Hey,

When using MoviePy to store frame sequences as GIFs, I noticed that setting the fps parameter seems to have no effect. After digging around in the code a little bit, I found the issue.

In moviepy/video/io/gif_writers.py, line 442:

writer = imageio.save(
    filename, duration=1.0 / fps, quantizer=quantizer, palettesize=colors, loop=loop
)

Here, the duration passed to imageio is in seconds, which is consistent with imageio's documentation. Unfortunately, though, the documentation is erroneous in this case, as the underlying Pillow expects milliseconds.

I believe the best course of action is to ignore the documentation of imageio and pass the value as milliseconds.

Currently, this issue affects PyTorch's SummaryWriter, which uses MoviePy to store videos as GIFs.

Best,
Tim