{
  "dataset": "pendulum_cjepa_clevrer_3k",
  "seed": 20261014,
  "generation_mode": "random within per-regime bounds",
  "num_videos": 3000,
  "train_videos": 2400,
  "val_videos": 600,
  "val_design": "out-of-distribution physics regimes (NOT just a held-out seed)",
  "val_regimes": {
    "train": "in-distribution: theta0=\u00b1(15\u201340)\u00b0, omega0=\u00b10.2 rad/s, gamma=U(0.15,0.50)/s, Earth gravity, linear damping, no forcing (matches jimchen2/pendulum-cjepa-160f)",
    "val_high_damp": "OOD physics: gamma=U(0.55,0.90)/s \u2014 much stronger air resistance than any training video (fast envelope decay, tau as low as 2.2 s)",
    "val_low_damp": "OOD physics: gamma=U(0.0,0.08)/s \u2014 almost un-damped; swings barely decay, energy nearly conserved",
    "val_large_angle": "OOD physics: theta0=\u00b1(45\u201380)\u00b0 \u2014 strongly nonlinear regime; period elongated up to ~30% above small-angle value",
    "val_gravity": "OOD physics: g in {1.62 (Moon), 3.71 (Mars), 24.79 (Jupiter)} m/s^2 \u2014 periods shift by up to 2.5x either way",
    "val_quad_damping": "OOD physics (new law): drag = -beta*w*|w|, beta=U(0.10,0.35); envelope decays ~linearly instead of exponentially",
    "val_driven": "OOD physics (new forcing): periodic torque A*cos(2*pi*f*t+phi), A=U(0.35,1.0) rad/s^2, f=U(0.35,0.65) Hz near the ~0.5 Hz natural frequency \u2014 beats and resonant growth"
  },
  "frames_per_video": 160,
  "duration_s": 13.333333333333334,
  "fps": 12,
  "image_size": [
    196,
    196
  ],
  "codec": "H.264",
  "pixel_format": "yuv420p",
  "audio": false,
  "ode": "theta_ddot = -(g/L) sin(theta) - gamma*theta_dot - beta*theta_dot*|theta_dot| + A*cos(2*pi*f_d*t+phi)",
  "integrator": "RK4",
  "substeps_per_frame": 8,
  "gravity_m_s2": "9.81 (train); {1.62, 3.71, 24.79} (val_gravity)",
  "length_m": 1.0,
  "split_unit": "whole video",
  "normalized_labels": false,
  "simulated_seconds_for_questions": 28.0,
  "questions_per_video_target": 8
}