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Visual cropper

Interactive visual tool for creating FFmpeg crop filter values

The cropper opens in a new tab and uses a full-screen interface optimized for desktop. It works best on larger screens.
[ launch cropper ↗ ]

What it does

Drag a frame from your video onto the canvas, position the crop region visually, and the tool emits the exact -vf crop=… value you can paste into any encoding command.

Features

  • Visual interface — see exactly what you're cropping
  • Drag to adjust — click and drag the crop region to reposition
  • Precise controls — pixel-level dimension and offset inputs
  • Step alignment — snap dimensions to 2/4/8/16/32/64 for codec compatibility
  • Customizable mask — adjust mask color and opacity
  • One-click copy — copy the generated filter to your clipboard

How to use it

  1. Launch the cropper using the button above
  2. Drag and drop a frame from your video (or any image) onto the canvas
  3. Adjust the crop region — width/height inputs, X/Y inputs, or drag directly
  4. Choose step alignment (useful for codec requirements)
  5. Click Copy to get the crop filter value

Crop filter syntax

The FFmpeg crop filter removes unwanted portions of video. Basic syntax:

crop=w=WIDTH:h=HEIGHT:x=X_OFFSET:y=Y_OFFSET

Example: ffmpeg -i input.mp4 -vf "crop=w=1920:h=800:x=0:y=140" output.mp4 — crops to 1920×800, removing 140 pixels from the top.

Why step alignment matters

Many video codecs work more efficiently when dimensions are divisible by 2, 8, or 16. Using step alignment can improve encoding efficiency, prevent compatibility issues, and avoid codec warnings.

Tips

  • Get a frame first — extract one with ffmpeg -i input.mp4 -ss 00:01:00 -frames:v 1 frame.png
  • Check aspect ratio — make sure your crop maintains the ratio you want
  • Test on a short clip before processing the full video
  • Watch the borders — ensure the crop doesn't include black bars or unwanted edges