/* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_META_H__
#define __GST_META_H__
#include <glib.h>
#include <gst/gstbytearrayinterface.h>
#include <gst/gststructure.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
* @GST_META_FLAG_LOCKED: metadata 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_LOCKED = (1 << 2),
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))
/**
* GST_META_TAG_MEMORY_STR:
*
* This metadata stays relevant as long as memory layout is unchanged.
* In hindsight, this tag should have been called "memory-layout".
*
* Since: 1.2
*/
#define GST_META_TAG_MEMORY_STR "memory"
/**
* GST_META_TAG_MEMORY_REFERENCE_STR:
*
* This metadata stays relevant until a deep copy is made.
*
* Since: 1.20.4
*/
#define GST_META_TAG_MEMORY_REFERENCE_STR "memory-reference"
/**
* 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;
};
/**
* GstCustomMeta.structure:
*
* #GstStructure containing custom metadata.
*
* Since: 1.24
*/
/**
* GstCustomMeta:
* @meta: parent #GstMeta
* @structure: a #GstStructure containing custom metadata. (Since: 1.24)
*
* Extra custom metadata. The @structure field is the same as returned by
* gst_custom_meta_get_structure().
*
* Since 1.24 it can be serialized using gst_meta_serialize() and
* gst_meta_deserialize(), but only if the #GstStructure does not contain any
* fields that cannot be serialized, see %GST_SERIALIZE_FLAG_STRICT.
*
* Since: 1.20
*/
typedef struct {
GstMeta meta;
GstStructure *structure;
} GstCustomMeta;
#include <gst/gstbuffer.h>
/**
* 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_API GQuark _gst_meta_transform_copy;
/**
* GST_META_TRANSFORM_IS_COPY:
* @type: a transform type
*
* Check if the transform type is a copy transform
*/
#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);
/**
* GstCustomMetaTransformFunction:
* @transbuf: a #GstBuffer
* @meta: a #GstCustomMeta
* @buffer: a #GstBuffer
* @type: the transform type
* @data: transform specific data.
* @user_data: user data passed when registering the meta
*
* Function called for each @meta in @buffer as a result of performing a
* transformation that yields @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
* Since: 1.20
*/
typedef gboolean (*GstCustomMetaTransformFunction) (GstBuffer *transbuf,
GstCustomMeta *meta, GstBuffer *buffer,
GQuark type, gpointer data, gpointer user_data);
/**
* GstMetaSerializeFunction:
* @meta: a #GstMeta
* @data: #GstByteArrayInterface to append serialization data
* @version: (out): version of the serialization format
*
* Serialize @meta into a format that can be stored or transmitted and later
* deserialized by #GstMetaDeserializeFunction.
*
* By default version is set to 0, it should be bumped if incompatible changes
* are made to the format so %GstMetaDeserializeFunction can deserialize each
* version.
*
* Returns: %TRUE on success, %FALSE otherwise.
*
* Since: 1.24
*/
typedef gboolean (*GstMetaSerializeFunction) (const GstMeta *meta,
GstByteArrayInterface *data, guint8 *version);
/**
* GstMetaDeserializeFunction:
* @info: #GstMetaInfo of the meta
* @buffer: a #GstBuffer
* @data: data obtained from #GstMetaSerializeFunction
* @size: size of data to avoid buffer overflow
*
* Recreate a #GstMeta from serialized data returned by
* #GstMetaSerializeFunction and add it to @buffer.
*
* Returns: (transfer none) (nullable): the metadata owned by @buffer, or %NULL.
*
* Since: 1.24
*/
typedef GstMeta *(*GstMetaDeserializeFunction) (const GstMetaInfo *info,
GstBuffer *buffer, const guint8 *data, gsize size, guint8 version);
/**
* GstMetaClearFunction:
* @buffer: a #GstBuffer
* @meta: a #GstMeta
*
* Clears the content of the meta. This will be called by the GstBufferPool
* when a pooled buffer is returned.
*
* Since: 1.24
*/
typedef void (*GstMetaClearFunction) (GstBuffer *buffer, GstMeta *meta);
/**
* GstAllocationMetaParamsAggregator:
* @aggregated_params: This structure will be updated with the
* combined parameters from both @params0 and @params1.
* @params0: a #GstStructure containing the new parameters to be aggregated.
* @params1: a #GstStructure containing the new parameters to be aggregated.
*
* The aggregator function will combine the parameters from @params0 and @param1
* and write the result back into @aggregated_params.
*
* Returns: %TRUE if the parameters were successfully aggregated, %FALSE otherwise.
*
* Since: 1.26
*/
typedef gboolean (*GstAllocationMetaParamsAggregator) (GstStructure ** aggregated_params,
const GstStructure * params0,
const GstStructure * params1);
/**
* GstMetaInfo.serialize_func:
*
* Function for serializing the metadata, or %NULL if not supported by this
* meta.
*
* Since: 1.24
*/
/**
* GstMetaInfo.deserialize_func:
*
* Function for deserializing the metadata, or %NULL if not supported by this
* meta.
*
* Since: 1.24
*/
/**
* GstMetaInfo.clear_func:
*
* Function for clearing the metadata, or %NULL if not supported by this
* meta. This is called by the buffer pool when a buffer is returned for
* pooled metas.
*
* Since: 1.24
*/
/**
* GstMetaInfo:
* @api: tag identifying the metadata structure and api
* @type: type identifying 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
* @serialize_func: function for serializing the metadata into a #GstStructure,
* or %NULL if not supported by this meta. (Since 1.24)
* @deserialize_func: function for deserializing the metadata from a
* #GstStructure, or %NULL if not supported by this meta. (Since 1.24)
*
* 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;
GstMetaSerializeFunction serialize_func;
GstMetaDeserializeFunction deserialize_func;
GstMetaClearFunction clear_func;
/* No padding needed, GstMetaInfo is always allocated by GStreamer and is
* not subclassable or stack-allocatable, so we can extend it as we please
* just like interfaces */
};
GST_API
GType gst_meta_api_type_register (const gchar *api,
const gchar **tags);
GST_API
gboolean gst_meta_api_type_has_tag (GType api, GQuark tag);
GST_API
gboolean gst_meta_api_type_aggregate_params (GType api,
GstStructure ** aggregated_params,
const GstStructure * params0,
const GstStructure * params1);
GST_API
void gst_meta_api_type_set_params_aggregator (GType api,
GstAllocationMetaParamsAggregator aggregator);
GST_API
const GstMetaInfo * gst_meta_register (GType api, const gchar *impl,
gsize size,
GstMetaInitFunction init_func,
GstMetaFreeFunction free_func,
GstMetaTransformFunction transform_func);
GST_API
GstMetaInfo * gst_meta_info_new (GType api,
const gchar *impl,
gsize size);
GST_API
const GstMetaInfo * gst_meta_info_register (GstMetaInfo *info);
GST_API
const GstMetaInfo * gst_meta_register_custom (const gchar *name, const gchar **tags,
GstCustomMetaTransformFunction transform_func,
gpointer user_data, GDestroyNotify destroy_data);
GST_API
const GstMetaInfo * gst_meta_register_custom_simple (const gchar *name);
GST_API
gboolean gst_meta_info_is_custom (const GstMetaInfo *info);
GST_API
GstStructure * gst_custom_meta_get_structure (GstCustomMeta *meta);
GST_API
gboolean gst_custom_meta_has_name (GstCustomMeta *meta, const gchar * name);
GST_API
const GstMetaInfo * gst_meta_get_info (const gchar * impl);
GST_API
const gchar* const* gst_meta_api_type_get_tags (GType api);
GST_API
gboolean gst_meta_api_type_tags_contain_only (GType api, const gchar ** valid_tags);
GST_API
guint64 gst_meta_get_seqnum (const GstMeta * meta);
GST_API
gint gst_meta_compare_seqnum (const GstMeta * meta1,
const GstMeta * meta2);
GST_API
gboolean gst_meta_serialize (const GstMeta *meta,
GstByteArrayInterface *data);
GST_API
gboolean gst_meta_serialize_simple (const GstMeta *meta,
GByteArray *data);
GST_API
GstMeta * gst_meta_deserialize (GstBuffer *buffer,
const guint8 *data,
gsize size,
guint32 *consumed);
/* some default tags */
GST_API GQuark _gst_meta_tag_memory;
GST_API GQuark _gst_meta_tag_memory_reference;
/**
* GST_META_TAG_MEMORY:
*
* Metadata tagged with this tag depends on the particular memory
* or buffer that it is on.
*
* Deprecated: The GQuarks are not exported by any public API, use
* GST_META_TAG_MEMORY_STR instead.
*/
#ifndef GST_DISABLE_DEPRECATED
#define GST_META_TAG_MEMORY (_gst_meta_tag_memory)
#endif
G_END_DECLS
#endif /* __GST_META_H__ */