal a gap to downstream elements
561 * which may wait for data, such as muxers or mixers or overlays, especially
562 * for sparse streams such as subtitle streams.
564 * Returns: (transfer full): the new GAP event.
567 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
571 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
573 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
574 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
575 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
576 GST_TIME_ARGS (duration));
578 event = gst_event_new_custom (GST_EVENT_GAP,
579 gst_structure_new_id (GST_QUARK (EVENT_GAP),
580 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
581 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
587 * gst_event_parse_gap:
588 * @event: a #GstEvent of type #GST_EVENT_GAP
589 * @timestamp: (out) (allow-none): location where to store the
590 * start time (pts) of the gap, or %NULL
591 * @duration: (out) (allow-none): location where to store the duration of
594 * Extract timestamp and duration from a new GAP event.
597 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
598 GstClockTime * duration)
600 GstStructure *structure;
602 g_return_if_fail (GST_IS_EVENT (event));
603 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
605 structure = GST_EVENT_STRUCTURE (event);
606 gst_structure_id_get (structure,
607 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
608 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
612 * gst_event_new_caps:
613 * @caps: (transfer none): a #GstCaps
615 * Create a new CAPS event for @caps. The caps event can only travel downstream
616 * synchronized with the buffer flow and contains the format of the buffers
617 * that will follow after the event.
619 * Returns: (transfer full): the new CAPS event.
622 gst_event_new_caps (GstCaps * caps)
626 g_return_val_if_fail (caps != NULL, NULL);
627 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
629 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
631 event = gst_event_new_custom (GST_EVENT_CAPS,
632 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
633 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
639 * gst_event_parse_caps:
640 * @event: The event to parse
641 * @caps: (out) (transfer none): A pointer to the caps
643 * Get the caps from @event. The caps remains valid as long as @event remains
647 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
649 GstStructure *structure;
651 g_return_if_fail (GST_IS_EVENT (event));
652 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
654 structure = GST_EVENT_STRUCTURE (event);
657 g_value_get_boxed (gst_structure_id_get_value (structure,
662 * gst_event_new_segment:
663 * @segment: (transfer none): a #GstSegment
665 * Create a new SEGMENT event for @segment. The segment event can only travel
666 * downstream synchronized with the buffer flow and contains timing information
667 * and playback properties for the buffers that will follow.
669 * The newsegment event marks the range of buffers to be processed. All
670 * data not within the segment range is not to be processed. This can be
671 * used intelligently by plugins to apply more efficient methods of skipping
672 * unneeded data. The valid range is expressed with the @start and @stop
675 * The time value of the segment is used in conjunction with the start
676 * value to convert the buffer timestamps into the stream time. This is
677 * usually done in sinks to report the current stream_time.
678 * @time represents the stream_time of a buffer carrying a timestamp of
679 * @start. @time cannot be -1.
681 * @start cannot be -1, @stop can be -1. If there
682 * is a valid @stop given, it must be greater or equal the @start, including
683 * when the indicated playback @rate is < 0.
685 * The @applied_rate value provides information about any rate adjustment that
686 * has already been made to the timestamps and content on the buffers of the
687 * stream. (@rate * @applied_rate) should always equal the rate that has been
688 * requested for playback. For example, if an element has an input segment
689 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
690 * incoming timestamps and buffer content by half and output a newsegment event
691 * with @rate of 1.0 and @applied_rate of 2.0
693 * After a newsegment event, the buffer stream time is calculated with:
695 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
697 * Returns: (transfer full): the new SEGMENT event.
700 gst_event_new_segment (const GstSegment * segment)
704 g_return_val_if_fail (segment != NULL, NULL);
705 g_return_val_if_fail (segment->rate != 0.0, NULL);
706 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
707 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
709 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
712 event = gst_event_new_custom (GST_EVENT_SEGMENT,
713 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
714 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
720 * gst_event_parse_segment:
721 * @event: The event to parse
722 * @segment: (out) (transfer none): a pointer to a #GstSegment
724 * Parses a segment @event and stores the result in the given @segment location.
725 * @segment remains valid only until the @event is freed. Don't modify the segment
726 * and make a copy if you want to modify it or store it for later use.
729 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
731 GstStructure *structure;
733 g_return_if_fail (GST_IS_EVENT (event));
734 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
737 structure = GST_EVENT_STRUCTURE (event);
738 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
739 GST_QUARK (SEGMENT)));
744 * gst_event_copy_segment:
745 * @event: The event to parse
746 * @segment: a pointer to a #GstSegment
748 * Parses a segment @event and copies the #GstSegment into the location
752 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
754 const GstSegment *src;
756 g_return_if_fail (GST_IS_EVENT (event));
757 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
760 gst_event_parse_segment (event, &src);
761 gst_segment_copy_into (src, segment);
767 * @taglist: (transfer full): metadata list. The event will take ownership
770 * Generates a metadata tag event from the given @taglist.
772 * The scope of the taglist specifies if the taglist applies to the
773 * complete medium or only to this specific stream. As the tag event
774 * is a sticky event, elements should merge tags received from
775 * upstream with a given scope with their own tags with the same
776 * scope and create a new tag event from it.
778 * Returns: (transfer full): a new #GstEvent
781 gst_event_new_tag (GstTagList * taglist)
784 GValue val = G_VALUE_INIT;
785 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
787 g_return_val_if_fail (taglist != NULL, NULL);
789 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
790 g_value_init (&val, GST_TYPE_TAG_LIST);
791 g_value_take_boxed (&val, taglist);
792 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
793 return gst_event_new_custom (GST_EVENT_TAG, s);
797 * gst_event_parse_tag:
798 * @event: a tag event
799 * @taglist: (out) (transfer none): pointer to metadata list
801 * Parses a tag @event and stores the results in the given @taglist location.
802 * No reference to the taglist will be returned, it remains valid only until
803 * the @event is freed. Don't modify or free the taglist, make a copy if you
804 * want to modify it or store it for later use.
807 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
811 g_return_if_fail (GST_IS_EVENT (event));
812 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
814 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
815 GST_QUARK (TAGLIST));
818 *taglist = (GstTagList *) g_value_get_boxed (val);
821 /* buffersize event */
823 * gst_event_new_buffer_size:
824 * @format: buffer format
825 * @minsize: minimum buffer size
826 * @maxsize: maximum buffer size
827 * @async: thread behavior
829 * Create a new buffersize event. The event is sent downstream and notifies
830 * elements that they should provide a buffer of the specified dimensions.
832 * When the @async flag is set, a thread boundary is preferred.
834 * Returns: (transfer full): a new #GstEvent
837 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
838 gint64 maxsize, gboolean async)
841 GstStructure *structure;
843 GST_CAT_INFO (GST_CAT_EVENT,
844 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
845 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
846 minsize, maxsize, async);
848 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
849 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
850 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
851 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
852 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
853 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
859 * gst_event_parse_buffer_size:
860 * @event: The event to query
861 * @format: (out): A pointer to store the format in
862 * @minsize: (out): A pointer to store the minsize in
863 * @maxsize: (out): A pointer to store the maxsize in
864 * @async: (out): A pointer to store the async-flag in
866 * Get the format, minsize, maxsize and async-flag in the buffersize event.
869 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
870 gint64 * minsize, gint64 * maxsize, gboolean * async)
872 const GstStructure *structure;
874 g_return_if_fail (GST_IS_EVENT (event));
875 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
877 structure = GST_EVENT_STRUCTURE (event);
879 *format = (GstFormat)
880 g_value_get_enum (gst_structure_id_get_value (structure,
881 GST_QUARK (FORMAT)));
884 g_value_get_int64 (gst_structure_id_get_value (structure,
885 GST_QUARK (MINSIZE)));
888 g_value_get_int64 (gst_structure_id_get_value (structure,
889 GST_QUARK (MAXSIZE)));
892 g_value_get_boolean (gst_structure_id_get_value (structure,
898 * @type: the QoS type
899 * @proportion: the proportion of the qos message
900 * @diff: The time difference of the last Clock sync
901 * @timestamp: The timestamp of the buffer
903 * Allocate a new qos event with the given values.
904 * The QOS event is generated in an element that wants an upstream
905 * element to either reduce or increase its rate because of
906 * high/low CPU load or other resource usage such as network performance or
907 * throttling. Typically sinks generate these events for each buffer
910 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
911 * used when a buffer arrived in time or when the sink cannot keep up with
912 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
913 * receiving buffers fast enough and thus has to drop late buffers.
914 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
915 * by the application, for example to reduce power consumption.
917 * @proportion indicates the real-time performance of the streaming in the
918 * element that generated the QoS event (usually the sink). The value is
919 * generally computed based on more long term statistics about the streams
920 * timestamps compared to the clock.
921 * A value < 1.0 indicates that the upstream element is producing data faster
922 * than real-time. A value > 1.0 indicates that the upstream element is not
923 * producing data fast enough. 1.0 is the ideal @proportion value. The
924 * proportion value can safely be used to lower or increase the quality of
927 * @diff is the difference against the clock in running time of the last
928 * buffer that caused the element to generate the QOS event. A negative value
929 * means that the buffer with @timestamp arrived in time. A positive value
930 * indicates how late the buffer with @timestamp was. When throttling is
931 * enabled, @diff will be set to the requested throttling interval.
933 * @timestamp is the timestamp of the last buffer that cause the element
934 * to generate the QOS event. It is expressed in running time and thus an ever
937 * The upstream element can use the @diff and @timestamp values to decide
938 * whether to process more buffers. For possitive @diff, all buffers with
939 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
940 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
941 * result smaller than 0 is not allowed.
943 * The application can use general event probes to intercept the QoS
944 * event and implement custom application specific QoS handling.
946 * Returns: (transfer full): a new QOS event.
949 gst_event_new_qos (GstQOSType type, gdouble proportion,
950 GstClockTimeDiff diff, GstClockTime timestamp)
953 GstStructure *structure;
955 /* diff must be positive or timestamp + diff must be positive */
956 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
958 GST_CAT_LOG (GST_CAT_EVENT,
959 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
960 ", timestamp %" GST_TIME_FORMAT, type, proportion,
961 diff, GST_TIME_ARGS (timestamp));
963 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
964 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
965 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
966 GST_QUARK (DIFF), G_TYPE_INT64, diff,
967 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
968 event = gst_event_new_custom (GST_EVENT_QOS, structure);
974 * gst_event_parse_qos:
975 * @event: The event to query
976 * @type: (out): A pointer to store the QoS type in
977 * @proportion: (out): A pointer to store the proportion in
978 * @diff: (out): A pointer to store the diff in
979 * @timestamp: (out): A pointer to store the timestamp in
981 * Get the type, proportion, diff and timestamp in the qos event. See
982 * gst_event_new_qos() for more information about the different QoS values.
985 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
986 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
988 const GstStructure *structure;
990 g_return_if_fail (GST_IS_EVENT (event));
991 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
993 structure = GST_EVENT_STRUCTURE (event);
996 g_value_get_enum (gst_structure_id_get_value (structure,
1000 g_value_get_double (gst_structure_id_get_value (structure,
1001 GST_QUARK (PROPORTION)));
1004 g_value_get_int64 (gst_structure_id_get_value (structure,
1008 g_value_get_uint64 (gst_structure_id_get_value (structure,
1009 GST_QUARK (TIMESTAMP)));
1013 * gst_event_new_seek:
1014 * @rate: The new playback rate
1015 * @format: The format of the seek values
1016 * @flags: The optional seek flags
1017 * @start_type: The type and flags for the new start position
1018 * @start: The value of the new start position
1019 * @stop_type: The type and flags for the new stop position
1020 * @stop: The value of the new stop position
1022 * Allocate a new seek event with the given parameters.
1024 * The seek event configures playback of the pipeline between @start to @stop
1025 * at the speed given in @rate, also called a playback segment.
1026 * The @start and @stop values are expressed in @format.
1028 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1029 * Negatives values means backwards playback. A value of 0.0 for the
1030 * rate is not allowed and should be accomplished instead by PAUSING the
1033 * A pipeline has a default playback segment configured with a start
1034 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1035 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1037 * @start_type and @stop_type specify how to adjust the currently configured
1038 * start and stop fields in playback segment. Adjustments can be made relative
1039 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1040 * means that the position should not be updated.
1042 * When the rate is positive and @start has been updated, playback will start
1043 * from the newly configured start position.
1045 * For negative rates, playback will start from the newly configured stop
1046 * position (if any). If the stop position is updated, it must be different from
1047 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1049 * It is not possible to seek relative to the current playback position, to do
1050 * this, PAUSE the pipeline, query the current playback position with
1051 * #GST_QUERY_POSITION and update the playback segment current position with a
1052 * #GST_SEEK_TYPE_SET to the desired position.
1054 * Returns: (transfer full): a new seek event.
1057 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1058 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1061 GstStructure *structure;
1063 g_return_val_if_fail (rate != 0.0, NULL);
1065 if (format == GST_FORMAT_TIME) {
1066 GST_CAT_INFO (GST_CAT_EVENT,
1067 "creating seek rate %lf, format TIME, flags %d, "
1068 "start_type %d, start %" GST_TIME_FORMAT ", "
1069 "stop_type %d, stop %" GST_TIME_FORMAT,
1070 rate, flags, start_type, GST_TIME_ARGS (start),
1071 stop_type, GST_TIME_ARGS (stop));
1073 GST_CAT_INFO (GST_CAT_EVENT,
1074 "creating seek rate %lf, format %s, flags %d, "
1075 "start_type %d, start %" G_GINT64_FORMAT ", "
1076 "stop_type %d, stop %" G_GINT64_FORMAT,
1077 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1081 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1082 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1083 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1084 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1085 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1086 GST_QUARK (CUR), G_TYPE_INT64, start,
1087 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1088 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1089 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1095 * gst_event_parse_seek:
1096 * @event: a seek event
1097 * @rate: (out): result location for the rate
1098 * @format: (out): result location for the stream format
1099 * @flags: (out): result location for the #GstSeekFlags
1100 * @start_type: (out): result location for the #GstSeekType of the start position
1101 * @start: (out): result location for the start postion expressed in @format
1102 * @stop_type: (out): result location for the #GstSeekType of the stop position
1103 * @stop: (out): result location for the stop postion expressed in @format
1105 * Parses a seek @event and stores the results in the given result locations.
1108 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1109 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1110 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1112 const GstStructure *structure;
1114 g_return_if_fail (GST_IS_EVENT (event));
1115 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1117 structure = GST_EVENT_STRUCTURE (event);
1120 g_value_get_double (gst_structure_id_get_value (structure,
1123 *format = (GstFormat)
1124 g_value_get_enum (gst_structure_id_get_value (structure,
1125 GST_QUARK (FORMAT)));
1127 *flags = (GstSeekFlags)
1128 g_value_get_flags (gst_structure_id_get_value (structure,
1129 GST_QUARK (FLAGS)));
1131 *start_type = (GstSeekType)
1132 g_value_get_enum (gst_structure_id_get_value (structure,
1133 GST_QUARK (CUR_TYPE)));
1136 g_value_get_int64 (gst_structure_id_get_value (structure,
1139 *stop_type = (GstSeekType)
1140 g_value_get_enum (gst_structure_id_get_value (structure,
1141 GST_QUARK (STOP_TYPE)));
1144 g_value_get_int64 (gst_structure_id_get_value (structure,
1149 * gst_event_new_navigation:
1150 * @structure: (transfer full): description of the event. The event will take
1151 * ownership of the structure.
1153 * Create a new navigation event from the given description.
1155 * Returns: (transfer full): a new #GstEvent
1158 gst_event_new_navigation (GstStructure * structure)
1160 g_return_val_if_fail (structure != NULL, NULL);
1162 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1166 * gst_event_new_latency:
1167 * @latency: the new latency value
1169 * Create a new latency event. The event is sent upstream from the sinks and
1170 * notifies elements that they should add an additional @latency to the
1171 * running time before synchronising against the clock.
1173 * The latency is mostly used in live sinks and is always expressed in
1176 * Returns: (transfer full): a new #GstEvent
1179 gst_event_new_latency (GstClockTime latency)
1182 GstStructure *structure;
1184 GST_CAT_INFO (GST_CAT_EVENT,
1185 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1187 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1188 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1189 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1195 * gst_event_parse_latency:
1196 * @event: The event to query
1197 * @latency: (out): A pointer to store the latency in.
1199 * Get the latency in the latency event.
1202 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1204 g_return_if_fail (GST_IS_EVENT (event));
1205 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1209 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1210 (event), GST_QUARK (LATENCY)));
1214 * gst_event_new_step:
1215 * @format: the format of @amount
1216 * @amount: the amount of data to step
1217 * @rate: the step rate
1218 * @flush: flushing steps
1219 * @intermediate: intermediate steps
1221 * Create a new step event. The purpose of the step event is to instruct a sink
1222 * to skip @amount (expressed in @format) of media. It can be used to implement
1223 * stepping through the video frame by frame or for doing fast trick modes.
1225 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1226 * = 0.0 or first reverse the direction of playback using a seek event to get
1227 * the same effect as rate < 0.0.
1229 * The @flush flag will clear any pending data in the pipeline before starting
1230 * the step operation.
1232 * The @intermediate flag instructs the pipeline that this step operation is
1233 * part of a larger step operation.
1235 * Returns: (transfer full): a new #GstEvent
1238 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1239 gboolean flush, gboolean intermediate)
1242 GstStructure *structure;
1244 g_return_val_if_fail (rate > 0.0, NULL);
1246 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1248 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1249 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1250 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1251 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1252 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1253 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1254 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1260 * gst_event_parse_step:
1261 * @event: The event to query
1262 * @format: (out) (allow-none): a pointer to store the format in
1263 * @amount: (out) (allow-none): a pointer to store the amount in
1264 * @rate: (out) (allow-none): a pointer to store the rate in
1265 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1266 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1269 * Parse the step event.
1272 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1273 gdouble * rate, gboolean * flush, gboolean * intermediate)
1275 const GstStructure *structure;
1277 g_return_if_fail (GST_IS_EVENT (event));
1278 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1280 structure = GST_EVENT_STRUCTURE (event);
1283 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1284 GST_QUARK (FORMAT)));
1286 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1287 GST_QUARK (AMOUNT)));
1289 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1292 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1293 GST_QUARK (FLUSH)));
1295 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1296 GST_QUARK (INTERMEDIATE)));
1300 * gst_event_new_reconfigure:
1302 * Create a new reconfigure event. The purpose of the reconfingure event is
1303 * to travel upstream and make elements renegotiate their caps or reconfigure
1304 * their buffer pools. This is useful when changing properties on elements
1305 * or changing the topology of the pipeline.
1307 * Returns: (transfer full): a new #GstEvent
1310 gst_event_new_reconfigure (void)
1314 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1316 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1322 * gst_event_new_sink_message:
1323 * @name: a name for the event
1324 * @msg: (transfer none): the #GstMessage to be posted
1326 * Create a new sink-message event. The purpose of the sink-message event is
1327 * to instruct a sink to post the message contained in the event synchronized
1330 * @name is used to store multiple sticky events on one pad.
1332 * Returns: (transfer full): a new #GstEvent
1334 /* FIXME 0.11: take ownership of msg for consistency? */
1336 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1339 GstStructure *structure;
1341 g_return_val_if_fail (msg != NULL, NULL);
1343 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1345 structure = gst_structure_new_id (g_quark_from_string (name),
1346 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1347 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1353 * gst_event_parse_sink_message:
1354 * @event: The event to query
1355 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1357 * Parse the sink-message event. Unref @msg after usage.
1360 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1362 const GstStructure *structure;
1364 g_return_if_fail (GST_IS_EVENT (event));
1365 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1367 structure = GST_EVENT_STRUCTURE (event);
1370 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1371 (structure, GST_QUARK (MESSAGE))));
1375 * gst_event_new_stream_start:
1376 * @stream_id: Identifier for this stream
1378 * Create a new STREAM_START event. The stream start event can only
1379 * travel downstream synchronized with the buffer flow. It is expected
1380 * to be the first event that is sent for a new stream.
1382 * Source elements, demuxers and other elements that create new streams
1383 * are supposed to send this event as the first event of a new stream. It
1384 * should not be send after a flushing seek or in similar situations
1385 * and is used to mark the beginning of a new logical stream. Elements
1386 * combining multiple streams must ensure that this event is only forwarded
1387 * downstream once and not for every single input stream.
1389 * The @stream_id should be a unique string that consists of the upstream
1390 * stream-id, / as separator and a unique stream-id for this specific
1391 * stream. A new stream-id should only be created for a stream if the upstream
1392 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1393 * but not for every single element in the pipeline.
1394 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1395 * used to create a stream-id.
1397 * Returns: (transfer full): the new STREAM_START event.
1400 gst_event_new_stream_start (const gchar * stream_id)
1404 g_return_val_if_fail (stream_id != NULL, NULL);
1406 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1407 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1408 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1410 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1414 * gst_event_parse_stream_start:
1415 * @event: a stream-start event.
1416 * @stream_id: (out) (transfer none): pointer to store the stream-id
1418 * Parse a stream-id @event and store the result in the given @stream_id
1419 * location. The string stored in @stream_id must not be modified and will
1420 * remain valid only until @event gets freed. Make a copy if you want to
1421 * modify it or store it for later use.
1424 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1426 const GstStructure *structure;
1429 g_return_if_fail (event != NULL);
1430 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1432 structure = gst_event_get_structure (event);
1433 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1436 *stream_id = g_value_get_string (val);
1440 * gst_event_set_stream_flags:
1441 * @event: a stream-start event
1442 * @flags: the stream flags to set
1447 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1449 g_return_if_fail (event != NULL);
1450 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1451 g_return_if_fail (gst_event_is_writable (event));
1453 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1454 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1458 * gst_event_parse_stream_flags:
1459 * @event: a stream-start event
1460 * @flags: (out): address of variable where to store the stream flags
1465 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1467 g_return_if_fail (event != NULL);
1468 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1471 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1472 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1477 * gst_event_set_group_id:
1478 * @event: a stream-start event
1479 * @group_id: the group id to set
1481 * All streams that have the same group id are supposed to be played
1482 * together, i.e. all streams inside a container file should have the
1483 * same group id but different stream ids. The group id should change
1484 * each time the stream is started, resulting in different group ids
1485 * each time a file is played for example.
1487 * Use gst_util_group_id_next() to get a new group id.
1492 gst_event_set_group_id (GstEvent * event, guint group_id)
1494 g_return_if_fail (event != NULL);
1495 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1496 g_return_if_fail (gst_event_is_writable (event));
1498 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1499 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1503 * gst_event_parse_group_id:
1504 * @event: a stream-start event
1505 * @group_id: (out): address of variable where to store the group id
1507 * Returns: %TRUE if a group id was set on the event and could be parsed,
1513 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1515 g_return_val_if_fail (event != NULL, FALSE);
1516 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1520 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1521 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1528 * gst_event_new_toc:
1529 * @toc: (transfer none): #GstToc structure.
1530 * @updated: whether @toc was updated or not.
1532 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1533 * inform elements that some kind of the TOC was found.
1535 * Returns: (transfer full): a new #GstEvent.
1538 gst_event_new_toc (GstToc * toc, gboolean updated)
1540 GstStructure *toc_struct;
1543 g_return_val_if_fail (toc != NULL, NULL);
1545 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1547 /* need different structure names so sticky_multi event stuff on pads
1548 * works, i.e. both TOC events are kept around */
1549 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1550 id = GST_QUARK (EVENT_TOC_GLOBAL);
1552 id = GST_QUARK (EVENT_TOC_CURRENT);
1554 toc_struct = gst_structure_new_id (id,
1555 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1556 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1558 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1562 * gst_event_parse_toc:
1563 * @event: a TOC event.
1564 * @toc: (out) (transfer full): pointer to #GstToc structure.
1565 * @updated: (out): pointer to store TOC updated flag.
1567 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1570 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1572 const GstStructure *structure;
1574 g_return_if_fail (event != NULL);
1575 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1576 g_return_if_fail (toc != NULL);
1578 structure = gst_event_get_structure (event);
1580 gst_structure_id_get (structure,
1581 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1582 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1586 * gst_event_new_toc_select:
1587 * @uid: UID in the TOC to start playback from.
1589 * Generate a TOC select event with the given @uid. The purpose of the
1590 * TOC select event is to start playback based on the TOC's entry with the
1593 * Returns: a new #GstEvent.
1596 gst_event_new_toc_select (const gchar * uid)
1598 GstStructure *structure;
1600 g_return_val_if_fail (uid != NULL, NULL);
1602 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1604 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1605 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1607 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1611 * gst_event_parse_toc_select:
1612 * @event: a TOC select event.
1613 * @uid: (out): storage for the selection UID.
1615 * Parse a TOC select @event and store the results in the given @uid location.
1618 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1620 const GstStructure *structure;
1623 g_return_if_fail (event != NULL);
1624 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1626 structure = gst_event_get_structure (event);
1627 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1630 *uid = g_strdup (g_value_get_string (val));
1635 * gst_event_new_segment_done:
1636 * @format: The format of the position being done
1637 * @position: The position of the segment being done
1639 * Create a new segment-done event. This event is sent by elements that
1640 * finish playback of a segment as a result of a segment seek.
1642 * Returns: (transfer full): a new #GstEvent
1645 gst_event_new_segment_done (GstFormat format, gint64 position)
1648 GstStructure *structure;
1650 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
1652 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
1653 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1654 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
1656 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
1662 * gst_event_parse_segment_done:
1663 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
1664 * @format: (out) (allow-none): Result location for the format, or NULL
1665 * @position: (out) (allow-none): Result location for the position, or NULL
1667 * Extracts the position and format from the segment done message.
1671 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
1674 const GstStructure *structure;
1677 g_return_if_fail (event != NULL);
1678 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
1680 structure = gst_event_get_structure (event);
1682 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
1684 *format = g_value_get_enum (val);
1686 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
1687 if (position != NULL)
1688 *position = g_value_get_int64 (val);
1692 * gst_event_new_context:
1693 * @context: (transfer full): the #GstContext
1695 * Create a new context event. The purpose of the context event is
1696 * to pass a pipeline-local context to downstream elements.
1698 * Returns: (transfer full): a new #GstEvent
1703 gst_event_new_context (GstContext * context)
1706 GstStructure *structure;
1708 g_return_val_if_fail (context != NULL, NULL);
1710 GST_CAT_INFO (GST_CAT_EVENT, "creating context event");
1712 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1713 GST_QUARK (CONTEXT), GST_TYPE_CONTEXT, context, NULL);
1714 event = gst_event_new_custom (GST_EVENT_CONTEXT, structure);
1715 gst_context_unref (context);
1721 * gst_event_parse_context:
1722 * @event: The event to query
1723 * @context: (out) (transfer full): a pointer to store the #GstContext in.
1725 * Parse the context event. Unref @context after usage.
1730 gst_event_parse_context (GstEvent * event, GstContext ** context)
1732 const GstStructure *structure;
1734 g_return_if_fail (GST_IS_EVENT (event));
1735 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CONTEXT);
1737 structure = GST_EVENT_STRUCTURE (event);
1740 GST_CONTEXT (g_value_dup_boxed (gst_structure_id_get_value
1741 (structure, GST_QUARK (CONTEXT))));