| /* GStreamer |
| * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de> |
| * |
| * gsttypefind.c: typefinding subsystem |
| * |
| * 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., 59 Temple Place - Suite 330, |
| * Boston, MA 02111-1307, USA. |
| */ |
| |
| /** |
| * SECTION:gsttypefind |
| * @short_description: Stream type detection |
| * |
| * The following functions allow you to detect the media type of an unknown |
| * stream. |
| * |
| * Last reviewed on 2005-11-09 (0.9.4) |
| */ |
| |
| #include "gst_private.h" |
| #include "gstinfo.h" |
| #include "gsttypefind.h" |
| #include "gstregistry.h" |
| #include "gsttypefindfactory.h" |
| |
| GST_DEBUG_CATEGORY_EXTERN (type_find_debug); |
| #define GST_CAT_DEFAULT type_find_debug |
| |
| GType |
| gst_type_find_get_type (void) |
| { |
| static GType typefind_type = 0; |
| |
| if (G_UNLIKELY (typefind_type == 0)) { |
| typefind_type = g_pointer_type_register_static ("GstTypeFind"); |
| } |
| return typefind_type; |
| } |
| |
| /** |
| * gst_type_find_register: |
| * @plugin: A #GstPlugin, or NULL for a static typefind function (note that |
| * passing NULL only works in GStreamer 0.10.16 and later) |
| * @name: The name for registering |
| * @rank: The rank (or importance) of this typefind function |
| * @func: The #GstTypeFindFunction to use |
| * @extensions: (transfer none) (array zero-terminated=1) (element-type utf8): |
| * Optional extensions that could belong to this type |
| * @possible_caps: Optionally the caps that could be returned when typefinding |
| * succeeds |
| * @data: Optional user data. This user data must be available until the plugin |
| * is unloaded. |
| * @data_notify: a #GDestroyNotify that will be called on @data when the plugin |
| * is unloaded. |
| * |
| * Registers a new typefind function to be used for typefinding. After |
| * registering this function will be available for typefinding. |
| * This function is typically called during an element's plugin initialization. |
| * |
| * Returns: TRUE on success, FALSE otherwise |
| */ |
| gboolean |
| gst_type_find_register (GstPlugin * plugin, const gchar * name, guint rank, |
| GstTypeFindFunction func, gchar ** extensions, |
| const GstCaps * possible_caps, gpointer data, GDestroyNotify data_notify) |
| { |
| GstTypeFindFactory *factory; |
| |
| g_return_val_if_fail (name != NULL, FALSE); |
| |
| GST_INFO ("registering typefind function for %s", name); |
| |
| factory = g_object_newv (GST_TYPE_TYPE_FIND_FACTORY, 0, NULL); |
| GST_DEBUG_OBJECT (factory, "using new typefind factory for %s", name); |
| g_assert (GST_IS_TYPE_FIND_FACTORY (factory)); |
| |
| gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name); |
| gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank); |
| |
| if (factory->extensions) |
| g_strfreev (factory->extensions); |
| factory->extensions = g_strdupv (extensions); |
| |
| gst_caps_replace (&factory->caps, (GstCaps *) possible_caps); |
| factory->function = func; |
| factory->user_data = data; |
| factory->user_data_notify = data_notify; |
| if (plugin && plugin->desc.name) { |
| GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name; /* interned string */ |
| GST_PLUGIN_FEATURE_CAST (factory)->plugin = plugin; |
| g_object_add_weak_pointer ((GObject *) plugin, |
| (gpointer *) & GST_PLUGIN_FEATURE_CAST (factory)->plugin); |
| } else { |
| GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL"; |
| GST_PLUGIN_FEATURE_CAST (factory)->plugin = NULL; |
| } |
| GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE; |
| |
| gst_registry_add_feature (gst_registry_get_default (), |
| GST_PLUGIN_FEATURE_CAST (factory)); |
| |
| return TRUE; |
| } |
| |
| /*** typefind function interface **********************************************/ |
| |
| /** |
| * gst_type_find_peek: |
| * @find: The #GstTypeFind object the function was called with |
| * @offset: The offset |
| * @size: The number of bytes to return |
| * |
| * Returns the @size bytes of the stream to identify beginning at offset. If |
| * offset is a positive number, the offset is relative to the beginning of the |
| * stream, if offset is a negative number the offset is relative to the end of |
| * the stream. The returned memory is valid until the typefinding function |
| * returns and must not be freed. |
| * |
| * Returns: (transfer none) (array length=size): the requested data, or NULL |
| * if that data is not available. |
| */ |
| const guint8 * |
| gst_type_find_peek (GstTypeFind * find, gint64 offset, guint size) |
| { |
| g_return_val_if_fail (find->peek != NULL, NULL); |
| |
| return find->peek (find->data, offset, size); |
| } |
| |
| /** |
| * gst_type_find_suggest: |
| * @find: The #GstTypeFind object the function was called with |
| * @probability: The probability in percent that the suggestion is right |
| * @caps: The fixed #GstCaps to suggest |
| * |
| * If a #GstTypeFindFunction calls this function it suggests the caps with the |
| * given probability. A #GstTypeFindFunction may supply different suggestions |
| * in one call. |
| * It is up to the caller of the #GstTypeFindFunction to interpret these values. |
| */ |
| void |
| gst_type_find_suggest (GstTypeFind * find, guint probability, |
| const GstCaps * caps) |
| { |
| g_return_if_fail (find->suggest != NULL); |
| g_return_if_fail (probability <= 100); |
| g_return_if_fail (caps != NULL); |
| g_return_if_fail (gst_caps_is_fixed (caps)); |
| |
| find->suggest (find->data, probability, caps); |
| } |
| |
| /** |
| * gst_type_find_suggest_simple: |
| * @find: The #GstTypeFind object the function was called with |
| * @probability: The probability in percent that the suggestion is right |
| * @media_type: the media type of the suggested caps |
| * @fieldname: first field of the suggested caps, or NULL |
| * @...: additional arguments to the suggested caps in the same format as the |
| * arguments passed to gst_structure_new() (ie. triplets of field name, |
| * field GType and field value) |
| * |
| * If a #GstTypeFindFunction calls this function it suggests the caps with the |
| * given probability. A #GstTypeFindFunction may supply different suggestions |
| * in one call. It is up to the caller of the #GstTypeFindFunction to interpret |
| * these values. |
| * |
| * This function is similar to gst_type_find_suggest(), only that instead of |
| * passing a #GstCaps argument you can create the caps on the fly in the same |
| * way as you can with gst_caps_new_simple(). |
| * |
| * Make sure you terminate the list of arguments with a NULL argument and that |
| * the values passed have the correct type (in terms of width in bytes when |
| * passed to the vararg function - this applies particularly to gdouble and |
| * guint64 arguments). |
| * |
| * Since: 0.10.20 |
| */ |
| void |
| gst_type_find_suggest_simple (GstTypeFind * find, guint probability, |
| const char *media_type, const char *fieldname, ...) |
| { |
| GstStructure *structure; |
| va_list var_args; |
| GstCaps *caps; |
| |
| g_return_if_fail (find->suggest != NULL); |
| g_return_if_fail (probability <= 100); |
| g_return_if_fail (media_type != NULL); |
| |
| caps = gst_caps_new_empty (); |
| |
| va_start (var_args, fieldname); |
| structure = gst_structure_new_valist (media_type, fieldname, var_args); |
| va_end (var_args); |
| |
| gst_caps_append_structure (caps, structure); |
| g_return_if_fail (gst_caps_is_fixed (caps)); |
| |
| find->suggest (find->data, probability, caps); |
| gst_caps_unref (caps); |
| } |
| |
| /** |
| * gst_type_find_get_length: |
| * @find: The #GstTypeFind the function was called with |
| * |
| * Get the length of the data stream. |
| * |
| * Returns: The length of the data stream, or 0 if it is not available. |
| */ |
| guint64 |
| gst_type_find_get_length (GstTypeFind * find) |
| { |
| if (find->get_length == NULL) |
| return 0; |
| |
| return find->get_length (find->data); |
| } |