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., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
26 * @short_description: Structure describing events that are passed up and down
28 * @see_also: #GstPad, #GstElement
30 * The event class provides factory methods to construct events for sending
31 * and functions to query (parse) received events.
33 * Events are usually created with gst_event_new_*() which takes event-type
34 * specific parameters as arguments.
35 * To send an event application will usually use gst_element_send_event() and
36 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 * The event should be unreffed with gst_event_unref() if it has not been sent.
39 * Events that have been received can be parsed with their respective
40 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
42 * Events are passed between elements in parallel to the data stream. Some events
43 * are serialized with buffers, others are not. Some events only travel downstream,
44 * others only upstream. Some events can travel both upstream and downstream.
46 * The events are used to signal special conditions in the datastream such as
47 * EOS (end of stream) or the start of a new stream-segment.
48 * Events are also used to flush the pipeline of any pending data.
50 * Most of the event API is used inside plugins. Applications usually only
51 * construct and use seek events.
52 * To do that gst_event_new_seek() is used to create a seek event. It takes
53 * the needed parameters to specify seeking time and mode.
55 * <title>performing a seek on a pipeline</title>
60 * // construct a seek event to play the media from second 2 to 5, flush
61 * // the pipeline to decrease latency.
62 * event = gst_event_new_seek (1.0,
64 * GST_SEEK_FLAG_FLUSH,
65 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
66 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
68 * result = gst_element_send_event (pipeline, event);
70 * g_warning ("seek failed");
75 * Last reviewed on 2012-03-28 (0.11.3)
79 #include "gst_private.h"
80 #include <string.h> /* memcpy */
84 #include "gstenumtypes.h"
89 GType _gst_event_type = 0;
97 GstStructure *structure;
100 #define GST_EVENT_SLICE_SIZE(e) (((GstEventImpl *)(e))->slice_size)
101 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
110 static GstEventQuarks event_quarks[] = {
111 {GST_EVENT_UNKNOWN, "unknown", 0},
112 {GST_EVENT_FLUSH_START, "flush-start", 0},
113 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
114 {GST_EVENT_STREAM_START, "stream-start", 0},
115 {GST_EVENT_CAPS, "caps", 0},
116 {GST_EVENT_STREAM_CONFIG, "stream-config", 0},
117 {GST_EVENT_SEGMENT, "segment", 0},
118 {GST_EVENT_TAG, "tag", 0},
119 {GST_EVENT_TOC, "toc", 0},
120 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
121 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
122 {GST_EVENT_EOS, "eos", 0},
123 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
124 {GST_EVENT_GAP, "gap", 0},
125 {GST_EVENT_QOS, "qos", 0},
126 {GST_EVENT_SEEK, "seek", 0},
127 {GST_EVENT_NAVIGATION, "navigation", 0},
128 {GST_EVENT_LATENCY, "latency", 0},
129 {GST_EVENT_STEP, "step", 0},
130 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
131 {GST_EVENT_TOC_SELECT, "toc-select", 0},
132 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
133 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
134 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
135 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
136 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
137 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
142 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
145 _priv_gst_event_initialize (void)
149 _gst_event_type = gst_event_get_type ();
151 g_type_class_ref (gst_seek_flags_get_type ());
152 g_type_class_ref (gst_seek_type_get_type ());
154 for (i = 0; event_quarks[i].name; i++) {
155 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
160 * gst_event_type_get_name:
161 * @type: the event type
163 * Get a printable name for the given event type. Do not modify or free.
165 * Returns: a reference to the static name of the event.
168 gst_event_type_get_name (GstEventType type)
172 for (i = 0; event_quarks[i].name; i++) {
173 if (type == event_quarks[i].type)
174 return event_quarks[i].name;
180 * gst_event_type_to_quark:
181 * @type: the event type
183 * Get the unique quark for the given event type.
185 * Returns: the quark associated with the event type
188 gst_event_type_to_quark (GstEventType type)
192 for (i = 0; event_quarks[i].name; i++) {
193 if (type == event_quarks[i].type)
194 return event_quarks[i].quark;
200 * gst_event_type_get_flags:
201 * @type: a #GstEventType
203 * Gets the #GstEventTypeFlags associated with @type.
205 * Returns: a #GstEventTypeFlags.
208 gst_event_type_get_flags (GstEventType type)
210 GstEventTypeFlags ret;
212 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
218 _gst_event_free (GstEvent * event)
222 g_return_if_fail (event != NULL);
223 g_return_if_fail (GST_IS_EVENT (event));
225 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
226 GST_EVENT_TYPE_NAME (event));
228 s = GST_EVENT_STRUCTURE (event);
231 gst_structure_set_parent_refcount (s, NULL);
232 gst_structure_free (s);
235 g_slice_free1 (GST_EVENT_SLICE_SIZE (event), event);
238 static void gst_event_init (GstEventImpl * event, gsize size,
242 _gst_event_copy (GstEvent * event)
247 copy = g_slice_new0 (GstEventImpl);
249 gst_event_init (copy, sizeof (GstEventImpl), GST_EVENT_TYPE (event));
251 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
252 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
254 s = GST_EVENT_STRUCTURE (event);
256 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
257 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
258 ©->event.mini_object.refcount);
260 GST_EVENT_STRUCTURE (copy) = NULL;
262 return GST_EVENT_CAST (copy);
266 gst_event_init (GstEventImpl * event, gsize size, GstEventType type)
268 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type);
270 event->event.mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
271 event->event.mini_object.free = (GstMiniObjectFreeFunction) _gst_event_free;
273 GST_EVENT_SLICE_SIZE (event) = size;
275 GST_EVENT_TYPE (event) = type;
276 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
277 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
282 * gst_event_new_custom:
283 * @type: The type of the new event
284 * @structure: (transfer full): the structure for the event. The event will
285 * take ownership of the structure.
287 * Create a new custom-typed event. This can be used for anything not
288 * handled by other event-specific functions to pass an event to another
291 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
292 * assigning a free number and filling in the correct direction and
293 * serialization flags.
295 * New custom events can also be created by subclassing the event type if
298 * Returns: (transfer full): the new custom event.
301 gst_event_new_custom (GstEventType type, GstStructure * structure)
305 event = g_slice_new0 (GstEventImpl);
307 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
308 gst_event_type_get_name (type), type);
311 /* structure must not have a parent */
312 if (!gst_structure_set_parent_refcount (structure,
313 &event->event.mini_object.refcount))
317 gst_event_init (event, sizeof (GstEventImpl), type);
319 GST_EVENT_STRUCTURE (event) = structure;
321 return GST_EVENT_CAST (event);
326 g_slice_free1 (GST_EVENT_SLICE_SIZE (event), event);
327 g_warning ("structure is already owned by another object");
333 * gst_event_get_structure:
334 * @event: The #GstEvent.
336 * Access the structure of the event.
338 * Returns: The structure of the event. The structure is still
339 * owned by the event, which means that you should not free it and
340 * that the pointer becomes invalid when you free the event.
345 gst_event_get_structure (GstEvent * event)
347 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
349 return GST_EVENT_STRUCTURE (event);
353 * gst_event_writable_structure:
354 * @event: The #GstEvent.
356 * Get a writable version of the structure.
358 * Returns: The structure of the event. The structure is still
359 * owned by the event, which means that you should not free it and
360 * that the pointer becomes invalid when you free the event.
361 * This function checks if @event is writable and will never return NULL.
366 gst_event_writable_structure (GstEvent * event)
368 GstStructure *structure;
370 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
371 g_return_val_if_fail (gst_event_is_writable (event), NULL);
373 structure = GST_EVENT_STRUCTURE (event);
375 if (structure == NULL) {
377 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
379 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
380 GST_EVENT_STRUCTURE (event) = structure;
386 * gst_event_has_name:
387 * @event: The #GstEvent.
388 * @name: name to check
390 * Checks if @event has the given @name. This function is usually used to
391 * check the name of a custom event.
393 * Returns: %TRUE if @name matches the name of the event structure.
398 gst_event_has_name (GstEvent * event, const gchar * name)
400 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
402 if (GST_EVENT_STRUCTURE (event) == NULL)
405 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
409 * gst_event_get_seqnum:
410 * @event: A #GstEvent.
412 * Retrieve the sequence number of a event.
414 * Events have ever-incrementing sequence numbers, which may also be set
415 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
416 * indicate that a event corresponds to some other set of events or messages,
417 * for example an EOS event corresponding to a SEEK event. It is considered good
418 * practice to make this correspondence when possible, though it is not
421 * Note that events and messages share the same sequence number incrementor;
422 * two events or messages will never have the same sequence number unless
423 * that correspondence was made explicitly.
425 * Returns: The event's sequence number.
432 gst_event_get_seqnum (GstEvent * event)
434 g_return_val_if_fail (GST_IS_EVENT (event), -1);
436 return GST_EVENT_SEQNUM (event);
440 * gst_event_set_seqnum:
441 * @event: A #GstEvent.
442 * @seqnum: A sequence number.
444 * Set the sequence number of a event.
446 * This function might be called by the creator of a event to indicate that the
447 * event relates to other events or messages. See gst_event_get_seqnum() for
455 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
457 g_return_if_fail (GST_IS_EVENT (event));
459 GST_EVENT_SEQNUM (event) = seqnum;
463 * gst_event_new_flush_start:
465 * Allocate a new flush start event. The flush start event can be sent
466 * upstream and downstream and travels out-of-bounds with the dataflow.
468 * It marks pads as being flushing and will make them return
469 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
470 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
471 * Any event (except a #GST_EVENT_FLUSH_STOP) received
472 * on a flushing pad will return %FALSE immediately.
474 * Elements should unlock any blocking functions and exit their streaming
475 * functions as fast as possible when this event is received.
477 * This event is typically generated after a seek to flush out all queued data
478 * in the pipeline so that the new media is played as soon as possible.
480 * Returns: (transfer full): a new flush start event.
483 gst_event_new_flush_start (void)
485 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
489 * gst_event_new_flush_stop:
490 * @reset_time: if time should be reset
492 * Allocate a new flush stop event. The flush stop event can be sent
493 * upstream and downstream and travels serialized with the dataflow.
494 * It is typically sent after sending a FLUSH_START event to make the
495 * pads accept data again.
497 * Elements can process this event synchronized with the dataflow since
498 * the preceeding FLUSH_START event stopped the dataflow.
500 * This event is typically generated to complete a seek and to resume
503 * Returns: (transfer full): a new flush stop event.
506 gst_event_new_flush_stop (gboolean reset_time)
510 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
512 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
513 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
514 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
520 * gst_event_parse_flush_stop:
521 * @event: The event to parse
522 * @reset_time: (out): if time should be reset
524 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
527 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
529 GstStructure *structure;
531 g_return_if_fail (GST_IS_EVENT (event));
532 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
534 structure = GST_EVENT_STRUCTURE (event);
535 if (G_LIKELY (reset_time))
537 g_value_get_boolean (gst_structure_id_get_value (structure,
538 GST_QUARK (RESET_TIME)));
544 * Create a new EOS event. The eos event can only travel downstream
545 * synchronized with the buffer flow. Elements that receive the EOS
546 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
547 * when data after the EOS event arrives.
549 * The EOS event will travel down to the sink elements in the pipeline
550 * which will then post the #GST_MESSAGE_EOS on the bus after they have
551 * finished playing any buffered data.
553 * When all sinks have posted an EOS message, an EOS message is
554 * forwarded to the application.
556 * The EOS event itself will not cause any state transitions of the pipeline.
558 * Returns: (transfer full): the new EOS event.
561 gst_event_new_eos (void)
563 return gst_event_new_custom (GST_EVENT_EOS, NULL);
568 * @timestamp: the start time (pts) of the gap
569 * @duration: the duration of the gap
571 * Create a new GAP event. A gap event can be thought of as conceptually
572 * equivalent to a buffer to signal that there is no data for a certain
573 * amount of time. This is useful to signal a gap to downstream elements
574 * which may wait for data, such as muxers or mixers or overlays, especially
575 * for sparse streams such as subtitle streams.
577 * Returns: (transfer full): the new GAP event.
580 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
584 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
585 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (duration), NULL);
587 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
588 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
589 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
590 GST_TIME_ARGS (duration));
592 event = gst_event_new_custom (GST_EVENT_GAP,
593 gst_structure_new_id (GST_QUARK (EVENT_GAP),
594 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
595 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
601 * gst_event_parse_gap:
602 * @event: a #GstEvent of type #GST_EVENT_GAP
603 * @timestamp: (out) (allow-none): location where to store the
604 * start time (pts) of the gap, or %NULL
605 * @duration: (out) (allow-none): location where to store the duration of
608 * Extract timestamp and duration from a new GAP event.
611 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
612 GstClockTime * duration)
614 GstStructure *structure;
616 g_return_if_fail (GST_IS_EVENT (event));
617 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
619 structure = GST_EVENT_STRUCTURE (event);
620 gst_structure_id_get (structure,
621 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
622 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
626 * gst_event_new_caps:
627 * @caps: (transfer none): a #GstCaps
629 * Create a new CAPS event for @caps. The caps event can only travel downstream
630 * synchronized with the buffer flow and contains the format of the buffers
631 * that will follow after the event.
633 * Returns: (transfer full): the new CAPS event.
636 gst_event_new_caps (GstCaps * caps)
640 g_return_val_if_fail (caps != NULL, NULL);
641 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
643 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
645 event = gst_event_new_custom (GST_EVENT_CAPS,
646 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
647 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
653 * gst_event_parse_caps:
654 * @event: The event to parse
655 * @caps: (out): A pointer to the caps
657 * Get the caps from @event. The caps remains valid as long as @event remains
661 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
663 GstStructure *structure;
665 g_return_if_fail (GST_IS_EVENT (event));
666 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
668 structure = GST_EVENT_STRUCTURE (event);
671 g_value_get_boxed (gst_structure_id_get_value (structure,
676 * gst_event_new_stream_config:
677 * @flags: the stream config flags
679 * Create a new STREAM CONFIG event. The stream config event travels
680 * downstream synchronized with the buffer flow and contains stream
681 * configuration information for the stream, such as stream-headers
682 * or setup-data. It is optional and should be sent after the CAPS
685 * Returns: (transfer full): the new STREAM CONFIG event.
688 gst_event_new_stream_config (GstStreamConfigFlags flags)
692 GST_CAT_INFO (GST_CAT_EVENT, "creating stream info event, flags=0x%x", flags);
694 event = gst_event_new_custom (GST_EVENT_STREAM_CONFIG,
695 gst_structure_new_id (GST_QUARK (EVENT_STREAM_CONFIG),
696 GST_QUARK (FLAGS), GST_TYPE_STREAM_CONFIG_FLAGS, flags, NULL));
702 * gst_event_parse_stream_config:
703 * @event: The event to parse
704 * @flags: (out): a pointer to a variable to store the stream config flags
706 * Get the stream config flags from @event.
709 gst_event_parse_stream_config (GstEvent * event, GstStreamConfigFlags * flags)
711 GstStructure *structure;
713 g_return_if_fail (GST_IS_EVENT (event));
714 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG);
716 structure = GST_EVENT_STRUCTURE (event);
717 if (G_LIKELY (flags != NULL)) {
719 g_value_get_enum (gst_structure_id_get_value (structure,
725 * gst_event_set_stream_config_setup_data:
726 * @event: a stream config event
727 * @buf: a #GstBuffer with setup data
729 * Set setup data on the stream info event to signal out of bound setup data
730 * to downstream elements. Unlike stream headers, setup data contains data
731 * that is required to interpret the data stream, but is not valid as-is
732 * inside the data stream and thus can't just be prepended to or inserted
733 * into the data stream.
736 gst_event_set_stream_config_setup_data (GstEvent * event, GstBuffer * buf)
740 g_return_if_fail (GST_IS_EVENT (event));
741 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG);
742 g_return_if_fail (GST_IS_BUFFER (buf) && gst_buffer_get_size (buf) > 0);
744 s = GST_EVENT_STRUCTURE (event);
745 gst_structure_id_set (s, GST_QUARK (SETUP_DATA), GST_TYPE_BUFFER, buf, NULL);
749 * gst_event_parse_stream_config_setup_data:
750 * @event: a stream config event
751 * @buf: (out) (transfer none): location where to store the #GstBuffer with setup data
753 * Extracts the setup data buffer from the stream info event. Will store
754 * %NULL in @buf if the event contains no setup data. The buffer returned
755 * will remain valid as long as @event remains valid. The caller should
756 * acquire a reference to to @buf if needed.
758 * Returns: TRUE if @event contained setup data and @buf has been set,
762 gst_event_parse_stream_config_setup_data (GstEvent * event, GstBuffer ** buf)
767 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
768 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG,
770 g_return_val_if_fail (buf != NULL, FALSE);
772 s = GST_EVENT_STRUCTURE (event);
773 val = gst_structure_id_get_value (s, GST_QUARK (SETUP_DATA));
775 *buf = g_value_get_boxed (val);
779 return (*buf != NULL);
783 * gst_event_add_stream_config_header:
784 * @event: a stream config event
785 * @buf: a #GstBuffer with stream header data
787 * Adds a stream header to the stream info event to signal stream headers to
788 * to downstream elements such as multifilesink, tcpserversink etc. Stream
789 * headers can be and should usually be prepended to the data stream at any
790 * point in the stream (which requires a streamable format), e.g. to a new
791 * client connecting, or when starting a new file segment. stream header
792 * buffers will all be used together in the order they were added to the
793 * stream config event. Stream headers are sent as buffers at the beginning
794 * of the data flow in addition to the stream config event. Elements that
795 * care about stream headers need to make sure that they don't insert or
796 * interpret these header buffers twice if they interpret them.
799 gst_event_add_stream_config_header (GstEvent * event, GstBuffer * buf)
802 GValue buf_val = { 0, };
805 g_return_if_fail (GST_IS_EVENT (event));
806 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG);
807 g_return_if_fail (GST_IS_BUFFER (buf) && gst_buffer_get_size (buf) > 0);
809 g_value_init (&buf_val, GST_TYPE_BUFFER);
810 g_value_set_boxed (&buf_val, buf);
812 s = GST_EVENT_STRUCTURE (event);
813 val = (GValue *) gst_structure_id_get_value (s, GST_QUARK (STREAM_HEADERS));
815 GValue new_array = { 0, };
817 g_value_init (&new_array, GST_TYPE_ARRAY);
818 gst_value_array_append_value (&new_array, &buf_val);
819 gst_structure_id_take_value (s, GST_QUARK (STREAM_HEADERS), &new_array);
821 gst_value_array_append_value (val, &buf_val);
823 g_value_unset (&buf_val);
827 * gst_event_get_n_stream_config_headers:
828 * @event: a stream config event
830 * Extract the number of stream header buffers.
832 * Returns: the number of stream header buffers attached to the stream info
836 gst_event_get_n_stream_config_headers (GstEvent * event)
842 g_return_val_if_fail (GST_IS_EVENT (event), 0);
843 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG, 0);
845 s = GST_EVENT_STRUCTURE (event);
846 val = gst_structure_id_get_value (s, GST_QUARK (STREAM_HEADERS));
849 num = gst_value_array_get_size (val);
855 * gst_event_parse_nth_stream_config_header:
856 * @event: a stream config event
857 * @index: number of the stream header to retrieve
858 * @buf: (out) (transfer none): location where to store the n-th stream
861 * Retrieves the n-th stream header buffer attached to the stream config
862 * event and stores it in @buf. Will store %NULL in @buf if there is no such
865 * Returns: TRUE if @event contained a stream header at @index and @buf has
866 * been set, otherwise FALSE.
869 gst_event_parse_nth_stream_config_header (GstEvent * event, guint index,
872 const GValue *val, *buf_val;
874 GstBuffer *ret = NULL;
876 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
877 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_CONFIG,
879 g_return_val_if_fail (buf != NULL, FALSE);
881 s = GST_EVENT_STRUCTURE (event);
882 val = gst_structure_id_get_value (s, GST_QUARK (STREAM_HEADERS));
885 buf_val = gst_value_array_get_value (val, index);
887 ret = g_value_get_boxed (buf_val);
891 return (ret != NULL);
895 * gst_event_new_segment:
896 * @segment: (transfer none): a #GstSegment
898 * Create a new SEGMENT event for @segment. The segment event can only travel
899 * downstream synchronized with the buffer flow and contains timing information
900 * and playback properties for the buffers that will follow.
902 * The newsegment event marks the range of buffers to be processed. All
903 * data not within the segment range is not to be processed. This can be
904 * used intelligently by plugins to apply more efficient methods of skipping
905 * unneeded data. The valid range is expressed with the @start and @stop
908 * The time value of the segment is used in conjunction with the start
909 * value to convert the buffer timestamps into the stream time. This is
910 * usually done in sinks to report the current stream_time.
911 * @time represents the stream_time of a buffer carrying a timestamp of
912 * @start. @time cannot be -1.
914 * @start cannot be -1, @stop can be -1. If there
915 * is a valid @stop given, it must be greater or equal the @start, including
916 * when the indicated playback @rate is < 0.
918 * The @applied_rate value provides information about any rate adjustment that
919 * has already been made to the timestamps and content on the buffers of the
920 * stream. (@rate * @applied_rate) should always equal the rate that has been
921 * requested for playback. For example, if an element has an input segment
922 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
923 * incoming timestamps and buffer content by half and output a newsegment event
924 * with @rate of 1.0 and @applied_rate of 2.0
926 * After a newsegment event, the buffer stream time is calculated with:
928 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
930 * Returns: (transfer full): the new SEGMENT event.
933 gst_event_new_segment (const GstSegment * segment)
937 g_return_val_if_fail (segment != NULL, NULL);
938 g_return_val_if_fail (segment->rate != 0.0, NULL);
939 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
940 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
942 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
945 event = gst_event_new_custom (GST_EVENT_SEGMENT,
946 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
947 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
953 * gst_event_parse_segment:
954 * @event: The event to parse
955 * @segment: (out) (transfer none): a pointer to a #GstSegment
957 * Parses a segment @event and stores the result in the given @segment location.
958 * @segment remains valid only until the @event is freed. Don't modify the segment
959 * and make a copy if you want to modify it or store it for later use.
962 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
964 GstStructure *structure;
966 g_return_if_fail (GST_IS_EVENT (event));
967 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
970 structure = GST_EVENT_STRUCTURE (event);
971 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
972 GST_QUARK (SEGMENT)));
977 * gst_event_copy_segment:
978 * @event: The event to parse
979 * @segment: a pointer to a #GstSegment
981 * Parses a segment @event and copies the #GstSegment into the location
985 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
987 const GstSegment *src;
989 g_return_if_fail (GST_IS_EVENT (event));
990 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
993 gst_event_parse_segment (event, &src);
994 gst_segment_copy_into (src, segment);
1000 * @name: (transfer none): the name of the event
1001 * @taglist: (transfer full): metadata list. The event will take ownership
1004 * Generates a metadata tag event from the given @taglist.
1006 * Since the TAG event has the %GST_EVENT_TYPE_STICKY_MULTI flag set, the
1007 * @name will be used to keep track of multiple tag events.
1009 * Returns: (transfer full): a new #GstEvent
1012 gst_event_new_tag (const gchar * name, GstTagList * taglist)
1015 GValue val = G_VALUE_INIT;
1017 g_return_val_if_fail (taglist != NULL, NULL);
1019 s = gst_structure_new_empty (name);
1020 g_value_init (&val, GST_TYPE_TAG_LIST);
1021 g_value_take_boxed (&val, taglist);
1022 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
1023 return gst_event_new_custom (GST_EVENT_TAG, s);
1027 * gst_event_parse_tag:
1028 * @event: a tag event
1029 * @taglist: (out) (transfer none): pointer to metadata list
1031 * Parses a tag @event and stores the results in the given @taglist location.
1032 * No reference to the taglist will be returned, it remains valid only until
1033 * the @event is freed. Don't modify or free the taglist, make a copy if you
1034 * want to modify it or store it for later use.
1037 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
1041 g_return_if_fail (GST_IS_EVENT (event));
1042 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
1044 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
1045 GST_QUARK (TAGLIST));
1048 *taglist = (GstTagList *) g_value_get_boxed (val);
1051 /* buffersize event */
1053 * gst_event_new_buffer_size:
1054 * @format: buffer format
1055 * @minsize: minimum buffer size
1056 * @maxsize: maximum buffer size
1057 * @async: thread behavior
1059 * Create a new buffersize event. The event is sent downstream and notifies
1060 * elements that they should provide a buffer of the specified dimensions.
1062 * When the @async flag is set, a thread boundary is preferred.
1064 * Returns: (transfer full): a new #GstEvent
1067 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
1068 gint64 maxsize, gboolean async)
1071 GstStructure *structure;
1073 GST_CAT_INFO (GST_CAT_EVENT,
1074 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
1075 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
1076 minsize, maxsize, async);
1078 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
1079 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1080 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
1081 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
1082 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
1083 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
1089 * gst_event_parse_buffer_size:
1090 * @event: The event to query
1091 * @format: (out): A pointer to store the format in
1092 * @minsize: (out): A pointer to store the minsize in
1093 * @maxsize: (out): A pointer to store the maxsize in
1094 * @async: (out): A pointer to store the async-flag in
1096 * Get the format, minsize, maxsize and async-flag in the buffersize event.
1099 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
1100 gint64 * minsize, gint64 * maxsize, gboolean * async)
1102 const GstStructure *structure;
1104 g_return_if_fail (GST_IS_EVENT (event));
1105 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1107 structure = GST_EVENT_STRUCTURE (event);
1109 *format = (GstFormat)
1110 g_value_get_enum (gst_structure_id_get_value (structure,
1111 GST_QUARK (FORMAT)));
1114 g_value_get_int64 (gst_structure_id_get_value (structure,
1115 GST_QUARK (MINSIZE)));
1118 g_value_get_int64 (gst_structure_id_get_value (structure,
1119 GST_QUARK (MAXSIZE)));
1122 g_value_get_boolean (gst_structure_id_get_value (structure,
1123 GST_QUARK (ASYNC)));
1127 * gst_event_new_qos:
1128 * @type: the QoS type
1129 * @proportion: the proportion of the qos message
1130 * @diff: The time difference of the last Clock sync
1131 * @timestamp: The timestamp of the buffer
1133 * Allocate a new qos event with the given values.
1134 * The QOS event is generated in an element that wants an upstream
1135 * element to either reduce or increase its rate because of
1136 * high/low CPU load or other resource usage such as network performance or
1137 * throttling. Typically sinks generate these events for each buffer
1140 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1141 * used when a buffer arrived in time or when the sink cannot keep up with
1142 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1143 * receiving buffers fast enough and thus has to drop late buffers.
1144 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1145 * by the application, for example to reduce power consumption.
1147 * @proportion indicates the real-time performance of the streaming in the
1148 * element that generated the QoS event (usually the sink). The value is
1149 * generally computed based on more long term statistics about the streams
1150 * timestamps compared to the clock.
1151 * A value < 1.0 indicates that the upstream element is producing data faster
1152 * than real-time. A value > 1.0 indicates that the upstream element is not
1153 * producing data fast enough. 1.0 is the ideal @proportion value. The
1154 * proportion value can safely be used to lower or increase the quality of
1157 * @diff is the difference against the clock in running time of the last
1158 * buffer that caused the element to generate the QOS event. A negative value
1159 * means that the buffer with @timestamp arrived in time. A positive value
1160 * indicates how late the buffer with @timestamp was. When throttling is
1161 * enabled, @diff will be set to the requested throttling interval.
1163 * @timestamp is the timestamp of the last buffer that cause the element
1164 * to generate the QOS event. It is expressed in running time and thus an ever
1167 * The upstream element can use the @diff and @timestamp values to decide
1168 * whether to process more buffers. For possitive @diff, all buffers with
1169 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1170 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1171 * result smaller than 0 is not allowed.
1173 * The application can use general event probes to intercept the QoS
1174 * event and implement custom application specific QoS handling.
1176 * Returns: (transfer full): a new QOS event.
1179 gst_event_new_qos (GstQOSType type, gdouble proportion,
1180 GstClockTimeDiff diff, GstClockTime timestamp)
1183 GstStructure *structure;
1185 /* diff must be positive or timestamp + diff must be positive */
1186 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1188 GST_CAT_LOG (GST_CAT_EVENT,
1189 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1190 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1191 diff, GST_TIME_ARGS (timestamp));
1193 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1194 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1195 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1196 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1197 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1198 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1204 * gst_event_parse_qos:
1205 * @event: The event to query
1206 * @type: (out): A pointer to store the QoS type in
1207 * @proportion: (out): A pointer to store the proportion in
1208 * @diff: (out): A pointer to store the diff in
1209 * @timestamp: (out): A pointer to store the timestamp in
1211 * Get the type, proportion, diff and timestamp in the qos event. See
1212 * gst_event_new_qos() for more information about the different QoS values.
1215 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1216 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1218 const GstStructure *structure;
1220 g_return_if_fail (GST_IS_EVENT (event));
1221 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1223 structure = GST_EVENT_STRUCTURE (event);
1225 *type = (GstQOSType)
1226 g_value_get_enum (gst_structure_id_get_value (structure,
1230 g_value_get_double (gst_structure_id_get_value (structure,
1231 GST_QUARK (PROPORTION)));
1234 g_value_get_int64 (gst_structure_id_get_value (structure,
1238 g_value_get_uint64 (gst_structure_id_get_value (structure,
1239 GST_QUARK (TIMESTAMP)));
1243 * gst_event_new_seek:
1244 * @rate: The new playback rate
1245 * @format: The format of the seek values
1246 * @flags: The optional seek flags
1247 * @start_type: The type and flags for the new start position
1248 * @start: The value of the new start position
1249 * @stop_type: The type and flags for the new stop position
1250 * @stop: The value of the new stop position
1252 * Allocate a new seek event with the given parameters.
1254 * The seek event configures playback of the pipeline between @start to @stop
1255 * at the speed given in @rate, also called a playback segment.
1256 * The @start and @stop values are expressed in @format.
1258 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1259 * Negatives values means backwards playback. A value of 0.0 for the
1260 * rate is not allowed and should be accomplished instead by PAUSING the
1263 * A pipeline has a default playback segment configured with a start
1264 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1265 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1267 * @start_type and @stop_type specify how to adjust the currently configured
1268 * start and stop fields in playback segment. Adjustments can be made relative
1269 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1270 * means that the position should not be updated.
1272 * When the rate is positive and @start has been updated, playback will start
1273 * from the newly configured start position.
1275 * For negative rates, playback will start from the newly configured stop
1276 * position (if any). If the stop position is updated, it must be different from
1277 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1279 * It is not possible to seek relative to the current playback position, to do
1280 * this, PAUSE the pipeline, query the current playback position with
1281 * #GST_QUERY_POSITION and update the playback segment current position with a
1282 * #GST_SEEK_TYPE_SET to the desired position.
1284 * Returns: (transfer full): a new seek event.
1287 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1288 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1291 GstStructure *structure;
1293 g_return_val_if_fail (rate != 0.0, NULL);
1295 if (format == GST_FORMAT_TIME) {
1296 GST_CAT_INFO (GST_CAT_EVENT,
1297 "creating seek rate %lf, format TIME, flags %d, "
1298 "start_type %d, start %" GST_TIME_FORMAT ", "
1299 "stop_type %d, stop %" GST_TIME_FORMAT,
1300 rate, flags, start_type, GST_TIME_ARGS (start),
1301 stop_type, GST_TIME_ARGS (stop));
1303 GST_CAT_INFO (GST_CAT_EVENT,
1304 "creating seek rate %lf, format %s, flags %d, "
1305 "start_type %d, start %" G_GINT64_FORMAT ", "
1306 "stop_type %d, stop %" G_GINT64_FORMAT,
1307 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1311 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1312 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1313 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1314 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1315 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1316 GST_QUARK (CUR), G_TYPE_INT64, start,
1317 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1318 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1319 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1325 * gst_event_parse_seek:
1326 * @event: a seek event
1327 * @rate: (out): result location for the rate
1328 * @format: (out): result location for the stream format
1329 * @flags: (out): result location for the #GstSeekFlags
1330 * @start_type: (out): result location for the #GstSeekType of the start position
1331 * @start: (out): result location for the start postion expressed in @format
1332 * @stop_type: (out): result location for the #GstSeekType of the stop position
1333 * @stop: (out): result location for the stop postion expressed in @format
1335 * Parses a seek @event and stores the results in the given result locations.
1338 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1339 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1340 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1342 const GstStructure *structure;
1344 g_return_if_fail (GST_IS_EVENT (event));
1345 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1347 structure = GST_EVENT_STRUCTURE (event);
1350 g_value_get_double (gst_structure_id_get_value (structure,
1353 *format = (GstFormat)
1354 g_value_get_enum (gst_structure_id_get_value (structure,
1355 GST_QUARK (FORMAT)));
1357 *flags = (GstSeekFlags)
1358 g_value_get_flags (gst_structure_id_get_value (structure,
1359 GST_QUARK (FLAGS)));
1361 *start_type = (GstSeekType)
1362 g_value_get_enum (gst_structure_id_get_value (structure,
1363 GST_QUARK (CUR_TYPE)));
1366 g_value_get_int64 (gst_structure_id_get_value (structure,
1369 *stop_type = (GstSeekType)
1370 g_value_get_enum (gst_structure_id_get_value (structure,
1371 GST_QUARK (STOP_TYPE)));
1374 g_value_get_int64 (gst_structure_id_get_value (structure,
1379 * gst_event_new_navigation:
1380 * @structure: (transfer full): description of the event. The event will take
1381 * ownership of the structure.
1383 * Create a new navigation event from the given description.
1385 * Returns: (transfer full): a new #GstEvent
1388 gst_event_new_navigation (GstStructure * structure)
1390 g_return_val_if_fail (structure != NULL, NULL);
1392 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1396 * gst_event_new_latency:
1397 * @latency: the new latency value
1399 * Create a new latency event. The event is sent upstream from the sinks and
1400 * notifies elements that they should add an additional @latency to the
1401 * running time before synchronising against the clock.
1403 * The latency is mostly used in live sinks and is always expressed in
1406 * Returns: (transfer full): a new #GstEvent
1411 gst_event_new_latency (GstClockTime latency)
1414 GstStructure *structure;
1416 GST_CAT_INFO (GST_CAT_EVENT,
1417 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1419 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1420 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1421 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1427 * gst_event_parse_latency:
1428 * @event: The event to query
1429 * @latency: (out): A pointer to store the latency in.
1431 * Get the latency in the latency event.
1436 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1438 g_return_if_fail (GST_IS_EVENT (event));
1439 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1443 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1444 (event), GST_QUARK (LATENCY)));
1448 * gst_event_new_step:
1449 * @format: the format of @amount
1450 * @amount: the amount of data to step
1451 * @rate: the step rate
1452 * @flush: flushing steps
1453 * @intermediate: intermediate steps
1455 * Create a new step event. The purpose of the step event is to instruct a sink
1456 * to skip @amount (expressed in @format) of media. It can be used to implement
1457 * stepping through the video frame by frame or for doing fast trick modes.
1459 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1460 * = 0.0 or first reverse the direction of playback using a seek event to get
1461 * the same effect as rate < 0.0.
1463 * The @flush flag will clear any pending data in the pipeline before starting
1464 * the step operation.
1466 * The @intermediate flag instructs the pipeline that this step operation is
1467 * part of a larger step operation.
1469 * Returns: (transfer full): a new #GstEvent
1474 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1475 gboolean flush, gboolean intermediate)
1478 GstStructure *structure;
1480 g_return_val_if_fail (rate > 0.0, NULL);
1482 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1484 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1485 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1486 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1487 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1488 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1489 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1490 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1496 * gst_event_parse_step:
1497 * @event: The event to query
1498 * @format: (out) (allow-none): a pointer to store the format in
1499 * @amount: (out) (allow-none): a pointer to store the amount in
1500 * @rate: (out) (allow-none): a pointer to store the rate in
1501 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1502 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1505 * Parse the step event.
1510 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1511 gdouble * rate, gboolean * flush, gboolean * intermediate)
1513 const GstStructure *structure;
1515 g_return_if_fail (GST_IS_EVENT (event));
1516 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1518 structure = GST_EVENT_STRUCTURE (event);
1521 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1522 GST_QUARK (FORMAT)));
1524 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1525 GST_QUARK (AMOUNT)));
1527 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1530 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1531 GST_QUARK (FLUSH)));
1533 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1534 GST_QUARK (INTERMEDIATE)));
1538 * gst_event_new_reconfigure:
1540 * Create a new reconfigure event. The purpose of the reconfingure event is
1541 * to travel upstream and make elements renegotiate their caps or reconfigure
1542 * their buffer pools. This is useful when changing properties on elements
1543 * or changing the topology of the pipeline.
1545 * Returns: (transfer full): a new #GstEvent
1550 gst_event_new_reconfigure (void)
1554 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1556 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1562 * gst_event_new_sink_message:
1563 * @name: a name for the event
1564 * @msg: (transfer none): the #GstMessage to be posted
1566 * Create a new sink-message event. The purpose of the sink-message event is
1567 * to instruct a sink to post the message contained in the event synchronized
1570 * @name is used to store multiple sticky events on one pad.
1572 * Returns: (transfer full): a new #GstEvent
1576 /* FIXME 0.11: take ownership of msg for consistency? */
1578 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1581 GstStructure *structure;
1583 g_return_val_if_fail (msg != NULL, NULL);
1585 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1587 structure = gst_structure_new_id (g_quark_from_string (name),
1588 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1589 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1595 * gst_event_parse_sink_message:
1596 * @event: The event to query
1597 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1599 * Parse the sink-message event. Unref @msg after usage.
1604 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1606 const GstStructure *structure;
1608 g_return_if_fail (GST_IS_EVENT (event));
1609 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1611 structure = GST_EVENT_STRUCTURE (event);
1614 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1615 (structure, GST_QUARK (MESSAGE))));
1619 * gst_event_new_stream_start
1621 * Create a new STREAM_START event. The stream start event can only
1622 * travel downstream synchronized with the buffer flow. It is expected
1623 * to be the first event that is sent for a new stream.
1625 * Source elements, demuxers and other elements that create new streams
1626 * are supposed to send this event as the first event of a new stream. It
1627 * should not be send after a flushing seek or in similar situations
1628 * and is used to mark the beginning of a new logical stream. Elements
1629 * combining multiple streams must ensure that this event is only forwarded
1630 * downstream once and not for every single input stream.
1632 * Returns: (transfer full): the new STREAM_START event.
1635 gst_event_new_stream_start (void)
1637 return gst_event_new_custom (GST_EVENT_STREAM_START, NULL);
1641 * gst_event_new_toc:
1642 * @name: a name for the event
1643 * @toc: #GstToc structure.
1644 * @updated: whether @toc was updated or not.
1646 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1647 * inform elements that some kind of the TOC was found.
1649 * Returns: a new #GstEvent.
1654 gst_event_new_toc (GstToc * toc, gboolean updated)
1656 GstStructure *toc_struct;
1658 g_return_val_if_fail (toc != NULL, NULL);
1660 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1662 toc_struct = __gst_toc_to_structure (toc);
1664 if (G_LIKELY (toc_struct != NULL)) {
1665 __gst_toc_structure_set_updated (toc_struct, updated);
1666 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1672 * gst_event_parse_toc:
1673 * @event: a TOC event.
1674 * @toc: (out): pointer to #GstToc structure.
1675 * @updated: (out): pointer to store TOC updated flag.
1677 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1682 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1684 const GstStructure *structure;
1686 g_return_if_fail (event != NULL);
1687 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1688 g_return_if_fail (toc != NULL);
1690 structure = gst_event_get_structure (event);
1691 *toc = __gst_toc_from_structure (structure);
1693 if (updated != NULL)
1694 *updated = __gst_toc_structure_get_updated (structure);
1698 * gst_event_new_toc_select:
1699 * @uid: UID in the TOC to start playback from.
1701 * Generate a TOC select event with the given @uid. The purpose of the
1702 * TOC select event is to start playback based on the TOC's entry with the
1705 * Returns: a new #GstEvent.
1710 gst_event_new_toc_select (const gchar * uid)
1712 GstStructure *structure;
1714 g_return_val_if_fail (uid != NULL, NULL);
1716 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1718 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1719 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1721 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1725 * gst_event_parse_toc_select:
1726 * @event: a TOC select event.
1727 * @uid: (out): storage for the selection UID.
1729 * Parse a TOC select @event and store the results in the given @uid location.
1734 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1736 const GstStructure *structure;
1739 g_return_if_fail (event != NULL);
1740 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1742 structure = gst_event_get_structure (event);
1743 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1746 *uid = g_strdup (g_value_get_string (val));