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 static 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_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_STICKY_SHIFT) - 1);
218 gst_event_get_type (void)
220 if (G_UNLIKELY (_gst_event_type == 0)) {
221 _gst_event_type = gst_mini_object_register ("GstEvent");
223 return _gst_event_type;
227 _gst_event_free (GstEvent * event)
231 g_return_if_fail (event != NULL);
232 g_return_if_fail (GST_IS_EVENT (event));
234 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
235 GST_EVENT_TYPE_NAME (event));
237 s = GST_EVENT_STRUCTURE (event);
240 gst_structure_set_parent_refcount (s, NULL);
241 gst_structure_free (s);
244 g_slice_free1 (GST_MINI_OBJECT_SIZE (event), event);
248 _gst_event_copy (GstEventImpl * event)
253 copy = g_slice_dup (GstEventImpl, event);
254 gst_mini_object_init (GST_MINI_OBJECT_CAST (copy), _gst_event_type,
255 sizeof (GstEventImpl));
257 GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
258 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
259 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
261 s = GST_EVENT_STRUCTURE (event);
263 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
264 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
265 ©->event.mini_object.refcount);
267 return GST_EVENT_CAST (copy);
271 gst_event_init (GstEventImpl * event, gsize size, GstEventType type)
273 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type, size);
275 event->event.mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
276 event->event.mini_object.free = (GstMiniObjectFreeFunction) _gst_event_free;
278 GST_EVENT_TYPE (event) = type;
279 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
280 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
284 gst_event_new (GstEventType type)
288 event = g_slice_new0 (GstEventImpl);
290 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
291 gst_event_type_get_name (type), type);
293 gst_event_init (event, sizeof (GstEventImpl), type);
295 return GST_EVENT_CAST (event);
299 * gst_event_new_custom:
300 * @type: The type of the new event
301 * @structure: (transfer full): the structure for the event. The event will
302 * take ownership of the structure.
304 * Create a new custom-typed event. This can be used for anything not
305 * handled by other event-specific functions to pass an event to another
308 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
309 * assigning a free number and filling in the correct direction and
310 * serialization flags.
312 * New custom events can also be created by subclassing the event type if
315 * Returns: (transfer full): the new custom event.
318 gst_event_new_custom (GstEventType type, GstStructure * structure)
322 /* structure must not have a parent */
324 g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
326 event = gst_event_new (type);
328 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
329 GST_EVENT_STRUCTURE (event) = structure;
335 * gst_event_get_structure:
336 * @event: The #GstEvent.
338 * Access the structure of the event.
340 * Returns: The structure of the event. The structure is still
341 * owned by the event, which means that you should not free it and
342 * that the pointer becomes invalid when you free the event.
347 gst_event_get_structure (GstEvent * event)
349 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
351 return GST_EVENT_STRUCTURE (event);
355 * gst_event_writable_structure:
356 * @event: The #GstEvent.
358 * Get a writable version of the structure.
360 * Returns: The structure of the event. The structure is still
361 * owned by the event, which means that you should not free it and
362 * that the pointer becomes invalid when you free the event.
363 * This function checks if @event is writable and will never return NULL.
368 gst_event_writable_structure (GstEvent * event)
370 GstStructure *structure;
372 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
373 g_return_val_if_fail (gst_event_is_writable (event), NULL);
375 structure = GST_EVENT_STRUCTURE (event);
377 if (structure == NULL) {
379 gst_structure_id_empty_new (gst_event_type_to_quark (GST_EVENT_TYPE
381 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
382 GST_EVENT_STRUCTURE (event) = structure;
388 * gst_event_has_name:
389 * @event: The #GstEvent.
390 * @name: name to check
392 * Checks if @event has the given @name. This function is usually used to
393 * check the name of a custom event.
395 * Returns: %TRUE if @name matches the name of the event structure.
400 gst_event_has_name (GstEvent * event, const gchar * name)
402 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
404 if (GST_EVENT_STRUCTURE (event) == NULL)
407 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
411 * gst_event_get_seqnum:
412 * @event: A #GstEvent.
414 * Retrieve the sequence number of a event.
416 * Events have ever-incrementing sequence numbers, which may also be set
417 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
418 * indicate that a event corresponds to some other set of events or messages,
419 * for example an EOS event corresponding to a SEEK event. It is considered good
420 * practice to make this correspondence when possible, though it is not
423 * Note that events and messages share the same sequence number incrementor;
424 * two events or messages will never not have the same sequence number unless
425 * that correspondence was made explicitly.
427 * Returns: The event's sequence number.
434 gst_event_get_seqnum (GstEvent * event)
436 g_return_val_if_fail (GST_IS_EVENT (event), -1);
438 return GST_EVENT_SEQNUM (event);
442 * gst_event_set_seqnum:
443 * @event: A #GstEvent.
444 * @seqnum: A sequence number.
446 * Set the sequence number of a event.
448 * This function might be called by the creator of a event to indicate that the
449 * event relates to other events or messages. See gst_event_get_seqnum() for
457 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
459 g_return_if_fail (GST_IS_EVENT (event));
461 GST_EVENT_SEQNUM (event) = seqnum;
464 /* FIXME 0.11: It would be nice to have flush events
465 * that don't reset the running time in the sinks
469 * gst_event_new_flush_start:
471 * Allocate a new flush start event. The flush start event can be sent
472 * upstream and downstream and travels out-of-bounds with the dataflow.
474 * It marks pads as being flushing and will make them return
475 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
476 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
477 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
478 * on a flushing pad will return %FALSE immediately.
480 * Elements should unlock any blocking functions and exit their streaming
481 * functions as fast as possible when this event is received.
483 * This event is typically generated after a seek to flush out all queued data
484 * in the pipeline so that the new media is played as soon as possible.
486 * Returns: (transfer full): a new flush start event.
489 gst_event_new_flush_start (void)
491 return gst_event_new (GST_EVENT_FLUSH_START);
495 * gst_event_new_flush_stop:
497 * Allocate a new flush stop event. The flush stop event can be sent
498 * upstream and downstream and travels serialized with the dataflow.
499 * It is typically sent after sending a FLUSH_START event to make the
500 * pads accept data again.
502 * Elements can process this event synchronized with the dataflow since
503 * the preceeding FLUSH_START event stopped the dataflow.
505 * This event is typically generated to complete a seek and to resume
508 * Returns: (transfer full): a new flush stop event.
511 gst_event_new_flush_stop (void)
513 return gst_event_new (GST_EVENT_FLUSH_STOP);
519 * Create a new EOS event. The eos event can only travel downstream
520 * synchronized with the buffer flow. Elements that receive the EOS
521 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
522 * when data after the EOS event arrives.
524 * The EOS event will travel down to the sink elements in the pipeline
525 * which will then post the #GST_MESSAGE_EOS on the bus after they have
526 * finished playing any buffered data.
528 * When all sinks have posted an EOS message, an EOS message is
529 * forwarded to the application.
531 * The EOS event itself will not cause any state transitions of the pipeline.
533 * Returns: (transfer full): the new EOS event.
536 gst_event_new_eos (void)
538 return gst_event_new (GST_EVENT_EOS);
542 * gst_event_new_caps:
545 * Create a new CAPS event for @caps. The caps event can only travel downstream
546 * synchronized with the buffer flow and contain the format of the buffers
547 * that will follow after the event.
549 * Returns: (transfer full): the new CAPS event.
552 gst_event_new_caps (GstCaps * caps)
556 g_return_val_if_fail (caps != NULL && gst_caps_is_fixed (caps), NULL);
558 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
560 event = gst_event_new_custom (GST_EVENT_CAPS,
561 gst_structure_id_new (GST_QUARK (EVENT_CAPS),
562 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
568 * gst_event_parse_caps:
569 * @event: The event to parse
570 * @caps: (out): A pointer to the caps
572 * Get the caps from @event. The caps remains valid as long as @event remains
576 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
578 GstStructure *structure;
580 g_return_if_fail (GST_IS_EVENT (event));
581 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
583 structure = GST_EVENT_STRUCTURE (event);
586 g_value_get_boxed (gst_structure_id_get_value (structure,
591 * gst_event_new_new_segment:
592 * @update: Whether this segment is an update to a previous one
593 * @rate: A new rate for playback
594 * @applied_rate: The rate factor which has already been applied
595 * @format: The format of the segment values
596 * @start: The start value of the segment
597 * @stop: The stop value of the segment
598 * @time: the time value of the segment
600 * Allocate a new newsegment event with the given format/values triplets.
602 * The newsegment event marks the range of buffers to be processed. All
603 * data not within the segment range is not to be processed. This can be
604 * used intelligently by plugins to apply more efficient methods of skipping
605 * unneeded data. The valid range is expressed with the @start and @stop
608 * The time value of the segment is used in conjunction with the start
609 * value to convert the buffer timestamps into the stream time. This is
610 * usually done in sinks to report the current stream_time.
611 * @time represents the stream_time of a buffer carrying a timestamp of
612 * @start. @time cannot be -1.
614 * @start cannot be -1, @stop can be -1. If there
615 * is a valid @stop given, it must be greater or equal the @start, including
616 * when the indicated playback @rate is < 0.
618 * The @applied_rate value provides information about any rate adjustment that
619 * has already been made to the timestamps and content on the buffers of the
620 * stream. (@rate * @applied_rate) should always equal the rate that has been
621 * requested for playback. For example, if an element has an input segment
622 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
623 * incoming timestamps and buffer content by half and output a newsegment event
624 * with @rate of 1.0 and @applied_rate of 2.0
626 * After a newsegment event, the buffer stream time is calculated with:
628 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
630 * Returns: (transfer full): a new newsegment event.
635 gst_event_new_new_segment (gboolean update, gdouble rate,
636 gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
640 GstStructure *structure;
642 g_return_val_if_fail (rate != 0.0, NULL);
643 g_return_val_if_fail (applied_rate != 0.0, NULL);
645 if (format == GST_FORMAT_TIME) {
646 GST_CAT_INFO (GST_CAT_EVENT,
647 "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
648 "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
649 ", time %" GST_TIME_FORMAT,
650 update, rate, GST_TIME_ARGS (start),
651 GST_TIME_ARGS (stop), GST_TIME_ARGS (time));
653 GST_CAT_INFO (GST_CAT_EVENT,
654 "creating newsegment update %d, rate %lf, format %s, "
655 "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", time %"
656 G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
660 g_return_val_if_fail (time != -1, NULL);
661 g_return_val_if_fail (start != -1, NULL);
663 g_return_val_if_fail (start <= stop, NULL);
665 structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
666 GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
667 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
668 GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
669 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
670 GST_QUARK (START), G_TYPE_INT64, start,
671 GST_QUARK (STOP), G_TYPE_INT64, stop,
672 GST_QUARK (TIME), G_TYPE_INT64, time, NULL);
673 event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
679 * gst_event_parse_new_segment:
680 * @event: The event to query
681 * @update: (out): A pointer to the update flag of the segment
682 * @rate: (out): A pointer to the rate of the segment
683 * @applied_rate: (out): A pointer to the applied_rate of the segment
684 * @format: (out): A pointer to the format of the newsegment values
685 * @start: (out): A pointer to store the start value in
686 * @stop: (out): A pointer to store the stop value in
687 * @time: (out): A pointer to store the time value in
689 * Get the update, rate, applied_rate, format, start, stop and
690 * time in the newsegment event. See gst_event_new_new_segment()
691 * for a full description of the newsegment event.
696 gst_event_parse_new_segment (GstEvent * event, gboolean * update,
697 gdouble * rate, gdouble * applied_rate, GstFormat * format,
698 gint64 * start, gint64 * stop, gint64 * time)
700 const GstStructure *structure;
702 g_return_if_fail (GST_IS_EVENT (event));
703 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
705 structure = GST_EVENT_STRUCTURE (event);
706 if (G_LIKELY (update))
708 g_value_get_boolean (gst_structure_id_get_value (structure,
709 GST_QUARK (UPDATE)));
712 g_value_get_double (gst_structure_id_get_value (structure,
714 if (G_LIKELY (applied_rate))
716 g_value_get_double (gst_structure_id_get_value (structure,
717 GST_QUARK (APPLIED_RATE)));
718 if (G_LIKELY (format))
720 g_value_get_enum (gst_structure_id_get_value (structure,
721 GST_QUARK (FORMAT)));
722 if (G_LIKELY (start))
724 g_value_get_int64 (gst_structure_id_get_value (structure,
728 g_value_get_int64 (gst_structure_id_get_value (structure,
732 g_value_get_int64 (gst_structure_id_get_value (structure,
738 * @taglist: (transfer full): metadata list. The event will take ownership
741 * Generates a metadata tag event from the given @taglist.
743 * Returns: (transfer full): a new #GstEvent
746 gst_event_new_tag (GstTagList * taglist)
748 g_return_val_if_fail (taglist != NULL, NULL);
750 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
754 * gst_event_parse_tag:
755 * @event: a tag event
756 * @taglist: (out) (transfer none): pointer to metadata list
758 * Parses a tag @event and stores the results in the given @taglist location.
759 * No reference to the taglist will be returned, it remains valid only until
760 * the @event is freed. Don't modify or free the taglist, make a copy if you
761 * want to modify it or store it for later use.
764 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
766 g_return_if_fail (GST_IS_EVENT (event));
767 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
770 *taglist = (GstTagList *) GST_EVENT_STRUCTURE (event);
773 /* buffersize event */
775 * gst_event_new_buffer_size:
776 * @format: buffer format
777 * @minsize: minimum buffer size
778 * @maxsize: maximum buffer size
779 * @async: thread behavior
781 * Create a new buffersize event. The event is sent downstream and notifies
782 * elements that they should provide a buffer of the specified dimensions.
784 * When the @async flag is set, a thread boundary is prefered.
786 * Returns: (transfer full): a new #GstEvent
789 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
790 gint64 maxsize, gboolean async)
793 GstStructure *structure;
795 GST_CAT_INFO (GST_CAT_EVENT,
796 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
797 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
798 minsize, maxsize, async);
800 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
801 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
802 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
803 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
804 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
805 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
811 * gst_event_parse_buffer_size:
812 * @event: The event to query
813 * @format: (out): A pointer to store the format in
814 * @minsize: (out): A pointer to store the minsize in
815 * @maxsize: (out): A pointer to store the maxsize in
816 * @async: (out): A pointer to store the async-flag in
818 * Get the format, minsize, maxsize and async-flag in the buffersize event.
821 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
822 gint64 * minsize, gint64 * maxsize, gboolean * async)
824 const GstStructure *structure;
826 g_return_if_fail (GST_IS_EVENT (event));
827 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
829 structure = GST_EVENT_STRUCTURE (event);
832 g_value_get_enum (gst_structure_id_get_value (structure,
833 GST_QUARK (FORMAT)));
836 g_value_get_int64 (gst_structure_id_get_value (structure,
837 GST_QUARK (MINSIZE)));
840 g_value_get_int64 (gst_structure_id_get_value (structure,
841 GST_QUARK (MAXSIZE)));
844 g_value_get_boolean (gst_structure_id_get_value (structure,
850 * @type: the QoS type
851 * @proportion: the proportion of the qos message
852 * @diff: The time difference of the last Clock sync
853 * @timestamp: The timestamp of the buffer
855 * Allocate a new qos event with the given values.
856 * The QOS event is generated in an element that wants an upstream
857 * element to either reduce or increase its rate because of
858 * high/low CPU load or other resource usage such as network performance or
859 * throttling. Typically sinks generate these events for each buffer
862 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
863 * used when a buffer arrived in time or when the sink cannot keep up with
864 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
865 * receiving buffers fast enough and thus has to drop late buffers.
866 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
867 * by the application, for example to reduce power consumption.
869 * @proportion indicates the real-time performance of the streaming in the
870 * element that generated the QoS event (usually the sink). The value is
871 * generally computed based on more long term statistics about the streams
872 * timestamps compared to the clock.
873 * A value < 1.0 indicates that the upstream element is producing data faster
874 * than real-time. A value > 1.0 indicates that the upstream element is not
875 * producing data fast enough. 1.0 is the ideal @proportion value. The
876 * proportion value can safely be used to lower or increase the quality of
879 * @diff is the difference against the clock in running time of the last
880 * buffer that caused the element to generate the QOS event. A negative value
881 * means that the buffer with @timestamp arrived in time. A positive value
882 * indicates how late the buffer with @timestamp was. When throttling is
883 * enabled, @diff will be set to the requested throttling interval.
885 * @timestamp is the timestamp of the last buffer that cause the element
886 * to generate the QOS event. It is expressed in running time and thus an ever
889 * The upstream element can use the @diff and @timestamp values to decide
890 * whether to process more buffers. For possitive @diff, all buffers with
891 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
892 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
893 * result smaller than 0 is not allowed.
895 * The application can use general event probes to intercept the QoS
896 * event and implement custom application specific QoS handling.
898 * Returns: (transfer full): a new QOS event.
901 gst_event_new_qos (GstQOSType type, gdouble proportion,
902 GstClockTimeDiff diff, GstClockTime timestamp)
906 /* diff must be positive or timestamp + diff must be positive */
907 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
909 GST_CAT_INFO (GST_CAT_EVENT,
910 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
911 ", timestamp %" GST_TIME_FORMAT, type, proportion,
912 diff, GST_TIME_ARGS (timestamp));
914 event = gst_event_new (GST_EVENT_QOS);
916 GST_EVENT_IMPL (event, qos, type) = type;
917 GST_EVENT_IMPL (event, qos, proportion) = proportion;
918 GST_EVENT_IMPL (event, qos, diff) = diff;
919 GST_EVENT_IMPL (event, qos, timestamp) = timestamp;
925 * gst_event_parse_qos:
926 * @event: The event to query
927 * @type: (out): A pointer to store the QoS type in
928 * @proportion: (out): A pointer to store the proportion in
929 * @diff: (out): A pointer to store the diff in
930 * @timestamp: (out): A pointer to store the timestamp in
932 * Get the type, proportion, diff and timestamp in the qos event. See
933 * gst_event_new_qos() for more information about the different QoS values.
936 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
937 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
939 g_return_if_fail (GST_IS_EVENT (event));
940 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
943 *type = GST_EVENT_IMPL (event, qos, type);
945 *proportion = GST_EVENT_IMPL (event, qos, proportion);
947 *diff = GST_EVENT_IMPL (event, qos, diff);
949 *timestamp = GST_EVENT_IMPL (event, qos, timestamp);
953 * gst_event_new_seek:
954 * @rate: The new playback rate
955 * @format: The format of the seek values
956 * @flags: The optional seek flags
957 * @start_type: The type and flags for the new start position
958 * @start: The value of the new start position
959 * @stop_type: The type and flags for the new stop position
960 * @stop: The value of the new stop position
962 * Allocate a new seek event with the given parameters.
964 * The seek event configures playback of the pipeline between @start to @stop
965 * at the speed given in @rate, also called a playback segment.
966 * The @start and @stop values are expressed in @format.
968 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
969 * Negatives values means backwards playback. A value of 0.0 for the
970 * rate is not allowed and should be accomplished instead by PAUSING the
973 * A pipeline has a default playback segment configured with a start
974 * position of 0, a stop position of -1 and a rate of 1.0. The currently
975 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
977 * @start_type and @stop_type specify how to adjust the currently configured
978 * start and stop fields in playback segment. Adjustments can be made relative
979 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
980 * means that the position should not be updated.
982 * When the rate is positive and @start has been updated, playback will start
983 * from the newly configured start position.
985 * For negative rates, playback will start from the newly configured stop
986 * position (if any). If the stop position if updated, it must be different from
987 * -1 for negative rates.
989 * It is not possible to seek relative to the current playback position, to do
990 * this, PAUSE the pipeline, query the current playback position with
991 * #GST_QUERY_POSITION and update the playback segment current position with a
992 * #GST_SEEK_TYPE_SET to the desired position.
994 * Returns: (transfer full): a new seek event.
997 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
998 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1001 GstStructure *structure;
1003 g_return_val_if_fail (rate != 0.0, NULL);
1005 if (format == GST_FORMAT_TIME) {
1006 GST_CAT_INFO (GST_CAT_EVENT,
1007 "creating seek rate %lf, format TIME, flags %d, "
1008 "start_type %d, start %" GST_TIME_FORMAT ", "
1009 "stop_type %d, stop %" GST_TIME_FORMAT,
1010 rate, flags, start_type, GST_TIME_ARGS (start),
1011 stop_type, GST_TIME_ARGS (stop));
1013 GST_CAT_INFO (GST_CAT_EVENT,
1014 "creating seek rate %lf, format %s, flags %d, "
1015 "start_type %d, start %" G_GINT64_FORMAT ", "
1016 "stop_type %d, stop %" G_GINT64_FORMAT,
1017 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1021 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1022 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1023 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1024 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1025 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1026 GST_QUARK (CUR), G_TYPE_INT64, start,
1027 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1028 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1029 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1035 * gst_event_parse_seek:
1036 * @event: a seek event
1037 * @rate: (out): result location for the rate
1038 * @format: (out): result location for the stream format
1039 * @flags: (out): result location for the #GstSeekFlags
1040 * @start_type: (out): result location for the #GstSeekType of the start position
1041 * @start: (out): result location for the start postion expressed in @format
1042 * @stop_type: (out): result location for the #GstSeekType of the stop position
1043 * @stop: (out): result location for the stop postion expressed in @format
1045 * Parses a seek @event and stores the results in the given result locations.
1048 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1049 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1050 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1052 const GstStructure *structure;
1054 g_return_if_fail (GST_IS_EVENT (event));
1055 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1057 structure = GST_EVENT_STRUCTURE (event);
1060 g_value_get_double (gst_structure_id_get_value (structure,
1064 g_value_get_enum (gst_structure_id_get_value (structure,
1065 GST_QUARK (FORMAT)));
1068 g_value_get_flags (gst_structure_id_get_value (structure,
1069 GST_QUARK (FLAGS)));
1072 g_value_get_enum (gst_structure_id_get_value (structure,
1073 GST_QUARK (CUR_TYPE)));
1076 g_value_get_int64 (gst_structure_id_get_value (structure,
1080 g_value_get_enum (gst_structure_id_get_value (structure,
1081 GST_QUARK (STOP_TYPE)));
1084 g_value_get_int64 (gst_structure_id_get_value (structure,
1089 * gst_event_new_navigation:
1090 * @structure: (transfer full): description of the event. The event will take
1091 * ownership of the structure.
1093 * Create a new navigation event from the given description.
1095 * Returns: (transfer full): a new #GstEvent
1098 gst_event_new_navigation (GstStructure * structure)
1100 g_return_val_if_fail (structure != NULL, NULL);
1102 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1106 * gst_event_new_latency:
1107 * @latency: the new latency value
1109 * Create a new latency event. The event is sent upstream from the sinks and
1110 * notifies elements that they should add an additional @latency to the
1111 * running time before synchronising against the clock.
1113 * The latency is mostly used in live sinks and is always expressed in
1116 * Returns: (transfer full): a new #GstEvent
1121 gst_event_new_latency (GstClockTime latency)
1124 GstStructure *structure;
1126 GST_CAT_INFO (GST_CAT_EVENT,
1127 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1129 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1130 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1131 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1137 * gst_event_parse_latency:
1138 * @event: The event to query
1139 * @latency: (out): A pointer to store the latency in.
1141 * Get the latency in the latency event.
1146 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1148 g_return_if_fail (GST_IS_EVENT (event));
1149 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1153 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1154 (event), GST_QUARK (LATENCY)));
1158 * gst_event_new_step:
1159 * @format: the format of @amount
1160 * @amount: the amount of data to step
1161 * @rate: the step rate
1162 * @flush: flushing steps
1163 * @intermediate: intermediate steps
1165 * Create a new step event. The purpose of the step event is to instruct a sink
1166 * to skip @amount (expressed in @format) of media. It can be used to implement
1167 * stepping through the video frame by frame or for doing fast trick modes.
1169 * A rate of <= 0.0 is not allowed, pause the pipeline or reverse the playback
1170 * direction of the pipeline to get the same effect.
1172 * The @flush flag will clear any pending data in the pipeline before starting
1173 * the step operation.
1175 * The @intermediate flag instructs the pipeline that this step operation is
1176 * part of a larger step operation.
1178 * Returns: (transfer full): a new #GstEvent
1183 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1184 gboolean flush, gboolean intermediate)
1187 GstStructure *structure;
1189 g_return_val_if_fail (rate > 0.0, NULL);
1191 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1193 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1194 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1195 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1196 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1197 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1198 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1199 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1205 * gst_event_parse_step:
1206 * @event: The event to query
1207 * @format: (out) (allow-none): a pointer to store the format in
1208 * @amount: (out) (allow-none): a pointer to store the amount in
1209 * @rate: (out) (allow-none): a pointer to store the rate in
1210 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1211 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1214 * Parse the step event.
1219 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1220 gdouble * rate, gboolean * flush, gboolean * intermediate)
1222 const GstStructure *structure;
1224 g_return_if_fail (GST_IS_EVENT (event));
1225 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1227 structure = GST_EVENT_STRUCTURE (event);
1229 *format = g_value_get_enum (gst_structure_id_get_value (structure,
1230 GST_QUARK (FORMAT)));
1232 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1233 GST_QUARK (AMOUNT)));
1235 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1238 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1239 GST_QUARK (FLUSH)));
1241 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1242 GST_QUARK (INTERMEDIATE)));
1246 * gst_event_new_reconfigure:
1248 * Create a new reconfigure event. The purpose of the reconfingure event is
1249 * to travel upstream and make elements renegotiate their caps or reconfigure
1250 * their buffer pools. This is useful when changing properties on elements
1251 * or changing the topology of the pipeline.
1253 * Returns: (transfer full): a new #GstEvent
1258 gst_event_new_reconfigure (void)
1262 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1264 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1270 * gst_event_new_sink_message:
1271 * @msg: (transfer none): the #GstMessage to be posted
1273 * Create a new sink-message event. The purpose of the sink-message event is
1274 * to instruct a sink to post the message contained in the event synchronized
1277 * Returns: (transfer full): a new #GstEvent
1281 /* FIXME 0.11: take ownership of msg for consistency? */
1283 gst_event_new_sink_message (GstMessage * msg)
1286 GstStructure *structure;
1288 g_return_val_if_fail (msg != NULL, NULL);
1290 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1292 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1293 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1294 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1300 * gst_event_parse_sink_message:
1301 * @event: The event to query
1302 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1304 * Parse the sink-message event. Unref @msg after usage.
1309 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1311 const GstStructure *structure;
1313 g_return_if_fail (GST_IS_EVENT (event));
1314 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1316 structure = GST_EVENT_STRUCTURE (event);
1319 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1320 (structure, GST_QUARK (MESSAGE))));