iMovie '09 & iDVD: The Missing Manual

Extracting Audio from Video

iMovie is perfectly capable of stripping the audio portion of your footage apart from the video. The recorded audio suddenly shows up as an independent audio clip. Its pushpins indicate that it's locked to whatever spot on the video you've selected. Figure 9-13 shows the process.

Figure 9-13. Top: Highlight part of a filmstrip in your Event Browser, and then drag the selection into your storyboard. When you let go, the Drag and Drop menu appears. Click Audio Only. Bottom: The camcorder audio appears as an independent clip, which you can manipulate exactly as though it's any ordinary audio clip: delete it, shorten it, trim it, move it, and so on. You can create a reverb or echo effect by overlaying the same extracted audio several times.

The Audio Only command unleashes all kinds of useful new tricks that are impossible to achieve any other way:

• Make an echo. This is a cool one. Park the extracted audio clip a few frames to the right of the original, as shown at bottom in Figure 9-13. Use the Audio Adjustments panel (Volume Adjustments) to make it slightly quieter than the original. Repeat a few more times, until you've got a realistic echo or reverb sound.

• Reuse the sound. You can put the extracted audio elsewhere in the movie. You've probably seen this technique used in dozens of Hollywood movies: About 15 minutes before the end of the movie, the main character, ...