AhmedBhati
commented
4 years ago Performance wise i found websockets faster and better than http when using multiple clients because for every request there would a three way handshake in http whereas it only in the start in websocket.
If you want to see the difference I have added a repository in which I have used http as the protocol, i have attached a demo video of the output there. So you can compare between the either
# app.py
import base64
import time
import cv2
from time import sleep
from flask import Flask, render_template, request
from flask_socketio import SocketIO, emit
import eventlet
eventlet.monkey_patch()
app = Flask(__name__)
socketio = SocketIO(app, logger=True, async_mode='eventlet')
@socketio.on('connect', namespace='/web')
def connect_web():
print('[INFO] Web client connected: {}'.format(request.sid))
@socketio.on('disconnect', namespace='/web')
def disconnect_web():
print('[INFO] Web client disconnected: {}'.format(request.sid))
@socketio.on('connect', namespace='/local')
def connect_cv():
print('[INFO] CV client connected: {}'.format(request.sid))
@socketio.on('disconnect', namespace='/local')
def disconnect_cv():
print('[INFO] CV client disconnected: {}'.format(request.sid))
@app.route('/')
def index():
return render_template('index.html', async_mode=socketio.async_mode)
@socketio.on('stream_request')
def stream_video(message):
socketio.emit('stream_response', message, namespace='/web', broadcast=True)
if __name__ == '__main__':
socketio.run(app,host="127.0.0.1", port=5000)# camera.py
import datetime
from threading import Thread
import base64
import time
import cv2
import socketio
sio = socketio.Client(logger=True)
@sio.event
def connect():
print('[INFO] Successfully connected to server')
@sio.event
def connect_error():
print('[INFO] Failed to connect to server.')
@sio.event
def disconnect():
print('[INFO] Disconnected from server.')
def encode_image(image):
image = cv2.imencode('.jpg', image)[1].tobytes()
image = base64.b64encode(image).decode('utf-8')
image = f"data:image/jpeg;base64,{image}"
return image
class FPS:
def __init__(self):
# store the start time, end time and total number of frames
# that were examined between the start and end intervals
self._start = None
self._end = None
self._numFrames = 0
def start(self):
# start the timer
self._start = datetime.datetime.now()
return self
def stop(self):
# stop the timer
self._end = datetime.datetime.now()
def update(self):
# increment the total number of frames examined during the
# start and end intervals
self._numFrames += 1
def elapsed(self):
# return the total number of seconds between the start and
# end interval
return (self._end - self._start).total_seconds()
def fps(self):
# compute the (approximate) frames per second
return self._numFrames / self.elapsed()
class WebCamVideoStream:
def __init__(self, src=0):
# initialize the video camera stream and read the first frame
# from the stream
self.stream = cv2.VideoCapture(src)
(self.grabbed, self.frame) = self.stream.read()
# initialize the variable used to inidicate if the thread
# should be stopped
self.stopped = False
def start(self):
# start the thread to read frames from the video stream
Thread(target=self.update, args=()).start()
return self
def update(self):
# keep looping infinitely until the thread is stopped
while True:
# if the thread indicator variable is set, stop the thread
if self.stopped:
return
# otherwise read the next frame from the stream
(self.grabbed, self.frame) = self.stream.read()
def read(self):
# return the frame most recently read
return self.frame
def stop(self):
# indicate that the thread should be stopped
self.stopped = True
def main():
# SLOW VERSION
cap = cv2.VideoCapture(0)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH, 600)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 600)
# stream = WebCamVideoStream(src=0).start()
i = 0
while True:
ret, frame = cap.read()
#frame = stream.read()
frame = cv2.resize(frame, (320,280))
sio.emit('stream_request', {'image': encode_image(frame)})
#stream.stop()
cap.release()
#cv2.destroyAllWindows()
if __name__ == "__main__":
sio.connect('http://127.0.0.1:5000',namespaces=['/local'])
main()
whikwon
Zarvoira
slowpoison752
miguelgrinberg
Dear Miguel:
Hello
This is from your video streaming page + emit , server side (i removed the Return):
here the problems are Response and the Generator mixing with the event-driven SocketIO
client
html
<img id="image" src="video_feed">Would you please help me ? i know something is wrong here but i cant't figure it
Thanks a million for your great work