MaYaRa Radar Playback Plugin for SignalK

A SignalK plugin for playing back .mrr radar recordings through the SignalK Radar API.

What This Plugin Does

This plugin allows you to play pre-recorded radar data (.mrr files) through SignalK's Radar API. During playback, the recording appears as a virtual radar that any SignalK radar consumer can connect to and display.

Use cases:

• Test and develop SignalK radar display applications without live radar hardware
• Demo radar functionality at exhibitions or presentations
• Debug radar rendering code with consistent, repeatable data
• Share interesting radar captures with other developers

Installation

Install from the SignalK App Store:

1. Open your SignalK server web interface
2. Go to Appstore > Available
3. Search for "MaYaRa Radar Playback"
4. Click Install
5. Restart SignalK when prompted

Getting Started

1. Access the Playback Interface

After installation, navigate to:

http://your-signalk-server:3000/plugins/@marineyachtradar/signalk-playback-plugin/playback.html

Or find it in SignalK's Webapps menu.

2. Upload a Recording

You can upload .mrr or .mrr.gz files:

• Drag and drop a file onto the upload zone
• Or click the upload zone to browse for a file

Recordings are stored on the SignalK server and persist across restarts.

3. Load and Play

1. Select a recording from the list
2. Click Load to prepare it for playback
3. Click Play to start playback
4. Use Pause and Stop as needed
5. Enable Loop to repeat the recording continuously

4. View the Radar

Click View Radar to open the radar display. This shows the playback radar using the built-in viewer.

Viewing with Other Clients

During playback, the recording registers as a virtual radar in SignalK. The radar ID follows the pattern playback-{filename}.

Using mayara-server-signalk-plugin

If you have the mayara-server-signalk-plugin installed (the main MaYaRa radar plugin), you can also view playback recordings through its interface:

1. Start playback in this plugin
2. Open the mayara-server-signalk-plugin's radar viewer
3. The playback radar will appear in the radar list
4. Select it to view the recording with full MaYaRa GUI features

Using Other SignalK Radar Consumers

Any application that implements the SignalK Radar API can display the playback:

• The radar appears at /signalk/v2/api/vessels/self/radars/playback-{filename}
• Spoke data streams via SignalK's binary WebSocket

Obtaining Recording Files

Recording files (.mrr) are created by mayara-server when connected to a live radar:

1. Run mayara-server with a radar connected
2. Open the recordings page at http://localhost:6502/recordings.html
3. Select a radar and click Start Recording
4. Click Stop Recording when done
5. Download the recording as .mrr.gz (compressed)
6. Upload to this SignalK plugin

File Format

• .mrr - MaYaRa Radar Recording (uncompressed)
• .mrr.gz - Gzip-compressed recording (~95% smaller for transfer)

Both formats are supported for upload. Files are stored uncompressed on the server for fast playback.

Troubleshooting

Recording won't load:

• Check the SignalK server logs for errors
• Ensure the file is a valid .mrr or .mrr.gz file
• Verify the file wasn't corrupted during transfer

No radar appears in SignalK:

• Make sure playback is started (not just loaded)
• Refresh the radar consumer application
• Check that SignalK's Radar API is enabled

Playback stutters:

• This can happen on slower systems with large recordings
• Try using recordings with fewer spokes per revolution

Technical Details

This plugin:

• Reads .mrr files directly (no mayara-server required)
• Registers as a RadarProvider via SignalK's Radar API
• Emits spoke frames through SignalK's binaryStreamManager
• Plays back frames at their original recorded timing
• Sets power status to "transmit" so GUI shows radar as active (not STANDBY)
• Pre-loads all frames for accurate timing
• Auto-stops current playback when loading a different file

Development

After cloning, install dependencies and build the GUI:

npm install
npm run build

To use a local mayara-gui checkout (sibling directory) instead of npm:

npm run build -- --local-gui

Note: The public/ directory is gitignored but included in the npm tarball. It's built automatically during npm publish via prepublishOnly.

Related Projects

• mayara-server - Standalone radar server (creates recordings)
• mayara-server-signalk-plugin - SignalK plugin for live radar (connects to mayara-server)

License

MIT License - See LICENSE for details.