extra flags for the metadata
pointer to the #GstMetaInfo
Meta sequence number compare function. Can be used as #GCompareFunc or a #GCompareDataFunc.
a #GstMeta
Gets seqnum for this meta.
Check if api
was registered with tag
.
an API
the tag to check
Register and return a GType for the api
and associate it with
tags
.
an API to register
tags for api
Register a new #GstMeta implementation.
The same info
can be retrieved later with gst_meta_get_info() by using
impl
as the key.
the type of the #GstMeta API
the name of the #GstMeta implementation
the size of the #GstMeta structure
a #GstMetaInitFunction
a #GstMetaFreeFunction
a #GstMetaTransformFunction
Register a new custom #GstMeta implementation, backed by an opaque structure holding a #GstStructure.
The registered info can be retrieved later with gst_meta_get_info() by using
name
as the key.
The backing #GstStructure can be retrieved with gst_custom_meta_get_structure(), its mutability is conditioned by the writability of the buffer the meta is attached to.
When transform_func
is %NULL, the meta and its backing #GstStructure
will always be copied when the transform operation is copy, other operations
are discarded, copy regions are ignored.
the name of the #GstMeta implementation
tags for api
a #GstMetaTransformFunction
The #GstMeta structure should be included as the first member of a #GstBuffer metadata structure. The structure defines the API of the metadata and should be accessible to all elements using the metadata.
A metadata API is registered with gst_meta_api_type_register() which takes a name for the metadata API and some tags associated with the metadata. With gst_meta_api_type_has_tag() one can check if a certain metadata API contains a given tag.
Multiple implementations of a metadata API can be registered. To implement a metadata API, gst_meta_register() should be used. This function takes all parameters needed to create, free and transform metadata along with the size of the metadata. The function returns a #GstMetaInfo structure that contains the information for the implementation of the API.
A specific implementation can be retrieved by name with gst_meta_get_info().
See #GstBuffer for how the metadata can be added, retrieved and removed from buffers.