Chapter 10. Editing Audio

Chapter 10. Editing Audio

How important is audio in a movie? If you ever get the chance to attend an advance test screening of a Hollywood movie, the answer may be painfully clear. I've been to screenings where the audio in some scenes consisted of just what was recorded on set—no background music, no sound mixing to balance actors' voices and dampen background noise, no re-recorded dialogue to enhance enunciation. Although quite a bit of work goes into editing audio, people tend not to notice it unless something is wrong.

I covered some methods for capturing quality audio in Chapter 5, which is the first step. But audio can be much more than just video's underappreciated sibling. In this chapter, you'll see how editing audio tracks can give depth to your movie by working independently of the video, and by adding music, narration, and sound effects.

Changing a Clip's Volume

When you import footage, the video and audio are combined in the Timeline Viewer's video track (Figure 10.1). So, as you're editing video clips, you're also editing the audio—splitting, trimming, and cropping it with the visuals. You can control how loud an individual clip plays, or change the volume level within the clip.

Figure 10.1. Although the top track is usually referred to as the video track, it also contains the clip's audio.


To set a clip's volume evenly:

  1. In the Timeline Viewer, select the clip you want to edit.

  2. Click the Edit Volume button, located below the video and audio tracks.

  3. Use the volume control slider, or enter a percent value in the field, to set the clip's volume (Figure 10.2).

    Figure 10.2. With a clip selected, click the Edit Volume button and drag the volume control slider to adjust the clip's volume uniformly.


To change volume within a clip:

  1. In the Timeline Viewer, select the clip you want to edit.

  2. Click the Edit Volume button; a purple volume level bar appears within the clip.

  3. In the Timeline Viewer, click on the volume level bar to set a marker where you want the volume change to occur (Figure 10.3). iMovie creates the marker (a yellow circle) and a beginning point for the marker (a small square).

    Figure 10.3. iMovie 3 introduced the capability to edit volume levels within a clip. The audio between the beginning point and the volume marker is automatically incremented smoothly to a louder or softer level.


  4. Drag the marker up or down to increase or decrease the volume. All audio following the marker in that clip is affected.

  5. Drag the marker's beginning point to the right or left to determine how quickly the volume change occurs.

To remove a volume marker:

  1. Click a marker to select it.

  2. Press the Delete key.

Fading Audio In or Out

iMovie 2 featured controls for creating audio fades—increasing the volume from silent to full strength (fade in) or dropping the volume from full to silent (fade out). With iMovie 3's improved volume controls, you don't need the old Fade In and Fade Out checkboxes, but sometimes you still want the effect. Here's how to do it.

To fade audio completely in or out:

  1. Select a clip in the Timeline Viewer.

  2. Click the volume level bar to create a new marker at the beginning or end of the clip, depending on which fade you want.

  3. If you want a fade in, drag the beginning point (the square box) to the bottom-left corner of the clip (Figure 10.4).

    Figure 10.4. To fade in, move the beginning point to the bottom-left corner of the clip.


    If you're looking to fade out, drag the volume marker to the lower-right corner of the clip (Figure 10.5).

    Figure 10.5. To fade out, move the volume marker to the bottom-right corner of the clip.


To change the fade duration:

  • Drag the the beginning point left or right to dictate the fade's length (Figure 10.6). You may have to first move the volume marker—which drags the beginning point behind it—then adjust the beginning point to extend the fade duration.

    Figure 10.6. Move the beginning point left or right to determine the duration of the fade.


graphics/tick.gif Tips

  • If you drag a marker so that it lines up with an existing volume level, a dotted line appears and the marker is automatically deleted.

  • When you apply a Fade In or Fade Out transition (see the next chapter), the audio automatically fades to accompany the visual effect. But you can edit the volume levels in the transition, too (if you want the video to fade to black, but bring the volume down only halfway, for example).