godot4-opus

A GDExtension that adds to Godot4 support for encoding voice data using the Opus Codec. This can be useful for those who want to implement VOIP systems for Godot4 games.

Overview

This extension adds a new node to Godot: Opus with three methods: encode, decode and decode_and_play.

These can be used to compress audio obtained AudioEffectCapture and then to decode it so it's usable in Godot again.

Usage is best illustrated in this demo: https://github.com/microtaur/godot4-p2p-voip

Most interesting part from the demo code illustrating how this works:

var _encoder := Opus.new()

...

func _audio_process():
	while true:
		if has_data() and active:
			var data = get_data()
			call_deferred("rpc", "play_data", data)
		else:
			OS.delay_msec(10)

...

func get_data() -> PackedFloat32Array:
	var data = effect.get_buffer(BUFFER_SIZE)
	return _encoder.encode(data)

...

@rpc("any_peer", "call_remote", "reliable")
func play_data(data: PackedFloat32Array) -> void:
	var id = client.multiplayer.get_remote_sender_id()
	_update_player_pool()
	_get_opus_instance(id).decode_and_play(_get_generator(id), data)

Building

In order to build this project, you need scons. Currently only Windows x64 (MSVC) is supported.

1. Clone repo with submodules (godot-cpp)

git clone --recurse-submodules https://github.com/microtaur/godot4-opus.git && cd godot4-opus

2. Build debug

scons

3. Build release

scons target=template_release

More information on building GDExtensions: https://docs.godotengine.org/pl/4.x/tutorials/scripting/gdextension/gdextension_cpp_example.html

Known limitations

• This is more POC than a production-ready solution although it's not too far from achieving this status. I'm using this code successfully in a scenario similar to the one presented in this demo: https://github.com/godotengine/godot-demo-projects/tree/master/networking/webrtc_signaling
• Buffer size must be == 480
• Quality settings are currently hardcoded. Bitrate is 24000; bandwith is OPUS_BANDWIDTH_SUPERWIDEBAND.
• At the moment this works only on Windows x64. I haven't tried other platforms. Pre-built version of libopus resides in 3rdparty directory.

License

This is MIT licensed. Project uses Opus Codec which is BSD-licensed.