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# Blur video with boxblur
- URL: https://ffmpeguru.com/blur-video-with-boxblur/
- Published: 2026-08-14T09:00:00.000Z
- Updated: 2026-10-13T17:59:37.000Z
- Author: FFmpeguru
- Tags: ffmpeg

Boxblur is the fastest blur in libavfilter and is the right tool when you need to anonymize a face, hide a license plate, or soften a background. It is also the building block of many other effects — a soft vignette, a focus-pull, or a face-blur before a privacy review.

## The command

```
ffmpeg -i in.mp4 -vf "boxblur=10:1" -c:v libx264 -crf 20 out.mp4
```

## What it does

The two numbers are luma radius and luma power. A radius of 10 means each output pixel is the average of a 10-pixel neighborhood around it; the power of 1 means the average is taken once. Increase the radius for a stronger blur; increase the power (2 or 3) for a more uniform result that takes longer to compute. Add a second pair \`boxblur=luma\_r:luma\_p:chroma\_r:chroma\_p\` to also blur the color channels.

## Requirements

Any video input. The filter is in libavfilter core. CPU-only, no hardware acceleration. For privacy-grade face blurring, increase the radius to 20 or higher so the region is unrecognizable.

## Things to avoid

- Using a radius below 5 for privacy. Small blurs leave enough structure to recover the original image, especially on a high-resolution source.
- Blurring the entire frame. The \`boxblur\` filter has no region selector; if you need to blur only part of the frame, use the \`crop\` and \`overlay\` filters around it.
- Combining boxblur with stream copy. The blur is a video filter, so the encoder must run. Use \`-c:v libx264\` (or your chosen encoder) explicitly.
- Confusing boxblur with gblur. gblur is a Gaussian blur with a different falloff curve, which may be what you want for an organic look.