What is rolling shutter?
It’s the way most digital video sensors capture a frame: one row at a time, from top to bottom, instead of all at once. If the camera or the subject moves while the rows are being read, straight lines lean, bend or wobble.
Free · runs in your browser
Why upright lines lean in a fast pan and shake turns the picture to jelly, and how to straighten your own clip in the browser while you watch the before and after.
Rolling shutter is the way most phone, drone and action-camera sensors record a frame: row by row from top to bottom, rather than all at once. The bottom of the picture is captured a moment after the top, so if the camera moves during that moment, upright lines lean in a pan and a fast shake makes the whole picture wobble like jelly. That wobble is often called the jello effect.
Because the distortion follows the camera’s own movement, it can be undone once that movement is known. The tool above measures it, works out how fast your sensor reads out, and shifts each row of every frame back into line while it steadies the shot. This page opens with the Jelly fix preset and the Split view, so you can drag the divider across a lamp post or a doorway and watch it stand up straight. If the frame moves as a whole rather than bending, that’s ordinary shake: start with fixing a shaky video instead.
Drop it on the box marked Drop a wobbly, leaning clip, press Ctrl+O (⌘+O on a Mac), or on a phone tap Choose a wobbly clip. It opens with Jelly fix, which turns on the Warp correction, and with Rolling shutter set to Auto.
While it is Analysing motion…, the camera’s movement is measured from frame to frame. Auto then estimates how long your sensor takes to read a frame from that movement alone, with no camera data needed.
In Split view, drag the divider over something that should be upright: a building edge, a pole, a door. On the left it leans or ripples; on the right it should stand straight.
If lines still lean, open More options, set Rolling shutter to Manual and raise Strength until they stop; if they lean the other way, lower it. Set Rolling shutter to Off to see the difference it makes.
Press Export video (Ctrl+Enter or ⌘+Enter), check the settings and press Export video again, then Download or Share the corrected copy. The sound is kept.
Pan quickly past a building and its walls tilt, as if the whole street were leaning. Each row of the picture was taken slightly later than the one above, by which time the camera had turned a little further. The faster the pan, the bigger the lean.
When the camera shakes quickly, the direction of the movement changes within a single frame, so the picture bends one way at the top and the other at the bottom. Played back, it ripples like jelly. Car mounts, handlebars and drones with an unbalanced propeller are the usual culprits.
Tilting the camera up or down quickly stretches or squashes the picture vertically, because the rows are recorded while the view slides past them.
A global shutter exposes every pixel at the same instant, so moving scenes and a moving camera record without bending. A rolling shutter reads the rows one after another, which lets sensors be cheaper, more sensitive and better at high resolutions, and is why almost every phone uses one.
| Rolling shutter | Global shutter | |
|---|---|---|
| How the frame is recorded | Row by row, top to bottom | Every pixel at once |
| Found in | Phones, drones, action cameras and most stills and video cameras | Some cinema and sports cameras, and many industrial and scientific cameras |
| Fast pans | Upright lines lean | Upright lines stay upright |
| Fast shake or vibration | The picture wobbles like jelly | The picture shakes but keeps its shape |
| Flash or strobe | A band of light across part of the frame | The whole frame lights up evenly |
Readout speed varies from camera to camera and from mode to mode. Many cameras read faster at lower resolutions or with a cropped sensor area, so the same shake bends less in 1080p than in full-width 4K. A faster shutter speed reduces blur but not the lean, because the rows are still read out one after another.
The analysis measures how the camera moved between every pair of frames. From that, the speed of the camera during each frame is known, and with the readout time, so is the distortion: how far each row was displaced and rotated relative to the middle of the frame. The renderer moves every row back by exactly that amount on your graphics chip while it draws the steadied frame.
Every preset except Timelapse starts with Rolling shutter on Auto, so any clip you steady here gets the fix. Timelapses are the exception: their frames are taken seconds apart, so the movement between them says nothing about how the camera moved while each one was being read.
Most editing apps have a rolling-shutter setting, usually next to their stabiliser:
It’s the way most digital video sensors capture a frame: one row at a time, from top to bottom, instead of all at once. If the camera or the subject moves while the rows are being read, straight lines lean, bend or wobble.
A global shutter records every pixel at the same instant, so motion never bends the picture. A rolling shutter reads the rows in turn, which is cheaper and works well at high resolutions, but distorts fast movement. Nearly every phone, drone and action camera uses a rolling shutter.
Mostly, when it comes from the camera moving. Knowing how the camera moved and how fast the sensor reads out, the distortion can be calculated and reversed row by row, which is what Rolling shutter does here. Distortion of fast-moving objects, flash bands and vibration faster than a frame can’t be undone.
It’s an After Effects effect, also available in Premiere Pro, that straightens rolling-shutter distortion without stabilising the shot. You set a Rolling Shutter Rate and a Scan Direction; here, Auto estimates the equivalent for you and steadies the clip at the same time.
Vibration from the motors and propellers shakes the camera faster than the sensor can read a frame, so each frame is bent a different way. Balanced propellers and good dampers prevent most of it; Jelly fix removes much of what remains, although a very fine buzz can stay.
No. Shutter speed sets how long each row is exposed, not how long the sensor takes to read all of them, so the lean stays the same. A faster shutter does reduce motion blur, which makes the corrected footage look sharper.
The flash fired while the sensor was part-way through reading the frame, so only some rows caught it. It’s a rolling-shutter effect, but it isn’t movement, and no stabiliser can remove it.