FFmpeg Scroll Filter: How to Continuously Scroll Video

This article explains how to use the FFmpeg scroll filter to continuously scroll a video horizontally, vertically, or diagonally. You will learn the core syntax of the filter, how to control the direction and speed of the scroll, and see practical command-line examples to apply this effect to your video files.

Understanding the scroll Filter

The scroll filter in FFmpeg allows you to pan or scroll a video continuously. When the video scrolls past the edge of the frame, it wraps around to the opposite side, creating an infinite looping scroll effect.

The filter uses two main parameters to control the speed and direction: * horizontal (or h): Controls horizontal scrolling speed. The value ranges from -1.0 to 1.0. * vertical (or v): Controls vertical scrolling speed. The value ranges from -1.0 to 1.0.

A positive value scrolls the video to the left (or up), while a negative value scrolls it to the right (or down). A value of 0 disables scrolling in that direction. The closer the value is to 0 (e.g., 0.005), the slower and smoother the scroll will be.

Practical Examples

Here are the commands to achieve different scrolling effects.

1. Continuous Horizontal Scroll (Right to Left)

To scroll a video continuously from right to left, use a positive horizontal value.

ffmpeg -i input.mp4 -vf "scroll=h=0.005" -c:a copy output.mp4

2. Continuous Horizontal Scroll (Left to Right)

To reverse the direction and scroll from left to right, use a negative horizontal value.

ffmpeg -i input.mp4 -vf "scroll=h=-0.005" -c:a copy output.mp4

3. Continuous Vertical Scroll (Bottom to Top)

To scroll a video vertically from the bottom to the top, apply a positive value to the vertical parameter.

ffmpeg -i input.mp4 -vf "scroll=v=0.005" -c:a copy output.mp4

4. Continuous Diagonal Scroll

You can combine both horizontal and vertical values to make the video scroll diagonally.

ffmpeg -i input.mp4 -vf "scroll=h=0.003:v=0.003" -c:a copy output.mp4

Adjusting the Initial Position

If you want the scroll to start from a specific offset instead of the default top-left corner, you can use the position parameters:

• hpos: Horizontal start position (as a fraction of the frame width, from 0 to 1).
• vpos: Vertical start position (as a fraction of the frame height, from 0 to 1).

For example, to start the video scroll with a 50% horizontal offset:

ffmpeg -i input.mp4 -vf "scroll=h=0.005:hpos=0.5" -c:a copy output.mp4