如何使用Opencv和Flask將Webcam Image流廣播到多個設備？

Question

我有以下代碼。 嘗試將一台設備連接到服務器時，它可以正常工作。 當兩個設備連接時，只有一個設備工作，另一個凍結，並出現以下錯誤。

目標是將視頻流廣播到多個設備。 另外，有沒有辦法通過Flask改善傳輸的FPS並減少延遲？

碼

Camera.py

import cv2

class VideoCamera(object):
    def __init__(self):
        # Using OpenCV to capture from device 0. If you have trouble capturing
        # from a webcam, comment the line below out and use a video file
        # instead.
        self.video = cv2.VideoCapture(0)
        # If you decide to use video.mp4, you must have this file in the folder
        # as the main.py.
        # self.video = cv2.VideoCapture('video.mp4')

    def __del__(self):
        self.video.release()

    def get_frame(self):
        success, image = self.video.read()
        # We are using Motion JPEG, but OpenCV defaults to capture raw images,
        # so we must encode it into JPEG in order to correctly display the
        # video stream.
        ret, jpeg = cv2.imencode('.jpg', image)
        return jpeg.tobytes()

Main.py

import os

install_opencv = os.system("pip install flask opencv-python")
print("Install OPENCV-PYTHON: ", install_opencv)


from flask import Flask, render_template, Response
from camera import VideoCamera

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

def gen(camera):
    while True:
        frame = camera.get_frame()
        yield (b'--frame\r\n'
               b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n\r\n')

@app.route('/video_feed')
def video_feed():
    return Response(gen(VideoCamera()),
                    mimetype='multipart/x-mixed-replace; boundary=frame')

if __name__ == '__main__':
    app.run(host='0.0.0.0', debug=True)

錯誤

Traceback (most recent call last):
cv2.error: OpenCV(3.4.3) C:\projects\opencv-python\opencv\modules\imgcodecs\src\grfmt_base.cpp:145: error: (-10:Unknown error code -10) Raw image encoder error: Empty JPEG image (DNL not supported) in function 'cv::BaseImageEncoder::throwOnEror'
127.0.0.1 - - [01/Nov/2018 16:16:21] "GET /video_feed HTTP/1.1" 200

Answer 1

我也這樣做了，無法訪問和兩個設備。 在github上有一個項目https://github.com/miguelgrinberg/flask-video-streaming或者你可以在開發者的網站上看到更好的解釋https://blog.miguelgrinberg.com/post/flask-video-streaming-重訪 #commentform

使用此代碼，我可以從多個設備訪問，但只允許顯示相機。 我正在工作，以便可以查看2個或更多相機，就好像它是DVR一樣。