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gstreamer/gst/gstevent.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wim.taymans@chello.be>
* 2005 Wim Taymans <wim@fluendo.com>
*
* 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 class provides factory methods to construct and functions query
* (parse) events.
*
* Events are usually created with gst_event_new_*() which takes event-type
* specific parameters as arguments.
* To send an event application will usually use gst_element_send_event() and
* elements will use gst_pad_send_event() or gst_pad_push_event().
* The event should be unreffed with gst_event_unref() if it has not been sent.
*
* Events that have been received can be parsed with their respective
* gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
*
* Events are passed between elements in parallel to the data stream. Some events
* are serialized with buffers, others are not. Some events only travel downstream,
* others only upstream. Some events can travel both upstream and downstream.
*
* The events are used to signal special conditions in the datastream such as
* EOS (end of stream) or the start of a new stream-segment.
* Events are also used to flush the pipeline of any pending data.
*
* Most of the event API is used inside plugins. Applications usually only
* construct and use seek events.
* To do that gst_event_new_seek() is used to create a seek event. It takes
* the needed parameters to specity seeking time and mode.
* <example>
* <title>performing a seek on a pipeline</title>
* <programlisting>
* GstEvent *event;
* gboolean result;
* ...
* // construct a seek event to play the media from second 2 to 5, flush
* // the pipeline to decrease latency.
* event = gst_event_new_seek (1.0,
* GST_FORMAT_TIME,
* GST_SEEK_FLAG_FLUSH,
* GST_SEEK_TYPE_SET, 2 * GST_SECOND,
* GST_SEEK_TYPE_SET, 5 * GST_SECOND);
* ...
* result = gst_element_send_event (pipeline, event);
* if (!result)
* g_warning ("seek failed");
* ...
* </programlisting>
* </example>
*
* Last reviewed on 2006-09-6 (0.10.10)
*/
#include "gst_private.h"
#include <string.h> /* memcpy */
#include "gstinfo.h"
#include "gstevent.h"
#include "gstenumtypes.h"
#include "gstutils.h"
#include "gstquark.h"
#define GST_EVENT_SEQNUM(e) ((GstEvent*)e)->abidata.seqnum
static void gst_event_finalize (GstEvent * event);
static GstEvent *_gst_event_copy (GstEvent * event);
static GstMiniObjectClass *parent_class = NULL;
void
_gst_event_initialize (void)
{
g_type_class_ref (gst_event_get_type ());
g_type_class_ref (gst_seek_flags_get_type ());
g_type_class_ref (gst_seek_type_get_type ());
}
typedef struct
{
const gint type;
const gchar *name;
GQuark quark;
} GstEventQuarks;
static GstEventQuarks event_quarks[] = {
{GST_EVENT_UNKNOWN, "unknown", 0},
{GST_EVENT_FLUSH_START, "flush-start", 0},
{GST_EVENT_FLUSH_STOP, "flush-stop", 0},
{GST_EVENT_EOS, "eos", 0},
{GST_EVENT_NEWSEGMENT, "newsegment", 0},
{GST_EVENT_TAG, "tag", 0},
{GST_EVENT_BUFFERSIZE, "buffersize", 0},
{GST_EVENT_QOS, "qos", 0},
{GST_EVENT_SEEK, "seek", 0},
{GST_EVENT_NAVIGATION, "navigation", 0},
{GST_EVENT_LATENCY, "latency", 0},
{GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
{GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
{GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
{GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
{GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
{0, NULL, 0}
};
/**
* gst_event_type_get_name:
* @type: the event type
*
* Get a printable name for the given event type. Do not modify or free.
*
* Returns: a reference to the static name of the event.
*/
const gchar *
gst_event_type_get_name (GstEventType type)
{
gint i;
for (i = 0; event_quarks[i].name; i++) {
if (type == event_quarks[i].type)
return event_quarks[i].name;
}
return "unknown";
}
/**
* gst_event_type_to_quark:
* @type: the event type
*
* Get the unique quark for the given event type.
*
* Returns: the quark associated with the event type
*/
GQuark
gst_event_type_to_quark (GstEventType type)
{
gint i;
for (i = 0; event_quarks[i].name; i++) {
if (type == event_quarks[i].type)
return event_quarks[i].quark;
}
return 0;
}
/**
* gst_event_type_get_flags:
* @type: a #GstEventType
*
* Gets the #GstEventTypeFlags associated with @type.
*
* Returns: a #GstEventTypeFlags.
*/
GstEventTypeFlags
gst_event_type_get_flags (GstEventType type)
{
GstEventTypeFlags ret;
ret = type & ((1 << GST_EVENT_TYPE_SHIFT) - 1);
return ret;
}
#define _do_init \
{ \
gint i; \
\
for (i = 0; event_quarks[i].name; i++) { \
event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name); \
} \
}
G_DEFINE_TYPE_WITH_CODE (GstEvent, gst_event, GST_TYPE_MINI_OBJECT, _do_init);
static void
gst_event_class_init (GstEventClass * klass)
{
parent_class = g_type_class_peek_parent (klass);
klass->mini_object_class.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
klass->mini_object_class.finalize =
(GstMiniObjectFinalizeFunction) gst_event_finalize;
}
static void
gst_event_init (GstEvent * event)
{
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_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
GST_EVENT_TYPE_NAME (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);
}
/* GST_MINI_OBJECT_CLASS (parent_class)->finalize (GST_MINI_OBJECT (event)); */
}
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);
GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (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,
&copy->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_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
gst_event_type_get_name (type), type);
event->type = type;
event->src = NULL;
event->structure = NULL;
GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
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;
/* structure must not have a parent */
if (structure)
g_return_val_if_fail (structure->parent_refcount == NULL, NULL);
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_has_name:
* @event: The #GstEvent.
* @name: name to check
*
* Checks if @event has the given @name. This function is usually used to
* check the name of a custom event.
*
* Returns: %TRUE if @name matches the name of the event structure.
*
* Since: 0.10.20
*/
gboolean
gst_event_has_name (GstEvent * event, const gchar * name)
{
g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
if (event->structure == NULL)
return FALSE;
return gst_structure_has_name (event->structure, name);
}
/**
* gst_event_get_seqnum:
* @event: A #GstEvent.
*
* Retrieve the sequence number of a event.
*
* Events have ever-incrementing sequence numbers, which may also be set
* explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
* indicate that a event corresponds to some other set of events or messages,
* for example an EOS event corresponding to a SEEK event. It is considered good
* practice to make this correspondence when possible, though it is not
* required.
*
* Note that events and messages share the same sequence number incrementor;
* two events or messages will never not have the same sequence number unless
* that correspondence was made explicitly.
*
* Returns: The event's sequence number.
*
* MT safe.
*
* Since: 0.10.22
*/
guint32
gst_event_get_seqnum (GstEvent * event)
{
g_return_val_if_fail (GST_IS_EVENT (event), -1);
return GST_EVENT_SEQNUM (event);
}
/**
* gst_event_set_seqnum:
* @event: A #GstEvent.
* @seqnum: A sequence number.
*
* Set the sequence number of a event.
*
* This function might be called by the creator of a event to indicate that the
* event relates to other events or messages. See gst_event_get_seqnum() for
* more information.
*
* MT safe.
*
* Since: 0.10.22
*/
void
gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
{
g_return_if_fail (GST_IS_EVENT (event));
GST_EVENT_SEQNUM (event) = seqnum;
}
/* FIXME 0.11: It would be nice to have flush events
* that don't reset the running time in the sinks
*/
/**
* gst_event_new_flush_start:
*
* Allocate a new flush start event. The flush start event can be sent
* upstream and downstream and travels out-of-bounds with the dataflow.
*
* It marks pads as being flushing and will make them return
* #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
* gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
* gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
* on a flushing pad will return %FALSE immediately.
*
* Elements should unlock any blocking functions and exit their streaming
* functions as fast as possible when this event is received.
*
* This event is typically generated after a seek to flush out all queued data
* in the pipeline so that the new media is played as soon as possible.
*
* 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 stop event can be sent
* upstream and downstream and travels out-of-bounds with the dataflow.
* It is typically sent 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 #GST_FLOW_UNEXPECTED as a #GstFlowReturn
* when data after the EOS event arrives.
*
* The EOS event will travel down to the sink elements in the pipeline
* which will then post the #GST_MESSAGE_EOS on the bus after they have
* finished playing any buffered data.
*
* When all sinks have posted an EOS message, an 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_new_segment:
* @update: is this segment an update to a previous one
* @rate: a new rate for playback
* @format: The format of the segment values
* @start: the start value of the segment
* @stop: the stop value of the segment
* @position: stream position
*
* Allocate a new newsegment event with the given format/values tripplets
*
* This method calls gst_event_new_new_segment_full() passing a default
* value of 1.0 for applied_rate
*
* Returns: A new newsegment event.
*/
GstEvent *
gst_event_new_new_segment (gboolean update, gdouble rate, GstFormat format,
gint64 start, gint64 stop, gint64 position)
{
return gst_event_new_new_segment_full (update, rate, 1.0, format, start,
stop, position);
}
/**
* gst_event_parse_new_segment:
* @event: The event to query
* @update: A pointer to the update flag of the segment
* @rate: A pointer to the rate of the segment
* @format: A pointer to the format of the newsegment values
* @start: A pointer to store the start value in
* @stop: A pointer to store the stop value in
* @position: A pointer to store the stream time in
*
* Get the update flag, rate, format, start, stop and position in the
* newsegment event. In general, gst_event_parse_new_segment_full() should
* be used instead of this, to also retrieve the applied_rate value of the
* segment. See gst_event_new_new_segment_full() for a full description
* of the newsegment event.
*/
void
gst_event_parse_new_segment (GstEvent * event, gboolean * update,
gdouble * rate, GstFormat * format, gint64 * start,
gint64 * stop, gint64 * position)
{
gst_event_parse_new_segment_full (event, update, rate, NULL, format, start,
stop, position);
}
/**
* gst_event_new_new_segment_full:
* @update: Whether this segment is an update to a previous one
* @rate: A new rate for playback
* @applied_rate: The rate factor which has already been applied
* @format: The format of the segment values
* @start: The start value of the segment
* @stop: The stop value of the segment
* @position: stream position
*
* Allocate a new newsegment event with the given format/values triplets.
*
* The newsegment event marks the range of buffers to be processed. All
* data not within the segment range is not to be processed. This can be
* used intelligently by plugins to apply more efficient methods of skipping
* unneeded data. The valid range is expressed with the @start and @stop
* values.
*
* The position value of the segment is used in conjunction with the start
* value to convert the buffer timestamps into the stream time. This is
* usually done in sinks to report the current stream_time.
* @position represents the stream_time of a buffer carrying a timestamp of
* @start. @position cannot be -1.
*
* @start cannot be -1, @stop can be -1. If there
* is a valid @stop given, it must be greater or equal the @start, including
* when the indicated playback @rate is < 0.
*
* The @applied_rate value provides information about any rate adjustment that
* has already been made to the timestamps and content on the buffers of the
* stream. (@rate * @applied_rate) should always equal the rate that has been
* requested for playback. For example, if an element has an input segment
* with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
* incoming timestamps and buffer content by half and output a newsegment event
* with @rate of 1.0 and @applied_rate of 2.0
*
* After a newsegment event, the buffer stream time is calculated with:
*
* position + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
*
* Returns: A new newsegment event.
*
* Since: 0.10.6
*/
GstEvent *
gst_event_new_new_segment_full (gboolean update, gdouble rate,
gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
gint64 position)
{
GstEvent *event;
GstStructure *structure;
g_return_val_if_fail (rate != 0.0, NULL);
g_return_val_if_fail (applied_rate != 0.0, NULL);
if (format == GST_FORMAT_TIME) {
GST_CAT_INFO (GST_CAT_EVENT,
"creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
"start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
", position %" GST_TIME_FORMAT,
update, rate, GST_TIME_ARGS (start),
GST_TIME_ARGS (stop), GST_TIME_ARGS (position));
} else {
GST_CAT_INFO (GST_CAT_EVENT,
"creating newsegment update %d, rate %lf, format %s, "
"start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", position %"
G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
stop, position);
}
g_return_val_if_fail (position != -1, NULL);
g_return_val_if_fail (start != -1, NULL);
if (stop != -1)
g_return_val_if_fail (start <= stop, NULL);
structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
GST_QUARK (START), G_TYPE_INT64, start,
GST_QUARK (STOP), G_TYPE_INT64, stop,
GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);
return event;
}
/**
* gst_event_parse_new_segment_full:
* @event: The event to query
* @update: A pointer to the update flag of the segment
* @rate: A pointer to the rate of the segment
* @applied_rate: A pointer to the applied_rate of the segment
* @format: A pointer to the format of the newsegment values
* @start: A pointer to store the start value in
* @stop: A pointer to store the stop value in
* @position: A pointer to store the stream time in
*
* Get the update, rate, applied_rate, format, start, stop and
* position in the newsegment event. See gst_event_new_new_segment_full()
* for a full description of the newsegment event.
*
* Since: 0.10.6
*/
void
gst_event_parse_new_segment_full (GstEvent * event, gboolean * update,
gdouble * rate, gdouble * applied_rate, GstFormat * format,
gint64 * start, gint64 * stop, gint64 * position)
{
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 (G_LIKELY (update))
*update =
g_value_get_boolean (gst_structure_id_get_value (structure,
GST_QUARK (UPDATE)));
if (G_LIKELY (rate))
*rate =
g_value_get_double (gst_structure_id_get_value (structure,
GST_QUARK (RATE)));
if (G_LIKELY (applied_rate))
*applied_rate =
g_value_get_double (gst_structure_id_get_value (structure,
GST_QUARK (APPLIED_RATE)));
if (G_LIKELY (format))
*format =
g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (FORMAT)));
if (G_LIKELY (start))
*start =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (START)));
if (G_LIKELY (stop))
*stop =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (STOP)));
if (G_LIKELY (position))
*position =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (POSITION)));
}
/**
* gst_event_new_tag:
* @taglist: metadata list. The event will take ownership of @taglist.
*
* 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;
}
/* buffersize event */
/**
* gst_event_new_buffer_size:
* @format: buffer format
* @minsize: minimum buffer size
* @maxsize: maximum buffer size
* @async: thread behavior
*
* Create a new buffersize event. The event is sent downstream and notifies
* elements that they should provide a buffer of the specified dimensions.
*
* When the @async flag is set, a thread boundary is prefered.
*
* Returns: a new #GstEvent
*/
GstEvent *
gst_event_new_buffer_size (GstFormat format, gint64 minsize,
gint64 maxsize, gboolean async)
{
GstEvent *event;
GstStructure *structure;
GST_CAT_INFO (GST_CAT_EVENT,
"creating buffersize format %s, minsize %" G_GINT64_FORMAT
", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
minsize, maxsize, async);
structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
return event;
}
/**
* gst_event_parse_buffer_size:
* @event: The event to query
* @format: A pointer to store the format in
* @minsize: A pointer to store the minsize in
* @maxsize: A pointer to store the maxsize in
* @async: A pointer to store the async-flag in
*
* Get the format, minsize, maxsize and async-flag in the buffersize event.
*/
void
gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
gint64 * minsize, gint64 * maxsize, gboolean * async)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
structure = gst_event_get_structure (event);
if (format)
*format =
g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (FORMAT)));
if (minsize)
*minsize =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (MINSIZE)));
if (maxsize)
*maxsize =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (MAXSIZE)));
if (async)
*async =
g_value_get_boolean (gst_structure_id_get_value (structure,
GST_QUARK (ASYNC)));
}
/**
* 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 or other resource usage such as network performance.
* Typically sinks generate these events for each buffer they receive.
*
* @proportion indicates the real-time performance of the streaming in the
* element that generated the QoS event (usually the sink). The value is
* generally computed based on more long term statistics about the streams
* timestamps compared to the clock.
* A value < 1.0 indicates that the upstream element is producing data faster
* than real-time. A value > 1.0 indicates that the upstream element is not
* producing data fast enough. 1.0 is the ideal @proportion value. The
* proportion value can safely be used to lower or increase the quality of
* the element.
*
* @diff is the difference against the clock in running time of the last
* buffer that caused the element to generate the QOS event. A negative value
* means that the buffer with @timestamp arrived in time. A positive value
* indicates how late the buffer with @timestamp was.
*
* @timestamp is the timestamp of the last buffer that cause the element
* to generate the QOS event. It is expressed in running time and thus an ever
* increasing value.
*
* The upstream element can use the @diff and @timestamp values to decide
* whether to process more buffers. For possitive @diff, all buffers with
* timestamp <= @timestamp + @diff will certainly arrive late in the sink
* as well. A (negative) @diff value so that @timestamp + @diff would yield a
* result smaller than 0 is not allowed.
*
* The application can use general event probes to intercept the QoS
* event and implement custom application specific QoS handling.
*
* Returns: A new QOS event.
*/
GstEvent *
gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
GstClockTime timestamp)
{
GstEvent *event;
GstStructure *structure;
/* diff must be positive or timestamp + diff must be positive */
g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
GST_CAT_INFO (GST_CAT_EVENT,
"creating qos proportion %lf, diff %" G_GINT64_FORMAT
", timestamp %" GST_TIME_FORMAT, proportion,
diff, GST_TIME_ARGS (timestamp));
structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
GST_QUARK (DIFF), G_TYPE_INT64, diff,
GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
event = gst_event_new_custom (GST_EVENT_QOS, structure);
return event;
}
/**
* 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. See
* gst_event_new_qos() for more information about the different QoS values.
*/
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_id_get_value (structure,
GST_QUARK (PROPORTION)));
if (diff)
*diff =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (DIFF)));
if (timestamp)
*timestamp =
g_value_get_uint64 (gst_structure_id_get_value (structure,
GST_QUARK (TIMESTAMP)));
}
/**
* gst_event_new_seek:
* @rate: The new playback rate
* @format: The format of the seek values
* @flags: The optional seek flags
* @start_type: The type and flags for the new start position
* @start: The value of the new start 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 between @start to @stop
* at the speed given in @rate, also called a playback segment.
* The @start and @stop values are expressed in @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 and should be accomplished instead by PAUSING the
* pipeline.
*
* A pipeline has a default playback segment configured with a start
* position of 0, a stop position of -1 and a rate of 1.0. The currently
* configured playback segment can be queried with #GST_QUERY_SEGMENT.
*
* @start_type and @stop_type specify how to adjust the currently configured
* start and stop fields in playback segment. Adjustments can be made relative
* or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
* means that the position should not be updated.
*
* When the rate is positive and @start has been updated, playback will start
* from the newly configured start position.
*
* For negative rates, playback will start from the newly configured stop
* position (if any). If the stop position if updated, it must be different from
* -1 for negative rates.
*
* It is not possible to seek relative to the current playback position, to do
* this, PAUSE the pipeline, query the current playback position with
* #GST_QUERY_POSITION and update the playback segment current position with a
* #GST_SEEK_TYPE_SET to the desired position.
*
* Returns: A new seek event.
*/
GstEvent *
gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
{
GstEvent *event;
GstStructure *structure;
g_return_val_if_fail (rate != 0.0, NULL);
if (format == GST_FORMAT_TIME) {
GST_CAT_INFO (GST_CAT_EVENT,
"creating seek rate %lf, format TIME, flags %d, "
"start_type %d, start %" GST_TIME_FORMAT ", "
"stop_type %d, stop %" GST_TIME_FORMAT,
rate, flags, start_type, GST_TIME_ARGS (start),
stop_type, GST_TIME_ARGS (stop));
} else {
GST_CAT_INFO (GST_CAT_EVENT,
"creating seek rate %lf, format %s, flags %d, "
"start_type %d, start %" G_GINT64_FORMAT ", "
"stop_type %d, stop %" G_GINT64_FORMAT,
rate, gst_format_get_name (format), flags, start_type, start, stop_type,
stop);
}
structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
GST_QUARK (CUR), G_TYPE_INT64, start,
GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
event = gst_event_new_custom (GST_EVENT_SEEK, structure);
return event;
}
/**
* 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
* @start_type: result location for the #GstSeekType of the start position
* @start: result location for the start 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 * start_type,
gint64 * start, 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_id_get_value (structure,
GST_QUARK (RATE)));
if (format)
*format =
g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (FORMAT)));
if (flags)
*flags =
g_value_get_flags (gst_structure_id_get_value (structure,
GST_QUARK (FLAGS)));
if (start_type)
*start_type =
g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (CUR_TYPE)));
if (start)
*start =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (CUR)));
if (stop_type)
*stop_type =
g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (STOP_TYPE)));
if (stop)
*stop =
g_value_get_int64 (gst_structure_id_get_value (structure,
GST_QUARK (STOP)));
}
/**
* gst_event_new_navigation:
* @structure: description of the event. The event will take ownership of the
* structure.
*
* 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);
}
/**
* gst_event_new_latency:
* @latency: the new latency value
*
* Create a new latency event. The event is sent upstream from the sinks and
* notifies elements that they should add an additional @latency to the
* running time before synchronising against the clock.
*
* The latency is mostly used in live sinks and is always expressed in
* the time format.
*
* Returns: a new #GstEvent
*
* Since: 0.10.12
*/
GstEvent *
gst_event_new_latency (GstClockTime latency)
{
GstEvent *event;
GstStructure *structure;
GST_CAT_INFO (GST_CAT_EVENT,
"creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
structure = gst_structure_id_new (GST_QUARK (EVENT_LATENCY),
GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
return event;
}
/**
* gst_event_parse_latency:
* @event: The event to query
* @latency: A pointer to store the latency in.
*
* Get the latency in the latency event.
*
* Since: 0.10.12
*/
void
gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
structure = gst_event_get_structure (event);
if (latency)
*latency =
g_value_get_uint64 (gst_structure_id_get_value (structure,
GST_QUARK (LATENCY)));
}
/**
* gst_event_new_step:
* @format: the format of @amount
* @amount: the amount of data to step
* @rate: the step rate
* @flush: flushing steps
* @intermediate: intermediate steps
*
* Create a new step event. The purpose of the step event is to instruct a sink
* to skip @amount (expressed in @format) of media. It can be used to implement
* stepping through the video frame by frame or for doing fast trick modes.
*
* A rate of <= 0.0 is not allowed, pause the pipeline or reverse the playback
* direction of the pipeline to get the same effect.
*
* The @flush flag will clear any pending data in the pipeline before starting
* the step operation.
*
* The @intermediate flag instructs the pipeline that this step operation is
* part of a larger step operation.
*
* Returns: a new #GstEvent
*
* Since: 0.10.24
*/
GstEvent *
gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
gboolean flush, gboolean intermediate)
{
GstEvent *event;
GstStructure *structure;
g_return_val_if_fail (rate > 0.0, NULL);
GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
structure = gst_structure_id_new (GST_QUARK (EVENT_STEP),
GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
event = gst_event_new_custom (GST_EVENT_STEP, structure);
return event;
}
/**
* gst_event_parse_step:
* @event: The event to query
* @format: A pointer to store the format in.
* @amount: A pointer to store the amount in.
* @rate: A pointer to store the rate in.
* @flush: A pointer to store the flush boolean in.
* @intermediate: A pointer to store the intermediate boolean in.
*
* Parse the step event.
*
* Since: 0.10.24
*/
void
gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
gdouble * rate, gboolean * flush, gboolean * intermediate)
{
const GstStructure *structure;
g_return_if_fail (GST_IS_EVENT (event));
g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
structure = gst_event_get_structure (event);
if (format)
*format = g_value_get_enum (gst_structure_id_get_value (structure,
GST_QUARK (FORMAT)));
if (amount)
*amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
GST_QUARK (AMOUNT)));
if (rate)
*rate = g_value_get_double (gst_structure_id_get_value (structure,
GST_QUARK (RATE)));
if (flush)
*flush = g_value_get_boolean (gst_structure_id_get_value (structure,
GST_QUARK (FLUSH)));
if (intermediate)
*intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
GST_QUARK (INTERMEDIATE)));
}
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