Image publisher gives numpy error

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Hi, I am running the code from the directory of the file. After initiating both the publisher and subscriber the code works perfectly for 15sec and then give the error shown bellow.

Code:

#!/usr/bin/env python 
import cv2
import rospy
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError

def read_video():
  video_publisher = rospy.Publisher("tennis_ball_image", Image, queue_size=100)
  video_capture = cv2.VideoCapture("video/tennis-ball-video.mp4")
  while not rospy.is_shutdown():
    _,rgb_frame = video_capture.read()
    ros_image = CvBridge().cv2_to_imgmsg(rgb_frame, "bgr8")
    video_publisher.publish(ros_image)
    cv2.waitKey(10)
  video_capture.release()   

if __name__ == '__main__':

 try:
     rospy.init_node("tennis_ball_publisher", anonymous=True)
     read_video()
     rospy.spin()
 except rospy.ROSInterruptException:
     rospy.loginfo("node terminated.")

Error:

Traceback (most recent call last):
  File "./image_publisher_node.py", line 21, in <module>
    read_video()
  File "./image_publisher_node.py", line 12, in read_video
    ros_image = CvBridge().cv2_to_imgmsg(rgb_frame, "bgr8")
  File "/opt/ros/melodic/lib/python2.7/dist-packages/cv_bridge/core.py", line 246, in cv2_to_imgmsg
    raise TypeError('Your input type is not a numpy array')
TypeError: Your input type is not a numpy array