Gst.ElementClass¶

Fields¶

Name	Type	Access	Description
change_state	`object`	r	called by set_state to perform an incremental state change
elementfactory	`Gst.ElementFactory`	r	the `Gst.ElementFactory` that creates these elements
get_state	`object`	r	get the state of the element
metadata	`object`	r	metadata for elements of this class
no_more_pads	`object`	r
numpadtemplates	`int`	r	the number of padtemplates
pad_added	`object`	r
pad_removed	`object`	r
pad_templ_cookie	`int`	r	changed whenever the padtemplates change
padtemplates	[`object`]	r	a `GLib.List` of `Gst.PadTemplate`
parent_class	`Gst.ObjectClass`	r	the parent class structure
post_message	`object`	r	called when a message is posted on the element. Chain up to the parent class’ handler to have it posted on the bus.
provide_clock	`object`	r	gets the `Gst.Clock` provided by the element
query	`object`	r	perform a `Gst.Query` on the element
release_pad	`object`	r	called when a request pad is to be released
request_new_pad	`object`	r	called when a new pad is requested
send_event	`object`	r	send a `Gst.Event` to the element
set_bus	`object`	r	set a `Gst.Bus` on the element
set_clock	`object`	r	set the `Gst.Clock` on the element
set_context	`object`	r	set a `Gst.Context` on the element
set_state	`object`	r	set a new state on the element
state_changed	`object`	r	called immediately after a new state was set.

Methods¶

	`add_metadata` (key, value)
	`add_pad_template` (templ)
	`add_static_metadata` (key, value)
	`add_static_pad_template` (static_templ)
	`add_static_pad_template_with_gtype` (static_templ, pad_type)
	`get_metadata` (key)
	`get_pad_template` (name)
	`get_pad_template_list` ()
	`set_metadata` (longname, classification, description, author)
	`set_static_metadata` (longname, classification, description, author)

Details¶

class Gst.ElementClass¶

GStreamer element class. Override the vmethods to implement the element functionality.

add_metadata(key, value)[source]¶

Parameters:

key (str) – the key to set
value (str) – the value to set

Set key with value as metadata in self.

add_pad_template(templ)[source]¶

Parameters:: templ (Gst.PadTemplate) – a Gst.PadTemplate to add to the element class.

Adds a padtemplate to an element class. This is mainly used in the _class_init functions of classes. If a pad template with the same name as an already existing one is added the old one is replaced by the new one.

templ's reference count will be incremented, and any floating reference will be removed (see gst_object_ref_sink())

add_static_metadata(key, value)[source]¶

Parameters:

key (str) – the key to set
value (str) – the value to set

Set key with value as metadata in self.

Same as Gst.ElementClass.add_metadata(), but value must be a static string or an inlined string, as it will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)

add_static_pad_template(static_templ)[source]¶

Parameters:: static_templ (Gst.StaticPadTemplate) – Gst.StaticPadTemplate to add as pad template to the element class.

Adds a pad template to an element class based on the static pad template templ. This is mainly used in the _class_init functions of element implementations. If a pad template with the same name already exists, the old one is replaced by the new one.

New in version 1.8.

add_static_pad_template_with_gtype(static_templ, pad_type)[source]¶

Parameters:

static_templ (Gst.StaticPadTemplate) – Gst.StaticPadTemplate to add as pad template to the element class.
pad_type (GObject.GType) – The GObject.GType of the pad to create

Adds a pad template to an element class based on the static pad template templ. This is mainly used in the _class_init functions of element implementations. If a pad template with the same name already exists, the old one is replaced by the new one.

New in version 1.14.

get_metadata(key)[source]¶

Parameters:: key (str) – the key to get
Returns:: the metadata for key.
Return type:: str

Get metadata with key in self.

get_pad_template(name)[source]¶

Parameters:: name (str) – the name of the Gst.PadTemplate to get.
Returns:: the Gst.PadTemplate with the given name, or None if none was found. No unreferencing is necessary.
Return type:: Gst.PadTemplate or None

Retrieves a padtemplate from self with the given name.

If you use this function in the GObject.InstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GObject.InstanceInitFunc here.

get_pad_template_list()[source]¶

Returns:: the GLib.List of pad templates.
Return type:: [Gst.PadTemplate]

Retrieves a list of the pad templates associated with self. The list must not be modified by the calling code.

If you use this function in the GObject.InstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GObject.InstanceInitFunc here.

set_metadata(longname, classification, description, author)[source]¶

Parameters:

longname (str) – The long English name of the element. E.g. “File Sink”
classification (str) – String describing the type of element, as an unordered list separated with slashes (‘/’). See draft-klass.txt of the design docs for more details and common types. E.g: “Sink/File”
description (str) – Sentence describing the purpose of the element. E.g: “Write stream to a file”
author (str) – Name and contact details of the author(s). Use \n to separate multiple author metadata. E.g: “Joe Bloggs <joe.blogs at foo.com>”

Sets the detailed information for a Gst.ElementClass.

This function is for use in _class_init functions only.

set_static_metadata(longname, classification, description, author)[source]¶

Parameters:

longname (str) – The long English name of the element. E.g. “File Sink”
classification (str) – String describing the type of element, as an unordered list separated with slashes (‘/’). See draft-klass.txt of the design docs for more details and common types. E.g: “Sink/File”
description (str) – Sentence describing the purpose of the element. E.g: “Write stream to a file”
author (str) – Name and contact details of the author(s). Use \n to separate multiple author metadata. E.g: “Joe Bloggs <joe.blogs at foo.com>”

Sets the detailed information for a Gst.ElementClass.

This function is for use in _class_init functions only.

Same as Gst.ElementClass.set_metadata(), but longname, classification, description, and author must be static strings or inlined strings, as they will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)