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rqt_bag different topic position for the same timestamp

asked 2015-12-09 19:17:22 -0500

chrisb gravatar image

Hello,

I recognized that even if I overwrite a time stamp of a topic rqt_bag does not place it on the same position in the timeline. So I'm wondering what rqt_bag uses otherwise to place the marker for the time the topic was published.

Thanks in advance.

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answered 2015-12-09 20:40:19 -0500

ahendrix gravatar image

When recording, rosbag and rqt_bag use the time that the recording node received the message as the bag timestamp.

The bag timestamp is part of the bag file format; it is not related to any timestamp that might be in the header of your message. (not all messages have headers or timestamps).

If you want to rewrite the bag timestamps to match the header timestamps, you'll need to use the rosbag API to open the bag file, read the messages and update the timestamps on the topics you care about. This is the first example in the rosbag cookbook: http://wiki.ros.org/rosbag/Cookbook

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Asked: 2015-12-09 19:17:22 -0500

Seen: 602 times

Last updated: Dec 09 '15