Jason Whong: Renaissance Man-in-Training

(note: I’m sorry if you were looking for instructions for iMovie HD. I forgot to install my copy of iLife ‘05, and didn’t think about it until wgima was nice enough to remind me to mention the version number. As I designed this tutorial for Chris, I’ll install iLife and examine how to do it in iMovie HD)

I’ve decided to write a few technical articles about iMovie here, because I think they will be useful to somebody.

One of the nifty features of iMovie is that you can easily add music accompaniment to your video. You can use it to set the mood, or you can even edit the video in time with the music.

Unfortunately, this feature is butting heads with a trend in modern music mastering: Loudness. When recording engineers create audio files, they try to make sure the volume unit (VU) meter gets as close to zero (LOUDEST) without going into the red (DISTORTION).

Most ambient sound is way below zero when recorded on a camcorder. Without precise control, it’s hard to get even narration to zero on a camcorder.

The result for people wanting to let music accompany their videos: music that is simply dropped into the video becomes the primary audio, because it is so loud. It overpowers most speech that accompanies the video.

When the music is too loud, it ceases to be a “music bed.” It becomes the most important audio of the piece because it is the only intelligible audio.

There are two solutions. You can either reduce the volume of the music, or increase the volume of the narration.

Personally, I prefer to reduce the volume of the music, because there’s no interpolation involved. (When you boost a digital signal, your software is making things up algorithmically to keep the sound whole. Something like that. Reducing the volume just shrinks the signal a bit.)

Here’s how to reduce the volume of the music:

First, look at the iMovie window. I have added an mp3 track as background music. It’s represented by the purple bar.

Click on the bar that represents the audio you’ve added. Then click the “Edit Volume” checkbox.

You’ll notice that when you click the checkbox, a purple line appears across the audio track. This line represents the volume. It’s about 2/3 of the way to the top, because if you wanted to, you could boost the music even further. Clicking on the line at various places will let you adjust audio levels several times in the same track. But we’re not going to do that. Instead, we’ll save time since we’re making the edit to the entire track.

We’ve typed in 40% (and pressed return to watch the change in the purple line), because it seems about right. Now we’ll play it back and listen. If the narration is still too quiet, we can take it down even lower. Typing numbers here is easier than dragging the line up and down.

Note, however, that as long as the “Edit Volume” checkbox is checked, you can’t move the track around. And if you click in the track, it will think you’re trying to make precise volume edits. So when you’re satisfied with the volume, uncheck the box.

That’s it for this morning. Later tonight, I’ll post a guide to codec selection.