ROS2 failed to read bagselection unkown exception

When I try to read the messages from a specific topic in matlab I got unkown exception. This specific bag is the only one that got that error. I am attaching the topics I got, all of them are good except for the "novatel_bottom/bestpos". I wonder if there is further information about this error.

[Jagadeesh Konakalla]

Hi Manuel,

Please reach out to us through the MathWorks Technical Support. We may need more information to help you out.

Thanks,

Jagadeesh K

[Karthik Reddy Vennapureddy]

Hi Manuel,

With ROS 2 dashing installation command line,when you play the same bag file in python using "ros2 bag play <bag_folder>" after registering these custom messages via "colcon build", and run "ros2 topic echo /novatel_bottom/bestpos" in other terminal, could you check if the following error occurs:

"terminate called after throwing an instance of 'eprosima::fastcdr::exception::NotEnoughMemoryException'

what(): Not enough memory in the buffer stream

Aborted"

The reason for this error is the message is not serialized correctly on the topic and is corrupted, you can try re-recording the bag file with ROS 2 command line environment, see if "ros2 topic echo /novatel_bottom/bestpos" is successfull and then try reading the messages in MATLAB. If you have further issues, please contact MathWorks Technical Support as suggested by Jagadeesh.

Thanks,

Karthik Reddy

Answer 1

[Karthik Reddy Vennapureddy]

Hi Manuel,

While recording the ROS 2 bag file, the message failed to serialize on a topic and is corrupted. This can be seen by playing the bag file in ROS 2 python command line using "ros2 bag play <bagFolder>" in one terminal. Open other terminal and do "ros2 topic echo /novatel_bottom/bestpos", you can see that a error below is thrown:

"terminate called after throwing an instance of 'eprosima::fastcdr::exception::NotEnoughMemoryException'

what(): Not enough memory in the buffer stream

Aborted".

Starting with R2022a, a meaninful error message is shown here as :"Unable to read the data recorded on topic <topic_name> because the bag file appears to be corrupt. Record this topic again to the bag file".

Thanks,

Karthik Reddy