CREATE LIVE STREAMING VIDEO CHAT APP WITHOUT VOICE USING CV2 MODULE OF PYTHON

4 min readJun 5, 2021

NETWORK SOCKET

* A network socket is a software structure within a network node of a computer network that serves as an endpoint for sending and receiving data across the network.

The structure and properties of a socket are defined by an application programming interface (API) for the networking architecture.

|| IMPLEMENTATION OF SOCKETS

In Standard Internet Protocols like TCP and UDP :

* socket address is the combination of
        socket address = ( IP address , port number)

|| CLIENT-SERVER MODEL

Server creates socket on startup
May serve several clients concurrently
A client should know the server IP and port

PRE-REQUITIES :

-> Install following modules in cmd ::* pip install OpenCV-python
* pip install sockets
* pip install pickle-mixin.
* pip install supyr-struct

|| PYTHON SERVER MODULE

Socket creation

SYNTAX : server_socket = socket.socket(socket.AF_INET , socket.SOCK_DGRAM)CODE :
server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
host_name  = socket.gethostname()
host_ip = socket.gethostbyname(host_name)
print('HOST IP:',host_ip)
port = 10050
socket_address = (host_ip,port)

2. Socket bind

SYNTAX : server_socket.bind((host_ip , port))CODE :
server_socket.bind(socket_address)

3. Socket listen

SYNTAX : server_socket.listen(5) #5 is backlogCODE :
server_socket.listen(5)
print("LISTENING AT:",socket_address)

4. Socket accept

SYNTAX : client_socket , addr = server_socket.accept()CODE : 
while True:
	client_socket,addr = server_socket.accept()
	print('GOT CONNECTION FROM:',addr)
	if client_socket:
		cap = cv2.VideoCapture(0)
		
		while(cap.isOpened()):
			ret,vdo = cap.read()
			vdo = imutils.resize(vdo,width=320)
			a = pickle.dumps(vdo)
			message = struct.pack("Q",len(a))+a
			client_socket.sendall(message)
			
			cv2.imshow('TRANSMITTING VIDEO',vdo)
			key = cv2.waitKey(1) & 0xFF
			if key ==ord('q'):
				client_socket.close()

5. Socket client

client_socket.recv() or client_socket.send() or client_socket.sendall()

6. Close client

client_socket.close

| VIDEO DATA TRANSMISSION : At Server Side ::

With Open CV get video frames of webcam
With PICKLE serialize frame to byte data
Pack each frame data using STRUCT module
Send data to client and display frame

FINAL SERVER CODE :

OUTPUT :

|| PYTHON CLIENT MODULE

Socket creation

SYNTAX : client_socket = socket.socket(socket.AF_INET , socket.SOCK_STREAM)CODE :
client_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
host_ip = '169.254.72.59' # paste your HOST IP
port = 10050

2. Socket connect

SYNTAX : client_socket.connect(( host_ip , port ))CODE : 
client_socket.connect((host_ip,port)) # tuple
data = b"" # Initialise data variable as a string , b - bytes# Payload size is defined with "Q" i.e.,unsigned long long integer that takes 8 bytes
payload_size = struct.calcsize("Q")

3. Socket receive

SYNTAX : packet = client_socket.recv(1024) #1024 is buffer sizeCODE :
while True:
	while len(data) < payload_size:
		
               # when we recieve packet we use 4k buffer
                packet = client_socket.recv(4*1024) 
		
                if not packet: break
		data+=packet
	
        # First 8 bytes contain size of packed msg so we use data           from 0 to payload_size(i.e., 8)
        packed_msg_size = data[:payload_size]
	
        # Rest of the data contains video so we set new data which we have to frame to display
        data = data[payload_size:]
	msg_size = struct.unpack("Q",packed_msg_size)[0]
	
	while len(data) < msg_size:
		data += client_socket.recv(4*1024)
	
        # We will get the packed msg size and run the while loop until we receive all data from the client socket for frame
        frame_data = data[:msg_size]
	data  = data[msg_size:]
	
        # Finally, frame data is recovered
        frame = pickle.loads(frame_data)
	
        cv2.imshow("RECEIVING VIDEO",frame)
	key = cv2.waitKey(1) & 0xFF
	if key  == ord('q'):  # q is used to quit the video
		break
                   client_socket.close()