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_BUFFERSIZE, "buffersize", 0},
118 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
119 {GST_EVENT_QOS, "qos", 0},
120 {GST_EVENT_SEEK, "seek", 0},
121 {GST_EVENT_NAVIGATION, "navigation", 0},
122 {GST_EVENT_LATENCY, "latency", 0},
123 {GST_EVENT_STEP, "step", 0},
124 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
125 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
126 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
127 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
128 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
134 * gst_event_type_get_name:
135 * @type: the event type
137 * Get a printable name for the given event type. Do not modify or free.
139 * Returns: a reference to the static name of the event.
142 gst_event_type_get_name (GstEventType type)
146 for (i = 0; event_quarks[i].name; i++) {
147 if (type == event_quarks[i].type)
148 return event_quarks[i].name;
154 * gst_event_type_to_quark:
155 * @type: the event type
157 * Get the unique quark for the given event type.
159 * Returns: the quark associated with the event type
162 gst_event_type_to_quark (GstEventType type)
166 for (i = 0; event_quarks[i].name; i++) {
167 if (type == event_quarks[i].type)
168 return event_quarks[i].quark;
174 * gst_event_type_get_flags:
175 * @type: a #GstEventType
177 * Gets the #GstEventTypeFlags associated with @type.
179 * Returns: a #GstEventTypeFlags.
182 gst_event_type_get_flags (GstEventType type)
184 GstEventTypeFlags ret;
186 ret = type & ((1 << GST_EVENT_TYPE_SHIFT) - 1);
195 for (i = 0; event_quarks[i].name; i++) { \
196 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name); \
200 G_DEFINE_TYPE_WITH_CODE (GstEvent, gst_event, GST_TYPE_MINI_OBJECT, _do_init);
203 gst_event_class_init (GstEventClass * klass)
205 parent_class = g_type_class_peek_parent (klass);
207 klass->mini_object_class.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
208 klass->mini_object_class.finalize =
209 (GstMiniObjectFinalizeFunction) gst_event_finalize;
213 gst_event_init (GstEvent * event)
215 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
219 gst_event_finalize (GstEvent * event)
221 g_return_if_fail (event != NULL);
222 g_return_if_fail (GST_IS_EVENT (event));
224 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
225 GST_EVENT_TYPE_NAME (event));
227 if (GST_EVENT_SRC (event)) {
228 gst_object_unref (GST_EVENT_SRC (event));
229 GST_EVENT_SRC (event) = NULL;
231 if (event->structure) {
232 gst_structure_set_parent_refcount (event->structure, NULL);
233 gst_structure_free (event->structure);
236 /* GST_MINI_OBJECT_CLASS (parent_class)->finalize (GST_MINI_OBJECT (event)); */
240 _gst_event_copy (GstEvent * event)
244 copy = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
246 GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
247 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
248 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
250 if (GST_EVENT_SRC (event)) {
251 GST_EVENT_SRC (copy) = gst_object_ref (GST_EVENT_SRC (event));
253 if (event->structure) {
254 copy->structure = gst_structure_copy (event->structure);
255 gst_structure_set_parent_refcount (copy->structure,
256 ©->mini_object.refcount);
262 gst_event_new (GstEventType type)
266 event = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
268 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
269 gst_event_type_get_name (type), type);
273 event->structure = NULL;
274 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
280 * gst_event_new_custom:
281 * @type: The type of the new event
282 * @structure: (transfer full): the structure for the event. The event will
283 * take ownership of the structure.
285 * Create a new custom-typed event. This can be used for anything not
286 * handled by other event-specific functions to pass an event to another
289 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
290 * assigning a free number and filling in the correct direction and
291 * serialization flags.
293 * New custom events can also be created by subclassing the event type if
296 * Returns: (transfer full): the new custom event.
299 gst_event_new_custom (GstEventType type, GstStructure * structure)
303 /* structure must not have a parent */
305 g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
307 event = gst_event_new (type);
309 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
310 event->structure = structure;
316 * gst_event_get_structure:
317 * @event: The #GstEvent.
319 * Access the structure of the event.
321 * Returns: The structure of the event. The structure is still
322 * owned by the event, which means that you should not free it and
323 * that the pointer becomes invalid when you free the event.
328 gst_event_get_structure (GstEvent * event)
330 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
332 return event->structure;
336 * gst_event_has_name:
337 * @event: The #GstEvent.
338 * @name: name to check
340 * Checks if @event has the given @name. This function is usually used to
341 * check the name of a custom event.
343 * Returns: %TRUE if @name matches the name of the event structure.
348 gst_event_has_name (GstEvent * event, const gchar * name)
350 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
352 if (event->structure == NULL)
355 return gst_structure_has_name (event->structure, name);
359 * gst_event_get_seqnum:
360 * @event: A #GstEvent.
362 * Retrieve the sequence number of a event.
364 * Events have ever-incrementing sequence numbers, which may also be set
365 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
366 * indicate that a event corresponds to some other set of events or messages,
367 * for example an EOS event corresponding to a SEEK event. It is considered good
368 * practice to make this correspondence when possible, though it is not
371 * Note that events and messages share the same sequence number incrementor;
372 * two events or messages will never have the same sequence number unless
373 * that correspondence was made explicitly.
375 * Returns: The event's sequence number.
382 gst_event_get_seqnum (GstEvent * event)
384 g_return_val_if_fail (GST_IS_EVENT (event), -1);
386 return GST_EVENT_SEQNUM (event);
390 * gst_event_set_seqnum:
391 * @event: A #GstEvent.
392 * @seqnum: A sequence number.
394 * Set the sequence number of a event.
396 * This function might be called by the creator of a event to indicate that the
397 * event relates to other events or messages. See gst_event_get_seqnum() for
405 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
407 g_return_if_fail (GST_IS_EVENT (event));
409 GST_EVENT_SEQNUM (event) = seqnum;
412 /* FIXME 0.11: It would be nice to have flush events
413 * that don't reset the running time in the sinks
417 * gst_event_new_flush_start:
419 * Allocate a new flush start event. The flush start event can be sent
420 * upstream and downstream and travels out-of-bounds with the dataflow.
422 * It marks pads as being flushing and will make them return
423 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
424 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
425 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
426 * on a flushing pad will return %FALSE immediately.
428 * Elements should unlock any blocking functions and exit their streaming
429 * functions as fast as possible when this event is received.
431 * This event is typically generated after a seek to flush out all queued data
432 * in the pipeline so that the new media is played as soon as possible.
434 * Returns: (transfer full): a new flush start event.
437 gst_event_new_flush_start (void)
439 return gst_event_new (GST_EVENT_FLUSH_START);
443 * gst_event_new_flush_stop:
445 * Allocate a new flush stop event. The flush stop event can be sent
446 * upstream and downstream and travels serialized with the dataflow.
447 * It is typically sent after sending a FLUSH_START event to make the
448 * pads accept data again.
450 * Elements can process this event synchronized with the dataflow since
451 * the preceeding FLUSH_START event stopped the dataflow.
453 * This event is typically generated to complete a seek and to resume
456 * Returns: (transfer full): a new flush stop event.
459 gst_event_new_flush_stop (void)
461 return gst_event_new (GST_EVENT_FLUSH_STOP);
467 * Create a new EOS event. The eos event can only travel downstream
468 * synchronized with the buffer flow. Elements that receive the EOS
469 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
470 * when data after the EOS event arrives.
472 * The EOS event will travel down to the sink elements in the pipeline
473 * which will then post the #GST_MESSAGE_EOS on the bus after they have
474 * finished playing any buffered data.
476 * When all sinks have posted an EOS message, an EOS message is
477 * forwarded to the application.
479 * The EOS event itself will not cause any state transitions of the pipeline.
481 * Returns: (transfer full): the new EOS event.
484 gst_event_new_eos (void)
486 return gst_event_new (GST_EVENT_EOS);
490 * gst_event_new_new_segment:
491 * @update: is this segment an update to a previous one
492 * @rate: a new rate for playback
493 * @format: The format of the segment values
494 * @start: the start value of the segment
495 * @stop: the stop value of the segment
496 * @position: stream position
498 * Allocate a new newsegment event with the given format/values tripplets
500 * This method calls gst_event_new_new_segment_full() passing a default
501 * value of 1.0 for applied_rate
503 * Returns: (transfer full): a new newsegment event.
506 gst_event_new_new_segment (gboolean update, gdouble rate, GstFormat format,
507 gint64 start, gint64 stop, gint64 position)
509 return gst_event_new_new_segment_full (update, rate, 1.0, format, start,
514 * gst_event_parse_new_segment:
515 * @event: The event to query
516 * @update: (out): A pointer to the update flag of the segment
517 * @rate: (out): A pointer to the rate of the segment
518 * @format: (out): A pointer to the format of the newsegment values
519 * @start: (out): A pointer to store the start value in
520 * @stop: (out): A pointer to store the stop value in
521 * @position: (out): A pointer to store the stream time in
523 * Get the update flag, rate, format, start, stop and position in the
524 * newsegment event. In general, gst_event_parse_new_segment_full() should
525 * be used instead of this, to also retrieve the applied_rate value of the
526 * segment. See gst_event_new_new_segment_full() for a full description
527 * of the newsegment event.
530 gst_event_parse_new_segment (GstEvent * event, gboolean * update,
531 gdouble * rate, GstFormat * format, gint64 * start,
532 gint64 * stop, gint64 * position)
534 gst_event_parse_new_segment_full (event, update, rate, NULL, format, start,
539 * gst_event_new_new_segment_full:
540 * @update: Whether this segment is an update to a previous one
541 * @rate: A new rate for playback
542 * @applied_rate: The rate factor which has already been applied
543 * @format: The format of the segment values
544 * @start: The start value of the segment
545 * @stop: The stop value of the segment
546 * @position: stream position
548 * Allocate a new newsegment event with the given format/values triplets.
550 * The newsegment event marks the range of buffers to be processed. All
551 * data not within the segment range is not to be processed. This can be
552 * used intelligently by plugins to apply more efficient methods of skipping
553 * unneeded data. The valid range is expressed with the @start and @stop
556 * The position value of the segment is used in conjunction with the start
557 * value to convert the buffer timestamps into the stream time. This is
558 * usually done in sinks to report the current stream_time.
559 * @position represents the stream_time of a buffer carrying a timestamp of
560 * @start. @position cannot be -1.
562 * @start cannot be -1, @stop can be -1. If there
563 * is a valid @stop given, it must be greater or equal the @start, including
564 * when the indicated playback @rate is < 0.
566 * The @applied_rate value provides information about any rate adjustment that
567 * has already been made to the timestamps and content on the buffers of the
568 * stream. (@rate * @applied_rate) should always equal the rate that has been
569 * requested for playback. For example, if an element has an input segment
570 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
571 * incoming timestamps and buffer content by half and output a newsegment event
572 * with @rate of 1.0 and @applied_rate of 2.0
574 * After a newsegment event, the buffer stream time is calculated with:
576 * position + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
578 * Returns: (transfer full): a new newsegment event.
583 gst_event_new_new_segment_full (gboolean update, gdouble rate,
584 gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
588 GstStructure *structure;
590 g_return_val_if_fail (rate != 0.0, NULL);
591 g_return_val_if_fail (applied_rate != 0.0, NULL);
592 g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, NULL);
594 if (format == GST_FORMAT_TIME) {
595 GST_CAT_INFO (GST_CAT_EVENT,
596 "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
597 "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
598 ", position %" GST_TIME_FORMAT,
599 update, rate, GST_TIME_ARGS (start),
600 GST_TIME_ARGS (stop), GST_TIME_ARGS (position));
602 GST_CAT_INFO (GST_CAT_EVENT,
603 "creating newsegment update %d, rate %lf, format %s, "
604 "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", position %"
605 G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
609 g_return_val_if_fail (position != -1, NULL);
610 g_return_val_if_fail (start != -1, NULL);
612 g_return_val_if_fail (start <= stop, NULL);
614 structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
615 GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
616 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
617 GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
618 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
619 GST_QUARK (START), G_TYPE_INT64, start,
620 GST_QUARK (STOP), G_TYPE_INT64, stop,
621 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
622 event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
628 * gst_event_parse_new_segment_full:
629 * @event: The event to query
630 * @update: (out): A pointer to the update flag of the segment
631 * @rate: (out): A pointer to the rate of the segment
632 * @applied_rate: (out): A pointer to the applied_rate of the segment
633 * @format: (out): A pointer to the format of the newsegment values
634 * @start: (out): A pointer to store the start value in
635 * @stop: (out): A pointer to store the stop value in
636 * @position: (out): A pointer to store the stream time in
638 * Get the update, rate, applied_rate, format, start, stop and
639 * position in the newsegment event. See gst_event_new_new_segment_full()
640 * for a full description of the newsegment event.
645 gst_event_parse_new_segment_full (GstEvent * event, gboolean * update,
646 gdouble * rate, gdouble * applied_rate, GstFormat * format,
647 gint64 * start, gint64 * stop, gint64 * position)
649 const GstStructure *structure;
651 g_return_if_fail (GST_IS_EVENT (event));
652 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
654 structure = event->structure;
655 if (G_LIKELY (update))
657 g_value_get_boolean (gst_structure_id_get_value (structure,
658 GST_QUARK (UPDATE)));
661 g_value_get_double (gst_structure_id_get_value (structure,
663 if (G_LIKELY (applied_rate))
665 g_value_get_double (gst_structure_id_get_value (structure,
666 GST_QUARK (APPLIED_RATE)));
667 if (G_LIKELY (format))
668 *format = (GstFormat)
669 g_value_get_enum (gst_structure_id_get_value (structure,
670 GST_QUARK (FORMAT)));
671 if (G_LIKELY (start))
673 g_value_get_int64 (gst_structure_id_get_value (structure,
677 g_value_get_int64 (gst_structure_id_get_value (structure,
679 if (G_LIKELY (position))
681 g_value_get_int64 (gst_structure_id_get_value (structure,
682 GST_QUARK (POSITION)));
687 * @taglist: (transfer full): metadata list. The event will take ownership
690 * Generates a metadata tag event from the given @taglist.
692 * Returns: (transfer full): a new #GstEvent
695 gst_event_new_tag (GstTagList * taglist)
697 g_return_val_if_fail (taglist != NULL, NULL);
699 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
703 * gst_event_parse_tag:
704 * @event: a tag event
705 * @taglist: (out) (transfer none): pointer to metadata list
707 * Parses a tag @event and stores the results in the given @taglist location.
708 * No reference to the taglist will be returned, it remains valid only until
709 * the @event is freed. Don't modify or free the taglist, make a copy if you
710 * want to modify it or store it for later use.
713 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
715 g_return_if_fail (GST_IS_EVENT (event));
716 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
719 *taglist = (GstTagList *) event->structure;
722 /* buffersize event */
724 * gst_event_new_buffer_size:
725 * @format: buffer format
726 * @minsize: minimum buffer size
727 * @maxsize: maximum buffer size
728 * @async: thread behavior
730 * Create a new buffersize event. The event is sent downstream and notifies
731 * elements that they should provide a buffer of the specified dimensions.
733 * When the @async flag is set, a thread boundary is preferred.
735 * Returns: (transfer full): a new #GstEvent
738 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
739 gint64 maxsize, gboolean async)
742 GstStructure *structure;
744 GST_CAT_INFO (GST_CAT_EVENT,
745 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
746 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
747 minsize, maxsize, async);
749 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
750 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
751 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
752 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
753 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
754 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
760 * gst_event_parse_buffer_size:
761 * @event: The event to query
762 * @format: (out): A pointer to store the format in
763 * @minsize: (out): A pointer to store the minsize in
764 * @maxsize: (out): A pointer to store the maxsize in
765 * @async: (out): A pointer to store the async-flag in
767 * Get the format, minsize, maxsize and async-flag in the buffersize event.
770 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
771 gint64 * minsize, gint64 * maxsize, gboolean * async)
773 const GstStructure *structure;
775 g_return_if_fail (GST_IS_EVENT (event));
776 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
778 structure = event->structure;
780 *format = (GstFormat)
781 g_value_get_enum (gst_structure_id_get_value (structure,
782 GST_QUARK (FORMAT)));
785 g_value_get_int64 (gst_structure_id_get_value (structure,
786 GST_QUARK (MINSIZE)));
789 g_value_get_int64 (gst_structure_id_get_value (structure,
790 GST_QUARK (MAXSIZE)));
793 g_value_get_boolean (gst_structure_id_get_value (structure,
799 * @proportion: the proportion of the qos message
800 * @diff: The time difference of the last Clock sync
801 * @timestamp: The timestamp of the buffer
803 * Allocate a new qos event with the given values. This function calls
804 * gst_event_new_qos_full() with the type set to #GST_QOS_TYPE_OVERFLOW
805 * when diff is negative (buffers are in time) and #GST_QOS_TYPE_UNDERFLOW
806 * when @diff is positive (buffers are late).
808 * Returns: (transfer full): a new QOS event.
811 gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
812 GstClockTime timestamp)
817 type = GST_QOS_TYPE_OVERFLOW;
819 type = GST_QOS_TYPE_UNDERFLOW;
821 return gst_event_new_qos_full (type, proportion, diff, timestamp);
825 * gst_event_new_qos_full:
826 * @type: the QoS type
827 * @proportion: the proportion of the qos message
828 * @diff: The time difference of the last Clock sync
829 * @timestamp: The timestamp of the buffer
831 * Allocate a new qos event with the given values.
832 * The QOS event is generated in an element that wants an upstream
833 * element to either reduce or increase its rate because of
834 * high/low CPU load or other resource usage such as network performance or
835 * throttling. Typically sinks generate these events for each buffer
838 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
839 * used when a buffer arrived in time or when the sink cannot keep up with
840 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
841 * receiving buffers fast enough and thus has to drop late buffers.
842 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
843 * by the application, for example to reduce power consumption.
845 * @proportion indicates the real-time performance of the streaming in the
846 * element that generated the QoS event (usually the sink). The value is
847 * generally computed based on more long term statistics about the streams
848 * timestamps compared to the clock.
849 * A value < 1.0 indicates that the upstream element is producing data faster
850 * than real-time. A value > 1.0 indicates that the upstream element is not
851 * producing data fast enough. 1.0 is the ideal @proportion value. The
852 * proportion value can safely be used to lower or increase the quality of
855 * @diff is the difference against the clock in running time of the last
856 * buffer that caused the element to generate the QOS event. A negative value
857 * means that the buffer with @timestamp arrived in time. A positive value
858 * indicates how late the buffer with @timestamp was. When throttling is
859 * enabled, @diff will be set to the requested throttling interval.
861 * @timestamp is the timestamp of the last buffer that cause the element
862 * to generate the QOS event. It is expressed in running time and thus an ever
865 * The upstream element can use the @diff and @timestamp values to decide
866 * whether to process more buffers. For possitive @diff, all buffers with
867 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
868 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
869 * result smaller than 0 is not allowed.
871 * The application can use general event probes to intercept the QoS
872 * event and implement custom application specific QoS handling.
874 * Returns: (transfer full): a new QOS event.
879 gst_event_new_qos_full (GstQOSType type, gdouble proportion,
880 GstClockTimeDiff diff, GstClockTime timestamp)
883 GstStructure *structure;
885 /* diff must be positive or timestamp + diff must be positive */
886 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
888 GST_CAT_INFO (GST_CAT_EVENT,
889 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
890 ", timestamp %" GST_TIME_FORMAT, type, proportion,
891 diff, GST_TIME_ARGS (timestamp));
893 structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
894 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
895 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
896 GST_QUARK (DIFF), G_TYPE_INT64, diff,
897 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
898 event = gst_event_new_custom (GST_EVENT_QOS, structure);
904 * gst_event_parse_qos:
905 * @event: The event to query
906 * @proportion: (out): A pointer to store the proportion in
907 * @diff: (out): A pointer to store the diff in
908 * @timestamp: (out): A pointer to store the timestamp in
910 * Get the proportion, diff and timestamp in the qos event. See
911 * gst_event_new_qos() for more information about the different QoS values.
914 gst_event_parse_qos (GstEvent * event, gdouble * proportion,
915 GstClockTimeDiff * diff, GstClockTime * timestamp)
917 gst_event_parse_qos_full (event, NULL, proportion, diff, timestamp);
921 * gst_event_parse_qos_full:
922 * @event: The event to query
923 * @type: (out): A pointer to store the QoS type in
924 * @proportion: (out): A pointer to store the proportion in
925 * @diff: (out): A pointer to store the diff in
926 * @timestamp: (out): A pointer to store the timestamp in
928 * Get the type, proportion, diff and timestamp in the qos event. See
929 * gst_event_new_qos_full() for more information about the different QoS values.
934 gst_event_parse_qos_full (GstEvent * event, GstQOSType * type,
935 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
937 const GstStructure *structure;
939 g_return_if_fail (GST_IS_EVENT (event));
940 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
942 structure = event->structure;
945 g_value_get_enum (gst_structure_id_get_value (structure,
949 g_value_get_double (gst_structure_id_get_value (structure,
950 GST_QUARK (PROPORTION)));
953 g_value_get_int64 (gst_structure_id_get_value (structure,
957 g_value_get_uint64 (gst_structure_id_get_value (structure,
958 GST_QUARK (TIMESTAMP)));
962 * gst_event_new_seek:
963 * @rate: The new playback rate
964 * @format: The format of the seek values
965 * @flags: The optional seek flags
966 * @start_type: The type and flags for the new start position
967 * @start: The value of the new start position
968 * @stop_type: The type and flags for the new stop position
969 * @stop: The value of the new stop position
971 * Allocate a new seek event with the given parameters.
973 * The seek event configures playback of the pipeline between @start to @stop
974 * at the speed given in @rate, also called a playback segment.
975 * The @start and @stop values are expressed in @format.
977 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
978 * Negatives values means backwards playback. A value of 0.0 for the
979 * rate is not allowed and should be accomplished instead by PAUSING the
982 * A pipeline has a default playback segment configured with a start
983 * position of 0, a stop position of -1 and a rate of 1.0. The currently
984 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
986 * @start_type and @stop_type specify how to adjust the currently configured
987 * start and stop fields in playback segment. Adjustments can be made relative
988 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
989 * means that the position should not be updated.
991 * When the rate is positive and @start has been updated, playback will start
992 * from the newly configured start position.
994 * For negative rates, playback will start from the newly configured stop
995 * position (if any). If the stop position if updated, it must be different from
996 * -1 for negative rates.
998 * It is not possible to seek relative to the current playback position, to do
999 * this, PAUSE the pipeline, query the current playback position with
1000 * #GST_QUERY_POSITION and update the playback segment current position with a
1001 * #GST_SEEK_TYPE_SET to the desired position.
1003 * Returns: (transfer full): a new seek event.
1006 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1007 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1010 GstStructure *structure;
1012 g_return_val_if_fail (rate != 0.0, NULL);
1014 if (format == GST_FORMAT_TIME) {
1015 GST_CAT_INFO (GST_CAT_EVENT,
1016 "creating seek rate %lf, format TIME, flags %d, "
1017 "start_type %d, start %" GST_TIME_FORMAT ", "
1018 "stop_type %d, stop %" GST_TIME_FORMAT,
1019 rate, flags, start_type, GST_TIME_ARGS (start),
1020 stop_type, GST_TIME_ARGS (stop));
1022 GST_CAT_INFO (GST_CAT_EVENT,
1023 "creating seek rate %lf, format %s, flags %d, "
1024 "start_type %d, start %" G_GINT64_FORMAT ", "
1025 "stop_type %d, stop %" G_GINT64_FORMAT,
1026 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1030 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1031 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1032 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1033 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1034 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1035 GST_QUARK (CUR), G_TYPE_INT64, start,
1036 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1037 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1038 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1044 * gst_event_parse_seek:
1045 * @event: a seek event
1046 * @rate: (out): result location for the rate
1047 * @format: (out): result location for the stream format
1048 * @flags: (out): result location for the #GstSeekFlags
1049 * @start_type: (out): result location for the #GstSeekType of the start position
1050 * @start: (out): result location for the start postion expressed in @format
1051 * @stop_type: (out): result location for the #GstSeekType of the stop position
1052 * @stop: (out): result location for the stop postion expressed in @format
1054 * Parses a seek @event and stores the results in the given result locations.
1057 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1058 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1059 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1061 const GstStructure *structure;
1063 g_return_if_fail (GST_IS_EVENT (event));
1064 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1066 structure = event->structure;
1069 g_value_get_double (gst_structure_id_get_value (structure,
1072 *format = (GstFormat)
1073 g_value_get_enum (gst_structure_id_get_value (structure,
1074 GST_QUARK (FORMAT)));
1076 *flags = (GstSeekFlags)
1077 g_value_get_flags (gst_structure_id_get_value (structure,
1078 GST_QUARK (FLAGS)));
1080 *start_type = (GstSeekType)
1081 g_value_get_enum (gst_structure_id_get_value (structure,
1082 GST_QUARK (CUR_TYPE)));
1085 g_value_get_int64 (gst_structure_id_get_value (structure,
1088 *stop_type = (GstSeekType)
1089 g_value_get_enum (gst_structure_id_get_value (structure,
1090 GST_QUARK (STOP_TYPE)));
1093 g_value_get_int64 (gst_structure_id_get_value (structure,
1098 * gst_event_new_navigation:
1099 * @structure: (transfer full): description of the event. The event will take
1100 * ownership of the structure.
1102 * Create a new navigation event from the given description.
1104 * Returns: (transfer full): a new #GstEvent
1107 gst_event_new_navigation (GstStructure * structure)
1109 g_return_val_if_fail (structure != NULL, NULL);
1111 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1115 * gst_event_new_latency:
1116 * @latency: the new latency value
1118 * Create a new latency event. The event is sent upstream from the sinks and
1119 * notifies elements that they should add an additional @latency to the
1120 * running time before synchronising against the clock.
1122 * The latency is mostly used in live sinks and is always expressed in
1125 * Returns: (transfer full): a new #GstEvent
1130 gst_event_new_latency (GstClockTime latency)
1133 GstStructure *structure;
1135 GST_CAT_INFO (GST_CAT_EVENT,
1136 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1138 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1139 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1140 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1146 * gst_event_parse_latency:
1147 * @event: The event to query
1148 * @latency: (out): A pointer to store the latency in.
1150 * Get the latency in the latency event.
1155 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1157 g_return_if_fail (GST_IS_EVENT (event));
1158 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1162 g_value_get_uint64 (gst_structure_id_get_value (event->structure,
1163 GST_QUARK (LATENCY)));
1167 * gst_event_new_step:
1168 * @format: the format of @amount
1169 * @amount: the amount of data to step
1170 * @rate: the step rate
1171 * @flush: flushing steps
1172 * @intermediate: intermediate steps
1174 * Create a new step event. The purpose of the step event is to instruct a sink
1175 * to skip @amount (expressed in @format) of media. It can be used to implement
1176 * stepping through the video frame by frame or for doing fast trick modes.
1178 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1179 * = 0.0 or first reverse the direction of playback using a seek event to get
1180 * the same effect as rate < 0.0.
1182 * The @flush flag will clear any pending data in the pipeline before starting
1183 * the step operation.
1185 * The @intermediate flag instructs the pipeline that this step operation is
1186 * part of a larger step operation.
1188 * Returns: (transfer full): a new #GstEvent
1193 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1194 gboolean flush, gboolean intermediate)
1197 GstStructure *structure;
1199 g_return_val_if_fail (rate > 0.0, NULL);
1201 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1203 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1204 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1205 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1206 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1207 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1208 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1209 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1215 * gst_event_parse_step:
1216 * @event: The event to query
1217 * @format: (out) (allow-none): a pointer to store the format in
1218 * @amount: (out) (allow-none): a pointer to store the amount in
1219 * @rate: (out) (allow-none): a pointer to store the rate in
1220 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1221 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1224 * Parse the step event.
1229 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1230 gdouble * rate, gboolean * flush, gboolean * intermediate)
1232 const GstStructure *structure;
1234 g_return_if_fail (GST_IS_EVENT (event));
1235 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1237 structure = event->structure;
1240 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1241 GST_QUARK (FORMAT)));
1243 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1244 GST_QUARK (AMOUNT)));
1246 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1249 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1250 GST_QUARK (FLUSH)));
1252 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1253 GST_QUARK (INTERMEDIATE)));
1257 * gst_event_new_sink_message:
1258 * @msg: (transfer none): the #GstMessage to be posted
1260 * Create a new sink-message event. The purpose of the sink-message event is
1261 * to instruct a sink to post the message contained in the event synchronized
1264 * Returns: (transfer full): a new #GstEvent
1268 /* FIXME 0.11: take ownership of msg for consistency? */
1270 gst_event_new_sink_message (GstMessage * msg)
1273 GstStructure *structure;
1275 g_return_val_if_fail (msg != NULL, NULL);
1277 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1279 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1280 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1281 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1287 * gst_event_parse_sink_message:
1288 * @event: The event to query
1289 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1291 * Parse the sink-message event. Unref @msg after usage.
1296 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1298 g_return_if_fail (GST_IS_EVENT (event));
1299 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1303 GST_MESSAGE (gst_value_dup_mini_object (gst_structure_id_get_value
1304 (event->structure, GST_QUARK (MESSAGE))));