Moviepy is a Python library that allows you to edit and manipulate video files. One of the interesting effects you can create with Moviepy is a scrolling effect, where the video appears to be scrolling vertically or horizontally. In this blog post, we will explore how to create a scrolling effect using Moviepy.

Installation

Before we start, let’s make sure you have Moviepy installed. You can install Moviepy by running the following command in your terminal:

pip install moviepy

Getting Started

To get started, we first need to import the necessary modules from Moviepy:

from moviepy.editor import VideoFileClip, concatenate_videoclips

Next, we need to load the video file that we want to apply the scrolling effect to:

clip = VideoFileClip("input_video.mp4")

Scrolling Effect

To create a scrolling effect, we can use the crop method in Moviepy to select a portion of the video and shift it along a specific axis (vertical or horizontal).

For example, to create a vertical scrolling effect, we can crop the video horizontally and shift it down:

h, w = clip.size
scroll_speed = 50  # Adjust this value to change scrolling speed

def scroll_frame(t):
    offsetY = int((w * t * scroll_speed) % h)
    return clip.resize((h,w)).crop(y1=offsetY, y2=offsetY+h).resize((h,w))

scroll_clip = clip.fl(scroll_frame)

In the code above, we define a scroll_frame function that takes the time parameter t and calculates the offset along the vertical axis. We resize the clip to match the video dimensions and then crop it vertically based on the calculated offset. Finally, we resize the clip back to its original size.

Once we have the scrolling effect applied to a clip, we can concatenate it with other clips if needed. For example, if we want to add a title at the beginning of the video, we can create a separate clip for the title and concatenate it with the scrolling clip:

title_clip = TextClip("My Scrolling Video", fontsize=50, color='white', size=(clip.w, clip.h), duration=5)
final_clip = concatenate_videoclips([title_clip, scroll_clip])

Saving the Output

Finally, we can save the resulting video to a file:

final_clip.write_videofile("output_video.mp4", codec="libx264")

Make sure to choose an appropriate codec for your output video file, depending on your requirements.

Conclusion

In this blog post, we have learned how to create a scrolling effect in a video using Moviepy. By applying the crop method and manipulating the video frames, we can achieve various scrolling directions and speeds. Moviepy provides a powerful and flexible platform for video editing and effects, and the scrolling effect is just one example of what you can do. Experiment with different parameters and create your own unique scrolling effects!