How to do a split edit, J cut or L cut

A split edit lets the sound and the picture change at different moments, so a cut feels smooth rather than abrupt. In a J cut you hear the next shot before you see it; in an L cut the sound of one shot carries on over the start of the next. In Video by Zaweba you make one by holding Alt and dragging the picture or sound side of an edit point on its own, or by Ctrl+clicking edit points on several tracks for an asymmetrical trim that stays in sync.

The names come from the shape the clips make on the timeline. In a J cut the sound of the second clip reaches back under the end of the first, and the outline looks like a J. In an L cut the first clip's sound runs on past the picture cut, forming an L.

Why split edits work

Real attention doesn't jump all at once. In a conversation you often hear someone start to speak before you turn to look at them. A J cut copies that, letting a voice or a sound lead you into the next shot. An L cut does the opposite: you stay with someone's words while watching the reaction of the person listening.

They are the quiet backbone of interviews, dialogue scenes and documentaries. Straight cuts where picture and sound change together on every edit can feel choppy; a few split edits make the same footage flow.

Splitting a cut with Alt-drag

Lay the two clips side by side on the timeline, each with its linked sound.

Hold Alt and drag the edge of the sound clip at the cut. For a J cut, drag the second clip's sound earlier so it starts under the end of the first shot; the first clip's sound needs trimming back to make room, so drag that edge too. For an L cut, drag the first clip's sound later, over the start of the second shot.

Play across the edit. The picture still cuts at the same frame, while the sound now changes before or after it.

Alt-drag works on the picture side as well, which is simply the same split approached from the other direction.

Asymmetrical trims in the trim monitor

For more control, open View > Trim monitor (Ctrl+Shift+T). Ctrl+click edges on several tracks to select more than one edit point at once, choosing the picture edge on one track and the sound edge on another. Trimming them together makes a split edit while keeping everything in sync.

The trim monitor shows both sides of the cut with source timecodes, so you can see exactly which frames are in play. Nudge by a frame with the plus and minus one frame buttons or Alt+arrow keys. For a feel of the timing, use dynamic trimming: J or L play the trim backwards or forwards, K commits it as one undo step, and Esc throws it away.

Making split edits invisible

Keep it short. A few frames to a second of overlap is usually enough. Long overlaps start to feel like a mistake.

Mind the room tone. When one shot's sound runs under another's picture, any change in background noise becomes obvious. A short crossfade between the two sound clips smooths that over; fades can be dragged from the small square at a sound clip's corner.

Use rolling edits to move the whole cut. If the picture cut itself is in the wrong place, the rolling edit tool (N) moves it without changing the total length, and you can make the split afterwards.

Watch sync. Linked sound trims with its picture by default, which is what keeps lips in sync; splitting a cut deliberately breaks that link at one edge only. If something drifts, Ctrl+Z undoes the whole trim in one step.

Where to use them

Interviews benefit most: lead into a new answer with the speaker's voice over the end of a cutaway. Scenes with two people talking read better with L cuts on reactions. Travel and holiday films use J cuts on sound, where the noise of a market or the sea arrives just before the picture does.

Video by Zaweba is free software that works offline on Windows with no account, and split edits are part of its ordinary trim tools.