Meta

class Meta(*args, **kwargs)
Constructors:

Meta()

Methods

class Meta
api_type_get_tags(api: type) → list[str]

Added in version 1.2.

Parameters:

api – an API

api_type_has_tag(api: type, tag: int) → bool

Check if api was registered with tag.

Parameters:

  • api – an API

  • tag – the tag to check

api_type_register(api: str, tags: Sequence[str]) → type

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

Parameters:

  • api – an API to register

  • tags – tags for api

compare_seqnum(meta2: Meta) → int

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

Added in version 1.16.

Parameters:

meta2 – a Meta

deserialize(buffer: Buffer, data: int, size: int) → tuple[Meta | None, int]

Recreate a Meta from serialized data returned by 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.

Added in version 1.24.

Parameters:

  • buffer – a Buffer

  • data – serialization data obtained from serialize()

  • size – size of data

get_info(impl: str) → MetaInfo | None

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

Parameters:

impl – the name

get_seqnum() → int

Gets seqnum for this meta.

Added in version 1.16.

register_custom(name: str, tags: Sequence[str], transform_func: Callable[[...], bool] | None = None, *user_data: Any) → MetaInfo

Register a new custom Meta implementation, backed by an opaque structure holding a Structure.

The registered info can be retrieved later with get_info() by using name as the key.

The backing Structure can be retrieved with get_structure(), its mutability is conditioned by the writability of the buffer the meta is attached to.

When transform_func is None, the meta and its backing Structure will always be copied when the transform operation is copy, other operations are discarded, copy regions are ignored.

Added in version 1.20.

Parameters:

  • name – the name of the Meta implementation

  • tags – tags for api

  • transform_func – a MetaTransformFunction

  • user_data – user data passed to transform_func

register_custom_simple(name: str) → MetaInfo

Simplified version of register_custom(), with no tags and no transform function.

Added in version 1.24.

Parameters:

name – the name of the Meta implementation

serialize(data: ByteArrayInterface) → bool

Serialize meta into a format that can be stored or transmitted and later deserialized by deserialize().

This is only supported for meta that implements MetaInfo.serialize_func, 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.

Added in version 1.24.

Parameters:

data – ByteArrayInterface to append serialization data

serialize_simple(data: Sequence[int]) → bool

Same as serialize() but with a GByteArray instead of ByteArrayInterface.

Added in version 1.24.

Parameters:

data – GByteArray to append serialization data

Fields

class Meta
flags

Extra flags for the metadata

info

Pointer to the MetaInfo