Chapter 22
File Compression and Your Music
IN THIS CHAPTER
Learning about compression
Making AAC and MP3 files
Distributing your music
The first release of GarageBand exported exactly one file format — the Audio Interchange File Format (AIF or AIFF). Today, GarageBand on the Mac can export your song in pretty much all popular file formats — AAC, MP3, AIF, and even the Windows standard for audio, WAV (or WAVE).
You can’t export an MP3 from GarageBand on an iDevice, but you can export AAC, AIFF, and WAV files, as well as Apple Lossless files, which aren’t an option on the Mac. AIF and WAV files are, by definition, uncompressed. Files compressed with MP3 or AAC are much smaller — 50 percent to 95 percent — than an uncompressed AIF or WAV file of the same song.
Compression, by its nature, removes part of the sound in the file. In theory, it’s the part that people can’t hear, but some people notice a big difference between uncompressed audio and compressed audio, even on cheap stereo systems. Many others can’t tell the difference. It’s a matter of degrees. Some people notice the difference between compressed audio files encoded (ripped) at bit rates of 160 versus 192 Kbps. Others hear no difference.
The bottom line is that smaller, compressed audio files sound good enough to most people most of the time. And for what it's worth, almost all streamed music today is compressed, which is probably why compressed music has become a de facto standard.
iPhones (and most other personal music players) and the Music app (or iTunes), along with most other personal music-playing software on most devices, can play both uncompressed and compressed files. But most people store most of their music as compressed audio files, so they can have five to ten times as many songs in the same amount of storage space.
Compression is all about choices, so this chapter looks at those choices and describes how to compress an audio file to send via email or iMessage or listen to on your iDevice (or other digital audio device).
Let’s look at the big picture before I talk about which option to use and what to use it for.
Understanding Compression
The quality of an AIF or a WAV file is top of the heap because it, by definition, contains 100 percent uncompressed audio. Nothing has been added or removed; every note, breath, harmonic, overtone, string noise, buzz, hiss, and other sound in the master recording is in an AIF or WAV file.
About uncompressed audio files
AIF (and WAV) files are uncompressed audio — the real deal. AIFF (or AIF) is the Mac standard for uncompressed audio; WAVE (or WAV) is the Windows standard.
Songs on your store-bought audio CDs appear as AIF files in Finder, as you can see in Figure 22-1.
Technically, the files on an audio CD are Red Book Audio files, which are slightly different from AIF files. The technical aspects aren’t important; the important part is that when you shove an audio CD into your Mac, it sees Red Book Audio files and automatically thinks of them as AIF files, as shown in Figure 22-1. No conversion or translation is needed — to your Mac, Red Book Audio files are AIF files and vice versa, even if the rest of the world says that Red Book and AIF are different.
FIGURE 22-1: Insert an audio CD, and your Mac sees AIFF files.
Although uncompressed audio may be the right format for shiny silver discs, it's not the right format for email, streaming, texting, or the web because uncompressed audio files are gargantuan.
About compressed audio files
MP3 and AAC are the two most common compressed audio file formats on the Mac. MP3 came first and has essentially been the compressed audio standard for many years. Then, when Apple introduced the iTunes Music Store, it also introduced the AAC file format, which is used for music purchased from the iTunes Music Store as well as songs streamed through Apple Music.
Figure 22-2 is worth a couple of thousand words — I shared (saved) a one-minute song in each file format, at each available quality level. The exported files are sorted by size from biggest (top) to smallest. Note how one minute of uncompressed audio (16.9 megabytes) is an order of magnitude bigger than the same minute compressed at the lowest setting (under 600 kilobytes).
Table 22-1 is a handy reference to the file types and the common ways in which each type is used. You find out how to save your own songs in those formats in the next section.
FIGURE 22-2: Compare the file size of the same song saved in four different file formats.
TABLE 22-1 File Types Large and Small
|
File Type |
Compressed? |
What’s It Good For? |
|
AIF |
No |
Burning Audio CDs, listening, and archiving music in a file format that retains all available audio information. Can be used with iDevices, but files are 5–10 times the size of compressed formats. |
|
WAV |
No |
This Windows file format is the equivalent of an uncompressed AIF file on a Mac. Use it for sharing files with Windows users. File sizes are 5–10 times the size of MP3 files, which is the compressed file format of choice among Windows users. (AAC is the compressed format of choice on the Mac.) |
|
Apple lossless |
Compressed, but lossless |
Music app or iTunes, or for archiving music in a file format is smaller than an uncompressed file. In theory it sounds the same as AIF or WAV in a significantly smaller file. Can be used with iDevices but files are 3–7 times the size of compressed formats. |
|
MP3 |
Yes |
iTunes, email, the web, and sharing with Windows users. Files are much smaller than any uncompressed or lossless format, making MP3s ideal for almost all uses. |
|
AAC |
Yes |
Same as MP3 but is Mac-centric. Slightly smaller files than MP3 with slightly better sound quality. Alas, some Windows users can’t play AAC files. |
Sharing Your Masterpiece
As I mention in the preceding section, different file types work better for different purposes, whether that is playing a song on your iDevice, emailing a song to a friend, or making sure that as many people as possible can listen to your song however they want to.
Each compressed file format can encode your song at four different bit rates — the higher the bit rate, the higher the quality. Alas, the higher the bit rate, the bigger the file.
Because the procedure for exporting (sharing) finished songs differs on iDevices and Macs, you explore them one at a time.
Sharing your songs from a Mac
Now that your song is finished, you probably want to share it with others so they can listen to it on their favorite device. The solution is GarageBand’s Share menu.
Following is a brief description of the Share menu options:
-
Song to Music: Choose this option to share a song to the Music app (macOS Catalina or later) or iTunes. This option allows you to sync the song to mobile devices. Songs can be shared to Music in any compressed or uncompressed file format at any quality level.
When you choose this option, the Share to Music dialog appears, as shown in Figure 22-3.
The dialog is prepopulated with the information you provide in the My Info tab of GarageBand’s Preferences.
FIGURE 22-3: The Share to Music dialog lets you edit your song info before sharing.
Choose the quality level you prefer from the Quality pop-up menu and then click Share. The whole song is then shared, with any silence at its beginning or end automatically trimmed.
To export part of your song, enable the Export Cycle Area Only, or Length of Selected Regions check box and set the cycle area or select a region or regions.
When you click Share, the song appears in the Music app (or the iTunes library in macOS Mojave or earlier). Now you can add the song to a playlist, burn it to a CD (as described in Chapter 23), or sync it with your iDevices.
-
Song to Media Browser: Choose this option to share audio files to Media Browser, where you can view and open them from other Apple applications, including Mail, iMovie, Notes, and Final Cut Pro X.
The entire project is saved as an audio file with the same name as the project, with any silence at the beginning or end trimmed automatically before the file appears in Media Browser.
If cycle mode is enabled, only the part of the project between the start and end of the cycle area will be shared.
-
Song to SoundCloud: SoundCloud is a popular music website used by bands and other musical artists to share their music. You need a SoundCloud account to use this option. When the Share to SoundCloud dialog appears, tap Change and enter your login and password.
To share a file from your disk, select the File radio button; to share the current song, select the Bounce radio button. Now fill in the information for the song and choose a quality level and visibility and permission levels for SoundCloud. When everything is just as you want it, click Share. Within a few minutes your song will be available on SoundCloud.
-
AirDrop: Choose this option to use the macOS/iOS AirDrop feature to share your song or GarageBand project wirelessly with a nearby Mac or iDevice (within about 6 feet). Choose Project or Song; edit the title (if you care to), choose a file format and quality level from the drop-down menu, and then click Share.
Note that to use AirDrop, both devices must have AirDrop turned on and Bluetooth enabled, and must be connected to the same Wi-Fi network.
- Mail: Choose this option to share your song or GarageBand project via email. Choose Project or Song, edit the title (if you care to), choose a file format and quality level from the drop-down menu, and then click Share.
-
Burn Song to CD: This option is enabled only on Macs with a CD burner or other compatible optical drive (internal or external). If you have one, you can choose this option to burn the current song onto an audio CD that you can listen to in most CD audio players or computers with optical drives.
To burn a song on a CD, choose this option and then insert a blank CD disc in your drive. Soon thereafter you’ll have an audio CD with one song that can be played on most (but not all) home, portable, automobile, and computer CD audio players.
-
Export Song to Disk: Choose this option to create a compressed or uncompressed audio file on your local disk. When you do, you’ll see a standard Save file sheet like the one in Figure 22-4.
First choose a file format (AAC, MP3, AIFF, or WAVE), and then choose a quality level from the drop-down menu. Navigate to the folder you want to save the file into and then click Export.
- Project to GarageBand for iOS: Refer to Chapters 19 and 21 for information on sharing projects to and from iOS.
FIGURE 22-4: GarageBand’s Save sheet lets you choose a file format and quality level for your exported file.
And those are your options for exporting a song from GarageBand on your Mac for others to enjoy.
Sharing your songs from an iDevice
Exporting a project from an iDevice works pretty much the same as on a Mac. However, the steps are slightly different, so this section gives you the scoop on sharing songs and projects from iDevices:
- Tap the my songs icon in the control bar, tap the Select button, and then tap the project you want to export.
-
Tap Share at the bottom of the screen, and then tap Song on the Share Song sheet to export the file as a song.
The other sharing options — Ringtone and Project — are discussed in Chapter 19.
- Tap the file format you prefer — Low, Medium, High, or Highest AAC, Apple Lossless, or Uncompressed AIFF or WAV.
- (Optional) Edit the Artist, Composer, and Album fields if necessary.
-
(Optional) Choose a photo as the cover image for this song.
Note that this option is not available if you’re exporting an AIFF or a WAV file.
- Tap Share.
-
Tap the option you prefer on the Share Sheet to share the file.
I typically use AirDrop to send the song to my Mac or other iDevices wirelessly, but feel free to use Messages, Mail, Dropbox, Google Drive, or whatever floats your boat (as long as it gets the song from your iDevice to where you want it).
And that’s how you share a song from your iDevice.
If you’re wondering how much compression is the right amount for your ears, check out the next section.
How Much Compression Can You Stand?
Some ears are more sensitive or discerning than others. So how much different do songs ripped (compressed or encoded) at different bit rates sound to you? Here’s an easy way to find out:
The trick is to create a playlist in the Music app (or iTunes) with two or three songs in pristine, uncompressed AIF (or WAV) format, plus MP3 or AAC versions (or both) compressed at different bit rates.
With such a playlist on your Mac or iDevice, you can listen to the same passage with different amounts of compression applied and determine which one you prefer.
You’ll need AIF or WAV files for the songs you want to test. If you don’t happen to have them, you can copy them to your Mac from store-bought CDs. To get started, choose two or three songs you know well.
Choose songs with wide dynamic ranges — both loud and soft passages — which will help you evaluate the effects of compression.
When you have your songs selected, use the uncompressed AIF or WAV version as the master to export versions in the compressed formats you want to test, adding the file format and bit rate to the filename when you export, as shown in Figure 22-5.
FIGURE 22-5: My compression testing playlist with the file format and bit rate appended to each song.
You may want to make a playlist with more versions of each song. I like to try to hear the difference between three settings — Lowest (64), Highest (256), and Uncompressed, which are three of the most common bit rates.
I’ve performed this test many times and ultimately decided that AAC at 160 Kbps was good enough for me. I couldn’t hear much (or any) difference between 160 Kbps and 192 Kbps. Even if there was a difference, it wasn’t enough to justify the bigger (192 Kbps) files.
One last thing: Feel free to put additional songs or bit-rate variations on your playlist if you have enough space for them.
Distributing Your Music
You may want to send the song you made in GarageBand and compressed in iTunes to your friend via email, or you may want to post the compressed version on a web page. You know where that song is located in the Music app or iTunes library, right? But where is the actual file stored on your hard drive?
Finding the song file on your Mac
The easy way to find the file for any song in your Music or iTunes library is to select the song (click it) and then choose File ⇒ Show in Finder or press ⌘ +R. Thinking of this command as “Reveal in Finder” helped me memorize the shortcut quickly.
Finder becomes active, the appropriate window opens, and the song file is selected. That’s where it is on your hard drive.
Of course, you can also use Spotlight to find your song, but the Music app’s Show in Finder command is faster, especially if the Music app is already open. (If it’s not open, a Spotlight search may be faster.)
Sending AAC or MP3 files via Mail or Messages
There’s nothing special about compressed audio files (AAC or MP3). Well, there’s something special — they sound almost as good as files ten times their size — but there’s nothing special about enclosing an MP3 or AAC file in an email message.
If you’re sharing from your device, use the Share sheet to choose Mail or Messages (or AirDrop).
If you’ve exported the file previously, you can attach it to an email or iMessage the same way you’d attach any other type of file. An even faster way is to right- (or Control-) click the file, choose Share, and then choose Mail, Messages, or AirDrop.
If you’re sending the file to PC users, an MP3 file is more likely to work for them than an AAC file. See the “Understanding Compression” section, earlier in this chapter, for details about the different file types and the ways you can use them.
Some Windows users can play AAC files, especially ones who have iTunes for Windows, which is a free download. For those Windows users, feel free to send an AAC file, which provides better sound in a smaller package than MP3.
If you have any doubt, just send an MP3.