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166cfadb71
Add support for adding tags to the metadata. with some standard keys, this should make it possible to describe what the metadata refers to. We should be able to use this information to decide if a transformation destroys the metadata or not.
129 lines
3.6 KiB
C
129 lines
3.6 KiB
C
/* GStreamer
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* Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.com>
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*
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* gstmeta.c: metadata operations
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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:gstmeta
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* @short_description: Buffer metadata
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*
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* Last reviewed on December 17th, 2009 (0.10.26)
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*/
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#include "gst_private.h"
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#include "gstbuffer.h"
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#include "gstmeta.h"
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#include "gstinfo.h"
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#include "gstutils.h"
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static GHashTable *metainfo = NULL;
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static GRWLock lock;
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GQuark _gst_meta_transform_copy;
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void
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_priv_gst_meta_initialize (void)
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{
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g_rw_lock_init (&lock);
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metainfo = g_hash_table_new (g_str_hash, g_str_equal);
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_gst_meta_transform_copy = g_quark_from_static_string ("copy");
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}
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/**
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* gst_meta_register:
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* @api: the name of the #GstMeta API
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* @impl: the name of the #GstMeta implementation
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* @size: the size of the #GstMeta structure
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* @init_func: a #GstMetaInitFunction
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* @free_func: a #GstMetaFreeFunction
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* @transform_func: a #GstMetaTransformFunction
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* @tags: a NULL terminated array of strings describing what the metadata
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* contains info about.
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*
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* Register a new #GstMeta implementation.
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*
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* The same @info can be retrieved later with gst_meta_get_info() by using
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* @impl as the key.
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*
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* Returns: (transfer none): a #GstMetaInfo that can be used to access metadata.
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*/
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const GstMetaInfo *
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gst_meta_register (const gchar * api, const gchar * impl, gsize size,
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GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
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GstMetaTransformFunction transform_func, const gchar ** tags)
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{
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GstMetaInfo *info;
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guint len, i;
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GQuark *qtags;
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g_return_val_if_fail (api != NULL, NULL);
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g_return_val_if_fail (impl != NULL, NULL);
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g_return_val_if_fail (size != 0, NULL);
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g_return_val_if_fail (tags != NULL, NULL);
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info = g_slice_new (GstMetaInfo);
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info->api = g_quark_from_string (api);
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info->type = g_pointer_type_register_static (impl);
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info->size = size;
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info->init_func = init_func;
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info->free_func = free_func;
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info->transform_func = transform_func;
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len = g_strv_length ((gchar **) tags);
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qtags = g_new0 (GQuark, len);
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for (i = 0; i < len; i++)
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qtags[i] = g_quark_from_static_string (tags[i]);
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info->tags = qtags;
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GST_DEBUG ("register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
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api, impl, size);
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g_rw_lock_writer_lock (&lock);
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g_hash_table_insert (metainfo, (gpointer) impl, (gpointer) info);
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g_rw_lock_writer_unlock (&lock);
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return info;
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}
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/**
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* gst_meta_get_info:
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* @impl: the name
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*
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* Lookup a previously registered meta info structure by its implementation name
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* @impl.
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*
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* Returns: (transfer none): a #GstMetaInfo with @impl, or #NULL when no such
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* metainfo exists.
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*/
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const GstMetaInfo *
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gst_meta_get_info (const gchar * impl)
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{
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GstMetaInfo *info;
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g_return_val_if_fail (impl != NULL, NULL);
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g_rw_lock_reader_lock (&lock);
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info = g_hash_table_lookup (metainfo, impl);
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g_rw_lock_reader_unlock (&lock);
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return info;
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}
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