Which File Format Should You Use?

When it comes to ripping music from a CD to your computer's hard drive, you have to choose which file format and bit rate to use. As you've just discovered, there are a lot of choices.

Of the compressed formats, the MP3 format is the oldest and most universal; almost every music player program and portable music player is MP3-compatible. You can play MP3 files on an Apple iPod or iPhone, and with both the iTunes and Windows Media Player programs. That makes it a very good choice for most users.

The two other primary compressed formats present some compatibility issues. The WMA format was developed by Microsoft and is used by most commercial online music stores (except for the iTunes Store); it's compatible with all music player programs except Apple's iTunes, and with all portable music players except Apple's iPod. Obviously, this is the default format used in Microsoft's Windows Media Player program.

The AAC format is used by both iTunes and the iPod and iPhone; however, it's not compatible with many other music player programs and portable music players. That said, DRM-free AAC files can be played in Windows Media Player 12, and they show up in WMP's default Music library.

Note Previous versions of WMP could not play AAC files. AAC compatibility is a new feature of WMP 12-which for many users is reason enough to upgrade.

If you're downloading music from an online music store, you probably don't have a choice of formats; you have to take the music in the format that it's in. Practically, that means if you have an iPod or iPhone and use the iTunes Store, you'll get your music in AAC format. If you have any other type of player (such as the Microsoft Zune or Creative Zen) and get your music from any other online music store (such as Napster or the Zune Marketplace), you'll get your music in either WMA or MP3 format.

When you're copying files from your CD to your PC, however, you have your choice of format. For compatibility with all portable music players (including the iPod), use the MP3 format. If you have an iPod and don't care about playing your music on other portable music players, you can use the better-sounding AAC format. Or if you have a non-Apple player and never want to play your music on an iPod, you can use the equally good sounding WMA format.

And here's another consideration: What if you want to play your digital music not on a PC or portable audio player, but rather on your home audio system? Neither the AAC, MP3, nor WMA formats have goodenough audio quality to sound good when played through a quality home system. In this instance, you can save your files in WAV format, although that will take a lot of disc space-about 650MB per CD. A better alternative is to use a format that incorporates lossless compression, such as WMA Lossless (for Windows PCs) or AAC Lossless (for compatibility with the iPod). These formats reproduce the exact sound of the original, with no deterioration in audio quality, but at a smaller file size than the noncompressed WAV format. (Lossless files are larger than compressed AAC, MP3, or WMA files, however.)