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.
27 * @short_description: Structure describing events that are passed up and down
29 * @see_also: #GstPad, #GstElement
31 * The event class provides factory methods to construct events for sending
32 * and functions to query (parse) received events.
34 * Events are usually created with gst_event_new_*() which takes event-type
35 * specific parameters as arguments.
36 * To send an event application will usually use gst_element_send_event() and
37 * elements will use gst_pad_send_event() or gst_pad_push_event().
38 * The event should be unreffed with gst_event_unref() if it has not been sent.
40 * Events that have been received can be parsed with their respective
41 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
43 * Events are passed between elements in parallel to the data stream. Some events
44 * are serialized with buffers, others are not. Some events only travel downstream,
45 * others only upstream. Some events can travel both upstream and downstream.
47 * The events are used to signal special conditions in the datastream such as
48 * EOS (end of stream) or the start of a new stream-segment.
49 * Events are also used to flush the pipeline of any pending data.
51 * Most of the event API is used inside plugins. Applications usually only
52 * construct and use seek events.
53 * To do that gst_event_new_seek() is used to create a seek event. It takes
54 * the needed parameters to specify seeking time and mode.
55 * |[<!-- language="C" -->
59 * // construct a seek event to play the media from second 2 to 5, flush
60 * // the pipeline to decrease latency.
61 * event = gst_event_new_seek (1.0,
63 * GST_SEEK_FLAG_FLUSH,
64 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
65 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
67 * result = gst_element_send_event (pipeline, event);
69 * g_warning ("seek failed");
75 #include "gst_private.h"
76 #include <string.h> /* memcpy */
80 #include "gstenumtypes.h"
85 GType _gst_event_type = 0;
91 GstStructure *structure;
92 gint64 running_time_offset;
95 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
104 static GstEventQuarks event_quarks[] = {
105 {GST_EVENT_UNKNOWN, "unknown", 0},
106 {GST_EVENT_FLUSH_START, "flush-start", 0},
107 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
108 {GST_EVENT_SELECT_STREAMS, "select-streams", 0},
109 {GST_EVENT_STREAM_START, "stream-start", 0},
110 {GST_EVENT_STREAM_COLLECTION, "stream-collection", 0},
111 {GST_EVENT_CAPS, "caps", 0},
112 {GST_EVENT_SEGMENT, "segment", 0},
113 {GST_EVENT_TAG, "tag", 0},
114 {GST_EVENT_TOC, "toc", 0},
115 {GST_EVENT_PROTECTION, "protection", 0},
116 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
117 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
118 {GST_EVENT_EOS, "eos", 0},
119 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
120 {GST_EVENT_GAP, "gap", 0},
121 {GST_EVENT_QOS, "qos", 0},
122 {GST_EVENT_SEEK, "seek", 0},
123 {GST_EVENT_NAVIGATION, "navigation", 0},
124 {GST_EVENT_LATENCY, "latency", 0},
125 {GST_EVENT_STEP, "step", 0},
126 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
127 {GST_EVENT_TOC_SELECT, "toc-select", 0},
128 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
129 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
130 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
131 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
132 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
133 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
134 {GST_EVENT_STREAM_GROUP_DONE, "stream-group-done", 0},
139 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
142 _priv_gst_event_initialize (void)
146 _gst_event_type = gst_event_get_type ();
148 g_type_class_ref (gst_seek_flags_get_type ());
149 g_type_class_ref (gst_seek_type_get_type ());
151 for (i = 0; event_quarks[i].name; i++) {
152 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
157 * gst_event_type_get_name:
158 * @type: the event type
160 * Get a printable name for the given event type. Do not modify or free.
162 * Returns: a reference to the static name of the event.
165 gst_event_type_get_name (GstEventType type)
169 for (i = 0; event_quarks[i].name; i++) {
170 if (type == event_quarks[i].type)
171 return event_quarks[i].name;
177 * gst_event_type_to_quark:
178 * @type: the event type
180 * Get the unique quark for the given event type.
182 * Returns: the quark associated with the event type
185 gst_event_type_to_quark (GstEventType type)
189 for (i = 0; event_quarks[i].name; i++) {
190 if (type == event_quarks[i].type)
191 return event_quarks[i].quark;
197 * gst_event_type_get_flags:
198 * @type: a #GstEventType
200 * Gets the #GstEventTypeFlags associated with @type.
202 * Returns: a #GstEventTypeFlags.
205 gst_event_type_get_flags (GstEventType type)
207 GstEventTypeFlags ret;
209 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
215 _gst_event_free (GstEvent * event)
219 g_return_if_fail (event != NULL);
220 g_return_if_fail (GST_IS_EVENT (event));
222 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
223 GST_EVENT_TYPE_NAME (event));
225 s = GST_EVENT_STRUCTURE (event);
228 gst_structure_set_parent_refcount (s, NULL);
229 gst_structure_free (s);
232 g_slice_free1 (sizeof (GstEventImpl), event);
235 static void gst_event_init (GstEventImpl * event, GstEventType type);
238 _gst_event_copy (GstEvent * event)
243 copy = g_slice_new0 (GstEventImpl);
245 gst_event_init (copy, GST_EVENT_TYPE (event));
247 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
248 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
250 s = GST_EVENT_STRUCTURE (event);
252 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
253 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
254 ©->event.mini_object.refcount);
256 GST_EVENT_STRUCTURE (copy) = NULL;
259 ((GstEventImpl *) copy)->running_time_offset =
260 ((GstEventImpl *) event)->running_time_offset;
262 return GST_EVENT_CAST (copy);
266 gst_event_init (GstEventImpl * event, GstEventType type)
268 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
269 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
270 (GstMiniObjectFreeFunction) _gst_event_free);
272 GST_EVENT_TYPE (event) = type;
273 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
274 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
275 event->running_time_offset = 0;
280 * gst_event_new_custom:
281 * @type: The type of the new event
282 * @structure: (transfer full): the structure for the event. The event will
283 * take ownership of the structure.
285 * Create a new custom-typed event. This can be used for anything not
286 * handled by other event-specific functions to pass an event to another
289 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
290 * assigning a free number and filling in the correct direction and
291 * serialization flags.
293 * New custom events can also be created by subclassing the event type if
296 * Returns: (transfer full) (nullable): the new custom event.
299 gst_event_new_custom (GstEventType type, GstStructure * structure)
303 event = g_slice_new0 (GstEventImpl);
305 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
306 gst_event_type_get_name (type), type);
309 /* structure must not have a parent */
310 if (!gst_structure_set_parent_refcount (structure,
311 &event->event.mini_object.refcount))
315 gst_event_init (event, type);
317 GST_EVENT_STRUCTURE (event) = structure;
319 return GST_EVENT_CAST (event);
324 g_slice_free1 (sizeof (GstEventImpl), event);
325 g_warning ("structure is already owned by another object");
331 * gst_event_get_structure:
332 * @event: The #GstEvent.
334 * Access the structure of the event.
336 * Returns: (transfer none) (nullable): The structure of the event. The
337 * structure is still owned by the event, which means that you should not free
338 * it and that the pointer becomes invalid when you free the event.
343 gst_event_get_structure (GstEvent * event)
345 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
347 return GST_EVENT_STRUCTURE (event);
351 * gst_event_writable_structure:
352 * @event: The #GstEvent.
354 * Get a writable version of the structure.
356 * Returns: (transfer none): The structure of the event. The structure
357 * is still owned by the event, which means that you should not free
358 * it and that the pointer becomes invalid when you free the event.
359 * This function checks if @event is writable and will never return
365 gst_event_writable_structure (GstEvent * event)
367 GstStructure *structure;
369 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
370 g_return_val_if_fail (gst_event_is_writable (event), NULL);
372 structure = GST_EVENT_STRUCTURE (event);
374 if (structure == NULL) {
376 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
378 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
379 GST_EVENT_STRUCTURE (event) = structure;
385 * gst_event_has_name:
386 * @event: The #GstEvent.
387 * @name: name to check
389 * Checks if @event has the given @name. This function is usually used to
390 * check the name of a custom event.
392 * Returns: %TRUE if @name matches the name of the event structure.
395 gst_event_has_name (GstEvent * event, const gchar * name)
397 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
399 if (GST_EVENT_STRUCTURE (event) == NULL)
402 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
406 * gst_event_get_seqnum:
407 * @event: A #GstEvent.
409 * Retrieve the sequence number of a event.
411 * Events have ever-incrementing sequence numbers, which may also be set
412 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
413 * indicate that a event corresponds to some other set of events or messages,
414 * for example an EOS event corresponding to a SEEK event. It is considered good
415 * practice to make this correspondence when possible, though it is not
418 * Note that events and messages share the same sequence number incrementor;
419 * two events or messages will never have the same sequence number unless
420 * that correspondence was made explicitly.
422 * Returns: The event's sequence number.
427 gst_event_get_seqnum (GstEvent * event)
429 g_return_val_if_fail (GST_IS_EVENT (event), -1);
431 return GST_EVENT_SEQNUM (event);
435 * gst_event_set_seqnum:
436 * @event: A #GstEvent.
437 * @seqnum: A sequence number.
439 * Set the sequence number of a event.
441 * This function might be called by the creator of a event to indicate that the
442 * event relates to other events or messages. See gst_event_get_seqnum() for
448 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
450 g_return_if_fail (GST_IS_EVENT (event));
451 g_return_if_fail (seqnum != GST_SEQNUM_INVALID);
453 GST_EVENT_SEQNUM (event) = seqnum;
457 * gst_event_get_running_time_offset:
458 * @event: A #GstEvent.
460 * Retrieve the accumulated running time offset of the event.
462 * Events passing through #GstPads that have a running time
463 * offset set via gst_pad_set_offset() will get their offset
464 * adjusted according to the pad's offset.
466 * If the event contains any information that related to the
467 * running time, this information will need to be updated
468 * before usage with this offset.
470 * Returns: The event's running time offset
477 gst_event_get_running_time_offset (GstEvent * event)
479 g_return_val_if_fail (GST_IS_EVENT (event), 0);
481 return ((GstEventImpl *) event)->running_time_offset;
485 * gst_event_set_running_time_offset:
486 * @event: A #GstEvent.
487 * @offset: A the new running time offset
489 * Set the running time offset of a event. See
490 * gst_event_get_running_time_offset() for more information.
497 gst_event_set_running_time_offset (GstEvent * event, gint64 offset)
499 g_return_if_fail (GST_IS_EVENT (event));
501 ((GstEventImpl *) event)->running_time_offset = offset;
505 * gst_event_new_flush_start:
507 * Allocate a new flush start event. The flush start event can be sent
508 * upstream and downstream and travels out-of-bounds with the dataflow.
510 * It marks pads as being flushing and will make them return
511 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
512 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
513 * Any event (except a #GST_EVENT_FLUSH_STOP) received
514 * on a flushing pad will return %FALSE immediately.
516 * Elements should unlock any blocking functions and exit their streaming
517 * functions as fast as possible when this event is received.
519 * This event is typically generated after a seek to flush out all queued data
520 * in the pipeline so that the new media is played as soon as possible.
522 * Returns: (transfer full): a new flush start event.
525 gst_event_new_flush_start (void)
527 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
531 * gst_event_new_flush_stop:
532 * @reset_time: if time should be reset
534 * Allocate a new flush stop event. The flush stop event can be sent
535 * upstream and downstream and travels serialized with the dataflow.
536 * It is typically sent after sending a FLUSH_START event to make the
537 * pads accept data again.
539 * Elements can process this event synchronized with the dataflow since
540 * the preceding FLUSH_START event stopped the dataflow.
542 * This event is typically generated to complete a seek and to resume
545 * Returns: (transfer full): a new flush stop event.
548 gst_event_new_flush_stop (gboolean reset_time)
552 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
554 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
555 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
556 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
562 * gst_event_parse_flush_stop:
563 * @event: The event to parse
564 * @reset_time: (out): if time should be reset
566 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
569 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
571 GstStructure *structure;
573 g_return_if_fail (GST_IS_EVENT (event));
574 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
576 structure = GST_EVENT_STRUCTURE (event);
577 if (G_LIKELY (reset_time))
579 g_value_get_boolean (gst_structure_id_get_value (structure,
580 GST_QUARK (RESET_TIME)));
584 * gst_event_new_select_streams:
585 * @streams: (element-type utf8) (transfer none): the list of streams to
588 * Allocate a new select-streams event.
590 * The select-streams event requests the specified @streams to be activated.
592 * The list of @streams corresponds to the "Stream ID" of each stream to be
593 * activated. Those ID can be obtained via the #GstStream objects present
594 * in #GST_EVENT_STREAM_START, #GST_EVENT_STREAM_COLLECTION or
595 * #GST_MESSAGE_STREAM_COLLECTION.
597 * Note: The list of @streams can not be empty.
599 * Returns: (transfer full): a new select-streams event or %NULL in case of
600 * an error (like an empty streams list).
605 gst_event_new_select_streams (GList * streams)
608 GValue val = G_VALUE_INIT;
612 g_return_val_if_fail (streams != NULL, NULL);
614 GST_CAT_INFO (GST_CAT_EVENT, "Creating new select-streams event");
615 struc = gst_structure_new_id_empty (GST_QUARK (EVENT_SELECT_STREAMS));
616 g_value_init (&val, GST_TYPE_LIST);
617 /* Fill struc with streams */
618 for (tmpl = streams; tmpl; tmpl = tmpl->next) {
619 GValue strval = G_VALUE_INIT;
620 const gchar *str = (const gchar *) tmpl->data;
621 g_value_init (&strval, G_TYPE_STRING);
622 g_value_set_string (&strval, str);
623 gst_value_list_append_and_take_value (&val, &strval);
625 gst_structure_id_take_value (struc, GST_QUARK (STREAMS), &val);
626 event = gst_event_new_custom (GST_EVENT_SELECT_STREAMS, struc);
632 * gst_event_parse_select_streams:
633 * @event: The event to parse
634 * @streams: (out) (element-type utf8) (transfer full): the streams
636 * Parse the SELECT_STREAMS event and retrieve the contained streams.
641 gst_event_parse_select_streams (GstEvent * event, GList ** streams)
643 GstStructure *structure;
646 g_return_if_fail (GST_IS_EVENT (event));
647 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SELECT_STREAMS);
649 structure = GST_EVENT_STRUCTURE (event);
650 if (G_LIKELY (streams)) {
651 const GValue *vlist =
652 gst_structure_id_get_value (structure, GST_QUARK (STREAMS));
653 guint i, sz = gst_value_list_get_size (vlist);
654 for (i = 0; i < sz; i++) {
655 const GValue *strv = gst_value_list_get_value (vlist, i);
656 res = g_list_append (res, g_value_dup_string (strv));
664 * gst_event_new_stream_group_done:
665 * @group_id: the group id of the stream group which is ending
667 * Create a new Stream Group Done event. The stream-group-done event can
668 * only travel downstream synchronized with the buffer flow. Elements
669 * that receive the event on a pad should handle it mostly like EOS,
670 * and emit any data or pending buffers that would depend on more data
671 * arriving and unblock, since there won't be any more data.
673 * This event is followed by EOS at some point in the future, and is
674 * generally used when switching pads - to unblock downstream so that
675 * new pads can be exposed before sending EOS on the existing pads.
677 * Returns: (transfer full): the new stream-group-done event.
682 gst_event_new_stream_group_done (guint group_id)
686 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_GROUP_DONE),
687 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
689 return gst_event_new_custom (GST_EVENT_STREAM_GROUP_DONE, s);
693 * gst_event_parse_stream_group_done:
694 * @event: a stream-group-done event.
695 * @group_id: (out): address of variable to store the group id into
697 * Parse a stream-group-done @event and store the result in the given
698 * @group_id location.
703 gst_event_parse_stream_group_done (GstEvent * event, guint * group_id)
705 g_return_if_fail (event != NULL);
706 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_GROUP_DONE);
709 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
710 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
717 * Create a new EOS event. The eos event can only travel downstream
718 * synchronized with the buffer flow. Elements that receive the EOS
719 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
720 * when data after the EOS event arrives.
722 * The EOS event will travel down to the sink elements in the pipeline
723 * which will then post the #GST_MESSAGE_EOS on the bus after they have
724 * finished playing any buffered data.
726 * When all sinks have posted an EOS message, an EOS message is
727 * forwarded to the application.
729 * The EOS event itself will not cause any state transitions of the pipeline.
731 * Returns: (transfer full): the new EOS event.
734 gst_event_new_eos (void)
736 return gst_event_new_custom (GST_EVENT_EOS, NULL);
741 * @timestamp: the start time (pts) of the gap
742 * @duration: the duration of the gap
744 * Create a new GAP event. A gap event can be thought of as conceptually
745 * equivalent to a buffer to signal that there is no data for a certain
746 * amount of time. This is useful to signal a gap to downstream elements
747 * which may wait for data, such as muxers or mixers or overlays, especially
748 * for sparse streams such as subtitle streams.
750 * Returns: (transfer full): the new GAP event.
753 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
757 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
759 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
760 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
761 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
762 GST_TIME_ARGS (duration));
764 event = gst_event_new_custom (GST_EVENT_GAP,
765 gst_structure_new_id (GST_QUARK (EVENT_GAP),
766 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
767 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
773 * gst_event_parse_gap:
774 * @event: a #GstEvent of type #GST_EVENT_GAP
775 * @timestamp: (out) (allow-none): location where to store the
776 * start time (pts) of the gap, or %NULL
777 * @duration: (out) (allow-none): location where to store the duration of
780 * Extract timestamp and duration from a new GAP event.
783 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
784 GstClockTime * duration)
786 GstStructure *structure;
788 g_return_if_fail (GST_IS_EVENT (event));
789 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
791 structure = GST_EVENT_STRUCTURE (event);
792 gst_structure_id_get (structure,
793 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
794 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
798 * gst_event_new_caps:
799 * @caps: (transfer none): a #GstCaps
801 * Create a new CAPS event for @caps. The caps event can only travel downstream
802 * synchronized with the buffer flow and contains the format of the buffers
803 * that will follow after the event.
805 * Returns: (transfer full) (nullable): the new CAPS event.
808 gst_event_new_caps (GstCaps * caps)
812 g_return_val_if_fail (caps != NULL, NULL);
813 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
815 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
817 event = gst_event_new_custom (GST_EVENT_CAPS,
818 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
819 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
825 * gst_event_parse_caps:
826 * @event: The event to parse
827 * @caps: (out) (transfer none): A pointer to the caps
829 * Get the caps from @event. The caps remains valid as long as @event remains
833 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
835 GstStructure *structure;
837 g_return_if_fail (GST_IS_EVENT (event));
838 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
840 structure = GST_EVENT_STRUCTURE (event);
843 g_value_get_boxed (gst_structure_id_get_value (structure,
848 * gst_event_new_segment:
849 * @segment: (transfer none): a #GstSegment
851 * Create a new SEGMENT event for @segment. The segment event can only travel
852 * downstream synchronized with the buffer flow and contains timing information
853 * and playback properties for the buffers that will follow.
855 * The segment event marks the range of buffers to be processed. All
856 * data not within the segment range is not to be processed. This can be
857 * used intelligently by plugins to apply more efficient methods of skipping
858 * unneeded data. The valid range is expressed with the @start and @stop
861 * The time value of the segment is used in conjunction with the start
862 * value to convert the buffer timestamps into the stream time. This is
863 * usually done in sinks to report the current stream_time.
864 * @time represents the stream_time of a buffer carrying a timestamp of
865 * @start. @time cannot be -1.
867 * @start cannot be -1, @stop can be -1. If there
868 * is a valid @stop given, it must be greater or equal the @start, including
869 * when the indicated playback @rate is < 0.
871 * The @applied_rate value provides information about any rate adjustment that
872 * has already been made to the timestamps and content on the buffers of the
873 * stream. (@rate * @applied_rate) should always equal the rate that has been
874 * requested for playback. For example, if an element has an input segment
875 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
876 * incoming timestamps and buffer content by half and output a segment event
877 * with @rate of 1.0 and @applied_rate of 2.0
879 * After a segment event, the buffer stream time is calculated with:
881 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
883 * Returns: (transfer full) (nullable): the new SEGMENT event.
886 gst_event_new_segment (const GstSegment * segment)
890 g_return_val_if_fail (segment != NULL, NULL);
891 g_return_val_if_fail (segment->rate != 0.0, NULL);
892 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
893 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
895 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
898 event = gst_event_new_custom (GST_EVENT_SEGMENT,
899 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
900 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
906 * gst_event_parse_segment:
907 * @event: The event to parse
908 * @segment: (out) (transfer none): a pointer to a #GstSegment
910 * Parses a segment @event and stores the result in the given @segment location.
911 * @segment remains valid only until the @event is freed. Don't modify the segment
912 * and make a copy if you want to modify it or store it for later use.
915 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
917 GstStructure *structure;
919 g_return_if_fail (GST_IS_EVENT (event));
920 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
923 structure = GST_EVENT_STRUCTURE (event);
924 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
925 GST_QUARK (SEGMENT)));
930 * gst_event_copy_segment:
931 * @event: The event to parse
932 * @segment: a pointer to a #GstSegment
934 * Parses a segment @event and copies the #GstSegment into the location
938 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
940 const GstSegment *src;
942 g_return_if_fail (GST_IS_EVENT (event));
943 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
946 gst_event_parse_segment (event, &src);
947 gst_segment_copy_into (src, segment);
953 * @taglist: (transfer full): metadata list. The event will take ownership
956 * Generates a metadata tag event from the given @taglist.
958 * The scope of the taglist specifies if the taglist applies to the
959 * complete medium or only to this specific stream. As the tag event
960 * is a sticky event, elements should merge tags received from
961 * upstream with a given scope with their own tags with the same
962 * scope and create a new tag event from it.
964 * Returns: (transfer full): a new #GstEvent
967 gst_event_new_tag (GstTagList * taglist)
970 GValue val = G_VALUE_INIT;
971 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
973 g_return_val_if_fail (taglist != NULL, NULL);
975 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
976 g_value_init (&val, GST_TYPE_TAG_LIST);
977 g_value_take_boxed (&val, taglist);
978 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
979 return gst_event_new_custom (GST_EVENT_TAG, s);
983 * gst_event_parse_tag:
984 * @event: a tag event
985 * @taglist: (out) (transfer none): pointer to metadata list
987 * Parses a tag @event and stores the results in the given @taglist location.
988 * No reference to the taglist will be returned, it remains valid only until
989 * the @event is freed. Don't modify or free the taglist, make a copy if you
990 * want to modify it or store it for later use.
993 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
997 g_return_if_fail (GST_IS_EVENT (event));
998 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
1000 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
1001 GST_QUARK (TAGLIST));
1004 *taglist = (GstTagList *) g_value_get_boxed (val);
1007 /* buffersize event */
1009 * gst_event_new_buffer_size:
1010 * @format: buffer format
1011 * @minsize: minimum buffer size
1012 * @maxsize: maximum buffer size
1013 * @async: thread behavior
1015 * Create a new buffersize event. The event is sent downstream and notifies
1016 * elements that they should provide a buffer of the specified dimensions.
1018 * When the @async flag is set, a thread boundary is preferred.
1020 * Returns: (transfer full): a new #GstEvent
1023 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
1024 gint64 maxsize, gboolean async)
1027 GstStructure *structure;
1029 GST_CAT_INFO (GST_CAT_EVENT,
1030 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
1031 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
1032 minsize, maxsize, async);
1034 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
1035 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1036 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
1037 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
1038 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
1039 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
1045 * gst_event_parse_buffer_size:
1046 * @event: The event to query
1047 * @format: (out): A pointer to store the format in
1048 * @minsize: (out): A pointer to store the minsize in
1049 * @maxsize: (out): A pointer to store the maxsize in
1050 * @async: (out): A pointer to store the async-flag in
1052 * Get the format, minsize, maxsize and async-flag in the buffersize event.
1055 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
1056 gint64 * minsize, gint64 * maxsize, gboolean * async)
1058 const GstStructure *structure;
1060 g_return_if_fail (GST_IS_EVENT (event));
1061 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1063 structure = GST_EVENT_STRUCTURE (event);
1065 *format = (GstFormat)
1066 g_value_get_enum (gst_structure_id_get_value (structure,
1067 GST_QUARK (FORMAT)));
1070 g_value_get_int64 (gst_structure_id_get_value (structure,
1071 GST_QUARK (MINSIZE)));
1074 g_value_get_int64 (gst_structure_id_get_value (structure,
1075 GST_QUARK (MAXSIZE)));
1078 g_value_get_boolean (gst_structure_id_get_value (structure,
1079 GST_QUARK (ASYNC)));
1083 * gst_event_new_qos:
1084 * @type: the QoS type
1085 * @proportion: the proportion of the qos message
1086 * @diff: The time difference of the last Clock sync
1087 * @timestamp: The timestamp of the buffer
1089 * Allocate a new qos event with the given values.
1090 * The QOS event is generated in an element that wants an upstream
1091 * element to either reduce or increase its rate because of
1092 * high/low CPU load or other resource usage such as network performance or
1093 * throttling. Typically sinks generate these events for each buffer
1096 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1097 * used when a buffer arrived in time or when the sink cannot keep up with
1098 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1099 * receiving buffers fast enough and thus has to drop late buffers.
1100 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1101 * by the application, for example to reduce power consumption.
1103 * @proportion indicates the real-time performance of the streaming in the
1104 * element that generated the QoS event (usually the sink). The value is
1105 * generally computed based on more long term statistics about the streams
1106 * timestamps compared to the clock.
1107 * A value < 1.0 indicates that the upstream element is producing data faster
1108 * than real-time. A value > 1.0 indicates that the upstream element is not
1109 * producing data fast enough. 1.0 is the ideal @proportion value. The
1110 * proportion value can safely be used to lower or increase the quality of
1113 * @diff is the difference against the clock in running time of the last
1114 * buffer that caused the element to generate the QOS event. A negative value
1115 * means that the buffer with @timestamp arrived in time. A positive value
1116 * indicates how late the buffer with @timestamp was. When throttling is
1117 * enabled, @diff will be set to the requested throttling interval.
1119 * @timestamp is the timestamp of the last buffer that cause the element
1120 * to generate the QOS event. It is expressed in running time and thus an ever
1123 * The upstream element can use the @diff and @timestamp values to decide
1124 * whether to process more buffers. For positive @diff, all buffers with
1125 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1126 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1127 * result smaller than 0 is not allowed.
1129 * The application can use general event probes to intercept the QoS
1130 * event and implement custom application specific QoS handling.
1132 * Returns: (transfer full) (nullable): a new QOS event.
1135 gst_event_new_qos (GstQOSType type, gdouble proportion,
1136 GstClockTimeDiff diff, GstClockTime timestamp)
1139 GstStructure *structure;
1141 /* diff must be positive or timestamp + diff must be positive */
1142 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1144 GST_CAT_LOG (GST_CAT_EVENT,
1145 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1146 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1147 diff, GST_TIME_ARGS (timestamp));
1149 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1150 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1151 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1152 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1153 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1154 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1160 * gst_event_parse_qos:
1161 * @event: The event to query
1162 * @type: (out): A pointer to store the QoS type in
1163 * @proportion: (out): A pointer to store the proportion in
1164 * @diff: (out): A pointer to store the diff in
1165 * @timestamp: (out): A pointer to store the timestamp in
1167 * Get the type, proportion, diff and timestamp in the qos event. See
1168 * gst_event_new_qos() for more information about the different QoS values.
1170 * @timestamp will be adjusted for any pad offsets of pads it was passing through.
1173 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1174 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1176 const GstStructure *structure;
1178 g_return_if_fail (GST_IS_EVENT (event));
1179 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1181 structure = GST_EVENT_STRUCTURE (event);
1183 *type = (GstQOSType)
1184 g_value_get_enum (gst_structure_id_get_value (structure,
1188 g_value_get_double (gst_structure_id_get_value (structure,
1189 GST_QUARK (PROPORTION)));
1192 g_value_get_int64 (gst_structure_id_get_value (structure,
1195 gint64 offset = gst_event_get_running_time_offset (event);
1196 GstClockTimeDiff diff_ =
1197 g_value_get_int64 (gst_structure_id_get_value (structure,
1201 g_value_get_uint64 (gst_structure_id_get_value (structure,
1202 GST_QUARK (TIMESTAMP)));
1203 /* Catch underflows */
1204 if (*timestamp > -offset)
1205 *timestamp += offset;
1209 /* Make sure that timestamp + diff is always >= 0. Because
1210 * of the running time offset this might not be true */
1211 if (diff_ < 0 && *timestamp < -diff_)
1212 *timestamp = (GstClockTime) - diff_;
1217 * gst_event_new_seek:
1218 * @rate: The new playback rate
1219 * @format: The format of the seek values
1220 * @flags: The optional seek flags
1221 * @start_type: The type and flags for the new start position
1222 * @start: The value of the new start position
1223 * @stop_type: The type and flags for the new stop position
1224 * @stop: The value of the new stop position
1226 * Allocate a new seek event with the given parameters.
1228 * The seek event configures playback of the pipeline between @start to @stop
1229 * at the speed given in @rate, also called a playback segment.
1230 * The @start and @stop values are expressed in @format.
1232 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1233 * Negatives values means backwards playback. A value of 0.0 for the
1234 * rate is not allowed and should be accomplished instead by PAUSING the
1237 * A pipeline has a default playback segment configured with a start
1238 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1239 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1241 * @start_type and @stop_type specify how to adjust the currently configured
1242 * start and stop fields in playback segment. Adjustments can be made relative
1243 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1244 * means that the position should not be updated.
1246 * When the rate is positive and @start has been updated, playback will start
1247 * from the newly configured start position.
1249 * For negative rates, playback will start from the newly configured stop
1250 * position (if any). If the stop position is updated, it must be different from
1251 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1253 * It is not possible to seek relative to the current playback position, to do
1254 * this, PAUSE the pipeline, query the current playback position with
1255 * #GST_QUERY_POSITION and update the playback segment current position with a
1256 * #GST_SEEK_TYPE_SET to the desired position.
1258 * Returns: (transfer full) (nullable): a new seek event.
1261 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1262 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1265 GstStructure *structure;
1267 g_return_val_if_fail (rate != 0.0, NULL);
1269 if (format == GST_FORMAT_TIME) {
1270 GST_CAT_INFO (GST_CAT_EVENT,
1271 "creating seek rate %lf, format TIME, flags %d, "
1272 "start_type %d, start %" GST_TIME_FORMAT ", "
1273 "stop_type %d, stop %" GST_TIME_FORMAT,
1274 rate, flags, start_type, GST_TIME_ARGS (start),
1275 stop_type, GST_TIME_ARGS (stop));
1277 GST_CAT_INFO (GST_CAT_EVENT,
1278 "creating seek rate %lf, format %s, flags %d, "
1279 "start_type %d, start %" G_GINT64_FORMAT ", "
1280 "stop_type %d, stop %" G_GINT64_FORMAT,
1281 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1285 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1286 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1287 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1288 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1289 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1290 GST_QUARK (CUR), G_TYPE_INT64, start,
1291 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1292 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1293 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1299 * gst_event_parse_seek:
1300 * @event: a seek event
1301 * @rate: (out): result location for the rate
1302 * @format: (out): result location for the stream format
1303 * @flags: (out): result location for the #GstSeekFlags
1304 * @start_type: (out): result location for the #GstSeekType of the start position
1305 * @start: (out): result location for the start position expressed in @format
1306 * @stop_type: (out): result location for the #GstSeekType of the stop position
1307 * @stop: (out): result location for the stop position expressed in @format
1309 * Parses a seek @event and stores the results in the given result locations.
1312 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1313 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1314 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1316 const GstStructure *structure;
1318 g_return_if_fail (GST_IS_EVENT (event));
1319 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1321 structure = GST_EVENT_STRUCTURE (event);
1324 g_value_get_double (gst_structure_id_get_value (structure,
1327 *format = (GstFormat)
1328 g_value_get_enum (gst_structure_id_get_value (structure,
1329 GST_QUARK (FORMAT)));
1331 *flags = (GstSeekFlags)
1332 g_value_get_flags (gst_structure_id_get_value (structure,
1333 GST_QUARK (FLAGS)));
1335 *start_type = (GstSeekType)
1336 g_value_get_enum (gst_structure_id_get_value (structure,
1337 GST_QUARK (CUR_TYPE)));
1340 g_value_get_int64 (gst_structure_id_get_value (structure,
1343 *stop_type = (GstSeekType)
1344 g_value_get_enum (gst_structure_id_get_value (structure,
1345 GST_QUARK (STOP_TYPE)));
1348 g_value_get_int64 (gst_structure_id_get_value (structure,
1353 * gst_event_new_navigation:
1354 * @structure: (transfer full): description of the event. The event will take
1355 * ownership of the structure.
1357 * Create a new navigation event from the given description.
1359 * Returns: (transfer full): a new #GstEvent
1362 gst_event_new_navigation (GstStructure * structure)
1364 g_return_val_if_fail (structure != NULL, NULL);
1366 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1370 * gst_event_new_latency:
1371 * @latency: the new latency value
1373 * Create a new latency event. The event is sent upstream from the sinks and
1374 * notifies elements that they should add an additional @latency to the
1375 * running time before synchronising against the clock.
1377 * The latency is mostly used in live sinks and is always expressed in
1380 * Returns: (transfer full): a new #GstEvent
1383 gst_event_new_latency (GstClockTime latency)
1386 GstStructure *structure;
1388 GST_CAT_INFO (GST_CAT_EVENT,
1389 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1391 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1392 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1393 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1399 * gst_event_parse_latency:
1400 * @event: The event to query
1401 * @latency: (out): A pointer to store the latency in.
1403 * Get the latency in the latency event.
1406 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1408 g_return_if_fail (GST_IS_EVENT (event));
1409 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1413 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1414 (event), GST_QUARK (LATENCY)));
1418 * gst_event_new_step:
1419 * @format: the format of @amount
1420 * @amount: the amount of data to step
1421 * @rate: the step rate
1422 * @flush: flushing steps
1423 * @intermediate: intermediate steps
1425 * Create a new step event. The purpose of the step event is to instruct a sink
1426 * to skip @amount (expressed in @format) of media. It can be used to implement
1427 * stepping through the video frame by frame or for doing fast trick modes.
1429 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1430 * = 0.0 or first reverse the direction of playback using a seek event to get
1431 * the same effect as rate < 0.0.
1433 * The @flush flag will clear any pending data in the pipeline before starting
1434 * the step operation.
1436 * The @intermediate flag instructs the pipeline that this step operation is
1437 * part of a larger step operation.
1439 * Returns: (transfer full) (nullable): a new #GstEvent
1442 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1443 gboolean flush, gboolean intermediate)
1446 GstStructure *structure;
1448 g_return_val_if_fail (rate > 0.0, NULL);
1450 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1452 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1453 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1454 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1455 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1456 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1457 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1458 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1464 * gst_event_parse_step:
1465 * @event: The event to query
1466 * @format: (out) (allow-none): a pointer to store the format in
1467 * @amount: (out) (allow-none): a pointer to store the amount in
1468 * @rate: (out) (allow-none): a pointer to store the rate in
1469 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1470 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1473 * Parse the step event.
1476 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1477 gdouble * rate, gboolean * flush, gboolean * intermediate)
1479 const GstStructure *structure;
1481 g_return_if_fail (GST_IS_EVENT (event));
1482 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1484 structure = GST_EVENT_STRUCTURE (event);
1487 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1488 GST_QUARK (FORMAT)));
1490 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1491 GST_QUARK (AMOUNT)));
1493 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1496 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1497 GST_QUARK (FLUSH)));
1499 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1500 GST_QUARK (INTERMEDIATE)));
1504 * gst_event_new_reconfigure:
1506 * Create a new reconfigure event. The purpose of the reconfigure event is
1507 * to travel upstream and make elements renegotiate their caps or reconfigure
1508 * their buffer pools. This is useful when changing properties on elements
1509 * or changing the topology of the pipeline.
1511 * Returns: (transfer full): a new #GstEvent
1514 gst_event_new_reconfigure (void)
1518 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1520 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1526 * gst_event_new_sink_message:
1527 * @name: a name for the event
1528 * @msg: (transfer none): the #GstMessage to be posted
1530 * Create a new sink-message event. The purpose of the sink-message event is
1531 * to instruct a sink to post the message contained in the event synchronized
1534 * @name is used to store multiple sticky events on one pad.
1536 * Returns: (transfer full): a new #GstEvent
1538 /* FIXME 2.0: take ownership of msg for consistency? */
1540 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1543 GstStructure *structure;
1545 g_return_val_if_fail (msg != NULL, NULL);
1547 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1549 structure = gst_structure_new_id (g_quark_from_string (name),
1550 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1551 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1557 * gst_event_parse_sink_message:
1558 * @event: The event to query
1559 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1561 * Parse the sink-message event. Unref @msg after usage.
1564 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1566 const GstStructure *structure;
1568 g_return_if_fail (GST_IS_EVENT (event));
1569 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1571 structure = GST_EVENT_STRUCTURE (event);
1574 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1575 (structure, GST_QUARK (MESSAGE))));
1579 * gst_event_new_stream_start:
1580 * @stream_id: Identifier for this stream
1582 * Create a new STREAM_START event. The stream start event can only
1583 * travel downstream synchronized with the buffer flow. It is expected
1584 * to be the first event that is sent for a new stream.
1586 * Source elements, demuxers and other elements that create new streams
1587 * are supposed to send this event as the first event of a new stream. It
1588 * should not be sent after a flushing seek or in similar situations
1589 * and is used to mark the beginning of a new logical stream. Elements
1590 * combining multiple streams must ensure that this event is only forwarded
1591 * downstream once and not for every single input stream.
1593 * The @stream_id should be a unique string that consists of the upstream
1594 * stream-id, / as separator and a unique stream-id for this specific
1595 * stream. A new stream-id should only be created for a stream if the upstream
1596 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1597 * but not for every single element in the pipeline.
1598 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1599 * used to create a stream-id. There are no particular semantics for the
1600 * stream-id, though it should be deterministic (to support stream matching)
1601 * and it might be used to order streams (besides any information conveyed by
1604 * Returns: (transfer full): the new STREAM_START event.
1607 gst_event_new_stream_start (const gchar * stream_id)
1611 g_return_val_if_fail (stream_id != NULL, NULL);
1613 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1614 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1615 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1617 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1621 * gst_event_parse_stream_start:
1622 * @event: a stream-start event.
1623 * @stream_id: (out) (transfer none): pointer to store the stream-id
1625 * Parse a stream-id @event and store the result in the given @stream_id
1626 * location. The string stored in @stream_id must not be modified and will
1627 * remain valid only until @event gets freed. Make a copy if you want to
1628 * modify it or store it for later use.
1631 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1633 const GstStructure *structure;
1636 g_return_if_fail (event != NULL);
1637 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1639 structure = gst_event_get_structure (event);
1640 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1643 *stream_id = g_value_get_string (val);
1647 * gst_event_set_stream:
1648 * @event: a stream-start event
1649 * @stream: (transfer none): the stream object to set
1651 * Set the @stream on the stream-start @event
1656 gst_event_set_stream (GstEvent * event, GstStream * stream)
1658 g_return_if_fail (event != NULL);
1659 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1660 g_return_if_fail (gst_event_is_writable (event));
1662 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1663 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1667 * gst_event_parse_stream:
1668 * @event: a stream-start event
1669 * @stream: (out) (transfer full): address of variable to store the stream
1671 * Parse a stream-start @event and extract the #GstStream from it.
1676 gst_event_parse_stream (GstEvent * event, GstStream ** stream)
1678 g_return_if_fail (event != NULL);
1679 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1682 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1683 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1689 * gst_event_set_stream_flags:
1690 * @event: a stream-start event
1691 * @flags: the stream flags to set
1696 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1698 g_return_if_fail (event != NULL);
1699 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1700 g_return_if_fail (gst_event_is_writable (event));
1702 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1703 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1707 * gst_event_parse_stream_flags:
1708 * @event: a stream-start event
1709 * @flags: (out): address of variable where to store the stream flags
1714 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1716 g_return_if_fail (event != NULL);
1717 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1720 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1721 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1726 * gst_event_set_group_id:
1727 * @event: a stream-start event
1728 * @group_id: the group id to set
1730 * All streams that have the same group id are supposed to be played
1731 * together, i.e. all streams inside a container file should have the
1732 * same group id but different stream ids. The group id should change
1733 * each time the stream is started, resulting in different group ids
1734 * each time a file is played for example.
1736 * Use gst_util_group_id_next() to get a new group id.
1741 gst_event_set_group_id (GstEvent * event, guint group_id)
1743 g_return_if_fail (event != NULL);
1744 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1745 g_return_if_fail (gst_event_is_writable (event));
1747 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1748 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1752 * gst_event_parse_group_id:
1753 * @event: a stream-start event
1754 * @group_id: (out): address of variable where to store the group id
1756 * Returns: %TRUE if a group id was set on the event and could be parsed,
1762 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1764 g_return_val_if_fail (event != NULL, FALSE);
1765 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1769 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1770 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1777 * gst_event_new_stream_collection:
1778 * @collection: Active collection for this data flow
1780 * Create a new STREAM_COLLECTION event. The stream collection event can only
1781 * travel downstream synchronized with the buffer flow.
1783 * Source elements, demuxers and other elements that manage collections
1784 * of streams and post #GstStreamCollection messages on the bus also send
1785 * this event downstream on each pad involved in the collection, so that
1786 * activation of a new collection can be tracked through the downstream
1789 * Returns: (transfer full): the new STREAM_COLLECTION event.
1794 gst_event_new_stream_collection (GstStreamCollection * collection)
1798 g_return_val_if_fail (collection != NULL, NULL);
1799 g_return_val_if_fail (GST_IS_STREAM_COLLECTION (collection), NULL);
1801 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_COLLECTION),
1802 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1804 return gst_event_new_custom (GST_EVENT_STREAM_COLLECTION, s);
1808 * gst_event_parse_stream_collection:
1809 * @event: a stream-collection event
1810 * @collection: (out): pointer to store the collection
1812 * Retrieve new #GstStreamCollection from STREAM_COLLECTION event @event.
1817 gst_event_parse_stream_collection (GstEvent * event,
1818 GstStreamCollection ** collection)
1820 const GstStructure *structure;
1822 g_return_if_fail (event != NULL);
1823 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_COLLECTION);
1825 structure = gst_event_get_structure (event);
1828 gst_structure_id_get (structure,
1829 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1834 * gst_event_new_toc:
1835 * @toc: (transfer none): #GstToc structure.
1836 * @updated: whether @toc was updated or not.
1838 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1839 * inform elements that some kind of the TOC was found.
1841 * Returns: (transfer full): a new #GstEvent.
1844 gst_event_new_toc (GstToc * toc, gboolean updated)
1846 GstStructure *toc_struct;
1849 g_return_val_if_fail (toc != NULL, NULL);
1851 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1853 /* need different structure names so sticky_multi event stuff on pads
1854 * works, i.e. both TOC events are kept around */
1855 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1856 id = GST_QUARK (EVENT_TOC_GLOBAL);
1858 id = GST_QUARK (EVENT_TOC_CURRENT);
1860 toc_struct = gst_structure_new_id (id,
1861 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1862 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1864 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1868 * gst_event_parse_toc:
1869 * @event: a TOC event.
1870 * @toc: (out) (transfer full): pointer to #GstToc structure.
1871 * @updated: (out): pointer to store TOC updated flag.
1873 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1876 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1878 const GstStructure *structure;
1880 g_return_if_fail (event != NULL);
1881 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1882 g_return_if_fail (toc != NULL);
1884 structure = gst_event_get_structure (event);
1886 gst_structure_id_get (structure,
1887 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1888 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1892 * gst_event_new_toc_select:
1893 * @uid: UID in the TOC to start playback from.
1895 * Generate a TOC select event with the given @uid. The purpose of the
1896 * TOC select event is to start playback based on the TOC's entry with the
1899 * Returns: a new #GstEvent.
1902 gst_event_new_toc_select (const gchar * uid)
1904 GstStructure *structure;
1906 g_return_val_if_fail (uid != NULL, NULL);
1908 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1910 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1911 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1913 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1917 * gst_event_parse_toc_select:
1918 * @event: a TOC select event.
1919 * @uid: (out) (transfer full) (allow-none): storage for the selection UID.
1921 * Parse a TOC select @event and store the results in the given @uid location.
1924 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1926 const GstStructure *structure;
1929 g_return_if_fail (event != NULL);
1930 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1932 structure = gst_event_get_structure (event);
1933 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1936 *uid = g_strdup (g_value_get_string (val));
1941 * gst_event_new_protection:
1942 * @system_id: (transfer none): a string holding a UUID that uniquely
1943 * identifies a protection system.
1944 * @data: (transfer none): a #GstBuffer holding protection system specific
1945 * information. The reference count of the buffer will be incremented by one.
1946 * @origin: a string indicating where the protection
1947 * information carried in the event was extracted from. The allowed values
1948 * of this string will depend upon the protection scheme.
1950 * Creates a new event containing information specific to a particular
1951 * protection system (uniquely identified by @system_id), by which that
1952 * protection system can acquire key(s) to decrypt a protected stream.
1954 * In order for a decryption element to decrypt media
1955 * protected using a specific system, it first needs all the
1956 * protection system specific information necessary to acquire the decryption
1957 * key(s) for that stream. The functions defined here enable this information
1958 * to be passed in events from elements that extract it
1959 * (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter
1960 * elements that use it.
1962 * Events containing protection system specific information are created using
1963 * #gst_event_new_protection, and they can be parsed by downstream elements
1964 * using #gst_event_parse_protection.
1966 * In Common Encryption, protection system specific information may be located
1967 * within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof)
1968 * boxes; it may also be contained in ContentProtection elements within MPEG
1969 * DASH MPDs. The events created by #gst_event_new_protection contain data
1970 * identifying from which of these locations the encapsulated protection system
1971 * specific information originated. This origin information is required as
1972 * some protection systems use different encodings depending upon where the
1973 * information originates.
1975 * The events returned by gst_event_new_protection() are implemented
1976 * in such a way as to ensure that the most recently-pushed protection info
1977 * event of a particular @origin and @system_id will
1978 * be stuck to the output pad of the sending element.
1980 * Returns: a #GST_EVENT_PROTECTION event, if successful; %NULL
1986 gst_event_new_protection (const gchar * system_id,
1987 GstBuffer * data, const gchar * origin)
1993 g_return_val_if_fail (system_id != NULL, NULL);
1994 g_return_val_if_fail (data != NULL, NULL);
1997 g_strconcat ("GstProtectionEvent", origin ? "-" : "",
1998 origin ? origin : "", "-", system_id, NULL);
2000 GST_CAT_INFO (GST_CAT_EVENT, "creating protection event %s", event_name);
2002 s = gst_structure_new (event_name, "data", GST_TYPE_BUFFER, data,
2003 "system_id", G_TYPE_STRING, system_id, NULL);
2005 gst_structure_set (s, "origin", G_TYPE_STRING, origin, NULL);
2006 event = gst_event_new_custom (GST_EVENT_PROTECTION, s);
2008 g_free (event_name);
2013 * gst_event_parse_protection:
2014 * @event: a #GST_EVENT_PROTECTION event.
2015 * @system_id: (out) (allow-none) (transfer none): pointer to store the UUID
2016 * string uniquely identifying a content protection system.
2017 * @data: (out) (allow-none) (transfer none): pointer to store a #GstBuffer
2018 * holding protection system specific information.
2019 * @origin: (out) (allow-none) (transfer none): pointer to store a value that
2020 * indicates where the protection information carried by @event was extracted
2023 * Parses an event containing protection system specific information and stores
2024 * the results in @system_id, @data and @origin. The data stored in @system_id,
2025 * @origin and @data are valid until @event is released.
2030 gst_event_parse_protection (GstEvent * event, const gchar ** system_id,
2031 GstBuffer ** data, const gchar ** origin)
2033 const GstStructure *s;
2035 g_return_if_fail (event != NULL);
2036 g_return_if_fail (GST_IS_EVENT (event));
2037 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_PROTECTION);
2039 s = gst_event_get_structure (event);
2042 *origin = gst_structure_get_string (s, "origin");
2045 *system_id = gst_structure_get_string (s, "system_id");
2048 const GValue *value = gst_structure_get_value (s, "data");
2049 *data = gst_value_get_buffer (value);
2054 * gst_event_new_segment_done:
2055 * @format: The format of the position being done
2056 * @position: The position of the segment being done
2058 * Create a new segment-done event. This event is sent by elements that
2059 * finish playback of a segment as a result of a segment seek.
2061 * Returns: (transfer full): a new #GstEvent
2064 gst_event_new_segment_done (GstFormat format, gint64 position)
2067 GstStructure *structure;
2069 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
2071 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
2072 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
2073 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
2075 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
2081 * gst_event_parse_segment_done:
2082 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
2083 * @format: (out) (allow-none): Result location for the format, or %NULL
2084 * @position: (out) (allow-none): Result location for the position, or %NULL
2086 * Extracts the position and format from the segment done message.
2090 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
2093 const GstStructure *structure;
2096 g_return_if_fail (event != NULL);
2097 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
2099 structure = gst_event_get_structure (event);
2101 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
2103 *format = g_value_get_enum (val);
2105 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
2106 if (position != NULL)
2107 *position = g_value_get_int64 (val);