Creating and Using a Soundtrack Pro Script
[ This article was first published in the April, 2006, issue of
Larry's Final Cut Pro Newsletter. Click here to subscribe. ]
This technique occurred to me while I was developing a training DVD for Lynda.com on Soundtrack Pro because scripts in Soundtrack Pro have a quirky behavior that surprised me until I did some research on them.
Here’s a scenario. I have a sequence containing several talking-head interviews. The audio is low on all of them. An excellent way to boost audio is to normalize it, which is a feature FCP doesn’t have, but Soundtrack Pro does.
(Normalization is an audio process that increases the audio gain, or volume, of a clip without running the risk of distorting the clip’s audio. Normalization is much better than grabbing a red rubber band in FCP and dragging it, because when you drag to increase the volume of a clip, there is always a risk that you have increased the volume too much and distorted your mix.)
What scripts can do is automate adjusting the volume, or other audio parameters, across multiple clips with a single mouse click.
Here’s a sequence containing three interviews. (Scripts can work with any number of clips, I just selected three to keep things simple.)
Control+click a clip, in this case the first one, and select Send to > Soundtrack Pro Audio File project.
Soundtrack asks you where you want to store the audio temporary file it creates as part of this process. I recommend storing these temp files in your FCP projects folder. (Click here to read an article on how to organize your FCP files.)
Soundtrack opens and displays your clip. Press Cmd+A to select the entire clip.
Then, go to Process > Normalize and normalize your audio. (Click here to read my article on how to normalize a clip.)
So far, this is is nothing unusual. But, before you save the file, go to File > Save As Applescript…
… and give your script a name. In this case, I called it Normalize clip. (Here’s an important tip — don’t change the default folder Soundtrack suggests to store this script in. FCP only looks in this folder to see what scripts are available.)
Save your audio file project and switch back to Final Cut.
Now, here’s where scripts earn their keep.
Select each individual clip (one clip at a time) and choose Send > Soundtrack Pro Script > Normalize clip (or whatever you named your script).
Final Cut sends the clip directly to Soundtrack, which normalizes the audio, and sends the clip back to Final Cut. All automatically and in just a few seconds. This is a very fast way to make rapid adjustments to a whole flock of clips.
However, there is one large gotcha’ to worry about. Scripts work great when you select the entire clip to process. Where things break down is when you do something, such as a fade-in, that only modifies part of a clip.
In this case, when you save the script creating a two-second fade-in for a ten-second clip, Soundtrack DOESN’T say, “Add fade-in for first two seconds.” Instead, Soundtrack records the script as “Add fade-in for first 20% of a clip.”
So, let’s say the next clip that you send to Soundtrack for a fade in is a 20 second clip. Instead of adding a 2 second fade in, which is what you created, Soundtrack adds a 4 second fade in, because that’s 20% of the length of the clip.
Boy, did THAT surprise me the first time I ran into it!
So, to prevent unexpected problems, be sure to select and process entire clips when you plan to save your results as a script.
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Update: Lisa Brenneis writes:
I did post-production audio for years, and I have a mild panic attack every time I think about FCP users out there blithely applying STP scripts to their audio tracks and discovering later that STP scripts modify the original audio media file and then save the changes.That’s usually such a bad idea, especially if you plan on handing your audio off to a sound specialist.
FCP was designed as a non-destructive editing application and this glaring exception to the “no-destruct” rule is one of those Apple mysteries… anyway, I wish you would warn Newsletter readers that the STP script option will overwrite their original audio files.
OK, deep breaths….
Larry replies: Lisa, you are absolutely correct and I forgot to mention this. Using a script permanently changes your master file on disk, unlike an audio file project which is, generally, non-destructive. You provide an excellent caution.
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Update: Before we change the subject, though, Anders Elverhøy, from Norway, hastened to chastize me for even mentioning normalization:
In the audiobiz the golden rule is “no normalization”. The reason is simple, it sounds bad and destroys your sound. Since people in video mostly work with 16-bit sound, you will instantly run into rounding errors, they sound bad. Normalization will give you hard, unpleasant audio. It’s much better to insert a gainer plug-in and grab those red rubberbands and work your compressor. I know this isn’t the video editor’s dream, but there is no way around…. sorry…
Larry replies: Anders, when working in music you are correct, normalization often makes music sound unnatural. However, when working with interviews where the audio wasn’t that great to begin with, normalization can bail you out of some difficult situations. If there’s time, next month I’ll show you a different way to control audio using a Limiter filter.