Gst.Meta

Fields

Name Type Access Description
flags Gst.MetaFlags r/w extra flags for the metadata
info Gst.MetaInfo r/w pointer to the Gst.MetaInfo

Methods

class api_type_get_tags (api)
class api_type_has_tag (api, tag)
class api_type_register (api, tags)
class get_info (impl)
class register (api, impl, size, init_func, free_func, transform_func)
  compare_seqnum (meta2)
  get_seqnum ()

Details

class Gst.Meta

The Gst.Meta structure should be included as the first member of a Gst.Buffer 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 Gst.MetaInfo 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 Gst.Buffer for how the metadata can be added, retrieved and removed from buffers.

classmethod api_type_get_tags(api)[source]
Parameters:api (GObject.GType) – an API
Returns:an array of tags as strings.
Return type:[str]

New in version 1.2.

classmethod api_type_has_tag(api, tag)[source]
Parameters:
Returns:

True if api was registered with tag.

Return type:

bool

Check if api was registered with tag.

classmethod api_type_register(api, tags)[source]
Parameters:
  • api (str) – an API to register
  • tags ([str]) – tags for api
Returns:

a unique GObject.GType for api.

Return type:

GObject.GType

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

classmethod get_info(impl)[source]
Parameters:impl (str) – the name
Returns:a Gst.MetaInfo with impl, or None when no such metainfo exists.
Return type:Gst.MetaInfo or None

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

classmethod register(api, impl, size, init_func, free_func, transform_func)[source]
Parameters:
Returns:

a Gst.MetaInfo that can be used to access metadata.

Return type:

Gst.MetaInfo or None

Register a new Gst.Meta implementation.

The same info can be retrieved later with Gst.Meta.get_info() by using impl as the key.

compare_seqnum(meta2)[source]
Parameters:meta2 (Gst.Meta) – a Gst.Meta
Returns:a negative number if self comes before meta2, 0 if both metas have an equal sequence number, or a positive integer if self comes after meta2.
Return type:int

Meta sequence number compare function. Can be used as GLib.CompareFunc or a GLib.CompareDataFunc.

New in version 1.16.

get_seqnum()[source]
Return type:int

Gets seqnum for this meta.

New in version 1.16.