When you rip songs from CD in iTunes, you can choose what file format you want the songs to be saved in. Different file formats have different strengths and weaknesses – generally trading the size of the resulting file for the sound quality of the music.
The two most common file types in iTunes are MP3 (Definition) and AAC (Definition), though iTunes also offers Apple Lossless Encoding, AIFF, and WAV (these last two are high-quality, uncompressed file types used for CD burning. Avoid using these in iTunes unless you really know what you’re doing and have a good reason).
AAC files are generally higher quality and slightly smaller than MP3 files of the same song. The reasons for this are fairly technical (more about the specifications of the AAC format can be found at Wikipedia), but the overview of the reasoning is that AAC was created after MP3 and it offers a more efficient compression scheme, with less quality loss, than MP3s. Despite popular belief, AAC was not created by Apple and is not proprietary to Apple or its devices. AAC can be used with a wide variety of non-Apple devices.
AAC is less widely supported than MP3, partly because it's newer and partly due to the rise of Windows Media due to Microsoft's prominence.
AAC is the native file format for iTunes, but for the reasons stated above, you may not want to use it. Here’s a guide to deciding what file type you’ll want to use in iTunes.
Once you’re done reading this, check the step-by-step guide to changing iTunes settings to use the file format you want.
Small file size
Higher quality sound than MP3
Less compatible; Works in iTunes and with iPod, on Microsoft's Zune, and on the Sony Playstation 3 and Playstation Portable, as well as some cell phones
Small file size
More compatible: works with virtually every portable audio player and cell phone
Lower sound quality than AAC
Highest quality sound
Less compatible; Only works with iTunes and iPod
Larger files than AAC or MP3
If you plan to stick with iTunes and an iPod for a long time, go with AAC (for more, check out my side-by-side file format listening test). You can always convert AACs to MP3s using iTunes if you decide to switch to a device that doesn't support AAC (though bear in mind that doing this will reduce the quality of the converted file). In the meantime, though, your music will sound good and you’ll be able to store a lot of it.
Other iTunes Articles
- 4 Ways to Use Multiple iPods on One Computer
- Using Multiple iTunes Libraries on One Computer
- 7 ways to merge iTunes libraries from various sources
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