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157471889e
``` gstmeta.c:500: Warning: Gst: gst_meta_info_new: return value: Invalid non-constant return of bare structure or union; register as boxed type or (skip) ``` Skip this for now Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6147>
811 lines
22 KiB
C
811 lines
22 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., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:gstmeta
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* @title: GstMeta
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* @short_description: Buffer metadata
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*
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* The #GstMeta structure should be included as the first member of a #GstBuffer
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* metadata structure. The structure defines the API of the metadata and should
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* be accessible to all elements using the metadata.
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*
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* A metadata API is registered with gst_meta_api_type_register() which takes a
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* name for the metadata API and some tags associated with the metadata.
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* With gst_meta_api_type_has_tag() one can check if a certain metadata API
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* contains a given tag.
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*
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* Multiple implementations of a metadata API can be registered.
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* To implement a metadata API, gst_meta_register() should be used. This
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* function takes all parameters needed to create, free and transform metadata
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* along with the size of the metadata. The function returns a #GstMetaInfo
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* structure that contains the information for the implementation of the API.
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*
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* A specific implementation can be retrieved by name with gst_meta_get_info().
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*
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* See #GstBuffer for how the metadata can be added, retrieved and removed from
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* buffers.
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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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#include "gstquark.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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GQuark _gst_meta_tag_memory;
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GQuark _gst_meta_tag_memory_reference;
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typedef struct
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{
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GstMetaInfo info;
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GstCustomMetaTransformFunction custom_transform_func;
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gpointer custom_transform_user_data;
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GDestroyNotify custom_transform_destroy_notify;
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gboolean is_custom;
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} GstMetaInfoImpl;
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static void
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free_info (gpointer data)
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{
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g_free (data);
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}
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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_full (g_str_hash, g_str_equal, NULL, free_info);
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_gst_meta_transform_copy = g_quark_from_static_string ("gst-copy");
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_gst_meta_tag_memory = g_quark_from_static_string ("memory");
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_gst_meta_tag_memory_reference =
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g_quark_from_static_string ("memory-reference");
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}
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static gboolean
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notify_custom (gchar * key, GstMetaInfo * info, gpointer unused)
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{
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GstMetaInfoImpl *impl = (GstMetaInfoImpl *) info;
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if (impl->is_custom) {
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if (impl->custom_transform_destroy_notify)
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impl->custom_transform_destroy_notify (impl->custom_transform_user_data);
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}
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return TRUE;
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}
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void
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_priv_gst_meta_cleanup (void)
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{
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if (metainfo != NULL) {
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g_hash_table_foreach_remove (metainfo, (GHRFunc) notify_custom, NULL);
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g_hash_table_unref (metainfo);
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metainfo = NULL;
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}
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}
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/**
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* gst_meta_api_type_register:
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* @api: an API to register
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* @tags: (array zero-terminated=1): tags for @api
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*
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* Register and return a GType for the @api and associate it with
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* @tags.
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*
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* Returns: a unique GType for @api.
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*/
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GType
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gst_meta_api_type_register (const gchar * api, const gchar ** tags)
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{
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GType type;
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g_return_val_if_fail (api != NULL, 0);
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g_return_val_if_fail (tags != NULL, 0);
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GST_CAT_DEBUG (GST_CAT_META, "register API \"%s\"", api);
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type = g_pointer_type_register_static (api);
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if (type != G_TYPE_INVALID) {
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gint i;
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for (i = 0; tags[i]; i++) {
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GST_CAT_DEBUG (GST_CAT_META, " adding tag \"%s\"", tags[i]);
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g_type_set_qdata (type, g_quark_from_string (tags[i]),
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GINT_TO_POINTER (TRUE));
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}
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}
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g_type_set_qdata (type, GST_QUARK (TAGS), g_strdupv ((gchar **) tags));
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return type;
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}
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static gboolean
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custom_init_func (GstMeta * meta, gpointer params, GstBuffer * buffer)
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{
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GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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cmeta->structure = gst_structure_new_empty (g_type_name (meta->info->type));
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gst_structure_set_parent_refcount (cmeta->structure,
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&GST_MINI_OBJECT_REFCOUNT (buffer));
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return TRUE;
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}
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static void
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custom_free_func (GstMeta * meta, GstBuffer * buffer)
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{
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GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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gst_structure_set_parent_refcount (cmeta->structure, NULL);
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gst_structure_free (cmeta->structure);
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}
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static gboolean
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custom_transform_func (GstBuffer * transbuf, GstMeta * meta,
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GstBuffer * buffer, GQuark type, gpointer data)
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{
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GstCustomMeta *custom, *cmeta = (GstCustomMeta *) meta;
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GstMetaInfoImpl *info = (GstMetaInfoImpl *) meta->info;
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if (info->custom_transform_func)
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return info->custom_transform_func (transbuf, cmeta,
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buffer, type, data, info->custom_transform_user_data);
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if (GST_META_TRANSFORM_IS_COPY (type)) {
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custom = (GstCustomMeta *) gst_buffer_add_meta (transbuf, meta->info, NULL);
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gst_structure_set_parent_refcount (custom->structure, NULL);
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gst_structure_take (&custom->structure,
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gst_structure_copy (cmeta->structure));
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gst_structure_set_parent_refcount (custom->structure,
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&GST_MINI_OBJECT_REFCOUNT (transbuf));
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} else {
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return FALSE;
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}
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return TRUE;
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}
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static gboolean
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custom_serialize_func (const GstMeta * meta, GstByteArrayInterface * data,
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guint8 * version)
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{
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const GstCustomMeta *cmeta = (const GstCustomMeta *) meta;
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gchar *str = gst_structure_serialize_full (cmeta->structure,
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GST_SERIALIZE_FLAG_STRICT);
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if (str == NULL)
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return FALSE;
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gboolean ret = gst_byte_array_interface_append_data (data, (guint8 *) str,
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strlen (str) + 1);
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g_free (str);
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return ret;
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}
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static GstMeta *
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custom_deserialize_func (const GstMetaInfo * info, GstBuffer * buffer,
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const guint8 * data, gsize size, guint8 version)
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{
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if (version != 0 || size < 1 || data[size - 1] != '\0')
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return NULL;
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GstStructure *structure =
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gst_structure_new_from_string ((const gchar *) data);
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if (structure == NULL)
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return NULL;
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GstMeta *meta = gst_buffer_add_meta (buffer, info, NULL);
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GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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gst_structure_set_parent_refcount (cmeta->structure, NULL);
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gst_structure_take (&cmeta->structure, structure);
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gst_structure_set_parent_refcount (cmeta->structure,
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&GST_MINI_OBJECT_REFCOUNT (buffer));
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return meta;
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}
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/**
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* gst_custom_meta_get_structure:
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*
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* Retrieve the #GstStructure backing a custom meta, the structure's mutability
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* is conditioned to the writability of the #GstBuffer @meta is attached to.
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*
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* Returns: (transfer none): the #GstStructure backing @meta
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* Since: 1.20
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*/
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GstStructure *
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gst_custom_meta_get_structure (GstCustomMeta * meta)
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{
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g_return_val_if_fail (meta != NULL, NULL);
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g_return_val_if_fail (gst_meta_info_is_custom (((GstMeta *) meta)->info),
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NULL);
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return meta->structure;
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}
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/**
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* gst_custom_meta_has_name:
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*
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* Checks whether the name of the custom meta is @name
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*
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* Returns: Whether @name is the name of the custom meta
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* Since: 1.20
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*/
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gboolean
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gst_custom_meta_has_name (GstCustomMeta * meta, const gchar * name)
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{
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g_return_val_if_fail (meta != NULL, FALSE);
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g_return_val_if_fail (gst_meta_info_is_custom (((GstMeta *) meta)->info),
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FALSE);
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return gst_structure_has_name (meta->structure, name);
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}
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/**
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* gst_meta_register_custom:
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* @name: the name of the #GstMeta implementation
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* @tags: (array zero-terminated=1): tags for @api
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* @transform_func: (scope notified) (nullable): a #GstMetaTransformFunction
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* @user_data: (closure): user data passed to @transform_func
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* @destroy_data: #GDestroyNotify for user_data
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*
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* Register a new custom #GstMeta implementation, backed by an opaque
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* structure holding a #GstStructure.
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*
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* The registered info can be retrieved later with gst_meta_get_info() by using
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* @name as the key.
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*
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* The backing #GstStructure can be retrieved with
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* gst_custom_meta_get_structure(), its mutability is conditioned by the
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* writability of the buffer the meta is attached to.
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*
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* When @transform_func is %NULL, the meta and its backing #GstStructure
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* will always be copied when the transform operation is copy, other operations
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* are discarded, copy regions are ignored.
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*
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* Returns: (transfer none): a #GstMetaInfo that can be used to
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* access metadata.
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* Since: 1.20
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*/
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const GstMetaInfo *
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gst_meta_register_custom (const gchar * name, const gchar ** tags,
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GstCustomMetaTransformFunction transform_func,
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gpointer user_data, GDestroyNotify destroy_data)
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{
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gchar *api_name = g_strdup_printf ("%s-api", name);
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GType api;
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GstMetaInfo *info;
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GstMetaInfoImpl *impl;
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const GstMetaInfo *ret = NULL;
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g_return_val_if_fail (tags != NULL, NULL);
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g_return_val_if_fail (name != NULL, NULL);
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api = gst_meta_api_type_register (api_name, tags);
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g_free (api_name);
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if (api == G_TYPE_INVALID)
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goto done;
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info = gst_meta_info_new (api, name, sizeof (GstCustomMeta));
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if (info == NULL)
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goto done;
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impl = (GstMetaInfoImpl *) info;
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info->init_func = custom_init_func;
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info->free_func = custom_free_func;
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info->transform_func = custom_transform_func;
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info->serialize_func = custom_serialize_func;
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info->deserialize_func = custom_deserialize_func;
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impl->is_custom = TRUE;
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impl->custom_transform_func = transform_func;
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impl->custom_transform_user_data = user_data;
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impl->custom_transform_destroy_notify = destroy_data;
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ret = gst_meta_info_register (info);
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done:
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return ret;
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}
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/**
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* gst_meta_register_custom_simple:
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* @name: the name of the #GstMeta implementation
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*
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* Simplified version of gst_meta_register_custom(), with no tags and no
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* transform function.
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*
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* Returns: (transfer none): a #GstMetaInfo that can be used to access metadata.
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* Since: 1.24
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*/
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const GstMetaInfo *
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gst_meta_register_custom_simple (const gchar * name)
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{
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const gchar *tags[] = { NULL };
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return gst_meta_register_custom (name, tags, NULL, NULL, NULL);
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}
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/**
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* gst_meta_info_is_custom:
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*
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* Returns: whether @info was registered as a #GstCustomMeta with
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* gst_meta_register_custom()
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* Since:1.20
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*/
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gboolean
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gst_meta_info_is_custom (const GstMetaInfo * info)
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{
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g_return_val_if_fail (info != NULL, FALSE);
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return ((GstMetaInfoImpl *) info)->is_custom;
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}
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/**
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* gst_meta_api_type_has_tag:
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* @api: an API
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* @tag: the tag to check
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*
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* Check if @api was registered with @tag.
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*
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* Returns: %TRUE if @api was registered with @tag.
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*/
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gboolean
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gst_meta_api_type_has_tag (GType api, GQuark tag)
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{
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g_return_val_if_fail (api != 0, FALSE);
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g_return_val_if_fail (tag != 0, FALSE);
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return g_type_get_qdata (api, tag) != NULL;
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}
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/**
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* gst_meta_api_type_get_tags:
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* @api: an API
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*
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* Returns: (transfer none) (array zero-terminated=1) (element-type utf8): an array of tags as strings.
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*
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* Since: 1.2
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*/
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const gchar *const *
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gst_meta_api_type_get_tags (GType api)
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{
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const gchar **tags;
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g_return_val_if_fail (api != 0, FALSE);
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tags = g_type_get_qdata (api, GST_QUARK (TAGS));
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if (!tags[0])
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return NULL;
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return (const gchar * const *) tags;
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}
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|
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static const GstMetaInfo *
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gst_meta_register_internal (GType api, const gchar * impl, gsize size,
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GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
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GstMetaTransformFunction transform_func,
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GstMetaSerializeFunction serialize_func,
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GstMetaDeserializeFunction deserialize_func)
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{
|
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GstMetaInfo *info;
|
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if (init_func == NULL)
|
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g_critical ("Registering meta implementation '%s' without init function",
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impl);
|
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|
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info = gst_meta_info_new (api, impl, size);
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if (info == NULL)
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return NULL;
|
|
|
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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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info->serialize_func = serialize_func;
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info->deserialize_func = deserialize_func;
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((GstMetaInfoImpl *) info)->is_custom = FALSE;
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return gst_meta_info_register (info);
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}
|
|
|
|
/**
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|
* gst_meta_register: (skip):
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* @api: the type of the #GstMeta API
|
|
* @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
|
|
* @free_func: a #GstMetaFreeFunction
|
|
* @transform_func: a #GstMetaTransformFunction
|
|
*
|
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* Register a new #GstMeta implementation.
|
|
*
|
|
* The same @info can be retrieved later with gst_meta_get_info() by using
|
|
* @impl as the key.
|
|
*
|
|
* Returns: (transfer none): a #GstMetaInfo that can be used to
|
|
* access metadata.
|
|
*/
|
|
const GstMetaInfo *
|
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gst_meta_register (GType api, const gchar * impl, gsize size,
|
|
GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
|
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GstMetaTransformFunction transform_func)
|
|
{
|
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return gst_meta_register_internal (api, impl, size, init_func, free_func,
|
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transform_func, NULL, NULL);
|
|
}
|
|
|
|
/**
|
|
* gst_meta_info_new: (skip):
|
|
* @api: the type of the #GstMeta API
|
|
* @impl: the name of the #GstMeta implementation
|
|
* @size: the size of the #GstMeta structure
|
|
*
|
|
* Creates a new structure that needs to be filled before being
|
|
* registered. This structure should filled and then registered with
|
|
* gst_meta_info_register().
|
|
*
|
|
* Example:
|
|
* ```c
|
|
* const GstMetaInfo *
|
|
* gst_my_meta_get_info (void)
|
|
* {
|
|
* static const GstMetaInfo *meta_info = NULL;
|
|
*
|
|
* if (g_once_init_enter ((GstMetaInfo **) & meta_info)) {
|
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* GstMetaInfo *info = gst_meta_info_new (
|
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* gst_my_meta_api_get_type (),
|
|
* "GstMyMeta",
|
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* sizeof (GstMyMeta));
|
|
* const GstMetaInfo *meta = NULL;
|
|
*
|
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* info->init_func = my_meta_init;
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* info->free_func = my_meta_free;
|
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* info->transform_func = my_meta_transform;
|
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* info->serialize_func = my_meta_serialize;
|
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* info->deserialize_func = my_meta_deserialize;
|
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* meta = gst_meta_info_register (info);
|
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* g_once_init_leave ((GstMetaInfo **) & meta_info, (GstMetaInfo *) meta);
|
|
* }
|
|
*
|
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* return meta_info;
|
|
* }
|
|
* ```
|
|
*
|
|
* Returns: a new #GstMetaInfo that needs to be filled
|
|
*
|
|
* Since: 1.24
|
|
*/
|
|
|
|
GstMetaInfo *
|
|
gst_meta_info_new (GType api, const gchar * impl, gsize size)
|
|
{
|
|
GType type;
|
|
GstMetaInfo *info;
|
|
|
|
g_return_val_if_fail (api != 0, NULL);
|
|
g_return_val_if_fail (impl != NULL, NULL);
|
|
g_return_val_if_fail (size != 0, NULL);
|
|
|
|
/* first try to register the implementation name. It's possible
|
|
* that this fails because it was already registered. Don't warn,
|
|
* glib did this for us already. */
|
|
type = g_pointer_type_register_static (impl);
|
|
|
|
info = (GstMetaInfo *) g_new0 (GstMetaInfoImpl, 1);
|
|
info->api = api;
|
|
info->type = type;
|
|
info->size = size;
|
|
|
|
return info;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_info_register:
|
|
* @info: (transfer full): a new #GstMetaInfo created by gst_meta_info_new()
|
|
*
|
|
* Registers a new meta.
|
|
*
|
|
* Use the structure returned by gst_meta_info_new(), it consumes it and the
|
|
* structure shouldnt be used after. The one returned by the function can be
|
|
* kept.
|
|
*
|
|
* Returns: (transfer none): the registered meta
|
|
*
|
|
* Since: 1.24
|
|
*/
|
|
|
|
const GstMetaInfo *
|
|
gst_meta_info_register (GstMetaInfo * info)
|
|
{
|
|
if (info->type == G_TYPE_INVALID) {
|
|
g_free (info);
|
|
return NULL;
|
|
}
|
|
|
|
GST_CAT_DEBUG (GST_CAT_META,
|
|
"register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
|
|
g_type_name (info->type), g_type_name (info->api), info->size);
|
|
|
|
g_rw_lock_writer_lock (&lock);
|
|
g_hash_table_insert (metainfo,
|
|
(gpointer) g_intern_string (g_type_name (info->type)), (gpointer) info);
|
|
g_rw_lock_writer_unlock (&lock);
|
|
|
|
return info;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_get_info:
|
|
* @impl: the name
|
|
*
|
|
* Lookup a previously registered meta info structure by its implementation name
|
|
* @impl.
|
|
*
|
|
* Returns: (transfer none) (nullable): a #GstMetaInfo with @impl, or
|
|
* %NULL when no such metainfo exists.
|
|
*/
|
|
const GstMetaInfo *
|
|
gst_meta_get_info (const gchar * impl)
|
|
{
|
|
GstMetaInfo *info;
|
|
|
|
g_return_val_if_fail (impl != NULL, NULL);
|
|
|
|
g_rw_lock_reader_lock (&lock);
|
|
info = g_hash_table_lookup (metainfo, impl);
|
|
g_rw_lock_reader_unlock (&lock);
|
|
|
|
return info;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_get_seqnum:
|
|
* @meta: a #GstMeta
|
|
*
|
|
* Gets seqnum for this meta.
|
|
*
|
|
* Since: 1.16
|
|
*/
|
|
guint64
|
|
gst_meta_get_seqnum (const GstMeta * meta)
|
|
{
|
|
GstMetaItem *meta_item;
|
|
guint8 *p;
|
|
|
|
g_return_val_if_fail (meta != NULL, 0);
|
|
|
|
p = (guint8 *) meta;
|
|
p -= G_STRUCT_OFFSET (GstMetaItem, meta);
|
|
meta_item = (GstMetaItem *) p;
|
|
return meta_item->seq_num;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_compare_seqnum:
|
|
* @meta1: a #GstMeta
|
|
* @meta2: a #GstMeta
|
|
*
|
|
* Meta sequence number compare function. Can be used as #GCompareFunc
|
|
* or a #GCompareDataFunc.
|
|
*
|
|
* Returns: a negative number if @meta1 comes before @meta2, 0 if both metas
|
|
* have an equal sequence number, or a positive integer if @meta1 comes
|
|
* after @meta2.
|
|
*
|
|
* Since: 1.16
|
|
*/
|
|
gint
|
|
gst_meta_compare_seqnum (const GstMeta * meta1, const GstMeta * meta2)
|
|
{
|
|
guint64 seqnum1 = gst_meta_get_seqnum (meta1);
|
|
guint64 seqnum2 = gst_meta_get_seqnum (meta2);
|
|
|
|
if (seqnum1 == seqnum2)
|
|
return 0;
|
|
|
|
return (seqnum1 < seqnum2) ? -1 : 1;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_serialize:
|
|
* @meta: a #GstMeta
|
|
* @data: #GstByteArrayInterface to append serialization data
|
|
*
|
|
* Serialize @meta into a format that can be stored or transmitted and later
|
|
* deserialized by gst_meta_deserialize().
|
|
*
|
|
* This is only supported for meta that implements #GstMetaInfo.serialize_func,
|
|
* %FALSE is returned otherwise.
|
|
*
|
|
* Upon failure, @data->data pointer could have been reallocated, but @data->len
|
|
* won't be modified. This is intended to be able to append multiple metas
|
|
* into the same #GByteArray.
|
|
*
|
|
* Since serialization size is often the same for every buffer, caller may want
|
|
* to remember the size of previous data to preallocate the next.
|
|
*
|
|
* Returns: %TRUE on success, %FALSE otherwise.
|
|
*
|
|
* Since: 1.24
|
|
*/
|
|
gboolean
|
|
gst_meta_serialize (const GstMeta * meta, GstByteArrayInterface * data)
|
|
{
|
|
g_return_val_if_fail (meta != NULL, FALSE);
|
|
g_return_val_if_fail (data != NULL, FALSE);
|
|
|
|
if (meta->info->serialize_func != NULL) {
|
|
const gchar *name = g_type_name (meta->info->type);
|
|
guint32 name_len = strlen (name);
|
|
guint32 orig_len = data->len;
|
|
guint8 version = 0;
|
|
|
|
/* Format: [total size][name_len][name][\0][version][payload]
|
|
* Preallocate space for header but only write it on success because we
|
|
* don't have every info yet.
|
|
*/
|
|
guint8 header_size = 2 * sizeof (guint32) + name_len + 2;
|
|
if (!gst_byte_array_interface_set_size (data, data->len + header_size))
|
|
return FALSE;
|
|
if (meta->info->serialize_func (meta, data, &version)) {
|
|
guint8 *header = data->data + orig_len;
|
|
GST_WRITE_UINT32_LE (header + 0, data->len - orig_len);
|
|
GST_WRITE_UINT32_LE (header + 4, name_len);
|
|
memcpy (header + 8, name, name_len + 1);
|
|
header[header_size - 1] = version;
|
|
return TRUE;
|
|
}
|
|
// Serialization failed, rollback.
|
|
gst_byte_array_interface_set_size (data, orig_len);
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
typedef struct
|
|
{
|
|
GstByteArrayInterface parent;
|
|
GByteArray *data;
|
|
} ByteArrayImpl;
|
|
|
|
static gboolean
|
|
byte_array_impl_resize (GstByteArrayInterface * parent, gsize length)
|
|
{
|
|
ByteArrayImpl *self = (ByteArrayImpl *) parent;
|
|
|
|
g_byte_array_set_size (self->data, length);
|
|
parent->data = self->data->data;
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* gst_meta_serialize_simple:
|
|
* @meta: a #GstMeta
|
|
* @data: #GByteArray to append serialization data
|
|
*
|
|
* Same as gst_meta_serialize() but with a #GByteArray instead of
|
|
* #GstByteArrayInterface.
|
|
*
|
|
* Returns: %TRUE on success, %FALSE otherwise.
|
|
*
|
|
* Since: 1.24
|
|
*/
|
|
gboolean
|
|
gst_meta_serialize_simple (const GstMeta * meta, GByteArray * data)
|
|
{
|
|
ByteArrayImpl impl;
|
|
|
|
gst_byte_array_interface_init (&impl.parent);
|
|
impl.parent.data = data->data;
|
|
impl.parent.len = data->len;
|
|
impl.parent.resize = byte_array_impl_resize;
|
|
impl.data = data;
|
|
return gst_meta_serialize (meta, (GstByteArrayInterface *) & impl);
|
|
}
|
|
|
|
/**
|
|
* gst_meta_deserialize:
|
|
* @buffer: a #GstBuffer
|
|
* @data: serialization data obtained from gst_meta_serialize()
|
|
* @size: size of @data
|
|
* @consumed: (out): total size used by this meta, could be less than @size
|
|
*
|
|
* Recreate a #GstMeta from serialized data returned by
|
|
* gst_meta_serialize() and add it to @buffer.
|
|
*
|
|
* Note that the meta must have been previously registered by calling one of
|
|
* `gst_*_meta_get_info ()` functions.
|
|
*
|
|
* @consumed is set to the number of bytes that can be skipped from @data to
|
|
* find the next meta serialization, if any. In case of parsing error that does
|
|
* not allow to determine that size, @consumed is set to 0.
|
|
*
|
|
* Returns: (transfer none) (nullable): the metadata owned by @buffer, or %NULL.
|
|
*
|
|
* Since: 1.24
|
|
*/
|
|
GstMeta *
|
|
gst_meta_deserialize (GstBuffer * buffer, const guint8 * data, gsize size,
|
|
guint32 * consumed)
|
|
{
|
|
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
|
|
g_return_val_if_fail (data != NULL, NULL);
|
|
g_return_val_if_fail (consumed != NULL, NULL);
|
|
|
|
*consumed = 0;
|
|
|
|
/* Format: [total size][name_len][name][\0][version][payload] */
|
|
if (size < 2 * sizeof (guint32))
|
|
goto bad_header;
|
|
|
|
guint32 total_size = GST_READ_UINT32_LE (data + 0);
|
|
guint32 name_len = GST_READ_UINT32_LE (data + 4);
|
|
guint32 header_size = 2 * sizeof (guint32) + name_len + 2;
|
|
if (size < total_size || total_size < header_size)
|
|
goto bad_header;
|
|
|
|
guint8 version = data[header_size - 1];
|
|
const gchar *name = (const gchar *) (data + 2 * sizeof (guint32));
|
|
if (name[name_len] != '\0')
|
|
goto bad_header;
|
|
|
|
*consumed = total_size;
|
|
|
|
const GstMetaInfo *info = gst_meta_get_info (name);
|
|
if (info == NULL) {
|
|
GST_CAT_WARNING (GST_CAT_META,
|
|
"%s does not correspond to a registered meta", name);
|
|
return NULL;
|
|
}
|
|
|
|
if (info->deserialize_func == NULL) {
|
|
GST_CAT_WARNING (GST_CAT_META, "Meta %s does not support deserialization",
|
|
name);
|
|
return NULL;
|
|
}
|
|
|
|
const guint8 *payload = data + header_size;
|
|
guint32 payload_size = total_size - header_size;
|
|
GstMeta *meta =
|
|
info->deserialize_func (info, buffer, payload, payload_size, version);
|
|
if (meta == NULL) {
|
|
GST_CAT_WARNING (GST_CAT_META, "Failed to deserialize %s payload", name);
|
|
GST_CAT_MEMDUMP (GST_CAT_META, "Meta serialization payload", payload,
|
|
payload_size);
|
|
return NULL;
|
|
}
|
|
|
|
return meta;
|
|
|
|
bad_header:
|
|
GST_CAT_WARNING (GST_CAT_META, "Could not parse meta serialization header");
|
|
GST_CAT_MEMDUMP (GST_CAT_META, "Meta serialization data", data, size);
|
|
return NULL;
|
|
}
|