import requests, numpy as np, cv2
r = requests.get("http://CAMERA-IP:81/stream", stream=True, timeout=5)
buf = b""
for chunk in r.iter_content(4096):
    buf += chunk
    a = buf.find(b"\xff\xd8"); b = buf.find(b"\xff\xd9")
    if a != -1 and b != -1 and b > a:
        img = cv2.imdecode(np.frombuffer(buf[a:b+2], np.uint8), cv2.IMREAD_COLOR)
        print("frame:", None if img is None else img.shape)
        break