Node Web Audio API

Node.js bindings for the Rust implementation of the Web Audio API Specification

The goal of this library is to provide an implementation that is both efficient and exactly matches the browsers' API.

see orottier/web-audio-api-rs for the "real" audio guts
use napi-rs for the Node.js bindings

Install

npm install [--save] node-web-audio-api

Example Use

import { AudioContext, OscillatorNode, GainNode } from 'node-web-audio-api';
// or using old fashionned commonjs syntax:
// const { AudioContext, OscillatorNode, GainNode } = require('node-web-audio-api');

const audioContext = new AudioContext();

setInterval(() => {
  const now = audioContext.currentTime;

  const env = new GainNode(audioContext);
  env.connect(audioContext.destination);
  env.gain.value = 0;
  env.gain.setValueAtTime(0, now);
  env.gain.linearRampToValueAtTime(1, now + 0.02);
  env.gain.exponentialRampToValueAtTime(0.0001, now + 1);

  const osc = new OscillatorNode(audioContext);
  osc.frequency.value = 200 + Math.random() * 2800;
  osc.connect(env);
  osc.start(now);
  osc.stop(now + 1);
}, 80);

Running the Examples

To run all examples locally on your machine you will need to:

Install Rust toolchain

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Clone the repo and build the binary on your machine

git clone https://github.com/ircam-ismm/node-web-audio-api.git
cd node-web-audio-api
npm install
npm run build

Run the examples from the project's root directory

node examples/granular-scrub.mjs

Caveats

The async methods are not trully async for now and are just patched on the JS side. This will evolve once the "trully" async version of the methods are implemented in the upstream library.
On Raspberry Pi, the Linux arm gnueabihf binary provided only works on 32bit OS. We will provide a version for the 64 bit OS in the future.

Supported Platforms

	binaries	tested
Windows x64	✓
Windows arm64	✓
macOS x64	✓	✓
macOS aarch64	✓
Linux x64 gnu	✓
Linux arm gnueabihf (RPi)	✓	✓
Linux arm64 gnu (RPi)	✓	✓

Notes for Linux users

Using the library on Linux with the ALSA backend might lead to unexpected cranky sound with the default render size (i.e. 128 frames). In such cases, a simple workaround is to pass the playback latency hint when creating the audio context, which will increase the render size to 1024 frames:

const audioContext = new AudioContext({ latencyHint: 'playback' });

You can pass the WEB_AUDIO_LATENCY=playback env variable to all examples to create the audio context with the playback latency hint, e.g.:

WEB_AUDIO_LATENCY=playback node examples/amplitude-modulation.mjs

For real-time and interactive applications where low latency is crucial, you should instead rely on the JACK backend provided by cpal. By default the audio context will use that backend if a running JACK server is found.

Manual Build

If prebuilt binaries are not shippped for your platform, you will need to:

Install the Rust toolchain

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Install and build from github

git clone https://github.com/ircam-ismm/node-web-audio-api.git node_modules/node-web-audio-api
cd node_modules/node-web-audio-api
npm install
npm run build

The package will be built on your machine, which might take some time.

Be aware that the package won't be listed on your package.json file, and that it won't be re-installed if running npm install again. A possible workaround would be to include the above in a postinstall script.

Development notes

The npm postversion script rely on cargo-bump to maintain versions synced between the package.json and the Cargo.toml files. Therefore, you will need to install cargo-bump on your machine

cargo install cargo-bump

License

BSD-3-Clause

italoadler / node-web-audio-api