Audio-over-RDP File Teleport

A Python CLI application for transmitting files as audio signals over RDP connections. This system allows you to transfer files from a remote Windows 11 host (via RDP) to a local Windows 11 machine using audio signals.

Features

• Audio-over-RDP Transmission: Transmits files as audio signals that can be captured via WASAPI loopback
• Robust MFSK Modulation: Uses Multiple Frequency Shift Keying with configurable rates
• Forward Error Correction: Reed-Solomon FEC with interleaving for error resilience
• File Chunking: Supports large files by splitting them into manageable chunks
• WASAPI Loopback: Captures audio from RDP sessions without over-the-air transmission

Installation

Prerequisites

• Windows 11 (both host and local machine)
• Python 3.8 or higher
• Audio devices with WASAPI support

Install Dependencies

# Install Python dependencies
pip install -r requirements.txt

Usage

List Audio Devices

python -m teleport list

Transmit File (on remote host via RDP)

# Basic transmission
python -m teleport tx "path/to/file.txt"

# Advanced options
python -m teleport tx "path/to/file.txt" --rate fast --repeat 2 --device 0

Transmit Options:

• --rate: Transmission rate (safe, default, fast)
• --repeat: Number of times to repeat transmission
• --tone-start: Starting tone frequency in Hz (default: 1200)
• --tone-step: Tone step frequency in Hz (default: 120)
• --device: Audio device index (use list command to find)

Receive File (on local machine)

# Basic reception
python -m teleport rx "output_directory"

# Advanced options
python -m teleport rx "output_directory" --device 1 --timeout 300

Receive Options:

• --device: Audio device index for loopback capture
• --timeout: Receive timeout in seconds (default: 300)

Transmission Rates

Rate	Tones	Symbol Rate	Throughput	Use Case
safe	8	800 sps	~2.4 kbps	Poor audio quality
default	16	1000 sps	~4 kbps	Balanced performance
fast	32	1600 sps	~8 kbps	Good audio quality

How It Works

1. File Preparation: File is split into chunks with metadata headers
2. FEC Encoding: Reed-Solomon error correction and interleaving applied
3. Framing: Data is organized into frames with CRC32 checksums
4. MFSK Modulation: Digital data converted to audio tones
5. Audio Transmission: Tones played through speakers (RDP redirects to local)
6. Audio Reception: WASAPI loopback captures the audio signal
7. Demodulation: Audio tones converted back to digital data
8. FEC Decoding: Error correction and deinterleaving applied
9. File Reassembly: Chunks reassembled into original file

Audio Device Setup

For Transmission (Remote Host)

• Use default audio output device
• RDP will redirect audio to local machine
• No special setup required

For Reception (Local Machine)

• Use WASAPI loopback device
• Look for "Speakers (Remote Audio)" or similar
• Use python -m teleport list to find available devices

Troubleshooting

Common Issues

1. No Audio Devices Found

   • Ensure audio drivers are installed
   • Check Windows audio settings
   • Try running as administrator

2. Poor Reception Quality

   • Use safe rate for better reliability
   • Increase --repeat for redundancy
   • Check audio levels and device selection

3. File Transfer Fails

   • Verify file size (very large files may timeout)
   • Check audio device selection
   • Ensure stable RDP connection

Testing

Run the test suite to verify functionality:

python test_teleport.py

Technical Details

Audio Parameters

• Sample Rate: 48 kHz
• Channels: Mono
• Format: 32-bit float

Modulation

• MFSK (Multiple Frequency Shift Keying)
• Tone spacing: 120 Hz
• Frequency range: 900-4500 Hz
• Raised cosine windowing

Error Correction

• Reed-Solomon (255, 223) code
• Interleaving depth: 8
• CRC32 frame checksums

File Format

• Chunk size: 64 KB
• File header with metadata
• SHA-256 integrity verification

Limitations

• Requires stable RDP connection
• Audio quality affects transmission reliability
• Large files may take significant time
• Not suitable for real-time applications

License

This project is provided as-is for educational and experimental purposes.