Gst.Meta¶
Fields¶
Name |
Type |
Access |
Description |
---|---|---|---|
flags |
r/w |
extra flags for the metadata |
|
info |
r/w |
pointer to the |
Methods¶
class |
|
class |
|
class |
|
class |
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class |
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class |
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Details¶
- class Gst.Meta¶
The
Gst.Meta
structure should be included as the first member of aGst.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. WithGst.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 aGst.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:
api (
GObject.GType
) – an APItag (
int
) – the tag to check
- Returns:
True
if api was registered with tag.- Return type:
Check if api was registered with tag.
- classmethod api_type_register(api, tags)[source]¶
- Parameters:
- Returns:
a unique
GObject.GType
for api.- Return type:
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, orNone
when no such metainfo exists.- Return type:
Gst.MetaInfo
orNone
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:
api (
GObject.GType
) – the type of theGst.Meta
APIinit_func (
Gst.MetaInitFunction
) – aGst.MetaInitFunction
free_func (
Gst.MetaFreeFunction
) – aGst.MetaFreeFunction
transform_func (
Gst.MetaTransformFunction
) – aGst.MetaTransformFunction
- Returns:
a
Gst.MetaInfo
that can be used to access metadata.- Return type:
Register a new
Gst.Meta
implementation.The same info can be retrieved later with
Gst.Meta.get_info
() by using impl as the key.
- classmethod register_custom(name, tags, transform_func, *user_data)[source]¶
- Parameters:
tags ([
str
]) – tags for apitransform_func (
Gst.CustomMetaTransformFunction
orNone
) – aGst.MetaTransformFunction
user_data (
object
orNone
) – user data passed to transform_func
- Returns:
a
Gst.MetaInfo
that can be used to access metadata.- Return type:
Register a new custom
Gst.Meta
implementation, backed by an opaque structure holding aGst.Structure
.The registered info can be retrieved later with
Gst.Meta.get_info
() by using name as the key.The backing
Gst.Structure
can be retrieved withGst.CustomMeta.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 backingGst.Structure
will always be copied when the transform operation is copy, other operations are discarded, copy regions are ignored.New in version 1.20.
- compare_seqnum(meta2)[source]¶
- Parameters:
- 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:
Meta sequence number compare function. Can be used as
GLib.CompareFunc
or aGLib.CompareDataFunc
.New in version 1.16.