Crop a video using 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