What is iTunes
iTunes is a media player and media library application developed by Apple Inc. It is used to play, download, and organize digital audio and video on personal computers running the OS X and Microsoft Windows operating systems. The iTunes Store is also available on the iPod Touch, iPhone, and iPad. Through the iTunes Store, users can purchase and download music, music videos, television shows, audiobooks, podcasts, movies, and movie rentals in some countries, and ringtones, available on the iPhone and iPod Touch (fourth generation onward). Application software for the iPhone, iPad and iPod Touch can be downloaded from the App Store. iTunes 11 is the most recent version of iTunes, available for OS X v10.6.8 or later, as well as Windows XP or later. It was released on November 29, 2012, one month later than expected, because of a delay by Apple, which said that it needed extra time to get things right.
File Format Support
iTunes 11 can currently read, write and convert between MP3, AIFF, WAV, MPEG-4, AAC and Apple Lossless (.m4a). iTunes can also play any audio files that QuickTime can play (as well as some video formats), including Protected AAC files from the iTunes Store and Audible.com audio books. There is limited support for Vorbis and FLAC enclosed in an Ogg container (files using the Ogg container format are not natively supported) or Speex codecs with the Xiph QuickTime Components, but requires iTunes to run in 32-bit mode (no longer an option after iTunes 11.1.2 released with OS X Mavericks). Because tag editing and album art is done within iTunes and not QuickTime, these features will not work with these QuickTime components. As of Snow Leopard, iTunes 9 (Mac) will play HE-AAC / AAC+ internet streams. The latest version of iTunes (Win/Mac) supports importing audio CDs with the default iTunes standard file format of AAC at 256 kbit/s, but users can choose from 16 kbit/s to 320 kbit/s constant bit rates (CBR) in either AAC or MP3. Importing of audio CDs into MP3 or AAC formats can also be accomplished using variable bitrate (VBR) encoding.
The Windows version of iTunes can automatically transcode DRM-free WMA (including version 9) files to other audio formats, but does not support playback of WMA files and will not transcode DRM protected WMA files. Telestream, Inc. provides free codecs for Mac users of QuickTime to enable playback of unprotected Windows Media files. These codecs are recommended by Microsoft. In addition to importing CDs into the iTunes library, users can also import digital audio files from other sources, an any format that iTunes supports. This can be accomplished by either right clicking on the file, selecting open with, and then selecting iTunes or dragging the file into the open iTunes window. Alternatively, for Amazon.com mp3s, the Amazon MP3 Downloader application will automatically import the mp3 files into the iTunes library.