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 specity 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 2006-09-6 (0.10.10)
79 #include "gst_private.h"
80 #include <string.h> /* memcpy */
84 #include "gstenumtypes.h"
88 GType _gst_event_type = 0;
95 GstClockTime timestamp;
102 GstStructure *structure;
110 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
111 #define GST_EVENT_IMPL(e,data,field) (((GstEventImpl *)(e))->data.field)
120 static GstEventQuarks event_quarks[] = {
121 {GST_EVENT_UNKNOWN, "unknown", 0},
122 {GST_EVENT_FLUSH_START, "flush-start", 0},
123 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
124 {GST_EVENT_EOS, "eos", 0},
125 {GST_EVENT_CAPS, "caps", 0},
126 {GST_EVENT_NEWSEGMENT, "newsegment", 0},
127 {GST_EVENT_TAG, "tag", 0},
128 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
129 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
130 {GST_EVENT_QOS, "qos", 0},
131 {GST_EVENT_SEEK, "seek", 0},
132 {GST_EVENT_NAVIGATION, "navigation", 0},
133 {GST_EVENT_LATENCY, "latency", 0},
134 {GST_EVENT_STEP, "step", 0},
135 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
136 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
137 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
138 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
139 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
140 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
146 _gst_event_initialize (void)
150 _gst_event_type = gst_mini_object_register ("GstEvent");
152 g_type_class_ref (gst_seek_flags_get_type ());
153 g_type_class_ref (gst_seek_type_get_type ());
155 for (i = 0; event_quarks[i].name; i++) {
156 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
161 * gst_event_type_get_name:
162 * @type: the event type
164 * Get a printable name for the given event type. Do not modify or free.
166 * Returns: a reference to the static name of the event.
169 gst_event_type_get_name (GstEventType type)
173 for (i = 0; event_quarks[i].name; i++) {
174 if (type == event_quarks[i].type)
175 return event_quarks[i].name;
181 * gst_event_type_to_quark:
182 * @type: the event type
184 * Get the unique quark for the given event type.
186 * Returns: the quark associated with the event type
189 gst_event_type_to_quark (GstEventType type)
193 for (i = 0; event_quarks[i].name; i++) {
194 if (type == event_quarks[i].type)
195 return event_quarks[i].quark;
201 * gst_event_type_get_flags:
202 * @type: a #GstEventType
204 * Gets the #GstEventTypeFlags associated with @type.
206 * Returns: a #GstEventTypeFlags.
209 gst_event_type_get_flags (GstEventType type)
211 GstEventTypeFlags ret;
213 ret = type & ((1 << GST_EVENT_STICKY_SHIFT) - 1);
219 _gst_event_free (GstEvent * event)
223 g_return_if_fail (event != NULL);
224 g_return_if_fail (GST_IS_EVENT (event));
226 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
227 GST_EVENT_TYPE_NAME (event));
229 s = GST_EVENT_STRUCTURE (event);
232 gst_structure_set_parent_refcount (s, NULL);
233 gst_structure_free (s);
236 g_slice_free1 (GST_MINI_OBJECT_SIZE (event), event);
240 _gst_event_copy (GstEventImpl * event)
245 copy = g_slice_dup (GstEventImpl, event);
246 gst_mini_object_init (GST_MINI_OBJECT_CAST (copy), _gst_event_type,
247 sizeof (GstEventImpl));
249 GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
250 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
251 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
253 s = GST_EVENT_STRUCTURE (event);
255 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
256 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
257 ©->event.mini_object.refcount);
259 return GST_EVENT_CAST (copy);
263 gst_event_init (GstEventImpl * event, gsize size, GstEventType type)
265 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type, size);
267 event->event.mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
268 event->event.mini_object.free = (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 ();
276 gst_event_new (GstEventType type)
280 event = g_slice_new0 (GstEventImpl);
282 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
283 gst_event_type_get_name (type), type);
285 gst_event_init (event, sizeof (GstEventImpl), type);
287 return GST_EVENT_CAST (event);
291 * gst_event_new_custom:
292 * @type: The type of the new event
293 * @structure: (transfer full): the structure for the event. The event will
294 * take ownership of the structure.
296 * Create a new custom-typed event. This can be used for anything not
297 * handled by other event-specific functions to pass an event to another
300 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
301 * assigning a free number and filling in the correct direction and
302 * serialization flags.
304 * New custom events can also be created by subclassing the event type if
307 * Returns: (transfer full): the new custom event.
310 gst_event_new_custom (GstEventType type, GstStructure * structure)
314 /* structure must not have a parent */
316 g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
318 event = gst_event_new (type);
320 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
321 GST_EVENT_STRUCTURE (event) = structure;
326 static inline GstStructure *
327 add_structure (GstEvent * event, GQuark name)
329 GstStructure *structure;
331 structure = gst_structure_id_empty_new (name);
332 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
333 /* FIXME, concurrent access can make us leak this */
334 GST_EVENT_STRUCTURE (event) = structure;
339 static GstStructure *
340 update_structure (GstEvent * event)
342 GstStructure *structure;
344 structure = GST_EVENT_STRUCTURE (event);
345 switch (GST_EVENT_TYPE (event)) {
348 if (structure == NULL)
349 structure = add_structure (event, GST_QUARK (EVENT_QOS));
351 gst_structure_id_set (structure,
352 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, GST_EVENT_IMPL (event, qos,
353 type), GST_QUARK (PROPORTION), G_TYPE_DOUBLE,
354 GST_EVENT_IMPL (event, qos, proportion), GST_QUARK (DIFF),
355 G_TYPE_INT64, GST_EVENT_IMPL (event, qos, diff),
356 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, GST_EVENT_IMPL (event, qos,
367 * gst_event_get_structure:
368 * @event: The #GstEvent.
370 * Access the structure of the event.
372 * Returns: The structure of the event. The structure is still
373 * owned by the event, which means that you should not free it and
374 * that the pointer becomes invalid when you free the event.
379 gst_event_get_structure (GstEvent * event)
381 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
383 return update_structure (event);
387 * gst_event_writable_structure:
388 * @event: The #GstEvent.
390 * Get a writable version of the structure.
392 * Returns: The structure of the event. The structure is still
393 * owned by the event, which means that you should not free it and
394 * that the pointer becomes invalid when you free the event.
395 * This function checks if @event is writable and will never return NULL.
400 gst_event_writable_structure (GstEvent * event)
402 GstStructure *structure;
404 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
405 g_return_val_if_fail (gst_event_is_writable (event), NULL);
407 structure = update_structure (event);
409 if (structure == NULL)
411 add_structure (event, gst_event_type_to_quark (GST_EVENT_TYPE (event)));
417 * gst_event_has_name:
418 * @event: The #GstEvent.
419 * @name: name to check
421 * Checks if @event has the given @name. This function is usually used to
422 * check the name of a custom event.
424 * Returns: %TRUE if @name matches the name of the event structure.
429 gst_event_has_name (GstEvent * event, const gchar * name)
431 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
433 if (GST_EVENT_STRUCTURE (event) == NULL)
436 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
440 * gst_event_get_seqnum:
441 * @event: A #GstEvent.
443 * Retrieve the sequence number of a event.
445 * Events have ever-incrementing sequence numbers, which may also be set
446 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
447 * indicate that a event corresponds to some other set of events or messages,
448 * for example an EOS event corresponding to a SEEK event. It is considered good
449 * practice to make this correspondence when possible, though it is not
452 * Note that events and messages share the same sequence number incrementor;
453 * two events or messages will never not have the same sequence number unless
454 * that correspondence was made explicitly.
456 * Returns: The event's sequence number.
463 gst_event_get_seqnum (GstEvent * event)
465 g_return_val_if_fail (GST_IS_EVENT (event), -1);
467 return GST_EVENT_SEQNUM (event);
471 * gst_event_set_seqnum:
472 * @event: A #GstEvent.
473 * @seqnum: A sequence number.
475 * Set the sequence number of a event.
477 * This function might be called by the creator of a event to indicate that the
478 * event relates to other events or messages. See gst_event_get_seqnum() for
486 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
488 g_return_if_fail (GST_IS_EVENT (event));
490 GST_EVENT_SEQNUM (event) = seqnum;
493 /* FIXME 0.11: It would be nice to have flush events
494 * that don't reset the running time in the sinks
498 * gst_event_new_flush_start:
500 * Allocate a new flush start event. The flush start event can be sent
501 * upstream and downstream and travels out-of-bounds with the dataflow.
503 * It marks pads as being flushing and will make them return
504 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
505 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
506 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
507 * on a flushing pad will return %FALSE immediately.
509 * Elements should unlock any blocking functions and exit their streaming
510 * functions as fast as possible when this event is received.
512 * This event is typically generated after a seek to flush out all queued data
513 * in the pipeline so that the new media is played as soon as possible.
515 * Returns: (transfer full): a new flush start event.
518 gst_event_new_flush_start (void)
520 return gst_event_new (GST_EVENT_FLUSH_START);
524 * gst_event_new_flush_stop:
526 * Allocate a new flush stop event. The flush stop event can be sent
527 * upstream and downstream and travels serialized with the dataflow.
528 * It is typically sent after sending a FLUSH_START event to make the
529 * pads accept data again.
531 * Elements can process this event synchronized with the dataflow since
532 * the preceeding FLUSH_START event stopped the dataflow.
534 * This event is typically generated to complete a seek and to resume
537 * Returns: (transfer full): a new flush stop event.
540 gst_event_new_flush_stop (void)
542 return gst_event_new (GST_EVENT_FLUSH_STOP);
548 * Create a new EOS event. The eos event can only travel downstream
549 * synchronized with the buffer flow. Elements that receive the EOS
550 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
551 * when data after the EOS event arrives.
553 * The EOS event will travel down to the sink elements in the pipeline
554 * which will then post the #GST_MESSAGE_EOS on the bus after they have
555 * finished playing any buffered data.
557 * When all sinks have posted an EOS message, an EOS message is
558 * forwarded to the application.
560 * The EOS event itself will not cause any state transitions of the pipeline.
562 * Returns: (transfer full): the new EOS event.
565 gst_event_new_eos (void)
567 return gst_event_new (GST_EVENT_EOS);
571 * gst_event_new_caps:
574 * Create a new CAPS event for @caps. The caps event can only travel downstream
575 * synchronized with the buffer flow and contain the format of the buffers
576 * that will follow after the event.
578 * Returns: (transfer full): the new CAPS event.
581 gst_event_new_caps (GstCaps * caps)
585 g_return_val_if_fail (caps != NULL && gst_caps_is_fixed (caps), NULL);
587 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
589 event = gst_event_new_custom (GST_EVENT_CAPS,
590 gst_structure_id_new (GST_QUARK (EVENT_CAPS),
591 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
597 * gst_event_parse_caps:
598 * @event: The event to parse
599 * @caps: (out): A pointer to the caps
601 * Get the caps from @event. The caps remains valid as long as @event remains
605 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
607 GstStructure *structure;
609 g_return_if_fail (GST_IS_EVENT (event));
610 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
612 structure = GST_EVENT_STRUCTURE (event);
615 g_value_get_boxed (gst_structure_id_get_value (structure,
620 * gst_event_new_new_segment:
621 * @update: Whether this segment is an update to a previous one
622 * @rate: A new rate for playback
623 * @applied_rate: The rate factor which has already been applied
624 * @format: The format of the segment values
625 * @start: The start value of the segment
626 * @stop: The stop value of the segment
627 * @time: the time value of the segment
629 * Allocate a new newsegment event with the given format/values triplets.
631 * The newsegment event marks the range of buffers to be processed. All
632 * data not within the segment range is not to be processed. This can be
633 * used intelligently by plugins to apply more efficient methods of skipping
634 * unneeded data. The valid range is expressed with the @start and @stop
637 * The time value of the segment is used in conjunction with the start
638 * value to convert the buffer timestamps into the stream time. This is
639 * usually done in sinks to report the current stream_time.
640 * @time represents the stream_time of a buffer carrying a timestamp of
641 * @start. @time cannot be -1.
643 * @start cannot be -1, @stop can be -1. If there
644 * is a valid @stop given, it must be greater or equal the @start, including
645 * when the indicated playback @rate is < 0.
647 * The @applied_rate value provides information about any rate adjustment that
648 * has already been made to the timestamps and content on the buffers of the
649 * stream. (@rate * @applied_rate) should always equal the rate that has been
650 * requested for playback. For example, if an element has an input segment
651 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
652 * incoming timestamps and buffer content by half and output a newsegment event
653 * with @rate of 1.0 and @applied_rate of 2.0
655 * After a newsegment event, the buffer stream time is calculated with:
657 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
659 * Returns: (transfer full): a new newsegment event.
664 gst_event_new_new_segment (gboolean update, gdouble rate,
665 gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
669 GstStructure *structure;
671 g_return_val_if_fail (rate != 0.0, NULL);
672 g_return_val_if_fail (applied_rate != 0.0, NULL);
674 if (format == GST_FORMAT_TIME) {
675 GST_CAT_INFO (GST_CAT_EVENT,
676 "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
677 "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
678 ", time %" GST_TIME_FORMAT,
679 update, rate, GST_TIME_ARGS (start),
680 GST_TIME_ARGS (stop), GST_TIME_ARGS (time));
682 GST_CAT_INFO (GST_CAT_EVENT,
683 "creating newsegment update %d, rate %lf, format %s, "
684 "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", time %"
685 G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
689 g_return_val_if_fail (time != -1, NULL);
690 g_return_val_if_fail (start != -1, NULL);
692 g_return_val_if_fail (start <= stop, NULL);
694 structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
695 GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
696 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
697 GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
698 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
699 GST_QUARK (START), G_TYPE_INT64, start,
700 GST_QUARK (STOP), G_TYPE_INT64, stop,
701 GST_QUARK (TIME), G_TYPE_INT64, time, NULL);
702 event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
708 * gst_event_parse_new_segment:
709 * @event: The event to query
710 * @update: (out): A pointer to the update flag of the segment
711 * @rate: (out): A pointer to the rate of the segment
712 * @applied_rate: (out): A pointer to the applied_rate of the segment
713 * @format: (out): A pointer to the format of the newsegment values
714 * @start: (out): A pointer to store the start value in
715 * @stop: (out): A pointer to store the stop value in
716 * @time: (out): A pointer to store the time value in
718 * Get the update, rate, applied_rate, format, start, stop and
719 * time in the newsegment event. See gst_event_new_new_segment()
720 * for a full description of the newsegment event.
725 gst_event_parse_new_segment (GstEvent * event, gboolean * update,
726 gdouble * rate, gdouble * applied_rate, GstFormat * format,
727 gint64 * start, gint64 * stop, gint64 * time)
729 const GstStructure *structure;
731 g_return_if_fail (GST_IS_EVENT (event));
732 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
734 structure = GST_EVENT_STRUCTURE (event);
735 if (G_LIKELY (update))
737 g_value_get_boolean (gst_structure_id_get_value (structure,
738 GST_QUARK (UPDATE)));
741 g_value_get_double (gst_structure_id_get_value (structure,
743 if (G_LIKELY (applied_rate))
745 g_value_get_double (gst_structure_id_get_value (structure,
746 GST_QUARK (APPLIED_RATE)));
747 if (G_LIKELY (format))
749 g_value_get_enum (gst_structure_id_get_value (structure,
750 GST_QUARK (FORMAT)));
751 if (G_LIKELY (start))
753 g_value_get_int64 (gst_structure_id_get_value (structure,
757 g_value_get_int64 (gst_structure_id_get_value (structure,
761 g_value_get_int64 (gst_structure_id_get_value (structure,
767 * @taglist: (transfer full): metadata list. The event will take ownership
770 * Generates a metadata tag event from the given @taglist.
772 * Returns: (transfer full): a new #GstEvent
775 gst_event_new_tag (GstTagList * taglist)
777 g_return_val_if_fail (taglist != NULL, NULL);
779 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
783 * gst_event_parse_tag:
784 * @event: a tag event
785 * @taglist: (out) (transfer none): pointer to metadata list
787 * Parses a tag @event and stores the results in the given @taglist location.
788 * No reference to the taglist will be returned, it remains valid only until
789 * the @event is freed. Don't modify or free the taglist, make a copy if you
790 * want to modify it or store it for later use.
793 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
795 g_return_if_fail (GST_IS_EVENT (event));
796 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
799 *taglist = (GstTagList *) GST_EVENT_STRUCTURE (event);
802 /* buffersize event */
804 * gst_event_new_buffer_size:
805 * @format: buffer format
806 * @minsize: minimum buffer size
807 * @maxsize: maximum buffer size
808 * @async: thread behavior
810 * Create a new buffersize event. The event is sent downstream and notifies
811 * elements that they should provide a buffer of the specified dimensions.
813 * When the @async flag is set, a thread boundary is prefered.
815 * Returns: (transfer full): a new #GstEvent
818 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
819 gint64 maxsize, gboolean async)
822 GstStructure *structure;
824 GST_CAT_INFO (GST_CAT_EVENT,
825 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
826 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
827 minsize, maxsize, async);
829 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
830 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
831 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
832 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
833 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
834 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
840 * gst_event_parse_buffer_size:
841 * @event: The event to query
842 * @format: (out): A pointer to store the format in
843 * @minsize: (out): A pointer to store the minsize in
844 * @maxsize: (out): A pointer to store the maxsize in
845 * @async: (out): A pointer to store the async-flag in
847 * Get the format, minsize, maxsize and async-flag in the buffersize event.
850 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
851 gint64 * minsize, gint64 * maxsize, gboolean * async)
853 const GstStructure *structure;
855 g_return_if_fail (GST_IS_EVENT (event));
856 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
858 structure = GST_EVENT_STRUCTURE (event);
861 g_value_get_enum (gst_structure_id_get_value (structure,
862 GST_QUARK (FORMAT)));
865 g_value_get_int64 (gst_structure_id_get_value (structure,
866 GST_QUARK (MINSIZE)));
869 g_value_get_int64 (gst_structure_id_get_value (structure,
870 GST_QUARK (MAXSIZE)));
873 g_value_get_boolean (gst_structure_id_get_value (structure,
879 * @type: the QoS type
880 * @proportion: the proportion of the qos message
881 * @diff: The time difference of the last Clock sync
882 * @timestamp: The timestamp of the buffer
884 * Allocate a new qos event with the given values.
885 * The QOS event is generated in an element that wants an upstream
886 * element to either reduce or increase its rate because of
887 * high/low CPU load or other resource usage such as network performance or
888 * throttling. Typically sinks generate these events for each buffer
891 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
892 * used when a buffer arrived in time or when the sink cannot keep up with
893 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
894 * receiving buffers fast enough and thus has to drop late buffers.
895 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
896 * by the application, for example to reduce power consumption.
898 * @proportion indicates the real-time performance of the streaming in the
899 * element that generated the QoS event (usually the sink). The value is
900 * generally computed based on more long term statistics about the streams
901 * timestamps compared to the clock.
902 * A value < 1.0 indicates that the upstream element is producing data faster
903 * than real-time. A value > 1.0 indicates that the upstream element is not
904 * producing data fast enough. 1.0 is the ideal @proportion value. The
905 * proportion value can safely be used to lower or increase the quality of
908 * @diff is the difference against the clock in running time of the last
909 * buffer that caused the element to generate the QOS event. A negative value
910 * means that the buffer with @timestamp arrived in time. A positive value
911 * indicates how late the buffer with @timestamp was. When throttling is
912 * enabled, @diff will be set to the requested throttling interval.
914 * @timestamp is the timestamp of the last buffer that cause the element
915 * to generate the QOS event. It is expressed in running time and thus an ever
918 * The upstream element can use the @diff and @timestamp values to decide
919 * whether to process more buffers. For possitive @diff, all buffers with
920 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
921 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
922 * result smaller than 0 is not allowed.
924 * The application can use general event probes to intercept the QoS
925 * event and implement custom application specific QoS handling.
927 * Returns: (transfer full): a new QOS event.
930 gst_event_new_qos (GstQOSType type, gdouble proportion,
931 GstClockTimeDiff diff, GstClockTime timestamp)
935 /* diff must be positive or timestamp + diff must be positive */
936 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
938 GST_CAT_INFO (GST_CAT_EVENT,
939 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
940 ", timestamp %" GST_TIME_FORMAT, type, proportion,
941 diff, GST_TIME_ARGS (timestamp));
943 event = gst_event_new (GST_EVENT_QOS);
945 GST_EVENT_IMPL (event, qos, type) = type;
946 GST_EVENT_IMPL (event, qos, proportion) = proportion;
947 GST_EVENT_IMPL (event, qos, diff) = diff;
948 GST_EVENT_IMPL (event, qos, timestamp) = timestamp;
954 * gst_event_parse_qos:
955 * @event: The event to query
956 * @type: (out): A pointer to store the QoS type in
957 * @proportion: (out): A pointer to store the proportion in
958 * @diff: (out): A pointer to store the diff in
959 * @timestamp: (out): A pointer to store the timestamp in
961 * Get the type, proportion, diff and timestamp in the qos event. See
962 * gst_event_new_qos() for more information about the different QoS values.
965 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
966 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
968 g_return_if_fail (GST_IS_EVENT (event));
969 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
972 *type = GST_EVENT_IMPL (event, qos, type);
974 *proportion = GST_EVENT_IMPL (event, qos, proportion);
976 *diff = GST_EVENT_IMPL (event, qos, diff);
978 *timestamp = GST_EVENT_IMPL (event, qos, timestamp);
982 * gst_event_new_seek:
983 * @rate: The new playback rate
984 * @format: The format of the seek values
985 * @flags: The optional seek flags
986 * @start_type: The type and flags for the new start position
987 * @start: The value of the new start position
988 * @stop_type: The type and flags for the new stop position
989 * @stop: The value of the new stop position
991 * Allocate a new seek event with the given parameters.
993 * The seek event configures playback of the pipeline between @start to @stop
994 * at the speed given in @rate, also called a playback segment.
995 * The @start and @stop values are expressed in @format.
997 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
998 * Negatives values means backwards playback. A value of 0.0 for the
999 * rate is not allowed and should be accomplished instead by PAUSING the
1002 * A pipeline has a default playback segment configured with a start
1003 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1004 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1006 * @start_type and @stop_type specify how to adjust the currently configured
1007 * start and stop fields in playback segment. Adjustments can be made relative
1008 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1009 * means that the position should not be updated.
1011 * When the rate is positive and @start has been updated, playback will start
1012 * from the newly configured start position.
1014 * For negative rates, playback will start from the newly configured stop
1015 * position (if any). If the stop position if updated, it must be different from
1016 * -1 for negative rates.
1018 * It is not possible to seek relative to the current playback position, to do
1019 * this, PAUSE the pipeline, query the current playback position with
1020 * #GST_QUERY_POSITION and update the playback segment current position with a
1021 * #GST_SEEK_TYPE_SET to the desired position.
1023 * Returns: (transfer full): a new seek event.
1026 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1027 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1030 GstStructure *structure;
1032 g_return_val_if_fail (rate != 0.0, NULL);
1034 if (format == GST_FORMAT_TIME) {
1035 GST_CAT_INFO (GST_CAT_EVENT,
1036 "creating seek rate %lf, format TIME, flags %d, "
1037 "start_type %d, start %" GST_TIME_FORMAT ", "
1038 "stop_type %d, stop %" GST_TIME_FORMAT,
1039 rate, flags, start_type, GST_TIME_ARGS (start),
1040 stop_type, GST_TIME_ARGS (stop));
1042 GST_CAT_INFO (GST_CAT_EVENT,
1043 "creating seek rate %lf, format %s, flags %d, "
1044 "start_type %d, start %" G_GINT64_FORMAT ", "
1045 "stop_type %d, stop %" G_GINT64_FORMAT,
1046 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1050 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1051 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1052 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1053 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1054 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1055 GST_QUARK (CUR), G_TYPE_INT64, start,
1056 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1057 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1058 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1064 * gst_event_parse_seek:
1065 * @event: a seek event
1066 * @rate: (out): result location for the rate
1067 * @format: (out): result location for the stream format
1068 * @flags: (out): result location for the #GstSeekFlags
1069 * @start_type: (out): result location for the #GstSeekType of the start position
1070 * @start: (out): result location for the start postion expressed in @format
1071 * @stop_type: (out): result location for the #GstSeekType of the stop position
1072 * @stop: (out): result location for the stop postion expressed in @format
1074 * Parses a seek @event and stores the results in the given result locations.
1077 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1078 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1079 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1081 const GstStructure *structure;
1083 g_return_if_fail (GST_IS_EVENT (event));
1084 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1086 structure = GST_EVENT_STRUCTURE (event);
1089 g_value_get_double (gst_structure_id_get_value (structure,
1093 g_value_get_enum (gst_structure_id_get_value (structure,
1094 GST_QUARK (FORMAT)));
1097 g_value_get_flags (gst_structure_id_get_value (structure,
1098 GST_QUARK (FLAGS)));
1101 g_value_get_enum (gst_structure_id_get_value (structure,
1102 GST_QUARK (CUR_TYPE)));
1105 g_value_get_int64 (gst_structure_id_get_value (structure,
1109 g_value_get_enum (gst_structure_id_get_value (structure,
1110 GST_QUARK (STOP_TYPE)));
1113 g_value_get_int64 (gst_structure_id_get_value (structure,
1118 * gst_event_new_navigation:
1119 * @structure: (transfer full): description of the event. The event will take
1120 * ownership of the structure.
1122 * Create a new navigation event from the given description.
1124 * Returns: (transfer full): a new #GstEvent
1127 gst_event_new_navigation (GstStructure * structure)
1129 g_return_val_if_fail (structure != NULL, NULL);
1131 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1135 * gst_event_new_latency:
1136 * @latency: the new latency value
1138 * Create a new latency event. The event is sent upstream from the sinks and
1139 * notifies elements that they should add an additional @latency to the
1140 * running time before synchronising against the clock.
1142 * The latency is mostly used in live sinks and is always expressed in
1145 * Returns: (transfer full): a new #GstEvent
1150 gst_event_new_latency (GstClockTime latency)
1153 GstStructure *structure;
1155 GST_CAT_INFO (GST_CAT_EVENT,
1156 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1158 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1159 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1160 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1166 * gst_event_parse_latency:
1167 * @event: The event to query
1168 * @latency: (out): A pointer to store the latency in.
1170 * Get the latency in the latency event.
1175 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1177 g_return_if_fail (GST_IS_EVENT (event));
1178 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1182 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1183 (event), GST_QUARK (LATENCY)));
1187 * gst_event_new_step:
1188 * @format: the format of @amount
1189 * @amount: the amount of data to step
1190 * @rate: the step rate
1191 * @flush: flushing steps
1192 * @intermediate: intermediate steps
1194 * Create a new step event. The purpose of the step event is to instruct a sink
1195 * to skip @amount (expressed in @format) of media. It can be used to implement
1196 * stepping through the video frame by frame or for doing fast trick modes.
1198 * A rate of <= 0.0 is not allowed, pause the pipeline or reverse the playback
1199 * direction of the pipeline to get the same effect.
1201 * The @flush flag will clear any pending data in the pipeline before starting
1202 * the step operation.
1204 * The @intermediate flag instructs the pipeline that this step operation is
1205 * part of a larger step operation.
1207 * Returns: (transfer full): a new #GstEvent
1212 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1213 gboolean flush, gboolean intermediate)
1216 GstStructure *structure;
1218 g_return_val_if_fail (rate > 0.0, NULL);
1220 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1222 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1223 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1224 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1225 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1226 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1227 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1228 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1234 * gst_event_parse_step:
1235 * @event: The event to query
1236 * @format: (out) (allow-none): a pointer to store the format in
1237 * @amount: (out) (allow-none): a pointer to store the amount in
1238 * @rate: (out) (allow-none): a pointer to store the rate in
1239 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1240 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1243 * Parse the step event.
1248 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1249 gdouble * rate, gboolean * flush, gboolean * intermediate)
1251 const GstStructure *structure;
1253 g_return_if_fail (GST_IS_EVENT (event));
1254 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1256 structure = GST_EVENT_STRUCTURE (event);
1258 *format = g_value_get_enum (gst_structure_id_get_value (structure,
1259 GST_QUARK (FORMAT)));
1261 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1262 GST_QUARK (AMOUNT)));
1264 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1267 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1268 GST_QUARK (FLUSH)));
1270 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1271 GST_QUARK (INTERMEDIATE)));
1275 * gst_event_new_reconfigure:
1277 * Create a new reconfigure event. The purpose of the reconfingure event is
1278 * to travel upstream and make elements renegotiate their caps or reconfigure
1279 * their buffer pools. This is useful when changing properties on elements
1280 * or changing the topology of the pipeline.
1282 * Returns: (transfer full): a new #GstEvent
1287 gst_event_new_reconfigure (void)
1291 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1293 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1299 * gst_event_new_sink_message:
1300 * @msg: (transfer none): the #GstMessage to be posted
1302 * Create a new sink-message event. The purpose of the sink-message event is
1303 * to instruct a sink to post the message contained in the event synchronized
1306 * Returns: (transfer full): a new #GstEvent
1310 /* FIXME 0.11: take ownership of msg for consistency? */
1312 gst_event_new_sink_message (GstMessage * msg)
1315 GstStructure *structure;
1317 g_return_val_if_fail (msg != NULL, NULL);
1319 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1321 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1322 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1323 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1329 * gst_event_parse_sink_message:
1330 * @event: The event to query
1331 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1333 * Parse the sink-message event. Unref @msg after usage.
1338 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1340 const GstStructure *structure;
1342 g_return_if_fail (GST_IS_EVENT (event));
1343 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1345 structure = GST_EVENT_STRUCTURE (event);
1348 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1349 (structure, GST_QUARK (MESSAGE))));