:right-sidebar: True

Meta
===================================================================

.. currentmodule:: gi.repository.Gst





.. class:: Meta(*args, **kwargs)
   :no-contents-entry:






:Constructors:

::

    Meta()





Methods
-------

.. rst-class:: interim-class

.. class:: Meta
   :no-index:


   .. method:: api_type_get_tags(api: type) -> list[str]

      


      .. versionadded:: 1.2





      :param api: an API





   .. method:: api_type_has_tag(api: type, tag: int) -> bool

      Check if ``api`` was registered with ``tag``.







      :param api: an API


      :param tag: the tag to check





   .. method:: api_type_register(api: str, tags: ~typing.Sequence[str]) -> type

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







      :param api: an API to register


      :param tags: tags for ``api``





   .. method:: compare_seqnum(meta2: ~gi.repository.Gst.Meta) -> int

      Meta sequence number compare function. Can be used as :obj:`~gi.repository.GLib.CompareFunc`
      or a :obj:`~gi.repository.GLib.CompareDataFunc`.



      .. versionadded:: 1.16





      :param meta2: a :obj:`~gi.repository.Gst.Meta`





   .. method:: deserialize(buffer: ~gi.repository.Gst.Buffer, data: int, size: int) -> tuple[~gi.repository.Gst.Meta | None, int]

      Recreate a :obj:`~gi.repository.Gst.Meta` from serialized data returned by
      :func:`~gi.repository.Gst.Meta.serialize` and add it to ``buffer``.

      Note that the meta must have been previously registered by calling one of
      ```gst_``*_meta_get_info ()` functions.

      ``consumed`` is set to the number of bytes that can be skipped from ``data`` to
      find the next meta serialization, if any. In case of parsing error that does
      not allow to determine that size, ``consumed`` is set to 0.



      .. versionadded:: 1.24





      :param buffer: a :obj:`~gi.repository.Gst.Buffer`


      :param data: serialization data obtained from :func:`~gi.repository.Gst.Meta.serialize`


      :param size: size of ``data``





   .. method:: get_info(impl: str) -> ~gi.repository.Gst.MetaInfo | None

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







      :param impl: the name





   .. method:: get_seqnum() -> int

      Gets seqnum for this meta.



      .. versionadded:: 1.16








   .. method:: register_custom(name: str, tags: ~typing.Sequence[str], transform_func: ~typing.Callable[[...], bool] | None = None, *user_data: ~typing.Any) -> ~gi.repository.Gst.MetaInfo

      Register a new custom :obj:`~gi.repository.Gst.Meta` implementation, backed by an opaque
      structure holding a :obj:`~gi.repository.Gst.Structure`.

      The registered info can be retrieved later with :func:`~gi.repository.Gst.Meta.get_info` by using
      ``name`` as the key.

      The backing :obj:`~gi.repository.Gst.Structure` can be retrieved with
      :func:`~gi.repository.Gst.CustomMeta.get_structure`, its mutability is conditioned by the
      writability of the buffer the meta is attached to.

      When ``transform_func`` is :const:`None`, the meta and its backing :obj:`~gi.repository.Gst.Structure`
      will always be copied when the transform operation is copy, other operations
      are discarded, copy regions are ignored.



      .. versionadded:: 1.20





      :param name: the name of the :obj:`~gi.repository.Gst.Meta` implementation


      :param tags: tags for ``api``


      :param transform_func: a :obj:`~gi.repository.Gst.MetaTransformFunction`


      :param user_data: user data passed to ``transform_func``





   .. method:: register_custom_simple(name: str) -> ~gi.repository.Gst.MetaInfo

      Simplified version of :func:`~gi.repository.Gst.Meta.register_custom`, with no tags and no
      transform function.



      .. versionadded:: 1.24





      :param name: the name of the :obj:`~gi.repository.Gst.Meta` implementation





   .. method:: serialize(data: ~gi.repository.Gst.ByteArrayInterface) -> bool

      Serialize ``meta`` into a format that can be stored or transmitted and later
      deserialized by :func:`~gi.repository.Gst.Meta.deserialize`.

      This is only supported for meta that implements :obj:`~gi.repository.Gst.MetaInfo`.serialize_func,
      :const:`False` is returned otherwise.

      Upon failure, ``data``->data pointer could have been reallocated, but ``data``->len
      won't be modified. This is intended to be able to append multiple metas
      into the same ``GByteArray``.

      Since serialization size is often the same for every buffer, caller may want
      to remember the size of previous data to preallocate the next.



      .. versionadded:: 1.24





      :param data: :obj:`~gi.repository.Gst.ByteArrayInterface` to append serialization data





   .. method:: serialize_simple(data: ~typing.Sequence[int]) -> bool

      Same as :func:`~gi.repository.Gst.Meta.serialize` but with a ``GByteArray`` instead of
      :obj:`~gi.repository.Gst.ByteArrayInterface`.



      .. versionadded:: 1.24





      :param data: ``GByteArray`` to append serialization data















Fields
------

.. rst-class:: interim-class

.. class:: Meta
   :no-index:
   

   .. attribute:: flags

      Extra flags for the metadata







   .. attribute:: info

      Pointer to the :obj:`~gi.repository.Gst.MetaInfo`