gstreamer/gst/gstmeta.c
2011-03-28 20:08:46 +02:00

165 lines
4.5 KiB
C

/* GStreamer
* Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.com>
*
* gstmeta.c: metadata operations
*
* 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:gstmeta
* @short_description: Buffer metadata
*
* Last reviewed on December 17th, 2009 (0.10.26)
*/
#include "gst_private.h"
#include "gstbuffer.h"
#include "gstmeta.h"
#include "gstinfo.h"
#include "gstutils.h"
static GHashTable *metainfo = NULL;
static GStaticRWLock lock = G_STATIC_RW_LOCK_INIT;
void
_gst_meta_init (void)
{
metainfo = g_hash_table_new (g_str_hash, g_str_equal);
}
/**
* gst_meta_register_info:
* @info: a #GstMetaInfo
*
* Register a #GstMetaInfo. The same @info can be retrieved later with
* gst_meta_get_info() by using @impl as the key.
*
* Returns: a #GstMetaInfo that can be used to access metadata.
*/
const GstMetaInfo *
gst_meta_register (const gchar * api, const gchar * impl, gsize size,
GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
GstMetaTransformFunction transform_func,
GstMetaSerializeFunction serialize_func,
GstMetaDeserializeFunction deserialize_func)
{
GstMetaInfo *info;
g_return_val_if_fail (api != NULL, NULL);
g_return_val_if_fail (impl != NULL, NULL);
g_return_val_if_fail (size != 0, NULL);
info = g_slice_new (GstMetaInfo);
info->api = g_quark_from_string (api);
info->impl = g_quark_from_string (impl);
info->size = size;
info->init_func = init_func;
info->free_func = free_func;
info->transform_func = transform_func;
info->serialize_func = serialize_func;
info->deserialize_func = deserialize_func;
GST_DEBUG ("register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
api, impl, size);
g_static_rw_lock_writer_lock (&lock);
g_hash_table_insert (metainfo, (gpointer) impl, (gpointer) info);
g_static_rw_lock_writer_unlock (&lock);
return info;
}
/**
* gst_meta_get_info:
* @name: the name
*
* Lookup a previously registered meta info structure by its @implementor name.
*
* Returns: a #GstMetaInfo with @name 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_static_rw_lock_reader_lock (&lock);
info = g_hash_table_lookup (metainfo, impl);
g_static_rw_lock_reader_unlock (&lock);
return info;
}
/* Timing metadata */
static void
meta_timing_transform (GstBuffer * transbuf, GstMetaTiming * meta,
GstBuffer * buffer, GstMetaTransformData * data)
{
GstMetaTiming *timing;
guint offset;
guint size;
if (data->type == GST_META_TRANSFORM_TRIM) {
GstMetaTransformSubbuffer *subdata = (GstMetaTransformSubbuffer *) data;
offset = subdata->offset;
size = subdata->size;
} else {
offset = 0;
size = gst_buffer_get_size (buffer);
}
GST_DEBUG ("trans called from buffer %p to %p, meta %p, %u-%u", buffer,
transbuf, meta, offset, size);
timing = gst_buffer_add_meta_timing (transbuf);
if (offset == 0) {
/* same offset, copy timestamps */
timing->pts = meta->pts;
timing->dts = meta->dts;
if (size == gst_buffer_get_size (buffer)) {
/* same size, copy duration */
timing->duration = meta->duration;
} else {
/* else clear */
timing->duration = GST_CLOCK_TIME_NONE;
}
} else {
timing->pts = -1;
timing->dts = -1;
timing->duration = -1;
}
timing->clock_rate = meta->clock_rate;
}
const GstMetaInfo *
gst_meta_timing_get_info (void)
{
static const GstMetaInfo *meta_info = NULL;
if (meta_info == NULL) {
meta_info = gst_meta_register ("GstMetaTiming", "GstMetaTiming",
sizeof (GstMetaTiming),
(GstMetaInitFunction) NULL,
(GstMetaFreeFunction) NULL,
(GstMetaTransformFunction) meta_timing_transform,
(GstMetaSerializeFunction) NULL, (GstMetaDeserializeFunction) NULL);
}
return meta_info;
}