'''

Example for how to receive live data and display live video (without gaze overlay) from glasses.

gstreamer 0.10 required in order to display live video.

Note: This example program is *only* tested with Python 2.7 on Ubuntu 12.04 LTS

and Ubuntu 14.04 LTS (running natively).

Team Tobii Notes:

- tested with Python 3.7 on Windows 10 and MSYS2 (64bit ver)

- connects to glasses on Wifi only

- see livestream_p3_readme.txt for additional notes

'''

import time

import socket

import threading

import signal

import sys

import gi

gi.require_version('Gst', '1.0')

from gi.repository import Gst, Gio

timeout = 1.0

running = True

GLASSES_IP = "192.168.71.50" # IPv4 address on wlan

PORT = 49152 #for UDP

# Keep-alive message content used to request live data and live video streams

KA_DATA_MSG = "{\"type\": \"live.data.unicast\", \"key\": \"some_GUID\", \"op\": \"start\"}"

KA_VIDEO_MSG = "{\"type\": \"live.video.unicast\", \"key\": \"some_other_GUID\", \"op\": \"start\"}"

# Gstreamer pipeline definition used to decode and display the live video stream

PIPELINE_DEF = "udpsrc name=src do-timestamp=true name=src blocksize=1316 close-socket=false buffer-size=5600 !" \

"d3dvideosink force-aspect-ratio=True"

# Create UDP socket

def mksock(peer):

return socket.socket(iptype, socket.SOCK_DGRAM)

# Callback function

def send_keepalive_msg(socket, msg, peer):

time.sleep(timeout)

def signal_handler(signal, frame):

stop_sending_msg()

sys.exit(0)

def stop_sending_msg():

global running

running = False

if __name__ == "__main__":

signal.signal(signal.SIGINT, signal_handler)

peer = (GLASSES_IP, PORT)

# Create socket which will send a keep alive message for the live data stream

data_socket = mksock(peer)

td = threading.Timer(0, send_keepalive_msg,

[data_socket, KA_DATA_MSG, peer])

td.start()

# Create socket which will send a keep alive message for the live video stream

video_socket = mksock(peer)

tv = threading.Timer(0, send_keepalive_msg,

[video_socket, KA_VIDEO_MSG, peer])

tv.start()

# Create gstreamer pipeline and connect live video socket to it

Gst.init(None)

pipeline = Gst.Pipeline.new()

try:

pipeline = Gst.parse_launch(PIPELINE_DEF)

except Exception as e:

print(e)

stop_sending_msg()

sys.exit(0)

# Get element by name

src = pipeline.get_by_name("src")

# create gsocket obj to pass the pipeline's udpsrc element property called socket

gsock = Gio.Socket.new_from_fd(video_socket.fileno())

src.set_property("socket", gsock)

pipeline.set_state(Gst.State.PLAYING)

while running:

# Read live data

data, address = data_socket.recvfrom(1024)

print(data.decode())

state_change_return, state, pending_state = pipeline.get_state(0)

if Gst.StateChangeReturn.FAILURE == state_change_return:

stop_sending_msg()