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},
133 {GST_EVENT_STREAM_GROUP_DONE, "stream-group-done", 0},
138 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
141 _priv_gst_event_initialize (void)
145 _gst_event_type = gst_event_get_type ();
147 g_type_class_ref (gst_seek_flags_get_type ());
148 g_type_class_ref (gst_seek_type_get_type ());
150 for (i = 0; event_quarks[i].name; i++) {
151 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
156 * gst_event_type_get_name:
157 * @type: the event type
159 * Get a printable name for the given event type. Do not modify or free.
161 * Returns: a reference to the static name of the event.
164 gst_event_type_get_name (GstEventType type)
168 for (i = 0; event_quarks[i].name; i++) {
169 if (type == event_quarks[i].type)
170 return event_quarks[i].name;
176 * gst_event_type_to_quark:
177 * @type: the event type
179 * Get the unique quark for the given event type.
181 * Returns: the quark associated with the event type
184 gst_event_type_to_quark (GstEventType type)
188 for (i = 0; event_quarks[i].name; i++) {
189 if (type == event_quarks[i].type)
190 return event_quarks[i].quark;
196 * gst_event_type_get_flags:
197 * @type: a #GstEventType
199 * Gets the #GstEventTypeFlags associated with @type.
201 * Returns: a #GstEventTypeFlags.
204 gst_event_type_get_flags (GstEventType type)
206 GstEventTypeFlags ret;
208 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
214 _gst_event_free (GstEvent * event)
218 g_return_if_fail (event != NULL);
219 g_return_if_fail (GST_IS_EVENT (event));
221 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
222 GST_EVENT_TYPE_NAME (event));
224 s = GST_EVENT_STRUCTURE (event);
227 gst_structure_set_parent_refcount (s, NULL);
228 gst_structure_free (s);
231 g_slice_free1 (sizeof (GstEventImpl), event);
234 static void gst_event_init (GstEventImpl * event, GstEventType type);
237 _gst_event_copy (GstEvent * event)
242 copy = g_slice_new0 (GstEventImpl);
244 gst_event_init (copy, GST_EVENT_TYPE (event));
246 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
247 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
249 s = GST_EVENT_STRUCTURE (event);
251 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
252 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
253 ©->event.mini_object.refcount);
255 GST_EVENT_STRUCTURE (copy) = NULL;
258 ((GstEventImpl *) copy)->running_time_offset =
259 ((GstEventImpl *) event)->running_time_offset;
261 return GST_EVENT_CAST (copy);
265 gst_event_init (GstEventImpl * event, GstEventType type)
267 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
268 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
269 (GstMiniObjectFreeFunction) _gst_event_free);
271 GST_EVENT_TYPE (event) = type;
272 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
273 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
274 event->running_time_offset = 0;
279 * gst_event_new_custom:
280 * @type: The type of the new event
281 * @structure: (transfer full): the structure for the event. The event will
282 * take ownership of the structure.
284 * Create a new custom-typed event. This can be used for anything not
285 * handled by other event-specific functions to pass an event to another
288 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
289 * assigning a free number and filling in the correct direction and
290 * serialization flags.
292 * New custom events can also be created by subclassing the event type if
295 * Returns: (transfer full): the new custom event.
298 gst_event_new_custom (GstEventType type, GstStructure * structure)
302 event = g_slice_new0 (GstEventImpl);
304 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
305 gst_event_type_get_name (type), type);
308 /* structure must not have a parent */
309 if (!gst_structure_set_parent_refcount (structure,
310 &event->event.mini_object.refcount))
314 gst_event_init (event, type);
316 GST_EVENT_STRUCTURE (event) = structure;
318 return GST_EVENT_CAST (event);
323 g_slice_free1 (sizeof (GstEventImpl), event);
324 g_warning ("structure is already owned by another object");
330 * gst_event_get_structure:
331 * @event: The #GstEvent.
333 * Access the structure of the event.
335 * Returns: The structure of the event. The structure is still
336 * owned by the event, which means that you should not free it and
337 * that the pointer becomes invalid when you free the event.
342 gst_event_get_structure (GstEvent * event)
344 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
346 return GST_EVENT_STRUCTURE (event);
350 * gst_event_writable_structure:
351 * @event: The #GstEvent.
353 * Get a writable version of the structure.
355 * Returns: (transfer none): The structure of the event. The structure
356 * is still owned by the event, which means that you should not free
357 * it and that the pointer becomes invalid when you free the event.
358 * This function checks if @event is writable and will never return
364 gst_event_writable_structure (GstEvent * event)
366 GstStructure *structure;
368 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
369 g_return_val_if_fail (gst_event_is_writable (event), NULL);
371 structure = GST_EVENT_STRUCTURE (event);
373 if (structure == NULL) {
375 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
377 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
378 GST_EVENT_STRUCTURE (event) = structure;
384 * gst_event_has_name:
385 * @event: The #GstEvent.
386 * @name: name to check
388 * Checks if @event has the given @name. This function is usually used to
389 * check the name of a custom event.
391 * Returns: %TRUE if @name matches the name of the event structure.
394 gst_event_has_name (GstEvent * event, const gchar * name)
396 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
398 if (GST_EVENT_STRUCTURE (event) == NULL)
401 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
405 * gst_event_get_seqnum:
406 * @event: A #GstEvent.
408 * Retrieve the sequence number of a event.
410 * Events have ever-incrementing sequence numbers, which may also be set
411 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
412 * indicate that a event corresponds to some other set of events or messages,
413 * for example an EOS event corresponding to a SEEK event. It is considered good
414 * practice to make this correspondence when possible, though it is not
417 * Note that events and messages share the same sequence number incrementor;
418 * two events or messages will never have the same sequence number unless
419 * that correspondence was made explicitly.
421 * Returns: The event's sequence number.
426 gst_event_get_seqnum (GstEvent * event)
428 g_return_val_if_fail (GST_IS_EVENT (event), -1);
430 return GST_EVENT_SEQNUM (event);
434 * gst_event_set_seqnum:
435 * @event: A #GstEvent.
436 * @seqnum: A sequence number.
438 * Set the sequence number of a event.
440 * This function might be called by the creator of a event to indicate that the
441 * event relates to other events or messages. See gst_event_get_seqnum() for
447 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
449 g_return_if_fail (GST_IS_EVENT (event));
451 GST_EVENT_SEQNUM (event) = seqnum;
455 * gst_event_get_running_time_offset:
456 * @event: A #GstEvent.
458 * Retrieve the accumulated running time offset of the event.
460 * Events passing through #GstPads that have a running time
461 * offset set via gst_pad_set_offset() will get their offset
462 * adjusted according to the pad's offset.
464 * If the event contains any information that related to the
465 * running time, this information will need to be updated
466 * before usage with this offset.
468 * Returns: The event's running time offset
475 gst_event_get_running_time_offset (GstEvent * event)
477 g_return_val_if_fail (GST_IS_EVENT (event), 0);
479 return ((GstEventImpl *) event)->running_time_offset;
483 * gst_event_set_running_time_offset:
484 * @event: A #GstEvent.
485 * @offset: A the new running time offset
487 * Set the running time offset of a event. See
488 * gst_event_get_running_time_offset() for more information.
495 gst_event_set_running_time_offset (GstEvent * event, gint64 offset)
497 g_return_if_fail (GST_IS_EVENT (event));
499 ((GstEventImpl *) event)->running_time_offset = offset;
503 * gst_event_new_flush_start:
505 * Allocate a new flush start event. The flush start event can be sent
506 * upstream and downstream and travels out-of-bounds with the dataflow.
508 * It marks pads as being flushing and will make them return
509 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
510 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
511 * Any event (except a #GST_EVENT_FLUSH_STOP) received
512 * on a flushing pad will return %FALSE immediately.
514 * Elements should unlock any blocking functions and exit their streaming
515 * functions as fast as possible when this event is received.
517 * This event is typically generated after a seek to flush out all queued data
518 * in the pipeline so that the new media is played as soon as possible.
520 * Returns: (transfer full): a new flush start event.
523 gst_event_new_flush_start (void)
525 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
529 * gst_event_new_flush_stop:
530 * @reset_time: if time should be reset
532 * Allocate a new flush stop event. The flush stop event can be sent
533 * upstream and downstream and travels serialized with the dataflow.
534 * It is typically sent after sending a FLUSH_START event to make the
535 * pads accept data again.
537 * Elements can process this event synchronized with the dataflow since
538 * the preceding FLUSH_START event stopped the dataflow.
540 * This event is typically generated to complete a seek and to resume
543 * Returns: (transfer full): a new flush stop event.
546 gst_event_new_flush_stop (gboolean reset_time)
550 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
552 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
553 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
554 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
560 * gst_event_parse_flush_stop:
561 * @event: The event to parse
562 * @reset_time: (out): if time should be reset
564 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
567 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
569 GstStructure *structure;
571 g_return_if_fail (GST_IS_EVENT (event));
572 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
574 structure = GST_EVENT_STRUCTURE (event);
575 if (G_LIKELY (reset_time))
577 g_value_get_boolean (gst_structure_id_get_value (structure,
578 GST_QUARK (RESET_TIME)));
582 * gst_event_new_select_streams:
583 * @streams: (element-type utf8) (transfer none): the list of streams to
586 * Allocate a new select-streams event.
588 * The select-streams event requests the specified @streams to be activated.
590 * The list of @streams corresponds to the "Stream ID" of each stream to be
591 * activated. Those ID can be obtained via the #GstStream objects present
592 * in #GST_EVENT_STREAM_START, #GST_EVENT_STREAM_COLLECTION or
593 * #GST_MESSSAGE_STREAM_COLLECTION.
595 * Returns: (transfer full): a new select-streams event.
600 gst_event_new_select_streams (GList * streams)
603 GValue val = G_VALUE_INIT;
607 GST_CAT_INFO (GST_CAT_EVENT, "Creating new select-streams event");
608 struc = gst_structure_new_id_empty (GST_QUARK (EVENT_SELECT_STREAMS));
609 g_value_init (&val, GST_TYPE_LIST);
610 /* Fill struc with streams */
611 for (tmpl = streams; tmpl; tmpl = tmpl->next) {
612 GValue strval = G_VALUE_INIT;
613 const gchar *str = (const gchar *) tmpl->data;
614 g_value_init (&strval, G_TYPE_STRING);
615 g_value_set_string (&strval, str);
616 gst_value_list_append_and_take_value (&val, &strval);
618 gst_structure_id_take_value (struc, GST_QUARK (STREAMS), &val);
619 event = gst_event_new_custom (GST_EVENT_SELECT_STREAMS, struc);
625 * gst_event_parse_select_streams:
626 * @event: The event to parse
627 * @streams: (out) (element-type utf8) (transfer full): the streams
629 * Parse the SELECT_STREAMS event and retrieve the contained streams.
634 gst_event_parse_select_streams (GstEvent * event, GList ** streams)
636 GstStructure *structure;
639 g_return_if_fail (GST_IS_EVENT (event));
640 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SELECT_STREAMS);
642 structure = GST_EVENT_STRUCTURE (event);
643 if (G_LIKELY (streams)) {
644 const GValue *vlist =
645 gst_structure_id_get_value (structure, GST_QUARK (STREAMS));
646 guint i, sz = gst_value_list_get_size (vlist);
647 for (i = 0; i < sz; i++) {
648 const GValue *strv = gst_value_list_get_value (vlist, i);
649 res = g_list_append (res, g_value_dup_string (strv));
657 * gst_event_new_stream_group_done:
658 * @group_id: the group id of the stream group which is ending
660 * Create a new Stream Group Done event. The stream-group-done event can
661 * only travel downstream synchronized with the buffer flow. Elements
662 * that receive the event on a pad should handle it mostly like EOS,
663 * and emit any data or pending buffers that would depend on more data
664 * arriving and unblock, since there won't be any more data.
666 * This event is followed by EOS at some point in the future, and is
667 * generally used when switching pads - to unblock downstream so that
668 * new pads can be exposed before sending EOS on the existing pads.
670 * Returns: (transfer full): the new stream-group-done event.
675 gst_event_new_stream_group_done (guint group_id)
679 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_GROUP_DONE),
680 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
682 return gst_event_new_custom (GST_EVENT_STREAM_GROUP_DONE, s);
686 * gst_event_parse_stream_group_done:
687 * @event: a stream-group-done event.
688 * @group_id: (out): address of variable to store the group id into
690 * Parse a stream-group-done @event and store the result in the given
691 * @group_id location.
696 gst_event_parse_stream_group_done (GstEvent * event, guint * group_id)
698 g_return_if_fail (event != NULL);
699 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_GROUP_DONE);
702 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
703 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
710 * Create a new EOS event. The eos event can only travel downstream
711 * synchronized with the buffer flow. Elements that receive the EOS
712 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
713 * when data after the EOS event arrives.
715 * The EOS event will travel down to the sink elements in the pipeline
716 * which will then post the #GST_MESSAGE_EOS on the bus after they have
717 * finished playing any buffered data.
719 * When all sinks have posted an EOS message, an EOS message is
720 * forwarded to the application.
722 * The EOS event itself will not cause any state transitions of the pipeline.
724 * Returns: (transfer full): the new EOS event.
727 gst_event_new_eos (void)
729 return gst_event_new_custom (GST_EVENT_EOS, NULL);
734 * @timestamp: the start time (pts) of the gap
735 * @duration: the duration of the gap
737 * Create a new GAP event. A gap event can be thought of as conceptually
738 * equivalent to a buffer to signal that there is no data for a certain
739 * amount of time. This is useful to signal a gap to downstream elements
740 * which may wait for data, such as muxers or mixers or overlays, especially
741 * for sparse streams such as subtitle streams.
743 * Returns: (transfer full): the new GAP event.
746 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
750 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
752 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
753 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
754 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
755 GST_TIME_ARGS (duration));
757 event = gst_event_new_custom (GST_EVENT_GAP,
758 gst_structure_new_id (GST_QUARK (EVENT_GAP),
759 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
760 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
766 * gst_event_parse_gap:
767 * @event: a #GstEvent of type #GST_EVENT_GAP
768 * @timestamp: (out) (allow-none): location where to store the
769 * start time (pts) of the gap, or %NULL
770 * @duration: (out) (allow-none): location where to store the duration of
773 * Extract timestamp and duration from a new GAP event.
776 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
777 GstClockTime * duration)
779 GstStructure *structure;
781 g_return_if_fail (GST_IS_EVENT (event));
782 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
784 structure = GST_EVENT_STRUCTURE (event);
785 gst_structure_id_get (structure,
786 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
787 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
791 * gst_event_new_caps:
792 * @caps: (transfer none): a #GstCaps
794 * Create a new CAPS event for @caps. The caps event can only travel downstream
795 * synchronized with the buffer flow and contains the format of the buffers
796 * that will follow after the event.
798 * Returns: (transfer full): the new CAPS event.
801 gst_event_new_caps (GstCaps * caps)
805 g_return_val_if_fail (caps != NULL, NULL);
806 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
808 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
810 event = gst_event_new_custom (GST_EVENT_CAPS,
811 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
812 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
818 * gst_event_parse_caps:
819 * @event: The event to parse
820 * @caps: (out) (transfer none): A pointer to the caps
822 * Get the caps from @event. The caps remains valid as long as @event remains
826 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
828 GstStructure *structure;
830 g_return_if_fail (GST_IS_EVENT (event));
831 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
833 structure = GST_EVENT_STRUCTURE (event);
836 g_value_get_boxed (gst_structure_id_get_value (structure,
841 * gst_event_new_segment:
842 * @segment: (transfer none): a #GstSegment
844 * Create a new SEGMENT event for @segment. The segment event can only travel
845 * downstream synchronized with the buffer flow and contains timing information
846 * and playback properties for the buffers that will follow.
848 * The segment event marks the range of buffers to be processed. All
849 * data not within the segment range is not to be processed. This can be
850 * used intelligently by plugins to apply more efficient methods of skipping
851 * unneeded data. The valid range is expressed with the @start and @stop
854 * The time value of the segment is used in conjunction with the start
855 * value to convert the buffer timestamps into the stream time. This is
856 * usually done in sinks to report the current stream_time.
857 * @time represents the stream_time of a buffer carrying a timestamp of
858 * @start. @time cannot be -1.
860 * @start cannot be -1, @stop can be -1. If there
861 * is a valid @stop given, it must be greater or equal the @start, including
862 * when the indicated playback @rate is < 0.
864 * The @applied_rate value provides information about any rate adjustment that
865 * has already been made to the timestamps and content on the buffers of the
866 * stream. (@rate * @applied_rate) should always equal the rate that has been
867 * requested for playback. For example, if an element has an input segment
868 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
869 * incoming timestamps and buffer content by half and output a segment event
870 * with @rate of 1.0 and @applied_rate of 2.0
872 * After a segment event, the buffer stream time is calculated with:
874 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
876 * Returns: (transfer full): the new SEGMENT event.
879 gst_event_new_segment (const GstSegment * segment)
883 g_return_val_if_fail (segment != NULL, NULL);
884 g_return_val_if_fail (segment->rate != 0.0, NULL);
885 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
886 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
888 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
891 event = gst_event_new_custom (GST_EVENT_SEGMENT,
892 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
893 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
899 * gst_event_parse_segment:
900 * @event: The event to parse
901 * @segment: (out) (transfer none): a pointer to a #GstSegment
903 * Parses a segment @event and stores the result in the given @segment location.
904 * @segment remains valid only until the @event is freed. Don't modify the segment
905 * and make a copy if you want to modify it or store it for later use.
908 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
910 GstStructure *structure;
912 g_return_if_fail (GST_IS_EVENT (event));
913 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
916 structure = GST_EVENT_STRUCTURE (event);
917 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
918 GST_QUARK (SEGMENT)));
923 * gst_event_copy_segment:
924 * @event: The event to parse
925 * @segment: a pointer to a #GstSegment
927 * Parses a segment @event and copies the #GstSegment into the location
931 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
933 const GstSegment *src;
935 g_return_if_fail (GST_IS_EVENT (event));
936 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
939 gst_event_parse_segment (event, &src);
940 gst_segment_copy_into (src, segment);
946 * @taglist: (transfer full): metadata list. The event will take ownership
949 * Generates a metadata tag event from the given @taglist.
951 * The scope of the taglist specifies if the taglist applies to the
952 * complete medium or only to this specific stream. As the tag event
953 * is a sticky event, elements should merge tags received from
954 * upstream with a given scope with their own tags with the same
955 * scope and create a new tag event from it.
957 * Returns: (transfer full): a new #GstEvent
960 gst_event_new_tag (GstTagList * taglist)
963 GValue val = G_VALUE_INIT;
964 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
966 g_return_val_if_fail (taglist != NULL, NULL);
968 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
969 g_value_init (&val, GST_TYPE_TAG_LIST);
970 g_value_take_boxed (&val, taglist);
971 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
972 return gst_event_new_custom (GST_EVENT_TAG, s);
976 * gst_event_parse_tag:
977 * @event: a tag event
978 * @taglist: (out) (transfer none): pointer to metadata list
980 * Parses a tag @event and stores the results in the given @taglist location.
981 * No reference to the taglist will be returned, it remains valid only until
982 * the @event is freed. Don't modify or free the taglist, make a copy if you
983 * want to modify it or store it for later use.
986 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
990 g_return_if_fail (GST_IS_EVENT (event));
991 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
993 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
994 GST_QUARK (TAGLIST));
997 *taglist = (GstTagList *) g_value_get_boxed (val);
1000 /* buffersize event */
1002 * gst_event_new_buffer_size:
1003 * @format: buffer format
1004 * @minsize: minimum buffer size
1005 * @maxsize: maximum buffer size
1006 * @async: thread behavior
1008 * Create a new buffersize event. The event is sent downstream and notifies
1009 * elements that they should provide a buffer of the specified dimensions.
1011 * When the @async flag is set, a thread boundary is preferred.
1013 * Returns: (transfer full): a new #GstEvent
1016 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
1017 gint64 maxsize, gboolean async)
1020 GstStructure *structure;
1022 GST_CAT_INFO (GST_CAT_EVENT,
1023 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
1024 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
1025 minsize, maxsize, async);
1027 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
1028 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1029 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
1030 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
1031 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
1032 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
1038 * gst_event_parse_buffer_size:
1039 * @event: The event to query
1040 * @format: (out): A pointer to store the format in
1041 * @minsize: (out): A pointer to store the minsize in
1042 * @maxsize: (out): A pointer to store the maxsize in
1043 * @async: (out): A pointer to store the async-flag in
1045 * Get the format, minsize, maxsize and async-flag in the buffersize event.
1048 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
1049 gint64 * minsize, gint64 * maxsize, gboolean * async)
1051 const GstStructure *structure;
1053 g_return_if_fail (GST_IS_EVENT (event));
1054 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1056 structure = GST_EVENT_STRUCTURE (event);
1058 *format = (GstFormat)
1059 g_value_get_enum (gst_structure_id_get_value (structure,
1060 GST_QUARK (FORMAT)));
1063 g_value_get_int64 (gst_structure_id_get_value (structure,
1064 GST_QUARK (MINSIZE)));
1067 g_value_get_int64 (gst_structure_id_get_value (structure,
1068 GST_QUARK (MAXSIZE)));
1071 g_value_get_boolean (gst_structure_id_get_value (structure,
1072 GST_QUARK (ASYNC)));
1076 * gst_event_new_qos:
1077 * @type: the QoS type
1078 * @proportion: the proportion of the qos message
1079 * @diff: The time difference of the last Clock sync
1080 * @timestamp: The timestamp of the buffer
1082 * Allocate a new qos event with the given values.
1083 * The QOS event is generated in an element that wants an upstream
1084 * element to either reduce or increase its rate because of
1085 * high/low CPU load or other resource usage such as network performance or
1086 * throttling. Typically sinks generate these events for each buffer
1089 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1090 * used when a buffer arrived in time or when the sink cannot keep up with
1091 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1092 * receiving buffers fast enough and thus has to drop late buffers.
1093 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1094 * by the application, for example to reduce power consumption.
1096 * @proportion indicates the real-time performance of the streaming in the
1097 * element that generated the QoS event (usually the sink). The value is
1098 * generally computed based on more long term statistics about the streams
1099 * timestamps compared to the clock.
1100 * A value < 1.0 indicates that the upstream element is producing data faster
1101 * than real-time. A value > 1.0 indicates that the upstream element is not
1102 * producing data fast enough. 1.0 is the ideal @proportion value. The
1103 * proportion value can safely be used to lower or increase the quality of
1106 * @diff is the difference against the clock in running time of the last
1107 * buffer that caused the element to generate the QOS event. A negative value
1108 * means that the buffer with @timestamp arrived in time. A positive value
1109 * indicates how late the buffer with @timestamp was. When throttling is
1110 * enabled, @diff will be set to the requested throttling interval.
1112 * @timestamp is the timestamp of the last buffer that cause the element
1113 * to generate the QOS event. It is expressed in running time and thus an ever
1116 * The upstream element can use the @diff and @timestamp values to decide
1117 * whether to process more buffers. For positive @diff, all buffers with
1118 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1119 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1120 * result smaller than 0 is not allowed.
1122 * The application can use general event probes to intercept the QoS
1123 * event and implement custom application specific QoS handling.
1125 * Returns: (transfer full): a new QOS event.
1128 gst_event_new_qos (GstQOSType type, gdouble proportion,
1129 GstClockTimeDiff diff, GstClockTime timestamp)
1132 GstStructure *structure;
1134 /* diff must be positive or timestamp + diff must be positive */
1135 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1137 GST_CAT_LOG (GST_CAT_EVENT,
1138 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1139 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1140 diff, GST_TIME_ARGS (timestamp));
1142 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1143 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1144 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1145 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1146 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1147 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1153 * gst_event_parse_qos:
1154 * @event: The event to query
1155 * @type: (out): A pointer to store the QoS type in
1156 * @proportion: (out): A pointer to store the proportion in
1157 * @diff: (out): A pointer to store the diff in
1158 * @timestamp: (out): A pointer to store the timestamp in
1160 * Get the type, proportion, diff and timestamp in the qos event. See
1161 * gst_event_new_qos() for more information about the different QoS values.
1163 * @timestamp will be adjusted for any pad offsets of pads it was passing through.
1166 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1167 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1169 const GstStructure *structure;
1171 g_return_if_fail (GST_IS_EVENT (event));
1172 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1174 structure = GST_EVENT_STRUCTURE (event);
1176 *type = (GstQOSType)
1177 g_value_get_enum (gst_structure_id_get_value (structure,
1181 g_value_get_double (gst_structure_id_get_value (structure,
1182 GST_QUARK (PROPORTION)));
1185 g_value_get_int64 (gst_structure_id_get_value (structure,
1188 gint64 offset = gst_event_get_running_time_offset (event);
1189 GstClockTimeDiff diff_ =
1190 g_value_get_int64 (gst_structure_id_get_value (structure,
1194 g_value_get_uint64 (gst_structure_id_get_value (structure,
1195 GST_QUARK (TIMESTAMP)));
1196 /* Catch underflows */
1197 if (*timestamp > -offset)
1198 *timestamp += offset;
1202 /* Make sure that timestamp + diff is always >= 0. Because
1203 * of the running time offset this might not be true */
1204 if (diff_ < 0 && *timestamp < -diff_)
1205 *timestamp = (GstClockTime) - diff_;
1210 * gst_event_new_seek:
1211 * @rate: The new playback rate
1212 * @format: The format of the seek values
1213 * @flags: The optional seek flags
1214 * @start_type: The type and flags for the new start position
1215 * @start: The value of the new start position
1216 * @stop_type: The type and flags for the new stop position
1217 * @stop: The value of the new stop position
1219 * Allocate a new seek event with the given parameters.
1221 * The seek event configures playback of the pipeline between @start to @stop
1222 * at the speed given in @rate, also called a playback segment.
1223 * The @start and @stop values are expressed in @format.
1225 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1226 * Negatives values means backwards playback. A value of 0.0 for the
1227 * rate is not allowed and should be accomplished instead by PAUSING the
1230 * A pipeline has a default playback segment configured with a start
1231 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1232 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1234 * @start_type and @stop_type specify how to adjust the currently configured
1235 * start and stop fields in playback segment. Adjustments can be made relative
1236 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1237 * means that the position should not be updated.
1239 * When the rate is positive and @start has been updated, playback will start
1240 * from the newly configured start position.
1242 * For negative rates, playback will start from the newly configured stop
1243 * position (if any). If the stop position is updated, it must be different from
1244 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1246 * It is not possible to seek relative to the current playback position, to do
1247 * this, PAUSE the pipeline, query the current playback position with
1248 * #GST_QUERY_POSITION and update the playback segment current position with a
1249 * #GST_SEEK_TYPE_SET to the desired position.
1251 * Returns: (transfer full): a new seek event.
1254 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1255 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1258 GstStructure *structure;
1260 g_return_val_if_fail (rate != 0.0, NULL);
1262 if (format == GST_FORMAT_TIME) {
1263 GST_CAT_INFO (GST_CAT_EVENT,
1264 "creating seek rate %lf, format TIME, flags %d, "
1265 "start_type %d, start %" GST_TIME_FORMAT ", "
1266 "stop_type %d, stop %" GST_TIME_FORMAT,
1267 rate, flags, start_type, GST_TIME_ARGS (start),
1268 stop_type, GST_TIME_ARGS (stop));
1270 GST_CAT_INFO (GST_CAT_EVENT,
1271 "creating seek rate %lf, format %s, flags %d, "
1272 "start_type %d, start %" G_GINT64_FORMAT ", "
1273 "stop_type %d, stop %" G_GINT64_FORMAT,
1274 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1278 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1279 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1280 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1281 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1282 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1283 GST_QUARK (CUR), G_TYPE_INT64, start,
1284 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1285 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1286 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1292 * gst_event_parse_seek:
1293 * @event: a seek event
1294 * @rate: (out): result location for the rate
1295 * @format: (out): result location for the stream format
1296 * @flags: (out): result location for the #GstSeekFlags
1297 * @start_type: (out): result location for the #GstSeekType of the start position
1298 * @start: (out): result location for the start position expressed in @format
1299 * @stop_type: (out): result location for the #GstSeekType of the stop position
1300 * @stop: (out): result location for the stop position expressed in @format
1302 * Parses a seek @event and stores the results in the given result locations.
1305 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1306 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1307 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1309 const GstStructure *structure;
1311 g_return_if_fail (GST_IS_EVENT (event));
1312 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1314 structure = GST_EVENT_STRUCTURE (event);
1317 g_value_get_double (gst_structure_id_get_value (structure,
1320 *format = (GstFormat)
1321 g_value_get_enum (gst_structure_id_get_value (structure,
1322 GST_QUARK (FORMAT)));
1324 *flags = (GstSeekFlags)
1325 g_value_get_flags (gst_structure_id_get_value (structure,
1326 GST_QUARK (FLAGS)));
1328 *start_type = (GstSeekType)
1329 g_value_get_enum (gst_structure_id_get_value (structure,
1330 GST_QUARK (CUR_TYPE)));
1333 g_value_get_int64 (gst_structure_id_get_value (structure,
1336 *stop_type = (GstSeekType)
1337 g_value_get_enum (gst_structure_id_get_value (structure,
1338 GST_QUARK (STOP_TYPE)));
1341 g_value_get_int64 (gst_structure_id_get_value (structure,
1346 * gst_event_new_navigation:
1347 * @structure: (transfer full): description of the event. The event will take
1348 * ownership of the structure.
1350 * Create a new navigation event from the given description.
1352 * Returns: (transfer full): a new #GstEvent
1355 gst_event_new_navigation (GstStructure * structure)
1357 g_return_val_if_fail (structure != NULL, NULL);
1359 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1363 * gst_event_new_latency:
1364 * @latency: the new latency value
1366 * Create a new latency event. The event is sent upstream from the sinks and
1367 * notifies elements that they should add an additional @latency to the
1368 * running time before synchronising against the clock.
1370 * The latency is mostly used in live sinks and is always expressed in
1373 * Returns: (transfer full): a new #GstEvent
1376 gst_event_new_latency (GstClockTime latency)
1379 GstStructure *structure;
1381 GST_CAT_INFO (GST_CAT_EVENT,
1382 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1384 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1385 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1386 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1392 * gst_event_parse_latency:
1393 * @event: The event to query
1394 * @latency: (out): A pointer to store the latency in.
1396 * Get the latency in the latency event.
1399 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1401 g_return_if_fail (GST_IS_EVENT (event));
1402 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1406 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1407 (event), GST_QUARK (LATENCY)));
1411 * gst_event_new_step:
1412 * @format: the format of @amount
1413 * @amount: the amount of data to step
1414 * @rate: the step rate
1415 * @flush: flushing steps
1416 * @intermediate: intermediate steps
1418 * Create a new step event. The purpose of the step event is to instruct a sink
1419 * to skip @amount (expressed in @format) of media. It can be used to implement
1420 * stepping through the video frame by frame or for doing fast trick modes.
1422 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1423 * = 0.0 or first reverse the direction of playback using a seek event to get
1424 * the same effect as rate < 0.0.
1426 * The @flush flag will clear any pending data in the pipeline before starting
1427 * the step operation.
1429 * The @intermediate flag instructs the pipeline that this step operation is
1430 * part of a larger step operation.
1432 * Returns: (transfer full): a new #GstEvent
1435 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1436 gboolean flush, gboolean intermediate)
1439 GstStructure *structure;
1441 g_return_val_if_fail (rate > 0.0, NULL);
1443 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1445 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1446 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1447 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1448 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1449 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1450 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1451 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1457 * gst_event_parse_step:
1458 * @event: The event to query
1459 * @format: (out) (allow-none): a pointer to store the format in
1460 * @amount: (out) (allow-none): a pointer to store the amount in
1461 * @rate: (out) (allow-none): a pointer to store the rate in
1462 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1463 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1466 * Parse the step event.
1469 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1470 gdouble * rate, gboolean * flush, gboolean * intermediate)
1472 const GstStructure *structure;
1474 g_return_if_fail (GST_IS_EVENT (event));
1475 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1477 structure = GST_EVENT_STRUCTURE (event);
1480 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1481 GST_QUARK (FORMAT)));
1483 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1484 GST_QUARK (AMOUNT)));
1486 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1489 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1490 GST_QUARK (FLUSH)));
1492 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1493 GST_QUARK (INTERMEDIATE)));
1497 * gst_event_new_reconfigure:
1499 * Create a new reconfigure event. The purpose of the reconfigure event is
1500 * to travel upstream and make elements renegotiate their caps or reconfigure
1501 * their buffer pools. This is useful when changing properties on elements
1502 * or changing the topology of the pipeline.
1504 * Returns: (transfer full): a new #GstEvent
1507 gst_event_new_reconfigure (void)
1511 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1513 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1519 * gst_event_new_sink_message:
1520 * @name: a name for the event
1521 * @msg: (transfer none): the #GstMessage to be posted
1523 * Create a new sink-message event. The purpose of the sink-message event is
1524 * to instruct a sink to post the message contained in the event synchronized
1527 * @name is used to store multiple sticky events on one pad.
1529 * Returns: (transfer full): a new #GstEvent
1531 /* FIXME 2.0: take ownership of msg for consistency? */
1533 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1536 GstStructure *structure;
1538 g_return_val_if_fail (msg != NULL, NULL);
1540 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1542 structure = gst_structure_new_id (g_quark_from_string (name),
1543 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1544 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1550 * gst_event_parse_sink_message:
1551 * @event: The event to query
1552 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1554 * Parse the sink-message event. Unref @msg after usage.
1557 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1559 const GstStructure *structure;
1561 g_return_if_fail (GST_IS_EVENT (event));
1562 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1564 structure = GST_EVENT_STRUCTURE (event);
1567 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1568 (structure, GST_QUARK (MESSAGE))));
1572 * gst_event_new_stream_start:
1573 * @stream_id: Identifier for this stream
1575 * Create a new STREAM_START event. The stream start event can only
1576 * travel downstream synchronized with the buffer flow. It is expected
1577 * to be the first event that is sent for a new stream.
1579 * Source elements, demuxers and other elements that create new streams
1580 * are supposed to send this event as the first event of a new stream. It
1581 * should not be sent after a flushing seek or in similar situations
1582 * and is used to mark the beginning of a new logical stream. Elements
1583 * combining multiple streams must ensure that this event is only forwarded
1584 * downstream once and not for every single input stream.
1586 * The @stream_id should be a unique string that consists of the upstream
1587 * stream-id, / as separator and a unique stream-id for this specific
1588 * stream. A new stream-id should only be created for a stream if the upstream
1589 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1590 * but not for every single element in the pipeline.
1591 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1592 * used to create a stream-id. There are no particular semantics for the
1593 * stream-id, though it should be deterministic (to support stream matching)
1594 * and it might be used to order streams (besides any information conveyed by
1597 * Returns: (transfer full): the new STREAM_START event.
1600 gst_event_new_stream_start (const gchar * stream_id)
1604 g_return_val_if_fail (stream_id != NULL, NULL);
1606 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1607 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1608 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1610 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1614 * gst_event_parse_stream_start:
1615 * @event: a stream-start event.
1616 * @stream_id: (out) (transfer none): pointer to store the stream-id
1618 * Parse a stream-id @event and store the result in the given @stream_id
1619 * location. The string stored in @stream_id must not be modified and will
1620 * remain valid only until @event gets freed. Make a copy if you want to
1621 * modify it or store it for later use.
1624 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1626 const GstStructure *structure;
1629 g_return_if_fail (event != NULL);
1630 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1632 structure = gst_event_get_structure (event);
1633 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1636 *stream_id = g_value_get_string (val);
1640 * gst_event_set_stream:
1641 * @event: a stream-start event
1642 * @stream: (transfer none): the stream object to set
1644 * Set the @stream on the stream-start @event
1649 gst_event_set_stream (GstEvent * event, GstStream * stream)
1651 g_return_if_fail (event != NULL);
1652 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1653 g_return_if_fail (gst_event_is_writable (event));
1655 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1656 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1660 * gst_event_parse_stream:
1661 * @event: a stream-start event
1662 * @stream: (out) (transfer full): adress of variable to store the stream
1664 * Parse a stream-start @event and extract the #GstStream from it.
1669 gst_event_parse_stream (GstEvent * event, GstStream ** stream)
1671 g_return_if_fail (event != NULL);
1672 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1675 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1676 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1682 * gst_event_set_stream_flags:
1683 * @event: a stream-start event
1684 * @flags: the stream flags to set
1689 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1691 g_return_if_fail (event != NULL);
1692 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1693 g_return_if_fail (gst_event_is_writable (event));
1695 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1696 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1700 * gst_event_parse_stream_flags:
1701 * @event: a stream-start event
1702 * @flags: (out): address of variable where to store the stream flags
1707 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1709 g_return_if_fail (event != NULL);
1710 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1713 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1714 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1719 * gst_event_set_group_id:
1720 * @event: a stream-start event
1721 * @group_id: the group id to set
1723 * All streams that have the same group id are supposed to be played
1724 * together, i.e. all streams inside a container file should have the
1725 * same group id but different stream ids. The group id should change
1726 * each time the stream is started, resulting in different group ids
1727 * each time a file is played for example.
1729 * Use gst_util_group_id_next() to get a new group id.
1734 gst_event_set_group_id (GstEvent * event, guint group_id)
1736 g_return_if_fail (event != NULL);
1737 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1738 g_return_if_fail (gst_event_is_writable (event));
1740 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1741 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1745 * gst_event_parse_group_id:
1746 * @event: a stream-start event
1747 * @group_id: (out): address of variable where to store the group id
1749 * Returns: %TRUE if a group id was set on the event and could be parsed,
1755 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1757 g_return_val_if_fail (event != NULL, FALSE);
1758 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1762 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1763 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1770 * gst_event_new_stream_collection:
1771 * @collection: Active collection for this data flow
1773 * Create a new STREAM_COLLECTION event. The stream collection event can only
1774 * travel downstream synchronized with the buffer flow.
1776 * Source elements, demuxers and other elements that manage collections
1777 * of streams and post #GstStreamCollection messages on the bus also send
1778 * this event downstream on each pad involved in the collection, so that
1779 * activation of a new collection can be tracked through the downstream
1782 * Returns: (transfer full): the new STREAM_COLLECTION event.
1787 gst_event_new_stream_collection (GstStreamCollection * collection)
1791 g_return_val_if_fail (collection != NULL, NULL);
1792 g_return_val_if_fail (GST_IS_STREAM_COLLECTION (collection), NULL);
1794 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_COLLECTION),
1795 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1797 return gst_event_new_custom (GST_EVENT_STREAM_COLLECTION, s);
1801 * gst_event_parse_stream_collection:
1802 * @event: a stream-collection event
1803 * @collection: (out): pointer to store the collection
1805 * Retrieve new #GstStreamCollection from STREAM_COLLECTION event @event.
1810 gst_event_parse_stream_collection (GstEvent * event,
1811 GstStreamCollection ** collection)
1813 const GstStructure *structure;
1815 g_return_if_fail (event != NULL);
1816 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_COLLECTION);
1818 structure = gst_event_get_structure (event);
1821 gst_structure_id_get (structure,
1822 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1827 * gst_event_new_toc:
1828 * @toc: (transfer none): #GstToc structure.
1829 * @updated: whether @toc was updated or not.
1831 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1832 * inform elements that some kind of the TOC was found.
1834 * Returns: (transfer full): a new #GstEvent.
1837 gst_event_new_toc (GstToc * toc, gboolean updated)
1839 GstStructure *toc_struct;
1842 g_return_val_if_fail (toc != NULL, NULL);
1844 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1846 /* need different structure names so sticky_multi event stuff on pads
1847 * works, i.e. both TOC events are kept around */
1848 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1849 id = GST_QUARK (EVENT_TOC_GLOBAL);
1851 id = GST_QUARK (EVENT_TOC_CURRENT);
1853 toc_struct = gst_structure_new_id (id,
1854 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1855 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1857 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1861 * gst_event_parse_toc:
1862 * @event: a TOC event.
1863 * @toc: (out) (transfer full): pointer to #GstToc structure.
1864 * @updated: (out): pointer to store TOC updated flag.
1866 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1869 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1871 const GstStructure *structure;
1873 g_return_if_fail (event != NULL);
1874 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1875 g_return_if_fail (toc != NULL);
1877 structure = gst_event_get_structure (event);
1879 gst_structure_id_get (structure,
1880 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1881 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1885 * gst_event_new_toc_select:
1886 * @uid: UID in the TOC to start playback from.
1888 * Generate a TOC select event with the given @uid. The purpose of the
1889 * TOC select event is to start playback based on the TOC's entry with the
1892 * Returns: a new #GstEvent.
1895 gst_event_new_toc_select (const gchar * uid)
1897 GstStructure *structure;
1899 g_return_val_if_fail (uid != NULL, NULL);
1901 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1903 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1904 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1906 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1910 * gst_event_parse_toc_select:
1911 * @event: a TOC select event.
1912 * @uid: (out) (transfer full) (allow-none): storage for the selection UID.
1914 * Parse a TOC select @event and store the results in the given @uid location.
1917 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1919 const GstStructure *structure;
1922 g_return_if_fail (event != NULL);
1923 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1925 structure = gst_event_get_structure (event);
1926 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1929 *uid = g_strdup (g_value_get_string (val));
1934 * gst_event_new_protection:
1935 * @system_id: (transfer none): a string holding a UUID that uniquely
1936 * identifies a protection system.
1937 * @data: (transfer none): a #GstBuffer holding protection system specific
1938 * information. The reference count of the buffer will be incremented by one.
1939 * @origin: a string indicating where the protection
1940 * information carried in the event was extracted from. The allowed values
1941 * of this string will depend upon the protection scheme.
1943 * Creates a new event containing information specific to a particular
1944 * protection system (uniquely identified by @system_id), by which that
1945 * protection system can acquire key(s) to decrypt a protected stream.
1947 * In order for a decryption element to decrypt media
1948 * protected using a specific system, it first needs all the
1949 * protection system specific information necessary to acquire the decryption
1950 * key(s) for that stream. The functions defined here enable this information
1951 * to be passed in events from elements that extract it
1952 * (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter
1953 * elements that use it.
1955 * Events containing protection system specific information are created using
1956 * #gst_event_new_protection, and they can be parsed by downstream elements
1957 * using #gst_event_parse_protection.
1959 * In Common Encryption, protection system specific information may be located
1960 * within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof)
1961 * boxes; it may also be contained in ContentProtection elements within MPEG
1962 * DASH MPDs. The events created by #gst_event_new_protection contain data
1963 * identifying from which of these locations the encapsulated protection system
1964 * specific information originated. This origin information is required as
1965 * some protection systems use different encodings depending upon where the
1966 * information originates.
1968 * The events returned by gst_event_new_protection() are implemented
1969 * in such a way as to ensure that the most recently-pushed protection info
1970 * event of a particular @origin and @system_id will
1971 * be stuck to the output pad of the sending element.
1973 * Returns: a #GST_EVENT_PROTECTION event, if successful; %NULL
1979 gst_event_new_protection (const gchar * system_id,
1980 GstBuffer * data, const gchar * origin)
1986 g_return_val_if_fail (system_id != NULL, NULL);
1987 g_return_val_if_fail (data != NULL, NULL);
1990 g_strconcat ("GstProtectionEvent", origin ? "-" : "",
1991 origin ? origin : "", "-", system_id, NULL);
1993 GST_CAT_INFO (GST_CAT_EVENT, "creating protection event %s", event_name);
1995 s = gst_structure_new (event_name, "data", GST_TYPE_BUFFER, data,
1996 "system_id", G_TYPE_STRING, system_id, NULL);
1998 gst_structure_set (s, "origin", G_TYPE_STRING, origin, NULL);
1999 event = gst_event_new_custom (GST_EVENT_PROTECTION, s);
2001 g_free (event_name);
2006 * gst_event_parse_protection:
2007 * @event: a #GST_EVENT_PROTECTION event.
2008 * @system_id: (out) (allow-none) (transfer none): pointer to store the UUID
2009 * string uniquely identifying a content protection system.
2010 * @data: (out) (allow-none) (transfer none): pointer to store a #GstBuffer
2011 * holding protection system specific information.
2012 * @origin: (allow-none) (transfer none): pointer to store a value that
2013 * indicates where the protection information carried by @event was extracted
2016 * Parses an event containing protection system specific information and stores
2017 * the results in @system_id, @data and @origin. The data stored in @system_id,
2018 * @origin and @data are valid until @event is released.
2023 gst_event_parse_protection (GstEvent * event, const gchar ** system_id,
2024 GstBuffer ** data, const gchar ** origin)
2026 const GstStructure *s;
2028 g_return_if_fail (event != NULL);
2029 g_return_if_fail (GST_IS_EVENT (event));
2030 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_PROTECTION);
2032 s = gst_event_get_structure (event);
2035 *origin = gst_structure_get_string (s, "origin");
2038 *system_id = gst_structure_get_string (s, "system_id");
2041 const GValue *value = gst_structure_get_value (s, "data");
2042 *data = gst_value_get_buffer (value);
2047 * gst_event_new_segment_done:
2048 * @format: The format of the position being done
2049 * @position: The position of the segment being done
2051 * Create a new segment-done event. This event is sent by elements that
2052 * finish playback of a segment as a result of a segment seek.
2054 * Returns: (transfer full): a new #GstEvent
2057 gst_event_new_segment_done (GstFormat format, gint64 position)
2060 GstStructure *structure;
2062 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
2064 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
2065 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
2066 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
2068 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
2074 * gst_event_parse_segment_done:
2075 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
2076 * @format: (out) (allow-none): Result location for the format, or %NULL
2077 * @position: (out) (allow-none): Result location for the position, or %NULL
2079 * Extracts the position and format from the segment done message.
2083 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
2086 const GstStructure *structure;
2089 g_return_if_fail (event != NULL);
2090 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
2092 structure = gst_event_get_structure (event);
2094 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
2096 *format = g_value_get_enum (val);
2098 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
2099 if (position != NULL)
2100 *position = g_value_get_int64 (val);