How to Blur a Moving Object in a Video Automatically

To blur something that moves — a license plate, a logo, a person walking through your shot — you draw a box over it once and let motion tracking handle the rest. The AI follows the object through every frame and keeps the blur locked onto it. In TrackBlur this runs entirely on your phone, iPhone or Android, offline, and the export has no watermark.

If you've ever tried doing this with keyframes, you already know why that one sentence matters.

The keyframe problem

Traditional editors make you animate the blur by hand: place a keyframe, nudge the blur, step forward a few frames, nudge it again. A car driving past the camera can easily need dozens of adjustments just to keep its plate covered for three seconds. Add a shaky handheld camera and it turns into real misery.

Motion tracking replaces all of that:

1. You mark the object once.
2. The AI follows it across the frames.
3. The blur moves with it, automatically.

Quick demo

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How to do it in TrackBlur

1. Draw a box over the thing you want to hide

Import your video and pick the Manual Blur tool. Scrub to where the object first appears and draw a box over it — oval or rectangle, whichever fits better.

2. Pick a tracking speed

• Fast — quick edits and simple, steady movement.
• Balanced — the default, right for most everyday footage.
• Precise — fast objects, complicated paths, or low light.

3. Hit track

The AI scans forward through the video and keeps the blur centered on the object. You can preview the tracking path and nudge things afterwards if something's off.

That's it — no keyframes.

One tip: if the thing you're blurring is a face, you may not need manual tracking at all. Automatic face blur finds and follows every face on its own, and selective face blur lets you pick specific people.

Why do this offline?

Think about what people actually blur: dashcam clips, house numbers, strangers, kids. Exactly the footage you don't want sitting on some web tool's server. Online blur tools need the upload to work — TrackBlur doesn't. Everything is processed locally, so the raw video never leaves your phone. It's also a lot faster than pushing a 4K file through mobile data.

Go deeper

The Motion Tracking tutorial walks through every setting, shape option, and tracking mode in detail — or just download the app and try it on a clip.

More guides like this:

• How to blur all faces in a video automatically
• How to blur only certain faces in a video