Stabilize

Select a video clip and open the Inspector’s Video tab, Basic page. Tick Stabilize in its section header. On a phone, the clip’s Edit sheet has the same section.

What happens when you tick it

Concat measures the camera’s movement in the clip’s file once, in the background, and the section shows “Measuring the shake… N%”. Until the measurement lands the clip plays as shot; then the monitor shows it steadied. Only the part of the file the clip uses is measured, plus a little either side for the smoothing, and a measurement already made is reused by every clip of the same file. Nothing needs downloading and nothing leaves your machine.

The three controls

Control	What it does
Smoothness	How much of the camera’s movement is smoothed away. Low keeps a pan or a walk and takes out the jitter; high leaves only the slowest moves. Starts at 50%
Max zoom	How far the picture may be enlarged to hide the edges the correction pulls into view, up to 150%. Starts at 120%
Tripod	Holds the frame completely still, as if the camera had been on a tripod, instead of following the camera’s intended move

The sliders answer at once: the correction is worked out live from the measurement, so there is no second wait.

Once measured, the section says what zoom the clip is drawn at (“Zoomed to 112% to hide the edges”). When Max zoom holds the correction back, it says how much zoom steadying every frame would take; raise Max zoom to steady the shakiest moments fully, or accept a little movement there.

Export and the API

An export measures any stabilized clip that has not been measured yet before it renders, so a file always comes out steadied. The monitor and the export draw the clip through the same correction. Scripts set it with the setClipStabilize edit; see Edit commands.

If Concat closed while measuring

The project still opens: the measurement it died in is skipped and a notice says so once. Turn Stabilize off and on again to retry.

A background removal painted on a stabilized clip lands where you painted it.