Dash Multi-Page App with cv2.VideoCapture supported?

Dash Python
1

Hi!
Im relatively new to plotly dash and could use some guidance. I’m trying to make a multi-page app that has one of the pages showing the output from cv2.VideoCapture. I’ve researched and found a couple different posts regarding this issue although it doesnt appear to have been solved for multi-page apps.

Following the guidance of the documentation for multi-page urls and a previous post which works when its a single page app here i’ve created an initial app that looks like this:

app.py

import dash
from dash import Dash, html, dcc
import dash_bootstrap_components as dbc
from pages.pose import video_feed

app = Dash(__name__, use_pages=True, external_stylesheets=[dbc.themes.SPACELAB])

app.layout = html.Div([
    html.H1('Multi-page app with Dash Pages'),
    html.Div([
        html.Div(
            dcc.Link(f"{page['name']} - {page['path']}", href=page["relative_path"])
        ) for page in dash.page_registry.values()
    ]),
dash.page_container
])

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

cam.py

import dash
import dash_core_components as dcc
import dash_html_components as html

from flask import Flask, Response
import cv2

dash.register_page(__name__)
server = Flask(__name__)
app = dash.Dash(__name__, server=server)

layout = html.Div([
    html.H1("Webcam Test"),
    html.Img(src="/video_feed")
])

class VideoCamera(object):
    def __init__(self):
        self.video = cv2.VideoCapture(0)

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

    def get_frame(self):
        success, image = self.video.read()
        ret, jpeg = cv2.imencode('.jpg', image)
        return jpeg.tobytes()


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')


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

if __name__ == '__main__':
    app.run_server(debug=True)

calling python cam.py works as expected after changing layout= to app.layout= however the calling python app.py returns a screen with the empty html components and no video capture in the img component. Thanks in advance for your help.