Create a Fit-to-Fill Edit in Apple Final Cut Pro

Posted on by Larry

[I re-discovered this effect while researching my webinar “Clip Speed Changes in Apple Final Cut Pro.”]

A fit-to-fill edit combines a replace edit with a playback speed change. It takes a marked clip in the Browser, then changes its speed to match the duration of a clip in the timeline.

The most common use for this is when editing clips to music. The musical beat often determines when edits need to occur, while the shot going into that spot may take a different amount of time to complete. A fit-to-fill edit solves that problem.

NOTE: Because a fit-to-fill edit changes the speed of a clip, it is not appropriate for any clip that has synced audio.

The process is simple: mark a clip in the Browser, then use it to replace a clip in the timeline. Here are the details:

Let’s pretend that I need to edit a music video. The music track is complete, I just need to add visuals.

I started by adding the music track into the Primary Storyline. I manually added markers to indicate the beat where I want to make an edit. For music-centered videos, adding the audio track into the Primary Storyline is a good way to keep everything in sync.

NOTE: The music track is colored gold because it is assigned a custom Role.

Then above the music I added Placeholders (Edit > Insert Generator > Placeholder) and trimmed them to match the markers as connected clips – or, more accurately, I trimmed them to match where the actual edits would take place.

NOTE: Neither of these steps is necessary to create a fit-to-fill edit, but, as long as I was thinking about music videos, I decided to add these steps. This is also a good application for using Placeholders. (Gaps won’t work, as gaps can only be added to the Primary Storyline.)

Each of these placeholder shots is two seconds long. (They can, of course, be any length, I’m just letting you know what these are in this example.)

Drone images courtesy of Terry Holland, Northeast Drone Video (

In the Browser, I selected my first shot and set an In and Out to mark the duration of the shot I want to add into my edit. The problem is that this Browser shot runs about six seconds, but the timeline only has room for a two second shot.

THIS is why the Fit-to-Fill edit exists. It will change the speed of the Browser clip to fit within the timing of the placeholder clip in the timeline.

Drag the clip from the Browser on top of a placeholder. (Any clip can be used as the target in the timeline, placeholders are convenient, but not required.) A dialog appears. Select Replace with Retime to Fit.

The playback speed of the Browser clip is changed so that the Browser clip marked by the In and Out now plays in the timeline. In this example, the clip speed was increased by 273%. In other cases, it might be slowed down. It all depends on the relationship between the marked duration (the duration between the In and Out) of the Browser clip and the clip in the Timeline.

NOTE: Final Cut requires that Fit-to-Fill edits use entire clips in the timeline as targets. FCP does not recognize using the In or Out in the Timeline for a replace edit.

Here’s another example. The first and third shots have been added, now I’m adding a shot between them. I don’t want the position of any clips to change, that would alter their position relative to the music, so I need to be sure the duration of the inserted shot doesn’t change. Fit-to-fill solves that.

NOTE: In this screen shot, I changed roles to reflect dialog and music (blue and green), and enabled thumbnails for the video clips. I also changed the timing of the video placeholders and clips. You can change timing at any time prior to replacing a clip using a fit-to-fill edit.


If you trim a clip after its speed was changed, the duration of the clip changes, but not the speed. Clip speed does not adjust dynamically. However, you can change the speed of any clip using the Retiming bar (Shortcut: Cmd + R), but that’s a technique for another tutorial.

Fit-to-Fill edits can be used with placeholders, gaps, even “normal” clips. They can be added to clips in the Primary storyline, or those that are connected clips. A fit-to-fill edit is simply a special form of a replace edit, where the speed of the new clip changes to match the duration of the clip in the timeline.

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