Audio Router

A Windows desktop application that allows you to route and duplicate audio from any application to any output device without changing Windows settings or application configurations.

Features

• ⚡ Ultra-Low Latency: Optimized for movie streaming and gaming with as low as 10-20ms latency
• 🔓 Admin Mode Support: Run with elevated privileges for better performance and priority
• 🎛️ Configurable Latency: Choose from Ultra Low, Low, Normal, or High stability modes
• Zero Configuration: Works without modifying Windows audio settings or application settings
• Flexible Audio Routing: Select any input device to capture from and route to any output device
• Application-Level Context: Track which application's audio you're routing
• Multiple Routes: Create multiple audio routes simultaneously
• Volume Control: Adjust volume independently for each route
• Real-Time Management: Routes are temporary and cleared when the application closes
• Auto-Discovery: Automatically detects running applications with active audio sessions and available devices
• Modern UI: Clean, intuitive interface similar to Windows Volume Mixer

How It Works

Audio Router uses WASAPI (Windows Audio Session API) Loopback Capture to:

1. Capture audio output from your selected input device (any playback device on your system)
2. Buffer and process the audio stream
3. Apply independent volume control
4. Forward it to your selected output device
5. Maintain all routes in real-time without modifying system settings

Requirements

• Windows 10 or Windows 11
• .NET 8.0 Runtime or SDK
• Administrator privileges recommended for best performance (optional - can run in normal mode)
  • Admin mode enables HIGH process priority
  • Better audio thread scheduling
  • Reduced audio dropouts

Installation

Option 1: Build from Source

1. Install .NET 8.0 SDK

2. Clone the repository:

git clone <repository-url>
cd AudioRouter

3. Build the project:

dotnet build AudioRouter.sln --configuration Release

4. Run the application:

dotnet run --project AudioRouter/AudioRouter.csproj

Option 2: Publish Standalone Executable

Create a standalone executable that doesn't require .NET runtime:

dotnet publish AudioRouter/AudioRouter.csproj -c Release -r win-x64 --self-contained

The executable will be in AudioRouter/bin/Release/net8.0-windows/win-x64/publish/

Usage

Creating an Audio Route

1. Launch the Application: Run AudioRouter.exe

2. Select Source Application:

   • The left panel shows all applications currently playing audio
   • Click on the application you want to route (this helps you track what you're routing)
   • Use "Refresh Applications" if your app isn't listed

3. Select Input Device (Capture From):

   • Choose which audio device to capture from
   • This is typically the device that's playing the audio you want to route
   • Defaults to your system's default playback device

4. Select Output Device (Route To):

   • Choose the target output device from the dropdown
   • This is where the audio will be duplicated/forwarded to

5. Select Latency Mode ⚡:

   • Ultra Low (~10-20ms): Best for movies, gaming, real-time streams
   • Low (~30-50ms): Good balance of latency and stability
   • Normal (~50-100ms): Stable for most use cases
   • High (~100-200ms): Maximum stability for problematic systems

6. Start Route:

   • Click "▶️ Start Audio Route"
   • The route appears in the "Active Routes" panel on the right

7. Adjust Volume (Optional):

   • Use the slider next to each active route to control its volume
   • Volume is independent from system volume and application volume

Admin Mode (Recommended for Best Performance)

• Check Status: Look for the "⚡ ADMIN MODE" badge in the top-right corner
• Enable Admin Mode: Click "🔓 Run as Admin" button if not already running as admin
• Benefits:
  • High process priority for better audio performance
  • Reduced audio dropouts and glitches
  • Better thread scheduling for real-time audio
  • Essential for ultra-low latency mode

Managing Routes

• View Active Routes: All active routes are displayed in the right panel
• Adjust Volume: Use the slider (🔊) for each route
• Stop a Route: Select a route and click "⏹️ Stop Selected Route"
• Refresh Lists: Click the refresh buttons to update applications or devices

Tips

• Routes are automatically stopped if:

  • The source application is closed
  • The target device is disconnected
  • An error occurs during routing

• All routes are cleared when you close Audio Router

• For best results, ensure your source application is actively playing audio when creating a route

Architecture

Core Components

AudioRouter/
├── Models/
│   ├── AudioSession.cs        # Represents an audio session (application)
│   ├── AudioDeviceInfo.cs     # Represents an audio output device
│   └── AudioRoute.cs           # Represents an active audio route
├── Services/
│   ├── AudioSessionManager.cs     # Discovers active audio sessions
│   ├── AudioDeviceEnumerator.cs   # Lists available output devices
│   ├── AudioRouterEngine.cs       # Captures and routes audio
│   └── RoutingManager.cs          # Manages multiple routes
├── Converters/
│   └── VolumeConverter.cs      # Converts volume between UI and model
└── MainWindow.xaml/cs          # Main UI

Technology Stack

• WPF (Windows Presentation Foundation): Modern UI framework
• NAudio: Audio processing library
  • WASAPI Loopback Capture: Captures audio from applications
  • WASAPI Out: Outputs audio to devices
  • Volume Sample Provider: Per-route volume control
• .NET 8.0: Latest .NET framework

Limitations

• Captures all audio from the selected input device (not per-application isolation)
• Cannot route audio from applications using exclusive mode
• Requires audio to be actively playing through the selected input device
• Small latency (~50ms) may be noticeable in some scenarios
• The application selection helps you track routes but doesn't filter audio by process

Troubleshooting

Application Not Showing in List

• Ensure the application is actively playing audio
• Click "Refresh Applications"
• Verify the application is using the default audio device

No Audio on Target Device

• Check that the source application is playing audio
• Verify the route shows 🟢 (active)
• Adjust the route's volume slider
• Ensure the target device is set as a playback device (not disabled)

Poor Audio Quality or Crackling

• Reduce buffer size (requires code modification)
• Close other audio-intensive applications
• Update your audio drivers

Route Automatically Stops

• The source application may have stopped playing audio
• The target device may have been disconnected
• Check the status bar for error messages

Advanced Configuration

Changing Buffer Duration

Edit AudioRouterEngine.cs line 67:

BufferDuration = TimeSpan.FromSeconds(2), // Increase for stability, decrease for lower latency

Changing WASAPI Latency

Edit AudioRouterEngine.cs line 79:

new WasapiOut(outputDevice, AudioClientShareMode.Shared, false, 50); // 50ms latency

Development

Project Structure

• Built with .NET 8.0 and C# 12
• Uses MVVM pattern for UI data binding
• Asynchronous audio processing with Task-based API
• Event-driven architecture for route management

Adding Features

To add new features, consider these extension points:

• Custom audio effects: Insert between BufferedWaveProvider and VolumeSampleProvider
• Per-application capture: Implement process-specific WASAPI capture
• Audio visualization: Subscribe to the DataAvailable event
• Presets/Profiles: Serialize AudioRoute objects

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

License

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

Acknowledgments

• NAudio - Excellent audio library for .NET
• Microsoft WASAPI documentation
• Windows Audio Session API (WASAPI)

Disclaimer

This software is provided as-is without any warranty. Use at your own risk. The authors are not responsible for any audio issues, system crashes, or other problems that may arise from using this software.