Why stabilizing puts black bars on your video
You stabilized a clip and now there are black edges flickering along the sides. Nothing is broken. This is how every stabilizer works — but you don't have to accept the bars.
Where the gaps come from
Stabilizing doesn't remove shake from the picture. It moves the picture to cancel the shake out.
If the camera jerked left on one frame, the app slides that frame right by the same amount to put it back where it should be. Do that on every frame and the result looks steady.
But sliding a picture sideways leaves nothing behind it. That empty strip is your black bar. The more the camera moved, the further the app has to slide each frame, and the bigger the gaps.
That's also why the bars flicker — they change size every frame, because the correction changes every frame.
The three ways out
1. Crop in (what most apps do automatically)
Zoom in a bit before stabilizing, so there's spare picture around the edges to slide into view. The gaps end up outside the frame and you never see them.
Cost: you lose the outside of your shot, and everything gets slightly softer because a smaller part of the picture is being stretched to fill the screen. Shakier footage needs a bigger crop. Really rough footage can lose a third of the frame.
2. Smooth less
Turn the strength down. Less correction means less sliding, which means smaller gaps and a smaller crop. You keep more of your shot, but you also keep more of the shake.
This is the real trade in every stabilizer, and it's worth understanding: smoothness and frame size are the same dial. Anyone offering you both is quietly doing one of these things without saying so.
3. Fill the gaps instead of cutting them off
Rather than throwing away the edges, fill the empty strips with something. A blurred, stretched copy of your own video works well — it's the right colours, it moves with the shot, and at the very edge of the screen nobody looks closely enough to notice.
This is usually the best answer for phone video, because you keep the whole frame at full sharpness. In Motion Track this is called Fill Edges. It's the same idea as the blurred bars you see on a landscape video posted to a vertical feed.
Stabilize without losing your frame
Fill Edges keeps the full screen. Free on iPhone.
The same thing happens with tracking. Locking an object in place moves the picture much further than plain stabilizing does, so the gaps are bigger. Filling the edges matters more there, not less. See locking an object in place.
How to end up with smaller gaps in the first place
All of this gets easier if the footage moved less to begin with:
- Film wider than your final shot. Give the app room to crop into. Step back a little.
- Hold the phone properly. Both hands, elbows against your body, walk heel to toe. More in the stabilizing guide.
- Don't pinch-zoom while filming. Zoom multiplies every movement, so it multiplies the correction and the crop too.
- Cut the worst bit out. The crop is sized for the worst moment in the clip. One bad stumble at the start forces a big crop across the whole thing — trim it and everything improves.
That last one is the biggest and least obvious win. If a clip needs a huge crop, find the single worst second and remove it.