# Invisible

Welcome to Pupil Invisible developer docs!

# Recording Format

Pupil Invisible Companion stores its data files in pairs: Each data file has a corresponding timestamp file. This is required to correlate the different data source after-the-effect in Pupil Cloud or Pupil Player.

You can find details to the specification of the Pupil Invisible Companion app recording format in this document.

# Network API

Pupil Invisible Companion app uses the NDSI v4 protocol to publish its scene video and gaze data via the local network.

Pupil Invisible Monitor app makes use of this API to list the local devices, receive their scene video, and visualize the most recent gaze data.

Below you can find a full example that receives gaze data from all available Pupil Invisible Companion devices:

import time

# https://github.com/pupil-labs/pyndsi/tree/v1.0
import ndsi  # Main requirement

GAZE_TYPE = "gaze"  # Type of sensors that we are interested in
SENSORS = {}  # Will store connected sensors

def main():
    # Start auto-discovery of Pupil Invisible Companion devices
    network = ndsi.Network(formats={ndsi.DataFormat.V4}, callbacks=(on_network_event,))

        # Event loop, runs until interrupted
        while network.running:
            # Check for recently connected/disconnected devices
            if network.has_events:

            # Iterate over all connected devices
            for gaze_sensor in SENSORS.values():
                # Fetch recent sensor configuration changes,
                # required for pyndsi internals
                while gaze_sensor.has_notifications:

                # Fetch recent gaze data
                for gaze in gaze_sensor.fetch_data():
                    # Output: GazeValue(x, y, ts)
                    print(gaze_sensor, gaze)


    # Catch interruption and disconnect gracefully
    except (KeyboardInterrupt, SystemExit):

def on_network_event(network, event):
    # Handle gaze sensor attachment
    if event["subject"] == "attach" and event["sensor_type"] == GAZE_TYPE:
        # Create new sensor, start data streaming,
        # and request current configuration
        sensor = network.sensor(event["sensor_uuid"])
        sensor.set_control_value("streaming", True)

        # Save sensor s.t. we can fetch data from it in main()
        SENSORS[event["sensor_uuid"]] = sensor
        print(f"Added sensor {sensor}...")

    # Handle gaze sensor detachment
    if event["subject"] == "detach" and event["sensor_uuid"] in SENSORS:
        # Known sensor has disconnected, remove from list
        del SENSORS[event["sensor_uuid"]]
        print(f"Removed sensor {event['sensor_uuid']}...")

main()  # Execute example

# Pupil Invisible Monitor

This is a stand alone desktop app that connects to Pupil Invisible using the Network API over WiFi. You can use it to live stream scene video and gaze data from all connected Pupil Invisible(s) on the network.

Check out Pupil Invisible Monitor on Github.