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ROS 2 Recording and Playback Tool (Bag2)

1. Introduction​

ros2 bag (Bag2) is the official ROS 2 tool for recording and replaying topic data. It allows developers to:

  • Record live topic data\
  • Replay recorded data without restarting original nodes\
  • Debug issues repeatedly using the same dataset\
  • Share captured data with teammates

2. Start a Topic Node to Record​

For example, start the built-in ROS 2 talker demo:

ros2 run demo_nodes_py talker

3. Recording​

/topic-name refers to the topic you want to record.

# Record a single topic
ros2 bag record /topic-name

# Record multiple topics
ros2 bag record topic-name1 topic-name2

# Record all topics
ros2 bag record -a

Recording Options​

  • -o <name> --- Customize the output file name
ros2 bag record -o file-name topic-name
  • -s <storage> --- Storage format
    By default, sqlite3 is used.

4. Viewing Recorded Topic Information​

Before playback, inspect the bag file to view:

  • Recording duration\
  • File size\
  • Topic types\
  • Number of messages
ros2 bag info rosbag2_2023_10_31-07_58_23

5. Example --- Recording All Topics​

ros2 bag record -a

Recording All Topics

To stop recording, press Ctrl + C.

After stopping, a folder like this will be created:

rosbag2_2023_10_31-08_21_21

Recorded Bag Folder

6. Playback​

Replay recorded data using:

ros2 bag play rosbag2_2023_10_31-07_58_23

7. Viewing During Playback​

View replayed topic data:

ros2 topic echo /chatter

8. Playback Options​

8.1 Play at Different Speeds​

The -r option modifies playback speed.

ros2 bag play rosbag2_2023_10_31-07_58_23 -r 10

8.2 Loop Playback​

ros2 bag play rosbag2_2023_10_31-07_58_23 -l

8.3 Play a Single Topic​

ros2 bag play rosbag2_2023_10_31-07_58_23 --topics /chatter

9. Example --- Playback and Viewing​

9.1 Playback​

ros2 bag play rosbag2_2023_10_31-07_58_23 -l

9.2 View Output​

ros2 topic echo /chatter

Playback Topic Output

This documentation is maintained by HemiHex for ROS 2 data recording and playback workflows.