gstreamer/gst/gstmeta.h
Wim Taymans 4bc7ff8e3e meta: add metadata flags
Add metadata flags so that we can set extra properties of the metadata
2011-12-22 16:02:05 +01:00

189 lines
5.7 KiB
C

/* 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 #GstMetaFlag flags set on @meta
*/
#define GST_META_FLAGS(meta) (GST_META_CAST (meta)->flags)
/**
* GST_META_FLAG_IS_SET:
* @meta: a #GstMeta.
* @flag: the #GstMetaFlag 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 #GstMetaFlag 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 #GstMetaFlag 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;
};
/**
* GST_META_TRACE_NAME:
*
* The name used for tracing memory allocations.
*/
#define GST_META_TRACE_NAME "GstMeta"
/**
* 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);
/**
* GstMetaCopyFunction:
* @dest: a destination #GstBuffer
* @meta: a #GstMeta
* @buffer: a #GstBuffer
* @offset: an offset
* @size: a size
*
* Function called when the region at @offset and @size in @buffer is copied
* into @dest. The function should update the metadata on @dest using @meta.
*/
typedef void (*GstMetaCopyFunction) (GstBuffer *dest, GstMeta *meta,
GstBuffer *buffer, gsize offset, gsize size);
/**
* GstMetaTransformFunction:
* @transbuf: a #GstBuffer
* @meta: a #GstMeta
* @buffer: a #GstBuffer
* @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.
*
* Implementations should check the type of the transform @data and parse
* additional type specific field that should be used to perform the transform.
*/
typedef void (*GstMetaTransformFunction) (GstBuffer *transbuf, GstMeta *meta,
GstBuffer *buffer, 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
* @copy_func: function for copying the metadata
* @transform_func: function for transforming the metadata
*
* The #GstMetaInfo provides information about a specific metadata
* structure.
*/
struct _GstMetaInfo {
GQuark api;
GType type;
gsize size;
GstMetaInitFunction init_func;
GstMetaFreeFunction free_func;
GstMetaCopyFunction copy_func;
GstMetaTransformFunction transform_func;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
const GstMetaInfo * gst_meta_register (const gchar *api, const gchar *impl,
gsize size,
GstMetaInitFunction init_func,
GstMetaFreeFunction free_func,
GstMetaCopyFunction copy_func,
GstMetaTransformFunction transform_func);
const GstMetaInfo * gst_meta_get_info (const gchar * impl);
G_END_DECLS
#endif /* __GST_META_H__ */