record_video.py

import argparse
import os

import gymnasium as gym
import imageio.v2 as imageio

from enjoy import load_agent_from_checkpoint


def record(weights_path, output_path, seed=42, max_steps=1000):
    agent = load_agent_from_checkpoint(weights_path, seed=seed)
    env = gym.make("Acrobot-v1", render_mode="rgb_array")
    frames = []
    obs, _ = env.reset(seed=seed)
    for _ in range(max_steps):
        Hr, Hi = agent.encoder.encode(obs)
        action = agent.actor.argmax(Hr, Hi)
        obs, reward, term, trunc, _ = env.step(action)
        frames.append(env.render())
        if term or trunc:
            break
    env.close()
    os.makedirs(os.path.dirname(output_path) or ".", exist_ok=True)
    imageio.mimsave(output_path, frames, fps=30)
    return len(frames)


def main():
    parser = argparse.ArgumentParser(description="Record Acrobot-v1 replay video")
    parser.add_argument("--weights", default="hdppo-Acrobot-v1/weights.npz")
    parser.add_argument("--output", default="replay.mp4")
    parser.add_argument("--seed", type=int, default=42)
    parser.add_argument("--max-steps", type=int, default=1000)
    args = parser.parse_args()
    n = record(args.weights, args.output, seed=args.seed, max_steps=args.max_steps)
    print(f"saved {n} frames to {args.output}")


if __name__ == "__main__":
    main()