PipeWire: Client Node

PipeWire 1.4.9

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Client Node

Allow clients to export processing nodes to the PipeWire daemon.

This module creates 2 export types, one for the PW_TYPE_INTERFACE_Node and another for the SPA_TYPE_INTERFACE_Node interfaces.

With pw_core_export(), objects of these types can be exported to the PipeWire server. All actions performed on the node locally will be visible to connecteced clients and scheduling of the Node will be performed.

Objects of the PW_TYPE_INTERFACE_Node interface can be made with pw_context_create_node(), for example. You would manually need to create and add an object of the SPA_TYPE_INTERFACE_Node interface. Exporting a SPA_TYPE_INTERFACE_Node directly will first wrap it in a PW_TYPE_INTERFACE_Node interface.

Usually this module is not used directly but through the Stream and Filter APIs, which provides API to implement the SPA_TYPE_INTERFACE_Node interface.

In some cases, it is possible to use this factory directly (the PipeWire JACK implementation does this). With pw_core_create_object() on the client-node factory will result in a PW_TYPE_INTERFACE_ClientNode proxy that can be used to control the server side created Node Impl.

Schematically, the client side Node Impl is wrapped in the ClientNode proxy and unwrapped by the server side resource so that all actions on the client side node are reflected on the server side node and server side actions are reflected in the client.

client side proxy server side resource
.------------------------------. .----------------------------------.
| PW_TYPE_INTERFACE_ClientNode | | PW_TYPE_INTERFACE_Node |
|.----------------------------.| IPC |.--------------------------------.|
|| PW_TYPE_INTERFACE_Node || -----> || SPA_TYPE_INTERFACE_Node ||
||.--------------------------.|| ||.------------------------------.||
||| SPA_TYPE_INTERFACE_Node ||| ||| PW_TYPE_INTERFACE_ClientNode |||
||| ||| ||| |||
||'--------------------------'|| ||'------------------------------'||
|'----------------------------'| |'--------------------------------'|
'------------------------------' '----------------------------------'

# Module Name

libpipewire-module-client-node

# Module Options

This module has no options.

# Properties for the create_object call

All properties are passed directly to the pw_context_create_node() call.

# Example configuration

The module is usually added to the config file of the main PipeWire daemon and the clients.

context.modules = [
{ name = libpipewire-module-client-node }
]

# See also

- module-spa-node-factory: make nodes from a factory