Renaming a topic inside a bag file

asked 2011-03-11 23:59:03 -0600

dlmypr
236 ●7 ●10 ●20

When we record a bag file for example X.bag and it contains the topic data /a_topic

Is there any way to rename the topics name inside the X.bag /a_topic to /b_topic?

Best regards..

edit retag flag offensive close merge delete

add a comment

18

answered 2015-04-16 14:34:18 -0600

Enrique

834 ●22 ●28 ●37

updated 2016-01-23 20:36:50 -0600

I know this is quite old, but there's also this option:

rosrun rosbag topic_renamer.py <in topic> <in bag> <out topic> <out bag>

Another option is to simply remap the topics when you use rosbag play. For example, if you have the topic /foo inside the bag, you can to this to rename it (when published) into /bar:

rosbag play file.bag /foo:=/bar

The leading '/' might not be needed.

edit flag offensive delete link

Comments

yes. very good! it's very convenient!

asimay_y ( 2016-06-07 04:34:22 -0600 )edit

This info is very good!

harderthan ( 2018-08-15 20:28:09 -0600 )edit

add a comment

9

answered 2011-03-15 19:06:26 -0600

Tim Field
191 ●2 ●4 ●4

I'd use the rosbag Python API:

from rosbag import Bag
with Bag('Y.bag', 'w') as Y:
    for topic, msg, t in Bag('X.bag'):
        Y.write('/b_topic' if topic == '/a_topic' else topic, msg, t)

edit flag offensive delete link

Comments

Awesome...saved me a bunch of time finding this. Though I do have one oddity as a result - the bag is now 2x the size. Anyone know why?

Daniel Stonier ( 2014-07-19 09:02:10 -0600 )edit

Every time you use rosbag Python API, and I think also rosbag filter, the output bag is uncompressed. You have to rosbag compress after that. I'd say that's what happened to you.

Enrique ( 2016-01-23 20:38:40 -0600 )edit

how can you actually replace a topic name by another? how could one change the code for that?

rubot ( 2018-07-25 14:40:04 -0600 )edit

1

Here is my code:

from rosbag import Bag
with Bag('Y.bag', 'w') as Y:
for topic, msg, t in Bag('X.bag'):
    if topic == '/a_topic':
        Y.write('/b_topic', msg, t)
    else:
        Y.write(topic, msg, t)

kentam ( 2018-10-31 18:00:37 -0600 )edit

add a comment

2

answered 2011-03-13 11:22:12 -0600

William

17335 ●101 ●182 ●262 http://wjwwood.io/

You might consider using the tf_remap node that comes with the tf package: http://www.ros.org/wiki/tf#Nodes

From the wiki:

tf_remap

tf_remap listens to the /tf_old topic and republishes transforms on the /tf topic. This is mainly used with out-of-date bag files that need their coordinate frame IDs updated. The typical operation for this node is to play the bag file with /tf:=/old_tf. The tf_remap node is run with a ~mappings parameter that describes the mapping of frame IDs from old to new.

edit flag offensive delete link

Comments

This will only work if @dlmpyr is trying to do stuff with /tf. If it's some other topic, tf_remap probably won't work.

Eric Perko ( 2011-03-13 15:37:06 -0600 )edit

add a comment

2

answered 2011-03-12 00:16:00 -0600

Eric Perko

8406 ●73 ●90 ●144 http://ericperko.com/

Not sure if rosbag filter can do it, but you should be able to rename the topics using the rosbag API. For an example that reads in data on the tf topic and then writes it back out, see rosbag cookbook. That should be a good example to get you started.

edit flag offensive delete link

Comments

Thank you for the response. I also couldn't find anything about the filter. I changed the topic names of openni_camera directly as another approach.

dlmypr ( 2011-03-12 03:32:31 -0600 )edit

add a comment

Renaming a topic inside a bag file

4 Answers

Comments

Comments

Comments

Comments

Question Tools

Stats

Related questions

Renaming a topic inside a bag file edit

4 Answers

Comments

Comments

Comments

Comments

Question Tools

Stats

Related questions

Renaming a topic inside a bag file