Title : Crop a video using ffmpeg
Date : 20 December 2019
Tags : ffmpeg
If you ever need to crop a video, which mean that you want to reduce the area
of the video to a square of it to trim areas you don't want.
This is possible with ffmpeg using the video filter **crop**.
To make the example more readable, I replaced values with variables names:
- WIDTH = width of output video
- HEIGHT = height of output video
- START_LEFT = relative position of the area compared to the left, left being 0
- START_TOP = relative position of the area compared to the top, top being 0
So the actual commands look like
ffmpeg -i input_video.mp4 -filter:v "crop=$WIDTH:$HEIGHT:$START_LEFT:$START_TOP" output_video.mp4
If you want to crop the video to get a 320x240 video from the top-left
position 500,100 the command would be
ffmpeg -i input_video.mp4 -filter:v "crop=320:240:500:100" output_video.mp4