{
  "dataset_name": "AI Skating Coach - Clean 64-Class",
  "version": "1.0",
  "description": "Figure skating element recognition with 64 classes including multi-jump combinations",
  "total_samples": 5168,
  "train_samples": 4161,
  "test_samples": 1007,
  "split_ratio": "80/20",
  "num_classes": 64,
  "sequence_length": 150,
  "num_keypoints": 17,
  "coordinates_per_keypoint": 3,
  "duration_seconds": 5.0,
  "fps": 30,
  "keypoint_format": "COCO 17-point",
  "data_characteristics": {
    "no_augmentation": true,
    "no_class_weights": true,
    "no_synthetic_samples": true,
    "combinations_preserved": true,
    "format": "Pickle (NumPy-compatible, list of arrays)"
  },
  "data_sources": [
    "MMFS Dataset: 2D pose from competition videos (4,915 sequences)",
    "JSON Motion Capture: Professional 3D mocap (253 sequences)"
  ],
  "preprocessing_steps": [
    "Format unification (142-marker mocap \u2192 17-keypoint COCO)",
    "Temporal uniform sampling to 150 frames",
    "Coordinate normalization to [-1, 1]",
    "Velocity feature computation",
    "80/20 stratified train/test split"
  ],
  "keypoint_definitions": {
    "0-4": "Head (nose, left_eye, right_eye, left_ear, right_ear)",
    "5-10": "Upper body (left_shoulder, right_shoulder, left_elbow, right_elbow, left_wrist, right_wrist)",
    "11-16": "Lower body (left_hip, right_hip, left_knee, right_knee, left_ankle, right_ankle)"
  }
}