[ROS2] The Image frame rate half of the CameraInfo frame rate

[b4795]

Steps to reproduce:

Publish Image and CameraInfo using CameraPublisher.

Observed & Expected:

Image frame rate (as measured by ros2 topic hz) is around 8. Expected: equal to the CameraInfo frame rate.
CameraInfo frame rate (as measured by ros2 topic hz) is around 16. Expected: equal to the Image frame rate.

Questions:

Could it be that any other Image fails to be published?
Could it be an issue with ros2 topic hz?

[EwingKang]

I've also encountered this issue. Check this issue: ros2/ros2cli#871
I workaround it by modifying the QoS setting directly in the installed location /opt/ros/iron/lib/python3.10/site-packages/ros2topic/verb/hz.py. By changing the qos profile line to rclpy.qos.qos_profile_parameters, it is possible for ros2 topic hz to report correct frequency.