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225 lines
7.5 KiB
C
225 lines
7.5 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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* gsttypefind.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:gsttypefind
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* @short_description: Stream type detection
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*
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* The following functions allow you to detect the media type of an unknown
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* stream.
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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 "gstregistry.h"
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#include "gsttypefindfactory.h"
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GST_DEBUG_CATEGORY_EXTERN (type_find_debug);
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#define GST_CAT_DEFAULT type_find_debug
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GType
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gst_type_find_get_type (void)
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{
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static GType typefind_type = 0;
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if (G_UNLIKELY (typefind_type == 0)) {
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typefind_type = g_pointer_type_register_static ("GstTypeFind");
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}
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return typefind_type;
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}
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/**
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* gst_type_find_register:
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* @plugin: A #GstPlugin, or NULL for a static typefind function (note that
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* passing NULL only works in GStreamer 0.10.16 and later)
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* @name: The name for registering
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* @rank: The rank (or importance) of this typefind function
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* @func: The #GstTypeFindFunction to use
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* @extensions: Optional extensions that could belong to this type
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* @possible_caps: Optionally the caps that could be returned when typefinding
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* succeeds
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* @data: Optional user data. This user data must be available until the plugin
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* is unloaded.
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* @data_notify: a #GDestroyNotify that will be called on @data when the plugin
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* is unloaded.
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*
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* Registers a new typefind function to be used for typefinding. After
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* registering this function will be available for typefinding.
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* This function is typically called during an element's plugin initialization.
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*
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* Returns: TRUE on success, FALSE otherwise
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*/
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gboolean
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gst_type_find_register (GstPlugin * plugin, const gchar * name, guint rank,
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GstTypeFindFunction func, gchar ** extensions,
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const GstCaps * possible_caps, gpointer data, GDestroyNotify data_notify)
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{
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GstTypeFindFactory *factory;
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g_return_val_if_fail (name != NULL, FALSE);
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GST_INFO ("registering typefind function for %s", name);
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factory = g_object_new (GST_TYPE_TYPE_FIND_FACTORY, NULL);
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GST_DEBUG_OBJECT (factory, "using new typefind factory for %s", name);
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g_assert (GST_IS_TYPE_FIND_FACTORY (factory));
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gst_plugin_feature_set_name (GST_PLUGIN_FEATURE (factory), name);
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gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE (factory), rank);
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if (factory->extensions)
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g_strfreev (factory->extensions);
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factory->extensions = g_strdupv (extensions);
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gst_caps_replace (&factory->caps, (GstCaps *) possible_caps);
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factory->function = func;
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factory->user_data = data;
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factory->user_data_notify = data_notify;
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if (plugin && plugin->desc.name) {
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GST_PLUGIN_FEATURE (factory)->plugin_name = plugin->desc.name; /* interned string */
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} else {
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GST_PLUGIN_FEATURE (factory)->plugin_name = "NULL";
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}
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GST_PLUGIN_FEATURE (factory)->loaded = TRUE;
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gst_registry_add_feature (gst_registry_get_default (),
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GST_PLUGIN_FEATURE (factory));
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return TRUE;
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}
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/*** typefind function interface **********************************************/
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/**
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* gst_type_find_peek:
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* @find: The #GstTypeFind object the function was called with
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* @offset: The offset
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* @size: The number of bytes to return
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*
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* Returns the @size bytes of the stream to identify beginning at offset. If
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* offset is a positive number, the offset is relative to the beginning of the
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* stream, if offset is a negative number the offset is relative to the end of
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* the stream. The returned memory is valid until the typefinding function
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* returns and must not be freed.
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*
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* Returns: the requested data, or NULL if that data is not available.
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*/
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guint8 *
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gst_type_find_peek (GstTypeFind * find, gint64 offset, guint size)
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{
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g_return_val_if_fail (find->peek != NULL, NULL);
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return find->peek (find->data, offset, size);
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}
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/**
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* gst_type_find_suggest:
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* @find: The #GstTypeFind object the function was called with
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* @probability: The probability in percent that the suggestion is right
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* @caps: The fixed #GstCaps to suggest
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*
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* If a #GstTypeFindFunction calls this function it suggests the caps with the
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* given probability. A #GstTypeFindFunction may supply different suggestions
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* in one call.
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* It is up to the caller of the #GstTypeFindFunction to interpret these values.
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*/
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void
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gst_type_find_suggest (GstTypeFind * find, guint probability,
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const GstCaps * caps)
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{
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g_return_if_fail (find->suggest != NULL);
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g_return_if_fail (probability <= 100);
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g_return_if_fail (caps != NULL);
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g_return_if_fail (gst_caps_is_fixed (caps));
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find->suggest (find->data, probability, caps);
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}
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/**
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* gst_type_find_suggest_simple:
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* @find: The #GstTypeFind object the function was called with
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* @probability: The probability in percent that the suggestion is right
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* @media_type: the media type of the suggested caps
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* @fieldname: first field of the suggested caps, or NULL
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* @...: additional arguments to the suggested caps in the same format as the
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* arguments passed to gst_structure_new() (ie. triplets of field name,
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* field GType and field value)
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*
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* If a #GstTypeFindFunction calls this function it suggests the caps with the
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* given probability. A #GstTypeFindFunction may supply different suggestions
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* in one call. It is up to the caller of the #GstTypeFindFunction to interpret
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* these values.
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*
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* This function is similar to gst_type_find_suggest(), only that instead of
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* passing a #GstCaps argument you can create the caps on the fly in the same
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* way as you can with gst_caps_new_simple().
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*
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* Make sure you terminate the list of arguments with a NULL argument and that
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* the values passed have the correct type (in terms of width in bytes when
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* passed to the vararg function - this applies particularly to gdouble and
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* guint64 arguments).
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*
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* Since: 0.10.20
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*/
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void
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gst_type_find_suggest_simple (GstTypeFind * find, guint probability,
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const char *media_type, const char *fieldname, ...)
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{
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GstStructure *structure;
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va_list var_args;
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GstCaps *caps;
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g_return_if_fail (find->suggest != NULL);
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g_return_if_fail (probability <= 100);
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g_return_if_fail (media_type != NULL);
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caps = gst_caps_new_empty ();
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va_start (var_args, fieldname);
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structure = gst_structure_new_valist (media_type, fieldname, var_args);
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va_end (var_args);
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gst_caps_append_structure (caps, structure);
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g_return_if_fail (gst_caps_is_fixed (caps));
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find->suggest (find->data, probability, caps);
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gst_caps_unref (caps);
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}
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/**
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* gst_type_find_get_length:
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* @find: The #GstTypeFind the function was called with
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*
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* Get the length of the data stream.
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*
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* Returns: The length of the data stream, or 0 if it is not available.
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*/
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guint64
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gst_type_find_get_length (GstTypeFind * find)
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{
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if (find->get_length == NULL)
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return 0;
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return find->get_length (find->data);
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}
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