Live Audio.js

A Web Audio API-based game audio synthesis and background music library for Ruby Live applications.


Features

- Synthesized Sound Effects: Classic game sounds including jump, coin, power-up, death, explosion, laser, and animal sounds.
- Background Music: Audio file playback with loop points and volume control.
- Audio Visualization: Real-time waveform display with quality monitoring.
- Anti-Clipping Protection: Built-in gain management to prevent audio distortion.
- Modular Architecture: Clean separation between sound synthesis, output routing, and visualization.
- Live.js Pattern Compliance: Follows established patterns from the Live.js ecosystem.

Usage

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``bash
npm install @socketry/live-audio
`

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`javascript
import { Audio } from '@socketry/live-audio';
import { MeowSound, ExplosionSound, BackgroundMusicSound } from '@socketry/live-audio/Live/Audio/Library.js';

// Audio.start() pattern - follows Live.js conventions
window.liveAudio = Audio.start();

// Add sounds using the controller
const meow = new MeowSound();
const explosion = new ExplosionSound();
const music = new BackgroundMusicSound('/assets/music.mp3', {
loopStart: 10.0,
loopEnd: 45.0
});

window.liveAudio.addSound('meow', meow);
window.liveAudio.addSound('explosion', explosion);
window.liveAudio.addSound('music', music);
window.liveAudio.setVolume(0.8);

// Play sounds anywhere in your app
window.liveAudio.playSound('meow');
`

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`javascript
import { Audio } from '@socketry/live-audio';
import { CoinSound, LaserSound } from '@socketry/live-audio/Live/Audio/Library.js';

const controller = Audio.start();

// Add and play sounds
const coin = new CoinSound();
const laser = new LaserSound();
controller.addSound('coin', coin);
controller.addSound('laser', laser);
controller.playSound('coin');
controller.setVolume(0.8);
`

API Reference

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The primary entry point following Live.js conventions.

#### Static Methods
- Audio.start(options) - Create a new controller instance (recommended)
- options.window - The window object to use (defaults to globalThis)
- Returns the controller instance
- Audio.Controller - Direct access to Controller class for advanced usage

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The main audio controller class that manages all sound playback and audio context.

#### Instance Methods
- addSound(name, soundInstance) - Add a sound instance to the controller
- playSound(name) - Play a sound by name
- stopSound(name) - Stop a sound by name
- stopAllSounds() - Stop all sounds
- listSounds() - Get array of available sound names
- removeSound(name) - Remove a sound from the controller
- setVolume(volume) - Set master volume (0.0 to 1.0)
- getSound(name) - Get direct access to a sound instance

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Base class for creating custom sound effects. Extend this class to create your own synthesized sounds.

`javascript
import { Sound } from '@socketry/live-audio';

class CustomSound extends Sound {
start(output) {
const audioContext = output.audioContext;
const oscillator = audioContext.createOscillator();
const gainNode = audioContext.createGain();

oscillator.type = 'sine';
oscillator.frequency.value = 440;

this.createEnvelope(audioContext, gainNode, 0.01, 0.1, 0.5, 0.2, 0.5);

oscillator.connect(gainNode);
gainNode.connect(output.input);

oscillator.start();
oscillator.stop(audioContext.currentTime + 0.5);
}
}
`

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Audio analysis and visualization component that provides real-time waveform display and audio quality monitoring.

- Clipping detection and visualization
- Audio pop/click detection
- Rolling peak level monitoring
- Real-time waveform display

Built-in Sound Library

The library includes a comprehensive collection of pre-built sound classes in Library.js:

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- JumpSound - Classic platform game jump sound
- CoinSound - Collectible pickup sound
- PowerUpSound - Power-up acquisition sound
- DeathSound - Game over sound
- ExplosionSound - Explosive sound with multiple rumble layers
- LaserSound - Sci-fi laser sound
- BeepSound - Simple notification beep
- BlipSound - Short UI interaction sound

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- MeowSound - Cat meow with frequency modulation
- BarkSound - Dog bark with formant filtering
- RoarSound - Lion roar with noise texture
- ChirpSound - Bird chirp sound
- HowlSound - Wolf howl with harmonic sweep
- DuckSound - Duck quack with FM synthesis
- AlienSound - Alien sound with ring modulation

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- BackgroundMusicSound(url, options) - Audio file background music with optional loop configuration
- Supports common web audio formats: MP3, WAV, OGG, AAC, FLAC, and others supported by the browser
- options.loop - Enable/disable looping (default: true)
- options.loopStart - Loop start time in seconds
- options.loopEnd - Loop end time in seconds
- options.volume - Playback volume (default: 0.8)

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`javascript
import { Audio } from '@socketry/live-audio';
import { MeowSound, ExplosionSound, BackgroundMusicSound } from '@socketry/live-audio/Live/Audio/Library.js';

const controller = Audio.start();

// Add sounds from the library
const meow = new MeowSound();
const explosion = new ExplosionSound();

// Background music examples:
// Default: loops entire track at 80% volume
const music1 = new BackgroundMusicSound('/assets/background.mp3');

// Custom loop points
const music2 = new BackgroundMusicSound('/assets/background.mp3', {
loopStart: 10.5,
loopEnd: 45.2
});

// No looping
const music3 = new BackgroundMusicSound('/assets/background.mp3', { loop: false });

// Custom volume
const music4 = new BackgroundMusicSound('/assets/background.mp3', {
volume: 0.6,
loopStart: 5.0,
loopEnd: 30.0
});

controller.addSound('meow', meow);
controller.addSound('explosion', explosion);
controller.addSound('music', music1);

// Play them
controller.playSound('meow');
controller.playSound('explosion');
controller.playSound('music');
`

Project Structure

The library follows Live.js ecosystem patterns with a clean modular architecture:

`
@socketry/live-audio/
├── Live/
│ ├── Audio.js # Main module - exports Controller, Sound, Visualizer
│ └── Audio/
│ ├── Controller.js # Audio controller with window-keyed shared instances
│ ├── Sound.js # Base Sound class for custom sounds
│ ├── Output.js # Audio routing and master volume control
│ ├── Visualizer.js # Real-time waveform visualization
│ └── Library.js # Collection of pre-built game sounds
└── test/
└── LiveAudio.js # Comprehensive test suite
`

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`javascript
// Main Audio namespace (recommended)
import { Audio } from '@socketry/live-audio';

// Essential classes for advanced usage
import { Controller, Sound } from '@socketry/live-audio';

// Full access including visualization
import { Controller, Sound, Visualizer, Output } from '@socketry/live-audio';

// Pre-built sound library - individual imports (recommended)
import { MeowSound, ExplosionSound, BackgroundMusicSound } from '@socketry/live-audio/Live/Audio/Library.js';

// Pre-built sound library - namespace import
import * as Library from '@socketry/live-audio/Live/Audio/Library.js';
`

Audio Context Management

The library automatically manages a shared AudioContext to avoid browser limitations and ensure optimal performance:

- Automatic context creation and resumption
- Safari compatibility with proper latency handling
- Shared instance pattern to prevent multiple contexts
- Graceful degradation when audio is unavailable

Browser Compatibility

- Modern browsers with Web Audio API support
- Handles browser autoplay policies
- Safari-specific optimizations for reduced latency
- Fallback behavior when audio context is unavailable

Contributing

We welcome contributions to this project.

1. Fork it.
2. Create your feature branch (git checkout -b my-new-feature).
3. Commit your changes (git commit -am 'Add some feature').
4. Push to the branch (git push origin my-new-feature`).
5. Create new Pull Request.

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In order to protect users of this project, we require all contributors to comply with the Developer Certificate of Origin. This ensures that all contributions are properly licensed and attributed.

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This project is best served by a collaborative and respectful environment. Treat each other professionally, respect differing viewpoints, and engage constructively. Harassment, discrimination, or harmful behavior is not tolerated. Communicate clearly, listen actively, and support one another. If any issues arise, please inform the project maintainers.

See Also

- lively — Ruby framework for building interactive web applications.
- live — Provides client-server communication using websockets.
- live-js — JavaScript client library for Live framework.