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Recording (MCAP)

Conduit can write every topic it publishes to an MCAP file on the device. Open the file in Foxglove or Lichtblick, or replay it into a ROS 2 graph with ros2 bag play. Recording is free.

Record

Next to the Start button, pick what Start does:

Mode What happens
Publish Sends the topics to ROS 2. Nothing is recorded
Record Writes the topics to an MCAP file. No network or ROS 2 host is needed
Both Sends the topics to ROS 2 and records them

Turn on the sensors you want, then tap Start. Tap it again to stop and close the file.

A recording holds the same messages, with the same stamps, as the live topics, plus /tf_static, so viewers can place point clouds and camera images in 3D. Each file carries the message definitions it uses, so it opens without your .msg files.

Find your recordings

Tap the folder button next to Settings. The list shows each recording's file name, size and date, and the total size at the top. Swipe a recording to delete it.

Files are named conduit_<yyyy-MM-dd>_<HH-mm-ss>.mcap, in the device's local time.

Share a recording

Sharing a recording off the device needs the Recording Export purchase (Settings → Premium Features). With it:

  • The share button on a recording opens the share sheet: AirDrop, Files, Mail and so on.
  • Recordings are kept in Documents/Recordings, which the Files app (iPhone and iPad) and Finder (Mac, with the iPhone connected) can open. Recordings made before the purchase move there too.

Without it, recordings stay in Conduit's private storage and the share button shows a lock.

Open a recording

Foxglove or Lichtblick: open the .mcap file. The file is indexed, so the timeline and seeking work right away.

ros2 bag: Jazzy, Kilted, Lyrical and Rolling read MCAP out of the box. Humble needs the MCAP storage plugin first.

# Humble only
sudo apt install ros-humble-rosbag2-storage-mcap

ros2 bag info conduit_2026-11-05_09-30-00.mcap
ros2 bag play conduit_2026-11-05_09-30-00.mcap

audio_common_msgs/AudioData and point_cloud_interfaces/CompressedPointCloud2 are not in a default ROS 2 install. To play those topics back into ROS 2, install the packages that define them (see the FAQ for audio_common_msgs), or choose the topics to play with ros2 bag play --topics.

Tips

  • Camera and LiDAR fill the device quickly. Lower the camera resolution or rate in the sensor's settings for long recordings.
  • In the background, camera and LiDAR stop (an iOS restriction), so they leave a gap in the recording.
  • See the FAQ for more.