To blur faces in a video on iPhone, open the clip in HiddenFace, let it find the faces, tap the people you want hidden and share the result: it follows each person through the whole clip, so you never blur frame by frame.
The Photos app can't do this. Apple's own guide to editing video covers trimming, filters, rotation, speed, slow-motion and Audio Mix, and nothing that hides part of the picture.
We make HiddenFace. Every limit and number below was checked against the app's code for version 2.3.5 on 7 October 2026, not copied from the App Store page.
Blur faces in a video with HiddenFace, step by step
- Open the video. Tap the Video card on the home screen. Pick a clip from Photos, record one with the camera, or open one from Files. The limit is 10 minutes.
- Let it scan. The app shows Scanning video for faces while an on-device face model goes through the frames and groups what it finds by person.
- Choose who to hide. Tap a face to switch its cover on or off. A person you leave uncovered stays visible for the whole clip; a person you cover stays covered. If the detector missed something, like a face turned away or a name badge, tap Add Custom Zone and draw over it.
- Pick the cover. Under Cover Type choose blur, pixelate, a solid colour, an emoji or a sticker. Blur and pixelate have an Intensity slider.
- Export. Tap Ready, then Share. Choose Save Video in the share sheet to put it back in Photos, or send it straight to a chat.
The timeline under the video also trims the clip and splits it with Split at Playhead, so you can cut the part you don’t need before exporting.
Which cover to use for which video
| Cover | Adjustable | Good for |
|---|---|---|
| Blur | Intensity | Family clips where the faces should fade into the scene |
| Pixelate | Intensity | The look people read as “deliberately hidden”, as on the news |
| Solid colour | 8 colours | Anything public, or anything where the face must not be recoverable |
| Emoji or sticker | Which emoji or image | Kids’ birthdays and holiday videos you post to friends |
| Custom zone | Shape you draw | Backs of heads, screens, number plates, name badges |
What the export keeps, and what it changes
| HiddenFace 2.3.5 | |
|---|---|
| Longest clip | 10 minutes |
| Resolution | Same as the original |
| Sound | Copied across unchanged |
| File | MP4, H.264, about 10 Mbps on average |
| Where it’s processed | On the iPhone; nothing is uploaded |
| Needs | iOS 26 or later, iPhone or iPad |
| Price | Video is a Pro feature; photos are free |
Why we add grain to the blur
Plain blur is weaker than it looks. In June 2025 a team of researchers published a method that restores Gaussian-blurred faces and re-identified them with 95.9% accuracy. Their conclusion was that Gaussian blur should not be used to anonymise faces.
So HiddenFace adds random grain on top of every blur, scaled to the size of the face, which means the cover is no longer the clean, known pattern that kind of attack expects. It is still a blur. If the video is going on a public account, our own pick is a solid colour: there is nothing under it to recover.
Why the cover is bigger than the face
A face detector draws a tight box, and a tight box is not a whole head. When we measured our rectangular cover on 9 faces in a test photo, the chin fell outside it in all 9, and hair ran past it by a median of a third of the box. That one is not solved: every cover grows by a small fixed margin beyond the detected box, and that margin still leaves some hair showing.
The oval cover is where we went further. An oval that merely fits the box hides 88.9% of the face box and gives up the forehead, chin and ears, so HiddenFace scales it up until it hides 99.1%.
We also tried head-shaped masks. They covered more and looked worse, so we dropped them. If someone’s hair or a distinctive haircut would give them away, draw a custom zone over it.
Questions people ask
Can the iPhone Photos app blur faces in a video?
No. Apple’s guide to editing video on iPhone lists trimming, filters, rotation, playback speed, slow-motion and Audio Mix. There is no blur or pixelate tool, so you need a separate app.
Is a blurred face safe to post?
Not always. A 2025 paper (Zhai et al., arXiv 2506.12344) re-identified Gaussian-blurred faces with 95.9% accuracy and concluded Gaussian blur should not be used for face anonymisation. HiddenFace adds random grain on top of its blur. For a video going somewhere public, a solid colour or an emoji leaves nothing to restore.
Does HiddenFace upload my video?
No. Detection, tracking and rendering run on the iPhone, using an on-device face model. The video never leaves the device unless you share it.
How long can the video be?
Up to 10 minutes. A longer clip is rejected with the message Video too long; trim it in Photos first or split it into parts.
Do I keep the sound and the quality?
Yes. The audio track is copied across unchanged, and the video keeps its original resolution. It is re-encoded as H.264 MP4 at an average of 10 Mbps.
Is video blurring free?
No. The Video card carries a Pro badge and opens the subscription screen for free users. Blurring faces in photos is the free part of the app.
Can I blur a video from the Share button in Photos?
Not yet. The HiddenFace share extension accepts photos only. For video there is a Shortcuts action, Censor Faces in Video, which opens the clip in the HiddenFace video editor.
Blur the faces in your next video
HiddenFace is on the App Store for iPhone and iPad.
