问不能同时连接6个以上的IP摄像头

EN

import cv2
import threading


class camThread(threading.Thread):
    def __init__(self, previewName, camID):
        threading.Thread.__init__(self)
        self.previewName = previewName
        self.camID = camID
    def run(self):
        print("Starting " + self.previewName)
        camPreview(self.previewName, self.camID)


def camPreview(previewName, camID):
    cv2.namedWindow(previewName)
    cam = cv2.VideoCapture(camID)
    if cam.isOpened():
        rval, frame = cam.read()
    else:
        rval = False

    while rval:
        cv2.imshow(previewName, frame)
        rval, frame = cam.read()
        key = cv2.waitKey(20)

        if key == 27:
            break
    cv2.destroyWindow(previewName)

 thread = camThread('Cam', 'rtsp://admin:pass@1.2.3.4/axis-media/media.amp?videocodec=h264&resolution=320x240'')
 thread.start()

class VideoCamera(threading.Thread):
def __init__(self, cam_ip):
    threading.Thread.__init__(self)
    self.cam_ip_str = str(cam_ip)
    url = 'rtsp://admin:pass@' + self.cam_ip_str + '/axis-media/media.amp?videocodec=h264&resolution=320x240'
    self.video = cv2.VideoCapture(url)
    print("Starting " + self.cam_ip_str)

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

def get_frame(self):
    ret, 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')

def cam_index(request, cam_name):
    camera = Cameras.objects.get(camera_name = cam_name)
    video_thread = gen(VideoCamera(cam_ip=camera.IP_adress))
    stream = StreamingHttpResponse(video_thread, content_type="multipart/x- mixed-replace;boundary=frame")
    return stream