GstControlBinding: GStreamer 1.0 Core Reference Manual

GstControlBinding

GstControlBinding — attachment for control source sources

Functions

gboolean	gst_control_binding_sync_values ()
GValue *	gst_control_binding_get_value ()
gboolean	gst_control_binding_get_value_array ()
gboolean	gst_control_binding_get_g_value_array ()
void	gst_control_binding_set_disabled ()
gboolean	gst_control_binding_is_disabled ()

Properties

gchar *	name	Read / Write / Construct Only
GstObject *	object	Read / Write / Construct Only

Types and Values

struct	GstControlBinding
struct	GstControlBindingClass

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstControlBinding

Includes

#include <gst/gst.h>

Description

A base class for value mapping objects that attaches control sources to gobject properties. Such an object is taking one or more GstControlSource instances, combines them and maps the resulting value to the type and value range of the bound property.

Functions

gst_control_binding_sync_values ()

gboolean
gst_control_binding_sync_values (GstControlBinding *binding,
                                 GstObject *object,
                                 GstClockTime timestamp,
                                 GstClockTime last_sync);

Sets the property of the object , according to the GstControlSources that 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.

Parameters

binding	the control binding
object	the object that has controlled properties
timestamp	the time that should be processed
last_sync	the last time this was called

Returns

TRUE if the controller value could be applied to the object property, FALSE otherwise

gst_control_binding_get_value ()

GValue *
gst_control_binding_get_value (GstControlBinding *binding,
                               GstClockTime timestamp);

Gets the value for the given controlled property at the requested time.

Parameters

binding	the control binding
timestamp	the time the control-change should be read from

Returns

the GValue of the property at the given time, or NULL if the property isn't controlled.

[nullable]

gst_control_binding_get_value_array ()

gboolean
gst_control_binding_get_value_array (GstControlBinding *binding,
                                     GstClockTime timestamp,
                                     GstClockTime interval,
                                     guint n_values,
                                     gpointer values);

Gets a number of values for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of the same type as the objects property's type.

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 values are unboxed and ready to be used. The similar function gst_control_binding_get_g_value_array() returns the array as GValues and is more suitable for bindings.

[skip]

Parameters

binding	the control binding
timestamp	the time that should be processed
interval	the time spacing between subsequent values
n_values	the number of values
values	array to put control-values in.	[array length=n_values]

Returns

TRUE if the given array could be filled, FALSE otherwise

gst_control_binding_get_g_value_array ()

gboolean
gst_control_binding_get_g_value_array (GstControlBinding *binding,
                                       GstClockTime timestamp,
                                       GstClockTime interval,
                                       guint n_values,
                                       GValue *values);

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.

Parameters

binding	the control binding
timestamp	the time that should be processed
interval	the time spacing between subsequent values
n_values	the number of values
values	array to put control-values in.	[array length=n_values]

Returns

TRUE if the given array could be filled, FALSE otherwise

gst_control_binding_set_disabled ()

void
gst_control_binding_set_disabled (GstControlBinding *binding,
                                  gboolean disabled);

This function is used to disable a control binding for some time, i.e. gst_object_sync_values() will do nothing.

Parameters

binding	the control binding
disabled	boolean that specifies whether to disable the controller or not.

gst_control_binding_is_disabled ()

gboolean
gst_control_binding_is_disabled (GstControlBinding *binding);

Check if the control binding is disabled.

Parameters

binding

the control binding

Returns

TRUE if the binding is inactive

Types and Values

struct GstControlBinding

struct GstControlBinding {
  gchar *name;
  GParamSpec *pspec;
};

The instance structure of GstControlBinding.

Members

gchar *`name`;	name of the property of this binding
GParamSpec *`pspec`;	GParamSpec for this property

struct GstControlBindingClass

struct GstControlBindingClass {
  GstObjectClass parent_class;

  gboolean (* sync_values) (GstControlBinding *binding, GstObject *object, GstClockTime timestamp, GstClockTime last_sync);
  GValue * (* get_value) (GstControlBinding *binding, GstClockTime timestamp);
  gboolean (* get_value_array) (GstControlBinding *binding, GstClockTime timestamp,GstClockTime interval, guint n_values, gpointer values);
  gboolean (* get_g_value_array) (GstControlBinding *binding, GstClockTime timestamp,GstClockTime interval, guint n_values, GValue *values);
};

The class structure of GstControlBinding.

Members

`sync_values` ()	implementation for updating the target values
`get_value` ()	implementation to fetch a single control-value
`get_value_array` ()	implementation to fetch a series of control-values
`get_g_value_array` ()	implementation to fetch a series of control-values as g_values

Property Details

The `“name”` property

  “name”                     gchar *

The name of the property.

Flags: Read / Write / Construct Only

Default value: NULL

The `“object”` property

  “object”                   GstObject *

The object of the property.

Flags: Read / Write / Construct Only