[Bug Report] VideoRecorder breaks with older version of MoviePy

[chrisnota]

Describe the bug

I was hitting the following error with VideoRecorder:

Moviepy - Building video /path/to/video/best-episode-0.mp4.
Moviepy - Writing video /path/to/video/best-episode-0.mp4

Process Process-1:
Traceback (most recent call last):
  File "/path/to/python/multiprocessing/process.py", line 314, in _bootstrap
    self.run()
  File "/path/to/python/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "/path/to/project/scripts/common/recorder.py", line 76, in record_video_worker
    video_recorder.stop_recording()
  File "/path/to/python/site-packages/gymnasium/wrappers/rendering.py", line 407, in stop_recording
    clip.write_videofile(path, logger=moviepy_logger)
  File "/path/to/python/site-packages/decorator.py", line 235, in fun
    return caller(func, *(extras + args), **kw)
  File "/path/to/python/site-packages/moviepy/decorators.py", line 54, in requires_duration
    return f(clip, *a, **k)
  File "/path/to/python/site-packages/decorator.py", line 235, in fun
    return caller(func, *(extras + args), **kw)
  File "/path/to/python/site-packages/moviepy/decorators.py", line 135, in use_clip_fps_by_default
    return f(clip, *new_a, **new_kw)
  File "/path/to/python/site-packages/decorator.py", line 235, in fun
    return caller(func, *(extras + args), **kw)
  File "/path/to/python/site-packages/moviepy/decorators.py", line 22, in convert_masks_to_RGB
    return f(clip, *a, **k)
  File "/path/to/python/site-packages/moviepy/video/VideoClip.py", line 300, in write_videofile
    ffmpeg_write_video(self, filename, fps, codec,
  File "/path/to/python/site-packages/moviepy/video/io/ffmpeg_writer.py", line 213, in ffmpeg_write_video
    with FFMPEG_VideoWriter(filename, clip.size, fps, codec = codec,
  File "/path/to/python/site-packages/moviepy/video/io/ffmpeg_writer.py", line 88, in __init__
    '-r', '%.02f' % fps,
TypeError: must be real number, not NoneType

I noticed my moviepy was on an older 1.0 version. Upgrading to latest fixed the issue.

I think VideoRecorder may not be compatible with some or all moviepy 1.0 versions. We should bump the minimum version number in the pyproject.yaml.

Code example

video_recorder: RecordVideo = env.wrap(
            lambda env: RecordVideo(
                env,
                os.path.join(task.agent_path, "videos"),
                episode_trigger=lambda episode: True,
                disable_logger=True,
                fps=50,
                name_prefix=task.name,
            )
        )
        # run the environment until the episode finishes

System info

Name: gymnasium
Version: 1.0.0
Ubuntu 22.04

Additional context

This is probably what caused #882, which was closed because the user wasn't able to reproduce (possibly after inadvertently upgrading?)

Checklist

• I have checked that there is no similar issue in the repo

[pseudo-rnd-thoughts]

Very helpful @chrisnota
Do you know what the minimum version of moviepy will work?
Is there an easy gymnasium side fix for moviepy v1.0?

[chrisnota]

Probably, but I'm not sure. Very busy with some deadlines currently, but I could take a deeper look later next week? Just wanted to make sure this got logged.

[chrisnota]

This is really a separate issue, and is really a bug on moviepy, but it seems like there are some interesting memory leaks with moviepy. I ran this code, and got the following plot:

from moviepy.video.io.ImageSequenceClip import ImageSequenceClip
import time
import numpy as np
import psutil
import gc
import matplotlib.pyplot as plt


def get_memory_usage():
    """Return the memory usage in MB."""
    process = psutil.Process()
    mem_info = process.memory_info()
    return mem_info.rss / (1024 * 1024)  # Convert to MB

# Store memory measurements
memory_usage = []
start_memory = get_memory_usage()
print(f"Initial memory usage: {start_memory:.2f} MB")

n = 200
for i in range(n):
    print(f"Iteration {i+1}/{n}")
    
    # Measure memory before
    before_mem = get_memory_usage()
    
    # Create clip
    frames = [np.random.random((100, 100, 3))] * 255
    clip = ImageSequenceClip(frames, fps=50)
    
    # Explicitly close and delete the clip
    # clip.close()
    # del clip
    # del frames
    
    # Force garbage collection
    # gc.collect()
    
    # Measure memory after
    after_mem = get_memory_usage()
    memory_usage.append(after_mem)
    
    print(f"Memory usage: {after_mem:.2f} MB (Change: {after_mem - before_mem:.2f} MB)")
    
    time.sleep(0.1)

# Analyze for memory leaks
final_memory = memory_usage[-1]
print(f"\nMemory Analysis:")
print(f"Starting memory: {start_memory:.2f} MB")
print(f"Final memory: {final_memory:.2f} MB")
print(f"Difference: {final_memory - start_memory:.2f} MB")

# Calculate memory growth rate
if len(memory_usage) > 1:
    memory_growth = (memory_usage[-1] - memory_usage[0]) / len(memory_usage)
    print(f"Average memory growth per iteration: {memory_growth:.4f} MB")
    print(f"Memory leak detected: {'Yes' if memory_growth > 0.5 else 'No'}")

# Plot memory usage
plt.figure(figsize=(10, 6))
plt.plot(range(1, len(memory_usage) + 1), memory_usage)
plt.title('Memory Usage Over Time')
plt.xlabel('Iteration')
plt.ylabel('Memory Usage (MB)')
plt.grid(True)
plt.savefig('memory_usage.png')
plt.close()

print("Memory usage plot saved as 'memory_usage.png'")

Using clip.close() helps a little:

However, regardless of whether you have closed the clip, calling gc.collect() after each iteration totally solves this issue:

So I'm going to suggest calling gc.collect() on stop_recording(). Still hoping to put together a PR for this.

[pseudo-rnd-thoughts]

Thanks @chrisnota, that sounds like a good plan for now.
Have you reported this upstream to moviepy?

[pseudo-rnd-thoughts]

@chrisnota Running your script on my MacOS with pip install --upgrade moviepy on Python 3.10 I don't appear to get the same memory leak results.

Default without clip.close, del clip, del frames or gc.collect()

Memory Analysis:
Starting memory: 51.94 MB
Final memory: 70.50 MB
Difference: 18.56 MB
Average memory growth per iteration: 0.0926 MB
Memory leak detected: No

Could you clarify what OS and MoviePy version your using?

[chrisnota]

I'm on ubuntu 22.04, moviepy==2.1.2