Cropping Videos Using Ubuntu's FFmpeg: A Step-by-Step Guide

FFmpeg is a powerful, open-source tool for manipulating video files, and one of its most useful features is the ability to crop videos to specific sizes and positions. In this article, we'll explore how to use the -vf option in FFmpeg to crop your videos and achieve the desired output.

The -vf Option: A Brief Introduction

The -vf option stands for 'video filter,' and it's used to specify a section of the source video to use in the output by specifying the size and position of a rectangle to crop to. For example, if you want to create a new video file cropped to 720px x 600px and aligned 240px from the top, you would use the following command:

avconv -i input.webm -vf crop=720:600:0:240 output.mpeg

Breaking down this command, we can see that the -vf option takes the argument `crop=out_w:out_h:x:y`, where `out_w` and `out_h` specify the width and height of the cropped region, and `x` and `y` specify the position of the top-left corner of the cropped region.

Historical

In the past, FFmpeg had separate options for cropping videos, such as -croptop, -cropleft, etc. However, these options have been replaced by the -vf or video filter option, which is a little more complex but provides much greater flexibility.

Ubuntu and Libav: A Fork of FFmpeg

For those who use Ubuntu (like myself), it's worth noting that the command-line tools FFmpeg and avconv are interchangeable. Additionally, Ubuntu is transitioning from FFmpeg to libav, which is a fork of FFmpeg and is also compatible with most tools. The method described in this post should work with recent versions of either FFmpeg or libav.

In this article, we've explored how to use the -vf option in FFmpeg to crop videos to specific sizes and positions. With this powerful tool at your disposal, you can easily create cropped video files for a variety of purposes. Whether you're creating thumbnails, trimming unwanted edges from your footage, or simply wanting more control over your video output, FFmpeg's cropping capabilities are an essential part of any video editor's toolkit.

Ubuntu ffmpeg crop video