How can I include a moving 'arrow' in a clip?

[Swiffers]

I'm need to create and include inside my videos an animation with a moving arrow, like this

1. ->
2. -->
3.  -->
4.   -->
5.    -->
6.   -->
7.  -->
8. -->
9. ->

1 to 9 represents frames/or time.

What are your recommendations on how to do it ? For the moment my only idea would be to create an arrow image and add it using ImageClip('arrow.png') display it 1 second, move it 1 pixel, hide it, display it, etc.

Your advices are welcome

[Swiffers]

Is it possible to add transparent gif inside a clip? it's possible with ImageClip but would it keep the gif background transparency?

[Zulko]

You could do it using a composite video clip with an arrow whose position depends on time. Something like this:

final_clip = CompositeVideoClip([
    background_clip,
    arrow_clip.set_pos(lambda t: (300 + 20 * np.sin(t), 400))
]).set_duration(background_clip.duration)

where arrow_clip was loaded using Imageclip("my_arrow.png", has_mask=True).
Apologies for any syntax mistake. written in a hurry.

[Swiffers]

@Zulko thanks. If I use a .gif with a transparent background and add it as an imageclip('') will it keep the transparency?

[Zulko]

cant remember exactly, certainly yes but you would need to say "with_alpha" or something when you load the GIF with VideoFileClip

[Swiffers]

@Zulko I see withmask

will save the clip’s mask (if any) as an alpha canal (PNGs only)

But where is the option to load the GIF using VideoFileClip() with a transparent background ?

class moviepy.video.io.VideoFileClip.VideoFileClip(filename, has_mask=False, audio=True, audio_buffersize=200000, target_resolution=None, resize_algorithm='bicubic', audio_fps=44100, audio_nbytes=2, verbose=False, fps_source='tbr')

[Zulko]

has_mask ?

[Swiffers]

Perfect.

Why is it called a mask? I'm new to video edition. I thought that a mask would be used to show a part of the video (i.e: the part under the mask).