Domesday Duplicator (DdD) - Command Line Version

Command Line Capture Control

This document describes the new command line options added to DomesdayDuplicator for controlling capture operations without GUI interaction.

New Command Line Options

--start-capture

Automatically starts capture when the application launches.

Requirements:

• USB capture device must be connected and detected
• All capture settings (output directory, format, etc.) are configured via GUI preferences
• Advanced naming settings are used for file naming

Usage:

./DomesdayDuplicator --start-capture

--headless

Runs the application without showing the GUI window. Must be used together with --start-capture.

Usage:

./DomesdayDuplicator --start-capture --headless

--stop-capture

Stops any currently running capture and exits the application.

Usage:

./DomesdayDuplicator --stop-capture

--output-file

Specifies a custom output filename (without extension) or full path for the capture.

Features:

• Accepts relative filenames (saved to configured capture directory)
• Accepts absolute paths (saved to specified location)
• Extension is automatically added based on capture format (.lds, .raw, or .cds)
• Overrides Advanced Naming dialog settings when specified

Usage:

# Relative filename (saved to configured capture directory)
./DomesdayDuplicator --start-capture --output-file my_vhs_capture

# Absolute path (saved to specified location)
./DomesdayDuplicator --start-capture --output-file /run/media/user/2TB/Captures/my_vhs_capture

--debug (-d)

Shows debug information (existing option, included for completeness).

Usage:

./DomesdayDuplicator --debug --start-capture

Use Cases

Automated Capture Scripts

The new command line options enable script-based capture automation:

#!/bin/bash
# Start capture in headless mode
./DomesdayDuplicator --start-capture --headless &
CAPTURE_PID=$!

# Wait for some condition or time
sleep 3600  # Capture for 1 hour

# Stop the capture
./DomesdayDuplicator --stop-capture

Remote Control Integration

You can now trigger capture start/stop from external scripts without needing GUI automation tools like pyautogui.

Scheduled Captures

Combined with cron or systemd timers, you can schedule automatic captures:

# Start capture at 2 AM daily
0 2 * * * /path/to/DomesdayDuplicator --start-capture --headless

Configuration

All capture settings (output directory, format, USB device, etc.) must be configured through the GUI preferences before using command line capture. The command line options use whatever settings are currently saved in the configuration.

Error Handling

The application will exit with appropriate error codes:

• 0: Success
• 1: Invalid command line options
• 1: USB device not found or not ready (with --start-capture)

Error messages are logged to stderr and can be captured in scripts.

Compatibility

• All existing GUI functionality is preserved
• The application can still be used normally through the GUI
• Command line options are completely optional
• Works on Linux, Windows, and macOS (wherever the original application runs)

Technical Details

• Uses Qt's QCommandLineParser for robust option handling
• Integrates with existing capture logic (StartCapture/StopCapture methods)
• Preserves all existing signal/slot architecture
• Thread-safe implementation using existing atomic variables
• No changes to capture file formats or metadata generation

The Decode Family

The samples the DdD capture can be used with the family of decoders that make the FM RF Archival workflow ready to use today.

LaserDisc Decode / VHS-Decode (Videotape) / CVBS (Composite) Decode / HiFi Decode / RTLSDR HiFi Decode / MUSE-Decode / CD-Decode / FL2K TBC Player

3D Printed Case

The DomesDay Duplicator also has a 3D models and ready to use data for producing 3D printed cases, to protect from dust or line with copper tape for affordable EMI shielding for example.

Authors

Domesday Duplicator was written & designed by Simon Inns.

Current documentation & fabrication is maintained by Harry Munday.

Licences

• Software License - (Creative Commons BY-SA 4.0)
• Hardware License - (GPLv3)