gstreamer/gst/gstevent.c
Stefan Kost 33e36f56a4 inlined remaining docs, added missing doc comments
Original commit message from CVS:
* docs/gst/tmpl/gstevent.sgml:
* gst/gstevent.c:
* gst/gstevent.h:
inlined remaining docs, added missing doc comments
2005-08-22 10:37:02 +00:00

557 lines
16 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wim.taymans@chello.be>
*
* gstevent.c: GstEvent subsystem
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstevent
* @short_description: Structure describing events that are passed up and down a pipeline
* @see_also: #GstPad, #GstElement
*
* The event classes are used to construct and query events.
*
* Events are usually created with gst_event_new() which takes the event type as
* an argument. Properties specific to the event can be set afterwards with the
* provided macros. The event should be unreferenced with gst_event_unref().
*
* gst_event_new_seek() is a usually used to create a seek event and it takes
* the needed parameters for a seek event.
*
* gst_event_new_flush() creates a new flush event.
*/
#include <string.h> /* memcpy */
#include "gst_private.h"
#include "gstinfo.h"
#include "gstevent.h"
#include "gstenumtypes.h"
#include "gstutils.h"
static void gst_event_init (GTypeInstance * instance, gpointer g_class);
static void gst_event_class_init (gpointer g_class, gpointer class_data);
static void gst_event_finalize (GstEvent * event);
static GstEvent *_gst_event_copy (GstEvent * event);
void
_gst_event_initialize (void)
{
gst_event_get_type ();
}
GType
gst_event_get_type (void)
{
static GType _gst_event_type;
if (G_UNLIKELY (_gst_event_type == 0)) {
static const GTypeInfo event_info = {
sizeof (GstEventClass),
NULL,
NULL,
gst_event_class_init,
NULL,
NULL,
sizeof (GstEvent),
0,
gst_event_init,
NULL
};
_gst_event_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
"GstEvent", &event_info, 0);
}
return _gst_event_type;
}
static void
gst_event_class_init (gpointer g_class, gpointer class_data)
{
GstEventClass *event_class = GST_EVENT_CLASS (g_class);
event_class->mini_object_class.copy =
(GstMiniObjectCopyFunction) _gst_event_copy;
event_class->mini_object_class.finalize =
(GstMiniObjectFinalizeFunction) gst_event_finalize;
}
static void
gst_event_init (GTypeInstance * instance, gpointer g_class)
{
GstEvent *event;
event = GST_EVENT (instance);
GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
}
static void
gst_event_finalize (GstEvent * event)
{
g_return_if_fail (event != NULL);
g_return_if_fail (GST_IS_EVENT (event));
GST_CAT_INFO (GST_CAT_EVENT, "freeing event %p", event);
if (GST_EVENT_SRC (event)) {
gst_object_unref (GST_EVENT_SRC (event));
GST_EVENT_SRC (event) = NULL;
}
if (event->structure) {
gst_structure_set_parent_refcount (event->structure, NULL);
gst_structure_free (event->structure);
}
}
static GstEvent *
_gst_event_copy (GstEvent * event)
{
GstEvent *copy;
copy = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
if (GST_EVENT_SRC (event)) {
GST_EVENT_SRC (copy) = gst_object_ref (GST_EVENT_SRC (event));
}
if (event->structure) {
copy->structure = gst_structure_copy (event->structure);
gst_structure_set_parent_refcount (copy->structure,
&event->mini_object.refcount);
}
return copy;
}
static GstEvent *
gst_event_new (GstEventType type)
{
GstEvent *event;
event = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
GST_CAT_INFO (GST_CAT_EVENT, "creating new event %p %d", event, type);
event->type = type;
event->src = NULL;
event->structure = NULL;
return event;
}
/**
* gst_event_new_custom:
* @type: The type of the new event
* @structure: The structure for the event. The event will take ownership of
* the structure.
*
* Create a new custom-typed event. This can be used for anything not
* handled by other event-specific functions to pass an event to another
* element.
*
* Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
* assigning a free number and filling in the correct direction and
* serialization flags.
*
* New custom events can also be created by subclassing the event type if
* needed.
*
* Returns: The new custom event.
*/
GstEvent *
gst_event_new_custom (GstEventType type, GstStructure * structure)
{
GstEvent *event;
event = gst_event_new (type);
if (structure) {
gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
event->structure = structure;
}
return event;
}
/**
* gst_event_get_structure:
* @event: The #GstEvent.
*
* Access the structure of the event.
*
* Returns: The structure of the event. The structure is still
* owned by the event, which means that you should not free it and
* that the pointer becomes invalid when you free the event.
*
* MT safe.
*/
const GstStructure *
gst_event_get_structure (GstEvent * event)
{
g_return_val_if_fail (GST_IS_EVENT (event), NULL);
return event->structure;
}
/**
* gst_event_new_flush_start:
*
* Allocate a new flush start event. The flush start event can be send
* upstream and downstream and travels out-of-bounds with the dataflow.
* It marks pads as being in a WRONG_STATE to process more data.
*
* Elements unlock and blocking functions and exit their streaming functions
* as fast as possible.
*
* This event is typically generated after a seek to minimize the latency
* after the seek.
*
* Returns: A new flush start event.
*/
GstEvent *
gst_event_new_flush_start (void)
{
return gst_event_new (GST_EVENT_FLUSH_START);
}
/**
* gst_event_new_flush_stop:
*
* Allocate a new flush stop event. The flush start event can be send
* upstream and downstream and travels out-of-bounds with the dataflow.
* It is typically send after sending a FLUSH_START event to make the
* pads accept data again.
*
* Elements can process this event synchronized with the dataflow since
* the preceeding FLUSH_START event stopped the dataflow.
*
* This event is typically generated to complete a seek and to resume
* dataflow.
*
* Returns: A new flush stop event.
*/
GstEvent *
gst_event_new_flush_stop (void)
{
return gst_event_new (GST_EVENT_FLUSH_STOP);
}
/**
* gst_event_new_eos:
*
* Create a new EOS event. The eos event can only travel downstream
* synchronized with the buffer flow. Elements that receive the EOS
* event on a pad can return UNEXPECTED as a GstFlowReturn when data
* after the EOS event arrives.
*
* The EOS event will travel up to the sink elements in the pipeline
* which will then post the GST_MESSAGE_EOS on the bus.
*
* When all sinks have posted an EOS message, the EOS message is
* forwarded to the application.
*
* Returns: The new EOS event.
*/
GstEvent *
gst_event_new_eos (void)
{
return gst_event_new (GST_EVENT_EOS);
}
/**
* gst_event_new_newsegment:
* @rate: a new rate for playback
* @format: The format of the segment values
* @start_val: the start value of the segment
* @stop_val: the stop value of the segment
* @base: base value for buffer timestamps.
*
* Allocate a new newsegment event with the given format/values tripplets.
*
* The newsegment event marks the range of buffers to be processed. All
* data not within the segment range is not to be processed.
*
* The base time of the segment is used to convert the buffer timestamps
* into the stream time again.
*
* After a newsegment event, the buffer stream time is calculated with:
*
* TIMESTAMP(buf) - start_time + base
*
* Returns: A new newsegment event.
*/
GstEvent *
gst_event_new_newsegment (gdouble rate, GstFormat format,
gint64 start_val, gint64 stop_val, gint64 base)
{
return gst_event_new_custom (GST_EVENT_NEWSEGMENT,
gst_structure_new ("GstEventNewsegment", "rate", G_TYPE_DOUBLE, rate,
"format", GST_TYPE_FORMAT, format,
"start_val", G_TYPE_INT64, start_val,
"stop_val", G_TYPE_INT64, stop_val,
"base", G_TYPE_INT64, base, NULL));
}
/**
* gst_event_parse_newsegment:
* @event: The event to query
* @rate: A pointer to the rate of the segment
* @format: A pointer to the format of the newsegment values
* @start_value: A pointer to store the start value in
* @stop_value: A pointer to store the stop value in
* @base: A pointer to store the base time in
*
* Get the start, stop and format in the newsegment event.
*/
void
gst_event_parse_newsegment (GstEvent * event, gdouble * rate,
GstFormat * format, gint64 * start_value, gint64 * stop_value,
gint64 * base)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);
structure = gst_event_get_structure (event);
if (rate)
*rate = g_value_get_double (gst_structure_get_value (structure, "rate"));
if (format)
*format = g_value_get_enum (gst_structure_get_value (structure, "format"));
if (start_value)
*start_value =
g_value_get_int64 (gst_structure_get_value (structure, "start_val"));
if (stop_value)
*stop_value =
g_value_get_int64 (gst_structure_get_value (structure, "stop_val"));
if (base)
*base = g_value_get_int64 (gst_structure_get_value (structure, "base"));
}
/* tag event */
/**
* gst_event_new_tag:
* @taglist: metadata list
*
* Generates a metadata tag event from the given @taglist.
*
* Returns: a new #GstEvent
*/
GstEvent *
gst_event_new_tag (GstTagList * taglist)
{
g_return_val_if_fail (taglist != NULL, NULL);
return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
}
/**
* gst_event_parse_tag:
* @event: a tag event
* @taglist: pointer to metadata list
*
* Parses a tag @event and stores the results in the given @taglist location.
*/
void
gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
{
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
if (taglist)
*taglist = (GstTagList *) event->structure;
}
/* filler event */
/**
* gst_event_new_filler:
*
* Create a new dummy event that should be ignored.
*
* Returns: a new #GstEvent
*/
GstEvent *
gst_event_new_filler (void)
{
return gst_event_new (GST_EVENT_FILLER);
}
/**
* gst_event_new_qos:
* @proportion: the proportion of the qos message
* @diff: The time difference of the last Clock sync
* @timestamp: The timestamp of the buffer
*
* Allocate a new qos event with the given values.
* The QOS event is generated in an element that wants an upstream
* element to either reduce or increase its rate because of
* high/low CPU load.
*
* proportion is the requested adjustment in datarate, 1.0 is the normal
* datarate, 0.75 means increase datarate by 75%, 1.5 is 150%. Negative
* values request a slow down, so -0.75 means a decrease by 75%.
*
* diff is the difference against the clock in stream time of the last
* buffer that caused the element to generate the QOS event.
*
* timestamp is the timestamp of the last buffer that cause the element
* to generate the QOS event.
*
* Returns: A new QOS event.
*/
GstEvent *
gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
GstClockTime timestamp)
{
return gst_event_new_custom (GST_EVENT_QOS,
gst_structure_new ("GstEventQOS",
"proportion", G_TYPE_DOUBLE, proportion,
"diff", G_TYPE_INT64, diff,
"timestamp", G_TYPE_UINT64, timestamp, NULL));
}
/**
* gst_event_parse_qos:
* @event: The event to query
* @proportion: A pointer to store the proportion in
* @diff: A pointer to store the diff in
* @timestamp: A pointer to store the timestamp in
*
* Get the proportion, diff and timestamp in the qos event.
*/
void
gst_event_parse_qos (GstEvent * event, gdouble * proportion,
GstClockTimeDiff * diff, GstClockTime * timestamp)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
structure = gst_event_get_structure (event);
if (proportion)
*proportion =
g_value_get_double (gst_structure_get_value (structure, "proportion"));
if (diff)
*diff = g_value_get_int64 (gst_structure_get_value (structure, "diff"));
if (timestamp)
*timestamp =
g_value_get_uint64 (gst_structure_get_value (structure, "timestamp"));
}
/**
* gst_event_new_seek:
* @rate: The new playback rate
* @format: The format of the seek values
* @flags: The optional seek flags.
* @cur_type: The type and flags for the new current position
* @cur: The value of the new current position
* @stop_type: The type and flags for the new stop position
* @stop: The value of the new stop position
*
* Allocate a new seek event with the given parameters.
*
* The seek event configures playback of the pipeline from
* @cur to @stop at the speed given in @rate.
* The @cur and @stop values are expressed in format @format.
*
* A @rate of 1.0 means normal playback rate, 2.0 means double speed.
* Negatives values means backwards playback. A value of 0.0 for the
* rate is not allowed.
*
* @cur_type and @stop_type specify how to adjust the current and stop
* time, relative or absolute. A type of #GST_EVENT_TYPE_NONE means that
* the position should not be updated.
*
* Returns: A new seek event.
*/
GstEvent *
gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
GstSeekType cur_type, gint64 cur, GstSeekType stop_type, gint64 stop)
{
return gst_event_new_custom (GST_EVENT_SEEK,
gst_structure_new ("GstEventSeek", "rate", G_TYPE_DOUBLE, rate,
"format", GST_TYPE_FORMAT, format,
"flags", GST_TYPE_SEEK_FLAGS, flags,
"cur_type", GST_TYPE_SEEK_TYPE, cur_type,
"cur", G_TYPE_INT64, cur,
"stop_type", GST_TYPE_SEEK_TYPE, stop_type,
"stop", G_TYPE_INT64, stop, NULL));
}
/**
* gst_event_parse_seek:
* @event: a seek event
* @rate: result location for the rate
* @format: result location for the stream format
* @flags: result location for the #GstSeekFlags
* @cur_type: result location for the #GstSeekType of the current position
* @cur: result location for the current postion expressed in @format
* @stop_type: result location for the #GstSeekType of the stop position
* @stop: result location for the stop postion expressed in @format
*
* Parses a seek @event and stores the results in the given result locations.
*/
void
gst_event_parse_seek (GstEvent * event, gdouble * rate, GstFormat * format,
GstSeekFlags * flags,
GstSeekType * cur_type, gint64 * cur,
GstSeekType * stop_type, gint64 * stop)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
structure = gst_event_get_structure (event);
if (rate)
*rate = g_value_get_double (gst_structure_get_value (structure, "rate"));
if (format)
*format = g_value_get_enum (gst_structure_get_value (structure, "format"));
if (flags)
*flags = g_value_get_flags (gst_structure_get_value (structure, "flags"));
if (cur_type)
*cur_type =
g_value_get_enum (gst_structure_get_value (structure, "cur_type"));
if (cur)
*cur = g_value_get_int64 (gst_structure_get_value (structure, "cur"));
if (stop_type)
*stop_type =
g_value_get_enum (gst_structure_get_value (structure, "stop_type"));
if (stop)
*stop = g_value_get_int64 (gst_structure_get_value (structure, "stop"));
}
/* navigation event */
/**
* gst_event_new_navigation:
* @structure: description of the event
*
* Create a new navigation event from the given description.
*
* Returns: a new #GstEvent
*/
GstEvent *
gst_event_new_navigation (GstStructure * structure)
{
g_return_val_if_fail (structure != NULL, NULL);
return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
}