Deflicker

Remove the flicker from slow motion video on your iPhone

A night golf range under stadium lights, filmed on an iPhone. Left, as shot. Right, the same frames after Deflicker Fusion.

Film slow-mo under LED or fluorescent lights and the camera catches them pulsing, so the clip comes out flickering or striped with dark bands. Deflicker measures the light in every frame and evens it out.

Download on the App Store See prices

Free to download. The on-device fix is free; its exports carry a watermark until you go Pro.

What changed in that clip, frame by frame

We measured the lit turf in all 147 frames. In the original it flips between a brighter and a dimmer level on almost every frame. On the 0 to 255 brightness scale, the average jump from one frame to the next was 5.4 as shot and 0.4 after Fusion. The slow rise that remains is in the original too: the scene itself, not the lights.

Brightness of the turf in each frame, as shot and after Fusion Two lines across 147 frames. As shot, the turf brightness zigzags between two levels on almost every frame, an average jump of 5.4 per frame. After Fusion the line is smooth, an average jump of 0.4, and rises slowly with the scene. 60708090100 As shot After Fusion 0 s 4.9 s
Average brightness of the lit turf in each frame, on the 0 to 255 scale, measured from the clip above.
Frame from the golf range clip after Deflicker Fusion, at the same brightness as the frames around it The same frame as shot, with the turf lighter than in the frames around it
Drag across one frame of the clip. The original caught the lights on a bright pulse, so its turf is lighter than in the frames on either side.

Two ways to fix a clip

The app has two engines. Most clips only need the one on your phone. Fusion is for flicker that runs deep or hits parts of the frame at different times, like the LED panels in this indoor range.

On iPhoneFusion
Where it runsOn your phone. The video never leaves it.On our GPUs. The clip is uploaded and deleted from our servers after 24 hours.
What it doesMeasures brightness area by area and smooths out the pulsing.Tracks every pixel across frames and rebuilds the light.
Best forWhole-frame pulsing and rolling bands.Deep LED and fluorescent flicker, and patches that flicker out of step.
While it worksKeep the app open.Stay for the upload, then leave if you like. The app shows how long is left.
CostFree with a watermark. Pro removes it.Uses Fusion clips, which come with Pro.

Fusion runs our own method, FlickerScope and Flicker Fusion, and it is public: read the code on GitHub or compare results on Hugging Face.

An indoor shooting range lit by LED panels. In the original the back of the range keeps dipping into shadow. Right, after Fusion.

From Photos and back again

Deflicker opens clips straight from your library and saves the fixed one next to the original. There is no timeline to learn.

  1. Deflicker home screen with a before and after example and the Choose a video button

    Pick the clip

    Choose a video opens your Photos library. Slow motion at 120 or 240 fps works, and so does regular video shot under artificial light.

  2. Deflicker screen for a chosen clip, with the engine, strength and method settings and the Remove flicker button

    Pick the engine and strength

    On iPhone at Medium strength with the Smart method suits most clips. Keep the app open while it works.

  3. The same screen with Fusion chosen, describing Flicker Fusion and showing that the video uses 1 Fusion clip

    Or send it to Fusion

    For deep or patchy flicker. Before you start, the app shows how many Fusion clips the video uses. You only stay for the upload.

  4. Result screen titled Flicker removed, with a draggable line between before and after and a Save to Photos button

    Compare, then save

    Drag the line across the result or hold to see the original. Save to Photos adds the fixed clip next to the original.

Prices

  • Free download The on-device fix and the before and after compare. Exports carry a watermark. $0
  • Deflicker Pro, yearly No watermark, and 15 Fusion clips every month. $29.99a year, about $2.50 a month
  • Deflicker Pro, weekly No watermark, and 5 Fusion clips every week. $4.99a week
  • 10 Fusion clips A one-time purchase for when you need more Fusion. $4.99once

One Fusion clip covers up to 1,000 frames of 1080p video, which is about 4 seconds of 240 fps slow motion. Longer or sharper videos use more, and the app tells you how many before you start. Prices are in US dollars and the App Store shows yours in local currency. Subscriptions renew until you cancel them in Settings.

Download on the App Store

Questions

Why does my slow motion video flicker?

Most indoor lights don't shine steadily. They pulse at twice the mains frequency: 100 times a second on 50 Hz power and 120 times a second on 60 Hz power. At normal frame rates the camera exposes each frame long enough to average those pulses out. At 120 or 240 fps each exposure is shorter than a pulse, so consecutive frames catch the light at different points in its cycle, and slow playback stretches the difference into visible flicker. Read the full explanation.

Can I fix flicker after filming?

Yes, in most cases. Flicker is a change in brightness from frame to frame, so software can measure it and even it out without a reshoot. That is what Deflicker does. The limit is detail that was never recorded: areas blown out to white or crushed to black in some frames can't be restored, so very deep flicker may leave slight unevenness. Fusion handles deep flicker best.

Does it work on 240 fps slow motion?

Yes. Deflicker works with 240 fps and 120 fps slow-motion clips as well as regular videos. 240 fps footage usually flickers the most, because each frame is exposed for 1/240 of a second or less, shorter than a single pulse of the light.

Is my video uploaded anywhere?

Not with the on-device fix: it runs entirely on your iPhone and nothing leaves the phone. Fusion runs on our GPUs, so it uploads only the clip you choose to send to Fusion, and that clip is deleted from our servers after 24 hours. There is no account and no sign-in.

What is a Fusion clip?

Fusion is counted in clips. One Fusion clip covers up to 1,000 frames of 1080p video, about 4 seconds of 240 fps slow motion. Longer or higher-resolution videos use more than one, and the app shows how many before you start. Pro Yearly includes 15 Fusion clips a month, Pro Weekly includes 5 a week, and you can add 10 extra Fusion clips for $4.99.

What is the difference between the on-device fix and Fusion?

The on-device engine measures brightness across the frame, area by area, and smooths out the pulsing. It is quick, private and right for most clips. Fusion is heavier: it tracks every pixel across frames and rebuilds the light, which helps with deep LED and fluorescent flicker and with parts of the frame that flicker out of step. It runs in the cloud and takes longer.

How do I cancel Deflicker Pro?

Subscriptions are handled by Apple. On your iPhone, open Settings, tap your name, then Subscriptions, choose Deflicker Pro and tap Cancel Subscription. Cancel at least 24 hours before the renewal date to avoid the next charge. You keep Pro until the end of the period you have paid for.

Which devices does Deflicker run on?

Deflicker is an iPhone app and needs iOS 17 or later. It works on videos in your Photos library, whether you filmed them on that iPhone or saved them there from somewhere else.