Replace fragment of .bag file

edit

Hi, I've got a recorded bag and I need to modify the numerical values of exactly one line that looks like this:

/robot/imu_angle_estimator/hard_iron=[[-0.0460591580529], [8.788953e-14], [-0.0179491346075]]

I've tried to solve this by editing the bag file but then the bag gets corrupted and I can't use it anymore, even after applying "$ rosbag reindex ...". I've tried to use rosbag filter but with no success. This line appears at the beginning of the bag file, only once.

Maybe this is a very basic question but I haven't been able to find a solution. Every bit of help is apprecciated.

Thank you in advance.