Move across image using Moviepy

Question

Using moviepy, I'm trying to make a video where it moves across an image.

Why isn't this working?:

image = ImageClip('image.png', duration=5)
image.set_position(lambda t: ('center', 50+t) )
image.fps = 30
image.write_videofile('video.mp4')

The outputted video is just a 5s video of the image (no movement)

Answer 1

There are two issues here.

Issue #1: ImageClip is not part of a composition

The documentation for ImageClip.set_position() says this:

Set the clip’s position in compositions.

Sets the position that the clip will have when included in compositions.

By "composition," it means a CompositeVideoClip. When an ImageClip is not part of a composition, set_position does nothing.

Issue #2: Return value of set_position is not used

set_position() has a somewhat confusing name. It does not actually set the position. It returns a copy of the Clip with the position set.

So this doesn't do anything:

image.set_position(lambda t: ('center', 50+t) )

instead, you need to do this:

image = image.set_position(lambda t: ('center', 50+t) )

Full corrected code

from moviepy.editor import ImageClip, CompositeVideoClip
image = ImageClip('image.png', duration=5)
image = image.set_position(lambda t: ('center', t * 10 + 50))
image.fps = 30
composite = CompositeVideoClip([image], size=image.size)
composite.write_videofile('video.mp4')

(Note: I also made the image movement larger so it would be more noticeable.)

_{(Thanks to the author of this issue for providing example code so I could figure out the problem.)}