How to Blur Part of a Screen Recording (Emails, Keys, Names)
You recorded the perfect demo take — and your customer list, email inbox, or an API key is sitting in the corner of the frame. Re-recording with faked data is the traditional fix and the traditional time sink. The better fix is a blur region: a rectangle over the sensitive area, applied for exactly the seconds it's visible, baked into the export so no player setting can remove it.
What a good blur tool must get right
- Real blur, not a black box. A gaussian blur keeps the video looking professional; a censor bar screams "we leaked something."
- Time-ranged. The email address is only on screen from 0:12 to 0:31 — the blur should be too, not smeared across the whole video.
- Content-locked. If your edit zooms in, the blur must track the zoomed content, staying glued to the thing it hides. A blur pinned to screen coordinates slides off its target the moment the camera moves — and leaks a frame.
- Burned in. Blur applied at export, in the pixels. Overlay-based blurs in some players can be toggled off.
Blurring a region in DemoReel
- Open your recording in DemoReel and go to the Layers tab.
- Click Blur. A blur region appears on the preview; drag it over the sensitive area and resize it with the corner handle.
- On the timeline, drag the blur bar's edges so it covers exactly the span where the sensitive content is visible. Multiple blurs on separate tracks are fine — one per secret.
- Set the strength — enough that a paused 4K frame reveals nothing. Err strong; a heavy blur looks deliberate, a light one looks careless.
- Export. The blur is rendered into the MP4 itself, and it tracks correctly under any zooms you added.
Extra-sensitive workflows get a structural bonus here: DemoReel's whole pipeline is local, so the unblurred recording never touches a server either. With cloud editors, the original — secrets intact — is uploaded before you've drawn the first blur.
Blur checklist for product demos
- Browser profile chrome: your avatar, other tabs' titles, bookmark bar.
- Notification toasts — or better, enable Do Not Disturb before recording.
- Real customer names in tables — blur the column, not just one row; scrolling reveals the rest.
- URLs with tokens or internal hostnames in the address bar.
- The macOS/Windows menu bar clock and account name if the video should be timeless and anonymous.
When to pixelate, when to cut
A blur says "something is here that isn't yours to read" — fine for demos. If the sensitive content is the whole screen for a stretch (a wrong dashboard opened mid-take), don't blur it; cut the section out entirely — in DemoReel that's "Remove section" at the playhead, and the video simply skips it.