Apr 07, 2009 Update: If you’re looking for a way to mass-convert multiple CAF files, try using Switch to perform the task.

The iMovie application that comes included with every Mac OS X has a couple of cool sounds, jingles and other audio and music clips that can be used when creating movies.

The file format for these files are .caf, which stands for Core Audio Format. Read all about this format here.

The iMovie sound files are located in the Library > Audio > Apple Loops > Apple > iLife Sound Effects folder.

If you need to convert these files, or your own CAF files, into another format, say MP3 or AAC, you’ll need to use the included Garageband application to perform the conversion.

Step 1 – Launch Garageband, and select Create New Music Project.

Step 2 – Select a location and file name to save the project. We’re not going to be saving any project files, but this step is mandatory so we’ll just play along with it. After the conversion has been completed, you’ll have to manually delete this file, so choose a convenient location such as the Desktop

Step 3 – The default screen appears. You’ll see a keyboard and a single Grand Piano track. Click the red X to close the keyboard.

Also, delete the Grand Piano track as we won’t be needing it.

Step 4 – Launch iMovie, and bring up the Music and Sound Effects browser by using the menu, or pressing the shortcut keys [command + 1].

Step 5 – Have a look at the files that come with iMovie in the browser.

Use the pick list to select the type of iLife Sound Effect you want. Double-clicking the title of the sound effect previews the clip.

If you prefer, you could also click once on the title, and then click on the Play button.

Step 6 – Once you have decided on the clip you want to convert (I chose Forest Evening from the Ambience set in this example), arrange the Garageband and iMovie windows so that they’re next to each other. Click and hold the iMovie clip, and drag it to the Garageband window. Don’t release your mouse button yet. You’ll see that Garageband will automatically create a new track for you. Try to drag the clip as far left as it will go, making sure that the starting point of the clip falls on Beat 1.

Now, release your mouse button, and the track is created. If you did it wrong and didn’t get it to start on Beat 1, you could always drag the blue bar that represents the track, and drag it to the left. Or you could always delete the track and start over. If you want to confirm that the track was successfully imported into Garageband, click the Play button. Click the Play button again to stop.

Step 7 – Now you begin the conversion process in Garageband. Select Export Song to Disk from the Share menu.

The default conversion options are shown.

I select MP3 Encoder from the “Compress Using:” list.

I then choose Custom from “Audio Settings”. I do this in order to select the level of MP3 quality I want to encode the clip with.

I opt for 192 kbps Bit Rate, Use VBR, Highest VBR quality and Use Joint Stereo. I also uncheck Filter Frequencies Below 10Hz. Click the Default Settings button anytime you want to revert to the default values. Click OK once you’re done.

Step 8 – Verify your conversion settings and then click the Export button.

Choose a location for the MP3 file and enter a name for it. In this case, I just followed the title of the original .caf clip.

Step 9 – After a few seconds, or longer, depending on the complexity and length of the original clip, you’ll see your brand new MP3 file.