Meta

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.

Last reviewed on 2012-03-28 (0.11.3)

Members

Static functions

apiTypeHasTag
int apiTypeHasTag(GType api, GQuark tag)

Check if api was registered with tag.

apiTypeRegister
GType apiTypeRegister(string api, string[] tags)

Register and return a GType for the api and associate it with tags.

getInfo
GstMetaInfo* getInfo(string impl)

Lookup a previously registered meta info structure by its implementation name impl.

register
GstMetaInfo* register(GType api, string impl, gsize size, GstMetaInitFunction initFunc, GstMetaFreeFunction freeFunc, GstMetaTransformFunction transformFunc)

Register a new GstMeta implementation. The same info can be retrieved later with gst_meta_get_info() by using impl as the key.

Meta