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/* GStreamer
* Copyright (C) 2009 Wim Taymans <wim.taymans@gmail.be>
*
* gstmeta.h: Header for Metadata structures
*
* 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.
*/
#ifndef __GST_META_H__
#define __GST_META_H__
G_BEGIN_DECLS
typedef struct _GstMeta GstMeta;
typedef struct _GstMetaInfo GstMetaInfo;
#define GST_META_CAST(meta) ((GstMeta *)(meta))
/**
* GstMetaFlags:
* @GST_META_FLAG_NONE: no flags
* @GST_META_FLAG_READONLY: metadata should not be modified
* @GST_META_FLAG_POOLED: metadata is managed by a bufferpool and should not
* be removed
* @GST_META_FLAG_LAST: additional flags can be added starting from this flag.
*
* Extra metadata flags.
*/
typedef enum {
GST_META_FLAG_NONE = 0,
GST_META_FLAG_READONLY = (1 << 0),
GST_META_FLAG_POOLED = (1 << 1),
GST_META_FLAG_LAST = (1 << 16)
} GstMetaFlags;
/**
* GST_META_FLAGS:
* @meta: a #GstMeta.
*
* A flags word containing #GstMetaFlags flags set on @meta
*/
#define GST_META_FLAGS(meta) (GST_META_CAST (meta)->flags)
/**
* GST_META_FLAG_IS_SET:
* @meta: a #GstMeta.
* @flag: the #GstMetaFlags to check.
*
* Gives the status of a specific flag on a metadata.
*/
#define GST_META_FLAG_IS_SET(meta,flag) !!(GST_META_FLAGS (meta) & (flag))
/**
* GST_META_FLAG_SET:
* @meta: a #GstMeta.
* @flag: the #GstMetaFlags to set.
*
* Sets a metadata flag on a metadata.
*/
#define GST_META_FLAG_SET(meta,flag) (GST_META_FLAGS (meta) |= (flag))
/**
* GST_META_FLAG_UNSET:
* @meta: a #GstMeta.
* @flag: the #GstMetaFlags to clear.
*
* Clears a metadata flag.
*/
#define GST_META_FLAG_UNSET(meta,flag) (GST_META_FLAGS (meta) &= ~(flag))
/**
* GstMeta:
* @flags: extra flags for the metadata
* @info: pointer to the #GstMetaInfo
*
* Base structure for metadata. Custom metadata will put this structure
* as the first member of their structure.
*/
struct _GstMeta {
GstMetaFlags flags;
const GstMetaInfo *info;
};
/**
* GstMetaInitFunction:
* @meta: a #GstMeta
* @params: parameters passed to the init function
* @buffer: a #GstBuffer
*
* Function called when @meta is initialized in @buffer.
*/
typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuffer *buffer);
/**
* GstMetaFreeFunction:
* @meta: a #GstMeta
* @buffer: a #GstBuffer
*
* Function called when @meta is freed in @buffer.
*/
typedef void (*GstMetaFreeFunction) (GstMeta *meta, GstBuffer *buffer);
/**
* gst_meta_transform_copy:
*
* GQuark for the "gst-copy" transform.
*/
GST_EXPORT GQuark _gst_meta_transform_copy;
#define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy)
/**
* GstMetaTransformCopy:
* @region: %TRUE if only region is copied
* @offset: the offset to copy, 0 if @region is %FALSE, otherwise > 0
* @size: the size to copy, -1 or the buffer size when @region is %FALSE
*
* Extra data passed to a "gst-copy" transform #GstMetaTransformFunction.
*/
typedef struct {
gboolean region;
gsize offset;
gsize size;
} GstMetaTransformCopy;
/**
* GstMetaTransformFunction:
* @transbuf: a #GstBuffer
* @meta: a #GstMeta
* @buffer: a #GstBuffer
* @type: the transform type
* @data: transform specific data.
*
* Function called for each @meta in @buffer as a result of performing a
* transformation on @transbuf. Additional @type specific transform data
* is passed to the function as @data.
*
* Implementations should check the @type of the transform and parse
* additional type specific fields in @data that should be used to update
* the metadata on @transbuf.
*
* Returns: %TRUE if the transform could be performed
*/
typedef gboolean (*GstMetaTransformFunction) (GstBuffer *transbuf,
GstMeta *meta, GstBuffer *buffer,
GQuark type, gpointer data);
/**
* GstMetaInfo:
* @api: tag indentifying the metadata structure and api
* @type: type indentifying the implementor of the api
* @size: size of the metadata
* @init_func: function for initializing the metadata
* @free_func: function for freeing the metadata
* @transform_func: function for transforming the metadata
* @tags: 0 terminated array of GQuarks describing what the metadata
* contains info about
*
* The #GstMetaInfo provides information about a specific metadata
* structure.
*/
struct _GstMetaInfo {
GType api;
GType type;
gsize size;
GstMetaInitFunction init_func;
GstMetaFreeFunction free_func;
GstMetaTransformFunction transform_func;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
GType gst_meta_api_type_register (const gchar *api,
const gchar **tags);
gboolean gst_meta_api_type_has_tag (GType api, GQuark tag);
const GstMetaInfo * gst_meta_register (GType api, const gchar *impl,
gsize size,
GstMetaInitFunction init_func,
GstMetaFreeFunction free_func,
GstMetaTransformFunction transform_func);
const GstMetaInfo * gst_meta_get_info (const gchar * impl);
/* some default tags */
GST_EXPORT GQuark _gst_meta_tag_memory;
/**
* GST_META_TAG_MEMORY:
*
* Metadata tagged with this tag depends on the particular memory
* or buffer that it is on.
*/
#define GST_META_TAG_MEMORY (_gst_meta_tag_memory)
G_END_DECLS
#endif /* __GST_META_H__ */
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