schema/object_boxes_schema.md

Object boxes JSONL

One JSON object per detection per frame (multiple lines per frame allowed).

Record format

{
  "video": "sample_01_shuttle_tube_packaging.mp4",
  "frame_idx": 100,
  "timestamp_sec": 3.333,
  "track_id": "tube_3",
  "class": "shuttle_tube",
  "bbox_type": "axis_aligned",
  "bbox": {
    "x_min": 0.42,
    "y_min": 0.18,
    "x_max": 0.71,
    "y_max": 0.65
  },
  "confidence": 0.87,
  "source": "auto_v1"
}

Fields

Field	Required	Description
video	yes	Matches MP4 filename in videos/
frame_idx	yes	Zero-based frame index
timestamp_sec	yes	frame_idx / fps
class	yes	Manipulation object from segments / object_taxonomy.md (objects only; hands live in *_hand_boxes.jsonl)
bbox	yes	Normalized 0–1 coords (origin top-left)
bbox_type	yes	axis_aligned or oriented
track_id	recommended	Stable ID across frames
confidence	yes	Detection score 0–1
source	yes	auto_v1, auto_guided_v1, or human_reviewed
rotation_deg	if oriented	Clockwise rotation of box

Oriented box (optional)

When bbox_type is oriented, bbox is still axis-aligned enclosing rect; add rotation_deg for the object major axis.

Sampling cadence

Object detections are exported on sampled frames (roughly one frame per 1–1.5 seconds; see sample_every in object_boxes_summary.json), not on every frame. frame_idx is the exact source-video frame, so timestamps remain precise.

This file contains objects only. Hand bounding boxes are a separate, denser stream — see hand_boxes_schema.md / *_hand_boxes.jsonl. Keeping them separate avoids mixing the sparse object cadence with the per-frame hand cadence.

For sparse object rows, interpolate or hold the last box across the gap between consecutive frame_idx values. The full-length overlay videos in previews/ hold by class (not track_id) to avoid ghost accumulation when the detector assigns new track IDs every sample.

Files

• sample_XX_*_object_boxes.jsonl — per-video object detections + tracks
• sample_XX_*_hand_boxes.jsonl — per-frame left_hand / right_hand boxes (see hand_boxes_schema.md)
• object_boxes_summary.json — aggregate object counts, classes, frames covered (frames_with_boxes, sample_every)
• hand_boxes_summary.json — aggregate hand-box counts, classes, frames covered
• previews/sample_XX_*_boxes_preview.mp4 — full-length overlay video showing both object and hand boxes