Apple Lossless file format size

Q: How much more space do Apple Lossless files take up than MP3s?  Is the sound quality that much better?  I am trying to decide between an iPod mini and a 20 or 40 GB iPod.

– Jim

A: Apple Lossless files take up anywhere from about 1/3 to 1/2 the size of the original music files; this means that a one-hour CD, which takes up about 600 MB, will occupy from 200 to 300 MB in Apple Lossless format. The reason the file size can differ is because the efficiency of Apple Lossless compression varies according to the data density of the music.

This is similar to using mild ZIP compression for files; some compressed files may be as much as 90% smaller than the originals, whereas others may only be 50% smaller.

As for the sound quality: lossless compression, as its name suggests, loses none of the original information encoded in the music files. It is as good as the original CDs.

However, you should try encoding in AAC or MP3 format at high bit rates (the maximum is 320 kbps) to see if you can hear the difference; even if you are sensitive to sound quality, it is very possible that you won’t hear the difference between, say, an AAC file at 256 or 320 kbps and the original CD. If you’re going to use inexpensive headphones with your iPod – like the ones that come in the package – you may not hear any difference between a 160kbps file and the original.

Kirk McElhearn is the author of several books including iPod & iTunes Garage.