GstElementFactory

GstElementFactory — Create GstElements from a factory

Synopsis


#include <gst/gst.h>

                    GstElementFactory;
                    GstElementDetails;
#define             GST_ELEMENT_DETAILS                 (longname,klass,description,author)
#define             GST_IS_ELEMENT_DETAILS              (details)
gboolean            gst_element_register                (GstPlugin *plugin,
                                                         const gchar *name,
                                                         guint rank,
                                                         GType type);
GstElementFactory*  gst_element_factory_find            (const gchar *name);
GType               gst_element_factory_get_element_type
                                                        (GstElementFactory *factory);
const gchar*        gst_element_factory_get_longname    (GstElementFactory *factory);
const gchar*        gst_element_factory_get_klass       (GstElementFactory *factory);
const gchar*        gst_element_factory_get_description (GstElementFactory *factory);
const gchar*        gst_element_factory_get_author      (GstElementFactory *factory);
guint               gst_element_factory_get_num_pad_templates
                                                        (GstElementFactory *factory);
gint                gst_element_factory_get_uri_type    (GstElementFactory *factory);
gchar**             gst_element_factory_get_uri_protocols
                                                        (GstElementFactory *factory);
gboolean            gst_element_factory_has_interface   (GstElementFactory *factory,
                                                         const gchar *interfacename);
GstElement*         gst_element_factory_create          (GstElementFactory *factory,
                                                         const gchar *name);
GstElement*         gst_element_factory_make            (const gchar *factoryname,
                                                         const gchar *name);
gboolean            gst_element_factory_can_sink_caps   (GstElementFactory *factory,
                                                         const GstCaps *caps);
gboolean            gst_element_factory_can_src_caps    (GstElementFactory *factory,
                                                         const GstCaps *caps);
const GList*        gst_element_factory_get_static_pad_templates
                                                        (GstElementFactory *factory);

Object Hierarchy

  GObject
   +----GstObject
         +----GstPluginFeature
               +----GstElementFactory

Description

GstElementFactory is used to create instances of elements. A GstElementfactory can be added to a GstPlugin as it is also a GstPluginFeature.

Use the gst_element_factory_find() and gst_element_factory_create() functions to create element instances or use gst_element_factory_make() as a convenient shortcut.

The following code example shows you how to create a GstFileSrc element.

Example 9. Using an element factory

  #include <gst/gst.h>

  GstElement *src;
  GstElementFactory *srcfactory;

  gst_init (&argc, &argv);

  srcfactory = gst_element_factory_find ("filesrc");
  g_return_if_fail (srcfactory != NULL);
  src = gst_element_factory_create (srcfactory, "src");
  g_return_if_fail (src != NULL);
  ...


Last reviewed on 2005-11-23 (0.9.5)

Details

GstElementFactory

typedef struct _GstElementFactory GstElementFactory;

The opaque GstElementFactory data structure.

GstElementDetails

typedef struct {
  gchar *longname;
  gchar *klass;
  gchar *description;
  gchar *author;
} GstElementDetails;

This struct defines the public information about a GstElement. It contains meta-data about the element that is mostly for the benefit of editors.

The klass member can be used by applications to filter elements based on functionality.

gchar *longname; long, english name
gchar *klass; string describing the type of element, as an unordered list separated with slashes ('/'). See draft-klass.txt of the design docs for more details and common types
gchar *description; what the element is about
gchar *author; who wrote this thing?

GST_ELEMENT_DETAILS()

#define             GST_ELEMENT_DETAILS(longname,klass,description,author)

Macro to initialize GstElementDetails.

longname : long, english name
klass : string describing the type of element, as an unordered list separated with slashes ('/'). See draft-klass.txt of the design docs for more details and common types
description : what the element is about
author : who wrote this element

GST_IS_ELEMENT_DETAILS()

#define             GST_IS_ELEMENT_DETAILS(details)

Tests if element details are initialized.

details : the GstElementDetails to check

gst_element_register ()

gboolean            gst_element_register                (GstPlugin *plugin,
                                                         const gchar *name,
                                                         guint rank,
                                                         GType type);

Create a new elementfactory capable of instantiating objects of the type and add the factory to plugin.

plugin : GstPlugin to register the element with, or NULL for a static element (note that passing NULL only works in GStreamer 0.10.13 and later)
name : name of elements of this type
rank : rank of element (higher rank means more importance when autoplugging)
type : GType of element to register
Returns : TRUE, if the registering succeeded, FALSE on error

gst_element_factory_find ()

GstElementFactory*  gst_element_factory_find            (const gchar *name);

Search for an element factory of the given name. Refs the returned element factory; caller is responsible for unreffing.

name : name of factory to find
Returns : GstElementFactory if found, NULL otherwise

gst_element_factory_get_element_type ()

GType               gst_element_factory_get_element_type
                                                        (GstElementFactory *factory);

Get the GType for elements managed by this factory. The type can only be retrieved if the element factory is loaded, which can be assured with gst_plugin_feature_load().

factory : factory to get managed GType from
Returns : the GType for elements managed by this factory or 0 if the factory is not loaded.

gst_element_factory_get_longname ()

const gchar*        gst_element_factory_get_longname    (GstElementFactory *factory);

Gets the longname for this factory

factory : a GstElementFactory
Returns : the longname

gst_element_factory_get_klass ()

const gchar*        gst_element_factory_get_klass       (GstElementFactory *factory);

Gets the class for this factory.

factory : a GstElementFactory
Returns : the class

gst_element_factory_get_description ()

const gchar*        gst_element_factory_get_description (GstElementFactory *factory);

Gets the description for this factory.

factory : a GstElementFactory
Returns : the description

gst_element_factory_get_author ()

const gchar*        gst_element_factory_get_author      (GstElementFactory *factory);

Gets the author for this factory.

factory : a GstElementFactory
Returns : the author

gst_element_factory_get_num_pad_templates ()

guint               gst_element_factory_get_num_pad_templates
                                                        (GstElementFactory *factory);

Gets the number of pad_templates in this factory.

factory : a GstElementFactory
Returns : the number of pad_templates

gst_element_factory_get_uri_type ()

gint                gst_element_factory_get_uri_type    (GstElementFactory *factory);

Gets the type of URIs the element supports or GST_URI_UNKNOWN if none.

factory : a GstElementFactory
Returns : type of URIs this element supports

gst_element_factory_get_uri_protocols ()

gchar**             gst_element_factory_get_uri_protocols
                                                        (GstElementFactory *factory);

Gets a NULL-terminated array of protocols this element supports or NULL if no protocols are supported. You may not change the contents of the returned array, as it is still owned by the element factory. Use g_strdupv() to make a copy of the protocol string array if you need to.

factory : a GstElementFactory
Returns : the supported protocols or NULL

gst_element_factory_has_interface ()

gboolean            gst_element_factory_has_interface   (GstElementFactory *factory,
                                                         const gchar *interfacename);

Check if factory implements the interface with name interfacename.

factory : a GstElementFactory
interfacename : an interface name
Returns : TRUE when factory implement the interface.

Since 0.10.14

gst_element_factory_create ()

GstElement*         gst_element_factory_create          (GstElementFactory *factory,
                                                         const gchar *name);

Create a new element of the type defined by the given elementfactory. It will be given the name supplied, since all elements require a name as their first argument.

factory : factory to instantiate
name : name of new element
Returns : new GstElement or NULL if the element couldn't be created

gst_element_factory_make ()

GstElement*         gst_element_factory_make            (const gchar *factoryname,
                                                         const gchar *name);

Create a new element of the type defined by the given element factory. If name is NULL, then the element will receive a guaranteed unique name, consisting of the element factory name and a number. If name is given, it will be given the name supplied.

factoryname : a named factory to instantiate
name : name of new element
Returns : new GstElement or NULL if unable to create element

gst_element_factory_can_sink_caps ()

gboolean            gst_element_factory_can_sink_caps   (GstElementFactory *factory,
                                                         const GstCaps *caps);

Checks if the factory can sink the given capability.

factory : factory to query
caps : the caps to check
Returns : true if it can sink the capabilities

gst_element_factory_can_src_caps ()

gboolean            gst_element_factory_can_src_caps    (GstElementFactory *factory,
                                                         const GstCaps *caps);

Checks if the factory can source the given capability.

factory : factory to query
caps : the caps to check
Returns : true if it can src the capabilities

gst_element_factory_get_static_pad_templates ()

const GList*        gst_element_factory_get_static_pad_templates
                                                        (GstElementFactory *factory);

Gets the GList of GstStaticPadTemplate for this factory.

factory : a GstElementFactory
Returns : the padtemplates

See Also

GstElement, GstPlugin, GstPluginFeature, GstPadTemplate.
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