Abstract class for global clocks GStreamer uses a global clock to synchronize the plugins in a pipeline. More...

#include <gstreamermm/clock.h>

Inheritance diagram for Gst::Clock:

[legend]

Public Member Functions
	Clock (Clock&& src) noexcept

Clock&	operator= (Clock&& src) noexcept

	~Clock () noexcept override

GstClock*	gobj ()
	Provides access to the underlying C GObject. More...

const GstClock*	gobj () const
	Provides access to the underlying C GObject. More...

GstClock*	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

bool	add_observation (Gst::ClockTime slave_time, Gst::ClockTime master_time, gdouble& result)
	The time master_time of the master clock and the time slave_time of the slave clock are added to the list of observations. More...

bool	add_observation (Gst::ClockTime slave_time, Gst::ClockTime master_time, gdouble& result, Gst::ClockTime&internal, Gst::ClockTime& external, Gst::ClockTime& rate_num, Gst::ClockTime& rate_denom)
	Add a clock observation to the internal slaving algorithm the same as add_observation(), and return the result of the master clock estimation, without updating the internal calibration. More...

bool	set_master (const Clock& master_clock)
	Set master_clock as the master clock for clock. More...

Glib::RefPtr< Gst::Clock >	get_master ()
	Get the master clock that clock is slaved to or `nullptr` when the clock is not slaved to any master clock. More...

Glib::RefPtr< const Gst::Clock >	get_master () const
	Get the master clock that clock is slaved to or `nullptr` when the clock is not slaved to any master clock. More...

Gst::ClockTime	set_resolution (Gst::ClockTime resolution)
	Set the accuracy of the clock. More...

Gst::ClockTime	get_resolution () const
	Get the accuracy of the clock. More...

Gst::ClockTime	get_time () const
	Gets the current time of the given clock. More...

Glib::RefPtr< Gst::ClockID >	create_single_shot_id (Gst::ClockTime time)
	Get a Gst::ClockID from clock to trigger a single shot notification at the requested time. More...

Glib::RefPtr< Gst::ClockID >	create_periodic_id (Gst::ClockTime start_time, Gst::ClockTime intervals)
	Get an ID from clock to trigger a periodic notification. More...

bool	single_shot_id_reinit (const Glib::RefPtr< Gst::ClockID >& id, Gst::ClockTime time)
	Reinitializes the provided single shot id to the provided time. More...

bool	periodic_id_reinit (const Glib::RefPtr< Gst::ClockID >& id, Gst::ClockTime start_time, Gst::ClockTime interval)
	Reinitializes the provided periodic id to the provided start time and interval. More...

Gst::ClockTime	get_internal_time () const
	Gets the current internal time of the given clock. More...

Gst::ClockTime	adjust_unlocked (Gst::ClockTime internal_time)
	Converts the given internal_time clock time to the external time, adjusting for the rate and reference time set with set_calibration() and making sure that the returned time is increasing. More...

Gst::ClockTime	unadjust_unlocked (Gst::ClockTime external_time)
	Converts the given external_time clock time to the internal time of clock, using the rate and reference time set with set_calibration(). More...

Gst::ClockTime	adjust_with_calibration (Gst::ClockTime internal_target, Gst::ClockTime cinternal, Gst::ClockTime cexternal, Gst::ClockTime cnum, Gst::ClockTime cdenom)
	Converts the given internal_target clock time to the external time, using the passed calibration parameters. More...

Gst::ClockTime	unadjust_with_calibration (Gst::ClockTime external_target, Gst::ClockTime cinternal, Gst::ClockTime cexternal, Gst::ClockTime cnum, Gst::ClockTime cdenom)
	Converts the given external_target clock time to the internal time, using the passed calibration parameters. More...

void	get_calibration (Gst::ClockTime&internal, Gst::ClockTime& external, Gst::ClockTime& rate_num, Gst::ClockTime& rate_denom) const
	Gets the internal rate and reference time of clock. More...

void	set_calibration (Gst::ClockTime internal, Gst::ClockTime external, Gst::ClockTime rate_num, Gst::ClockTime rate_denom)
	Adjusts the rate and time of clock. More...

bool	wait_for_sync (Gst::ClockTime timeout)
	Waits until clock is synced for reporting the current time. More...

bool	is_synced () const
	Checks if the clock is currently synced. More...

void	set_synced (bool synced)
	Sets clock to synced and emits the GstClock::synced signal, and wakes up any thread waiting in wait_for_sync(). More...

Glib::PropertyProxy< guint64 >	property_timeout ()
	get/set timeout can be achieved through 'timeout' property, so wrapping gst_clock_{get\|set\|_timeout is unnecessary. More...

Glib::PropertyProxy_ReadOnly< guint64 >	property_timeout () const
	The amount of time, in nanoseconds, to sample master and slave clocks. More...

Glib::PropertyProxy< int >	property_window_size ()
	The size of the window used to calculate rate and offset. More...

Glib::PropertyProxy_ReadOnly< int >	property_window_size () const
	The size of the window used to calculate rate and offset. More...

Glib::PropertyProxy< int >	property_window_threshold ()
	The threshold to start calculating rate and offset. More...

Glib::PropertyProxy_ReadOnly< int >	property_window_threshold () const
	The threshold to start calculating rate and offset. More...

virtual Gst::ClockTime	change_resolution_vfunc (Gst::ClockTime old_resolution, Gst::ClockTime new_resolution)
	Change the resolution of the clock. More...

virtual Gst::ClockTime	get_resolution_vfunc () const
	Get the resolution of the clock. More...

virtual Gst::ClockTime	get_internal_time_vfunc () const
	Get the internal unadjusted time of the clock. More...

virtual ClockReturn	wait_vfunc (const Glib::RefPtr< Gst::ClockID >& id, Gst::ClockTimeDiff& jitter)
	Perform a blocking wait for the given Gst::ClockID. More...

virtual ClockReturn	wait_async_vfunc (const Glib::RefPtr< Gst::ClockID >& id)
	Perform an asynchronous wait for the given Gst::ClockID. More...

virtual void	unschedule_vfunc (const Glib::RefPtr< Gst::ClockID >& id)
	Unblock a blocking or async wait operation. More...

Glib::SignalProxy< void, bool >	signal_synced ()

Public Member Functions inherited from Gst::Object
	Object (Object&& src) noexcept

Object&	operator= (Object&& src) noexcept

	~Object () noexcept override

GstObject*	gobj ()
	Provides access to the underlying C GObject. More...

const GstObject*	gobj () const
	Provides access to the underlying C GObject. More...

GstObject*	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

bool	is_element () const

bool	is_element_factory () const

bool	is_pad () const

bool	is_pad_template () const

bool	is_bin () const

guint32	get_flags () const
	Returns the entire set of flags for the object. More...

bool	set_name (const Glib::ustring& name)
	Sets the name of object, or gives object a guaranteed unique name (if name is `nullptr`). More...

Glib::ustring	get_name () const
	Returns a copy of the name of object. More...

bool	set_parent (const Glib::RefPtr< Gst::Object >& parent)
	Sets the parent of object to parent. More...

Glib::RefPtr< Gst::Object >	get_parent ()
	Returns the parent of object. More...

Glib::RefPtr< const Gst::Object >	get_parent () const
	Returns the parent of object. More...

void	unparent ()
	Clear the parent of object, removing the associated reference. More...

void	set_control_rate (Gst::ClockTime control_rate)
	Change the control-rate for this object. More...

Gst::ClockTime	get_control_rate () const
	Obtain the control-rate for this object. More...

Gst::ClockTime	suggest_next_sync () const
	Returns a suggestion for timestamps where buffers should be split to get best controller results. More...

bool	sync_values (Gst::ClockTime timestamp)
	Sets the properties of the object, according to the Gst::ControlSources that (maybe) handle them and for the given timestamp. More...

void	set_control_bindings_disabled (bool disabled)
	This function is used to disable all controlled properties of the object for some time, i.e. sync_values() will do nothing. More...

bool	has_asctive_control_bindings () const
	Check if the object has an active controlled properties. More...

bool	has_ancestor (const Glib::RefPtr< const Gst::Object >& ancestor) const
	Check if object has an ancestor ancestor somewhere up in the hierarchy. More...

bool	has_as_ancestor (const Glib::RefPtr< Gst::Object >& ancestor) const
	Check if object has an ancestor ancestor somewhere up in the hierarchy. More...

bool	has_as_parent (const Glib::RefPtr< Gst::Object >& parent) const
	Check if parent is the parent of object. More...

Glib::ustring	get_path_string ()
	Generates a string describing the path of object in the object hierarchy. More...

Glib::PropertyProxy< Glib::ustring >	property_name ()
	The name of the object. More...

Glib::PropertyProxy_ReadOnly< Glib::ustring >	property_name () const
	The name of the object. More...

Glib::PropertyProxy< Glib::RefPtr< Gst::Object > >	property_parent ()
	The parent of the object. More...

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gst::Object > >	property_parent () const
	The parent of the object. More...

Glib::SignalProxy< void, const Glib::RefPtr< Gst::Object >&, GParamSpec*>	signal_deep_notify ()

int	get_refcount () const

Static Public Member Functions
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system. More...

Static Public Member Functions inherited from Gst::Object
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system. More...

static bool	check_uniqueness (const Glib::ListHandle< const Gst::Object >& list, const Glib::ustring& name)
	Checks to see if there is any object named name in list. More...

Related Functions
(Note that these are not member functions.)
Glib::RefPtr< Gst::Clock >	wrap (GstClock* object, bool take_copy=false)
	A Glib::wrap() method for this object. More...

Related Functions inherited from Gst::Object
Glib::RefPtr< Gst::Object >	wrap (GstObject* object, bool take_copy=false)
	A Glib::wrap() method for this object. More...

Additional Inherited Members
Protected Member Functions inherited from Gst::Object
virtual void	on_deep_notify (const Glib::RefPtr< Gst::Object >& prop_object, GParamSpec* prop)
	This is a default handler for the signal signal_deep_notify(). More...

Detailed Description

Abstract class for global clocks GStreamer uses a global clock to synchronize the plugins in a pipeline.

Different clock implementations are possible by implementing this abstract base class.

The Gst::Clock returns a monotonically increasing time with the method 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 newsegment events and the element's base time, see Gst::Pipeline.

A clock implementation can support periodic and single shot clock notifications both synchronous and asynchronous.

One first needs to create a Gst::ClockID for the periodic or single shot notification using create_single_shot_id() or create_periodic_id().

To perform a blocking wait for the specific time of the Gst::ClockID use the Gst::ClockID::wait(). To receive a callback when the specific time is reached in the clock use Gst::ClockID::wait_async(). Both these calls can be interrupted with the Gst::ClockID::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 it is unscheduled. To schedule a sync periodic callback, Gst::ClockID::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 Gst::ClockID that has been unscheduled cannot be used again for any wait operation, a new Gst::ClockID should be created.

It is possible to perform a blocking wait on the same Gst::ClockID from multiple threads. However, registering the same Gst::ClockID 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 Gst::ClockID, 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 Gst::ClockID has to keep a handle to the Gst::ClockID 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. (The RefPtr takes care of

* unreffing in this case)

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 Gst::Clock with the 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 set_calibration(). This feature is mostly useful for plugins that have an internal clock but must operate with another clock selected by the Gst::Pipeline. They can track the offset and rate difference of their internal clock relative to the master clock by using the get_calibration() method.

The master/slave synchronisation can be tuned with the "timeout", "window-size" and "window-threshold" properties. The "timeout" property defines the interval to sample the master clock and run the calibration functions. "window-size" defines the number of samples to use when calibrating and "window-threshold" defines the minimum number of samples before the calibration is performed.

Last reviewed on 2016-05-16 (1.8.0)

Constructor & Destructor Documentation

◆ Clock()

Gst::Clock::Clock ( Clock&& src )

noexcept

◆ ~Clock()

Gst::Clock::~Clock ( )

overridenoexcept

Member Function Documentation

◆ add_observation() [1/2]

bool Gst::Clock::add_observation	(	Gst::ClockTime	slave_time,
		Gst::ClockTime	master_time,
		gdouble &	result
	)

The time master_time of the master clock and the time slave_time 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, result 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.

Parameters

slave_time	A time on the slave.
master_time	A time on the master.
result	A pointer to hold the result.

Returns: true if enough observations were added to run the regression algorithm.

MT safe.

◆ add_observation() [2/2]

bool Gst::Clock::add_observation	(	Gst::ClockTime	slave_time,
		Gst::ClockTime	master_time,
		gdouble &	result,
		Gst::ClockTime&	internal,
		Gst::ClockTime&	external,
		Gst::ClockTime&	rate_num,
		Gst::ClockTime&	rate_denom
	)

Add a clock observation to the internal slaving algorithm the same as 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 set_calibration() with the values, or some modified version of them.

Parameters

slave_time	A time on the slave.
master_time	A time on the master.
result	A pointer to hold the result.
internal	A location to store the internal time.
external	A location to store the external time.
rate_num	A location to store the rate numerator.
rate_denom	A location to store the rate denominator.

◆ adjust_unlocked()

Gst::ClockTime Gst::Clock::adjust_unlocked ( Gst::ClockTime internal_time )

Converts the given internal_time clock time to the external time, adjusting for the rate and reference time set with 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 unadjust_unlocked().

Parameters

internal_time A clock time.

Returns: The converted time of the clock.

◆ adjust_with_calibration()

Gst::ClockTime Gst::Clock::adjust_with_calibration	(	Gst::ClockTime	internal_target,
		Gst::ClockTime	cinternal,
		Gst::ClockTime	cexternal,
		Gst::ClockTime	cnum,
		Gst::ClockTime	cdenom
	)

Converts the given internal_target clock time to the external time, using the passed calibration parameters.

This function performs the same calculation as adjust_unlocked() when called using the current calibration parameters, but doesn't ensure a monotonically increasing result as adjust_unlocked() does.

Note: The clock parameter is unused and can be nullptr

Parameters

internal_target	A clock time.
cinternal	A reference internal time.
cexternal	A reference external time.
cnum	The numerator of the rate of the clock relative to its internal time.
cdenom	The denominator of the rate of the clock.

Returns: The converted time of the clock.

◆ change_resolution_vfunc()

virtual Gst::ClockTime Gst::Clock::change_resolution_vfunc	(	Gst::ClockTime	old_resolution,
		Gst::ClockTime	new_resolution
	)

virtual

Change the resolution of the clock.

Not all values might be acceptable. The new resolution should be returned.

◆ create_periodic_id()

Glib::RefPtr<Gst::ClockID> Gst::Clock::create_periodic_id	(	Gst::ClockTime	start_time,
		Gst::ClockTime	intervals
	)

Get 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 intervals. id should be unreffed after usage.

Free-function: gst_clock_id_unref

Parameters

start_time	The requested start time.
intervals	The requested interval.

Returns: A Gst::ClockID that can be used to request the time notification.

MT safe.

◆ create_single_shot_id()

Glib::RefPtr<Gst::ClockID> Gst::Clock::create_single_shot_id ( Gst::ClockTime time )

Get a Gst::ClockID from clock to trigger a single shot notification at the requested time.

The single shot id should be unreffed after usage.

Free-function: gst_clock_id_unref

Parameters

time	The requested time.

Returns: A Gst::ClockID that can be used to request the time notification.

MT safe.

◆ get_calibration()

void Gst::Clock::get_calibration	(	Gst::ClockTime&	internal,
		Gst::ClockTime&	external,
		Gst::ClockTime&	rate_num,
		Gst::ClockTime&	rate_denom
	)		const

Gets the internal rate and reference time of clock.

See set_calibration() for more information.

internal, external, rate_num, and rate_denom can be left nullptr if the caller is not interested in the values.

MT safe.

Parameters

internal	A location to store the internal time.
external	A location to store the external time.
rate_num	A location to store the rate numerator.
rate_denom	A location to store the rate denominator.

◆ get_internal_time()

Gst::ClockTime Gst::Clock::get_internal_time ( ) const

Gets the current internal time of the given clock.

The time is returned unadjusted for the offset and the rate.

Returns: The internal time of the clock. Or GST_CLOCK_TIME_NONE when given invalid input.

MT safe.

◆ get_internal_time_vfunc()

virtual Gst::ClockTime Gst::Clock::get_internal_time_vfunc ( ) const

virtual

Get the internal unadjusted time of the clock.

◆ get_master() [1/2]

Glib::RefPtr<Gst::Clock> Gst::Clock::get_master ( )

Get the master clock that clock is slaved to or nullptr when the clock is not slaved to any master clock.

Returns: A master Gst::Clock or nullptr when this clock is not slaved to a master clock. Unref after usage.

MT safe.

◆ get_master() [2/2]

Glib::RefPtr<const Gst::Clock> Gst::Clock::get_master ( ) const

Get the master clock that clock is slaved to or nullptr when the clock is not slaved to any master clock.

Returns: A master Gst::Clock or nullptr when this clock is not slaved to a master clock. Unref after usage.

MT safe.

◆ get_resolution()

Gst::ClockTime Gst::Clock::get_resolution ( ) const

Get the accuracy of the clock.

The accuracy of the clock is the granularity of the values returned by get_time().

Returns: The resolution of the clock in units of Gst::ClockTime.

MT safe.

◆ get_resolution_vfunc()

virtual Gst::ClockTime Gst::Clock::get_resolution_vfunc ( ) const

virtual

Get the resolution of the clock.

◆ get_time()

Gst::ClockTime Gst::Clock::get_time ( ) const

Gets the current time of the given clock.

The time is always monotonically increasing and adjusted according to the current offset and rate.

Returns: The time of the clock. Or GST_CLOCK_TIME_NONE when given invalid input.

MT safe.

◆ get_type()

static GType Gst::Clock::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

◆ gobj() [1/2]

GstClock* Gst::Clock::gobj ( )

inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

const GstClock* Gst::Clock::gobj ( ) const

inline

Provides access to the underlying C GObject.

◆ gobj_copy()

GstClock* Gst::Clock::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ is_synced()

bool Gst::Clock::is_synced ( ) const

Checks if the clock is currently synced.

This returns if GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC is not set on the clock.

Returns: true if the clock is currently synced.

◆ operator=()

Clock& Gst::Clock::operator= ( Clock&& src )

noexcept

◆ periodic_id_reinit()

bool Gst::Clock::periodic_id_reinit	(	const Glib::RefPtr< Gst::ClockID >&	id,
		Gst::ClockTime	start_time,
		Gst::ClockTime	interval
	)

Reinitializes the provided periodic id to the provided start time and interval.

Does not modify the reference count.

Parameters

id	A Gst::ClockID.
start_time	The requested start time.
interval	The requested interval.

Returns: true if the GstClockID could be reinitialized to the provided time, else false.

◆ property_timeout() [1/2]

Glib::PropertyProxy< guint64 > Gst::Clock::property_timeout ( )

get/set timeout can be achieved through 'timeout' property, so wrapping gst_clock_{get|set|_timeout is unnecessary.

The amount of time, in nanoseconds, to sample master and slave clocks.

Returns: A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.

◆ property_timeout() [2/2]

Glib::PropertyProxy_ReadOnly< guint64 > Gst::Clock::property_timeout ( ) const

The amount of time, in nanoseconds, to sample master and slave clocks.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_window_size() [1/2]

Glib::PropertyProxy< int > Gst::Clock::property_window_size ( )

The size of the window used to calculate rate and offset.

Returns: A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.

◆ property_window_size() [2/2]

Glib::PropertyProxy_ReadOnly< int > Gst::Clock::property_window_size ( ) const

The size of the window used to calculate rate and offset.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_window_threshold() [1/2]

Glib::PropertyProxy< int > Gst::Clock::property_window_threshold ( )

The threshold to start calculating rate and offset.

Returns: A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.

◆ property_window_threshold() [2/2]

Glib::PropertyProxy_ReadOnly< int > Gst::Clock::property_window_threshold ( ) const

The threshold to start calculating rate and offset.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ set_calibration()

void Gst::Clock::set_calibration	(	Gst::ClockTime	internal,
		Gst::ClockTime	external,
		Gst::ClockTime	rate_num,
		Gst::ClockTime	rate_denom
	)

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 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 get_internal_time() when this function is called.

Subsequent calls to get_time() will return clock times computed as follows:

time = (internal_time - internal) * rate_num / rate_denom + external

This formula is implemented in adjust_unlocked(). Of course, it tries to do the integer arithmetic as precisely as possible.

Note that get_time() always returns increasing values so when you move the clock backwards, get_time() will report the previous value until the clock catches up.

MT safe.

Parameters

internal	A reference internal time.
external	A reference external time.
rate_num	The numerator of the rate of the clock relative to its internal time.
rate_denom	The denominator of the rate of the clock.

◆ set_master()

bool Gst::Clock::set_master ( const Clock& master_clock )

Set master_clock as the master clock for clock.

clock will be automatically calibrated so that 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 get_calibration().

master_clock can be nullptr 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.

Parameters

master_clock A master Gst::Clock.

Returns: true if the clock is capable of being slaved to a master clock. Trying to set a master on a clock without the Gst::CLOCK_FLAG_CAN_SET_MASTER flag will make this function return false.

MT safe.

◆ set_resolution()

Gst::ClockTime Gst::Clock::set_resolution ( Gst::ClockTime resolution )

Set 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.

Parameters

resolution The resolution to set.

Returns: The new resolution of the clock.

◆ set_synced()

void Gst::Clock::set_synced ( bool synced )

Sets clock to synced and emits the GstClock::synced signal, and wakes up any thread waiting in 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.

Parameters

synced If the clock is synced.

◆ signal_synced()

Glib::SignalProxy< void,bool > Gst::Clock::signal_synced ( )

Slot Prototype:: void on_my_synced(bool synced)

Signaled on clocks with GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC set once the clock is synchronized, or when it completely lost synchronization. This signal will not be emitted on clocks without the flag.

This signal will be emitted from an arbitrary thread, most likely not the application's main thread.

Parameters

synced If the clock is synced now.

◆ single_shot_id_reinit()

bool Gst::Clock::single_shot_id_reinit	(	const Glib::RefPtr< Gst::ClockID >&	id,
		Gst::ClockTime	time
	)

Reinitializes the provided single shot id to the provided time.

Does not modify the reference count.

Parameters

id	A Gst::ClockID.
time	The requested time.

Returns: true if the GstClockID could be reinitialized to the provided time, else false.

◆ unadjust_unlocked()

Gst::ClockTime Gst::Clock::unadjust_unlocked ( Gst::ClockTime external_time )

Converts the given external_time clock time to the internal time of clock, using the rate and reference time set with 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 adjust_unlocked().

Parameters

external_time An external clock time.

Returns: The internal time of the clock corresponding to external_time.

◆ unadjust_with_calibration()

Gst::ClockTime Gst::Clock::unadjust_with_calibration	(	Gst::ClockTime	external_target,
		Gst::ClockTime	cinternal,
		Gst::ClockTime	cexternal,
		Gst::ClockTime	cnum,
		Gst::ClockTime	cdenom
	)

Converts the given external_target clock time to the internal time, using the passed calibration parameters.

This function performs the same calculation as unadjust_unlocked() when called using the current calibration parameters.

Note: The clock parameter is unused and can be nullptr

Parameters

external_target	A clock time.
cinternal	A reference internal time.
cexternal	A reference external time.
cnum	The numerator of the rate of the clock relative to its internal time.
cdenom	The denominator of the rate of the clock.

Returns: The converted time of the clock.

◆ unschedule_vfunc()

virtual void Gst::Clock::unschedule_vfunc ( const Glib::RefPtr< Gst::ClockID >& id )

virtual

Unblock a blocking or async wait operation.

◆ wait_async_vfunc()

virtual ClockReturn Gst::Clock::wait_async_vfunc ( const Glib::RefPtr< Gst::ClockID >& id )

virtual

Perform an asynchronous wait for the given Gst::ClockID.

◆ wait_for_sync()

bool Gst::Clock::wait_for_sync ( Gst::ClockTime timeout )

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.

Parameters

timeout Timeout for waiting or Gst::CLOCK_TIME_NONE.

Returns: true if waiting was successful, or false on timeout.

◆ wait_vfunc()

virtual ClockReturn Gst::Clock::wait_vfunc	(	const Glib::RefPtr< Gst::ClockID >&	id,
		Gst::ClockTimeDiff&	jitter
	)

virtual

Perform a blocking wait for the given Gst::ClockID.

Deprecated, implement wait_jitter_vfunc() instead.

Friends And Related Function Documentation

◆ wrap()

Glib::RefPtr< Gst::Clock > wrap	(	GstClock *	object,
		bool	take_copy = `false`
	)

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

Public Member Functions

Static Public Member Functions

Related Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Clock()

◆ ~Clock()

Member Function Documentation

◆ add_observation() [1/2]

◆ add_observation() [2/2]

◆ adjust_unlocked()

◆ adjust_with_calibration()

◆ change_resolution_vfunc()

◆ create_periodic_id()

◆ create_single_shot_id()

◆ get_calibration()

◆ get_internal_time()

◆ get_internal_time_vfunc()

◆ get_master() [1/2]

◆ get_master() [2/2]

◆ get_resolution()

◆ get_resolution_vfunc()

◆ get_time()

◆ get_type()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ is_synced()

◆ operator=()

◆ periodic_id_reinit()

◆ property_timeout() [1/2]

◆ property_timeout() [2/2]

◆ property_window_size() [1/2]

◆ property_window_size() [2/2]

◆ property_window_threshold() [1/2]

◆ property_window_threshold() [2/2]

◆ set_calibration()

◆ set_master()

◆ set_resolution()

◆ set_synced()

◆ signal_synced()

◆ single_shot_id_reinit()

◆ unadjust_unlocked()

◆ unadjust_with_calibration()

◆ unschedule_vfunc()

◆ wait_async_vfunc()

◆ wait_for_sync()

◆ wait_vfunc()

Friends And Related Function Documentation

◆ wrap()