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.
54 * |[<!-- language="C" -->
58 * // construct a seek event to play the media from second 2 to 5, flush
59 * // the pipeline to decrease latency.
60 * event = gst_event_new_seek (1.0,
62 * GST_SEEK_FLAG_FLUSH,
63 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
64 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
66 * result = gst_element_send_event (pipeline, event);
68 * g_warning ("seek failed");
74 #include "gst_private.h"
75 #include <string.h> /* memcpy */
79 #include "gstenumtypes.h"
84 GType _gst_event_type = 0;
90 GstStructure *structure;
91 gint64 running_time_offset;
94 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
103 static GstEventQuarks event_quarks[] = {
104 {GST_EVENT_UNKNOWN, "unknown", 0},
105 {GST_EVENT_FLUSH_START, "flush-start", 0},
106 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
107 {GST_EVENT_SELECT_STREAMS, "select-streams", 0},
108 {GST_EVENT_STREAM_START, "stream-start", 0},
109 {GST_EVENT_STREAM_COLLECTION, "stream-collection", 0},
110 {GST_EVENT_CAPS, "caps", 0},
111 {GST_EVENT_SEGMENT, "segment", 0},
112 {GST_EVENT_TAG, "tag", 0},
113 {GST_EVENT_TOC, "toc", 0},
114 {GST_EVENT_PROTECTION, "protection", 0},
115 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
116 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
117 {GST_EVENT_EOS, "eos", 0},
118 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
119 {GST_EVENT_GAP, "gap", 0},
120 {GST_EVENT_QOS, "qos", 0},
121 {GST_EVENT_SEEK, "seek", 0},
122 {GST_EVENT_NAVIGATION, "navigation", 0},
123 {GST_EVENT_LATENCY, "latency", 0},
124 {GST_EVENT_STEP, "step", 0},
125 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
126 {GST_EVENT_TOC_SELECT, "toc-select", 0},
127 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
128 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
129 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
130 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
131 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
132 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
137 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
140 _priv_gst_event_initialize (void)
144 _gst_event_type = gst_event_get_type ();
146 g_type_class_ref (gst_seek_flags_get_type ());
147 g_type_class_ref (gst_seek_type_get_type ());
149 for (i = 0; event_quarks[i].name; i++) {
150 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
155 * gst_event_type_get_name:
156 * @type: the event type
158 * Get a printable name for the given event type. Do not modify or free.
160 * Returns: a reference to the static name of the event.
163 gst_event_type_get_name (GstEventType type)
167 for (i = 0; event_quarks[i].name; i++) {
168 if (type == event_quarks[i].type)
169 return event_quarks[i].name;
175 * gst_event_type_to_quark:
176 * @type: the event type
178 * Get the unique quark for the given event type.
180 * Returns: the quark associated with the event type
183 gst_event_type_to_quark (GstEventType type)
187 for (i = 0; event_quarks[i].name; i++) {
188 if (type == event_quarks[i].type)
189 return event_quarks[i].quark;
195 * gst_event_type_get_flags:
196 * @type: a #GstEventType
198 * Gets the #GstEventTypeFlags associated with @type.
200 * Returns: a #GstEventTypeFlags.
203 gst_event_type_get_flags (GstEventType type)
205 GstEventTypeFlags ret;
207 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
213 _gst_event_free (GstEvent * event)
217 g_return_if_fail (event != NULL);
218 g_return_if_fail (GST_IS_EVENT (event));
220 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
221 GST_EVENT_TYPE_NAME (event));
223 s = GST_EVENT_STRUCTURE (event);
226 gst_structure_set_parent_refcount (s, NULL);
227 gst_structure_free (s);
230 g_slice_free1 (sizeof (GstEventImpl), event);
233 static void gst_event_init (GstEventImpl * event, GstEventType type);
236 _gst_event_copy (GstEvent * event)
241 copy = g_slice_new0 (GstEventImpl);
243 gst_event_init (copy, GST_EVENT_TYPE (event));
245 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
246 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
248 s = GST_EVENT_STRUCTURE (event);
250 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
251 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
252 ©->event.mini_object.refcount);
254 GST_EVENT_STRUCTURE (copy) = NULL;
257 ((GstEventImpl *) copy)->running_time_offset =
258 ((GstEventImpl *) event)->running_time_offset;
260 return GST_EVENT_CAST (copy);
264 gst_event_init (GstEventImpl * event, GstEventType type)
266 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
267 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
268 (GstMiniObjectFreeFunction) _gst_event_free);
270 GST_EVENT_TYPE (event) = type;
271 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
272 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
273 event->running_time_offset = 0;
278 * gst_event_new_custom:
279 * @type: The type of the new event
280 * @structure: (transfer full): the structure for the event. The event will
281 * take ownership of the structure.
283 * Create a new custom-typed event. This can be used for anything not
284 * handled by other event-specific functions to pass an event to another
287 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
288 * assigning a free number and filling in the correct direction and
289 * serialization flags.
291 * New custom events can also be created by subclassing the event type if
294 * Returns: (transfer full): the new custom event.
297 gst_event_new_custom (GstEventType type, GstStructure * structure)
301 event = g_slice_new0 (GstEventImpl);
303 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
304 gst_event_type_get_name (type), type);
307 /* structure must not have a parent */
308 if (!gst_structure_set_parent_refcount (structure,
309 &event->event.mini_object.refcount))
313 gst_event_init (event, type);
315 GST_EVENT_STRUCTURE (event) = structure;
317 return GST_EVENT_CAST (event);
322 g_slice_free1 (sizeof (GstEventImpl), event);
323 g_warning ("structure is already owned by another object");
329 * gst_event_get_structure:
330 * @event: The #GstEvent.
332 * Access the structure of the event.
334 * Returns: The structure of the event. The structure is still
335 * owned by the event, which means that you should not free it and
336 * that the pointer becomes invalid when you free the event.
341 gst_event_get_structure (GstEvent * event)
343 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
345 return GST_EVENT_STRUCTURE (event);
349 * gst_event_writable_structure:
350 * @event: The #GstEvent.
352 * Get a writable version of the structure.
354 * Returns: (transfer none): The structure of the event. The structure
355 * is still owned by the event, which means that you should not free
356 * it and that the pointer becomes invalid when you free the event.
357 * This function checks if @event is writable and will never return
363 gst_event_writable_structure (GstEvent * event)
365 GstStructure *structure;
367 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
368 g_return_val_if_fail (gst_event_is_writable (event), NULL);
370 structure = GST_EVENT_STRUCTURE (event);
372 if (structure == NULL) {
374 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
376 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
377 GST_EVENT_STRUCTURE (event) = structure;
383 * gst_event_has_name:
384 * @event: The #GstEvent.
385 * @name: name to check
387 * Checks if @event has the given @name. This function is usually used to
388 * check the name of a custom event.
390 * Returns: %TRUE if @name matches the name of the event structure.
393 gst_event_has_name (GstEvent * event, const gchar * name)
395 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
397 if (GST_EVENT_STRUCTURE (event) == NULL)
400 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
404 * gst_event_get_seqnum:
405 * @event: A #GstEvent.
407 * Retrieve the sequence number of a event.
409 * Events have ever-incrementing sequence numbers, which may also be set
410 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
411 * indicate that a event corresponds to some other set of events or messages,
412 * for example an EOS event corresponding to a SEEK event. It is considered good
413 * practice to make this correspondence when possible, though it is not
416 * Note that events and messages share the same sequence number incrementor;
417 * two events or messages will never have the same sequence number unless
418 * that correspondence was made explicitly.
420 * Returns: The event's sequence number.
425 gst_event_get_seqnum (GstEvent * event)
427 g_return_val_if_fail (GST_IS_EVENT (event), -1);
429 return GST_EVENT_SEQNUM (event);
433 * gst_event_set_seqnum:
434 * @event: A #GstEvent.
435 * @seqnum: A sequence number.
437 * Set the sequence number of a event.
439 * This function might be called by the creator of a event to indicate that the
440 * event relates to other events or messages. See gst_event_get_seqnum() for
446 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
448 g_return_if_fail (GST_IS_EVENT (event));
450 GST_EVENT_SEQNUM (event) = seqnum;
454 * gst_event_get_running_time_offset:
455 * @event: A #GstEvent.
457 * Retrieve the accumulated running time offset of the event.
459 * Events passing through #GstPads that have a running time
460 * offset set via gst_pad_set_offset() will get their offset
461 * adjusted according to the pad's offset.
463 * If the event contains any information that related to the
464 * running time, this information will need to be updated
465 * before usage with this offset.
467 * Returns: The event's running time offset
474 gst_event_get_running_time_offset (GstEvent * event)
476 g_return_val_if_fail (GST_IS_EVENT (event), 0);
478 return ((GstEventImpl *) event)->running_time_offset;
482 * gst_event_set_running_time_offset:
483 * @event: A #GstEvent.
484 * @offset: A the new running time offset
486 * Set the running time offset of a event. See
487 * gst_event_get_running_time_offset() for more information.
494 gst_event_set_running_time_offset (GstEvent * event, gint64 offset)
496 g_return_if_fail (GST_IS_EVENT (event));
498 ((GstEventImpl *) event)->running_time_offset = offset;
502 * gst_event_new_flush_start:
504 * Allocate a new flush start event. The flush start event can be sent
505 * upstream and downstream and travels out-of-bounds with the dataflow.
507 * It marks pads as being flushing and will make them return
508 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
509 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
510 * Any event (except a #GST_EVENT_FLUSH_STOP) received
511 * on a flushing pad will return %FALSE immediately.
513 * Elements should unlock any blocking functions and exit their streaming
514 * functions as fast as possible when this event is received.
516 * This event is typically generated after a seek to flush out all queued data
517 * in the pipeline so that the new media is played as soon as possible.
519 * Returns: (transfer full): a new flush start event.
522 gst_event_new_flush_start (void)
524 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
528 * gst_event_new_flush_stop:
529 * @reset_time: if time should be reset
531 * Allocate a new flush stop event. The flush stop event can be sent
532 * upstream and downstream and travels serialized with the dataflow.
533 * It is typically sent after sending a FLUSH_START event to make the
534 * pads accept data again.
536 * Elements can process this event synchronized with the dataflow since
537 * the preceding FLUSH_START event stopped the dataflow.
539 * This event is typically generated to complete a seek and to resume
542 * Returns: (transfer full): a new flush stop event.
545 gst_event_new_flush_stop (gboolean reset_time)
549 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
551 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
552 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
553 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
559 * gst_event_parse_flush_stop:
560 * @event: The event to parse
561 * @reset_time: (out): if time should be reset
563 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
566 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
568 GstStructure *structure;
570 g_return_if_fail (GST_IS_EVENT (event));
571 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
573 structure = GST_EVENT_STRUCTURE (event);
574 if (G_LIKELY (reset_time))
576 g_value_get_boolean (gst_structure_id_get_value (structure,
577 GST_QUARK (RESET_TIME)));
581 * gst_event_new_select_streams:
582 * @streams: (element-type gchar) (transfer none): the list of streams to
585 * Allocate a new select-streams event.
587 * The select-streams event requests the specified @streams to be activated.
589 * The list of @streams corresponds to the "Stream ID" of each stream to be
590 * activated. Those ID can be obtained via the #GstStream objects present
591 * in #GST_EVENT_STREAM_START, #GST_EVENT_STREAM_COLLECTION or
592 * #GST_MESSSAGE_STREAM_COLLECTION.
594 * Returns: (transfer full): a new select-streams event.
597 gst_event_new_select_streams (GList * streams)
600 GValue val = G_VALUE_INIT;
604 GST_CAT_INFO (GST_CAT_EVENT, "Creating new select-streams event");
605 struc = gst_structure_new_id_empty (GST_QUARK (EVENT_SELECT_STREAMS));
606 g_value_init (&val, GST_TYPE_LIST);
607 /* Fill struc with streams */
608 for (tmpl = streams; tmpl; tmpl = tmpl->next) {
609 GValue strval = G_VALUE_INIT;
610 const gchar *str = (const gchar *) tmpl->data;
611 g_value_init (&strval, G_TYPE_STRING);
612 g_value_set_string (&strval, str);
613 gst_value_list_append_and_take_value (&val, &strval);
615 gst_structure_id_take_value (struc, GST_QUARK (STREAMS), &val);
616 event = gst_event_new_custom (GST_EVENT_SELECT_STREAMS, struc);
622 * gst_event_parse_select_streams:
623 * @event: The event to parse
624 * @streams: (out) (element-type gchar) (transfer full): the streams
626 * Parse the SELECT_STREAMS event and retrieve the contained streams.
629 gst_event_parse_select_streams (GstEvent * event, GList ** streams)
631 GstStructure *structure;
634 g_return_if_fail (GST_IS_EVENT (event));
635 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SELECT_STREAMS);
637 structure = GST_EVENT_STRUCTURE (event);
638 if (G_LIKELY (streams)) {
639 const GValue *vlist =
640 gst_structure_id_get_value (structure, GST_QUARK (STREAMS));
641 guint i, sz = gst_value_list_get_size (vlist);
642 for (i = 0; i < sz; i++) {
643 const GValue *strv = gst_value_list_get_value (vlist, i);
644 res = g_list_append (res, g_value_dup_string (strv));
654 * Create a new EOS event. The eos event can only travel downstream
655 * synchronized with the buffer flow. Elements that receive the EOS
656 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
657 * when data after the EOS event arrives.
659 * The EOS event will travel down to the sink elements in the pipeline
660 * which will then post the #GST_MESSAGE_EOS on the bus after they have
661 * finished playing any buffered data.
663 * When all sinks have posted an EOS message, an EOS message is
664 * forwarded to the application.
666 * The EOS event itself will not cause any state transitions of the pipeline.
668 * Returns: (transfer full): the new EOS event.
671 gst_event_new_eos (void)
673 return gst_event_new_custom (GST_EVENT_EOS, NULL);
678 * @timestamp: the start time (pts) of the gap
679 * @duration: the duration of the gap
681 * Create a new GAP event. A gap event can be thought of as conceptually
682 * equivalent to a buffer to signal that there is no data for a certain
683 * amount of time. This is useful to signal a gap to downstream elements
684 * which may wait for data, such as muxers or mixers or overlays, especially
685 * for sparse streams such as subtitle streams.
687 * Returns: (transfer full): the new GAP event.
690 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
694 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
696 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
697 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
698 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
699 GST_TIME_ARGS (duration));
701 event = gst_event_new_custom (GST_EVENT_GAP,
702 gst_structure_new_id (GST_QUARK (EVENT_GAP),
703 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
704 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
710 * gst_event_parse_gap:
711 * @event: a #GstEvent of type #GST_EVENT_GAP
712 * @timestamp: (out) (allow-none): location where to store the
713 * start time (pts) of the gap, or %NULL
714 * @duration: (out) (allow-none): location where to store the duration of
717 * Extract timestamp and duration from a new GAP event.
720 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
721 GstClockTime * duration)
723 GstStructure *structure;
725 g_return_if_fail (GST_IS_EVENT (event));
726 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
728 structure = GST_EVENT_STRUCTURE (event);
729 gst_structure_id_get (structure,
730 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
731 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
735 * gst_event_new_caps:
736 * @caps: (transfer none): a #GstCaps
738 * Create a new CAPS event for @caps. The caps event can only travel downstream
739 * synchronized with the buffer flow and contains the format of the buffers
740 * that will follow after the event.
742 * Returns: (transfer full): the new CAPS event.
745 gst_event_new_caps (GstCaps * caps)
749 g_return_val_if_fail (caps != NULL, NULL);
750 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
752 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
754 event = gst_event_new_custom (GST_EVENT_CAPS,
755 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
756 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
762 * gst_event_parse_caps:
763 * @event: The event to parse
764 * @caps: (out) (transfer none): A pointer to the caps
766 * Get the caps from @event. The caps remains valid as long as @event remains
770 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
772 GstStructure *structure;
774 g_return_if_fail (GST_IS_EVENT (event));
775 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
777 structure = GST_EVENT_STRUCTURE (event);
780 g_value_get_boxed (gst_structure_id_get_value (structure,
785 * gst_event_new_segment:
786 * @segment: (transfer none): a #GstSegment
788 * Create a new SEGMENT event for @segment. The segment event can only travel
789 * downstream synchronized with the buffer flow and contains timing information
790 * and playback properties for the buffers that will follow.
792 * The segment event marks the range of buffers to be processed. All
793 * data not within the segment range is not to be processed. This can be
794 * used intelligently by plugins to apply more efficient methods of skipping
795 * unneeded data. The valid range is expressed with the @start and @stop
798 * The time value of the segment is used in conjunction with the start
799 * value to convert the buffer timestamps into the stream time. This is
800 * usually done in sinks to report the current stream_time.
801 * @time represents the stream_time of a buffer carrying a timestamp of
802 * @start. @time cannot be -1.
804 * @start cannot be -1, @stop can be -1. If there
805 * is a valid @stop given, it must be greater or equal the @start, including
806 * when the indicated playback @rate is < 0.
808 * The @applied_rate value provides information about any rate adjustment that
809 * has already been made to the timestamps and content on the buffers of the
810 * stream. (@rate * @applied_rate) should always equal the rate that has been
811 * requested for playback. For example, if an element has an input segment
812 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
813 * incoming timestamps and buffer content by half and output a segment event
814 * with @rate of 1.0 and @applied_rate of 2.0
816 * After a segment event, the buffer stream time is calculated with:
818 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
820 * Returns: (transfer full): the new SEGMENT event.
823 gst_event_new_segment (const GstSegment * segment)
827 g_return_val_if_fail (segment != NULL, NULL);
828 g_return_val_if_fail (segment->rate != 0.0, NULL);
829 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
830 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
832 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
835 event = gst_event_new_custom (GST_EVENT_SEGMENT,
836 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
837 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
843 * gst_event_parse_segment:
844 * @event: The event to parse
845 * @segment: (out) (transfer none): a pointer to a #GstSegment
847 * Parses a segment @event and stores the result in the given @segment location.
848 * @segment remains valid only until the @event is freed. Don't modify the segment
849 * and make a copy if you want to modify it or store it for later use.
852 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
854 GstStructure *structure;
856 g_return_if_fail (GST_IS_EVENT (event));
857 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
860 structure = GST_EVENT_STRUCTURE (event);
861 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
862 GST_QUARK (SEGMENT)));
867 * gst_event_copy_segment:
868 * @event: The event to parse
869 * @segment: a pointer to a #GstSegment
871 * Parses a segment @event and copies the #GstSegment into the location
875 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
877 const GstSegment *src;
879 g_return_if_fail (GST_IS_EVENT (event));
880 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
883 gst_event_parse_segment (event, &src);
884 gst_segment_copy_into (src, segment);
890 * @taglist: (transfer full): metadata list. The event will take ownership
893 * Generates a metadata tag event from the given @taglist.
895 * The scope of the taglist specifies if the taglist applies to the
896 * complete medium or only to this specific stream. As the tag event
897 * is a sticky event, elements should merge tags received from
898 * upstream with a given scope with their own tags with the same
899 * scope and create a new tag event from it.
901 * Returns: (transfer full): a new #GstEvent
904 gst_event_new_tag (GstTagList * taglist)
907 GValue val = G_VALUE_INIT;
908 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
910 g_return_val_if_fail (taglist != NULL, NULL);
912 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
913 g_value_init (&val, GST_TYPE_TAG_LIST);
914 g_value_take_boxed (&val, taglist);
915 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
916 return gst_event_new_custom (GST_EVENT_TAG, s);
920 * gst_event_parse_tag:
921 * @event: a tag event
922 * @taglist: (out) (transfer none): pointer to metadata list
924 * Parses a tag @event and stores the results in the given @taglist location.
925 * No reference to the taglist will be returned, it remains valid only until
926 * the @event is freed. Don't modify or free the taglist, make a copy if you
927 * want to modify it or store it for later use.
930 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
934 g_return_if_fail (GST_IS_EVENT (event));
935 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
937 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
938 GST_QUARK (TAGLIST));
941 *taglist = (GstTagList *) g_value_get_boxed (val);
944 /* buffersize event */
946 * gst_event_new_buffer_size:
947 * @format: buffer format
948 * @minsize: minimum buffer size
949 * @maxsize: maximum buffer size
950 * @async: thread behavior
952 * Create a new buffersize event. The event is sent downstream and notifies
953 * elements that they should provide a buffer of the specified dimensions.
955 * When the @async flag is set, a thread boundary is preferred.
957 * Returns: (transfer full): a new #GstEvent
960 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
961 gint64 maxsize, gboolean async)
964 GstStructure *structure;
966 GST_CAT_INFO (GST_CAT_EVENT,
967 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
968 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
969 minsize, maxsize, async);
971 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
972 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
973 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
974 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
975 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
976 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
982 * gst_event_parse_buffer_size:
983 * @event: The event to query
984 * @format: (out): A pointer to store the format in
985 * @minsize: (out): A pointer to store the minsize in
986 * @maxsize: (out): A pointer to store the maxsize in
987 * @async: (out): A pointer to store the async-flag in
989 * Get the format, minsize, maxsize and async-flag in the buffersize event.
992 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
993 gint64 * minsize, gint64 * maxsize, gboolean * async)
995 const GstStructure *structure;
997 g_return_if_fail (GST_IS_EVENT (event));
998 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1000 structure = GST_EVENT_STRUCTURE (event);
1002 *format = (GstFormat)
1003 g_value_get_enum (gst_structure_id_get_value (structure,
1004 GST_QUARK (FORMAT)));
1007 g_value_get_int64 (gst_structure_id_get_value (structure,
1008 GST_QUARK (MINSIZE)));
1011 g_value_get_int64 (gst_structure_id_get_value (structure,
1012 GST_QUARK (MAXSIZE)));
1015 g_value_get_boolean (gst_structure_id_get_value (structure,
1016 GST_QUARK (ASYNC)));
1020 * gst_event_new_qos:
1021 * @type: the QoS type
1022 * @proportion: the proportion of the qos message
1023 * @diff: The time difference of the last Clock sync
1024 * @timestamp: The timestamp of the buffer
1026 * Allocate a new qos event with the given values.
1027 * The QOS event is generated in an element that wants an upstream
1028 * element to either reduce or increase its rate because of
1029 * high/low CPU load or other resource usage such as network performance or
1030 * throttling. Typically sinks generate these events for each buffer
1033 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1034 * used when a buffer arrived in time or when the sink cannot keep up with
1035 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1036 * receiving buffers fast enough and thus has to drop late buffers.
1037 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1038 * by the application, for example to reduce power consumption.
1040 * @proportion indicates the real-time performance of the streaming in the
1041 * element that generated the QoS event (usually the sink). The value is
1042 * generally computed based on more long term statistics about the streams
1043 * timestamps compared to the clock.
1044 * A value < 1.0 indicates that the upstream element is producing data faster
1045 * than real-time. A value > 1.0 indicates that the upstream element is not
1046 * producing data fast enough. 1.0 is the ideal @proportion value. The
1047 * proportion value can safely be used to lower or increase the quality of
1050 * @diff is the difference against the clock in running time of the last
1051 * buffer that caused the element to generate the QOS event. A negative value
1052 * means that the buffer with @timestamp arrived in time. A positive value
1053 * indicates how late the buffer with @timestamp was. When throttling is
1054 * enabled, @diff will be set to the requested throttling interval.
1056 * @timestamp is the timestamp of the last buffer that cause the element
1057 * to generate the QOS event. It is expressed in running time and thus an ever
1060 * The upstream element can use the @diff and @timestamp values to decide
1061 * whether to process more buffers. For positive @diff, all buffers with
1062 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1063 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1064 * result smaller than 0 is not allowed.
1066 * The application can use general event probes to intercept the QoS
1067 * event and implement custom application specific QoS handling.
1069 * Returns: (transfer full): a new QOS event.
1072 gst_event_new_qos (GstQOSType type, gdouble proportion,
1073 GstClockTimeDiff diff, GstClockTime timestamp)
1076 GstStructure *structure;
1078 /* diff must be positive or timestamp + diff must be positive */
1079 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1081 GST_CAT_LOG (GST_CAT_EVENT,
1082 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1083 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1084 diff, GST_TIME_ARGS (timestamp));
1086 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1087 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1088 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1089 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1090 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1091 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1097 * gst_event_parse_qos:
1098 * @event: The event to query
1099 * @type: (out): A pointer to store the QoS type in
1100 * @proportion: (out): A pointer to store the proportion in
1101 * @diff: (out): A pointer to store the diff in
1102 * @timestamp: (out): A pointer to store the timestamp in
1104 * Get the type, proportion, diff and timestamp in the qos event. See
1105 * gst_event_new_qos() for more information about the different QoS values.
1107 * @timestamp will be adjusted for any pad offsets of pads it was passing through.
1110 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1111 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1113 const GstStructure *structure;
1115 g_return_if_fail (GST_IS_EVENT (event));
1116 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1118 structure = GST_EVENT_STRUCTURE (event);
1120 *type = (GstQOSType)
1121 g_value_get_enum (gst_structure_id_get_value (structure,
1125 g_value_get_double (gst_structure_id_get_value (structure,
1126 GST_QUARK (PROPORTION)));
1129 g_value_get_int64 (gst_structure_id_get_value (structure,
1132 gint64 offset = gst_event_get_running_time_offset (event);
1133 GstClockTimeDiff diff_ =
1134 g_value_get_int64 (gst_structure_id_get_value (structure,
1138 g_value_get_uint64 (gst_structure_id_get_value (structure,
1139 GST_QUARK (TIMESTAMP)));
1140 /* Catch underflows */
1141 if (*timestamp > -offset)
1142 *timestamp += offset;
1146 /* Make sure that timestamp + diff is always >= 0. Because
1147 * of the running time offset this might not be true */
1148 if (diff_ < 0 && *timestamp < -diff_)
1149 *timestamp = (GstClockTime) - diff_;
1154 * gst_event_new_seek:
1155 * @rate: The new playback rate
1156 * @format: The format of the seek values
1157 * @flags: The optional seek flags
1158 * @start_type: The type and flags for the new start position
1159 * @start: The value of the new start position
1160 * @stop_type: The type and flags for the new stop position
1161 * @stop: The value of the new stop position
1163 * Allocate a new seek event with the given parameters.
1165 * The seek event configures playback of the pipeline between @start to @stop
1166 * at the speed given in @rate, also called a playback segment.
1167 * The @start and @stop values are expressed in @format.
1169 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1170 * Negatives values means backwards playback. A value of 0.0 for the
1171 * rate is not allowed and should be accomplished instead by PAUSING the
1174 * A pipeline has a default playback segment configured with a start
1175 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1176 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1178 * @start_type and @stop_type specify how to adjust the currently configured
1179 * start and stop fields in playback segment. Adjustments can be made relative
1180 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1181 * means that the position should not be updated.
1183 * When the rate is positive and @start has been updated, playback will start
1184 * from the newly configured start position.
1186 * For negative rates, playback will start from the newly configured stop
1187 * position (if any). If the stop position is updated, it must be different from
1188 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1190 * It is not possible to seek relative to the current playback position, to do
1191 * this, PAUSE the pipeline, query the current playback position with
1192 * #GST_QUERY_POSITION and update the playback segment current position with a
1193 * #GST_SEEK_TYPE_SET to the desired position.
1195 * Returns: (transfer full): a new seek event.
1198 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1199 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1202 GstStructure *structure;
1204 g_return_val_if_fail (rate != 0.0, NULL);
1206 if (format == GST_FORMAT_TIME) {
1207 GST_CAT_INFO (GST_CAT_EVENT,
1208 "creating seek rate %lf, format TIME, flags %d, "
1209 "start_type %d, start %" GST_TIME_FORMAT ", "
1210 "stop_type %d, stop %" GST_TIME_FORMAT,
1211 rate, flags, start_type, GST_TIME_ARGS (start),
1212 stop_type, GST_TIME_ARGS (stop));
1214 GST_CAT_INFO (GST_CAT_EVENT,
1215 "creating seek rate %lf, format %s, flags %d, "
1216 "start_type %d, start %" G_GINT64_FORMAT ", "
1217 "stop_type %d, stop %" G_GINT64_FORMAT,
1218 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1222 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1223 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1224 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1225 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1226 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1227 GST_QUARK (CUR), G_TYPE_INT64, start,
1228 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1229 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1230 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1236 * gst_event_parse_seek:
1237 * @event: a seek event
1238 * @rate: (out): result location for the rate
1239 * @format: (out): result location for the stream format
1240 * @flags: (out): result location for the #GstSeekFlags
1241 * @start_type: (out): result location for the #GstSeekType of the start position
1242 * @start: (out): result location for the start position expressed in @format
1243 * @stop_type: (out): result location for the #GstSeekType of the stop position
1244 * @stop: (out): result location for the stop position expressed in @format
1246 * Parses a seek @event and stores the results in the given result locations.
1249 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1250 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1251 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1253 const GstStructure *structure;
1255 g_return_if_fail (GST_IS_EVENT (event));
1256 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1258 structure = GST_EVENT_STRUCTURE (event);
1261 g_value_get_double (gst_structure_id_get_value (structure,
1264 *format = (GstFormat)
1265 g_value_get_enum (gst_structure_id_get_value (structure,
1266 GST_QUARK (FORMAT)));
1268 *flags = (GstSeekFlags)
1269 g_value_get_flags (gst_structure_id_get_value (structure,
1270 GST_QUARK (FLAGS)));
1272 *start_type = (GstSeekType)
1273 g_value_get_enum (gst_structure_id_get_value (structure,
1274 GST_QUARK (CUR_TYPE)));
1277 g_value_get_int64 (gst_structure_id_get_value (structure,
1280 *stop_type = (GstSeekType)
1281 g_value_get_enum (gst_structure_id_get_value (structure,
1282 GST_QUARK (STOP_TYPE)));
1285 g_value_get_int64 (gst_structure_id_get_value (structure,
1290 * gst_event_new_navigation:
1291 * @structure: (transfer full): description of the event. The event will take
1292 * ownership of the structure.
1294 * Create a new navigation event from the given description.
1296 * Returns: (transfer full): a new #GstEvent
1299 gst_event_new_navigation (GstStructure * structure)
1301 g_return_val_if_fail (structure != NULL, NULL);
1303 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1307 * gst_event_new_latency:
1308 * @latency: the new latency value
1310 * Create a new latency event. The event is sent upstream from the sinks and
1311 * notifies elements that they should add an additional @latency to the
1312 * running time before synchronising against the clock.
1314 * The latency is mostly used in live sinks and is always expressed in
1317 * Returns: (transfer full): a new #GstEvent
1320 gst_event_new_latency (GstClockTime latency)
1323 GstStructure *structure;
1325 GST_CAT_INFO (GST_CAT_EVENT,
1326 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1328 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1329 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1330 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1336 * gst_event_parse_latency:
1337 * @event: The event to query
1338 * @latency: (out): A pointer to store the latency in.
1340 * Get the latency in the latency event.
1343 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1345 g_return_if_fail (GST_IS_EVENT (event));
1346 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1350 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1351 (event), GST_QUARK (LATENCY)));
1355 * gst_event_new_step:
1356 * @format: the format of @amount
1357 * @amount: the amount of data to step
1358 * @rate: the step rate
1359 * @flush: flushing steps
1360 * @intermediate: intermediate steps
1362 * Create a new step event. The purpose of the step event is to instruct a sink
1363 * to skip @amount (expressed in @format) of media. It can be used to implement
1364 * stepping through the video frame by frame or for doing fast trick modes.
1366 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1367 * = 0.0 or first reverse the direction of playback using a seek event to get
1368 * the same effect as rate < 0.0.
1370 * The @flush flag will clear any pending data in the pipeline before starting
1371 * the step operation.
1373 * The @intermediate flag instructs the pipeline that this step operation is
1374 * part of a larger step operation.
1376 * Returns: (transfer full): a new #GstEvent
1379 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1380 gboolean flush, gboolean intermediate)
1383 GstStructure *structure;
1385 g_return_val_if_fail (rate > 0.0, NULL);
1387 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1389 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1390 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1391 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1392 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1393 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1394 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1395 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1401 * gst_event_parse_step:
1402 * @event: The event to query
1403 * @format: (out) (allow-none): a pointer to store the format in
1404 * @amount: (out) (allow-none): a pointer to store the amount in
1405 * @rate: (out) (allow-none): a pointer to store the rate in
1406 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1407 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1410 * Parse the step event.
1413 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1414 gdouble * rate, gboolean * flush, gboolean * intermediate)
1416 const GstStructure *structure;
1418 g_return_if_fail (GST_IS_EVENT (event));
1419 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1421 structure = GST_EVENT_STRUCTURE (event);
1424 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1425 GST_QUARK (FORMAT)));
1427 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1428 GST_QUARK (AMOUNT)));
1430 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1433 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1434 GST_QUARK (FLUSH)));
1436 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1437 GST_QUARK (INTERMEDIATE)));
1441 * gst_event_new_reconfigure:
1443 * Create a new reconfigure event. The purpose of the reconfigure event is
1444 * to travel upstream and make elements renegotiate their caps or reconfigure
1445 * their buffer pools. This is useful when changing properties on elements
1446 * or changing the topology of the pipeline.
1448 * Returns: (transfer full): a new #GstEvent
1451 gst_event_new_reconfigure (void)
1455 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1457 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1463 * gst_event_new_sink_message:
1464 * @name: a name for the event
1465 * @msg: (transfer none): the #GstMessage to be posted
1467 * Create a new sink-message event. The purpose of the sink-message event is
1468 * to instruct a sink to post the message contained in the event synchronized
1471 * @name is used to store multiple sticky events on one pad.
1473 * Returns: (transfer full): a new #GstEvent
1475 /* FIXME 2.0: take ownership of msg for consistency? */
1477 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1480 GstStructure *structure;
1482 g_return_val_if_fail (msg != NULL, NULL);
1484 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1486 structure = gst_structure_new_id (g_quark_from_string (name),
1487 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1488 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1494 * gst_event_parse_sink_message:
1495 * @event: The event to query
1496 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1498 * Parse the sink-message event. Unref @msg after usage.
1501 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1503 const GstStructure *structure;
1505 g_return_if_fail (GST_IS_EVENT (event));
1506 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1508 structure = GST_EVENT_STRUCTURE (event);
1511 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1512 (structure, GST_QUARK (MESSAGE))));
1516 * gst_event_new_stream_start:
1517 * @stream_id: Identifier for this stream
1519 * Create a new STREAM_START event. The stream start event can only
1520 * travel downstream synchronized with the buffer flow. It is expected
1521 * to be the first event that is sent for a new stream.
1523 * Source elements, demuxers and other elements that create new streams
1524 * are supposed to send this event as the first event of a new stream. It
1525 * should not be sent after a flushing seek or in similar situations
1526 * and is used to mark the beginning of a new logical stream. Elements
1527 * combining multiple streams must ensure that this event is only forwarded
1528 * downstream once and not for every single input stream.
1530 * The @stream_id should be a unique string that consists of the upstream
1531 * stream-id, / as separator and a unique stream-id for this specific
1532 * stream. A new stream-id should only be created for a stream if the upstream
1533 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1534 * but not for every single element in the pipeline.
1535 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1536 * used to create a stream-id. There are no particular semantics for the
1537 * stream-id, though it should be deterministic (to support stream matching)
1538 * and it might be used to order streams (besides any information conveyed by
1541 * Returns: (transfer full): the new STREAM_START event.
1544 gst_event_new_stream_start (const gchar * stream_id)
1548 g_return_val_if_fail (stream_id != NULL, NULL);
1550 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1551 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1552 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1554 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1558 * gst_event_parse_stream_start:
1559 * @event: a stream-start event.
1560 * @stream_id: (out) (transfer none): pointer to store the stream-id
1562 * Parse a stream-id @event and store the result in the given @stream_id
1563 * location. The string stored in @stream_id must not be modified and will
1564 * remain valid only until @event gets freed. Make a copy if you want to
1565 * modify it or store it for later use.
1568 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1570 const GstStructure *structure;
1573 g_return_if_fail (event != NULL);
1574 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1576 structure = gst_event_get_structure (event);
1577 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1580 *stream_id = g_value_get_string (val);
1584 * gst_event_set_stream:
1585 * @event: a stream-start event
1586 * @stream: (transfer none): the stream object to set
1588 * Set the @stream on the stream-start @event
1591 gst_event_set_stream (GstEvent * event, GstStream * stream)
1593 g_return_if_fail (event != NULL);
1594 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1595 g_return_if_fail (gst_event_is_writable (event));
1597 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1598 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1602 * gst_event_parse_stream:
1603 * @event: a stream-start event
1604 * @stream: (out) (transfer full): adress of variable to store the stream
1606 * Parse a stream-start @event and extract the #GstStream from it.
1609 gst_event_parse_stream (GstEvent * event, GstStream ** stream)
1611 g_return_if_fail (event != NULL);
1612 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1615 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1616 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1622 * gst_event_set_stream_flags:
1623 * @event: a stream-start event
1624 * @flags: the stream flags to set
1629 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1631 g_return_if_fail (event != NULL);
1632 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1633 g_return_if_fail (gst_event_is_writable (event));
1635 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1636 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1640 * gst_event_parse_stream_flags:
1641 * @event: a stream-start event
1642 * @flags: (out): address of variable where to store the stream flags
1647 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1649 g_return_if_fail (event != NULL);
1650 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1653 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1654 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1659 * gst_event_set_group_id:
1660 * @event: a stream-start event
1661 * @group_id: the group id to set
1663 * All streams that have the same group id are supposed to be played
1664 * together, i.e. all streams inside a container file should have the
1665 * same group id but different stream ids. The group id should change
1666 * each time the stream is started, resulting in different group ids
1667 * each time a file is played for example.
1669 * Use gst_util_group_id_next() to get a new group id.
1674 gst_event_set_group_id (GstEvent * event, guint group_id)
1676 g_return_if_fail (event != NULL);
1677 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1678 g_return_if_fail (gst_event_is_writable (event));
1680 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1681 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1685 * gst_event_parse_group_id:
1686 * @event: a stream-start event
1687 * @group_id: (out): address of variable where to store the group id
1689 * Returns: %TRUE if a group id was set on the event and could be parsed,
1695 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1697 g_return_val_if_fail (event != NULL, FALSE);
1698 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1702 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1703 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1710 * gst_event_new_stream_collection:
1711 * @collection: Active collection for this data flow
1713 * Create a new STREAM_COLLECTION event. The stream collection event can only
1714 * travel downstream synchronized with the buffer flow.
1716 * Source elements, demuxers and other elements that manage collections
1717 * of streams and post #GstStreamCollection messages on the bus also send
1718 * this event downstream on each pad involved in the collection, so that
1719 * activation of a new collection can be tracked through the downstream
1722 * Returns: (transfer full): the new STREAM_COLLECTION event.
1725 gst_event_new_stream_collection (GstStreamCollection * collection)
1729 g_return_val_if_fail (collection != NULL, NULL);
1730 g_return_val_if_fail (GST_IS_STREAM_COLLECTION (collection), NULL);
1732 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_COLLECTION),
1733 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1735 return gst_event_new_custom (GST_EVENT_STREAM_COLLECTION, s);
1739 gst_event_parse_stream_collection (GstEvent * event,
1740 GstStreamCollection ** collection)
1742 const GstStructure *structure;
1744 g_return_if_fail (event != NULL);
1745 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_COLLECTION);
1747 structure = gst_event_get_structure (event);
1750 gst_structure_id_get (structure,
1751 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1756 * gst_event_new_toc:
1757 * @toc: (transfer none): #GstToc structure.
1758 * @updated: whether @toc was updated or not.
1760 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1761 * inform elements that some kind of the TOC was found.
1763 * Returns: (transfer full): a new #GstEvent.
1766 gst_event_new_toc (GstToc * toc, gboolean updated)
1768 GstStructure *toc_struct;
1771 g_return_val_if_fail (toc != NULL, NULL);
1773 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1775 /* need different structure names so sticky_multi event stuff on pads
1776 * works, i.e. both TOC events are kept around */
1777 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1778 id = GST_QUARK (EVENT_TOC_GLOBAL);
1780 id = GST_QUARK (EVENT_TOC_CURRENT);
1782 toc_struct = gst_structure_new_id (id,
1783 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1784 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1786 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1790 * gst_event_parse_toc:
1791 * @event: a TOC event.
1792 * @toc: (out) (transfer full): pointer to #GstToc structure.
1793 * @updated: (out): pointer to store TOC updated flag.
1795 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1798 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1800 const GstStructure *structure;
1802 g_return_if_fail (event != NULL);
1803 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1804 g_return_if_fail (toc != NULL);
1806 structure = gst_event_get_structure (event);
1808 gst_structure_id_get (structure,
1809 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1810 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1814 * gst_event_new_toc_select:
1815 * @uid: UID in the TOC to start playback from.
1817 * Generate a TOC select event with the given @uid. The purpose of the
1818 * TOC select event is to start playback based on the TOC's entry with the
1821 * Returns: a new #GstEvent.
1824 gst_event_new_toc_select (const gchar * uid)
1826 GstStructure *structure;
1828 g_return_val_if_fail (uid != NULL, NULL);
1830 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1832 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1833 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1835 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1839 * gst_event_parse_toc_select:
1840 * @event: a TOC select event.
1841 * @uid: (out) (transfer full) (allow-none): storage for the selection UID.
1843 * Parse a TOC select @event and store the results in the given @uid location.
1846 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1848 const GstStructure *structure;
1851 g_return_if_fail (event != NULL);
1852 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1854 structure = gst_event_get_structure (event);
1855 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1858 *uid = g_strdup (g_value_get_string (val));
1863 * gst_event_new_protection:
1864 * @system_id: (transfer none): a string holding a UUID that uniquely
1865 * identifies a protection system.
1866 * @data: (transfer none): a #GstBuffer holding protection system specific
1867 * information. The reference count of the buffer will be incremented by one.
1868 * @origin: a string indicating where the protection
1869 * information carried in the event was extracted from. The allowed values
1870 * of this string will depend upon the protection scheme.
1872 * Creates a new event containing information specific to a particular
1873 * protection system (uniquely identified by @system_id), by which that
1874 * protection system can acquire key(s) to decrypt a protected stream.
1876 * In order for a decryption element to decrypt media
1877 * protected using a specific system, it first needs all the
1878 * protection system specific information necessary to acquire the decryption
1879 * key(s) for that stream. The functions defined here enable this information
1880 * to be passed in events from elements that extract it
1881 * (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter
1882 * elements that use it.
1884 * Events containing protection system specific information are created using
1885 * #gst_event_new_protection, and they can be parsed by downstream elements
1886 * using #gst_event_parse_protection.
1888 * In Common Encryption, protection system specific information may be located
1889 * within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof)
1890 * boxes; it may also be contained in ContentProtection elements within MPEG
1891 * DASH MPDs. The events created by #gst_event_new_protection contain data
1892 * identifying from which of these locations the encapsulated protection system
1893 * specific information originated. This origin information is required as
1894 * some protection systems use different encodings depending upon where the
1895 * information originates.
1897 * The events returned by gst_event_new_protection() are implemented
1898 * in such a way as to ensure that the most recently-pushed protection info
1899 * event of a particular @origin and @system_id will
1900 * be stuck to the output pad of the sending element.
1902 * Returns: a #GST_EVENT_PROTECTION event, if successful; %NULL
1908 gst_event_new_protection (const gchar * system_id,
1909 GstBuffer * data, const gchar * origin)
1915 g_return_val_if_fail (system_id != NULL, NULL);
1916 g_return_val_if_fail (data != NULL, NULL);
1919 g_strconcat ("GstProtectionEvent", origin ? "-" : "",
1920 origin ? origin : "", "-", system_id, NULL);
1922 GST_CAT_INFO (GST_CAT_EVENT, "creating protection event %s", event_name);
1924 s = gst_structure_new (event_name, "data", GST_TYPE_BUFFER, data,
1925 "system_id", G_TYPE_STRING, system_id, NULL);
1927 gst_structure_set (s, "origin", G_TYPE_STRING, origin, NULL);
1928 event = gst_event_new_custom (GST_EVENT_PROTECTION, s);
1930 g_free (event_name);
1935 * gst_event_parse_protection:
1936 * @event: a #GST_EVENT_PROTECTION event.
1937 * @system_id: (out) (allow-none) (transfer none): pointer to store the UUID
1938 * string uniquely identifying a content protection system.
1939 * @data: (out) (allow-none) (transfer none): pointer to store a #GstBuffer
1940 * holding protection system specific information.
1941 * @origin: (allow-none) (transfer none): pointer to store a value that
1942 * indicates where the protection information carried by @event was extracted
1945 * Parses an event containing protection system specific information and stores
1946 * the results in @system_id, @data and @origin. The data stored in @system_id,
1947 * @origin and @data are valid until @event is released.
1952 gst_event_parse_protection (GstEvent * event, const gchar ** system_id,
1953 GstBuffer ** data, const gchar ** origin)
1955 const GstStructure *s;
1957 g_return_if_fail (event != NULL);
1958 g_return_if_fail (GST_IS_EVENT (event));
1959 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_PROTECTION);
1961 s = gst_event_get_structure (event);
1964 *origin = gst_structure_get_string (s, "origin");
1967 *system_id = gst_structure_get_string (s, "system_id");
1970 const GValue *value = gst_structure_get_value (s, "data");
1971 *data = gst_value_get_buffer (value);
1976 * gst_event_new_segment_done:
1977 * @format: The format of the position being done
1978 * @position: The position of the segment being done
1980 * Create a new segment-done event. This event is sent by elements that
1981 * finish playback of a segment as a result of a segment seek.
1983 * Returns: (transfer full): a new #GstEvent
1986 gst_event_new_segment_done (GstFormat format, gint64 position)
1989 GstStructure *structure;
1991 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
1993 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
1994 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1995 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
1997 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
2003 * gst_event_parse_segment_done:
2004 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
2005 * @format: (out) (allow-none): Result location for the format, or %NULL
2006 * @position: (out) (allow-none): Result location for the position, or %NULL
2008 * Extracts the position and format from the segment done message.
2012 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
2015 const GstStructure *structure;
2018 g_return_if_fail (event != NULL);
2019 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
2021 structure = gst_event_get_structure (event);
2023 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
2025 *format = g_value_get_enum (val);
2027 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
2028 if (position != NULL)
2029 *position = g_value_get_int64 (val);