FreeCaster - AirPlay VST3 Plugin

A cross-platform VST3 plugin that streams real-time audio from your DAW to AirPlay-enabled speakers and devices, similar to Audiomovers AirCaster.

Features

✅ Real-time audio streaming to AirPlay devices
✅ Automatic device discovery via mDNS/Bonjour
✅ Cross-platform support (macOS, Windows, Linux)
✅ Low-latency buffering
✅ Simple, intuitive GUI
✅ VST3 and Standalone formats

Platform Support

macOS

Native AirPlay integration via AVFoundation
Best audio quality and device compatibility
Supports AirPlay and AirPlay 2 devices

Windows

RAOP protocol implementation
Compatible with most AirPlay devices
Requires network with mDNS support

Linux

RAOP protocol implementation
Uses Avahi for device discovery
Full compatibility with AirPlay devices

Use Cases

Mix Checking: Preview your mixes on different speakers without bouncing
Remote Monitoring: Listen in another room while working
Consumer Testing: Hear how your mix sounds on consumer-grade speakers
Multi-Room: Stream different channels to different rooms
Client Playback: Send audio to client listening areas

Quick Start

Build the plugin (see instructions below)
Install the VST3 to your plugins folder
Load it in your DAW on your master track
Select an AirPlay device from the list
Click "Connect" and start playing

For detailed setup instructions, see USER_GUIDE.md.

Building

Requirements

CMake 3.15+
C++17 compiler
JUCE (automatically downloaded)
OpenSSL 3.0 or later (for RAOP authentication)

Quick Build

mkdir build && cd build
cmake ..
cmake --build . --config Release

Platform-Specific Notes

macOS:

Uses native AVFoundation for AirPlay
Automatically detected and configured
Requires macOS 10.13+

Windows/Linux:

RAOP protocol implementation
Requires OpenSSL for authentication
Ensure mDNS service is running (or Avahi on Linux)

Testing

The project includes comprehensive automated testing capabilities:

# Run automated AirPlay device discovery and connection testing
python3 automated_airplay_test.py

This script will:

Discover all AirPlay devices on your network
Attempt to connect to each device
Log detailed RTSP handshake information
Provide connection status summary

For more information on testing, see CURRENT_STATUS.md.

Architecture

The plugin uses a modular architecture with platform-specific implementations:

┌─────────────────────────────────────┐
│         VST3 Plugin (JUCE)          │
├─────────────────────────────────────┤
│        Plugin Processor             │
│      (Audio Processing)             │
├─────────────────────────────────────┤
│       AirPlay Manager               │
│    (Streaming Coordination)         │
├──────────┬──────────────────────────┤
│ macOS:   │ Windows/Linux:           │
│ Native   │ RAOP Protocol            │
│ AirPlay  │ Implementation           │
└──────────┴──────────────────────────┘
       │              │
       └──────┬───────┘
              │
       AirPlay Devices

Components

PluginProcessor: Main audio processing and VST3 interface
PluginEditor: GUI with device list and connection controls
AirPlayManager: Coordinates streaming and platform selection
DeviceDiscovery: mDNS device discovery across platforms
AudioEncoder: PCM/ALAC encoding for AirPlay
StreamBuffer: Thread-safe circular buffer for audio data
Platform Implementations:
- AirPlayMac: macOS native implementation
- AirPlayWindows: Windows RAOP client
- AirPlayLinux: Linux RAOP client

Technical Details

Audio Format: Stereo PCM 16-bit
Sample Rates: 44.1 kHz, 48 kHz
Latency: 200-500ms (network dependent)
Protocol: RAOP (Remote Audio Output Protocol)
Discovery: mDNS/Bonjour

Known Limitations

Stereo only (no multichannel/surround)
Network latency (~200-500ms) makes it unsuitable for tracking
Some AirPlay 2 advanced features not implemented
Authentication-required devices may not work
ALAC encoding not yet fully implemented (uses PCM)

Future Enhancements

Troubleshooting

No devices found

Ensure computer and devices are on same network
Check firewall settings
Verify mDNS/Bonjour is enabled

Connection failures

Restart AirPlay device
Check device compatibility
Disable VPN if active

Audio dropouts

Increase DAW buffer size
Use wired Ethernet connection
Check network bandwidth

See USER_GUIDE.md for more troubleshooting tips.

License

This project is provided as-is for educational and personal use.

Acknowledgments

Built with JUCE
Inspired by Audiomovers AirCaster (FreeCaster is a free, open-source alternative)
RAOP protocol information from various open-source projects

Contributing

Contributions welcome! Areas needing work:

ALAC encoder implementation
Enhanced device authentication
Improved cross-platform mDNS discovery
Additional audio format support
Better error handling

Disclaimer

This is an educational/reference implementation. AirPlay is a trademark of Apple Inc. This project is not affiliated with or endorsed by Apple Inc.

Skeyelab/FreeCaster