AttributeError: '_sensor_msgs__CameraInfo' object has no attribute 'encoding'

edit

I want to save image from a bag file.And I have fellow the example, but I will always get a error like this:

http://library.isr.ist.utl.pt/docs/ro...

Traceback (most recent call last): 
File "image.py", line 55, in main() File "image.py", line 50, in main readImage(topic_name) File "image.py", line 31, in readImage cv_image = CvBridge().imgmsg_to_cv2(msg, "32FC1") File "/opt/ros/kinetic/lib/python2.7/dist-packages/cv_bridge/core.py", line 163, in imgmsg_to_cv2 dtype, n_channels = self.encoding_to_dtype_with_channels(img_msg.encoding) AttributeError: '_sensor_msgs__CameraInfo' object has no attribute 'encoding'

Ros version:

ROS Kinetic Kame

And the cv_bridge is in the path:

/opt/ros/kinetic/lib/python2.7/dist-packages/cv_bridge/__init__.pyc
/opt/ros/kinetic/lib/python2.7/dist-packages/rosbag/__init__.pyc
/opt/ros/kinetic/lib/python2.7/dist-packages/cv2.so

I print out the attr of the "msg"

['__class__', '__delattr__', '__doc__', '__eq__', '__format__', '__getattribute__', '__getstate__', '__hash__', '__init__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setstate__', '__sizeof__', '__slots__', '__str__', '__subclasshook__', '_check_types', '_connection_header', '_full_text', '_get_types', '_has_header', '_md5sum', '_slot_types', '_spec', '_type', 'data', 'deserialize', 'deserialize_numpy', 'encoding', 'header', 'height', 'is_bigendian', 'serialize', 'serialize_numpy', 'step', 'width']

By the way I get this error too:

Unrecognized image encoding [yuyv]

my code:

def readImage(topic_name):  
    bag  = rosbag.Bag('2018-11-20-15-54-07.bag') 

    bridge = CvBridge()

    for topic, msg, t in bag.read_messages(topics=topic_name):
        try:
            print dir(msg)
            cv_image = CvBridge().imgmsg_to_cv2(msg, "32FC1")
        timestr = "%.6f" %  msg.header.stamp.to_sec()
            image_name = timestr+ ".jpg"
        cv2.imwrite(image_name, cv_image)
        except CvBridgeError as e:
            print e

Any ideas ! thanks a lot