2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wim.taymans@chello.be>
4 * 2005 Wim Taymans <wim@fluendo.com>
6 * gstevent.c: GstEvent subsystem
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
26 * @short_description: Structure describing events that are passed up and down
28 * @see_also: #GstPad, #GstElement
30 * The event class provides factory methods to construct events for sending
31 * and functions to query (parse) received events.
33 * Events are usually created with gst_event_new_*() which takes event-type
34 * specific parameters as arguments.
35 * To send an event application will usually use gst_element_send_event() and
36 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 * The event should be unreffed with gst_event_unref() if it has not been sent.
39 * Events that have been received can be parsed with their respective
40 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
42 * Events are passed between elements in parallel to the data stream. Some events
43 * are serialized with buffers, others are not. Some events only travel downstream,
44 * others only upstream. Some events can travel both upstream and downstream.
46 * The events are used to signal special conditions in the datastream such as
47 * EOS (end of stream) or the start of a new stream-segment.
48 * Events are also used to flush the pipeline of any pending data.
50 * Most of the event API is used inside plugins. Applications usually only
51 * construct and use seek events.
52 * To do that gst_event_new_seek() is used to create a seek event. It takes
53 * the needed parameters to specify seeking time and mode.
55 * <title>performing a seek on a pipeline</title>
60 * // construct a seek event to play the media from second 2 to 5, flush
61 * // the pipeline to decrease latency.
62 * event = gst_event_new_seek (1.0,
64 * GST_SEEK_FLAG_FLUSH,
65 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
66 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
68 * result = gst_element_send_event (pipeline, event);
70 * g_warning ("seek failed");
75 * Last reviewed on 2006-09-6 (0.10.10)
79 #include "gst_private.h"
80 #include <string.h> /* memcpy */
84 #include "gstenumtypes.h"
88 #define GST_EVENT_SEQNUM(e) ((GstEvent*)e)->abidata.seqnum
90 static void gst_event_finalize (GstEvent * event);
91 static GstEvent *_gst_event_copy (GstEvent * event);
93 static GstMiniObjectClass *parent_class = NULL;
96 _gst_event_initialize (void)
98 g_type_class_ref (gst_event_get_type ());
99 g_type_class_ref (gst_seek_flags_get_type ());
100 g_type_class_ref (gst_seek_type_get_type ());
110 static GstEventQuarks event_quarks[] = {
111 {GST_EVENT_UNKNOWN, "unknown", 0},
112 {GST_EVENT_FLUSH_START, "flush-start", 0},
113 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
114 {GST_EVENT_EOS, "eos", 0},
115 {GST_EVENT_NEWSEGMENT, "newsegment", 0},
116 {GST_EVENT_TAG, "tag", 0},
117 {GST_EVENT_TOC, "toc", 0},
118 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
119 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
120 {GST_EVENT_QOS, "qos", 0},
121 {GST_EVENT_SEEK, "seek", 0},
122 {GST_EVENT_NAVIGATION, "navigation", 0},
123 {GST_EVENT_LATENCY, "latency", 0},
124 {GST_EVENT_STEP, "step", 0},
125 {GST_EVENT_TOC_SELECT, "toc-select", 0},
126 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
127 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
128 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
129 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
130 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
136 * gst_event_type_get_name:
137 * @type: the event type
139 * Get a printable name for the given event type. Do not modify or free.
141 * Returns: a reference to the static name of the event.
144 gst_event_type_get_name (GstEventType type)
148 for (i = 0; event_quarks[i].name; i++) {
149 if (type == event_quarks[i].type)
150 return event_quarks[i].name;
156 * gst_event_type_to_quark:
157 * @type: the event type
159 * Get the unique quark for the given event type.
161 * Returns: the quark associated with the event type
164 gst_event_type_to_quark (GstEventType type)
168 for (i = 0; event_quarks[i].name; i++) {
169 if (type == event_quarks[i].type)
170 return event_quarks[i].quark;
176 * gst_event_type_get_flags:
177 * @type: a #GstEventType
179 * Gets the #GstEventTypeFlags associated with @type.
181 * Returns: a #GstEventTypeFlags.
184 gst_event_type_get_flags (GstEventType type)
186 GstEventTypeFlags ret;
188 ret = type & ((1 << GST_EVENT_TYPE_SHIFT) - 1);
197 for (i = 0; event_quarks[i].name; i++) { \
198 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name); \
202 G_DEFINE_TYPE_WITH_CODE (GstEvent, gst_event, GST_TYPE_MINI_OBJECT, _do_init);
205 gst_event_class_init (GstEventClass * klass)
207 parent_class = g_type_class_peek_parent (klass);
209 klass->mini_object_class.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
210 klass->mini_object_class.finalize =
211 (GstMiniObjectFinalizeFunction) gst_event_finalize;
215 gst_event_init (GstEvent * event)
217 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
221 gst_event_finalize (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 if (GST_EVENT_SRC (event)) {
230 gst_object_unref (GST_EVENT_SRC (event));
231 GST_EVENT_SRC (event) = NULL;
233 if (event->structure) {
234 gst_structure_set_parent_refcount (event->structure, NULL);
235 gst_structure_free (event->structure);
238 /* GST_MINI_OBJECT_CLASS (parent_class)->finalize (GST_MINI_OBJECT (event)); */
242 _gst_event_copy (GstEvent * event)
246 copy = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
248 GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
249 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
250 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
252 if (GST_EVENT_SRC (event)) {
253 GST_EVENT_SRC (copy) = gst_object_ref (GST_EVENT_SRC (event));
255 if (event->structure) {
256 copy->structure = gst_structure_copy (event->structure);
257 gst_structure_set_parent_refcount (copy->structure,
258 ©->mini_object.refcount);
264 gst_event_new (GstEventType type)
268 event = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
270 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
271 gst_event_type_get_name (type), type);
275 event->structure = NULL;
276 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
282 * gst_event_new_custom:
283 * @type: The type of the new event
284 * @structure: (transfer full): the structure for the event. The event will
285 * take ownership of the structure.
287 * Create a new custom-typed event. This can be used for anything not
288 * handled by other event-specific functions to pass an event to another
291 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
292 * assigning a free number and filling in the correct direction and
293 * serialization flags.
295 * New custom events can also be created by subclassing the event type if
298 * Returns: (transfer full): the new custom event.
301 gst_event_new_custom (GstEventType type, GstStructure * structure)
305 /* structure must not have a parent */
307 g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
309 event = gst_event_new (type);
311 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
312 event->structure = structure;
318 * gst_event_get_structure:
319 * @event: The #GstEvent.
321 * Access the structure of the event.
323 * Returns: The structure of the event. The structure is still
324 * owned by the event, which means that you should not free it and
325 * that the pointer becomes invalid when you free the event.
330 gst_event_get_structure (GstEvent * event)
332 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
334 return event->structure;
338 * gst_event_has_name:
339 * @event: The #GstEvent.
340 * @name: name to check
342 * Checks if @event has the given @name. This function is usually used to
343 * check the name of a custom event.
345 * Returns: %TRUE if @name matches the name of the event structure.
350 gst_event_has_name (GstEvent * event, const gchar * name)
352 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
354 if (event->structure == NULL)
357 return gst_structure_has_name (event->structure, name);
361 * gst_event_get_seqnum:
362 * @event: A #GstEvent.
364 * Retrieve the sequence number of a event.
366 * Events have ever-incrementing sequence numbers, which may also be set
367 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
368 * indicate that a event corresponds to some other set of events or messages,
369 * for example an EOS event corresponding to a SEEK event. It is considered good
370 * practice to make this correspondence when possible, though it is not
373 * Note that events and messages share the same sequence number incrementor;
374 * two events or messages will never have the same sequence number unless
375 * that correspondence was made explicitly.
377 * Returns: The event's sequence number.
384 gst_event_get_seqnum (GstEvent * event)
386 g_return_val_if_fail (GST_IS_EVENT (event), -1);
388 return GST_EVENT_SEQNUM (event);
392 * gst_event_set_seqnum:
393 * @event: A #GstEvent.
394 * @seqnum: A sequence number.
396 * Set the sequence number of a event.
398 * This function might be called by the creator of a event to indicate that the
399 * event relates to other events or messages. See gst_event_get_seqnum() for
407 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
409 g_return_if_fail (GST_IS_EVENT (event));
411 GST_EVENT_SEQNUM (event) = seqnum;
414 /* FIXME 0.11: It would be nice to have flush events
415 * that don't reset the running time in the sinks
419 * gst_event_new_flush_start:
421 * Allocate a new flush start event. The flush start event can be sent
422 * upstream and downstream and travels out-of-bounds with the dataflow.
424 * It marks pads as being flushing and will make them return
425 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
426 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
427 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
428 * on a flushing pad will return %FALSE immediately.
430 * Elements should unlock any blocking functions and exit their streaming
431 * functions as fast as possible when this event is received.
433 * This event is typically generated after a seek to flush out all queued data
434 * in the pipeline so that the new media is played as soon as possible.
436 * Returns: (transfer full): a new flush start event.
439 gst_event_new_flush_start (void)
441 return gst_event_new (GST_EVENT_FLUSH_START);
445 * gst_event_new_flush_stop:
447 * Allocate a new flush stop event. The flush stop event can be sent
448 * upstream and downstream and travels serialized with the dataflow.
449 * It is typically sent after sending a FLUSH_START event to make the
450 * pads accept data again.
452 * Elements can process this event synchronized with the dataflow since
453 * the preceeding FLUSH_START event stopped the dataflow.
455 * This event is typically generated to complete a seek and to resume
458 * Returns: (transfer full): a new flush stop event.
461 gst_event_new_flush_stop (void)
463 return gst_event_new (GST_EVENT_FLUSH_STOP);
469 * Create a new EOS event. The eos event can only travel downstream
470 * synchronized with the buffer flow. Elements that receive the EOS
471 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
472 * when data after the EOS event arrives.
474 * The EOS event will travel down to the sink elements in the pipeline
475 * which will then post the #GST_MESSAGE_EOS on the bus after they have
476 * finished playing any buffered data.
478 * When all sinks have posted an EOS message, an EOS message is
479 * forwarded to the application.
481 * The EOS event itself will not cause any state transitions of the pipeline.
483 * Returns: (transfer full): the new EOS event.
486 gst_event_new_eos (void)
488 return gst_event_new (GST_EVENT_EOS);
492 * gst_event_new_new_segment:
493 * @update: is this segment an update to a previous one
494 * @rate: a new rate for playback
495 * @format: The format of the segment values
496 * @start: the start value of the segment
497 * @stop: the stop value of the segment
498 * @position: stream position
500 * Allocate a new newsegment event with the given format/values tripplets
502 * This method calls gst_event_new_new_segment_full() passing a default
503 * value of 1.0 for applied_rate
505 * Returns: (transfer full): a new newsegment event.
508 gst_event_new_new_segment (gboolean update, gdouble rate, GstFormat format,
509 gint64 start, gint64 stop, gint64 position)
511 return gst_event_new_new_segment_full (update, rate, 1.0, format, start,
516 * gst_event_parse_new_segment:
517 * @event: The event to query
518 * @update: (out): A pointer to the update flag of the segment
519 * @rate: (out): A pointer to the rate of the segment
520 * @format: (out): A pointer to the format of the newsegment values
521 * @start: (out): A pointer to store the start value in
522 * @stop: (out): A pointer to store the stop value in
523 * @position: (out): A pointer to store the stream time in
525 * Get the update flag, rate, format, start, stop and position in the
526 * newsegment event. In general, gst_event_parse_new_segment_full() should
527 * be used instead of this, to also retrieve the applied_rate value of the
528 * segment. See gst_event_new_new_segment_full() for a full description
529 * of the newsegment event.
532 gst_event_parse_new_segment (GstEvent * event, gboolean * update,
533 gdouble * rate, GstFormat * format, gint64 * start,
534 gint64 * stop, gint64 * position)
536 gst_event_parse_new_segment_full (event, update, rate, NULL, format, start,
541 * gst_event_new_new_segment_full:
542 * @update: Whether this segment is an update to a previous one
543 * @rate: A new rate for playback
544 * @applied_rate: The rate factor which has already been applied
545 * @format: The format of the segment values
546 * @start: The start value of the segment
547 * @stop: The stop value of the segment
548 * @position: stream position
550 * Allocate a new newsegment event with the given format/values triplets.
552 * The newsegment event marks the range of buffers to be processed. All
553 * data not within the segment range is not to be processed. This can be
554 * used intelligently by plugins to apply more efficient methods of skipping
555 * unneeded data. The valid range is expressed with the @start and @stop
558 * The position value of the segment is used in conjunction with the start
559 * value to convert the buffer timestamps into the stream time. This is
560 * usually done in sinks to report the current stream_time.
561 * @position represents the stream_time of a buffer carrying a timestamp of
562 * @start. @position cannot be -1.
564 * @start cannot be -1, @stop can be -1. If there
565 * is a valid @stop given, it must be greater or equal the @start, including
566 * when the indicated playback @rate is < 0.
568 * The @applied_rate value provides information about any rate adjustment that
569 * has already been made to the timestamps and content on the buffers of the
570 * stream. (@rate * @applied_rate) should always equal the rate that has been
571 * requested for playback. For example, if an element has an input segment
572 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
573 * incoming timestamps and buffer content by half and output a newsegment event
574 * with @rate of 1.0 and @applied_rate of 2.0
576 * After a newsegment event, the buffer stream time is calculated with:
578 * position + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
580 * Returns: (transfer full): a new newsegment event.
585 gst_event_new_new_segment_full (gboolean update, gdouble rate,
586 gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
590 GstStructure *structure;
592 g_return_val_if_fail (rate != 0.0, NULL);
593 g_return_val_if_fail (applied_rate != 0.0, NULL);
594 g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, NULL);
596 if (format == GST_FORMAT_TIME) {
597 GST_CAT_INFO (GST_CAT_EVENT,
598 "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
599 "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
600 ", position %" GST_TIME_FORMAT,
601 update, rate, GST_TIME_ARGS (start),
602 GST_TIME_ARGS (stop), GST_TIME_ARGS (position));
604 GST_CAT_INFO (GST_CAT_EVENT,
605 "creating newsegment update %d, rate %lf, format %s, "
606 "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", position %"
607 G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
611 g_return_val_if_fail (position != -1, NULL);
612 g_return_val_if_fail (start != -1, NULL);
614 g_return_val_if_fail (start <= stop, NULL);
616 structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
617 GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
618 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
619 GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
620 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
621 GST_QUARK (START), G_TYPE_INT64, start,
622 GST_QUARK (STOP), G_TYPE_INT64, stop,
623 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
624 event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
630 * gst_event_parse_new_segment_full:
631 * @event: The event to query
632 * @update: (out): A pointer to the update flag of the segment
633 * @rate: (out): A pointer to the rate of the segment
634 * @applied_rate: (out): A pointer to the applied_rate of the segment
635 * @format: (out): A pointer to the format of the newsegment values
636 * @start: (out): A pointer to store the start value in
637 * @stop: (out): A pointer to store the stop value in
638 * @position: (out): A pointer to store the stream time in
640 * Get the update, rate, applied_rate, format, start, stop and
641 * position in the newsegment event. See gst_event_new_new_segment_full()
642 * for a full description of the newsegment event.
647 gst_event_parse_new_segment_full (GstEvent * event, gboolean * update,
648 gdouble * rate, gdouble * applied_rate, GstFormat * format,
649 gint64 * start, gint64 * stop, gint64 * position)
651 const GstStructure *structure;
653 g_return_if_fail (GST_IS_EVENT (event));
654 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
656 structure = event->structure;
657 if (G_LIKELY (update))
659 g_value_get_boolean (gst_structure_id_get_value (structure,
660 GST_QUARK (UPDATE)));
663 g_value_get_double (gst_structure_id_get_value (structure,
665 if (G_LIKELY (applied_rate))
667 g_value_get_double (gst_structure_id_get_value (structure,
668 GST_QUARK (APPLIED_RATE)));
669 if (G_LIKELY (format))
670 *format = (GstFormat)
671 g_value_get_enum (gst_structure_id_get_value (structure,
672 GST_QUARK (FORMAT)));
673 if (G_LIKELY (start))
675 g_value_get_int64 (gst_structure_id_get_value (structure,
679 g_value_get_int64 (gst_structure_id_get_value (structure,
681 if (G_LIKELY (position))
683 g_value_get_int64 (gst_structure_id_get_value (structure,
684 GST_QUARK (POSITION)));
689 * @taglist: (transfer full): metadata list. The event will take ownership
692 * Generates a metadata tag event from the given @taglist.
694 * Returns: (transfer full): a new #GstEvent
697 gst_event_new_tag (GstTagList * taglist)
699 g_return_val_if_fail (taglist != NULL, NULL);
701 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
705 * gst_event_parse_tag:
706 * @event: a tag event
707 * @taglist: (out) (transfer none): pointer to metadata list
709 * Parses a tag @event and stores the results in the given @taglist location.
710 * No reference to the taglist will be returned, it remains valid only until
711 * the @event is freed. Don't modify or free the taglist, make a copy if you
712 * want to modify it or store it for later use.
715 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
717 g_return_if_fail (GST_IS_EVENT (event));
718 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
721 *taglist = (GstTagList *) event->structure;
724 /* buffersize event */
726 * gst_event_new_buffer_size:
727 * @format: buffer format
728 * @minsize: minimum buffer size
729 * @maxsize: maximum buffer size
730 * @async: thread behavior
732 * Create a new buffersize event. The event is sent downstream and notifies
733 * elements that they should provide a buffer of the specified dimensions.
735 * When the @async flag is set, a thread boundary is preferred.
737 * Returns: (transfer full): a new #GstEvent
740 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
741 gint64 maxsize, gboolean async)
744 GstStructure *structure;
746 GST_CAT_INFO (GST_CAT_EVENT,
747 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
748 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
749 minsize, maxsize, async);
751 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
752 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
753 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
754 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
755 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
756 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
762 * gst_event_parse_buffer_size:
763 * @event: The event to query
764 * @format: (out): A pointer to store the format in
765 * @minsize: (out): A pointer to store the minsize in
766 * @maxsize: (out): A pointer to store the maxsize in
767 * @async: (out): A pointer to store the async-flag in
769 * Get the format, minsize, maxsize and async-flag in the buffersize event.
772 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
773 gint64 * minsize, gint64 * maxsize, gboolean * async)
775 const GstStructure *structure;
777 g_return_if_fail (GST_IS_EVENT (event));
778 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
780 structure = event->structure;
782 *format = (GstFormat)
783 g_value_get_enum (gst_structure_id_get_value (structure,
784 GST_QUARK (FORMAT)));
787 g_value_get_int64 (gst_structure_id_get_value (structure,
788 GST_QUARK (MINSIZE)));
791 g_value_get_int64 (gst_structure_id_get_value (structure,
792 GST_QUARK (MAXSIZE)));
795 g_value_get_boolean (gst_structure_id_get_value (structure,
801 * @proportion: the proportion of the qos message
802 * @diff: The time difference of the last Clock sync
803 * @timestamp: The timestamp of the buffer
805 * Allocate a new qos event with the given values. This function calls
806 * gst_event_new_qos_full() with the type set to #GST_QOS_TYPE_OVERFLOW
807 * when diff is negative (buffers are in time) and #GST_QOS_TYPE_UNDERFLOW
808 * when @diff is positive (buffers are late).
810 * Returns: (transfer full): a new QOS event.
813 gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
814 GstClockTime timestamp)
819 type = GST_QOS_TYPE_OVERFLOW;
821 type = GST_QOS_TYPE_UNDERFLOW;
823 return gst_event_new_qos_full (type, proportion, diff, timestamp);
827 * gst_event_new_qos_full:
828 * @type: the QoS type
829 * @proportion: the proportion of the qos message
830 * @diff: The time difference of the last Clock sync
831 * @timestamp: The timestamp of the buffer
833 * Allocate a new qos event with the given values.
834 * The QOS event is generated in an element that wants an upstream
835 * element to either reduce or increase its rate because of
836 * high/low CPU load or other resource usage such as network performance or
837 * throttling. Typically sinks generate these events for each buffer
840 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
841 * used when a buffer arrived in time or when the sink cannot keep up with
842 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
843 * receiving buffers fast enough and thus has to drop late buffers.
844 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
845 * by the application, for example to reduce power consumption.
847 * @proportion indicates the real-time performance of the streaming in the
848 * element that generated the QoS event (usually the sink). The value is
849 * generally computed based on more long term statistics about the streams
850 * timestamps compared to the clock.
851 * A value < 1.0 indicates that the upstream element is producing data faster
852 * than real-time. A value > 1.0 indicates that the upstream element is not
853 * producing data fast enough. 1.0 is the ideal @proportion value. The
854 * proportion value can safely be used to lower or increase the quality of
857 * @diff is the difference against the clock in running time of the last
858 * buffer that caused the element to generate the QOS event. A negative value
859 * means that the buffer with @timestamp arrived in time. A positive value
860 * indicates how late the buffer with @timestamp was. When throttling is
861 * enabled, @diff will be set to the requested throttling interval.
863 * @timestamp is the timestamp of the last buffer that cause the element
864 * to generate the QOS event. It is expressed in running time and thus an ever
867 * The upstream element can use the @diff and @timestamp values to decide
868 * whether to process more buffers. For possitive @diff, all buffers with
869 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
870 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
871 * result smaller than 0 is not allowed.
873 * The application can use general event probes to intercept the QoS
874 * event and implement custom application specific QoS handling.
876 * Returns: (transfer full): a new QOS event.
881 gst_event_new_qos_full (GstQOSType type, gdouble proportion,
882 GstClockTimeDiff diff, GstClockTime timestamp)
885 GstStructure *structure;
887 /* diff must be positive or timestamp + diff must be positive */
888 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
890 GST_CAT_INFO (GST_CAT_EVENT,
891 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
892 ", timestamp %" GST_TIME_FORMAT, type, proportion,
893 diff, GST_TIME_ARGS (timestamp));
895 structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
896 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
897 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
898 GST_QUARK (DIFF), G_TYPE_INT64, diff,
899 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
900 event = gst_event_new_custom (GST_EVENT_QOS, structure);
906 * gst_event_parse_qos:
907 * @event: The event to query
908 * @proportion: (out): A pointer to store the proportion in
909 * @diff: (out): A pointer to store the diff in
910 * @timestamp: (out): A pointer to store the timestamp in
912 * Get the proportion, diff and timestamp in the qos event. See
913 * gst_event_new_qos() for more information about the different QoS values.
916 gst_event_parse_qos (GstEvent * event, gdouble * proportion,
917 GstClockTimeDiff * diff, GstClockTime * timestamp)
919 gst_event_parse_qos_full (event, NULL, proportion, diff, timestamp);
923 * gst_event_parse_qos_full:
924 * @event: The event to query
925 * @type: (out): A pointer to store the QoS type in
926 * @proportion: (out): A pointer to store the proportion in
927 * @diff: (out): A pointer to store the diff in
928 * @timestamp: (out): A pointer to store the timestamp in
930 * Get the type, proportion, diff and timestamp in the qos event. See
931 * gst_event_new_qos_full() for more information about the different QoS values.
936 gst_event_parse_qos_full (GstEvent * event, GstQOSType * type,
937 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
939 const GstStructure *structure;
941 g_return_if_fail (GST_IS_EVENT (event));
942 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
944 structure = event->structure;
947 g_value_get_enum (gst_structure_id_get_value (structure,
951 g_value_get_double (gst_structure_id_get_value (structure,
952 GST_QUARK (PROPORTION)));
955 g_value_get_int64 (gst_structure_id_get_value (structure,
959 g_value_get_uint64 (gst_structure_id_get_value (structure,
960 GST_QUARK (TIMESTAMP)));
964 * gst_event_new_seek:
965 * @rate: The new playback rate
966 * @format: The format of the seek values
967 * @flags: The optional seek flags
968 * @start_type: The type and flags for the new start position
969 * @start: The value of the new start position
970 * @stop_type: The type and flags for the new stop position
971 * @stop: The value of the new stop position
973 * Allocate a new seek event with the given parameters.
975 * The seek event configures playback of the pipeline between @start to @stop
976 * at the speed given in @rate, also called a playback segment.
977 * The @start and @stop values are expressed in @format.
979 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
980 * Negatives values means backwards playback. A value of 0.0 for the
981 * rate is not allowed and should be accomplished instead by PAUSING the
984 * A pipeline has a default playback segment configured with a start
985 * position of 0, a stop position of -1 and a rate of 1.0. The currently
986 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
988 * @start_type and @stop_type specify how to adjust the currently configured
989 * start and stop fields in playback segment. Adjustments can be made relative
990 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
991 * means that the position should not be updated.
993 * When the rate is positive and @start has been updated, playback will start
994 * from the newly configured start position.
996 * For negative rates, playback will start from the newly configured stop
997 * position (if any). If the stop position if updated, it must be different from
998 * -1 for negative rates.
1000 * It is not possible to seek relative to the current playback position, to do
1001 * this, PAUSE the pipeline, query the current playback position with
1002 * #GST_QUERY_POSITION and update the playback segment current position with a
1003 * #GST_SEEK_TYPE_SET to the desired position.
1005 * Returns: (transfer full): a new seek event.
1008 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1009 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1012 GstStructure *structure;
1014 g_return_val_if_fail (rate != 0.0, NULL);
1016 if (format == GST_FORMAT_TIME) {
1017 GST_CAT_INFO (GST_CAT_EVENT,
1018 "creating seek rate %lf, format TIME, flags %d, "
1019 "start_type %d, start %" GST_TIME_FORMAT ", "
1020 "stop_type %d, stop %" GST_TIME_FORMAT,
1021 rate, flags, start_type, GST_TIME_ARGS (start),
1022 stop_type, GST_TIME_ARGS (stop));
1024 GST_CAT_INFO (GST_CAT_EVENT,
1025 "creating seek rate %lf, format %s, flags %d, "
1026 "start_type %d, start %" G_GINT64_FORMAT ", "
1027 "stop_type %d, stop %" G_GINT64_FORMAT,
1028 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1032 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1033 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1034 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1035 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1036 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1037 GST_QUARK (CUR), G_TYPE_INT64, start,
1038 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1039 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1040 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1046 * gst_event_parse_seek:
1047 * @event: a seek event
1048 * @rate: (out): result location for the rate
1049 * @format: (out): result location for the stream format
1050 * @flags: (out): result location for the #GstSeekFlags
1051 * @start_type: (out): result location for the #GstSeekType of the start position
1052 * @start: (out): result location for the start postion expressed in @format
1053 * @stop_type: (out): result location for the #GstSeekType of the stop position
1054 * @stop: (out): result location for the stop postion expressed in @format
1056 * Parses a seek @event and stores the results in the given result locations.
1059 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1060 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1061 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1063 const GstStructure *structure;
1065 g_return_if_fail (GST_IS_EVENT (event));
1066 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1068 structure = event->structure;
1071 g_value_get_double (gst_structure_id_get_value (structure,
1074 *format = (GstFormat)
1075 g_value_get_enum (gst_structure_id_get_value (structure,
1076 GST_QUARK (FORMAT)));
1078 *flags = (GstSeekFlags)
1079 g_value_get_flags (gst_structure_id_get_value (structure,
1080 GST_QUARK (FLAGS)));
1082 *start_type = (GstSeekType)
1083 g_value_get_enum (gst_structure_id_get_value (structure,
1084 GST_QUARK (CUR_TYPE)));
1087 g_value_get_int64 (gst_structure_id_get_value (structure,
1090 *stop_type = (GstSeekType)
1091 g_value_get_enum (gst_structure_id_get_value (structure,
1092 GST_QUARK (STOP_TYPE)));
1095 g_value_get_int64 (gst_structure_id_get_value (structure,
1100 * gst_event_new_navigation:
1101 * @structure: (transfer full): description of the event. The event will take
1102 * ownership of the structure.
1104 * Create a new navigation event from the given description.
1106 * Returns: (transfer full): a new #GstEvent
1109 gst_event_new_navigation (GstStructure * structure)
1111 g_return_val_if_fail (structure != NULL, NULL);
1113 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1117 * gst_event_new_latency:
1118 * @latency: the new latency value
1120 * Create a new latency event. The event is sent upstream from the sinks and
1121 * notifies elements that they should add an additional @latency to the
1122 * running time before synchronising against the clock.
1124 * The latency is mostly used in live sinks and is always expressed in
1127 * Returns: (transfer full): a new #GstEvent
1132 gst_event_new_latency (GstClockTime latency)
1135 GstStructure *structure;
1137 GST_CAT_INFO (GST_CAT_EVENT,
1138 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1140 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1141 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1142 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1148 * gst_event_parse_latency:
1149 * @event: The event to query
1150 * @latency: (out): A pointer to store the latency in.
1152 * Get the latency in the latency event.
1157 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1159 g_return_if_fail (GST_IS_EVENT (event));
1160 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1164 g_value_get_uint64 (gst_structure_id_get_value (event->structure,
1165 GST_QUARK (LATENCY)));
1169 * gst_event_new_step:
1170 * @format: the format of @amount
1171 * @amount: the amount of data to step
1172 * @rate: the step rate
1173 * @flush: flushing steps
1174 * @intermediate: intermediate steps
1176 * Create a new step event. The purpose of the step event is to instruct a sink
1177 * to skip @amount (expressed in @format) of media. It can be used to implement
1178 * stepping through the video frame by frame or for doing fast trick modes.
1180 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1181 * = 0.0 or first reverse the direction of playback using a seek event to get
1182 * the same effect as rate < 0.0.
1184 * The @flush flag will clear any pending data in the pipeline before starting
1185 * the step operation.
1187 * The @intermediate flag instructs the pipeline that this step operation is
1188 * part of a larger step operation.
1190 * Returns: (transfer full): a new #GstEvent
1195 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1196 gboolean flush, gboolean intermediate)
1199 GstStructure *structure;
1201 g_return_val_if_fail (rate > 0.0, NULL);
1203 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1205 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1206 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1207 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1208 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1209 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1210 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1211 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1217 * gst_event_parse_step:
1218 * @event: The event to query
1219 * @format: (out) (allow-none): a pointer to store the format in
1220 * @amount: (out) (allow-none): a pointer to store the amount in
1221 * @rate: (out) (allow-none): a pointer to store the rate in
1222 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1223 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1226 * Parse the step event.
1231 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1232 gdouble * rate, gboolean * flush, gboolean * intermediate)
1234 const GstStructure *structure;
1236 g_return_if_fail (GST_IS_EVENT (event));
1237 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1239 structure = event->structure;
1242 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1243 GST_QUARK (FORMAT)));
1245 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1246 GST_QUARK (AMOUNT)));
1248 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1251 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1252 GST_QUARK (FLUSH)));
1254 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1255 GST_QUARK (INTERMEDIATE)));
1259 * gst_event_new_sink_message:
1260 * @msg: (transfer none): the #GstMessage to be posted
1262 * Create a new sink-message event. The purpose of the sink-message event is
1263 * to instruct a sink to post the message contained in the event synchronized
1266 * Returns: (transfer full): a new #GstEvent
1270 /* FIXME 0.11: take ownership of msg for consistency? */
1272 gst_event_new_sink_message (GstMessage * msg)
1275 GstStructure *structure;
1277 g_return_val_if_fail (msg != NULL, NULL);
1279 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1281 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1282 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1283 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1289 * gst_event_parse_sink_message:
1290 * @event: The event to query
1291 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1293 * Parse the sink-message event. Unref @msg after usage.
1298 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1300 g_return_if_fail (GST_IS_EVENT (event));
1301 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1305 GST_MESSAGE (gst_value_dup_mini_object (gst_structure_id_get_value
1306 (event->structure, GST_QUARK (MESSAGE))));
1310 * gst_event_new_toc:
1311 * @toc: #GstToc structure.
1312 * @updated: whether @toc was updated or not.
1314 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1315 * inform elements that some kind of the TOC was found.
1317 * Returns: a new #GstEvent.
1322 gst_event_new_toc (GstToc * toc, gboolean updated)
1324 GstStructure *toc_struct;
1326 g_return_val_if_fail (toc != NULL, NULL);
1328 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1330 toc_struct = priv_gst_toc_to_structure (toc);
1332 if (G_LIKELY (toc_struct != NULL)) {
1333 priv_gst_toc_structure_set_updated (toc_struct, updated);
1334 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1340 * gst_event_parse_toc:
1341 * @event: a TOC event.
1342 * @toc: (out): pointer to #GstToc structure.
1343 * @updated: (out): pointer to store TOC updated flag.
1345 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1350 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1352 const GstStructure *structure;
1354 g_return_if_fail (event != NULL);
1355 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1356 g_return_if_fail (toc != NULL);
1358 structure = gst_event_get_structure (event);
1359 *toc = priv_gst_toc_from_structure (structure);
1361 if (updated != NULL)
1362 *updated = priv_gst_toc_structure_get_updated (structure);
1366 * gst_event_new_toc_select:
1367 * @uid: UID in the TOC to start playback from.
1369 * Generate a TOC select event with the given @uid. The purpose of the
1370 * TOC select event is to start playback based on the TOC's entry with the
1373 * Returns: a new #GstEvent.
1378 gst_event_new_toc_select (const gchar * uid)
1380 GstStructure *structure;
1382 g_return_val_if_fail (uid != NULL, NULL);
1384 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1386 structure = gst_structure_id_new (GST_QUARK (EVENT_TOC_SELECT),
1387 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1389 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1393 * gst_event_parse_toc_select:
1394 * @event: a TOC select event.
1395 * @uid: (out): storage for the selection UID.
1397 * Parse a TOC select @event and store the results in the given @uid location.
1402 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1404 const GstStructure *structure;
1407 g_return_if_fail (event != NULL);
1408 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1410 structure = gst_event_get_structure (event);
1411 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1414 *uid = g_strdup (g_value_get_string (val));