2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wim.taymans@chello.be>
4 * 2005 Wim Taymans <wim@fluendo.com>
6 * gstevent.c: GstEvent subsystem
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
26 * @short_description: Structure describing events that are passed up and down
28 * @see_also: #GstPad, #GstElement
30 * The event class provides factory methods to construct events for sending
31 * and functions to query (parse) received events.
33 * Events are usually created with gst_event_new_*() which takes event-type
34 * specific parameters as arguments.
35 * To send an event application will usually use gst_element_send_event() and
36 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 * The event should be unreffed with gst_event_unref() if it has not been sent.
39 * Events that have been received can be parsed with their respective
40 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
42 * Events are passed between elements in parallel to the data stream. Some events
43 * are serialized with buffers, others are not. Some events only travel downstream,
44 * others only upstream. Some events can travel both upstream and downstream.
46 * The events are used to signal special conditions in the datastream such as
47 * EOS (end of stream) or the start of a new stream-segment.
48 * Events are also used to flush the pipeline of any pending data.
50 * Most of the event API is used inside plugins. Applications usually only
51 * construct and use seek events.
52 * To do that gst_event_new_seek() is used to create a seek event. It takes
53 * the needed parameters to specify seeking time and mode.
54 * |[<!-- language="C" -->
58 * // construct a seek event to play the media from second 2 to 5, flush
59 * // the pipeline to decrease latency.
60 * event = gst_event_new_seek (1.0,
62 * GST_SEEK_FLAG_FLUSH,
63 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
64 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
66 * result = gst_element_send_event (pipeline, event);
68 * g_warning ("seek failed");
74 #include "gst_private.h"
75 #include <string.h> /* memcpy */
79 #include "gstenumtypes.h"
84 GType _gst_event_type = 0;
90 GstStructure *structure;
91 gint64 running_time_offset;
94 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
103 static GstEventQuarks event_quarks[] = {
104 {GST_EVENT_UNKNOWN, "unknown", 0},
105 {GST_EVENT_FLUSH_START, "flush-start", 0},
106 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
107 {GST_EVENT_SELECT_STREAMS, "select-streams", 0},
108 {GST_EVENT_STREAM_START, "stream-start", 0},
109 {GST_EVENT_STREAM_COLLECTION, "stream-collection", 0},
110 {GST_EVENT_CAPS, "caps", 0},
111 {GST_EVENT_SEGMENT, "segment", 0},
112 {GST_EVENT_TAG, "tag", 0},
113 {GST_EVENT_TOC, "toc", 0},
114 {GST_EVENT_PROTECTION, "protection", 0},
115 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
116 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
117 {GST_EVENT_EOS, "eos", 0},
118 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
119 {GST_EVENT_GAP, "gap", 0},
120 {GST_EVENT_QOS, "qos", 0},
121 {GST_EVENT_SEEK, "seek", 0},
122 {GST_EVENT_NAVIGATION, "navigation", 0},
123 {GST_EVENT_LATENCY, "latency", 0},
124 {GST_EVENT_STEP, "step", 0},
125 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
126 {GST_EVENT_TOC_SELECT, "toc-select", 0},
127 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
128 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
129 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
130 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
131 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
132 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
137 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
140 _priv_gst_event_initialize (void)
144 _gst_event_type = gst_event_get_type ();
146 g_type_class_ref (gst_seek_flags_get_type ());
147 g_type_class_ref (gst_seek_type_get_type ());
149 for (i = 0; event_quarks[i].name; i++) {
150 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
155 * gst_event_type_get_name:
156 * @type: the event type
158 * Get a printable name for the given event type. Do not modify or free.
160 * Returns: a reference to the static name of the event.
163 gst_event_type_get_name (GstEventType type)
167 for (i = 0; event_quarks[i].name; i++) {
168 if (type == event_quarks[i].type)
169 return event_quarks[i].name;
175 * gst_event_type_to_quark:
176 * @type: the event type
178 * Get the unique quark for the given event type.
180 * Returns: the quark associated with the event type
183 gst_event_type_to_quark (GstEventType type)
187 for (i = 0; event_quarks[i].name; i++) {
188 if (type == event_quarks[i].type)
189 return event_quarks[i].quark;
195 * gst_event_type_get_flags:
196 * @type: a #GstEventType
198 * Gets the #GstEventTypeFlags associated with @type.
200 * Returns: a #GstEventTypeFlags.
203 gst_event_type_get_flags (GstEventType type)
205 GstEventTypeFlags ret;
207 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
213 _gst_event_free (GstEvent * event)
217 g_return_if_fail (event != NULL);
218 g_return_if_fail (GST_IS_EVENT (event));
220 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
221 GST_EVENT_TYPE_NAME (event));
223 s = GST_EVENT_STRUCTURE (event);
226 gst_structure_set_parent_refcount (s, NULL);
227 gst_structure_free (s);
230 g_slice_free1 (sizeof (GstEventImpl), event);
233 static void gst_event_init (GstEventImpl * event, GstEventType type);
236 _gst_event_copy (GstEvent * event)
241 copy = g_slice_new0 (GstEventImpl);
243 gst_event_init (copy, GST_EVENT_TYPE (event));
245 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
246 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
248 s = GST_EVENT_STRUCTURE (event);
250 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
251 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
252 ©->event.mini_object.refcount);
254 GST_EVENT_STRUCTURE (copy) = NULL;
257 ((GstEventImpl *) copy)->running_time_offset =
258 ((GstEventImpl *) event)->running_time_offset;
260 return GST_EVENT_CAST (copy);
264 gst_event_init (GstEventImpl * event, GstEventType type)
266 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
267 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
268 (GstMiniObjectFreeFunction) _gst_event_free);
270 GST_EVENT_TYPE (event) = type;
271 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
272 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
273 event->running_time_offset = 0;
278 * gst_event_new_custom:
279 * @type: The type of the new event
280 * @structure: (transfer full): the structure for the event. The event will
281 * take ownership of the structure.
283 * Create a new custom-typed event. This can be used for anything not
284 * handled by other event-specific functions to pass an event to another
287 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
288 * assigning a free number and filling in the correct direction and
289 * serialization flags.
291 * New custom events can also be created by subclassing the event type if
294 * Returns: (transfer full): the new custom event.
297 gst_event_new_custom (GstEventType type, GstStructure * structure)
301 event = g_slice_new0 (GstEventImpl);
303 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
304 gst_event_type_get_name (type), type);
307 /* structure must not have a parent */
308 if (!gst_structure_set_parent_refcount (structure,
309 &event->event.mini_object.refcount))
313 gst_event_init (event, type);
315 GST_EVENT_STRUCTURE (event) = structure;
317 return GST_EVENT_CAST (event);
322 g_slice_free1 (sizeof (GstEventImpl), event);
323 g_warning ("structure is already owned by another object");
329 * gst_event_get_structure:
330 * @event: The #GstEvent.
332 * Access the structure of the event.
334 * Returns: The structure of the event. The structure is still
335 * owned by the event, which means that you should not free it and
336 * that the pointer becomes invalid when you free the event.
341 gst_event_get_structure (GstEvent * event)
343 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
345 return GST_EVENT_STRUCTURE (event);
349 * gst_event_writable_structure:
350 * @event: The #GstEvent.
352 * Get a writable version of the structure.
354 * Returns: (transfer none): The structure of the event. The structure
355 * is still owned by the event, which means that you should not free
356 * it and that the pointer becomes invalid when you free the event.
357 * This function checks if @event is writable and will never return
363 gst_event_writable_structure (GstEvent * event)
365 GstStructure *structure;
367 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
368 g_return_val_if_fail (gst_event_is_writable (event), NULL);
370 structure = GST_EVENT_STRUCTURE (event);
372 if (structure == NULL) {
374 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
376 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
377 GST_EVENT_STRUCTURE (event) = structure;
383 * gst_event_has_name:
384 * @event: The #GstEvent.
385 * @name: name to check
387 * Checks if @event has the given @name. This function is usually used to
388 * check the name of a custom event.
390 * Returns: %TRUE if @name matches the name of the event structure.
393 gst_event_has_name (GstEvent * event, const gchar * name)
395 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
397 if (GST_EVENT_STRUCTURE (event) == NULL)
400 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
404 * gst_event_get_seqnum:
405 * @event: A #GstEvent.
407 * Retrieve the sequence number of a event.
409 * Events have ever-incrementing sequence numbers, which may also be set
410 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
411 * indicate that a event corresponds to some other set of events or messages,
412 * for example an EOS event corresponding to a SEEK event. It is considered good
413 * practice to make this correspondence when possible, though it is not
416 * Note that events and messages share the same sequence number incrementor;
417 * two events or messages will never have the same sequence number unless
418 * that correspondence was made explicitly.
420 * Returns: The event's sequence number.
425 gst_event_get_seqnum (GstEvent * event)
427 g_return_val_if_fail (GST_IS_EVENT (event), -1);
429 return GST_EVENT_SEQNUM (event);
433 * gst_event_set_seqnum:
434 * @event: A #GstEvent.
435 * @seqnum: A sequence number.
437 * Set the sequence number of a event.
439 * This function might be called by the creator of a event to indicate that the
440 * event relates to other events or messages. See gst_event_get_seqnum() for
446 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
448 g_return_if_fail (GST_IS_EVENT (event));
450 GST_EVENT_SEQNUM (event) = seqnum;
454 * gst_event_get_running_time_offset:
455 * @event: A #GstEvent.
457 * Retrieve the accumulated running time offset of the event.
459 * Events passing through #GstPads that have a running time
460 * offset set via gst_pad_set_offset() will get their offset
461 * adjusted according to the pad's offset.
463 * If the event contains any information that related to the
464 * running time, this information will need to be updated
465 * before usage with this offset.
467 * Returns: The event's running time offset
474 gst_event_get_running_time_offset (GstEvent * event)
476 g_return_val_if_fail (GST_IS_EVENT (event), 0);
478 return ((GstEventImpl *) event)->running_time_offset;
482 * gst_event_set_running_time_offset:
483 * @event: A #GstEvent.
484 * @offset: A the new running time offset
486 * Set the running time offset of a event. See
487 * gst_event_get_running_time_offset() for more information.
494 gst_event_set_running_time_offset (GstEvent * event, gint64 offset)
496 g_return_if_fail (GST_IS_EVENT (event));
498 ((GstEventImpl *) event)->running_time_offset = offset;
502 * gst_event_new_flush_start:
504 * Allocate a new flush start event. The flush start event can be sent
505 * upstream and downstream and travels out-of-bounds with the dataflow.
507 * It marks pads as being flushing and will make them return
508 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
509 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
510 * Any event (except a #GST_EVENT_FLUSH_STOP) received
511 * on a flushing pad will return %FALSE immediately.
513 * Elements should unlock any blocking functions and exit their streaming
514 * functions as fast as possible when this event is received.
516 * This event is typically generated after a seek to flush out all queued data
517 * in the pipeline so that the new media is played as soon as possible.
519 * Returns: (transfer full): a new flush start event.
522 gst_event_new_flush_start (void)
524 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
528 * gst_event_new_flush_stop:
529 * @reset_time: if time should be reset
531 * Allocate a new flush stop event. The flush stop event can be sent
532 * upstream and downstream and travels serialized with the dataflow.
533 * It is typically sent after sending a FLUSH_START event to make the
534 * pads accept data again.
536 * Elements can process this event synchronized with the dataflow since
537 * the preceding FLUSH_START event stopped the dataflow.
539 * This event is typically generated to complete a seek and to resume
542 * Returns: (transfer full): a new flush stop event.
545 gst_event_new_flush_stop (gboolean reset_time)
549 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
551 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
552 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
553 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
559 * gst_event_parse_flush_stop:
560 * @event: The event to parse
561 * @reset_time: (out): if time should be reset
563 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
566 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
568 GstStructure *structure;
570 g_return_if_fail (GST_IS_EVENT (event));
571 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
573 structure = GST_EVENT_STRUCTURE (event);
574 if (G_LIKELY (reset_time))
576 g_value_get_boolean (gst_structure_id_get_value (structure,
577 GST_QUARK (RESET_TIME)));
581 * gst_event_new_select_streams:
582 * @streams: (element-type gchar) (transfer none): the list of streams to
585 * Allocate a new select-streams event.
587 * The select-streams event requests the specified @streams to be activated.
589 * The list of @streams corresponds to the "Stream ID" of each stream to be
590 * activated. Those ID can be obtained via the #GstStream objects present
591 * in #GST_EVENT_STREAM_START, #GST_EVENT_STREAM_COLLECTION or
592 * #GST_MESSSAGE_STREAM_COLLECTION.
594 * Returns: (transfer full): a new select-streams event.
599 gst_event_new_select_streams (GList * streams)
602 GValue val = G_VALUE_INIT;
606 GST_CAT_INFO (GST_CAT_EVENT, "Creating new select-streams event");
607 struc = gst_structure_new_id_empty (GST_QUARK (EVENT_SELECT_STREAMS));
608 g_value_init (&val, GST_TYPE_LIST);
609 /* Fill struc with streams */
610 for (tmpl = streams; tmpl; tmpl = tmpl->next) {
611 GValue strval = G_VALUE_INIT;
612 const gchar *str = (const gchar *) tmpl->data;
613 g_value_init (&strval, G_TYPE_STRING);
614 g_value_set_string (&strval, str);
615 gst_value_list_append_and_take_value (&val, &strval);
617 gst_structure_id_take_value (struc, GST_QUARK (STREAMS), &val);
618 event = gst_event_new_custom (GST_EVENT_SELECT_STREAMS, struc);
624 * gst_event_parse_select_streams:
625 * @event: The event to parse
626 * @streams: (out) (element-type gchar) (transfer full): the streams
628 * Parse the SELECT_STREAMS event and retrieve the contained streams.
633 gst_event_parse_select_streams (GstEvent * event, GList ** streams)
635 GstStructure *structure;
638 g_return_if_fail (GST_IS_EVENT (event));
639 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SELECT_STREAMS);
641 structure = GST_EVENT_STRUCTURE (event);
642 if (G_LIKELY (streams)) {
643 const GValue *vlist =
644 gst_structure_id_get_value (structure, GST_QUARK (STREAMS));
645 guint i, sz = gst_value_list_get_size (vlist);
646 for (i = 0; i < sz; i++) {
647 const GValue *strv = gst_value_list_get_value (vlist, i);
648 res = g_list_append (res, g_value_dup_string (strv));
658 * Create a new EOS event. The eos event can only travel downstream
659 * synchronized with the buffer flow. Elements that receive the EOS
660 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
661 * when data after the EOS event arrives.
663 * The EOS event will travel down to the sink elements in the pipeline
664 * which will then post the #GST_MESSAGE_EOS on the bus after they have
665 * finished playing any buffered data.
667 * When all sinks have posted an EOS message, an EOS message is
668 * forwarded to the application.
670 * The EOS event itself will not cause any state transitions of the pipeline.
672 * Returns: (transfer full): the new EOS event.
675 gst_event_new_eos (void)
677 return gst_event_new_custom (GST_EVENT_EOS, NULL);
682 * @timestamp: the start time (pts) of the gap
683 * @duration: the duration of the gap
685 * Create a new GAP event. A gap event can be thought of as conceptually
686 * equivalent to a buffer to signal that there is no data for a certain
687 * amount of time. This is useful to signal a gap to downstream elements
688 * which may wait for data, such as muxers or mixers or overlays, especially
689 * for sparse streams such as subtitle streams.
691 * Returns: (transfer full): the new GAP event.
694 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
698 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
700 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
701 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
702 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
703 GST_TIME_ARGS (duration));
705 event = gst_event_new_custom (GST_EVENT_GAP,
706 gst_structure_new_id (GST_QUARK (EVENT_GAP),
707 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
708 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
714 * gst_event_parse_gap:
715 * @event: a #GstEvent of type #GST_EVENT_GAP
716 * @timestamp: (out) (allow-none): location where to store the
717 * start time (pts) of the gap, or %NULL
718 * @duration: (out) (allow-none): location where to store the duration of
721 * Extract timestamp and duration from a new GAP event.
724 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
725 GstClockTime * duration)
727 GstStructure *structure;
729 g_return_if_fail (GST_IS_EVENT (event));
730 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
732 structure = GST_EVENT_STRUCTURE (event);
733 gst_structure_id_get (structure,
734 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
735 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
739 * gst_event_new_caps:
740 * @caps: (transfer none): a #GstCaps
742 * Create a new CAPS event for @caps. The caps event can only travel downstream
743 * synchronized with the buffer flow and contains the format of the buffers
744 * that will follow after the event.
746 * Returns: (transfer full): the new CAPS event.
749 gst_event_new_caps (GstCaps * caps)
753 g_return_val_if_fail (caps != NULL, NULL);
754 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
756 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
758 event = gst_event_new_custom (GST_EVENT_CAPS,
759 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
760 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
766 * gst_event_parse_caps:
767 * @event: The event to parse
768 * @caps: (out) (transfer none): A pointer to the caps
770 * Get the caps from @event. The caps remains valid as long as @event remains
774 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
776 GstStructure *structure;
778 g_return_if_fail (GST_IS_EVENT (event));
779 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
781 structure = GST_EVENT_STRUCTURE (event);
784 g_value_get_boxed (gst_structure_id_get_value (structure,
789 * gst_event_new_segment:
790 * @segment: (transfer none): a #GstSegment
792 * Create a new SEGMENT event for @segment. The segment event can only travel
793 * downstream synchronized with the buffer flow and contains timing information
794 * and playback properties for the buffers that will follow.
796 * The segment event marks the range of buffers to be processed. All
797 * data not within the segment range is not to be processed. This can be
798 * used intelligently by plugins to apply more efficient methods of skipping
799 * unneeded data. The valid range is expressed with the @start and @stop
802 * The time value of the segment is used in conjunction with the start
803 * value to convert the buffer timestamps into the stream time. This is
804 * usually done in sinks to report the current stream_time.
805 * @time represents the stream_time of a buffer carrying a timestamp of
806 * @start. @time cannot be -1.
808 * @start cannot be -1, @stop can be -1. If there
809 * is a valid @stop given, it must be greater or equal the @start, including
810 * when the indicated playback @rate is < 0.
812 * The @applied_rate value provides information about any rate adjustment that
813 * has already been made to the timestamps and content on the buffers of the
814 * stream. (@rate * @applied_rate) should always equal the rate that has been
815 * requested for playback. For example, if an element has an input segment
816 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
817 * incoming timestamps and buffer content by half and output a segment event
818 * with @rate of 1.0 and @applied_rate of 2.0
820 * After a segment event, the buffer stream time is calculated with:
822 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
824 * Returns: (transfer full): the new SEGMENT event.
827 gst_event_new_segment (const GstSegment * segment)
831 g_return_val_if_fail (segment != NULL, NULL);
832 g_return_val_if_fail (segment->rate != 0.0, NULL);
833 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
834 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
836 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
839 event = gst_event_new_custom (GST_EVENT_SEGMENT,
840 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
841 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
847 * gst_event_parse_segment:
848 * @event: The event to parse
849 * @segment: (out) (transfer none): a pointer to a #GstSegment
851 * Parses a segment @event and stores the result in the given @segment location.
852 * @segment remains valid only until the @event is freed. Don't modify the segment
853 * and make a copy if you want to modify it or store it for later use.
856 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
858 GstStructure *structure;
860 g_return_if_fail (GST_IS_EVENT (event));
861 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
864 structure = GST_EVENT_STRUCTURE (event);
865 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
866 GST_QUARK (SEGMENT)));
871 * gst_event_copy_segment:
872 * @event: The event to parse
873 * @segment: a pointer to a #GstSegment
875 * Parses a segment @event and copies the #GstSegment into the location
879 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
881 const GstSegment *src;
883 g_return_if_fail (GST_IS_EVENT (event));
884 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
887 gst_event_parse_segment (event, &src);
888 gst_segment_copy_into (src, segment);
894 * @taglist: (transfer full): metadata list. The event will take ownership
897 * Generates a metadata tag event from the given @taglist.
899 * The scope of the taglist specifies if the taglist applies to the
900 * complete medium or only to this specific stream. As the tag event
901 * is a sticky event, elements should merge tags received from
902 * upstream with a given scope with their own tags with the same
903 * scope and create a new tag event from it.
905 * Returns: (transfer full): a new #GstEvent
908 gst_event_new_tag (GstTagList * taglist)
911 GValue val = G_VALUE_INIT;
912 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
914 g_return_val_if_fail (taglist != NULL, NULL);
916 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
917 g_value_init (&val, GST_TYPE_TAG_LIST);
918 g_value_take_boxed (&val, taglist);
919 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
920 return gst_event_new_custom (GST_EVENT_TAG, s);
924 * gst_event_parse_tag:
925 * @event: a tag event
926 * @taglist: (out) (transfer none): pointer to metadata list
928 * Parses a tag @event and stores the results in the given @taglist location.
929 * No reference to the taglist will be returned, it remains valid only until
930 * the @event is freed. Don't modify or free the taglist, make a copy if you
931 * want to modify it or store it for later use.
934 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
938 g_return_if_fail (GST_IS_EVENT (event));
939 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
941 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
942 GST_QUARK (TAGLIST));
945 *taglist = (GstTagList *) g_value_get_boxed (val);
948 /* buffersize event */
950 * gst_event_new_buffer_size:
951 * @format: buffer format
952 * @minsize: minimum buffer size
953 * @maxsize: maximum buffer size
954 * @async: thread behavior
956 * Create a new buffersize event. The event is sent downstream and notifies
957 * elements that they should provide a buffer of the specified dimensions.
959 * When the @async flag is set, a thread boundary is preferred.
961 * Returns: (transfer full): a new #GstEvent
964 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
965 gint64 maxsize, gboolean async)
968 GstStructure *structure;
970 GST_CAT_INFO (GST_CAT_EVENT,
971 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
972 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
973 minsize, maxsize, async);
975 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
976 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
977 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
978 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
979 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
980 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
986 * gst_event_parse_buffer_size:
987 * @event: The event to query
988 * @format: (out): A pointer to store the format in
989 * @minsize: (out): A pointer to store the minsize in
990 * @maxsize: (out): A pointer to store the maxsize in
991 * @async: (out): A pointer to store the async-flag in
993 * Get the format, minsize, maxsize and async-flag in the buffersize event.
996 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
997 gint64 * minsize, gint64 * maxsize, gboolean * async)
999 const GstStructure *structure;
1001 g_return_if_fail (GST_IS_EVENT (event));
1002 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1004 structure = GST_EVENT_STRUCTURE (event);
1006 *format = (GstFormat)
1007 g_value_get_enum (gst_structure_id_get_value (structure,
1008 GST_QUARK (FORMAT)));
1011 g_value_get_int64 (gst_structure_id_get_value (structure,
1012 GST_QUARK (MINSIZE)));
1015 g_value_get_int64 (gst_structure_id_get_value (structure,
1016 GST_QUARK (MAXSIZE)));
1019 g_value_get_boolean (gst_structure_id_get_value (structure,
1020 GST_QUARK (ASYNC)));
1024 * gst_event_new_qos:
1025 * @type: the QoS type
1026 * @proportion: the proportion of the qos message
1027 * @diff: The time difference of the last Clock sync
1028 * @timestamp: The timestamp of the buffer
1030 * Allocate a new qos event with the given values.
1031 * The QOS event is generated in an element that wants an upstream
1032 * element to either reduce or increase its rate because of
1033 * high/low CPU load or other resource usage such as network performance or
1034 * throttling. Typically sinks generate these events for each buffer
1037 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1038 * used when a buffer arrived in time or when the sink cannot keep up with
1039 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1040 * receiving buffers fast enough and thus has to drop late buffers.
1041 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1042 * by the application, for example to reduce power consumption.
1044 * @proportion indicates the real-time performance of the streaming in the
1045 * element that generated the QoS event (usually the sink). The value is
1046 * generally computed based on more long term statistics about the streams
1047 * timestamps compared to the clock.
1048 * A value < 1.0 indicates that the upstream element is producing data faster
1049 * than real-time. A value > 1.0 indicates that the upstream element is not
1050 * producing data fast enough. 1.0 is the ideal @proportion value. The
1051 * proportion value can safely be used to lower or increase the quality of
1054 * @diff is the difference against the clock in running time of the last
1055 * buffer that caused the element to generate the QOS event. A negative value
1056 * means that the buffer with @timestamp arrived in time. A positive value
1057 * indicates how late the buffer with @timestamp was. When throttling is
1058 * enabled, @diff will be set to the requested throttling interval.
1060 * @timestamp is the timestamp of the last buffer that cause the element
1061 * to generate the QOS event. It is expressed in running time and thus an ever
1064 * The upstream element can use the @diff and @timestamp values to decide
1065 * whether to process more buffers. For positive @diff, all buffers with
1066 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1067 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1068 * result smaller than 0 is not allowed.
1070 * The application can use general event probes to intercept the QoS
1071 * event and implement custom application specific QoS handling.
1073 * Returns: (transfer full): a new QOS event.
1076 gst_event_new_qos (GstQOSType type, gdouble proportion,
1077 GstClockTimeDiff diff, GstClockTime timestamp)
1080 GstStructure *structure;
1082 /* diff must be positive or timestamp + diff must be positive */
1083 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1085 GST_CAT_LOG (GST_CAT_EVENT,
1086 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1087 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1088 diff, GST_TIME_ARGS (timestamp));
1090 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1091 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1092 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1093 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1094 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1095 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1101 * gst_event_parse_qos:
1102 * @event: The event to query
1103 * @type: (out): A pointer to store the QoS type in
1104 * @proportion: (out): A pointer to store the proportion in
1105 * @diff: (out): A pointer to store the diff in
1106 * @timestamp: (out): A pointer to store the timestamp in
1108 * Get the type, proportion, diff and timestamp in the qos event. See
1109 * gst_event_new_qos() for more information about the different QoS values.
1111 * @timestamp will be adjusted for any pad offsets of pads it was passing through.
1114 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1115 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1117 const GstStructure *structure;
1119 g_return_if_fail (GST_IS_EVENT (event));
1120 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1122 structure = GST_EVENT_STRUCTURE (event);
1124 *type = (GstQOSType)
1125 g_value_get_enum (gst_structure_id_get_value (structure,
1129 g_value_get_double (gst_structure_id_get_value (structure,
1130 GST_QUARK (PROPORTION)));
1133 g_value_get_int64 (gst_structure_id_get_value (structure,
1136 gint64 offset = gst_event_get_running_time_offset (event);
1137 GstClockTimeDiff diff_ =
1138 g_value_get_int64 (gst_structure_id_get_value (structure,
1142 g_value_get_uint64 (gst_structure_id_get_value (structure,
1143 GST_QUARK (TIMESTAMP)));
1144 /* Catch underflows */
1145 if (*timestamp > -offset)
1146 *timestamp += offset;
1150 /* Make sure that timestamp + diff is always >= 0. Because
1151 * of the running time offset this might not be true */
1152 if (diff_ < 0 && *timestamp < -diff_)
1153 *timestamp = (GstClockTime) - diff_;
1158 * gst_event_new_seek:
1159 * @rate: The new playback rate
1160 * @format: The format of the seek values
1161 * @flags: The optional seek flags
1162 * @start_type: The type and flags for the new start position
1163 * @start: The value of the new start position
1164 * @stop_type: The type and flags for the new stop position
1165 * @stop: The value of the new stop position
1167 * Allocate a new seek event with the given parameters.
1169 * The seek event configures playback of the pipeline between @start to @stop
1170 * at the speed given in @rate, also called a playback segment.
1171 * The @start and @stop values are expressed in @format.
1173 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1174 * Negatives values means backwards playback. A value of 0.0 for the
1175 * rate is not allowed and should be accomplished instead by PAUSING the
1178 * A pipeline has a default playback segment configured with a start
1179 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1180 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1182 * @start_type and @stop_type specify how to adjust the currently configured
1183 * start and stop fields in playback segment. Adjustments can be made relative
1184 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1185 * means that the position should not be updated.
1187 * When the rate is positive and @start has been updated, playback will start
1188 * from the newly configured start position.
1190 * For negative rates, playback will start from the newly configured stop
1191 * position (if any). If the stop position is updated, it must be different from
1192 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1194 * It is not possible to seek relative to the current playback position, to do
1195 * this, PAUSE the pipeline, query the current playback position with
1196 * #GST_QUERY_POSITION and update the playback segment current position with a
1197 * #GST_SEEK_TYPE_SET to the desired position.
1199 * Returns: (transfer full): a new seek event.
1202 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1203 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1206 GstStructure *structure;
1208 g_return_val_if_fail (rate != 0.0, NULL);
1210 if (format == GST_FORMAT_TIME) {
1211 GST_CAT_INFO (GST_CAT_EVENT,
1212 "creating seek rate %lf, format TIME, flags %d, "
1213 "start_type %d, start %" GST_TIME_FORMAT ", "
1214 "stop_type %d, stop %" GST_TIME_FORMAT,
1215 rate, flags, start_type, GST_TIME_ARGS (start),
1216 stop_type, GST_TIME_ARGS (stop));
1218 GST_CAT_INFO (GST_CAT_EVENT,
1219 "creating seek rate %lf, format %s, flags %d, "
1220 "start_type %d, start %" G_GINT64_FORMAT ", "
1221 "stop_type %d, stop %" G_GINT64_FORMAT,
1222 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1226 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1227 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1228 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1229 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1230 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1231 GST_QUARK (CUR), G_TYPE_INT64, start,
1232 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1233 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1234 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1240 * gst_event_parse_seek:
1241 * @event: a seek event
1242 * @rate: (out): result location for the rate
1243 * @format: (out): result location for the stream format
1244 * @flags: (out): result location for the #GstSeekFlags
1245 * @start_type: (out): result location for the #GstSeekType of the start position
1246 * @start: (out): result location for the start position expressed in @format
1247 * @stop_type: (out): result location for the #GstSeekType of the stop position
1248 * @stop: (out): result location for the stop position expressed in @format
1250 * Parses a seek @event and stores the results in the given result locations.
1253 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1254 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1255 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1257 const GstStructure *structure;
1259 g_return_if_fail (GST_IS_EVENT (event));
1260 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1262 structure = GST_EVENT_STRUCTURE (event);
1265 g_value_get_double (gst_structure_id_get_value (structure,
1268 *format = (GstFormat)
1269 g_value_get_enum (gst_structure_id_get_value (structure,
1270 GST_QUARK (FORMAT)));
1272 *flags = (GstSeekFlags)
1273 g_value_get_flags (gst_structure_id_get_value (structure,
1274 GST_QUARK (FLAGS)));
1276 *start_type = (GstSeekType)
1277 g_value_get_enum (gst_structure_id_get_value (structure,
1278 GST_QUARK (CUR_TYPE)));
1281 g_value_get_int64 (gst_structure_id_get_value (structure,
1284 *stop_type = (GstSeekType)
1285 g_value_get_enum (gst_structure_id_get_value (structure,
1286 GST_QUARK (STOP_TYPE)));
1289 g_value_get_int64 (gst_structure_id_get_value (structure,
1294 * gst_event_new_navigation:
1295 * @structure: (transfer full): description of the event. The event will take
1296 * ownership of the structure.
1298 * Create a new navigation event from the given description.
1300 * Returns: (transfer full): a new #GstEvent
1303 gst_event_new_navigation (GstStructure * structure)
1305 g_return_val_if_fail (structure != NULL, NULL);
1307 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1311 * gst_event_new_latency:
1312 * @latency: the new latency value
1314 * Create a new latency event. The event is sent upstream from the sinks and
1315 * notifies elements that they should add an additional @latency to the
1316 * running time before synchronising against the clock.
1318 * The latency is mostly used in live sinks and is always expressed in
1321 * Returns: (transfer full): a new #GstEvent
1324 gst_event_new_latency (GstClockTime latency)
1327 GstStructure *structure;
1329 GST_CAT_INFO (GST_CAT_EVENT,
1330 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1332 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1333 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1334 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1340 * gst_event_parse_latency:
1341 * @event: The event to query
1342 * @latency: (out): A pointer to store the latency in.
1344 * Get the latency in the latency event.
1347 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1349 g_return_if_fail (GST_IS_EVENT (event));
1350 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1354 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1355 (event), GST_QUARK (LATENCY)));
1359 * gst_event_new_step:
1360 * @format: the format of @amount
1361 * @amount: the amount of data to step
1362 * @rate: the step rate
1363 * @flush: flushing steps
1364 * @intermediate: intermediate steps
1366 * Create a new step event. The purpose of the step event is to instruct a sink
1367 * to skip @amount (expressed in @format) of media. It can be used to implement
1368 * stepping through the video frame by frame or for doing fast trick modes.
1370 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1371 * = 0.0 or first reverse the direction of playback using a seek event to get
1372 * the same effect as rate < 0.0.
1374 * The @flush flag will clear any pending data in the pipeline before starting
1375 * the step operation.
1377 * The @intermediate flag instructs the pipeline that this step operation is
1378 * part of a larger step operation.
1380 * Returns: (transfer full): a new #GstEvent
1383 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1384 gboolean flush, gboolean intermediate)
1387 GstStructure *structure;
1389 g_return_val_if_fail (rate > 0.0, NULL);
1391 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1393 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1394 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1395 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1396 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1397 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1398 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1399 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1405 * gst_event_parse_step:
1406 * @event: The event to query
1407 * @format: (out) (allow-none): a pointer to store the format in
1408 * @amount: (out) (allow-none): a pointer to store the amount in
1409 * @rate: (out) (allow-none): a pointer to store the rate in
1410 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1411 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1414 * Parse the step event.
1417 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1418 gdouble * rate, gboolean * flush, gboolean * intermediate)
1420 const GstStructure *structure;
1422 g_return_if_fail (GST_IS_EVENT (event));
1423 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1425 structure = GST_EVENT_STRUCTURE (event);
1428 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1429 GST_QUARK (FORMAT)));
1431 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1432 GST_QUARK (AMOUNT)));
1434 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1437 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1438 GST_QUARK (FLUSH)));
1440 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1441 GST_QUARK (INTERMEDIATE)));
1445 * gst_event_new_reconfigure:
1447 * Create a new reconfigure event. The purpose of the reconfigure event is
1448 * to travel upstream and make elements renegotiate their caps or reconfigure
1449 * their buffer pools. This is useful when changing properties on elements
1450 * or changing the topology of the pipeline.
1452 * Returns: (transfer full): a new #GstEvent
1455 gst_event_new_reconfigure (void)
1459 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1461 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1467 * gst_event_new_sink_message:
1468 * @name: a name for the event
1469 * @msg: (transfer none): the #GstMessage to be posted
1471 * Create a new sink-message event. The purpose of the sink-message event is
1472 * to instruct a sink to post the message contained in the event synchronized
1475 * @name is used to store multiple sticky events on one pad.
1477 * Returns: (transfer full): a new #GstEvent
1479 /* FIXME 2.0: take ownership of msg for consistency? */
1481 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1484 GstStructure *structure;
1486 g_return_val_if_fail (msg != NULL, NULL);
1488 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1490 structure = gst_structure_new_id (g_quark_from_string (name),
1491 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1492 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1498 * gst_event_parse_sink_message:
1499 * @event: The event to query
1500 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1502 * Parse the sink-message event. Unref @msg after usage.
1505 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1507 const GstStructure *structure;
1509 g_return_if_fail (GST_IS_EVENT (event));
1510 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1512 structure = GST_EVENT_STRUCTURE (event);
1515 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1516 (structure, GST_QUARK (MESSAGE))));
1520 * gst_event_new_stream_start:
1521 * @stream_id: Identifier for this stream
1523 * Create a new STREAM_START event. The stream start event can only
1524 * travel downstream synchronized with the buffer flow. It is expected
1525 * to be the first event that is sent for a new stream.
1527 * Source elements, demuxers and other elements that create new streams
1528 * are supposed to send this event as the first event of a new stream. It
1529 * should not be sent after a flushing seek or in similar situations
1530 * and is used to mark the beginning of a new logical stream. Elements
1531 * combining multiple streams must ensure that this event is only forwarded
1532 * downstream once and not for every single input stream.
1534 * The @stream_id should be a unique string that consists of the upstream
1535 * stream-id, / as separator and a unique stream-id for this specific
1536 * stream. A new stream-id should only be created for a stream if the upstream
1537 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1538 * but not for every single element in the pipeline.
1539 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1540 * used to create a stream-id. There are no particular semantics for the
1541 * stream-id, though it should be deterministic (to support stream matching)
1542 * and it might be used to order streams (besides any information conveyed by
1545 * Returns: (transfer full): the new STREAM_START event.
1548 gst_event_new_stream_start (const gchar * stream_id)
1552 g_return_val_if_fail (stream_id != NULL, NULL);
1554 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1555 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1556 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1558 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1562 * gst_event_parse_stream_start:
1563 * @event: a stream-start event.
1564 * @stream_id: (out) (transfer none): pointer to store the stream-id
1566 * Parse a stream-id @event and store the result in the given @stream_id
1567 * location. The string stored in @stream_id must not be modified and will
1568 * remain valid only until @event gets freed. Make a copy if you want to
1569 * modify it or store it for later use.
1572 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1574 const GstStructure *structure;
1577 g_return_if_fail (event != NULL);
1578 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1580 structure = gst_event_get_structure (event);
1581 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1584 *stream_id = g_value_get_string (val);
1588 * gst_event_set_stream:
1589 * @event: a stream-start event
1590 * @stream: (transfer none): the stream object to set
1592 * Set the @stream on the stream-start @event
1597 gst_event_set_stream (GstEvent * event, GstStream * stream)
1599 g_return_if_fail (event != NULL);
1600 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1601 g_return_if_fail (gst_event_is_writable (event));
1603 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1604 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1608 * gst_event_parse_stream:
1609 * @event: a stream-start event
1610 * @stream: (out) (transfer full): adress of variable to store the stream
1612 * Parse a stream-start @event and extract the #GstStream from it.
1617 gst_event_parse_stream (GstEvent * event, GstStream ** stream)
1619 g_return_if_fail (event != NULL);
1620 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1623 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1624 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1630 * gst_event_set_stream_flags:
1631 * @event: a stream-start event
1632 * @flags: the stream flags to set
1637 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1639 g_return_if_fail (event != NULL);
1640 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1641 g_return_if_fail (gst_event_is_writable (event));
1643 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1644 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1648 * gst_event_parse_stream_flags:
1649 * @event: a stream-start event
1650 * @flags: (out): address of variable where to store the stream flags
1655 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1657 g_return_if_fail (event != NULL);
1658 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1661 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1662 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1667 * gst_event_set_group_id:
1668 * @event: a stream-start event
1669 * @group_id: the group id to set
1671 * All streams that have the same group id are supposed to be played
1672 * together, i.e. all streams inside a container file should have the
1673 * same group id but different stream ids. The group id should change
1674 * each time the stream is started, resulting in different group ids
1675 * each time a file is played for example.
1677 * Use gst_util_group_id_next() to get a new group id.
1682 gst_event_set_group_id (GstEvent * event, guint group_id)
1684 g_return_if_fail (event != NULL);
1685 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1686 g_return_if_fail (gst_event_is_writable (event));
1688 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1689 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1693 * gst_event_parse_group_id:
1694 * @event: a stream-start event
1695 * @group_id: (out): address of variable where to store the group id
1697 * Returns: %TRUE if a group id was set on the event and could be parsed,
1703 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1705 g_return_val_if_fail (event != NULL, FALSE);
1706 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1710 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1711 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1718 * gst_event_new_stream_collection:
1719 * @collection: Active collection for this data flow
1721 * Create a new STREAM_COLLECTION event. The stream collection event can only
1722 * travel downstream synchronized with the buffer flow.
1724 * Source elements, demuxers and other elements that manage collections
1725 * of streams and post #GstStreamCollection messages on the bus also send
1726 * this event downstream on each pad involved in the collection, so that
1727 * activation of a new collection can be tracked through the downstream
1730 * Returns: (transfer full): the new STREAM_COLLECTION event.
1735 gst_event_new_stream_collection (GstStreamCollection * collection)
1739 g_return_val_if_fail (collection != NULL, NULL);
1740 g_return_val_if_fail (GST_IS_STREAM_COLLECTION (collection), NULL);
1742 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_COLLECTION),
1743 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1745 return gst_event_new_custom (GST_EVENT_STREAM_COLLECTION, s);
1749 * gst_event_parse_stream_collection:
1750 * @event: a stream-collection event
1751 * @collection: (out): pointer to store the collection
1753 * Retrieve new #GstStreamCollection from STREAM_COLLECTION event @event.
1758 gst_event_parse_stream_collection (GstEvent * event,
1759 GstStreamCollection ** collection)
1761 const GstStructure *structure;
1763 g_return_if_fail (event != NULL);
1764 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_COLLECTION);
1766 structure = gst_event_get_structure (event);
1769 gst_structure_id_get (structure,
1770 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1775 * gst_event_new_toc:
1776 * @toc: (transfer none): #GstToc structure.
1777 * @updated: whether @toc was updated or not.
1779 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1780 * inform elements that some kind of the TOC was found.
1782 * Returns: (transfer full): a new #GstEvent.
1785 gst_event_new_toc (GstToc * toc, gboolean updated)
1787 GstStructure *toc_struct;
1790 g_return_val_if_fail (toc != NULL, NULL);
1792 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1794 /* need different structure names so sticky_multi event stuff on pads
1795 * works, i.e. both TOC events are kept around */
1796 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1797 id = GST_QUARK (EVENT_TOC_GLOBAL);
1799 id = GST_QUARK (EVENT_TOC_CURRENT);
1801 toc_struct = gst_structure_new_id (id,
1802 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1803 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1805 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1809 * gst_event_parse_toc:
1810 * @event: a TOC event.
1811 * @toc: (out) (transfer full): pointer to #GstToc structure.
1812 * @updated: (out): pointer to store TOC updated flag.
1814 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1817 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1819 const GstStructure *structure;
1821 g_return_if_fail (event != NULL);
1822 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1823 g_return_if_fail (toc != NULL);
1825 structure = gst_event_get_structure (event);
1827 gst_structure_id_get (structure,
1828 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1829 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1833 * gst_event_new_toc_select:
1834 * @uid: UID in the TOC to start playback from.
1836 * Generate a TOC select event with the given @uid. The purpose of the
1837 * TOC select event is to start playback based on the TOC's entry with the
1840 * Returns: a new #GstEvent.
1843 gst_event_new_toc_select (const gchar * uid)
1845 GstStructure *structure;
1847 g_return_val_if_fail (uid != NULL, NULL);
1849 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1851 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1852 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1854 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1858 * gst_event_parse_toc_select:
1859 * @event: a TOC select event.
1860 * @uid: (out) (transfer full) (allow-none): storage for the selection UID.
1862 * Parse a TOC select @event and store the results in the given @uid location.
1865 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1867 const GstStructure *structure;
1870 g_return_if_fail (event != NULL);
1871 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1873 structure = gst_event_get_structure (event);
1874 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1877 *uid = g_strdup (g_value_get_string (val));
1882 * gst_event_new_protection:
1883 * @system_id: (transfer none): a string holding a UUID that uniquely
1884 * identifies a protection system.
1885 * @data: (transfer none): a #GstBuffer holding protection system specific
1886 * information. The reference count of the buffer will be incremented by one.
1887 * @origin: a string indicating where the protection
1888 * information carried in the event was extracted from. The allowed values
1889 * of this string will depend upon the protection scheme.
1891 * Creates a new event containing information specific to a particular
1892 * protection system (uniquely identified by @system_id), by which that
1893 * protection system can acquire key(s) to decrypt a protected stream.
1895 * In order for a decryption element to decrypt media
1896 * protected using a specific system, it first needs all the
1897 * protection system specific information necessary to acquire the decryption
1898 * key(s) for that stream. The functions defined here enable this information
1899 * to be passed in events from elements that extract it
1900 * (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter
1901 * elements that use it.
1903 * Events containing protection system specific information are created using
1904 * #gst_event_new_protection, and they can be parsed by downstream elements
1905 * using #gst_event_parse_protection.
1907 * In Common Encryption, protection system specific information may be located
1908 * within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof)
1909 * boxes; it may also be contained in ContentProtection elements within MPEG
1910 * DASH MPDs. The events created by #gst_event_new_protection contain data
1911 * identifying from which of these locations the encapsulated protection system
1912 * specific information originated. This origin information is required as
1913 * some protection systems use different encodings depending upon where the
1914 * information originates.
1916 * The events returned by gst_event_new_protection() are implemented
1917 * in such a way as to ensure that the most recently-pushed protection info
1918 * event of a particular @origin and @system_id will
1919 * be stuck to the output pad of the sending element.
1921 * Returns: a #GST_EVENT_PROTECTION event, if successful; %NULL
1927 gst_event_new_protection (const gchar * system_id,
1928 GstBuffer * data, const gchar * origin)
1934 g_return_val_if_fail (system_id != NULL, NULL);
1935 g_return_val_if_fail (data != NULL, NULL);
1938 g_strconcat ("GstProtectionEvent", origin ? "-" : "",
1939 origin ? origin : "", "-", system_id, NULL);
1941 GST_CAT_INFO (GST_CAT_EVENT, "creating protection event %s", event_name);
1943 s = gst_structure_new (event_name, "data", GST_TYPE_BUFFER, data,
1944 "system_id", G_TYPE_STRING, system_id, NULL);
1946 gst_structure_set (s, "origin", G_TYPE_STRING, origin, NULL);
1947 event = gst_event_new_custom (GST_EVENT_PROTECTION, s);
1949 g_free (event_name);
1954 * gst_event_parse_protection:
1955 * @event: a #GST_EVENT_PROTECTION event.
1956 * @system_id: (out) (allow-none) (transfer none): pointer to store the UUID
1957 * string uniquely identifying a content protection system.
1958 * @data: (out) (allow-none) (transfer none): pointer to store a #GstBuffer
1959 * holding protection system specific information.
1960 * @origin: (allow-none) (transfer none): pointer to store a value that
1961 * indicates where the protection information carried by @event was extracted
1964 * Parses an event containing protection system specific information and stores
1965 * the results in @system_id, @data and @origin. The data stored in @system_id,
1966 * @origin and @data are valid until @event is released.
1971 gst_event_parse_protection (GstEvent * event, const gchar ** system_id,
1972 GstBuffer ** data, const gchar ** origin)
1974 const GstStructure *s;
1976 g_return_if_fail (event != NULL);
1977 g_return_if_fail (GST_IS_EVENT (event));
1978 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_PROTECTION);
1980 s = gst_event_get_structure (event);
1983 *origin = gst_structure_get_string (s, "origin");
1986 *system_id = gst_structure_get_string (s, "system_id");
1989 const GValue *value = gst_structure_get_value (s, "data");
1990 *data = gst_value_get_buffer (value);
1995 * gst_event_new_segment_done:
1996 * @format: The format of the position being done
1997 * @position: The position of the segment being done
1999 * Create a new segment-done event. This event is sent by elements that
2000 * finish playback of a segment as a result of a segment seek.
2002 * Returns: (transfer full): a new #GstEvent
2005 gst_event_new_segment_done (GstFormat format, gint64 position)
2008 GstStructure *structure;
2010 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
2012 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
2013 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
2014 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
2016 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
2022 * gst_event_parse_segment_done:
2023 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
2024 * @format: (out) (allow-none): Result location for the format, or %NULL
2025 * @position: (out) (allow-none): Result location for the position, or %NULL
2027 * Extracts the position and format from the segment done message.
2031 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
2034 const GstStructure *structure;
2037 g_return_if_fail (event != NULL);
2038 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
2040 structure = gst_event_get_structure (event);
2042 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
2044 *format = g_value_get_enum (val);
2046 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
2047 if (position != NULL)
2048 *position = g_value_get_int64 (val);