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rqt_bag supersedes rxbag, which is deprecated since ROS groovy.

Overview

rqt_bag is an application for recording and managing bag files. Primary features:

• show bag message contents
• display image messages (optionally as thumbnails on a timeline)
• plot configurable time-series of message values
• publish/record messages on selected topics to/from ROS
• export messages in a time range to a new bag

rqt_bag can be extended via a plugin mechanism. Core plugins are contained in the rqt_bag_plugins package available in the rqt_common_plugins metapackage.

Usage

To run

$ rqt

and select from Plugins --> Logging --> Bag.

Or simply the following (with this you can't open rqt_bag with other rqt tools).

$ rqt_bag

The main window shows a timeline representing the stream of messages contained in the bag file, listed by topic.

Publish ROS topics while playing back from the recorded bag file

Right-click on the name of the topic you want to publish, then select Publish (as in the image below).

Note: Don't forget to use simulation time when republishing from a bag file: Using Sim Time

To stop recording

You can stop recording by re-clicking the red circle button.

Description for GUI components

Timeline

The messages are shown at the timestamp stored in the bag file. This timestamp may differ from the message's Header timestamp (if any), e.g. rosbag record stores the time the message was received.

Right-clicking on the timeline opens a menu with options for opening detailed message views, choosing which topics to display thumbnails for, managing re-publishing of messages, and exporting a time range of messages to another bag.

A subset of the data can be selected by dragging the cursor over a range of time at the top of the timeline. This selection is used in any message view, such as plot view.

Toolbar

At the top of the timeline window is a toolbar for controlling the playhead and zooming the display:

From left to right, the buttons on the toolbars allow you to:

• record mode
• load file
• save currently selected region to a bag file
• move playhead to start of timeline
• rewind or slow playback
• play/pause
• fastforward or slow rewind
• move playhead to end of timeline
• zoom in
• zoom out
• reset zoom level to full bag
• toggle thumbnail display

Status Bar

At the bottom of the window is a status bar:

From left to right, these indicators display:

• progress for background tasks
• timestamp of playhead
• time in human readable form
• elapsed time in seconds from start of timeline
• current playback speed

Message Views

Message views display information about the message immediately preceding the position of the timeline playhead (the vertical red line.) The message datatype determines which message views are available.

For details on common message views such as images and plotting, see rqt_bag_plugins.

Every message view has a toolbar for stepping the playhead forward to the next message on the topic, back to the previous message, or to the first and last messages in the bag.

raw

Every topic has an option of displaying a raw view of the message. This displays the fields of the message in a tree view:

Also, the following keyboard shortcuts can be used:

Plugin API

rqt_bag currently has a proof-of-concept plugin API, which is used in the rqt_bag_plugins package.