Topic frequency

[deneland]

This is a great tool - greatly helps our debugging!

It would be nice to be able to specify a logging frequency. We also record image data, but do not need the full original framerate. It would be great if it was possible to specify a frequency at which you want to record specific topics.

e.g.

            <!-- - test1                # Inherit defaults
            - test2:               
                duration: 2
                frequency: -1 #Original frequency
            - test3:               
                duration: -1       
                frequency: 2 # Only write messages to rosbag at 2 Hz
                memory: 0.00 -->

[CallumJHays]

You may be able to achieve the same result using http://wiki.ros.org/topic_tools/throttle and instead record the topic_throttled topic. Not sure what performance implications this has.

Would still be nice if rosbag_snapshot supported this natively.