Editing soundtracks in iMovie?

October 2, 2004 8:34 PM

iMovie question (more iNside)

So there are these sound glitches I'm trying to do away with in a movie. I'm told the way to do it is to Extract Audio from the clips that are showing up and causing glitch sounds as they begin to play, even though their volume is set to the bottom.

The problem is that these tracks are refusing to let me Extract their audio. I hit Extract Audio, the pinwheel spins, and then everything's the same as before. What's wrong? I wonder if I have used up so many audio tracks that none are available for Extract Audio? Gotta get rid of these glitches.

Any help much appreciated.

posted by inksyndicate to computers & internet (3 comments total)

I'll look into this and get back to you. Darn that iMovie, it discourages teh technical detail!
posted by mwhybark at 12:22 AM on October 3, 2004

Thanks. Help! It seems to be some sort of bug, I wonder if I screwed up my system somehow.
posted by inksyndicate at 9:36 AM on October 3, 2004

You may already have done some of this. It's pretty much a recounting of what I did to learn about your problem.

1. Go to Preferences, and set "Show Audio Track Waveforms" to on. This will display the audio from the tracks as seismograph looking things, which will make it easier to see your glitches.

2. Set the editing ribbon view to 'timeline' instead of 'clips viewer'. You'll see three 'tracks,' one video clips and transitions, and two audio.

Confusingly to me, the audio tracks don't represent left and right, and can actually accommodate overlapping audio within the tracks - the dual presentation appears to be strictly an interface convention. I do not know how many actual mono tracks the system can handle, but the implied max of six is probably at least eight and maybe more - two channels per apparent track with more possible from layering audio. Of course, that will drop to two on output, as the audio will be flattened into 2-track stereo.

3. To do the extraction, the instructions I have say "select the clip, and then select 'Extract Audio' from the Advanced menu."

I tried this on an extant project and got your results, which is to say, nothing happened. I already have audio in both audio tracks.

I created a new project, imported some video that had audio and and repeated the experiement with no audio in the tracks.

Instead of a beach ball, I saw a dialog, "extracting audio," with a progress bar. Upon completion, the audio was displayed in the audio tracks area.

Therefore I surmise that extraction only works on clean projects; there may be more to it than that but I think you can experiment to find the parameters.

I did not experiment further to see if the procedure duplicated the audio, which could be problematic. My assumption is that extraction makes the video itself silent and places all the audio directly into the track area for editing.

Good luck!
posted by mwhybark at 2:53 PM on October 3, 2004