Package Exports

capacitor-audio-engine
capacitor-audio-engine/package.json

Readme

Capacitor Audio Engine 🎙️

Hey there! 👋 Welcome to the Native Audio plugin for Capacitor. This plugin makes it super easy to add both high-quality audio recording and powerful audio playback to your mobile apps. Whether you're building a voice memo app, a podcast player, a music app, or just need to record and play audio, we've got you covered!

📑 Table of Contents

Capacitor Audio Engine 🎙️

✨ Features

🎙️ Audio Recording

🎯 High-quality recording on Android and iOS
⏯️ Pause and resume your recordings seamlessly
🔄 Reset recordings without stopping (keeps settings, starts fresh)
📊 Real-time monitoring with duration tracking and recording status
🔒 Smart permission handling with detailed status information
✂️ Audio trimming to cut your recordings to the perfect length
📝 Rich metadata including file info, duration, sample rate, and more
🎙️ Microphone management - detect and switch between available microphones
🔍 Microphone status checking - know if the mic is busy with other apps
📊 Real-time waveform data - get audio levels for stunning visualizations
⚙️ Flexible configuration with quality presets and custom settings
🔧 Segment recording - automatic multi-segment recording for long sessions

🎵 Audio Playback

📂 Playlist management - load and control multiple audio tracks
▶️ Complete playback controls - play, pause, resume, stop with smooth transitions
⏭️ Track navigation - skip to next/previous or jump to any track by index
🎯 Precise seeking - jump to any position within tracks
📊 Real-time progress - get current position, duration, and playback status
🔔 Event notifications - track changes, completion, errors, and more
🔄 Auto-advance - automatically move to the next track
📱 Background support - continue playing when app is backgrounded
🎨 Rich metadata - support for track titles, artists, and artwork
⚡ Smart preloading - preload tracks for instant playback

🔧 Cross-Platform Excellence

📱 Native performance on Android and iOS
🎵 Consistent format - M4A/AAC across all platforms
🎚️ Quality control - from voice notes (16kHz) to high-quality music (48kHz)
🔄 Optimized defaults - 22.05kHz, 64kbps, mono for smaller file sizes
📐 Flexible options - choose quality presets or fine-tune every setting

📱 Platform Support

Feature	Android	iOS	Web
Audio Recording	✅	✅	🔜
Pause/Resume Recording	✅	✅	🔜
Permission Management	✅	✅	❌
Recording Status	✅	✅	🔜
Audio Trimming	✅	✅	❌
Microphone Detection	✅	✅	❌
Microphone Switching	✅	✅	❌
Waveform Data	✅	✅	❌
Audio Playback	✅	✅	🔜
Playlist Management	✅	✅	🔜
Background Playback	✅	✅	❌

💡 Note: Android and iOS are fully supported with all features! Web support is in development for core recording and playback features. 🚧

🚀 Installation

Prerequisites

Node.js 14+ and npm
Capacitor 5.0.0+
iOS 13+ for iOS development
Android 10+ (API level 29) for Android development

Setup

Install the plugin:

NPM:

npm i capacitor-audio-engine

PNPM:

pnpm add capacitor-audio-engine

YARN

yarn add capacitor-audio-engine

Sync your project:

npx cap sync

Add required permissions:

iOS

Add these to your Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>We need access to your microphone to record audio</string>

Android

Add this to your AndroidManifest.xml:

<uses-permission android:name="android.permission.RECORD_AUDIO" />

📖 API Documentation

Core Interfaces

`AudioFileInfo`

Information about recorded or audio files:

interface AudioFileInfo {
  path: string; // File system path
  webPath: string; // Web accessible path
  uri: string; // URI for file access
  mimeType: string; // MIME type (audio/m4a)
  size: number; // File size in bytes
  duration: number; // Duration in seconds
  sampleRate: number; // Audio sample rate (Hz)
  channels: number; // Number of audio channels
  bitrate: number; // Audio bitrate (bps)
  createdAt: number; // Creation timestamp
  filename: string; // File name
}

`RecordingOptions`

Configure your recording settings:

interface RecordingOptions {
  sampleRate?: AudioSampleRate | number; // Default: 22050 Hz
  channels?: AudioChannels | number; // Default: 1 (mono)
  bitrate?: AudioBitrate | number; // Default: 64000 bps
  maxDuration?: number; // Max duration in seconds
}

Recording Configuration Enums

Type-safe options for recording quality:

enum AudioSampleRate {
  VOICE_8K = 8000, // Basic voice recording
  VOICE_16K = 16000, // Good voice quality
  STANDARD_22K = 22050, // Standard quality (default)
  CD_44K = 44100, // CD quality
  HIGH_48K = 48000, // High quality
}

enum AudioChannels {
  MONO = 1, // Single channel (smaller files)
  STEREO = 2, // Two channels (stereo)
}

enum AudioBitrate {
  VERY_LOW = 16000, // Voice notes
  LOW = 32000, // Voice recording
  MEDIUM = 64000, // Balanced (default)
  HIGH = 128000, // Good quality
  VERY_HIGH = 256000, // Excellent quality
}

Permission Management

enum PermissionStatus {
  GRANTED = 'granted',
  DENIED = 'denied',
  DENIED_PERMANENTLY = 'denied_permanently',
  NOT_DETERMINED = 'not_determined',
  LIMITED = 'limited',
  RESTRICTED = 'restricted',
  REQUESTING = 'requesting',
  UNSUPPORTED = 'unsupported',
}

enum AudioPermissionType {
  MICROPHONE = 'microphone',
  NOTIFICATIONS = 'notifications',
}

interface PermissionStatusResults {
  granted: boolean; // permission status
  status: PermissionStatus; // status
}

Audio Playback

interface AudioTrack {
  id: string;
  url: string;
  title?: string;
  artist?: string;
  artworkUrl?: string;
}

interface PlaybackInfo {
  currentTrack: AudioTrack | null;
  currentIndex: number;
  currentPosition: number;
  duration: number;
  isPlaying: boolean;
  status: PlaybackStatus;
}

type PlaybackStatus = 'idle' | 'loading' | 'playing' | 'paused' | 'stopped';

Microphone Management

interface MicrophoneInfo {
  id: number;
  name: string;
  type: 'internal' | 'external' | 'unknown';
  description?: string;
  uid?: string; // iOS only
  isConnected?: boolean; // Android only
}

Waveform Configuration

enum WaveLevelEmissionInterval {
  REALTIME = 50, // 50ms - real-time
  VERY_FAST = 100, // 100ms - very fast
  FAST = 200, // 200ms - fast
  MEDIUM = 500, // 500ms - medium
  DEFAULT = 1000, // 1000ms - default
}

interface WaveLevelConfiguration {
  emissionInterval?: WaveLevelEmissionInterval | number;
}

Methods

Permission Management

`checkPermissions()`

Check the status of all audio-related permissions with detailed information:

checkPermissions(): Promise<PermissionStatusResults>;

Example:

const permissions = await CapacitorAudioEngine.checkPermissions();
console.log('Overall granted:', permissions.granted);
console.log('Microphone:', permissions.microphone.status);
console.log('Notifications:', permissions.notifications.status);

`checkPermissionMicrophone()`

Check only microphone permission status:

checkPermissionMicrophone(): Promise<SinglePermissionStatus>;

`checkPermissionNotifications()`

Check only notification permission status:

checkPermissionNotifications(): Promise<SinglePermissionStatus>;

`requestPermissions()`

Request permissions with detailed options and status:

requestPermissions(options?: PermissionRequestOptions): Promise<PermissionStatusResults>;

`openSettings()`

Navigate to app settings for manual permission management:

openSettings(): Promise<void>;

Recording Control

`startRecording()`

Start recording audio with optional configuration:

startRecording(options?: RecordingOptions): Promise<void>;

Example:

// Start with default settings (22.05kHz, 64kbps, mono)
await CapacitorAudioEngine.startRecording();

// Custom configuration
await CapacitorAudioEngine.startRecording({
  sampleRate: AudioSampleRate.CD_44K,
  channels: AudioChannels.STEREO,
  bitrate: AudioBitrate.HIGH,
  maxDuration: 300, // 5 minutes max
});

`pauseRecording()`

Pause the current recording:

pauseRecording(): Promise<void>;

`resumeRecording()`

Resume a paused recording:

resumeRecording(): Promise<void>;

`resetRecording()`

Reset the current recording session (keeps settings, discards data):

resetRecording(): Promise<void>;

`stopRecording()`

Stop recording and get the audio file information:

stopRecording(): Promise<AudioFileInfo>;

Status & Information

`getDuration()`

Get the current recording duration:

getDuration(): Promise<{ duration: number }>;

`getStatus()`

Get comprehensive recording status:

getStatus(): Promise<{
  status: RecordingStatus;
  isRecording: boolean;
  duration: number;
}>;

Audio Processing

`trimAudio()`

Trim an audio file to a specific duration:

trimAudio(options: { uri: string; start: number; end: number }): Promise<AudioFileInfo>;

Microphone Management

`isMicrophoneBusy()`

Check if the microphone is being used by another app:

isMicrophoneBusy(): Promise<MicrophoneStatusResult>;

`getAvailableMicrophones()`

Get a list of all available microphones:

getAvailableMicrophones(): Promise<AvailableMicrophonesResult>;

`switchMicrophone()`

Switch to a different microphone during recording:

switchMicrophone(options: SwitchMicrophoneOptions): Promise<SwitchMicrophoneResult>;

Waveform Configuration

`configureWaveform()`

Set up real-time audio level monitoring:

configureWaveform(options?: { EmissionInterval?: number }): Promise<WaveLevelConfigurationResult>;

Example:

// Configure with 200ms intervals
await CapacitorAudioEngine.configureWaveform({
  EmissionInterval: WaveLevelEmissionInterval.FAST,
});

// Listen for wave level events
await CapacitorAudioEngine.addListener('waveLevel', (data) => {
  console.log('Audio level:', data.level); // 0.0 to 1.0
});

`destroyWaveform()`

Clean up waveform configuration and resources:

destroyWaveform(): Promise<void>;

Audio Playback

`preloadTracks()`

Initialize a playlist with multiple audio tracks for optimized playback:

preloadTracks(options: PreloadTracksOptions): Promise<PreloadTracksResult>;

Example:

const result = await CapacitorAudioEngine.preloadTracks({
  tracks: ['https://example.com/song1.mp3', 'file:///path/to/local/song2.m4a', 'https://example.com/song3.mp3'],
  preloadNext: true,
});

console.log('Preloaded tracks:', result.tracks);

`playAudio()`

Start playback of the current track or a specific track:

playAudio(options?: PlayAudioOptions): Promise<void>;

`pauseAudio()`

Pause the current audio playback:

pauseAudio(options?: PauseAudioOptions): Promise<void>;

`resumeAudio()`

Resume paused audio playback:

resumeAudio(options?: ResumeAudioOptions): Promise<void>;

`stopAudio()`

Stop audio playback and reset to beginning:

stopAudio(options?: StopAudioOptions): Promise<void>;

`seekAudio()`

Seek to a specific position in the current track:

seekAudio(options: SeekOptions): Promise<void>;

Example:

// Seek to 30 seconds
await CapacitorAudioEngine.seekAudio({ seconds: 30 });

// Seek in specific track
await CapacitorAudioEngine.seekAudio({
  seconds: 45,
  url: 'https://example.com/track.mp3',
});

`skipToNext()`

Skip to the next track in the playlist:

skipToNext(): Promise<void>;

`skipToPrevious()`

Skip to the previous track in the playlist:

skipToPrevious(): Promise<void>;

`skipToIndex()`

Jump to a specific track by index:

skipToIndex(options: SkipToIndexOptions): Promise<void>;

Example:

// Jump to the third track (index 2)
await CapacitorAudioEngine.skipToIndex({ index: 2 });

`getPlaybackInfo()`

Get comprehensive playback information:

getPlaybackInfo(): Promise<PlaybackInfo>;

Example:

const info = await CapacitorAudioEngine.getPlaybackInfo();
console.log('Current track:', info.currentTrack?.title);
console.log('Position:', `${info.currentPosition}s / ${info.duration}s`);
console.log('Playing:', info.isPlaying);

Event Handling

`addListener()`

Listen for recording and playback events:

addListener<T extends AudioEventName>(
  eventName: T,
  callback: (event: AudioEventMap[T]) => void,
): Promise<PluginListenerHandle>;

Recording Events:

// Duration changes during recording
await CapacitorAudioEngine.addListener('durationChange', (data) => {
  console.log('Recording duration:', data.duration, 'seconds');
});

// Recording errors
await CapacitorAudioEngine.addListener('error', (data) => {
  console.error('Recording error:', data.message);
});

// Wave level data (requires configureWaveform)
await CapacitorAudioEngine.addListener('waveLevel', (data) => {
  console.log('Audio level:', data.level); // 0.0 to 1.0
  console.log('Timestamp:', data.timestamp);
});

// Wave level initialization
await CapacitorAudioEngine.addListener('waveLevelInit', (data) => {
  console.log('Waveform initialized:', data.status);
});

// Permission status changes
await CapacitorAudioEngine.addListener('permissionStatusChanged', (data) => {
  console.log('Permission changed:', data.permissionType, data.status);
});

Playback Events:

// Track changes
await CapacitorAudioEngine.addListener('trackChanged', (data) => {
  console.log('Track changed:', data.track.title, 'at index', data.index);
});

// Track completion
await CapacitorAudioEngine.addListener('trackEnded', (data) => {
  console.log('Track ended:', data.track.title);
});

// Playback start/pause
await CapacitorAudioEngine.addListener('playbackStarted', (data) => {
  console.log('Playback started:', data.track.title);
});

await CapacitorAudioEngine.addListener('playbackPaused', (data) => {
  console.log('Playback paused at:', data.position, 'seconds');
});

// Playback progress (every 500ms during playback)
await CapacitorAudioEngine.addListener('playbackProgress', (data) => {
  console.log(`Progress: ${data.currentPosition}/${data.duration}s`);
});

// Status changes
await CapacitorAudioEngine.addListener('playbackStatusChanged', (data) => {
  console.log('Status:', data.status, 'Playing:', data.isPlaying);
});

// Playback errors
await CapacitorAudioEngine.addListener('playbackError', (data) => {
  console.error('Playback error:', data.message);
});

`removeAllListeners()`

Remove all event listeners:

removeAllListeners(): Promise<void>;

Usage Example

Here's a complete example showing how to use the plugin:

import { CapacitorAudioEngine } from 'capacitor-audio-engine';
import { AudioSampleRate, AudioChannels, AudioBitrate, WaveLevelEmissionInterval } from 'capacitor-audio-engine';

class AudioManager {
  private isRecording = false;

  async initialize() {
    // Check permissions
    const permissions = await CapacitorAudioEngine.checkPermissions();
    if (!permissions.granted) {
      const result = await CapacitorAudioEngine.requestPermissions();
      if (!result.granted) {
        throw new Error('Permissions denied');
      }
    }

    // Set up event listeners
    await this.setupEventListeners();

    // Configure waveform monitoring
    await CapacitorAudioEngine.configureWaveform({
      EmissionInterval: WaveLevelEmissionInterval.FAST, // 200ms intervals
    });
  }

  async startRecording() {
    try {
      // Check if microphone is available
      const micStatus = await CapacitorAudioEngine.isMicrophoneBusy();
      if (micStatus.busy) {
        throw new Error(`Microphone busy: ${micStatus.reason}`);
      }

      // Start recording with high quality settings
      await CapacitorAudioEngine.startRecording({
        sampleRate: AudioSampleRate.CD_44K,
        channels: AudioChannels.MONO,
        bitrate: AudioBitrate.HIGH,
        maxDuration: 600, // 10 minutes max
      });

      this.isRecording = true;
      console.log('Recording started');
    } catch (error) {
      console.error('Failed to start recording:', error);
    }
  }

  async stopRecording() {
    try {
      const audioFile = await CapacitorAudioEngine.stopRecording();
      this.isRecording = false;
      console.log('Recording saved:', audioFile);
      return audioFile;
    } catch (error) {
      console.error('Failed to stop recording:', error);
    }
  }

  async playPlaylist(trackUrls: string[]) {
    try {
      // Preload tracks for better performance
      const preloadResult = await CapacitorAudioEngine.preloadTracks({
        tracks: trackUrls,
        preloadNext: true,
      });

      console.log('Preloaded tracks:', preloadResult.tracks);

      // Start playback
      await CapacitorAudioEngine.playAudio();
      console.log('Playback started');
    } catch (error) {
      console.error('Failed to start playback:', error);
    }
  }

  async switchMicrophone() {
    try {
      const mics = await CapacitorAudioEngine.getAvailableMicrophones();
      const externalMic = mics.microphones.find((mic) => mic.type === 'external');

      if (externalMic) {
        await CapacitorAudioEngine.switchMicrophone({
          microphoneId: externalMic.id,
        });
        console.log('Switched to external microphone');
      }
    } catch (error) {
      console.error('Failed to switch microphone:', error);
    }
  }

  private async setupEventListeners() {
    // Recording events
    await CapacitorAudioEngine.addListener('durationChange', (data) => {
      console.log('Duration:', data.duration);
    });

    await CapacitorAudioEngine.addListener('waveLevel', (data) => {
      // Update waveform visualization
      this.updateWaveform(data.level);
    });

    await CapacitorAudioEngine.addListener('error', (data) => {
      console.error('Recording error:', data.message);
    });

    // Playback events
    await CapacitorAudioEngine.addListener('trackChanged', (data) => {
      console.log('Now playing:', data.track.title);
    });

    await CapacitorAudioEngine.addListener('playbackProgress', (data) => {
      // Update progress bar
      this.updateProgress(data.currentPosition, data.duration);
    });
  }

  private updateWaveform(level: number) {
    // Update your waveform visualization UI
    // level is between 0.0 (silent) and 1.0 (loud)
  }

  private updateProgress(currentTime: number, duration: number) {
    // Update your progress bar UI
    const percentage = (currentTime / duration) * 100;
  }

  async cleanup() {
    await CapacitorAudioEngine.removeAllListeners();
    await CapacitorAudioEngine.destroyWaveform();
  }
}

// Usage
const audioManager = new AudioManager();
await audioManager.initialize();

Note: All audio files are saved in M4A format (MPEG-4/AAC) across all platforms for consistency.

� Troubleshooting

Common Issues

Permission Problems:

Make sure you've added the required permissions to your platform files
Check if permissions were granted in device settings
Use openSettings() to guide users to permission settings

Recording Issues:

Check if another app is using the microphone with isMicrophoneBusy()
Verify sufficient storage space is available
Try switching microphones if external ones are available

Playback Issues:

Ensure audio files are accessible and in supported formats
Check network connectivity for remote audio files
Verify the track was properly preloaded before playback

Performance Issues:

Use preloadTracks() for better playback performance
Configure appropriate maxDuration for long recordings
Clean up listeners and resources when no longer needed

🛠️ Technical Details

Platform-Specific Implementations

Android

Recording: MediaRecorder with AAC codec in M4A container
Playback: ExoPlayer for advanced playlist management
Format: M4A/AAC (audio/m4a)
Storage: App's external files directory under "Recordings" folder
Permissions: RECORD_AUDIO, FOREGROUND_SERVICE, POST_NOTIFICATIONS
Microphone Management: AudioManager.getDevices() for device enumeration
Background Support: Foreground service for continuous recording/playback

iOS

Recording: AVAudioRecorder with AAC codec in M4A container
Playback: AVQueuePlayer for playlist management
Format: M4A/AAC (audio/m4a)
Permissions: NSMicrophoneUsageDescription in Info.plist
Microphone Management: AVAudioSession.availableInputs for device enumeration
Background Support: Background audio mode for continuous operation

Web (In Development)

Recording: MediaRecorder API (when available)
Playback: HTML5 Audio API
Format: WebM/Opus for recording, various formats for playback
Limitations: Limited microphone management, no waveform data

Audio Quality Settings

The plugin uses optimized defaults that balance quality and file size:

Default: 22.05kHz, 64kbps, mono (medium quality)
Voice Notes: 16kHz, 32kbps, mono (smaller files)
High Quality: 44.1kHz, 128kbps, mono (better audio)
Custom: Any combination of supported sample rates, bitrates, and channels

File Format Consistency

All platforms use M4A/AAC format for maximum compatibility:

MIME Type: audio/m4a
Container: MPEG-4 Part 14 (.m4a)
Codec: Advanced Audio Coding (AAC)
Compatibility: Excellent across all platforms and devices

📚 Additional Documentation

For more detailed examples and advanced usage patterns, check out:

Microphone Management Guide - Comprehensive guide for microphone detection, switching, and troubleshooting

🤝 Contributing

We love contributions! Whether it's fixing bugs, adding features, or improving docs, your help makes this plugin better for everyone. Here's how to help:

Fork the repo
Create your feature branch (git checkout -b feature/amazing-feature)
Commit your changes (git commit -m 'Add amazing feature')
Push to the branch (git push origin feature/amazing-feature)
Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

📞 Need Help?

Found a bug? Have a feature request? Just want to chat? Open an issue on GitHub and we'll help you out!

Made with ❤️ by Abdelfattah Ashour