OpenCV with virtual cameras

test.py

import cv2

# Replace 1 with whatever camera you want 
cap = cv2.VideoCapture(1)

if not cap.isOpened():
    print("Error: Could not open camera.")
    exit()

cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)

while True:
    ret, frame = cap.read()
    if not ret:
        print("Error: Could not read frame.")
        break

    cv2.imshow('Camera', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()