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70 lines
2.6 KiB
Text
70 lines
2.6 KiB
Text
/** \page page_design Design
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A short overview of PipeWire's design.
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PipeWire is a media server that can run graphs of multimedia nodes.
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Nodes can run inside the server process or in separate processes,
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communicating with the server.
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PipeWire was designed to:
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- Be efficient for raw video using fd passing and audio with
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shared ringbuffers.
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- Be able to provide/consume/process media from any process.
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- Provide policy to restrict access to devices and streams.
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- Be easily extensible.
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Although an initial goal, the design is not limited to raw video
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only and should be able to handle compressed video and other
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media as well.
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PipeWire uses the \ref page_spa "SPA plugin API" for the nodes in the graph.
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SPA is designed for low-latency and efficient processing of any multimedia
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format. SPA also provides a number of helper utilities that are not available
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in the standard C library.
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Some of the application we intend to build:
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- v4l2 device provider: Provide controlled access to v4l2 devices
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and share one device between multiple processes.
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- gnome-shell video provider: GNOME Shell provides a node that
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gives the contents of the frame buffer for screen sharing or
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screen recording.
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- Audio server: Mix and playback multiple audio streams. The design
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is more like CRAS (Chromium audio server) than PulseAudio and with
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the added benefit that processing can be arranged in a graph.
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- Professional audio graph processing like JACK.
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- Media playback backend.
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# Protocol
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The native protocol and object model is similar to
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[Wayland](https://wayland.freedesktop.org) but with custom
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serialization/deserialization of messages. This is because the data structures
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in the messages are more complicated and not easily expressible in XML.
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See \ref page_module_protocol_native for details.
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# Extensibility
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The functionality of the server is implemented and extended with modules and
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extensions. Modules are server side bits of logic that hook into various
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places to provide extra features. This mostly means controlling the processing
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graph in some way. See \ref page_pipewire_modules for a list of current
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modules.
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Extensions are the client side version of the modules. Most extensions provide
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both a client side and server side init function. New interfaces or new object
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implementation can easily be added with modules/extensions.
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Some of the extensions that can be written:
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- Protocol extensions: A client/server side API (.h) together with protocol
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extensions and server/client side logic to implement a new object or
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interface.
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- A module to check security of method calls.
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- A module to automatically create, link or relink nodes.
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- A module to suspend idle nodes.
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*/
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