SoundSync

A lightweight, low-latency C# WPF application that captures your system's audio and routes it to multiple hardware output devices simultaneously. Built entirely on the Windows Core Audio API (WASAPI) using the NAudio library.

demo.mp4

SoundSync-link-demo.mp4

✨ Features

• Multi-Endpoint Routing: Play a single audio source (like a YouTube video or Spotify or any audio source) through multiple headphones or speakers at the exact same time.
• Aggressive Latency Control: Implements a custom ring-buffer clearing strategy to combat hardware clock drift, ensuring secondary devices stay within ~10-30ms of real-time.
• Anti-Feedback Loop Protection: Automatically detects your default Windows playback device and prevents audio from being routed back into it, completely eliminating infinite echo loops.
• Dynamic Device Scanning: Easily refresh the device list to detect newly plugged-in USB or Bluetooth headphones without restarting the app.
• Modern UI: Built with Windows Presentation Foundation (WPF) featuring a sleek, dark-mode graphical interface.

⚙️ How it Works

The application uses WasapiLoopbackCapture to intercept the raw audio bytes flowing to your default Windows audio endpoint.

When the user clicks "Connect", the app initializes a separate WasapiOut stream for every selected hardware device in Shared Mode. As Windows fires DataAvailable events containing the live audio bytes, the application aggressively broadcasts those bytes into a BufferedWaveProvider attached to every selected output.

🚀 Getting Started

📥 Download & Installation (For Regular Users)

You do not need to install anything to use SoundSync!

1. Go to the Releases Page.
2. Download SoundSync-Portable.exe.
3. Double-click the file to run it. That's it!
4. If you face any issue, open the application with "Run as Administrator".

(Note: If you download the smaller SoundSync-Light.exe version, you must have the .NET 8.0 Desktop Runtime installed on your PC).

💻 Building from Source (For Developers)

1. Clone the repository:

   git clone https://github.com/sugumar247/SoundSync.git

2. Open SoundSync.slnx in Visual Studio 2022.
3. The project relies on the NAudio library. Visual Studio should restore this NuGet package automatically. If not, run:

   dotnet restore

4. Press F5 to compile and run the application.

🎧 Usage & "Perfect Sync" Tutorial

If you are trying to share a movie with a friend using two pairs of headphones, you will notice a slight ~30ms delay on the 2nd pair of headphones if you capture audio directly from the 1st pair.

To achieve 100.00% perfect synchronization with zero echoes, use the "Dummy Hardware" trick:

1. Look at your Windows sound settings and find an audio device you aren't currently using (e.g., an HDMI Monitor with no speakers, or a Virtual Audio Cable like VB-Audio Cable).
2. Set that silent device as your Default Windows Output. (Your computer will go silent).
3. Open SoundSync.
4. Check the boxes for Headphone 1 and Headphone 2 or more.
5. Click Connect.

The app will now capture the silent audio stream, duplicate it, and push it to both sets of headphones via the C# engine. Because they share the exact same routing path, their latency is identical and they are perfectly synchronized!

🛠️ Built With

• C# / .NET 8.0 - The core framework
• WPF - UI Framework
• NAudio - Audio and WASAPI interaction

🤝 Contributing

Contributions, issues, and feature requests are welcome!

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📝 License

Distributed under the MIT License. See LICENSE for more information.