Rescreen / Free tools / Blur video
Blur video
Hide emails, keys and names in a video before you share it, free and with no watermark.
Blur part of a video
This browser cannot blur video. It needs WebCodecs to read and write frames, which is in current Chrome, Edge and Safari on a computer. Open this page in one of those and try again.
Drop a video here
or choose one from your device
MP4, MOV, WebM or MKV, up to 2.0 GB outside Chrome and Edge. Stays on your device.
- File
- Picture
- –
- Length
- –
Loading the first frame…
Blur and pixelation can sometimes be reversed. Use a solid cover for passwords, keys and other secrets.
This browser cannot play this file, so step through it on the timeline instead. The export still works.
Drag on the picture to draw a mask.
Drag a layer’s ends to set when its mask shows. To follow something that moves, add a keyframe, then move the mask at another frame. Keys: on the timeline, the arrow keys move one frame, with Shift one second. On a selected mask, the arrow keys move it and Shift with an arrow key resizes it. [ and ] set the selected mask’s start and end to the playhead, K adds or removes a keyframe, Delete removes the mask, Space plays, and Control or Command Z undoes.
Starting…
Check it before you share it
- Watch this copy at full size, and step through the frames where each mask starts and ends.
- Look for the same details elsewhere: tabs, address bars, notifications and pop-ups.
- Anything said aloud is still in the sound, unless you removed it.
- Captions, transcripts, thumbnails and titles are separate, and this tool does not change them.
- Keep the original private. If a password or key was ever shared, change it.
How to blur part of a video
Draw a mask over what you want to hide, check it, and export a new MP4.
Choose your video
Choose or drop an MP4, MOV, WebM or MKV file. The first frame opens in the editor. Nothing is uploaded.
Draw a mask
Drag a box over the part you want to hide, then pick a solid cover, blur or pixelate. A new mask lasts for the whole video. Drag the ends of its layer on the timeline to show it for less.
Follow anything that moves
If the page scrolls, press Add keyframe, move the playhead to a later frame and move the mask there. Step through the frames to check that it stays on target the whole way.
Export and review
Export the video, then watch the new file at full size before you share it. The masks are part of the picture, so nobody can turn them off.
Solid cover, blur or pixelate?
Use a solid cover for anything that must stay secret: passwords, API keys, card numbers and private messages. It replaces the pixels with black, so nothing of the original is left to work from.
Blur and pixelate look softer and suit things that only need to be out of the way, such as a face in the background or a customer’s name in a demo. Both keep an average of the pixels underneath, and that average can give text away. In 2022, security engineer Dan Petro published Unredacter, a tool that recovered pixelated text, and his advice was to use solid bars instead.
This tool makes each block about 1/36 of the shorter side of the picture, or 30 pixels in a 1080p video. That is strong, but no blur is proof against every attack, so the page does not call one secure. A video also gives an attacker many frames of the same text, each slightly different.
How the masks are applied
Each frame is drawn at full size, the masks are painted on it, and that picture is what gets encoded. The original pixels under a mask are not in the new file, and the original’s title, cover art and other metadata are left out too.
A leak in a redacted video is usually one frame: the mask comes on a moment late, or falls behind while the page scrolls. So a frame is masked if any part of the time it is on screen touches the mask’s time range, and a moving mask covers its whole path during that frame. When in doubt, the tool hides a little more.
The preview paints with the same code as the export. While paused, it decodes the exact frame the export will use, so the frame buttons show what the file will hold. During playback it follows the browser’s player, which can differ by a frame, so check the edges of a mask while paused.
Other ways to blur a video
- YouTube Studio. In the Editor, choose Blur, then Face blur or Custom blur. Custom blur can track an object or stay in one place. The video has to be on YouTube first, and YouTube’s help page says a saved edit can no longer be undone with Revert to original. Unedited videos with over 100,000 views may not be able to save changes unless the channel is in the YouTube Partner Program.
- FFmpeg. Its drawbox filter draws a filled rectangle from the command line. This suits a fixed area; a moving field takes more work.
- A desktop editor. Most video editors can place a shape over the picture and animate it. Add a filled shape with no fade, and export a new file.
- Record it again. With made-up data, nothing needs hiding. This is often the safest choice when private details show for much of the video. Our guide on redacting a screen recording covers how to choose.
Limitations
- This hides what is visible in the picture. It does not touch speech, or any subtitle or transcript files you keep alongside the video. You can remove all the sound, but not part of it; to cut a section out, use the video trimmer.
- Masks are rectangles, and they do not find or follow anything on their own. There is no face detection: you place every mask and keyframe yourself.
- The result is always a new H.264 and AAC MP4 at the same size and frame timing. Re-encoding can soften small text a little, so the export uses at least the original’s bitrate; the file can come out larger. To shrink it afterwards, use the video compressor.
- Only the first video and sound tracks are kept. Subtitles, chapters and metadata are left out. An HDR video comes out in standard colour.
- In Chrome and Edge on a computer, a big result is written straight to a file you choose. In other browsers files go up to 2.0 GB and the result has to fit in memory.
- Every frame is re-encoded, so a long video takes a while. Keep the tab open until it finishes.
- It needs WebCodecs, and the page says so before you start if your browser does not have it. We have tested it in Chrome and in Safari’s engine on a Mac, but not yet in Firefox. It is meant for a computer; on a phone, drawing small masks is harder and long videos may run out of memory.
Frequently asked questions
More for tidying a recording: the video trimmer, the silence remover, the crop video tool, and our guide to redacting a screen recording.
How do I blur part of a video?
Open the video here, drag a box over the part to hide and choose Blur. Drag the ends of its layer on the timeline if it should only show for part of the video, then export. You can add as many masks as you need.
Can blurred text be read?
Sometimes. Blur and pixelation keep an average of the pixels, and tools exist that have recovered text from pixelated images. Use a solid cover for anything that must stay secret.
Can I blur a moving object or a face?
Yes, by hand. Add keyframes and move the mask at each one, and it travels in a straight line between them. The more an object changes direction, the more keyframes it needs. The tool does not detect faces.
Can someone remove the blur from my exported video?
The mask cannot be switched off, because it is part of each frame and the original pixels are gone. A solid cover leaves nothing to recover. Blur and pixelate leave a rough average, which is why they are not for secrets.
Does this hide spoken passwords or captions?
No. It only changes the picture. Tick Remove the sound to leave all the sound out, and check any caption or transcript files yourself. Captions burned into the picture can be covered with a mask like anything else.
Is there a watermark or a time limit?
No watermark and no account. There is no set limit on length; the limits are the 2.0 GB file size outside Chrome and Edge, and how long you are willing to wait.
Is my video uploaded?
No. The file is read, masked and checked inside this page. We count anonymous page views, whether an export started, finished or failed, how many masks it used and technical facts such as the codec, never the file, its name, or where the masks were. If an export fails, the page can offer to send the file so we can fix the problem, and it is only sent if you choose to.
Spend less time editing
your next recording.
Create an account and record your first video in your browser.
No credit card required