concatenate ImageClip

[vparitskiy]

Create several ImageClips:

clip_1 = ImageClip(imread('path_to_img.png'), duration=10)
clip_2 = ImageClip(imread('path_to_img.png'), duration=10)
clip_3 = ImageClip(imread('path_to_img.png'), duration=10)

merged_clip = concatenate_videoclips([clip_1, clip_2, clip_3])

It will fail with error:

Traceback (most recent call last):
 File "XXXXXX/tasks.py", line 93, in merge_video
    clip = concatenate_videoclips(clips)
  File "XXXXXX/lib/moviepy/video/compositing/concatenate.py", line 95, in concatenate_videoclips
    result.mask = concatenate_videoclips(masks, method="chain", ismask=True)
  File "XXXXXX/lib/moviepy/video/compositing/concatenate.py", line 72, in concatenate_videoclips
    tt = np.cumsum([0] + [c.duration for c in clips])
  File "XXXXXX/lib/python2.7/site-packages/numpy/core/fromnumeric.py", line 2114, in cumsum
    return _wrapit(a, 'cumsum', axis, dtype, out)
  File "XXXXXX/lib/python2.7/site-packages/numpy/core/fromnumeric.py", line 48, in _wrapit
    result = getattr(asarray(obj), method)(*args, **kwds)
TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

I discovered that while creating ImageClip instance with transparent=True, it sets self.mask to another ImageClip, but without duration.

And in concatenate_videoclips function it checks if any clip has mask and calculate duration. But duration is None, that's why TypeError.

Maybe, it should set mask.duration to clip.duration?

[ghost]

pull request #435 addresses this issue. I do bring up a question if there is a better way of setting the duration for the mask when we use ImageClip. Hopefully one of the more experienced developers will take a look for me.

[ghost]

This has been fixed in the repo. @vparitskiy, let us know if you run into other issues.