PulseAudio is an free cross-platform audio server. This addon may be usefull for creating PulseAudio clients on JS, which runs on NodeJS. You can retrieve source/sink info from server, create Record and Playback streams.
This module provides libuv-based MainLoop API for PulseAudio Context, it means that client uses same thread, where V8 runs. Mainloop API consists of three things: I/O Event Polling, Deferred Calls and Timers. Resolution of timers limited by milliseconds.
This is a fork of node-pulseaudio, which was unmaintained.
Install module with npm:
npm install pulseaudio2
Require and use:
var PulseAudio = require('pulseaudio');
var context = PulseAudio();
var player = context.createPlaybackStream();
player.write(data);
player.on('drain', function(){
player.end();
});
Context is a base communication point for client.
var context = new PulseAudio({
client: "my-awesome-app", // optional client name ("node-pulse" by default)
server: "my-preferred-server", // optional server name
flags: "noflags|noautospawn|nofail" // optional connection flags (see PulseAudio documentation)
});
You can listen context state.
context.on('state', function(state){
// state == "connecting|authorizing|setting_name|ready|terminated"
});
And exceptions errors.
context.on('error', function(error){
//
});
Before we can operating with context we may wait until connection will be established.
context.on('connection', function(){
// operations
context.end();
});
But usually it doesn't require, because any operations execute deferred.
How we can retrieve sink / source lists from server.
const list = await context.[sink|source]();
// list[0].name - name of first sink/source
And open streams.
Streams designed for sound i/o.
We can create record / playback streams.
var stream = context.createPlaybackStream({
stream: "my-awesome-stream", // optional stream name ("node-stream" by default)
device: "my-preferred-device", // optional device name
format: "U8|S(16|24|32)(LE|BE)|F32(BE|LE)|(A|U)LAW", // optional sample format ("S16LE" by default)
rate: 8000|22050|44100|48000|96000|192000|N, // optional sample rate (44100 by default)
channels: 1|2|N, // optional channels (2 (stereo) by default)
latency: 250000, // optional latency in microseconds
flags: 'adjust_latency|early_requests|...' // optional flags (see Pulseaudio docs)
});
But really streams will be initialized after context connection established.
You can monitor stream state.
stream.on('state', function(state){
// state == "creating|ready|terminated"
});
And stream errors.
stream.on('error', function(error){
//
});
Before we can operating with stream we must wait until connection will be established.
stream.on('connection', function(){
//
});
We can write / read data to / from stream by using NodeJS Stream API.
stream.write(chunk);
stream.on('data', function(chunk){
//
});
recorder.pipe(player);
// and many more
In addition, we may pause / resume streams by calling stop / play methods.
stream.stop();
stream.play();
Stopping discards any unplayed samples from stream.
Of course, we can listen stop / play events and check stopped / playing properties.
Note that we don't need to use pause / resume methods with sound streams.
This addon are available under GNU Lesser General Public License version 3 or later.
node-pulseaudio — PulseAudio integration addon for NodeJS.
Copyright © 2013 Kayo Phoenix kayo@illumium.org
2017-2019 The Board of Trustees of the Leland Stanford Junior University
This library is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this library. If not, see http://www.gnu.org/licenses/.