[Bug]: VecVideoRecorder overwrites previous video at each save

[curtiscjohnson]

🐛 Bug

Due to changes that happened with commit #1837 in vec_video_recorder.py, the video_name is no longer updated at each recording, which leads to the previous video being overwritten as self.video_name every time.

To Reproduce

import gymnasium as gym
from stable_baselines3.common.vec_env import VecVideoRecorder, DummyVecEnv
from stable_baselines3 import PPO
import glob


def test_video_save():
    env_id = "CartPole-v1"
    video_folder = "videos"
    video_length = 100

    vec_env = DummyVecEnv([lambda: gym.make(env_id, render_mode="rgb_array")])

    # Record the video starting at the first step
    vec_env = VecVideoRecorder(vec_env,
                               video_folder,
                               record_video_trigger=lambda x: x % 1024 == 0,
                               video_length=video_length,
                               name_prefix=f"agent-{env_id}")

    vec_env.reset()

    model = PPO("MlpPolicy", vec_env, verbose=0, device="cpu")

    model.learn(total_timesteps=2048)

    #print all videos in video_folder, should be multiple step 0-100, step 1024-1124
    video_files = glob.glob(f"{video_folder}/*.mp4")

    # Clean up
    vec_env.close()

    print(f"All video files saved in {video_folder}: {video_files}")


if __name__ == '__main__':
    test_video_save()

Relevant log output / Error message

Moviepy - Building video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
Moviepy - Writing video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4

Moviepy - Done !                                                                                        
Moviepy - video ready /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Saving video to /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Moviepy - Building video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
Moviepy - Writing video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4

Moviepy - Done !                                                                                        
Moviepy - video ready /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Saving video to /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Moviepy - Building video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
Moviepy - Writing video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4

Moviepy - Done !                                                                                        
Moviepy - video ready /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Moviepy - Building video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
Moviepy - Writing video /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4

Moviepy - Done !                                                                                        
Moviepy - video ready /home/curtis/baloo/baloo-gym/videos/agent-CartPole-v1-step-0-to-step-100.mp4
All video files saved in videos: ['videos/agent-CartPole-v1-step-0-to-step-100.mp4']

System Info

• OS: Linux-5.15.0-124-generic-x86_64-with-glibc2.29 # 134~20.04.1-Ubuntu SMP Tue Oct 1 15:27:33 UTC 2024
• Python: 3.8.10
• Stable-Baselines3: 2.4.0
• PyTorch: 2.4.1+cu121
• GPU Enabled: True
• Numpy: 1.24.3
• Cloudpickle: 3.1.0
• Gymnasium: 1.0.0

Checklist

• My issue does not relate to a custom gym environment. (Use the custom gym env template instead)
• I have checked that there is no similar issue in the repo
• I have read the documentation
• I have provided a minimal and working example to reproduce the bug
• I've used the markdown code blocks for both code and stack traces.

[araffin]

Hello,
thanks for reporting the issue, could you do a PR to fix it?

Edit: defining video name as a property should be an easy fix

[curtiscjohnson]

Hello, thanks for reporting the issue, could you do a PR to fix it?

Sure thing. I'll get a PR submitted in the next few days.

I'll also investigate whether this is indeed related to #2055 and let you know what I find.

[araffin]

@curtiscjohnson I found some time today, could you give #2063 a try?
(and also check if it fixes the W&B issue)

[curtiscjohnson]

@curtiscjohnson I found some time today, could you give #2063 a try? (and also check if it fixes the W&B issue)

Sounds good!

#2063 does indeed fix the issue. Using the same MWE as above, the output now matches the expected behavior.

MoviePy - Building video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
MoviePy - Writing video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4

MoviePy - Done !                                                                                              
MoviePy - video ready /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Saving video to /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4
MoviePy - Building video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4.
MoviePy - Writing video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4

MoviePy - Done !                                                                                              
MoviePy - video ready /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-0-to-step-100.mp4
Saving video to /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-1024-to-step-1124.mp4
MoviePy - Building video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-1024-to-step-1124.mp4.
MoviePy - Writing video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-1024-to-step-1124.mp4

MoviePy - Done !                                                                                              
MoviePy - video ready /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-1024-to-step-1124.mp4
MoviePy - Building video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-2048-to-step-2148.mp4.
MoviePy - Writing video /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-2048-to-step-2148.mp4

MoviePy - Done !                                                                                              
MoviePy - video ready /home/curtis/testing-sb3-temp/stable-baselines3/videos/agent-CartPole-v1-step-2048-to-step-2148.mp4
All video files saved in videos: ['videos/agent-CartPole-v1-step-1024-to-step-1124.mp4', 'videos/agent-CartPole-v1-step-0-to-step-100.mp4']

Regarding the W&B issue in #2055, still the same issue as mentioned in here. So I agree with your comment.