2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wim.taymans@chello.be>
4 * 2005 Wim Taymans <wim@fluendo.com>
6 * gstevent.c: GstEvent subsystem
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
26 * @short_description: Structure describing events that are passed up and down
28 * @see_also: #GstPad, #GstElement
30 * The event class provides factory methods to construct events for sending
31 * and functions to query (parse) received events.
33 * Events are usually created with gst_event_new_*() which takes event-type
34 * specific parameters as arguments.
35 * To send an event application will usually use gst_element_send_event() and
36 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 * The event should be unreffed with gst_event_unref() if it has not been sent.
39 * Events that have been received can be parsed with their respective
40 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
42 * Events are passed between elements in parallel to the data stream. Some events
43 * are serialized with buffers, others are not. Some events only travel downstream,
44 * others only upstream. Some events can travel both upstream and downstream.
46 * The events are used to signal special conditions in the datastream such as
47 * EOS (end of stream) or the start of a new stream-segment.
48 * Events are also used to flush the pipeline of any pending data.
50 * Most of the event API is used inside plugins. Applications usually only
51 * construct and use seek events.
52 * To do that gst_event_new_seek() is used to create a seek event. It takes
53 * the needed parameters to specity seeking time and mode.
55 * <title>performing a seek on a pipeline</title>
60 * // construct a seek event to play the media from second 2 to 5, flush
61 * // the pipeline to decrease latency.
62 * event = gst_event_new_seek (1.0,
64 * GST_SEEK_FLAG_FLUSH,
65 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
66 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
68 * result = gst_element_send_event (pipeline, event);
70 * g_warning ("seek failed");
75 * Last reviewed on 2006-09-6 (0.10.10)
79 #include "gst_private.h"
80 #include <string.h> /* memcpy */
84 #include "gstenumtypes.h"
88 static GType _gst_event_type = 0;
97 static GstEventQuarks event_quarks[] = {
98 {GST_EVENT_UNKNOWN, "unknown", 0},
99 {GST_EVENT_FLUSH_START, "flush-start", 0},
100 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
101 {GST_EVENT_EOS, "eos", 0},
102 {GST_EVENT_NEWSEGMENT, "newsegment", 0},
103 {GST_EVENT_TAG, "tag", 0},
104 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
105 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
106 {GST_EVENT_QOS, "qos", 0},
107 {GST_EVENT_SEEK, "seek", 0},
108 {GST_EVENT_NAVIGATION, "navigation", 0},
109 {GST_EVENT_LATENCY, "latency", 0},
110 {GST_EVENT_STEP, "step", 0},
111 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
112 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
113 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
114 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
115 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
121 _gst_event_initialize (void)
125 gst_event_get_type ();
126 g_type_class_ref (gst_seek_flags_get_type ());
127 g_type_class_ref (gst_seek_type_get_type ());
129 for (i = 0; event_quarks[i].name; i++) {
130 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
135 * gst_event_type_get_name:
136 * @type: the event type
138 * Get a printable name for the given event type. Do not modify or free.
140 * Returns: a reference to the static name of the event.
143 gst_event_type_get_name (GstEventType type)
147 for (i = 0; event_quarks[i].name; i++) {
148 if (type == event_quarks[i].type)
149 return event_quarks[i].name;
155 * gst_event_type_to_quark:
156 * @type: the event type
158 * Get the unique quark for the given event type.
160 * Returns: the quark associated with the event type
163 gst_event_type_to_quark (GstEventType type)
167 for (i = 0; event_quarks[i].name; i++) {
168 if (type == event_quarks[i].type)
169 return event_quarks[i].quark;
175 * gst_event_type_get_flags:
176 * @type: a #GstEventType
178 * Gets the #GstEventTypeFlags associated with @type.
180 * Returns: a #GstEventTypeFlags.
183 gst_event_type_get_flags (GstEventType type)
185 GstEventTypeFlags ret;
187 ret = type & ((1 << GST_EVENT_STICKY_SHIFT) - 1);
193 gst_event_get_type (void)
195 if (G_UNLIKELY (_gst_event_type == 0)) {
196 _gst_event_type = gst_mini_object_register ("GstEvent");
198 return _gst_event_type;
202 _gst_event_free (GstEvent * event)
204 g_return_if_fail (event != NULL);
205 g_return_if_fail (GST_IS_EVENT (event));
207 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
208 GST_EVENT_TYPE_NAME (event));
210 if (event->structure) {
211 gst_structure_set_parent_refcount (event->structure, NULL);
212 gst_structure_free (event->structure);
215 g_slice_free1 (GST_MINI_OBJECT_SIZE (event), event);
218 static void gst_event_init (GstEvent * event, gsize size, GstEventType type);
221 _gst_event_copy (GstEvent * event)
225 copy = g_slice_new0 (GstEvent);
227 gst_event_init (copy, sizeof (GstEvent), GST_EVENT_TYPE (event));
229 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
230 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
232 if (event->structure) {
233 copy->structure = gst_structure_copy (event->structure);
234 gst_structure_set_parent_refcount (copy->structure,
235 ©->mini_object.refcount);
241 gst_event_init (GstEvent * event, gsize size, GstEventType type)
243 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type, size);
245 event->mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
246 event->mini_object.free = (GstMiniObjectFreeFunction) _gst_event_free;
248 GST_EVENT_TYPE (event) = type;
249 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
250 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
254 gst_event_new (GstEventType type)
258 event = g_slice_new0 (GstEvent);
260 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
261 gst_event_type_get_name (type), type);
263 gst_event_init (event, sizeof (GstEvent), type);
269 * gst_event_new_custom:
270 * @type: The type of the new event
271 * @structure: (transfer full): the structure for the event. The event will
272 * take ownership of the structure.
274 * Create a new custom-typed event. This can be used for anything not
275 * handled by other event-specific functions to pass an event to another
278 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
279 * assigning a free number and filling in the correct direction and
280 * serialization flags.
282 * New custom events can also be created by subclassing the event type if
285 * Returns: (transfer full): the new custom event.
288 gst_event_new_custom (GstEventType type, GstStructure * structure)
292 /* structure must not have a parent */
294 g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
296 event = gst_event_new (type);
298 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
299 event->structure = structure;
305 * gst_event_get_structure:
306 * @event: The #GstEvent.
308 * Access the structure of the event.
310 * Returns: The structure of the event. The structure is still
311 * owned by the event, which means that you should not free it and
312 * that the pointer becomes invalid when you free the event.
317 gst_event_get_structure (GstEvent * event)
319 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
321 return event->structure;
325 * gst_event_has_name:
326 * @event: The #GstEvent.
327 * @name: name to check
329 * Checks if @event has the given @name. This function is usually used to
330 * check the name of a custom event.
332 * Returns: %TRUE if @name matches the name of the event structure.
337 gst_event_has_name (GstEvent * event, const gchar * name)
339 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
341 if (event->structure == NULL)
344 return gst_structure_has_name (event->structure, name);
348 * gst_event_get_seqnum:
349 * @event: A #GstEvent.
351 * Retrieve the sequence number of a event.
353 * Events have ever-incrementing sequence numbers, which may also be set
354 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
355 * indicate that a event corresponds to some other set of events or messages,
356 * for example an EOS event corresponding to a SEEK event. It is considered good
357 * practice to make this correspondence when possible, though it is not
360 * Note that events and messages share the same sequence number incrementor;
361 * two events or messages will never not have the same sequence number unless
362 * that correspondence was made explicitly.
364 * Returns: The event's sequence number.
371 gst_event_get_seqnum (GstEvent * event)
373 g_return_val_if_fail (GST_IS_EVENT (event), -1);
375 return GST_EVENT_SEQNUM (event);
379 * gst_event_set_seqnum:
380 * @event: A #GstEvent.
381 * @seqnum: A sequence number.
383 * Set the sequence number of a event.
385 * This function might be called by the creator of a event to indicate that the
386 * event relates to other events or messages. See gst_event_get_seqnum() for
394 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
396 g_return_if_fail (GST_IS_EVENT (event));
398 GST_EVENT_SEQNUM (event) = seqnum;
401 /* FIXME 0.11: It would be nice to have flush events
402 * that don't reset the running time in the sinks
406 * gst_event_new_flush_start:
408 * Allocate a new flush start event. The flush start event can be sent
409 * upstream and downstream and travels out-of-bounds with the dataflow.
411 * It marks pads as being flushing and will make them return
412 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
413 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
414 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
415 * on a flushing pad will return %FALSE immediately.
417 * Elements should unlock any blocking functions and exit their streaming
418 * functions as fast as possible when this event is received.
420 * This event is typically generated after a seek to flush out all queued data
421 * in the pipeline so that the new media is played as soon as possible.
423 * Returns: (transfer full): a new flush start event.
426 gst_event_new_flush_start (void)
428 return gst_event_new (GST_EVENT_FLUSH_START);
432 * gst_event_new_flush_stop:
434 * Allocate a new flush stop event. The flush stop event can be sent
435 * upstream and downstream and travels serialized with the dataflow.
436 * It is typically sent after sending a FLUSH_START event to make the
437 * pads accept data again.
439 * Elements can process this event synchronized with the dataflow since
440 * the preceeding FLUSH_START event stopped the dataflow.
442 * This event is typically generated to complete a seek and to resume
445 * Returns: (transfer full): a new flush stop event.
448 gst_event_new_flush_stop (void)
450 return gst_event_new (GST_EVENT_FLUSH_STOP);
456 * Create a new EOS event. The eos event can only travel downstream
457 * synchronized with the buffer flow. Elements that receive the EOS
458 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
459 * when data after the EOS event arrives.
461 * The EOS event will travel down to the sink elements in the pipeline
462 * which will then post the #GST_MESSAGE_EOS on the bus after they have
463 * finished playing any buffered data.
465 * When all sinks have posted an EOS message, an EOS message is
466 * forwarded to the application.
468 * The EOS event itself will not cause any state transitions of the pipeline.
470 * Returns: (transfer full): the new EOS event.
473 gst_event_new_eos (void)
475 return gst_event_new (GST_EVENT_EOS);
479 * gst_event_new_new_segment:
480 * @update: is this segment an update to a previous one
481 * @rate: a new rate for playback
482 * @format: The format of the segment values
483 * @start: the start value of the segment
484 * @stop: the stop value of the segment
485 * @time: the time value of the segment
487 * Allocate a new newsegment event with the given format/values tripplets
489 * This method calls gst_event_new_new_segment_full() passing a default
490 * value of 1.0 for applied_rate
492 * Returns: (transfer full): a new newsegment event.
495 gst_event_new_new_segment (gboolean update, gdouble rate, GstFormat format,
496 gint64 start, gint64 stop, gint64 time)
498 return gst_event_new_new_segment_full (update, rate, 1.0, format, start,
503 * gst_event_parse_new_segment:
504 * @event: The event to query
505 * @update: (out): A pointer to the update flag of the segment
506 * @rate: (out): A pointer to the rate of the segment
507 * @format: (out): A pointer to the format of the newsegment values
508 * @start: (out): A pointer to store the start value in
509 * @stop: (out): A pointer to store the stop value in
510 * @time: (out): A pointer to store the time value in
512 * Get the update flag, rate, format, start, stop and time in the
513 * newsegment event. In general, gst_event_parse_new_segment_full() should
514 * be used instead of this, to also retrieve the applied_rate value of the
515 * segment. See gst_event_new_new_segment_full() for a full description
516 * of the newsegment event.
519 gst_event_parse_new_segment (GstEvent * event, gboolean * update,
520 gdouble * rate, GstFormat * format, gint64 * start,
521 gint64 * stop, gint64 * time)
523 gst_event_parse_new_segment_full (event, update, rate, NULL, format, start,
528 * gst_event_new_new_segment_full:
529 * @update: Whether this segment is an update to a previous one
530 * @rate: A new rate for playback
531 * @applied_rate: The rate factor which has already been applied
532 * @format: The format of the segment values
533 * @start: The start value of the segment
534 * @stop: The stop value of the segment
535 * @time: the time value of the segment
537 * Allocate a new newsegment event with the given format/values triplets.
539 * The newsegment event marks the range of buffers to be processed. All
540 * data not within the segment range is not to be processed. This can be
541 * used intelligently by plugins to apply more efficient methods of skipping
542 * unneeded data. The valid range is expressed with the @start and @stop
545 * The time value of the segment is used in conjunction with the start
546 * value to convert the buffer timestamps into the stream time. This is
547 * usually done in sinks to report the current stream_time.
548 * @time represents the stream_time of a buffer carrying a timestamp of
549 * @start. @time cannot be -1.
551 * @start cannot be -1, @stop can be -1. If there
552 * is a valid @stop given, it must be greater or equal the @start, including
553 * when the indicated playback @rate is < 0.
555 * The @applied_rate value provides information about any rate adjustment that
556 * has already been made to the timestamps and content on the buffers of the
557 * stream. (@rate * @applied_rate) should always equal the rate that has been
558 * requested for playback. For example, if an element has an input segment
559 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
560 * incoming timestamps and buffer content by half and output a newsegment event
561 * with @rate of 1.0 and @applied_rate of 2.0
563 * After a newsegment event, the buffer stream time is calculated with:
565 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
567 * Returns: (transfer full): a new newsegment event.
572 gst_event_new_new_segment_full (gboolean update, gdouble rate,
573 gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
577 GstStructure *structure;
579 g_return_val_if_fail (rate != 0.0, NULL);
580 g_return_val_if_fail (applied_rate != 0.0, NULL);
582 if (format == GST_FORMAT_TIME) {
583 GST_CAT_INFO (GST_CAT_EVENT,
584 "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
585 "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
586 ", time %" GST_TIME_FORMAT,
587 update, rate, GST_TIME_ARGS (start),
588 GST_TIME_ARGS (stop), GST_TIME_ARGS (time));
590 GST_CAT_INFO (GST_CAT_EVENT,
591 "creating newsegment update %d, rate %lf, format %s, "
592 "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", time %"
593 G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
597 g_return_val_if_fail (time != -1, NULL);
598 g_return_val_if_fail (start != -1, NULL);
600 g_return_val_if_fail (start <= stop, NULL);
602 structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
603 GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
604 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
605 GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
606 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
607 GST_QUARK (START), G_TYPE_INT64, start,
608 GST_QUARK (STOP), G_TYPE_INT64, stop,
609 GST_QUARK (TIME), G_TYPE_INT64, time, NULL);
610 event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
616 * gst_event_parse_new_segment_full:
617 * @event: The event to query
618 * @update: (out): A pointer to the update flag of the segment
619 * @rate: (out): A pointer to the rate of the segment
620 * @applied_rate: (out): A pointer to the applied_rate of the segment
621 * @format: (out): A pointer to the format of the newsegment values
622 * @start: (out): A pointer to store the start value in
623 * @stop: (out): A pointer to store the stop value in
624 * @time: (out): A pointer to store the time value in
626 * Get the update, rate, applied_rate, format, start, stop and
627 * time in the newsegment event. See gst_event_new_new_segment_full()
628 * for a full description of the newsegment event.
633 gst_event_parse_new_segment_full (GstEvent * event, gboolean * update,
634 gdouble * rate, gdouble * applied_rate, GstFormat * format,
635 gint64 * start, gint64 * stop, gint64 * time)
637 const GstStructure *structure;
639 g_return_if_fail (GST_IS_EVENT (event));
640 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
642 structure = event->structure;
643 if (G_LIKELY (update))
645 g_value_get_boolean (gst_structure_id_get_value (structure,
646 GST_QUARK (UPDATE)));
649 g_value_get_double (gst_structure_id_get_value (structure,
651 if (G_LIKELY (applied_rate))
653 g_value_get_double (gst_structure_id_get_value (structure,
654 GST_QUARK (APPLIED_RATE)));
655 if (G_LIKELY (format))
657 g_value_get_enum (gst_structure_id_get_value (structure,
658 GST_QUARK (FORMAT)));
659 if (G_LIKELY (start))
661 g_value_get_int64 (gst_structure_id_get_value (structure,
665 g_value_get_int64 (gst_structure_id_get_value (structure,
669 g_value_get_int64 (gst_structure_id_get_value (structure,
675 * @taglist: (transfer full): metadata list. The event will take ownership
678 * Generates a metadata tag event from the given @taglist.
680 * Returns: (transfer full): a new #GstEvent
683 gst_event_new_tag (GstTagList * taglist)
685 g_return_val_if_fail (taglist != NULL, NULL);
687 return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
691 * gst_event_parse_tag:
692 * @event: a tag event
693 * @taglist: (out) (transfer none): pointer to metadata list
695 * Parses a tag @event and stores the results in the given @taglist location.
696 * No reference to the taglist will be returned, it remains valid only until
697 * the @event is freed. Don't modify or free the taglist, make a copy if you
698 * want to modify it or store it for later use.
701 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
703 g_return_if_fail (GST_IS_EVENT (event));
704 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
707 *taglist = (GstTagList *) event->structure;
710 /* buffersize event */
712 * gst_event_new_buffer_size:
713 * @format: buffer format
714 * @minsize: minimum buffer size
715 * @maxsize: maximum buffer size
716 * @async: thread behavior
718 * Create a new buffersize event. The event is sent downstream and notifies
719 * elements that they should provide a buffer of the specified dimensions.
721 * When the @async flag is set, a thread boundary is prefered.
723 * Returns: (transfer full): a new #GstEvent
726 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
727 gint64 maxsize, gboolean async)
730 GstStructure *structure;
732 GST_CAT_INFO (GST_CAT_EVENT,
733 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
734 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
735 minsize, maxsize, async);
737 structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
738 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
739 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
740 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
741 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
742 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
748 * gst_event_parse_buffer_size:
749 * @event: The event to query
750 * @format: (out): A pointer to store the format in
751 * @minsize: (out): A pointer to store the minsize in
752 * @maxsize: (out): A pointer to store the maxsize in
753 * @async: (out): A pointer to store the async-flag in
755 * Get the format, minsize, maxsize and async-flag in the buffersize event.
758 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
759 gint64 * minsize, gint64 * maxsize, gboolean * async)
761 const GstStructure *structure;
763 g_return_if_fail (GST_IS_EVENT (event));
764 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
766 structure = event->structure;
769 g_value_get_enum (gst_structure_id_get_value (structure,
770 GST_QUARK (FORMAT)));
773 g_value_get_int64 (gst_structure_id_get_value (structure,
774 GST_QUARK (MINSIZE)));
777 g_value_get_int64 (gst_structure_id_get_value (structure,
778 GST_QUARK (MAXSIZE)));
781 g_value_get_boolean (gst_structure_id_get_value (structure,
787 * @proportion: the proportion of the qos message
788 * @diff: The time difference of the last Clock sync
789 * @timestamp: The timestamp of the buffer
791 * Allocate a new qos event with the given values. This function calls
792 * gst_event_new_qos_full() with the type set to #GST_QOS_TYPE_OVERFLOW
793 * when diff is negative (buffers are in time) and #GST_QOS_TYPE_UNDERFLOW
794 * when @diff is positive (buffers are late).
796 * Returns: (transfer full): a new QOS event.
799 gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
800 GstClockTime timestamp)
805 type = GST_QOS_TYPE_OVERFLOW;
807 type = GST_QOS_TYPE_UNDERFLOW;
809 return gst_event_new_qos_full (type, proportion, diff, timestamp);
813 * gst_event_new_qos_full:
814 * @type: the QoS type
815 * @proportion: the proportion of the qos message
816 * @diff: The time difference of the last Clock sync
817 * @timestamp: The timestamp of the buffer
819 * Allocate a new qos event with the given values.
820 * The QOS event is generated in an element that wants an upstream
821 * element to either reduce or increase its rate because of
822 * high/low CPU load or other resource usage such as network performance or
823 * throttling. Typically sinks generate these events for each buffer
826 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
827 * used when a buffer arrived in time or when the sink cannot keep up with
828 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
829 * receiving buffers fast enough and thus has to drop late buffers.
830 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
831 * by the application, for example to reduce power consumption.
833 * @proportion indicates the real-time performance of the streaming in the
834 * element that generated the QoS event (usually the sink). The value is
835 * generally computed based on more long term statistics about the streams
836 * timestamps compared to the clock.
837 * A value < 1.0 indicates that the upstream element is producing data faster
838 * than real-time. A value > 1.0 indicates that the upstream element is not
839 * producing data fast enough. 1.0 is the ideal @proportion value. The
840 * proportion value can safely be used to lower or increase the quality of
843 * @diff is the difference against the clock in running time of the last
844 * buffer that caused the element to generate the QOS event. A negative value
845 * means that the buffer with @timestamp arrived in time. A positive value
846 * indicates how late the buffer with @timestamp was. When throttling is
847 * enabled, @diff will be set to the requested throttling interval.
849 * @timestamp is the timestamp of the last buffer that cause the element
850 * to generate the QOS event. It is expressed in running time and thus an ever
853 * The upstream element can use the @diff and @timestamp values to decide
854 * whether to process more buffers. For possitive @diff, all buffers with
855 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
856 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
857 * result smaller than 0 is not allowed.
859 * The application can use general event probes to intercept the QoS
860 * event and implement custom application specific QoS handling.
862 * Returns: (transfer full): a new QOS event.
867 gst_event_new_qos_full (GstQOSType type, gdouble proportion,
868 GstClockTimeDiff diff, GstClockTime timestamp)
871 GstStructure *structure;
873 /* diff must be positive or timestamp + diff must be positive */
874 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
876 GST_CAT_INFO (GST_CAT_EVENT,
877 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
878 ", timestamp %" GST_TIME_FORMAT, type, proportion,
879 diff, GST_TIME_ARGS (timestamp));
881 structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
882 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
883 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
884 GST_QUARK (DIFF), G_TYPE_INT64, diff,
885 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
886 event = gst_event_new_custom (GST_EVENT_QOS, structure);
892 * gst_event_parse_qos:
893 * @event: The event to query
894 * @proportion: (out): A pointer to store the proportion in
895 * @diff: (out): A pointer to store the diff in
896 * @timestamp: (out): A pointer to store the timestamp in
898 * Get the proportion, diff and timestamp in the qos event. See
899 * gst_event_new_qos() for more information about the different QoS values.
902 gst_event_parse_qos (GstEvent * event, gdouble * proportion,
903 GstClockTimeDiff * diff, GstClockTime * timestamp)
905 gst_event_parse_qos_full (event, NULL, proportion, diff, timestamp);
909 * gst_event_parse_qos_full:
910 * @event: The event to query
911 * @type: (out): A pointer to store the QoS type in
912 * @proportion: (out): A pointer to store the proportion in
913 * @diff: (out): A pointer to store the diff in
914 * @timestamp: (out): A pointer to store the timestamp in
916 * Get the type, proportion, diff and timestamp in the qos event. See
917 * gst_event_new_qos_full() for more information about the different QoS values.
922 gst_event_parse_qos_full (GstEvent * event, GstQOSType * type,
923 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
925 const GstStructure *structure;
927 g_return_if_fail (GST_IS_EVENT (event));
928 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
930 structure = event->structure;
933 g_value_get_enum (gst_structure_id_get_value (structure,
937 g_value_get_double (gst_structure_id_get_value (structure,
938 GST_QUARK (PROPORTION)));
941 g_value_get_int64 (gst_structure_id_get_value (structure,
945 g_value_get_uint64 (gst_structure_id_get_value (structure,
946 GST_QUARK (TIMESTAMP)));
950 * gst_event_new_seek:
951 * @rate: The new playback rate
952 * @format: The format of the seek values
953 * @flags: The optional seek flags
954 * @start_type: The type and flags for the new start position
955 * @start: The value of the new start position
956 * @stop_type: The type and flags for the new stop position
957 * @stop: The value of the new stop position
959 * Allocate a new seek event with the given parameters.
961 * The seek event configures playback of the pipeline between @start to @stop
962 * at the speed given in @rate, also called a playback segment.
963 * The @start and @stop values are expressed in @format.
965 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
966 * Negatives values means backwards playback. A value of 0.0 for the
967 * rate is not allowed and should be accomplished instead by PAUSING the
970 * A pipeline has a default playback segment configured with a start
971 * position of 0, a stop position of -1 and a rate of 1.0. The currently
972 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
974 * @start_type and @stop_type specify how to adjust the currently configured
975 * start and stop fields in playback segment. Adjustments can be made relative
976 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
977 * means that the position should not be updated.
979 * When the rate is positive and @start has been updated, playback will start
980 * from the newly configured start position.
982 * For negative rates, playback will start from the newly configured stop
983 * position (if any). If the stop position if updated, it must be different from
984 * -1 for negative rates.
986 * It is not possible to seek relative to the current playback position, to do
987 * this, PAUSE the pipeline, query the current playback position with
988 * #GST_QUERY_POSITION and update the playback segment current position with a
989 * #GST_SEEK_TYPE_SET to the desired position.
991 * Returns: (transfer full): a new seek event.
994 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
995 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
998 GstStructure *structure;
1000 g_return_val_if_fail (rate != 0.0, NULL);
1002 if (format == GST_FORMAT_TIME) {
1003 GST_CAT_INFO (GST_CAT_EVENT,
1004 "creating seek rate %lf, format TIME, flags %d, "
1005 "start_type %d, start %" GST_TIME_FORMAT ", "
1006 "stop_type %d, stop %" GST_TIME_FORMAT,
1007 rate, flags, start_type, GST_TIME_ARGS (start),
1008 stop_type, GST_TIME_ARGS (stop));
1010 GST_CAT_INFO (GST_CAT_EVENT,
1011 "creating seek rate %lf, format %s, flags %d, "
1012 "start_type %d, start %" G_GINT64_FORMAT ", "
1013 "stop_type %d, stop %" G_GINT64_FORMAT,
1014 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1018 structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
1019 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1020 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1021 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1022 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1023 GST_QUARK (CUR), G_TYPE_INT64, start,
1024 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1025 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1026 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1032 * gst_event_parse_seek:
1033 * @event: a seek event
1034 * @rate: (out): result location for the rate
1035 * @format: (out): result location for the stream format
1036 * @flags: (out): result location for the #GstSeekFlags
1037 * @start_type: (out): result location for the #GstSeekType of the start position
1038 * @start: (out): result location for the start postion expressed in @format
1039 * @stop_type: (out): result location for the #GstSeekType of the stop position
1040 * @stop: (out): result location for the stop postion expressed in @format
1042 * Parses a seek @event and stores the results in the given result locations.
1045 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1046 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1047 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1049 const GstStructure *structure;
1051 g_return_if_fail (GST_IS_EVENT (event));
1052 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1054 structure = event->structure;
1057 g_value_get_double (gst_structure_id_get_value (structure,
1061 g_value_get_enum (gst_structure_id_get_value (structure,
1062 GST_QUARK (FORMAT)));
1065 g_value_get_flags (gst_structure_id_get_value (structure,
1066 GST_QUARK (FLAGS)));
1069 g_value_get_enum (gst_structure_id_get_value (structure,
1070 GST_QUARK (CUR_TYPE)));
1073 g_value_get_int64 (gst_structure_id_get_value (structure,
1077 g_value_get_enum (gst_structure_id_get_value (structure,
1078 GST_QUARK (STOP_TYPE)));
1081 g_value_get_int64 (gst_structure_id_get_value (structure,
1086 * gst_event_new_navigation:
1087 * @structure: (transfer full): description of the event. The event will take
1088 * ownership of the structure.
1090 * Create a new navigation event from the given description.
1092 * Returns: (transfer full): a new #GstEvent
1095 gst_event_new_navigation (GstStructure * structure)
1097 g_return_val_if_fail (structure != NULL, NULL);
1099 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1103 * gst_event_new_latency:
1104 * @latency: the new latency value
1106 * Create a new latency event. The event is sent upstream from the sinks and
1107 * notifies elements that they should add an additional @latency to the
1108 * running time before synchronising against the clock.
1110 * The latency is mostly used in live sinks and is always expressed in
1113 * Returns: (transfer full): a new #GstEvent
1118 gst_event_new_latency (GstClockTime latency)
1121 GstStructure *structure;
1123 GST_CAT_INFO (GST_CAT_EVENT,
1124 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1126 structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
1127 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1128 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1134 * gst_event_parse_latency:
1135 * @event: The event to query
1136 * @latency: (out): A pointer to store the latency in.
1138 * Get the latency in the latency event.
1143 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1145 g_return_if_fail (GST_IS_EVENT (event));
1146 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1150 g_value_get_uint64 (gst_structure_id_get_value (event->structure,
1151 GST_QUARK (LATENCY)));
1155 * gst_event_new_step:
1156 * @format: the format of @amount
1157 * @amount: the amount of data to step
1158 * @rate: the step rate
1159 * @flush: flushing steps
1160 * @intermediate: intermediate steps
1162 * Create a new step event. The purpose of the step event is to instruct a sink
1163 * to skip @amount (expressed in @format) of media. It can be used to implement
1164 * stepping through the video frame by frame or for doing fast trick modes.
1166 * A rate of <= 0.0 is not allowed, pause the pipeline or reverse the playback
1167 * direction of the pipeline to get the same effect.
1169 * The @flush flag will clear any pending data in the pipeline before starting
1170 * the step operation.
1172 * The @intermediate flag instructs the pipeline that this step operation is
1173 * part of a larger step operation.
1175 * Returns: (transfer full): a new #GstEvent
1180 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1181 gboolean flush, gboolean intermediate)
1184 GstStructure *structure;
1186 g_return_val_if_fail (rate > 0.0, NULL);
1188 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1190 structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
1191 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1192 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1193 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1194 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1195 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1196 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1202 * gst_event_parse_step:
1203 * @event: The event to query
1204 * @format: (out) (allow-none): a pointer to store the format in
1205 * @amount: (out) (allow-none): a pointer to store the amount in
1206 * @rate: (out) (allow-none): a pointer to store the rate in
1207 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1208 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1211 * Parse the step event.
1216 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1217 gdouble * rate, gboolean * flush, gboolean * intermediate)
1219 const GstStructure *structure;
1221 g_return_if_fail (GST_IS_EVENT (event));
1222 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1224 structure = event->structure;
1226 *format = g_value_get_enum (gst_structure_id_get_value (structure,
1227 GST_QUARK (FORMAT)));
1229 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1230 GST_QUARK (AMOUNT)));
1232 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1235 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1236 GST_QUARK (FLUSH)));
1238 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1239 GST_QUARK (INTERMEDIATE)));
1243 * gst_event_new_sink_message:
1244 * @msg: (transfer none): the #GstMessage to be posted
1246 * Create a new sink-message event. The purpose of the sink-message event is
1247 * to instruct a sink to post the message contained in the event synchronized
1250 * Returns: (transfer full): a new #GstEvent
1254 /* FIXME 0.11: take ownership of msg for consistency? */
1256 gst_event_new_sink_message (GstMessage * msg)
1259 GstStructure *structure;
1261 g_return_val_if_fail (msg != NULL, NULL);
1263 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1265 structure = gst_structure_id_new (GST_QUARK (EVENT_SINK_MESSAGE),
1266 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1267 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1273 * gst_event_parse_sink_message:
1274 * @event: The event to query
1275 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1277 * Parse the sink-message event. Unref @msg after usage.
1282 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1284 const GstStructure *structure;
1286 g_return_if_fail (GST_IS_EVENT (event));
1287 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1289 structure = event->structure;
1292 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1293 (structure, GST_QUARK (MESSAGE))));