Have you ever wondered what those green bars running along the top of your audio clips indicate? In a nutshell, Final Cut Pro is telling you that the audio sample rate for the clip does not match the sequence audio sample rate. There could be any number of causes for this, but the most frequent cause is editing audio imported from a CD (at 44.1 kHz) into a timeline that is setup for DV editing (at 48 kHz).

You may be tempted to think, “well, my audio sounds fine, why should I care?” The answer to that question has to do with CPU overhead. Whenever Final Cut Pro encounters an audio clip that does not conform to the sequence standard, it must up-convert the audio on-the-fly while playing it back. If we were only talking about a few audio tracks, this might not seem like such a big deal. However, add a few more video tracks with some filters, a few audio fades, and a partridge in a pear tree, and now your Mac has to do some serious heavy lifting to play all that back in real time. The end result? – possible dropped frames or reduced real time performance on playback.

Whenever possible, it’s always a good idea to bring in your audio at the correct sample rates. In this QuickTip, we’ll look at how to quickly resample mismatched audio in Soundtrack Pro.

1. In the timeline, control or right-click on the audio clip that needs to be resampled. From the menu choose “Soundtrack Pro Audio File Project”.

2. A Save dialog will appear prompting you to name and save your audio file. At this stage, you are actually saving a “Sountrack Pro Audio Project (stap) that you can edit non-destructively in Soundtrack Pro. Final Cut Pro replaces the original audio clip in the timeline with this new file adding the word “sent” to the clip name.

The stap audio file automatically opens in Sountrack Pro’s waveform editor.

3. From the Process Menu, choose “Resample”.

4. A window will appear where you can choose the sample rate you want to convert to. In this example, I’m choosing 48kHz to match the sequence settings.

5. Another window will appear asking if you want to include (or embed) the original audio file (the one with the wrong sample rate) into the project file (stap). I would choose the first option, Include Source Audio because should you ever need to move the project file to another computer, the original source file will travel along with it.

6. Click ok, save your project in Soundtrack Pro, and then jump back over to Final Cut Pro. In the timeline you will notice the green bar is conspicuously absent. Your audio now has the correct sample rate.