Class (GI Struct)

Gst-1.0 ▶ 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.

Index

Constructors

constructor

new Meta(): Meta
Returns Meta

Properties

flags

flags: Gst.MetaFlags

`Static`$gtype

$gtype: GType<Meta>

Methods

compare_seqnum

compare_seqnum(meta2: Meta): number
Meta sequence number compare function. Can be used as GLib.CompareFunc or a GLib.CompareDataFunc.
Parameters
- meta2: Meta
  a Gst.Meta
Returns number
a negative number if meta1 comes before meta2, 0 if both metas have an equal sequence number, or a positive integer if meta1 comes after meta2.
- Defined in gst-1.0/gst-1.0.d.ts:20973

get_seqnum

get_seqnum(): number
Gets seqnum for this meta.

Returns number
- Defined in gst-1.0/gst-1.0.d.ts:20977

serialize

serialize(data: ByteArrayInterface): boolean
Serialize meta into a format that can be stored or transmitted and later deserialized by gst_meta_deserialize().

This is only supported for meta that implements Gst.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 GLib.ByteArray.

Since serialization size is often the same for every buffer, caller may want to remember the size of previous data to preallocate the next.
Parameters
- data: ByteArrayInterface
  Gst.ByteArrayInterface to append serialization data
Returns boolean
true on success, false otherwise.
- Defined in gst-1.0/gst-1.0.d.ts:20994

serialize_simple

serialize_simple(data: string | Uint8Array<ArrayBufferLike>): boolean
Same as gst_meta_serialize() but with a GLib.ByteArray instead of Gst.ByteArrayInterface.
Parameters
- data: string | Uint8Array<ArrayBufferLike>
  GLib.ByteArray to append serialization data
Returns boolean
true on success, false otherwise.
- Defined in gst-1.0/gst-1.0.d.ts:21001

`Static`api_type_aggregate_params

api_type_aggregate_params(
    api: GType,
    aggregated_params: Structure,
    params0: Structure,
    params1: Structure,
): boolean
When a element like tee decides the allocation, each downstream element may fill different parameters and pass them to gst_query_add_allocation_meta(). In order to keep these parameters, a merge operation is needed. This aggregate function can combine the parameters from params0 and param1, and write the result back into aggregated_params.
Parameters
- api: GType
  the GType of the API for which the parameters are being aggregated.
- aggregated_params: Structure
  This structure will be updated with the combined parameters from both params0 and params1.
- params0: Structure
  a Gst.Structure containing the new parameters to be aggregated.
- params1: Structure
  a Gst.Structure containing the new parameters to be aggregated.
Returns boolean
- Defined in gst-1.0/gst-1.0.d.ts:20885

`Static`api_type_get_tags

api_type_get_tags(api: GType): string[]
Parameters
- api: GType
  an API
Returns string[]
- Defined in gst-1.0/gst-1.0.d.ts:20894

`Static`api_type_has_tag

api_type_has_tag(api: GType, tag: number): boolean
Check if api was registered with tag.
Parameters
- api: GType
  an API
- tag: number
  the tag to check
Returns boolean
- Defined in gst-1.0/gst-1.0.d.ts:20900

`Static`api_type_register

api_type_register(api: string, tags: string[]): GType
Register and return a GType for the api and associate it with tags.
Parameters
- api: string
  an API to register
- tags: string[]
  tags for api
Returns GType
- Defined in gst-1.0/gst-1.0.d.ts:20907

`Static`api_type_set_params_aggregator

api_type_set_params_aggregator(
api: GType,
aggregator: AllocationMetaParamsAggregator,
): void
This function sets the aggregator function for a specific API type.
Parameters
- api: GType
  the GObject.GType of the API for which the aggregator function is being set.
- aggregator: AllocationMetaParamsAggregator
  the aggregator function to be associated with the given API type.
Returns void
- Defined in gst-1.0/gst-1.0.d.ts:20913

`Static`deserialize

deserialize(buffer: Gst.Buffer, data: number, size: number): [Meta, number]
Recreate a Gst.Meta from serialized data returned by 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.
Parameters
- buffer: Gst.Buffer
  a Gst.Buffer
- data: number
  serialization data obtained from gst_meta_serialize()
- size: number
  size of data
Returns [Meta, number]
- Defined in gst-1.0/gst-1.0.d.ts:20928

`Static`get_info

get_info(impl: string): Gst.MetaInfo
Lookup a previously registered meta info structure by its implementation name impl.
Parameters
- impl: string
  the name
Returns Gst.MetaInfo
- Defined in gst-1.0/gst-1.0.d.ts:20934

`Static`register_custom

register_custom(
    name: string,
    tags: string[],
    transform_func?: CustomMetaTransformFunction,
): Gst.MetaInfo
Register a new custom Gst.Meta implementation, backed by an opaque structure holding a Gst.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 with gst_custom_meta_get_structure(), its mutability is conditioned by the writability of the buffer the meta is attached to.

When transform_func is null, the meta and its backing Gst.Structure will always be copied when the transform operation is copy, other operations are discarded, copy regions are ignored.
Parameters
- name: string
  the name of the Gst.Meta implementation
- tags: string[]
  tags for api
- Optionaltransform_func: CustomMetaTransformFunction
  a Gst.MetaTransformFunction
Returns Gst.MetaInfo
- Defined in gst-1.0/gst-1.0.d.ts:20953

`Static`register_custom_simple

register_custom_simple(name: string): Gst.MetaInfo
Simplified version of gst_meta_register_custom(), with no tags and no transform function.
Parameters
- name: string
  the name of the Gst.Meta implementation
Returns Gst.MetaInfo
- Defined in gst-1.0/gst-1.0.d.ts:20963

Gst-1.0 ▶ Gst ▶ Meta

Index

Constructors

Properties

Methods

Constructors

constructor

Returns Meta

Properties

flags

Static$gtype

Methods

compare_seqnum

Parameters

Returns number

get_seqnum

Returns number

serialize

Parameters

Returns boolean

serialize_simple

Parameters

Returns boolean

Staticapi_type_aggregate_params

Parameters

Returns boolean

Staticapi_type_get_tags

Parameters

Returns string[]

Staticapi_type_has_tag

Parameters

Returns boolean

Staticapi_type_register

Parameters

Returns GType

Staticapi_type_set_params_aggregator

Parameters

Returns void

Staticdeserialize

Parameters

Returns [Meta, number]

Staticget_info

Parameters

Returns Gst.MetaInfo

Staticregister_custom

Parameters

Returns Gst.MetaInfo

Staticregister_custom_simple

Parameters

Returns Gst.MetaInfo

`Static`$gtype

`Static`api_type_aggregate_params

`Static`api_type_get_tags

`Static`api_type_has_tag

`Static`api_type_register

`Static`api_type_set_params_aggregator

`Static`deserialize

`Static`get_info

`Static`register_custom

`Static`register_custom_simple