One feature musicians appreciate about Apple’s iTunes software and its iPod companion is the ability to load and play back uncompressed AIFF and WAV audio files. This means you can take a stereo copy of the mix you’ve worked on in the studio, load it onto your iPod, and carry it around while you evaluate it. Some musicians even transport multiple tracks between studios using the iPod.
This raises a question: since the software and hardware support uncompressed audio, why do we bother listening to “lossy” MP3 and AAC files at all? As musicians, aren’t we among the first to recognize the compromised fidelity of these file formats? Only one answer really seems to show up: uncompressed audio takes up lots of hard drive real estate. And with the new iPod Mini’s 4GB storage, space is even more limited – you’d get nowhere near the “thousands” of songs promised when using the compressed formats.
With iTunes 4.5, you now have an alternative. Apple has included a new compression format called Apple Lossless Audio Codec (ALAC). Songs imported using the Apple Lossless encoder offer (in theory at least) the same quality as AIFF or WAV, but they take up about half the size (about 5MB per minute of music). Files encoded using ALAC can be played in iTunes, other applications that support QuickTime, and iPods that come with a dock connector. ALAC files have an .m4a extension.
With ALAC there is still trade-off between lossy compressed MP3 and AAC files and the large file sizes (but pristine audio) of ALAC audio, but with file sizes cut in half, it does offer a significant improvement in the usefulness of your iPod.