GstTimedValueControlSource: GStreamer 1.0 Library Reference Manual

GstTimedValueControlSource

GstTimedValueControlSource — timed value control source base class

Functions

GSequenceIter *	gst_timed_value_control_source_find_control_point_iter ()
gboolean	gst_timed_value_control_source_set ()
gboolean	gst_timed_value_control_source_set_from_list ()
GList *	gst_timed_value_control_source_get_all ()
gboolean	gst_timed_value_control_source_unset ()
void	gst_timed_value_control_source_unset_all ()
gint	gst_timed_value_control_source_get_count ()
void	gst_timed_value_control_invalidate_cache ()

Signals

void	value-added	Run First
void	value-changed	Run First
void	value-removed	Run First

Types and Values

struct	GstTimedValueControlSource
struct	GstControlPoint

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstControlSource
                ╰── GstTimedValueControlSource
                    ├── GstInterpolationControlSource
                    ╰── GstTriggerControlSource

Includes

#include <libs/controller/gsttimedvaluecontrolsource.h>

Description

Base class for GstControlSource that use time-stamped values.

When overriding bind, chain up first to give this bind implementation a chance to setup things.

All functions are MT-safe.

Functions

gst_timed_value_control_source_find_control_point_iter ()

GSequenceIter *
gst_timed_value_control_source_find_control_point_iter
                               (GstTimedValueControlSource *self,
                                GstClockTime timestamp);

Find last value before given timestamp in control point list. If all values in the control point list come after the given timestamp or no values exist, NULL is returned.

For use in control source implementations.

Parameters

self	the control source to search in
timestamp	the search key

Returns

the found GSequenceIter or NULL.

[transfer none]

gst_timed_value_control_source_set ()

gboolean
gst_timed_value_control_source_set (GstTimedValueControlSource *self,
                                    GstClockTime timestamp,
                                    const gdouble value);

Set the value of given controller-handled property at a certain time.

Parameters

self	the GstTimedValueControlSource object
timestamp	the time the control-change is scheduled for
value	the control-value

Returns

FALSE if the values couldn't be set, TRUE otherwise.

gst_timed_value_control_source_set_from_list ()

gboolean
gst_timed_value_control_source_set_from_list
                               (GstTimedValueControlSource *self,
                                const GSList *timedvalues);

Sets multiple timed values at once.

Parameters

self	the GstTimedValueControlSource object
timedvalues	a list with GstTimedValue items.	[transfer none][element-type GstTimedValue]

Returns

FALSE if the values couldn't be set, TRUE otherwise.

gst_timed_value_control_source_get_all ()

GList *
gst_timed_value_control_source_get_all
                               (GstTimedValueControlSource *self);

Returns a read-only copy of the list of GstTimedValue for the given property. Free the list after done with it.

Parameters

self

the GstTimedValueControlSource to get the list from

Returns

a copy of the list, or NULL if the property isn't handled by the controller.

[transfer container][element-type GstTimedValue]

gst_timed_value_control_source_unset ()

gboolean
gst_timed_value_control_source_unset (GstTimedValueControlSource *self,
                                      GstClockTime timestamp);

Used to remove the value of given controller-handled property at a certain time.

Parameters

self	the GstTimedValueControlSource object
timestamp	the time the control-change should be removed from

Returns

FALSE if the value couldn't be unset (i.e. not found, TRUE otherwise.

gst_timed_value_control_source_unset_all ()

void
gst_timed_value_control_source_unset_all
                               (GstTimedValueControlSource *self);

Used to remove all time-stamped values of given controller-handled property

Parameters

self

the GstTimedValueControlSource object

gst_timed_value_control_source_get_count ()

gint
gst_timed_value_control_source_get_count
                               (GstTimedValueControlSource *self);

Get the number of control points that are set.

Parameters

self

the GstTimedValueControlSource to get the number of values from

Returns

the number of control points that are set.

gst_timed_value_control_invalidate_cache ()

void
gst_timed_value_control_invalidate_cache
                               (GstTimedValueControlSource *self);

Reset the controlled value cache.

Parameters

self

the GstTimedValueControlSource

Types and Values

struct GstTimedValueControlSource

struct GstTimedValueControlSource;

The instance structure of GstControlSource.

struct GstControlPoint

struct GstControlPoint {
  /* fields from GstTimedValue. DO NOT CHANGE! */
  GstClockTime timestamp;
  gdouble value;
};

An internal structure for value+time and various temporary values used for interpolation. This "inherits" from GstTimedValue.

Members

GstClockTime `timestamp`;	timestamp of the value change
gdouble `value`;	the new value

Signal Details

The `“value-added”` signal

void
user_function (GstTimedValueControlSource *self,
               GstControlPoint            *timed_value,
               gpointer                    user_data)

Emited right after the new value has been added to self

Parameters

self	The GstTimedValueControlSource into which a GstTimedValue has been added
timed_value	The newly added GstTimedValue
user_data	user data set when the signal handler was connected.

Flags: Run First

Since: 1.6

The `“value-changed”` signal

void
user_function (GstTimedValueControlSource *self,
               GstControlPoint            *timed_value,
               gpointer                    user_data)

Emited right after the new value has been set on timed_signals

Parameters

self	The GstTimedValueControlSource on which a GstTimedValue has changed
timed_value	The GstTimedValue where the value changed
user_data	user data set when the signal handler was connected.

Flags: Run First

Since: 1.6

The `“value-removed”` signal

void
user_function (GstTimedValueControlSource *self,
               GstControlPoint            *timed_value,
               gpointer                    user_data)

Emited when timed_value is removed from self

Parameters

self	The GstTimedValueControlSource from which a GstTimedValue has been removed
timed_value	The removed GstTimedValue
user_data	user data set when the signal handler was connected.

Flags: Run First

Since: 1.6