gst/gstcontrolbinding.c - mtk-gstreamer-debian - Git at Google

 /* GStreamer
  *
  * Copyright (C) 2011 Stefan Sauer <ensonic@users.sf.net>
  *
  * gstcontrolbinding.c: Attachment for control sources
  *
  * 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., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 /**
  * SECTION:gstcontrolbinding
  * @short_description: attachment for control source sources
  *
  * 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.
  */
 /* FIXME(ensonic): should we make gst_object_add_control_binding() internal
  * - we create the control_binding for a certain object anyway
  * - we could call gst_object_add_control_binding() at the end of
  *   gst_control_binding_constructor()
  * - the weak-ref on object is not nice, as is the same as gst_object_parent()
  *   once the object is added to the parent
  *
  * - another option would be to defer what is done in _constructor to when
  *   the parent is set (need to listen to the signal then)
  *   then basically I could
  *   a) remove the obj arg and wait the binding to be added or
  *   b) add the binding from constructor, unref object there and make obj
  *      writeonly
  */

 #include "gst_private.h"

 #include <glib-object.h>
 #include <gst/gst.h>

 #include "gstcontrolbinding.h"

 #include <math.h>

 #define GST_CAT_DEFAULT control_binding_debug
 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

 #define _do_init \
   GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "gstcontrolbinding", 0, \
       "dynamic parameter control source attachment");

 static GObject *gst_control_binding_constructor (GType type,
     guint n_construct_params, GObjectConstructParam * construct_params);
 static void gst_control_binding_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
 static void gst_control_binding_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
 static void gst_control_binding_dispose (GObject * object);
 static void gst_control_binding_finalize (GObject * object);

 G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstControlBinding, gst_control_binding,
     GST_TYPE_OBJECT, _do_init);

 enum
 {
   PROP_0,
   PROP_OBJECT,
   PROP_NAME,
   PROP_LAST
 };

 static GParamSpec *properties[PROP_LAST];

 static void
 gst_control_binding_class_init (GstControlBindingClass * klass)
 {
   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

   gobject_class->constructor = gst_control_binding_constructor;
   gobject_class->set_property = gst_control_binding_set_property;
   gobject_class->get_property = gst_control_binding_get_property;
   gobject_class->dispose = gst_control_binding_dispose;
   gobject_class->finalize = gst_control_binding_finalize;

   properties[PROP_OBJECT] =
       g_param_spec_object ("object", "Object",
       "The object of the property", GST_TYPE_OBJECT,
       G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);

   properties[PROP_NAME] =
       g_param_spec_string ("name", "Name", "The name of the property", NULL,
       G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);


   g_object_class_install_properties (gobject_class, PROP_LAST, properties);
 }

 static void
 gst_control_binding_init (GstControlBinding * binding)
 {
 }

 static GObject *
 gst_control_binding_constructor (GType type, guint n_construct_params,
     GObjectConstructParam * construct_params)
 {
   GstControlBinding *binding;
   GParamSpec *pspec;

   binding =
       GST_CONTROL_BINDING (G_OBJECT_CLASS (gst_control_binding_parent_class)
       ->constructor (type, n_construct_params, construct_params));

   GST_INFO_OBJECT (binding->object, "trying to put property '%s' under control",
       binding->name);

   /* check if the object has a property of that name */
   if ((pspec =
           g_object_class_find_property (G_OBJECT_GET_CLASS (binding->object),
               binding->name))) {
     GST_DEBUG_OBJECT (binding->object, "  psec->flags : 0x%08x", pspec->flags);

     /* check if this param is witable && controlable && !construct-only */
     if ((pspec->flags & (G_PARAM_WRITABLE | GST_PARAM_CONTROLLABLE |
                 G_PARAM_CONSTRUCT_ONLY)) ==
         (G_PARAM_WRITABLE | GST_PARAM_CONTROLLABLE)) {
       binding->pspec = pspec;
     } else {
       GST_WARNING_OBJECT (binding->object,
           "property '%s' on class '%s' needs to "
           "be writeable, controlable and not construct_only", binding->name,
           G_OBJECT_TYPE_NAME (binding->object));
     }
   } else {
     GST_WARNING_OBJECT (binding->object, "class '%s' has no property '%s'",
         G_OBJECT_TYPE_NAME (binding->object), binding->name);
   }
   return (GObject *) binding;
 }

 static void
 gst_control_binding_dispose (GObject * object)
 {
   GstControlBinding *self = GST_CONTROL_BINDING (object);

   /* we did not took a reference */
   g_object_remove_weak_pointer ((GObject *) self->object,
       (gpointer *) & self->object);
   self->object = NULL;

   ((GObjectClass *) gst_control_binding_parent_class)->dispose (object);
 }

 static void
 gst_control_binding_finalize (GObject * object)
 {
   GstControlBinding *self = GST_CONTROL_BINDING (object);

   g_free (self->name);

   ((GObjectClass *) gst_control_binding_parent_class)->finalize (object);
 }

 static void
 gst_control_binding_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
   GstControlBinding *self = GST_CONTROL_BINDING (object);

   switch (prop_id) {
     case PROP_OBJECT:
       /* do not ref to avoid a ref cycle */
       self->object = g_value_get_object (value);
       g_object_add_weak_pointer ((GObject *) self->object,
           (gpointer *) & self->object);
       break;
     case PROP_NAME:
       self->name = g_value_dup_string (value);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static void
 gst_control_binding_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
   GstControlBinding *self = GST_CONTROL_BINDING (object);

   switch (prop_id) {
     case PROP_OBJECT:
       g_value_set_object (value, self->object);
       break;
     case PROP_NAME:
       g_value_set_string (value, self->name);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 /* functions */

 /**
  * gst_control_binding_sync_values:
  * @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
  *
  * 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.
  *
  * Returns: %TRUE if the controller value could be applied to the object
  * property, %FALSE otherwise
  */
 gboolean
 gst_control_binding_sync_values (GstControlBinding * binding,
     GstObject * object, GstClockTime timestamp, GstClockTime last_sync)
 {
   GstControlBindingClass *klass;
   gboolean ret = FALSE;

   g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);

   if (binding->disabled)
     return TRUE;

   klass = GST_CONTROL_BINDING_GET_CLASS (binding);

   if (G_LIKELY (klass->sync_values != NULL)) {
     ret = klass->sync_values (binding, object, timestamp, last_sync);
   } else {
     GST_WARNING_OBJECT (binding, "missing sync_values implementation");
   }
   return ret;
 }

 /**
  * gst_control_binding_get_value:
  * @binding: the control binding
  * @timestamp: the time the control-change should be read from
  *
  * Gets the value for the given controlled property at the requested time.
  *
  * Returns: (nullable): the GValue of the property at the given time,
  * or %NULL if the property isn't controlled.
  */
 GValue *
 gst_control_binding_get_value (GstControlBinding * binding,
     GstClockTime timestamp)
 {
   GstControlBindingClass *klass;
   GValue *ret = NULL;

   g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), NULL);
   g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);

   klass = GST_CONTROL_BINDING_GET_CLASS (binding);

   if (G_LIKELY (klass->get_value != NULL)) {
     ret = klass->get_value (binding, timestamp);
   } else {
     GST_WARNING_OBJECT (binding, "missing get_value implementation");
   }
   return ret;
 }

 /**
  * gst_control_binding_get_value_array: (skip)
  * @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 length=n_values): array to put control-values in
  *
  * 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.
  *
  * Returns: %TRUE if the given array could be filled, %FALSE otherwise
  */
 gboolean
 gst_control_binding_get_value_array (GstControlBinding * binding,
     GstClockTime timestamp, GstClockTime interval, guint n_values,
     gpointer values)
 {
   GstControlBindingClass *klass;
   gboolean ret = FALSE;

   g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
   g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
   g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
   g_return_val_if_fail (values, FALSE);

   klass = GST_CONTROL_BINDING_GET_CLASS (binding);

   if (G_LIKELY (klass->get_value_array != NULL)) {
     ret =
         klass->get_value_array (binding, timestamp, interval, n_values, values);
   } else {
     GST_WARNING_OBJECT (binding, "missing get_value_array implementation");
   }
   return ret;
 }

 #define CONVERT_ARRAY(type,TYPE) \
 { \
   g##type *v = g_new (g##type,n_values); \
   ret = gst_control_binding_get_value_array (binding, timestamp, interval, \
       n_values, v); \
   if (ret) { \
     for (i = 0; i < n_values; i++) { \
       g_value_init (&values[i], G_TYPE_##TYPE); \
       g_value_set_##type (&values[i], v[i]); \
     } \
   } \
   g_free (v); \
 }

 /**
  * gst_control_binding_get_g_value_array:
  * @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 length=n_values): array to put control-values in
  *
  * 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.
  *
  * Returns: %TRUE if the given array could be filled, %FALSE otherwise
  */
 gboolean
 gst_control_binding_get_g_value_array (GstControlBinding * binding,
     GstClockTime timestamp, GstClockTime interval, guint n_values,
     GValue * values)
 {
   GstControlBindingClass *klass;
   gboolean ret = FALSE;

   g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
   g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
   g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
   g_return_val_if_fail (values, FALSE);

   klass = GST_CONTROL_BINDING_GET_CLASS (binding);

   if (G_LIKELY (klass->get_g_value_array != NULL)) {
     ret =
         klass->get_g_value_array (binding, timestamp, interval, n_values,
         values);
   } else {
     guint i;
     GType type, base;

     base = type = G_PARAM_SPEC_VALUE_TYPE (GST_CONTROL_BINDING_PSPEC (binding));
     while ((type = g_type_parent (type)))
       base = type;

     GST_INFO_OBJECT (binding, "missing get_g_value_array implementation, we're "
         "emulating it");
     switch (base) {
       case G_TYPE_INT:
         CONVERT_ARRAY (int, INT);
         break;
       case G_TYPE_UINT:
         CONVERT_ARRAY (uint, UINT);
         break;
       case G_TYPE_LONG:
         CONVERT_ARRAY (long, LONG);
         break;
       case G_TYPE_ULONG:
         CONVERT_ARRAY (ulong, ULONG);
         break;
       case G_TYPE_INT64:
         CONVERT_ARRAY (int64, INT64);
         break;
       case G_TYPE_UINT64:
         CONVERT_ARRAY (uint64, UINT64);
         break;
       case G_TYPE_FLOAT:
         CONVERT_ARRAY (float, FLOAT);
         break;
       case G_TYPE_DOUBLE:
         CONVERT_ARRAY (double, DOUBLE);
         break;
       case G_TYPE_BOOLEAN:
         CONVERT_ARRAY (boolean, BOOLEAN);
         break;
       case G_TYPE_ENUM:
       {
         gint *v = g_new (gint, n_values);
         ret = gst_control_binding_get_value_array (binding, timestamp, interval,
             n_values, v);
         if (ret) {
           for (i = 0; i < n_values; i++) {
             g_value_init (&values[i], type);
             g_value_set_enum (&values[i], v[i]);
           }
         }
         g_free (v);
       }
         break;
       default:
         GST_WARNING ("incomplete implementation for paramspec type '%s'",
             G_PARAM_SPEC_TYPE_NAME (GST_CONTROL_BINDING_PSPEC (binding)));
         GST_CONTROL_BINDING_PSPEC (binding) = NULL;
         break;
     }
   }
   return ret;
 }

 /**
  * gst_control_binding_set_disabled:
  * @binding: the control binding
  * @disabled: boolean that specifies whether to disable the controller
  * or not.
  *
  * This function is used to disable a control binding for some time, i.e.
  * gst_object_sync_values() will do nothing.
  */
 void
 gst_control_binding_set_disabled (GstControlBinding * binding,
     gboolean disabled)
 {
   g_return_if_fail (GST_IS_CONTROL_BINDING (binding));
   binding->disabled = disabled;
 }

 /**
  * gst_control_binding_is_disabled:
  * @binding: the control binding
  *
  * Check if the control binding is disabled.
  *
  * Returns: %TRUE if the binding is inactive
  */
 gboolean
 gst_control_binding_is_disabled (GstControlBinding * binding)
 {
   g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), TRUE);
   return ! !binding->disabled;
 }
	/* GStreamer
	*
	* Copyright (C) 2011 Stefan Sauer <ensonic@users.sf.net>
	*
	* gstcontrolbinding.c: Attachment for control sources
	*
	* 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., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/
	/**
	* SECTION:gstcontrolbinding
	* @short_description: attachment for control source sources
	*
	* 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.
	*/
	/* FIXME(ensonic): should we make gst_object_add_control_binding() internal
	* - we create the control_binding for a certain object anyway
	* - we could call gst_object_add_control_binding() at the end of
	* gst_control_binding_constructor()
	* - the weak-ref on object is not nice, as is the same as gst_object_parent()
	* once the object is added to the parent
	*
	* - another option would be to defer what is done in _constructor to when
	* the parent is set (need to listen to the signal then)
	* then basically I could
	* a) remove the obj arg and wait the binding to be added or
	* b) add the binding from constructor, unref object there and make obj
	* writeonly
	*/

	#include "gst_private.h"

	#include <glib-object.h>
	#include <gst/gst.h>

	#include "gstcontrolbinding.h"

	#include <math.h>

	#define GST_CAT_DEFAULT control_binding_debug
	GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

	#define _do_init \
	GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "gstcontrolbinding", 0, \
	"dynamic parameter control source attachment");

	static GObject *gst_control_binding_constructor (GType type,
	guint n_construct_params, GObjectConstructParam * construct_params);
	static void gst_control_binding_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec);
	static void gst_control_binding_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec);
	static void gst_control_binding_dispose (GObject * object);
	static void gst_control_binding_finalize (GObject * object);

	G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstControlBinding, gst_control_binding,
	GST_TYPE_OBJECT, _do_init);

	enum
	{
	PROP_0,
	PROP_OBJECT,
	PROP_NAME,
	PROP_LAST
	};

	static GParamSpec *properties[PROP_LAST];

	static void
	gst_control_binding_class_init (GstControlBindingClass * klass)
	{
	GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

	gobject_class->constructor = gst_control_binding_constructor;
	gobject_class->set_property = gst_control_binding_set_property;
	gobject_class->get_property = gst_control_binding_get_property;
	gobject_class->dispose = gst_control_binding_dispose;
	gobject_class->finalize = gst_control_binding_finalize;

	properties[PROP_OBJECT] =
	g_param_spec_object ("object", "Object",
	"The object of the property", GST_TYPE_OBJECT,
	G_PARAM_READWRITE \| G_PARAM_CONSTRUCT_ONLY \| G_PARAM_STATIC_STRINGS);

	properties[PROP_NAME] =
	g_param_spec_string ("name", "Name", "The name of the property", NULL,
	G_PARAM_READWRITE \| G_PARAM_CONSTRUCT_ONLY \| G_PARAM_STATIC_STRINGS);


	g_object_class_install_properties (gobject_class, PROP_LAST, properties);
	}

	static void
	gst_control_binding_init (GstControlBinding * binding)
	{
	}

	static GObject *
	gst_control_binding_constructor (GType type, guint n_construct_params,
	GObjectConstructParam * construct_params)
	{
	GstControlBinding *binding;
	GParamSpec *pspec;

	binding =
	GST_CONTROL_BINDING (G_OBJECT_CLASS (gst_control_binding_parent_class)
	->constructor (type, n_construct_params, construct_params));

	GST_INFO_OBJECT (binding->object, "trying to put property '%s' under control",
	binding->name);

	/* check if the object has a property of that name */
	if ((pspec =
	g_object_class_find_property (G_OBJECT_GET_CLASS (binding->object),
	binding->name))) {
	GST_DEBUG_OBJECT (binding->object, " psec->flags : 0x%08x", pspec->flags);

	/* check if this param is witable && controlable && !construct-only */
	if ((pspec->flags & (G_PARAM_WRITABLE \| GST_PARAM_CONTROLLABLE \|
	G_PARAM_CONSTRUCT_ONLY)) ==
	(G_PARAM_WRITABLE \| GST_PARAM_CONTROLLABLE)) {
	binding->pspec = pspec;
	} else {
	GST_WARNING_OBJECT (binding->object,
	"property '%s' on class '%s' needs to "
	"be writeable, controlable and not construct_only", binding->name,
	G_OBJECT_TYPE_NAME (binding->object));
	}
	} else {
	GST_WARNING_OBJECT (binding->object, "class '%s' has no property '%s'",
	G_OBJECT_TYPE_NAME (binding->object), binding->name);
	}
	return (GObject *) binding;
	}

	static void
	gst_control_binding_dispose (GObject * object)
	{
	GstControlBinding *self = GST_CONTROL_BINDING (object);

	/* we did not took a reference */
	g_object_remove_weak_pointer ((GObject *) self->object,
	(gpointer *) & self->object);
	self->object = NULL;

	((GObjectClass *) gst_control_binding_parent_class)->dispose (object);
	}

	static void
	gst_control_binding_finalize (GObject * object)
	{
	GstControlBinding *self = GST_CONTROL_BINDING (object);

	g_free (self->name);

	((GObjectClass *) gst_control_binding_parent_class)->finalize (object);
	}

	static void
	gst_control_binding_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec)
	{
	GstControlBinding *self = GST_CONTROL_BINDING (object);

	switch (prop_id) {
	case PROP_OBJECT:
	/* do not ref to avoid a ref cycle */
	self->object = g_value_get_object (value);
	g_object_add_weak_pointer ((GObject *) self->object,
	(gpointer *) & self->object);
	break;
	case PROP_NAME:
	self->name = g_value_dup_string (value);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static void
	gst_control_binding_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec)
	{
	GstControlBinding *self = GST_CONTROL_BINDING (object);

	switch (prop_id) {
	case PROP_OBJECT:
	g_value_set_object (value, self->object);
	break;
	case PROP_NAME:
	g_value_set_string (value, self->name);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	/* functions */

	/**
	* gst_control_binding_sync_values:
	* @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
	*
	* 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.
	*
	* Returns: %TRUE if the controller value could be applied to the object
	* property, %FALSE otherwise
	*/
	gboolean
	gst_control_binding_sync_values (GstControlBinding * binding,
	GstObject * object, GstClockTime timestamp, GstClockTime last_sync)
	{
	GstControlBindingClass *klass;
	gboolean ret = FALSE;

	g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);

	if (binding->disabled)
	return TRUE;

	klass = GST_CONTROL_BINDING_GET_CLASS (binding);

	if (G_LIKELY (klass->sync_values != NULL)) {
	ret = klass->sync_values (binding, object, timestamp, last_sync);
	} else {
	GST_WARNING_OBJECT (binding, "missing sync_values implementation");
	}
	return ret;
	}

	/**
	* gst_control_binding_get_value:
	* @binding: the control binding
	* @timestamp: the time the control-change should be read from
	*
	* Gets the value for the given controlled property at the requested time.
	*
	* Returns: (nullable): the GValue of the property at the given time,
	* or %NULL if the property isn't controlled.
	*/
	GValue *
	gst_control_binding_get_value (GstControlBinding * binding,
	GstClockTime timestamp)
	{
	GstControlBindingClass *klass;
	GValue *ret = NULL;

	g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), NULL);
	g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);

	klass = GST_CONTROL_BINDING_GET_CLASS (binding);

	if (G_LIKELY (klass->get_value != NULL)) {
	ret = klass->get_value (binding, timestamp);
	} else {
	GST_WARNING_OBJECT (binding, "missing get_value implementation");
	}
	return ret;
	}

	/**
	* gst_control_binding_get_value_array: (skip)
	* @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 length=n_values): array to put control-values in
	*
	* 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.
	*
	* Returns: %TRUE if the given array could be filled, %FALSE otherwise
	*/
	gboolean
	gst_control_binding_get_value_array (GstControlBinding * binding,
	GstClockTime timestamp, GstClockTime interval, guint n_values,
	gpointer values)
	{
	GstControlBindingClass *klass;
	gboolean ret = FALSE;

	g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
	g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
	g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
	g_return_val_if_fail (values, FALSE);

	klass = GST_CONTROL_BINDING_GET_CLASS (binding);

	if (G_LIKELY (klass->get_value_array != NULL)) {
	ret =
	klass->get_value_array (binding, timestamp, interval, n_values, values);
	} else {
	GST_WARNING_OBJECT (binding, "missing get_value_array implementation");
	}
	return ret;
	}

	#define CONVERT_ARRAY(type,TYPE) \
	{ \
	g##type *v = g_new (g##type,n_values); \
	ret = gst_control_binding_get_value_array (binding, timestamp, interval, \
	n_values, v); \
	if (ret) { \
	for (i = 0; i < n_values; i++) { \
	g_value_init (&values[i], G_TYPE_##TYPE); \
	g_value_set_##type (&values[i], v[i]); \
	} \
	} \
	g_free (v); \
	}

	/**
	* gst_control_binding_get_g_value_array:
	* @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 length=n_values): array to put control-values in
	*
	* 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.
	*
	* Returns: %TRUE if the given array could be filled, %FALSE otherwise
	*/
	gboolean
	gst_control_binding_get_g_value_array (GstControlBinding * binding,
	GstClockTime timestamp, GstClockTime interval, guint n_values,
	GValue * values)
	{
	GstControlBindingClass *klass;
	gboolean ret = FALSE;

	g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
	g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
	g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
	g_return_val_if_fail (values, FALSE);

	klass = GST_CONTROL_BINDING_GET_CLASS (binding);

	if (G_LIKELY (klass->get_g_value_array != NULL)) {
	ret =
	klass->get_g_value_array (binding, timestamp, interval, n_values,
	values);
	} else {
	guint i;
	GType type, base;

	base = type = G_PARAM_SPEC_VALUE_TYPE (GST_CONTROL_BINDING_PSPEC (binding));
	while ((type = g_type_parent (type)))
	base = type;

	GST_INFO_OBJECT (binding, "missing get_g_value_array implementation, we're "
	"emulating it");
	switch (base) {
	case G_TYPE_INT:
	CONVERT_ARRAY (int, INT);
	break;
	case G_TYPE_UINT:
	CONVERT_ARRAY (uint, UINT);
	break;
	case G_TYPE_LONG:
	CONVERT_ARRAY (long, LONG);
	break;
	case G_TYPE_ULONG:
	CONVERT_ARRAY (ulong, ULONG);
	break;
	case G_TYPE_INT64:
	CONVERT_ARRAY (int64, INT64);
	break;
	case G_TYPE_UINT64:
	CONVERT_ARRAY (uint64, UINT64);
	break;
	case G_TYPE_FLOAT:
	CONVERT_ARRAY (float, FLOAT);
	break;
	case G_TYPE_DOUBLE:
	CONVERT_ARRAY (double, DOUBLE);
	break;
	case G_TYPE_BOOLEAN:
	CONVERT_ARRAY (boolean, BOOLEAN);
	break;
	case G_TYPE_ENUM:
	{
	gint *v = g_new (gint, n_values);
	ret = gst_control_binding_get_value_array (binding, timestamp, interval,
	n_values, v);
	if (ret) {
	for (i = 0; i < n_values; i++) {
	g_value_init (&values[i], type);
	g_value_set_enum (&values[i], v[i]);
	}
	}
	g_free (v);
	}
	break;
	default:
	GST_WARNING ("incomplete implementation for paramspec type '%s'",
	G_PARAM_SPEC_TYPE_NAME (GST_CONTROL_BINDING_PSPEC (binding)));
	GST_CONTROL_BINDING_PSPEC (binding) = NULL;
	break;
	}
	}
	return ret;
	}

	/**
	* gst_control_binding_set_disabled:
	* @binding: the control binding
	* @disabled: boolean that specifies whether to disable the controller
	* or not.
	*
	* This function is used to disable a control binding for some time, i.e.
	* gst_object_sync_values() will do nothing.
	*/
	void
	gst_control_binding_set_disabled (GstControlBinding * binding,
	gboolean disabled)
	{
	g_return_if_fail (GST_IS_CONTROL_BINDING (binding));
	binding->disabled = disabled;
	}

	/**
	* gst_control_binding_is_disabled:
	* @binding: the control binding
	*
	* Check if the control binding is disabled.
	*
	* Returns: %TRUE if the binding is inactive
	*/
	gboolean
	gst_control_binding_is_disabled (GstControlBinding * binding)
	{
	g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), TRUE);
	return ! !binding->disabled;
	}