{
  "status": "User-confirmed source mappings with documented FTP-1 export conventions",
  "instruction_source": "/Volumes/KINGSTON/2026_Tactile_data/extracted_images_trajectory/Task_Instruction.rtf",
  "episodes": {
    "boundary": "One original trial, from its beginning to its end",
    "complete_trials": 110,
    "recovered_partial_trial": "Retained separately; not counted as a complete episode",
    "note": "Episode boundaries do not by themselves establish cross-topic synchronization"
  },
  "instructions": [
    {
      "directory": "task1",
      "trials": "all_complete",
      "text": "Pull the hard drive out of the server.",
      "source_directory": "Datacenter"
    },
    {
      "directory": "task2",
      "trial_numbers": [
        1,
        2,
        3,
        4
      ],
      "text": "Take the light bulb out of the tape roll and place it on the table.",
      "source_directory": "Task2"
    },
    {
      "directory": "task2",
      "trial_numbers": [
        5,
        6,
        7,
        8
      ],
      "text": "Take the light bulb out of the tape roll and place it into another tape roll.",
      "source_directory": "Task2"
    },
    {
      "directory": "task3",
      "trials": "all_complete",
      "text": "Pick up one marker pen and place it in the clear plastic box.",
      "source_directory": "Task3"
    },
    {
      "directory": "task4",
      "trials": "all_complete",
      "text": "Move the pipe clamp from the left table to the right table.",
      "source_directory": "Task4"
    }
  ],
  "robot_state": {
    "source": "arm4_current_arm_joint_pose",
    "unit": "rad",
    "confirmed_channels_one_based": {
      "data_1": "Arm base left/right rotation, rad; part of the seven arm joints",
      "data_2_to_data_7": "Six arm joints ordered from base to wrist",
      "data_8": "Gripper joint"
    },
    "proposed_export_side": "right",
    "proposed_mapping": {
      "right_arm_joints": {
        "source_channels_one_based": [
          1,
          2,
          3,
          4,
          5,
          6,
          7
        ],
        "shape": [
          "T",
          7
        ]
      },
      "right_hand_joints": {
        "source_channels_one_based": [
          8
        ],
        "shape": [
          "T",
          1
        ]
      },
      "right_hand_joints_idx": {
        "proposed_slot": 28,
        "shape": [
          "T",
          1
        ],
        "meaning": "Gripper"
      }
    },
    "representation": "joint state trajectories; no unverified Cartesian pose conversion",
    "needs_confirmation": [],
    "gripper_note": "Every trial starts with the gripper open. Keep original rad values; opening direction and zero reference are not export prerequisites."
  },
  "cameras": {
    "arm4_gripper_usb_camera_stream_compressed": {
      "confirmed_location": "top/head camera",
      "proposed_key": "camera_ego_rgb"
    },
    "arm4_top_usb_camera_stream_compressed": {
      "confirmed_location": "wrist camera",
      "proposed_key": "right_wrist_camera_rgb"
    }
  },
  "tactile": {
    "same_gripper": true,
    "proposed_export_side": "right",
    "proposed_channel_order": [
      {
        "channel_zero_based": 0,
        "serial": "OG000470",
        "confirmed_location": "left gripper finger"
      },
      {
        "channel_zero_based": 1,
        "serial": "OG000144",
        "confirmed_location": "right gripper finger"
      }
    ],
    "groups": [
      "rgb",
      "depth",
      "force_grid"
    ],
    "area_indices": [
      0,
      1
    ],
    "sensor_model": "Xense (sensor-name field; no exact product model asserted)",
    "depth_metres_per_count": 1e-05,
    "invalid_raw_value": -32768,
    "force_grid": {
      "channels": 3,
      "physical_units": "Pending",
      "component_order_and_frame": "Pending"
    },
    "sdk_reference": {
      "source_archive": "/Volumes/KINGSTON/2026_Tactile_data/xensesdk-main_code (2).zip",
      "rgb": "Sensor.OutputType.Rectify; SDK README documents BGR",
      "force_grid": "Sensor.OutputType.Force; three-dimensional force distribution, shape (35,20,3)",
      "depth": "SDK README documents original Depth output in mm, typically shape (700,400)",
      "resultant": "Example maps ForceResultant indices to force x,y,z and torque x,y,z; this does not itself establish grid component order or physical units",
      "ros_timestamp": "Example uses ROS node clock immediately after SDK retrieval; not Sensor.OutputType.TimeStamp",
      "version_difference": "Example publishes depth 32FC1, force grid 32FC3, WrenchStamped and force_grid_image topic. Actual MCAP has 16SC1/16SC3, numeric_metadata, and different topic names.",
      "conversion_rule": "Use the actual MCAP numeric_metadata for int16 dequantization; do not apply the example float32/mm storage convention to current recorded counts."
    },
    "area_reference": "FTP-1 parse_data_univtac.py: left pad/thumb=0, right pad/index=1"
  },
  "timing": {
    "log_time_ns": "Available for all streams",
    "sensor_header_timestamps": "Available for Xense streams; ordinary-camera headers are zero in inspected sample",
    "sample_observation": "Task2/trial_1: 658 depth records but 159 distinct OG000470 sensor timestamps",
    "needs_confirmation": "Polling/caching and timestamp generation; repeated samples must not be treated as independent acquisitions",
    "sdk_example_note": "The supplied example has a nominal 30 Hz ROS timer and reads two sensors sequentially. Its timestamp/version behavior must not be assumed identical to the recorder that produced this dataset.",
    "conversion_policy": "Nearest MCAP log_time to each joint log_time, within each trial; preserve all joint timestamps and save matched source timestamps/offsets. No hardware capture synchronization claim."
  },
  "export_options": {
    "image_size": [
      224,
      224
    ],
    "image_resize": "OpenCV INTER_AREA direct resize",
    "numeric_tactile": "int16 original counts, invalid pixels zero-filled with validity masks",
    "wrist_pose": "not inferred",
    "actions": "derived by loader from future state trajectories",
    "gripper_angles": "original rad, no normalization or sign reversal"
  },
  "task_name_aliases": {
    "task1": "Datacenter",
    "task2": "Task2",
    "task3": "Task3",
    "task4": "Task4"
  }
}