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223 lines
6.5 KiB
C
223 lines
6.5 KiB
C
/* GStreamer
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* Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
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*
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* gsttypefindfactory.c: typefinding subsystem
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/**
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* SECTION:gsttypefindfactory
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* @short_description: Information about registered typefind functions
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*
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* These functions allow querying informations about registered typefind
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* functions. How to create and register these functions is described in
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* the section <link linkend="gstreamer-Writing-typefind-functions">
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* "Writing typefind functions"</link>.
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*
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* <example>
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* <title>how to write a simple typefinder</title>
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* <programlisting>
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* typedef struct {
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* guint8 *data;
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* guint size;
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* guint probability;
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* GstCaps *data;
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* } MyTypeFind;
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* static void
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* my_peek (gpointer data, gint64 offset, guint size)
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* {
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* MyTypeFind *find = (MyTypeFind *) data;
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* if (offset >= 0 && offset + size <= find->size) {
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* return find->data + offset;
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* }
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* return NULL;
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* }
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* static void
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* my_suggest (gpointer data, guint probability, GstCaps *caps)
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* {
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* MyTypeFind *find = (MyTypeFind *) data;
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* if (probability > find->probability) {
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* find->probability = probability;
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* gst_caps_replace (&find->caps, caps);
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* }
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* }
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* static GstCaps *
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* find_type (guint8 *data, guint size)
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* {
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* GList *walk, *type_list;
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* MyTypeFind find = {data, size, 0, NULL};
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* GstTypeFind gst_find = {my_peek, my_suggest, &find, };
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* walk = type_list = gst_type_find_factory_get_list ();
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* while (walk) {
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* GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (walk->data);
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* walk = g_list_next (walk)
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* gst_type_find_factory_call_function (factory, &gst_find);
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* }
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* g_list_free (type_list);
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* return find.caps;
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* };
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* </programlisting>
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* </example>
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*
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* The above example shows how to write a very simple typefinder that
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* identifies the given data. You can get quite a bit more complicated than
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* that though.
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*
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* Last reviewed on 2005-11-09 (0.9.4)
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*/
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#include "gst_private.h"
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#include "gstinfo.h"
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#include "gsttypefind.h"
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#include "gsttypefindfactory.h"
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#include "gstregistry.h"
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GST_DEBUG_CATEGORY (type_find_debug);
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#define GST_CAT_DEFAULT type_find_debug
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static void gst_type_find_factory_dispose (GObject * object);
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static GstPluginFeatureClass *parent_class = NULL;
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#define _do_init \
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{ \
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GST_DEBUG_CATEGORY_INIT (type_find_debug, "GST_TYPEFIND", \
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GST_DEBUG_FG_GREEN, "typefinding subsystem"); \
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}
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G_DEFINE_TYPE_WITH_CODE (GstTypeFindFactory, gst_type_find_factory,
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GST_TYPE_PLUGIN_FEATURE, _do_init);
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static void
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gst_type_find_factory_class_init (GstTypeFindFactoryClass * klass)
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{
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GObjectClass *object_class = G_OBJECT_CLASS (klass);
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parent_class = g_type_class_peek_parent (klass);
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object_class->dispose = gst_type_find_factory_dispose;
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}
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static void
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gst_type_find_factory_init (GstTypeFindFactory * factory)
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{
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factory->user_data = factory;
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factory->user_data_notify = NULL;
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}
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static void
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gst_type_find_factory_dispose (GObject * object)
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{
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GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (object);
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if (factory->caps) {
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gst_caps_unref (factory->caps);
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factory->caps = NULL;
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}
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if (factory->extensions) {
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g_strfreev (factory->extensions);
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factory->extensions = NULL;
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}
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if (factory->user_data_notify && factory->user_data) {
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factory->user_data_notify (factory->user_data);
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factory->user_data = NULL;
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}
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G_OBJECT_CLASS (parent_class)->dispose (object);
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}
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/**
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* gst_type_find_factory_get_list:
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*
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* Gets the list of all registered typefind factories. You must free the
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* list using gst_plugin_feature_list_free.
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*
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* The returned factories are sorted by highest rank first, and then by
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* factory name. (behaviour change since 0.10.26)
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*
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* Returns: the list of all registered #GstTypeFindFactory.
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*/
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GList *
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gst_type_find_factory_get_list (void)
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{
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return gst_registry_get_feature_list (gst_registry_get_default (),
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GST_TYPE_TYPE_FIND_FACTORY);
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}
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/**
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* gst_type_find_factory_get_caps:
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* @factory: A #GstTypeFindFactory
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*
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* Gets the #GstCaps associated with a typefind factory.
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*
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* Returns: The #GstCaps associated with this factory
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*/
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GstCaps *
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gst_type_find_factory_get_caps (GstTypeFindFactory * factory)
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{
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g_return_val_if_fail (GST_IS_TYPE_FIND_FACTORY (factory), NULL);
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return factory->caps;
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}
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/**
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* gst_type_find_factory_get_extensions:
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* @factory: A #GstTypeFindFactory
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*
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* Gets the extensions associated with a #GstTypeFindFactory. The returned
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* array should not be changed. If you need to change stuff in it, you should
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* copy it using g_strdupv(). This function may return NULL to indicate
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* a 0-length list.
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*
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* Returns: a NULL-terminated array of extensions associated with this factory
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*/
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gchar **
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gst_type_find_factory_get_extensions (GstTypeFindFactory * factory)
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{
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g_return_val_if_fail (GST_IS_TYPE_FIND_FACTORY (factory), NULL);
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return factory->extensions;
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}
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/**
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* gst_type_find_factory_call_function:
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* @factory: A #GstTypeFindFactory
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* @find: A properly setup #GstTypeFind entry. The get_data and suggest_type
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* members must be set.
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*
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* Calls the #GstTypeFindFunction associated with this factory.
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*/
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void
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gst_type_find_factory_call_function (GstTypeFindFactory * factory,
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GstTypeFind * find)
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{
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GstTypeFindFactory *new_factory;
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g_return_if_fail (GST_IS_TYPE_FIND_FACTORY (factory));
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g_return_if_fail (find != NULL);
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g_return_if_fail (find->peek != NULL);
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g_return_if_fail (find->suggest != NULL);
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new_factory =
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GST_TYPE_FIND_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
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(factory)));
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if (new_factory) {
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if (new_factory->function)
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new_factory->function (find, new_factory->user_data);
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gst_object_unref (new_factory);
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}
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}
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