flags for this object
The name of the object
the parent structure
this object's parent, weak ref
Attach the #GstControlBinding to the object. If there already was a #GstControlBinding for this property it will be replaced.
The object's reference count will be incremented, and any floating reference will be removed (see gst_object_ref_sink())
the #GstControlBinding that should be used
The time master of the master clock and the time slave of the slave
clock are added to the list of observations. If enough observations
are available, a linear regression algorithm is run on the
observations and clock is recalibrated.
If this functions returns %TRUE, r_squared will contain the
correlation coefficient of the interpolation. A value of 1.0
means a perfect regression was performed. This value can
be used to control the sampling frequency of the master and slave
clocks.
a time on the slave
a time on the master
Add a clock observation to the internal slaving algorithm the same as gst_clock_add_observation(), and return the result of the master clock estimation, without updating the internal calibration.
The caller can then take the results and call gst_clock_set_calibration() with the values, or some modified version of them.
a time on the slave
a time on the master
Converts the given internal clock time to the external time, adjusting for the
rate and reference time set with gst_clock_set_calibration() and making sure
that the returned time is increasing. This function should be called with the
clock's OBJECT_LOCK held and is mainly used by clock subclasses.
This function is the reverse of gst_clock_unadjust_unlocked().
a clock time
Converts the given internal_target clock time to the external time,
using the passed calibration parameters. This function performs the
same calculation as gst_clock_adjust_unlocked() when called using the
current calibration parameters, but doesn't ensure a monotonically
increasing result as gst_clock_adjust_unlocked() does.
Note: The clock parameter is unused and can be NULL
a clock time
a reference internal time
a reference external time
the numerator of the rate of the clock relative to its internal time
the denominator of the rate of the clock
Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets the internal rate and reference time of clock. See
gst_clock_set_calibration() for more information.
internal, external, rate_num, and rate_denom can be left %NULL if the
caller is not interested in the values.
Gets the corresponding #GstControlBinding for the property. This should be unreferenced again after use.
name of the property
Obtain the control-rate for this object. Audio processing #GstElement
objects will use this rate to sub-divide their processing loop and call
gst_object_sync_values() in between. The length of the processing segment
should be up to control-rate nanoseconds.
If the object is not under property control, this will return
%GST_CLOCK_TIME_NONE. This allows the element to avoid the sub-dividing.
The control-rate is not expected to change if the element is in %GST_STATE_PAUSED or %GST_STATE_PLAYING.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Gets a number of #GValues for the given controlled property starting at the
requested time. The array values need to hold enough space for n_values of
#GValue.
This function is useful if one wants to e.g. draw a graph of the control curve or apply a control curve sample by sample.
the name of the property to get
the time that should be processed
the time spacing between subsequent values
array to put control-values in
Gets the current internal time of the given clock. The time is returned unadjusted for the offset and the rate.
Returns a copy of the name of object.
Caller should g_free() the return value after usage.
For a nameless object, this returns %NULL, which you can safely g_free()
as well.
Free-function: g_free
Generates a string describing the path of object in
the object hierarchy. Only useful (or used) for debugging.
Free-function: g_free
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
Gets the accuracy of the clock. The accuracy of the clock is the granularity of the values returned by gst_clock_get_time().
Gets the current time of the given clock. The time is always monotonically increasing and adjusted according to the current offset and rate.
Gets the amount of time that master and slave clocks are sampled.
Gets the value for the given controlled property at the requested time.
the name of the property to get
the time the control-change should be read from
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Check if the object has active controlled properties.
Checks whether object has a [floating][floating-ref] reference.
Checks if the clock is currently synced, by looking at whether %GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC is set.
Gets an ID from clock to trigger a periodic notification.
The periodic notifications will start at time start_time and
will then be fired with the given interval.
the requested start time
the requested interval
Gets a #GstClockID from clock to trigger a single shot
notification at the requested time.
the requested time
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
Reinitializes the provided periodic id to the provided start time and
interval. Does not modify the reference count.
a #GstClockID
the requested start time
the requested interval
Increments the reference count on object. This function
does not take the lock on object because it relies on
atomic refcounting.
This object returns the input parameter to ease writing constructs like : result = gst_object_ref (object->parent);
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
Removes the corresponding #GstControlBinding. If it was the last ref of the binding, it will be disposed.
the binding
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Adjusts the rate and time of clock. A rate of 1/1 is the normal speed of
the clock. Values bigger than 1/1 make the clock go faster.
internal and external are calibration parameters that arrange that
gst_clock_get_time() should have been external at internal time internal.
This internal time should not be in the future; that is, it should be less
than the value of gst_clock_get_internal_time() when this function is called.
Subsequent calls to gst_clock_get_time() will return clock times computed as follows:
time = (internal_time - internal) * rate_num / rate_denom + external
This formula is implemented in gst_clock_adjust_unlocked(). Of course, it tries to do the integer arithmetic as precisely as possible.
Note that gst_clock_get_time() always returns increasing values so when you move the clock backwards, gst_clock_get_time() will report the previous value until the clock catches up.
a reference internal time
a reference external time
the numerator of the rate of the clock relative to its internal time
the denominator of the rate of the clock
This function is used to disable the control bindings on a property for some time, i.e. gst_object_sync_values() will do nothing for the property.
property to disable
boolean that specifies whether to disable the controller or not.
This function is used to disable all controlled properties of the object for
some time, i.e. gst_object_sync_values() will do nothing.
boolean that specifies whether to disable the controller or not.
Change the control-rate for this object. Audio processing #GstElement
objects will use this rate to sub-divide their processing loop and call
gst_object_sync_values() in between. The length of the processing segment
should be up to control-rate nanoseconds.
The control-rate should not change if the element is in %GST_STATE_PAUSED or %GST_STATE_PLAYING.
the new control-rate in nanoseconds.
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Sets master as the master clock for clock. clock will be automatically
calibrated so that gst_clock_get_time() reports the same time as the
master clock.
A clock provider that slaves its clock to a master can get the current calibration values with gst_clock_get_calibration().
master can be %NULL in which case clock will not be slaved anymore. It will
however keep reporting its time adjusted with the last configured rate
and time offsets.
Sets the name of object, or gives object a guaranteed unique
name (if name is %NULL).
This function makes a copy of the provided name, so the caller
retains ownership of the name it sent.
new name of object
Sets a property on an object.
the name of the property to set
the value
Sets the accuracy of the clock. Some clocks have the possibility to operate with different accuracy at the expense of more resource usage. There is normally no need to change the default resolution of a clock. The resolution of a clock can only be changed if the clock has the #GST_CLOCK_FLAG_CAN_SET_RESOLUTION flag set.
The resolution to set
Sets clock to synced and emits the #GstClock::synced signal, and wakes up any
thread waiting in gst_clock_wait_for_sync().
This function must only be called if %GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC is set on the clock, and is intended to be called by subclasses only.
if the clock is synced
Sets the amount of time, in nanoseconds, to sample master and slave clocks
a timeout
Reinitializes the provided single shot id to the provided time. Does not
modify the reference count.
a #GstClockID
The requested time.
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Returns a suggestion for timestamps where buffers should be split to get best controller results.
Sets the properties of the object, according to the #GstControlSources that (maybe) handle them and for the given timestamp.
If this function fails, it is most likely the application developers fault. Most probably the control sources are not setup correctly.
the time that should be processed
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Converts the given external clock time to the internal time of clock,
using the rate and reference time set with gst_clock_set_calibration().
This function should be called with the clock's OBJECT_LOCK held and
is mainly used by clock subclasses.
This function is the reverse of gst_clock_adjust_unlocked().
an external clock time
Converts the given external_target clock time to the internal time,
using the passed calibration parameters. This function performs the
same calculation as gst_clock_unadjust_unlocked() when called using the
current calibration parameters.
Note: The clock parameter is unused and can be NULL
a clock time
a reference internal time
a reference external time
the numerator of the rate of the clock relative to its internal time
the denominator of the rate of the clock
Clear the parent of object, removing the associated reference.
This function decreases the refcount of object.
MT safe. Grabs and releases object's lock.
Decrements the reference count on object. If reference count hits
zero, destroy object. This function does not take the lock
on object as it relies on atomic refcounting.
The unref method should never be called with the LOCK held since this might deadlock the dispose function.
Waits until clock is synced for reporting the current time. If timeout
is %GST_CLOCK_TIME_NONE it will wait forever, otherwise it will time out
after timeout nanoseconds.
For asynchronous waiting, the #GstClock::synced signal can be used.
This returns immediately with %TRUE if %GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC is not set on the clock, or if the clock is already synced.
timeout for waiting or %GST_CLOCK_TIME_NONE
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Checks to see if there is any object named name in list. This function
does not do any locking of any kind. You might want to protect the
provided list with the lock of the owner of the list. This function
will lock each #GstObject in the list to compare the name, so be
careful when passing a list with a locked object.
A default deep_notify signal callback for an object. The user data should contain a pointer to an array of strings that should be excluded from the notify. The default handler will print the new value of the property using g_print.
MT safe. This function grabs and releases object's LOCK for getting its
path string.
the #GObject that signalled the notify.
a #GstObject that initiated the notify.
a #GParamSpec of the property.
a set of user-specified properties to exclude or %NULL to show all changes.
Compares the two #GstClockID instances. This function can be used as a GCompareFunc when sorting ids.
A #GstClockID
A #GstClockID to compare with
Gets the time of the clock ID
The #GstClockID to query
Increases the refcount of given id.
The #GstClockID to ref
Unrefs given id. When the refcount reaches 0 the
#GstClockID will be freed.
The #GstClockID to unref
Cancels an outstanding request with id. This can either
be an outstanding async notification or a pending sync notification.
After this call, id cannot be used anymore to receive sync or
async notifications, you need to create a new #GstClockID.
The id to unschedule
This function returns whether id uses clock as the underlying clock.
clock can be NULL, in which case the return value indicates whether
the underlying clock has been freed. If this is the case, the id is
no longer usable and should be freed.
Performs a blocking wait on id.
id should have been created with gst_clock_new_single_shot_id()
or gst_clock_new_periodic_id() and should not have been unscheduled
with a call to gst_clock_id_unschedule().
If the jitter argument is not %NULL and this function returns #GST_CLOCK_OK
or #GST_CLOCK_EARLY, it will contain the difference
against the clock and the time of id when this method was
called.
Positive values indicate how late id was relative to the clock
(in which case this function will return #GST_CLOCK_EARLY).
Negative values indicate how much time was spent waiting on the clock
before this function returned.
The #GstClockID to wait on
Registers a callback on the given #GstClockID id with the given
function and user_data. When passing a #GstClockID with an invalid
time to this function, the callback will be called immediately
with a time set to %GST_CLOCK_TIME_NONE. The callback will
be called when the time of id has been reached.
The callback func can be invoked from any thread, either provided by the
core or from a streaming thread. The application should be prepared for this.
a #GstClockID to wait on
The callback function
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
Atomically modifies a pointer to point to a new object.
The reference count of oldobj is decreased and the reference count of
newobj is increased.
Either newobj and the value pointed to by oldobj may be %NULL.
pointer to a place of a #GstObject to replace
a new #GstObject
GStreamer uses a global clock to synchronize the plugins in a pipeline. Different clock implementations are possible by implementing this abstract base class or, more conveniently, by subclassing #GstSystemClock.
The #GstClock returns a monotonically increasing time with the method gst_clock_get_time(). Its accuracy and base time depend on the specific clock implementation but time is always expressed in nanoseconds. Since the baseline of the clock is undefined, the clock time returned is not meaningful in itself, what matters are the deltas between two clock times. The time returned by a clock is called the absolute time.
The pipeline uses the clock to calculate the running time. Usually all renderers synchronize to the global clock using the buffer timestamps, the #GST_EVENT_SEGMENT events and the element's base time, see #GstPipeline.
A clock implementation can support periodic and single shot clock notifications both synchronous and asynchronous.
One first needs to create a #GstClockID for the periodic or single shot notification using gst_clock_new_single_shot_id() or gst_clock_new_periodic_id().
To perform a blocking wait for the specific time of the #GstClockID use gst_clock_id_wait(). To receive a callback when the specific time is reached in the clock use gst_clock_id_wait_async(). Both these calls can be interrupted with the gst_clock_id_unschedule() call. If the blocking wait is unscheduled a return value of #GST_CLOCK_UNSCHEDULED is returned.
Periodic callbacks scheduled async will be repeatedly called automatically until they are unscheduled. To schedule a sync periodic callback, gst_clock_id_wait() should be called repeatedly.
The async callbacks can happen from any thread, either provided by the core or from a streaming thread. The application should be prepared for this.
A #GstClockID that has been unscheduled cannot be used again for any wait operation, a new #GstClockID should be created and the old unscheduled one should be destroyed with gst_clock_id_unref().
It is possible to perform a blocking wait on the same #GstClockID from multiple threads. However, registering the same #GstClockID for multiple async notifications is not possible, the callback will only be called for the thread registering the entry last.
None of the wait operations unref the #GstClockID, the owner is responsible for unreffing the ids itself. This holds for both periodic and single shot notifications. The reason being that the owner of the #GstClockID has to keep a handle to the #GstClockID to unblock the wait on FLUSHING events or state changes and if the entry would be unreffed automatically, the handle might become invalid without any notification.
These clock operations do not operate on the running time, so the callbacks will also occur when not in PLAYING state as if the clock just keeps on running. Some clocks however do not progress when the element that provided the clock is not PLAYING.
When a clock has the #GST_CLOCK_FLAG_CAN_SET_MASTER flag set, it can be slaved to another #GstClock with gst_clock_set_master(). The clock will then automatically be synchronized to this master clock by repeatedly sampling the master clock and the slave clock and recalibrating the slave clock with gst_clock_set_calibration(). This feature is mostly useful for plugins that have an internal clock but must operate with another clock selected by the #GstPipeline. They can track the offset and rate difference of their internal clock relative to the master clock by using the gst_clock_get_calibration() function.
The master/slave synchronisation can be tuned with the #GstClock:timeout, #GstClock:window-size and #GstClock:window-threshold properties. The #GstClock:timeout property defines the interval to sample the master clock and run the calibration functions. #GstClock:window-size defines the number of samples to use when calibrating and #GstClock:window-threshold defines the minimum number of samples before the calibration is performed.