Data format

Capture side

Data uploaded to the platform or downloaded locally (mcap)

When you upload to the platform or download locally, the folder layout is as follows:

episode_000xx_yyyy_mm_dd_hh_mm_ss/
  - episode_id_yyyy_mm_dd_hh_mm_ss_trimmed_timestamp_mcap_0.mcap
  - metadata.yaml
  - device_meta.json
  - status/
    - sensor_camera1/
      - recorder.status
    - sensor_camera2/
      - recorder.status
    ...

episode_id_yyyy_mm_dd_hh_mm_ss_trimmed_timestamp_mcap_0.mcap

Topics and message types in the mcap:

Data source	Converted topic	Message type	Units / notes
Image	/sensor/<eternal_id>/image/compressed	sensor_msgs/msg/CompressedImage	Format: jpeg or h264
IMU	/sensor/<eternal_id>/imu	sensor_msgs/msg/Imu	Linear acceleration: m/s², angular velocity: rad/s
IMU	/sensor/<eternal_id>/mag	sensor_msgs/msg/MagneticField	Magnetic field: Tesla
Gripper	/sensor/<eternal_id>/imu	sensor_msgs/msg/Imu	Linear acceleration: m/s², angular velocity: rad/s
Gripper	/sensor/<eternal_id>/mag	sensor_msgs/msg/MagneticField	Magnetic field: Tesla
Gripper	/sensor/<eternal_id>/joint_states	sensor_msgs/msg/JointState	Position: 1. <eternal_id>_rad (radians) 2. <eternal_id>_dist (meters)
Mic	/sensor/<eternal_id>/audio	audio_common_msgs/msg/AudioDataStamped	Format: Raw PCM

metadata.yaml

metadata.yaml is written alongside mcap conversion and records:

1. Core metadata

   • version: rosbag2 descriptor version
   • storage_identifier: storage backend type (usually mcap here)
   • relative_file_paths: paths to associated raw MCAP files (supports split volumes)

2. Timing and statistics

   • starting_time: recording start time (usually Unix nanoseconds)
   • duration: total recording duration
   • message_count: total number of messages in the package

3. Per-topic definitions

   • name: topic name (e.g. /chatter)
   • type: message type (e.g. std_msgs/msg/String)
   • serialization_format: serialization format (for ROS 2, usually cdr)
   • offered_qos_profiles: QoS used when the topic was published—important for consistent playback, including reliability and history depth.

device_meta.json

Records the current sensor configuration (passed through from the frontend config).

status folder

Contains one subdirectory per sensor, named by the sensor eternal_id, each with a recorder.status file describing that sensor’s stream output and disk write status for this recording.

Platform

Post-processing topic list

Category	Topic	Message type	Notes
Raw: image	/sensor/<eternal_id>/image/compressed	sensor_msgs/msg/CompressedImage	<eternal_id> typical values: EgoCentric_Camera_0, EgoCentric_Camera_1 Left_Wrist_Camera_0, Right_Wrist_Camera_0 Left_Gripper_Camera_0, Right_Gripper_Camera_0
Raw: magnetometer	/sensor/Left_Gripper_IntegratedPose/mag /sensor/Right_Gripper_IntegratedPose/mag /sensor/Head_IMU/mag	sensor_msgs/msg/MagneticField
Raw: IMU	/sensor/Left_Gripper_IntegratedPose/imu /sensor/Right_Gripper_IntegratedPose/imu /sensor/Head_IMU/imu	sensor_msgs/msg/Imu	Linear acceleration: m/s², angular velocity: rad/s
Rectified image	/sensor/<eternal_id>/rect/compressed	sensor_msgs/msg/CompressedImage	<eternal_id> same typical values as raw image
Rectified image	/sensor/<eternal_id>/rect/camera_info	sensor_msgs/msg/CameraInfo	Intrinsics for the rectified virtual camera
Head pose	/io/pose/EgoCentric_Camera_0/traj	visualization_msgs/msg/Marker
Head pose	/io/pose/EgoCentric_Camera_0	geometry_msgs/msg/PoseStamped
Hand pose	/io/pose/Left_Hand /io/pose/Right_Hand	geometry_msgs/msg/PoseArray
Hand visualization	/io/pose/Hand/compressed	sensor_msgs/msg/CompressedImage	Optional debug visualization image