LiveVoxNative

A professional-grade real-time audio monitoring and analysis application built with React Native and Expo. LiveVoxNative provides low-latency audio input/output with advanced audio analysis capabilities including RMS metering, waveform visualization, and pitch detection.

Why

Same problem as LiveVox -- feed the mic into the headphone mix so you can hear yourself without sounding like a jackass. This is the native iOS implementation using Swift AVAudioEngine, built to get real latency numbers on physical hardware rather than browser estimates.

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📚 Documentation

• Quick Start Guide - Get up and running in 5 minutes
• API Reference - Complete audio engine API documentation
• Code Examples - Practical usage examples
• Contributing Guide - How to contribute to the project
• Changelog - Version history and release notes
• Documentation Overview - Navigate all documentation

Features

• Real-time Audio Monitoring: Low-latency audio input and output using AVAudioEngine
• Audio Analysis:
  • RMS (Root Mean Square) level metering
  • Waveform visualization
  • Pitch detection with note and cents display
• Latency Measurement:
  • Theoretical latency reporting (input, output, buffer)
  • Round-trip latency testing with click detection
• Flexible Audio Routing:
  • Select from available audio inputs (microphone, external devices)
  • Select from available audio outputs (speaker, headphones, external devices)
• Background Audio Control: Toggle between ducking mode (karaoke) and mixing with other apps
• Modern UI: Sleek dark-themed interface with smooth animations

Prerequisites

• macOS: Required for iOS development
• Xcode: Latest version recommended
• Node.js: v18 or higher
• npm or yarn: Package manager
• Expo CLI: Installed globally or via npx
• iOS Device or Simulator: iOS 13.0 or higher

Installation

1. Clone the repository:

   git clone https://github.com/JustLikeFrank3/LiveVoxNative.git
   cd LiveVoxNative

2. Install dependencies:

   npm install

3. Install iOS dependencies:

   cd ios
   pod install
   cd ..

Running the App

Development Mode

Start the Expo development server:

npm start

Run on iOS Simulator:

npm run ios

Run on iOS Device:

1. Connect your iOS device via USB
2. Ensure your device is registered in your Apple Developer account
3. Run:

   npm run ios

Production Build

To create a production build, use Expo's build service or EAS Build:

npx eas build --platform ios

Usage

Starting Audio Monitoring

1. Launch the app
2. Grant microphone permissions when prompted
3. Tap the Start button to begin monitoring
4. The app will display:
   • Real-time RMS levels
   • Waveform visualization
   • Pitch detection (note name, octave, and cents deviation)
   • Latency information

Selecting Audio Devices

• Audio Input: Tap on any available input device to switch (e.g., built-in microphone, external mic)
• Audio Output: Tap on any available output device to switch (e.g., speaker, headphones)

Measuring Latency

1. Make sure the audio engine is running
2. Tap Measure Real Latency in the Round-Trip Latency Test section
3. The app will play a click through the speaker and measure when it returns through the microphone
4. Results include measured latency, theoretical latency, and the difference

Background Audio Control

Toggle between two modes:

• Duck Other Apps (Karaoke Mode): Reduces other apps' volume by ~50%
• Mix With Other Apps: Allows other apps to play at full volume

Project Structure

LiveVoxNative/
├── App.tsx                 # Main application component
├── index.ts               # Entry point
├── app.json              # Expo configuration
├── package.json          # Project dependencies
├── modules/
│   └── audio-engine/     # Native audio engine module
│       ├── ios/          # iOS native implementation
│       ├── src/          # TypeScript/JavaScript interface
│       └── package.json  # Module metadata
├── assets/               # App icons and images
└── ios/                  # iOS project files

Audio Engine Module

The expo-audio-engine is a custom Expo module that provides native audio processing capabilities using Apple's AVAudioEngine framework.

Key Features

• Start/stop audio monitoring
• Get available audio inputs and outputs
• Switch between audio devices
• Real-time audio analysis (RMS, pitch, waveform)
• Latency measurement and reporting
• Background audio ducking control

API Reference

See modules/audio-engine/README.md for detailed API documentation.

Available Scripts

• npm start - Start the Expo development server
• npm run ios - Run the app on iOS simulator or device
• npm run android - Run the app on Android (not currently supported)
• npm run web - Run the app in a web browser (limited functionality)

Technical Details

Audio Processing

• Engine: AVAudioEngine (iOS)
• Sample Rate: Device-dependent (typically 48 kHz)
• Buffer Size: Optimized for low latency
• Analysis: Real-time FFT for pitch detection, time-domain analysis for RMS and waveform

Permissions

The app requires microphone access:

• iOS: NSMicrophoneUsageDescription is configured in app.json
• Users will be prompted to grant permission on first use

React Native New Architecture

This app is configured to use React Native's New Architecture:

• Turbo Modules for native module communication
• Fabric renderer for improved performance
• Set via newArchEnabled: true in app.json

Troubleshooting

Microphone Permission Issues

If the app cannot access the microphone:

1. Go to iOS Settings → Privacy → Microphone
2. Ensure LiveVoxNative has permission enabled

Audio Not Working

• Check that audio monitoring is started (tap Start button)
• Verify that the device is not muted
• Check the selected input/output devices
• Try restarting the app

Build Errors

If you encounter build errors:

1. Clean the iOS build:

   cd ios
   rm -rf Pods Podfile.lock
   pod install
   cd ..

2. Clear Metro bundler cache:

   npx expo start --clear

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Author

LiveVox

Support

For issues and questions, please open an issue on GitHub.