@omi3/audio

A flexible audio management library for web applications.

Features

• Simple API for audio playback control
• Support for loading and playing audio files
• Volume control and seeking functionality
• Event-driven architecture for easy integration
• Built-in audio analysis capabilities

Installation

Install the package using npm or yarn:

npm install @omi3/audio

or

pnpm add @omi3/audio

Usage

Here's a basic example of how to use the library:

import { AudioChannel, EventHandler, Music } from '@omi3/audio';

const eventHandler: EventHandler = {
onPlay: () => console.log('Audio started playing'),
onPause: () => console.log('Audio paused'),
onEnded: () => console.log('Audio playback ended'),
onTimeUpdate: (time) => console.log(Current time: ${time}),
onError: (error) => console.error('Audio error:', error),
};
const audioChannel = new AudioChannel(eventHandler);
const music: Music = {
id: '1',
name: 'My Audio',
url: 'https://example.com/audio.mp3',
};
async function playAudio() {
await audioChannel.initialize();
await audioChannel.load(music);
await audioChannel.play();
}
playAudio();

API Reference

AudioChannel

The main class for managing audio playback.

Constructor

constructor(eventHandler: EventHandler, audioContextFactory?: () => AudioContext)

• eventHandler: An object implementing the EventHandler interface.
• audioContextFactory: (Optional) A function that returns an AudioContext instance.

Methods

• initialize(): Promise<void>: Initializes the audio context and sets up audio processing.
• load(music: Music): Promise<void>: Loads an audio file and prepares it for playback.
• play(): Promise<void>: Starts or resumes audio playback.
• pause(): void: Pauses audio playback.
• seek(time: number): void: Seeks to a specific time in the audio.
• setVolume(volume: number): void: Sets the volume of the audio (0 to 1).
• isPlaying(): boolean: Checks if audio is currently playing.
• dispose(): void: Disposes of the audio channel and releases resources.

EventHandler

An interface for handling audio events.

interface EventHandler {
  onPlay?: () => void;
  onPause?: () => void;
  onEnded?: () => void;
  onTimeUpdate?: (time: number) => void;
  onDurationChange?: (duration: number) => void;
  onError?: (error: Error) => void;
  onAnalyserCreated?: (analyser: AnalyserNode) => void;
}

Music

A simple interface for representing music data.

interface Music {
  id: string;
  name: string;
  url: string;
}

Advanced Usage

Audio Analysis

The AudioChannel class provides access to an AnalyserNode for audio visualization or analysis:

const eventHandler: EventHandler = {
  onAnalyserCreated: (analyser: AnalyserNode) => {
    // Use the analyser node for visualizations or further audio processing
    console.log('Analyser created:', analyser);
  },
};
const audioChannel = new AudioChannel(eventHandler);

Custom Audio Context

You can provide a custom audio context factory to the AudioChannel constructor:

const customAudioContextFactory = () => {
  return new (window.AudioContext || (window as any).webkitAudioContext)({
    latencyHint: 'interactive',
    sampleRate: 44100,
  });
};
const audioChannel = new AudioChannel(eventHandler, customAudioContextFactory);

Browser Compatibility

This library uses the Web Audio API, which is supported in all modern browsers. For older browsers, consider using a polyfill or fallback solution.

Contributing

Contributions are welcome! Please read our contributing guidelines and code of conduct before submitting pull requests.

License

This package is licensed under Apache-2.0 - see the LICENSE file for details.