In today’s world of whiz bang, high-tech, digital editing, the power of the lowly overlap cut has been all but lost in the tumult. I’m sure many of you have heard the term overlap, pre-lap or post-lap before, but you may not know exactly why one would use this technique when creating a sequence. Understanding this subtle, simple and effective tool, which editors pull from their bag of tricks every day, will make you a more seasoned and better editor.

Overlapping is used in editing most any kind of story. In it’s most basic definition it refers  to having non-aligned cut points for adjoining sound and picture tracks as highlighted in red above.  This would be distinguished from a “straight cut”, where all tracks have an aligned cut point, as demonstrated within in the yellow highlight.

The term originated in the days of editing celluloid film, when the editor would physically extend the sound or picture and have it “lap over” the incoming or outgoing corresponding frames. Now of course we do this virtually in our editing software’s timeline. Avid’s Media Composer is a bit more intuitive when it comes to allowing to do overlaps naturally, as the tracks are always treated as being “unlinked” (or double system for you old-timers). On the other hand when working in FCP, all picture and sound tracks are linked by default. However, linking and unlinking are easily invoked in Final Cut with the keyboard shortcut, Shift-L.

Sidenote: Avid-trained editors are bound to get tripped up at first by Linked Selection vs. Clip Linking. These are two different functions, which can and do work together, but if you’re ever at you’re wits end and just want to move a piece sound separately from a piece of picture invoke shift-L or Edit menu > check or uncheck the Linked Selection option (fig. 3).

The overlap cut has a variety of uses. I employ it often simply to smooth out the sound transition of a cut. For example, let’s say you have a dialog scene between two people. If the audio ambiances of the two camera angles are badly mismatched, straight cuts between the two can have a distracting effect, jarring you out of the scene. Overlapping, or in this case “pre-lapping” the dialog for each cut can help you hide the difference between the two ambiances. This is also known as “masking” the cut. Of course now, digitally, you can enhance this smoothing effect even more by adding small 2-6 frame audio dissolves (fig. 4) not to mention by adding additional ambiance (background) tracks. Filmmakers also use the overlap as a way to usher an audience more immediately into a new scene by placing some of its audio under the last few shots of the the scene that is ending or other non-sync shots from the next one.

Sound editors make wide use of overlapping when preparing dialog and sound effects tracks for a mix. Often the objective is to make the whole track seamless from beginning to end. Here sound designers and mixers work with pre and post-lapped tracks to make the audio environment they are creating a cohesive whole. Overlaps are used both as a means of smoothing dialog as mentioned above, and also as a way to change the nature or character of a transition. Crickets could inform your audience the story is transitioning to something quiet or calm. Thunder, laughter or crying would create other types of foreshadowing. Combine all of them, ad reverb and… well you get the idea.  Thoughtfully placing music so it leads us into a new scene, or has the scene remain with the audience after it has finished takes advantage of the cinematic effect of overlapping in much the same way.

In the broadest sense, creating picture and sound collages or montages is what editors do. Overlapping is an extension of the concept of montage. The overlap and other editorial techniques are designed to keep your audience immersed in the film experience and fully invested in your story.