Cover the track, or push the timeline apart EN

How a video clip either covers your recording or pushes it later, and what the "too long" message means.

A video clip you add in the editor can cover the recording, or push the timeline apart so the recording waits while the clip plays. Covering is the default. Pushing is an option for video clips only.

The difference

Cover (default). The clip sits over the recording for its own length. The recording keeps its length, and the part under the clip is hidden. How the sounds mix depends on Merge audio. See Add a logo, image, clip or background audio.
Push timeline. The editor opens a gap in the recording at the clip's start. The clip plays alone in that gap, and the rest of the recording starts later. Nothing is hidden. The finished video is longer by the length of the clip.

Use cover for a logo, a short cutaway or a clip that should play over your talking. Use push when you want the clip to play on its own and don't want to lose any of the recording behind it.

Push the timeline apart

Add a video clip to the timeline and drag it to the point where you want it to play. See Add a logo, image, clip or background audio.
Right-click the clip's block on the asset track.
Choose Push timeline.

The recording is split at the clip's start, and a grey band appears on the main track to show the gap. The clip plays in that band. Any other assets that sit at or after that point move later too, so they stay over the same part of the recording.

While the gap plays, the recording contributes nothing. Its picture is black and it is silent, so you see and hear only the clip.

Your changes are saved as a draft. Viewers see the result only after you choose Apply & render. See Save a draft vs Apply & render.

Go back to covering

Either of these closes the gap and turns the clip back into a plain overlay. Anything after it moves earlier again.

Right-click the clip and choose Push timeline again. A tick next to it shows it's on.
Right-click the grey band on the main track and choose Remove gap.

Deleting the clip also closes its gap.

What a pushed clip can't do

A pushed clip is tied to its gap, so:

Duplicate segment, Move earlier and Move later aren't offered for it.
Dragging it along the track removes the gap and turns it back into a plain overlay.
Splitting, deleting, duplicating or reordering segments of the recording also removes every gap and turns those clips back into overlays. Set Push timeline up again afterwards. Do your cutting first and pushing last. See Cut out a mistake, and reorder what is left.

Why a clip is reported as too long

Video clips and audio can't be shortened. When you choose one in the Import assets window, the editor checks that it fits before it adds it. You may see one of these messages:

"This clip (…) is longer than the free space left in the recording (…)." The total length of your assets can't be more than the length of the recording. Delete an asset, or choose a shorter clip.
"This clip (…) needs one free gap that long, but the largest gap is only …. Move or remove assets to make room." The clip needs one uninterrupted stretch of free space on the asset track. Move or remove assets to open a wider stretch.

The check happens when you add the clip, before you choose Push timeline. Pushing doesn't get around it, and it doesn't create extra room: the gap grows the recording by exactly the clip's length, so the free space stays the same. A clip that's too long can't be added in either mode.

For the size and length limits on the files themselves, see Asset file types, size and length limits.