iTunes can convert a song from one format to another. For example, you can convert a song from a WAV file format to an MP3 file format.
How to convert a song
- From the iTunes menu, choose Preferences.
- Click the Importing icon.
- Choose the encoding format that you want to convert the song(s) to from the Import Using pop-up menu. (See the "About compression" section below.)
- Click OK to save the settings.
- From the Advanced menu, choose Convert To (AIFF, MP3, or WAV depending on the preference you chose in step 3).
- Choose the song, folder, or disk that contains the songs you want to convert. If you choose a folder or disk, all the songs it contains will be converted.
When you convert a song, some data may be lost due to the way certain formats compress data. For this reason these formats are sometimes called "lossy" formats. The advantage of using a "lossy" format is that the file sizes are much smaller, which means you can store more songs in the same amount of disk space. The disadvantage is that the sound quality may not be as good as the original, uncompressed format. Depending on the song, the speakers or headphones, and the player you use to play the song, you may not be able to tell the difference between a compressed "lossy" song and a song that is not compressed.
Once a song is compressed (meaning some of its data is lost) you cannot retrieve the data by uncompressing it. If you convert a song from a "lossy" format to a uncompressed format, the quality of the song will not improve and the file will only take up more disk space. For example, if you convert a song in MP3 format (a compressed format) to AIFF (an uncompressed format) the song will take up much more space on the hard disk, but it will still sound the same as the compressed file. In order to take advantage of uncompressed formats you should only import songs using these formats.