Introduction to Compositing and Layering

Compositing involves stacking two or more video or graphics clips in a sequence on multiple video tracks. You can also scale, rotate, and reposition each clip using the controls in the Motion tab in the Viewer. The order that clips are stacked in the Timeline determines which images appear in front of others in the Canvas. You can have up to 99 layers, or tracks, of clips in Final Cut Pro.

Figure. Timeline window showing two video clips and a graphic layered in a sequence.

Methods of Compositing

Once you’ve layered clips in the Timeline, you can adjust how each one blends with the layers below using the following methods:

  • Opacity levels: This adjusts the transparency of a clip. You can adjust the Opacity parameter to subtly blend two or more layers together, or you can animate this parameter over time to create fade-ins and fade-outs. For more information, see Adjusting Opacity Levels of Clips.
  • Composite modes: This determines how the brightness and color values of one clip visually interact with those of clips beneath it. Composite modes are sometimes called blending modes. For more information, see Working with Composite Modes.
  • Alpha channels: In some cases, a graphic or video file includes an additional channel of grayscale information that determines the transparency of the image. Unlike a simple opacity control, an alpha channel specifies a unique transparency value for each pixel in the image. Alpha channels can be used as masks to hide parts of an image (such as blue-screen footage) or to create transparency that varies throughout the image. For more information, see Using Video and Graphics Clips with Alpha Channels. For information about enabling or disabling alpha channels in sequence settings, see Confirming Alpha Channel Status.

As an editor, you’ll find compositing useful for creating montages, abstract images, and titles over video. You can also use Final Cut Pro to make a rough arrangement of layers and then export those layers to Motion or Shake for even more advanced motion graphics and compositing effects. The more layers you have, the more creative you can get. However, you should aim to keep your designs as simple as possible, using the minimum number of layers necessary to achieve your visual design or effect.

Different Ways to Layer Clips in the Timeline

There are several ways you can layer clips in the Timeline.

  • Create a new track in a sequence, then edit clips into the new track.

    You can add one or more tracks to a sequence, depending on the effect you are creating. For more information, see Working with Tracks in the Timeline.

  • Drag a clip into an empty area of the Timeline, so a track is created for the new clip.

    You can drag a source clip to the unused space above (or below) the current tracks to create a new track for that clip. If you drag a clip above the tracks already in the Timeline, you’ll create a new video track. If you drag a clip below the tracks in the Timeline, a new audio track is created. For more information, see Working with Tracks in the Timeline.

  • Perform a superimpose edit.

    You can use a superimpose edit to quickly stack a source clip on top of any clips already edited into your sequence in the Timeline in preparation for compositing. If there isn’t an available track in your sequence, Final Cut Pro creates a new one for the source clip. For more information, see Three-Point Editing.

When you layer clips, the clip in the topmost track in the Timeline is the one that appears during playback in the Canvas. However, this is true only if:

  • None of the clips is set to be transparent (by changing the Opacity parameter setting)

  • None of the clips has an alpha channel

If you change the opacity level of one or more layered clips so they have some transparency, the clips blend and you see both images combined.

Moving Clips Vertically to Another Track

When you’re compositing, you may need to move a clip vertically from one track to another but keep its location in time in a sequence from changing. You might do this to:

  • Move a video clip on top of another one so that it appears in front

  • Move a clip to another track to make room for another clip being edited in

To do this, hold down the Shift key while you drag a clip up or down. For more information about moving clips to another track without accidentally moving them forward or backward in time, see Arranging Clips in the Timeline.

Adjusting Opacity Levels of Clips

Every video clip has an Opacity parameter that allows you to change the clip’s level of transparency. When you adjust the opacity level of one or more clips, they blend to create a single image. You can then use the resulting image as the background for another layer, such as a text or graphics layer.

Figure. Canvas window showing two clips blending together.

There are two ways you can adjust a clip’s opacity:

  • Drag the opacity overlay of a clip in the Timeline.

  • Open the clip in the Viewer and specify the Opacity parameter’s value in the Motion tab.

The Opacity parameter in the Motion tab and the opacity overlay displayed in the Timeline have identical settings. A change made to one is mirrored in the other.

When you blend multiple clips together using the Opacity parameter, it’s important to be aware of the color range, the amount of movement, and the overall amount of contrast and texture in the images with which you’re working. Balancing all of these qualities is what separates a good-looking composite from a confused jumble of images and motion.

To adjust the opacity of a clip (with no keyframes) in the Timeline
  1. In the Timeline, click the Clip Overlays control.

    Figure. Timeline window showing the opacity overlay being dragged to adjust the opacity level, and the Clip Overlays control.
  2. Drag the opacity overlay up or down to adjust the setting.

    To adjust the opacity of a clip with greater accuracy, hold down the Command key while you drag the opacity overlay.

    Note: The overlay appears as a black line if the clip is not selected and as a white line if the clip is selected.

    Figure. Timeline window showing the pointer changing to the Adjust Line Segment pointer as it is positioned over the opacity overlay, and a box with the percentage of opacity.
To adjust the opacity of a clip (with no keyframes) in the Motion tab
  1. Double-click the sequence clip you want to adjust to open it in the Viewer, then click the Motion tab.

    Note: When compositing clips in a sequence, make sure that you are always working on sequence clips and not Browser clips. For example, if you do a match frame edit or inadvertently open a clip from the Browser, you won’t be modifying a clip in the sequence and so you won’t see changes in the Canvas.

  2. Click the disclosure triangle next to the Opacity parameter.

    Figure. Motion tab showing the Opacity parameter, Opacity slider, number field, and the opacity keyframe graph area.
  3. Adjust the opacity by doing one of the following:

    • Drag the Opacity slider to the right or left.

    • Click the arrows at the right and left of the Opacity slider.

    • Type a percentage in the number field.

    • Adjust the Opacity parameter’s keyframe graph line.

      The pointer changes to the Adjust Line Segment pointer; a box shows the percentage of opacity as you drag the keyframe graph line.

    The opacity overlay in the Timeline can also be keyframed, enabling you to dynamically change the opacity level over time. For information on keyframing, see Animating Motion Effects Using Keyframes.