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_SEGMENT, "segment", 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 */
315 event = gst_event_new (type);
317 if (!gst_structure_set_parent_refcount (structure,
318 &event->mini_object.refcount))
321 GST_EVENT_STRUCTURE (event) = structure;
328 gst_event_unref (event);
329 g_warning ("structure is already owned by another object");
334 static inline GstStructure *
335 add_structure (GstEvent * event, GQuark name)
337 GstStructure *structure;
339 structure = gst_structure_id_empty_new (name);
340 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
341 /* FIXME, concurrent access can make us leak this */
342 GST_EVENT_STRUCTURE (event) = structure;
347 static GstStructure *
348 update_structure (GstEvent * event)
350 GstStructure *structure;
352 structure = GST_EVENT_STRUCTURE (event);
353 switch (GST_EVENT_TYPE (event)) {
356 if (structure == NULL)
357 structure = add_structure (event, GST_QUARK (EVENT_QOS));
359 gst_structure_id_set (structure,
360 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, GST_EVENT_IMPL (event, qos,
361 type), GST_QUARK (PROPORTION), G_TYPE_DOUBLE,
362 GST_EVENT_IMPL (event, qos, proportion), GST_QUARK (DIFF),
363 G_TYPE_INT64, GST_EVENT_IMPL (event, qos, diff),
364 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, GST_EVENT_IMPL (event, qos,
375 * gst_event_get_structure:
376 * @event: The #GstEvent.
378 * Access the structure of the event.
380 * Returns: The structure of the event. The structure is still
381 * owned by the event, which means that you should not free it and
382 * that the pointer becomes invalid when you free the event.
387 gst_event_get_structure (GstEvent * event)
389 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
391 return update_structure (event);
395 * gst_event_writable_structure:
396 * @event: The #GstEvent.
398 * Get a writable version of the structure.
400 * Returns: The structure of the event. The structure is still
401 * owned by the event, which means that you should not free it and
402 * that the pointer becomes invalid when you free the event.
403 * This function checks if @event is writable and will never return NULL.
408 gst_event_writable_structure (GstEvent * event)
410 GstStructure *structure;
412 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
413 g_return_val_if_fail (gst_event_is_writable (event), NULL);
415 structure = update_structure (event);
417 if (structure == NULL)
419 add_structure (event, gst_event_type_to_quark (GST_EVENT_TYPE (event)));
425 * gst_event_has_name:
426 * @event: The #GstEvent.
427 * @name: name to check
429 * Checks if @event has the given @name. This function is usually used to
430 * check the name of a custom event.
432 * Returns: %TRUE if @name matches the name of the event structure.
437 gst_event_has_name (GstEvent * event, const gchar * name)
439 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
441 if (GST_EVENT_STRUCTURE (event) == NULL)
444 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
448 * gst_event_get_seqnum:
449 * @event: A #GstEvent.
451 * Retrieve the sequence number of a event.
453 * Events have ever-incrementing sequence numbers, which may also be set
454 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
455 * indicate that a event corresponds to some other set of events or messages,
456 * for example an EOS event corresponding to a SEEK event. It is considered good
457 * practice to make this correspondence when possible, though it is not
460 * Note that events and messages share the same sequence number incrementor;
461 * two events or messages will never not have the same sequence number unless
462 * that correspondence was made explicitly.
464 * Returns: The event's sequence number.
471 gst_event_get_seqnum (GstEvent * event)
473 g_return_val_if_fail (GST_IS_EVENT (event), -1);
475 return GST_EVENT_SEQNUM (event);
479 * gst_event_set_seqnum:
480 * @event: A #GstEvent.
481 * @seqnum: A sequence number.
483 * Set the sequence number of a event.
485 * This function might be called by the creator of a event to indicate that the
486 * event relates to other events or messages. See gst_event_get_seqnum() for
494 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
496 g_return_if_fail (GST_IS_EVENT (event));
498 GST_EVENT_SEQNUM (event) = seqnum;
501 /* FIXME 0.11: It would be nice to have flush events
502 * that don't reset the running time in the sinks
506 * gst_event_new_flush_start:
508 * Allocate a new flush start event. The flush start event can be sent
509 * upstream and downstream and travels out-of-bounds with the dataflow.
511 * It marks pads as being flushing and will make them return
512 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
513 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
514 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
515 * on a flushing pad will return %FALSE immediately.
517 * Elements should unlock any blocking functions and exit their streaming
518 * functions as fast as possible when this event is received.
520 * This event is typically generated after a seek to flush out all queued data
521 * in the pipeline so that the new media is played as soon as possible.
523 * Returns: (transfer full): a new flush start event.
526 gst_event_new_flush_start (void)
528 return gst_event_new (GST_EVENT_FLUSH_START);
532 * gst_event_new_flush_stop:
534 * Allocate a new flush stop event. The flush stop event can be sent
535 * upstream and downstream and travels serialized with the dataflow.
536 * It is typically sent after sending a FLUSH_START event to make the
537 * pads accept data again.
539 * Elements can process this event synchronized with the dataflow since
540 * the preceeding FLUSH_START event stopped the dataflow.
542 * This event is typically generated to complete a seek and to resume
545 * Returns: (transfer full): a new flush stop event.
548 gst_event_new_flush_stop (void)
550 return gst_event_new (GST_EVENT_FLUSH_STOP);
556 * Create a new EOS event. The eos event can only travel downstream
557 * synchronized with the buffer flow. Elements that receive the EOS
558 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
559 * when data after the EOS event arrives.
561 * The EOS event will travel down to the sink elements in the pipeline
562 * which will then post the #GST_MESSAGE_EOS on the bus after they have
563 * finished playing any buffered data.
565 * When all sinks have posted an EOS message, an EOS message is
566 * forwarded to the application.
568 * The EOS event itself will not cause any state transitions of the pipeline.
570 * Returns: (transfer full): the new EOS event.
573 gst_event_new_eos (void)
575 return gst_event_new (GST_EVENT_EOS);
579 * gst_event_new_caps:
582 * Create a new CAPS event for @caps. The caps event can only travel downstream
583 * synchronized with the buffer flow and contains the format of the buffers
584 * that will follow after the event.
586 * Returns: (transfer full): the new CAPS event.
589 gst_event_new_caps (GstCaps * caps)
593 g_return_val_if_fail (caps != NULL, NULL);
594 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
596 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
598 event = gst_event_new_custom (GST_EVENT_CAPS,
599 gst_structure_id_new (GST_QUARK (EVENT_CAPS),
600 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
606 * gst_event_parse_caps:
607 * @event: The event to parse
608 * @caps: (out): A pointer to the caps
610 * Get the caps from @event. The caps remains valid as long as @event remains
614 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
616 GstStructure *structure;
618 g_return_if_fail (GST_IS_EVENT (event));
619 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
621 structure = GST_EVENT_STRUCTURE (event);
624 g_value_get_boxed (gst_structure_id_get_value (structure,
629 * gst_event_new_segment:
630 * @segment: a #GstSegment
632 * Create a new SEGMENT event for @segment. The segment event can only travel
633 * downstream synchronized with the buffer flow and contains timing information
634 * and playback properties for the buffers that will follow.
636 * The newsegment event marks the range of buffers to be processed. All
637 * data not within the segment range is not to be processed. This can be
638 * used intelligently by plugins to apply more efficient methods of skipping
639 * unneeded data. The valid range is expressed with the @start and @stop
642 * The time value of the segment is used in conjunction with the start
643 * value to convert the buffer timestamps into the stream time. This is
644 * usually done in sinks to report the current stream_time.
645 * @time represents the stream_time of a buffer carrying a timestamp of
646 * @start. @time cannot be -1.
648 * @start cannot be -1, @stop can be -1. If there
649 * is a valid @stop given, it must be greater or equal the @start, including
650 * when the indicated playback @rate is < 0.
652 * The @applied_rate value provides information about any rate adjustment that
653 * has already been made to the timestamps and content on the buffers of the
654 * stream. (@rate * @applied_rate) should always equal the rate that has been
655 * requested for playback. For example, if an element has an input segment
656 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
657 * incoming timestamps and buffer content by half and output a newsegment event
658 * with @rate of 1.0 and @applied_rate of 2.0
660 * After a newsegment event, the buffer stream time is calculated with:
662 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
664 * Returns: (transfer full): the new SEGMENT event.
667 gst_event_new_segment (GstSegment * segment)
671 g_return_val_if_fail (segment != NULL, NULL);
673 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_PTR_FORMAT,
676 event = gst_event_new_custom (GST_EVENT_SEGMENT,
677 gst_structure_id_new (GST_QUARK (EVENT_SEGMENT),
678 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
684 * gst_event_get_segment:
687 * Get the segment from @event. The segment remains valid as long as @event remains
690 * Returns: the #GstSegment. The segment stays valid for as long as @event is
694 gst_event_get_segment (GstEvent * event)
696 GstStructure *structure;
699 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
700 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT, NULL);
702 structure = GST_EVENT_STRUCTURE (event);
703 segment = g_value_get_boxed (gst_structure_id_get_value (structure,
704 GST_QUARK (SEGMENT)));
710 * gst_event_parse_segment:
711 * @event: The event to parse
712 * @segment: a #GstSegment
714 * Copy the segment values from @event into @segment.
717 gst_event_parse_segment (GstEvent * event, GstSegment * segment)
719 const GstSegment *src;
721 g_return_if_fail (segment != NULL);
723 src = gst_event_get_segment (event);
724 g_return_if_fail (src != NULL);
726 gst_segment_copy_into (src, segment);
731 * @taglist: (transfer full): metadata list. The event will take ownership
734 * Generates a metadata tag event from the given @taglist.
736 * Returns: (transfer full): a new #GstEvent
739 gst_event_new_tag (GstTagList * taglist)
741 g_return_val_if_fail (taglist != NULL, NULL);
743 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
747 * gst_event_parse_tag:
748 * @event: a tag event
749 * @taglist: (out) (transfer none): pointer to metadata list
751 * Parses a tag @event and stores the results in the given @taglist location.
752 * No reference to the taglist will be returned, it remains valid only until
753 * the @event is freed. Don't modify or free the taglist, make a copy if you
754 * want to modify it or store it for later use.
757 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
759 g_return_if_fail (GST_IS_EVENT (event));
760 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
763 *taglist = (GstTagList *) GST_EVENT_STRUCTURE (event);
766 /* buffersize event */
768 * gst_event_new_buffer_size:
769 * @format: buffer format
770 * @minsize: minimum buffer size
771 * @maxsize: maximum buffer size
772 * @async: thread behavior
774 * Create a new buffersize event. The event is sent downstream and notifies
775 * elements that they should provide a buffer of the specified dimensions.
777 * When the @async flag is set, a thread boundary is prefered.
779 * Returns: (transfer full): a new #GstEvent
782 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
783 gint64 maxsize, gboolean async)
786 GstStructure *structure;
788 GST_CAT_INFO (GST_CAT_EVENT,
789 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
790 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
791 minsize, maxsize, async);
793 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
794 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
795 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
796 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
797 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
798 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
804 * gst_event_parse_buffer_size:
805 * @event: The event to query
806 * @format: (out): A pointer to store the format in
807 * @minsize: (out): A pointer to store the minsize in
808 * @maxsize: (out): A pointer to store the maxsize in
809 * @async: (out): A pointer to store the async-flag in
811 * Get the format, minsize, maxsize and async-flag in the buffersize event.
814 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
815 gint64 * minsize, gint64 * maxsize, gboolean * async)
817 const GstStructure *structure;
819 g_return_if_fail (GST_IS_EVENT (event));
820 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
822 structure = GST_EVENT_STRUCTURE (event);
825 g_value_get_enum (gst_structure_id_get_value (structure,
826 GST_QUARK (FORMAT)));
829 g_value_get_int64 (gst_structure_id_get_value (structure,
830 GST_QUARK (MINSIZE)));
833 g_value_get_int64 (gst_structure_id_get_value (structure,
834 GST_QUARK (MAXSIZE)));
837 g_value_get_boolean (gst_structure_id_get_value (structure,
843 * @type: the QoS type
844 * @proportion: the proportion of the qos message
845 * @diff: The time difference of the last Clock sync
846 * @timestamp: The timestamp of the buffer
848 * Allocate a new qos event with the given values.
849 * The QOS event is generated in an element that wants an upstream
850 * element to either reduce or increase its rate because of
851 * high/low CPU load or other resource usage such as network performance or
852 * throttling. Typically sinks generate these events for each buffer
855 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
856 * used when a buffer arrived in time or when the sink cannot keep up with
857 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
858 * receiving buffers fast enough and thus has to drop late buffers.
859 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
860 * by the application, for example to reduce power consumption.
862 * @proportion indicates the real-time performance of the streaming in the
863 * element that generated the QoS event (usually the sink). The value is
864 * generally computed based on more long term statistics about the streams
865 * timestamps compared to the clock.
866 * A value < 1.0 indicates that the upstream element is producing data faster
867 * than real-time. A value > 1.0 indicates that the upstream element is not
868 * producing data fast enough. 1.0 is the ideal @proportion value. The
869 * proportion value can safely be used to lower or increase the quality of
872 * @diff is the difference against the clock in running time of the last
873 * buffer that caused the element to generate the QOS event. A negative value
874 * means that the buffer with @timestamp arrived in time. A positive value
875 * indicates how late the buffer with @timestamp was. When throttling is
876 * enabled, @diff will be set to the requested throttling interval.
878 * @timestamp is the timestamp of the last buffer that cause the element
879 * to generate the QOS event. It is expressed in running time and thus an ever
882 * The upstream element can use the @diff and @timestamp values to decide
883 * whether to process more buffers. For possitive @diff, all buffers with
884 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
885 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
886 * result smaller than 0 is not allowed.
888 * The application can use general event probes to intercept the QoS
889 * event and implement custom application specific QoS handling.
891 * Returns: (transfer full): a new QOS event.
894 gst_event_new_qos (GstQOSType type, gdouble proportion,
895 GstClockTimeDiff diff, GstClockTime timestamp)
899 /* diff must be positive or timestamp + diff must be positive */
900 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
902 GST_CAT_INFO (GST_CAT_EVENT,
903 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
904 ", timestamp %" GST_TIME_FORMAT, type, proportion,
905 diff, GST_TIME_ARGS (timestamp));
907 event = gst_event_new (GST_EVENT_QOS);
909 GST_EVENT_IMPL (event, qos, type) = type;
910 GST_EVENT_IMPL (event, qos, proportion) = proportion;
911 GST_EVENT_IMPL (event, qos, diff) = diff;
912 GST_EVENT_IMPL (event, qos, timestamp) = timestamp;
918 * gst_event_parse_qos:
919 * @event: The event to query
920 * @type: (out): A pointer to store the QoS type in
921 * @proportion: (out): A pointer to store the proportion in
922 * @diff: (out): A pointer to store the diff in
923 * @timestamp: (out): A pointer to store the timestamp in
925 * Get the type, proportion, diff and timestamp in the qos event. See
926 * gst_event_new_qos() for more information about the different QoS values.
929 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
930 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
932 g_return_if_fail (GST_IS_EVENT (event));
933 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
936 *type = GST_EVENT_IMPL (event, qos, type);
938 *proportion = GST_EVENT_IMPL (event, qos, proportion);
940 *diff = GST_EVENT_IMPL (event, qos, diff);
942 *timestamp = GST_EVENT_IMPL (event, qos, timestamp);
946 * gst_event_new_seek:
947 * @rate: The new playback rate
948 * @format: The format of the seek values
949 * @flags: The optional seek flags
950 * @start_type: The type and flags for the new start position
951 * @start: The value of the new start position
952 * @stop_type: The type and flags for the new stop position
953 * @stop: The value of the new stop position
955 * Allocate a new seek event with the given parameters.
957 * The seek event configures playback of the pipeline between @start to @stop
958 * at the speed given in @rate, also called a playback segment.
959 * The @start and @stop values are expressed in @format.
961 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
962 * Negatives values means backwards playback. A value of 0.0 for the
963 * rate is not allowed and should be accomplished instead by PAUSING the
966 * A pipeline has a default playback segment configured with a start
967 * position of 0, a stop position of -1 and a rate of 1.0. The currently
968 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
970 * @start_type and @stop_type specify how to adjust the currently configured
971 * start and stop fields in playback segment. Adjustments can be made relative
972 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
973 * means that the position should not be updated.
975 * When the rate is positive and @start has been updated, playback will start
976 * from the newly configured start position.
978 * For negative rates, playback will start from the newly configured stop
979 * position (if any). If the stop position if updated, it must be different from
980 * -1 for negative rates.
982 * It is not possible to seek relative to the current playback position, to do
983 * this, PAUSE the pipeline, query the current playback position with
984 * #GST_QUERY_POSITION and update the playback segment current position with a
985 * #GST_SEEK_TYPE_SET to the desired position.
987 * Returns: (transfer full): a new seek event.
990 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
991 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
994 GstStructure *structure;
996 g_return_val_if_fail (rate != 0.0, NULL);
998 if (format == GST_FORMAT_TIME) {
999 GST_CAT_INFO (GST_CAT_EVENT,
1000 "creating seek rate %lf, format TIME, flags %d, "
1001 "start_type %d, start %" GST_TIME_FORMAT ", "
1002 "stop_type %d, stop %" GST_TIME_FORMAT,
1003 rate, flags, start_type, GST_TIME_ARGS (start),
1004 stop_type, GST_TIME_ARGS (stop));
1006 GST_CAT_INFO (GST_CAT_EVENT,
1007 "creating seek rate %lf, format %s, flags %d, "
1008 "start_type %d, start %" G_GINT64_FORMAT ", "
1009 "stop_type %d, stop %" G_GINT64_FORMAT,
1010 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1014 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1015 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1016 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1017 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1018 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1019 GST_QUARK (CUR), G_TYPE_INT64, start,
1020 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1021 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1022 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1028 * gst_event_parse_seek:
1029 * @event: a seek event
1030 * @rate: (out): result location for the rate
1031 * @format: (out): result location for the stream format
1032 * @flags: (out): result location for the #GstSeekFlags
1033 * @start_type: (out): result location for the #GstSeekType of the start position
1034 * @start: (out): result location for the start postion expressed in @format
1035 * @stop_type: (out): result location for the #GstSeekType of the stop position
1036 * @stop: (out): result location for the stop postion expressed in @format
1038 * Parses a seek @event and stores the results in the given result locations.
1041 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1042 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1043 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1045 const GstStructure *structure;
1047 g_return_if_fail (GST_IS_EVENT (event));
1048 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1050 structure = GST_EVENT_STRUCTURE (event);
1053 g_value_get_double (gst_structure_id_get_value (structure,
1057 g_value_get_enum (gst_structure_id_get_value (structure,
1058 GST_QUARK (FORMAT)));
1061 g_value_get_flags (gst_structure_id_get_value (structure,
1062 GST_QUARK (FLAGS)));
1065 g_value_get_enum (gst_structure_id_get_value (structure,
1066 GST_QUARK (CUR_TYPE)));
1069 g_value_get_int64 (gst_structure_id_get_value (structure,
1073 g_value_get_enum (gst_structure_id_get_value (structure,
1074 GST_QUARK (STOP_TYPE)));
1077 g_value_get_int64 (gst_structure_id_get_value (structure,
1082 * gst_event_new_navigation:
1083 * @structure: (transfer full): description of the event. The event will take
1084 * ownership of the structure.
1086 * Create a new navigation event from the given description.
1088 * Returns: (transfer full): a new #GstEvent
1091 gst_event_new_navigation (GstStructure * structure)
1093 g_return_val_if_fail (structure != NULL, NULL);
1095 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1099 * gst_event_new_latency:
1100 * @latency: the new latency value
1102 * Create a new latency event. The event is sent upstream from the sinks and
1103 * notifies elements that they should add an additional @latency to the
1104 * running time before synchronising against the clock.
1106 * The latency is mostly used in live sinks and is always expressed in
1109 * Returns: (transfer full): a new #GstEvent
1114 gst_event_new_latency (GstClockTime latency)
1117 GstStructure *structure;
1119 GST_CAT_INFO (GST_CAT_EVENT,
1120 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1122 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1123 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1124 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1130 * gst_event_parse_latency:
1131 * @event: The event to query
1132 * @latency: (out): A pointer to store the latency in.
1134 * Get the latency in the latency event.
1139 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1141 g_return_if_fail (GST_IS_EVENT (event));
1142 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1146 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1147 (event), GST_QUARK (LATENCY)));
1151 * gst_event_new_step:
1152 * @format: the format of @amount
1153 * @amount: the amount of data to step
1154 * @rate: the step rate
1155 * @flush: flushing steps
1156 * @intermediate: intermediate steps
1158 * Create a new step event. The purpose of the step event is to instruct a sink
1159 * to skip @amount (expressed in @format) of media. It can be used to implement
1160 * stepping through the video frame by frame or for doing fast trick modes.
1162 * A rate of <= 0.0 is not allowed, pause the pipeline or reverse the playback
1163 * direction of the pipeline to get the same effect.
1165 * The @flush flag will clear any pending data in the pipeline before starting
1166 * the step operation.
1168 * The @intermediate flag instructs the pipeline that this step operation is
1169 * part of a larger step operation.
1171 * Returns: (transfer full): a new #GstEvent
1176 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1177 gboolean flush, gboolean intermediate)
1180 GstStructure *structure;
1182 g_return_val_if_fail (rate > 0.0, NULL);
1184 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1186 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1187 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1188 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1189 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1190 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1191 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1192 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1198 * gst_event_parse_step:
1199 * @event: The event to query
1200 * @format: (out) (allow-none): a pointer to store the format in
1201 * @amount: (out) (allow-none): a pointer to store the amount in
1202 * @rate: (out) (allow-none): a pointer to store the rate in
1203 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1204 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1207 * Parse the step event.
1212 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1213 gdouble * rate, gboolean * flush, gboolean * intermediate)
1215 const GstStructure *structure;
1217 g_return_if_fail (GST_IS_EVENT (event));
1218 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1220 structure = GST_EVENT_STRUCTURE (event);
1222 *format = g_value_get_enum (gst_structure_id_get_value (structure,
1223 GST_QUARK (FORMAT)));
1225 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1226 GST_QUARK (AMOUNT)));
1228 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1231 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1232 GST_QUARK (FLUSH)));
1234 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1235 GST_QUARK (INTERMEDIATE)));
1239 * gst_event_new_reconfigure:
1241 * Create a new reconfigure event. The purpose of the reconfingure event is
1242 * to travel upstream and make elements renegotiate their caps or reconfigure
1243 * their buffer pools. This is useful when changing properties on elements
1244 * or changing the topology of the pipeline.
1246 * Returns: (transfer full): a new #GstEvent
1251 gst_event_new_reconfigure (void)
1255 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1257 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1263 * gst_event_new_sink_message:
1264 * @msg: (transfer none): the #GstMessage to be posted
1266 * Create a new sink-message event. The purpose of the sink-message event is
1267 * to instruct a sink to post the message contained in the event synchronized
1270 * Returns: (transfer full): a new #GstEvent
1274 /* FIXME 0.11: take ownership of msg for consistency? */
1276 gst_event_new_sink_message (GstMessage * msg)
1279 GstStructure *structure;
1281 g_return_val_if_fail (msg != NULL, NULL);
1283 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1285 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1286 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1287 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1293 * gst_event_parse_sink_message:
1294 * @event: The event to query
1295 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1297 * Parse the sink-message event. Unref @msg after usage.
1302 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1304 const GstStructure *structure;
1306 g_return_if_fail (GST_IS_EVENT (event));
1307 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1309 structure = GST_EVENT_STRUCTURE (event);
1312 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1313 (structure, GST_QUARK (MESSAGE))));