iTunes is a proprietary digital media player application, introduced by Apple Inc. on January 9, 2001, at the Macworld Expo in San Francisco. The latest version, iTunes 8, was announced at Apple's September 2008 keynote Let's Rock. The application is used for playing and organizing digital music and video files. The program is also an interface to manage the contents on Apple's popular iPod digital media players as well as the iPhone. Additionally, iTunes can connect to the iTunes Store via the Internet to purchase and download music, music videos, television shows, iPod games, audiobooks, various podcasts, feature length films and Movie Rentals (not available in all countries), and Ringtones (available only in the USA). It is also used to download applications for the iPhone and iPod Touch as long as they are running the 2.0 firmware.
iTunes is available as a free download for Mac OS X, Windows Vista, and Windows XP from Apple's website. It is also bundled with all Macs, and some HP and Dell computers. Older versions are available for Mac OS 9, OS X 10.0-10.2, and Windows 2000. Although Apple does not produce iTunes for other operating systems, it can be run on Linux-based operating systems through Wine, a Windows compatibility layer.
A version of iTunes was shipped with cell phones from Motorola, which included the ability to sync music from an iTunes library to the cellphone, as well as a similar interface between both platforms. Since the release of the iPhone, Apple has stopped distributing iTunes with other manufacturers' phones in order to concentrate sales to Apple's device.
The software that was the basis for iTunes was developed by Jeff Robbin and Bill Kincaid as a media player called SoundJam MP, and released by Casady & Greene in 1999. It was purchased by Apple in 2000, given a new user interface and the ability to burn CDs, had its recording feature and skin support removed, and released as iTunes in January 2001. Originally a Mac OS 9-only application, Mac OS X support was added with the release of version 2 nine months later, and Mac OS 9 support was dropped with the release of version 3. In October 2003, with the release of iTunes 4.1, Apple added support for Microsoft's Windows 2000 and Windows XP. iTunes 7.1, introduced in March 2007 added support for Windows Vista, and 7.4 marked the end of Windows 2000 support. iTunes lacked support for 64-bit versions of Windows until the 7.6 update on January 16, 2008. iTunes currently fully works and is supported under any 64-bit version of Windows Vista (although the iTunes executable is still 32-bit), but not the 64-bit versions of Windows XP or Windows Server 2003; though not supported by Apple a workaround has been discovered for both operating systems.
iTunes is an application that allows the user to manage audio and video on a personal computer. iTunes is officially required to manage the audio of an Apple iPod portable audio player, although alternative software does exist. Users can organize their music into playlists within one or more libraries, edit file information, record Compact Discs, copy files to a digital audio player, purchase music and videos through its built-in music store, download free podcasts, back up songs onto a CD or DVD, run a visualizer to display graphical effects in time to the music, and encode music into a number of different audio formats. There is also a large selection of free internet radio stations to listen to.
Additionally, users can add PDF files to their library (to add digital liner notes to their albums, for example), but the PDFs cannot be transferred to or read on an iPhone or iPod.
In the most recent version, iTunes 8.0, the preferences menu was given a complete makeover. The result added very few new options, but instead removed several options that may seem trivial to most. For example, iTunes once gave users the option to display arrows beside the selected song's title, artist, album, and genre that link directly to the iTunes Music Store. Now these arrows are not removable. Users are now required to import all songs from CDs in the format [tracknumber][trackname], regardless of your personal preferences.
The first is a binary file called iTunes Library and it uses a proprietary file format. It caches information like artist and genre from the audio format's tag capabilities (the ID3 tag, for example) and stores iTunes-specific information like play count and rating. iTunes typically reads library data only from this file.
The second file, iTunes Music Library.xml, is refreshed whenever information in iTunes is changed. It uses an XML format, allowing developers to easily write applications that can access the library information (including play count, last played date, and rating, which are not standard fields in the ID3v2.3 format). Apple's own iDVD, iMovie, and iPhoto, and Freshly Squeezed Software's Rock Star are examples of applications that access the library.
If the first file is corrupted, iTunes will attempt to reconstruct it from the XML file. Detailed third-party instructions regarding this are documented elsewhere. There have been some concerns, voiced by Mark Pilgrim, that this feature will create an "undocumented binary blackhole" because the recovery from the XML file may not work.
It has also been noted that iTunes does not automatically track changes to actual files in the library. If the file is moved or deleted iTunes will display an exclamation mark beside the library entry and the user will need to manually amend the library record. There have been a number of third party tools created to address this problem.
iTunes supports ripping from CDs, but not from DVDs. However, in 2008, Apple and select movie studios introduced "iTunes Digital Copy," a bonus feature on some DVDs that provides a copy-protected, iTunes-compatible file for select films. As with any digital music management, users must use an analog-to-digital converter to import analog recordings (such as audio cassettes) to their iTunes libraries.
The standard list view displays library files with many optional detail fields, including name, artist, album, genre, user rating, play count, and so forth. Item backgrounds alternate between white and a light blue-gray for readability.
The list with accompanying album artwork is much the same, only the list is broken up by albums, with the artwork as a header to the list. Although this allows users to browse content more visually, sorting the list view by name will accordingly break up the library into redundant instances of each album. Accordingly, as with Cover Flow view, the second view mode is most appropriate for users who sort their libraries by album.
Cover Flow displays all of the user's album art as CD covers in a slideshow format. It sorts the albums into artist, genre, etc. Compilation albums are only shown as a single album cover if the compilation tag for each of the album's tracks is turned on. If the song(s) from the album were imported from a 'mix' CD, the album artwork will be displayed as a default music note pictures.
Grid View is similar to Cover Flow, displaying the user's cover art in a grid rather than a side-scrolling format. Albums can also be sorted into groups by artist, genre, or composer.
iTunes also sorts with secondary parameters, album by artist and album by year, to make its artwork-centered interfaces more intuitive.
DAAP allows shared lists of songs within the same subnet to be automatically detected. When a song is shared, iTunes can stream the song but won't save it on the local hard drive, in order to prevent unauthorized copying. Songs in Protected AAC format can also be accessed but authentication is required. A maximum of five users may connect to a single user every 24 hours. The multiple, alternate "View" options normally available to iTunes users including "Cover Flow" are disabled when viewing a shared library over a network.
Library sharing was first introduced with iTunes 4.0, where users could freely access shared music anywhere over the Internet, in addition to one's own subnet, by specifying IP addresses of remote shared song libraries. Apple quickly removed this feature with version 4.0.1, claiming that users were violating the End User License Agreement.
With the release of iTunes 7.0, Apple changed their implementation of DAAP. This change prevents any third-party client, such as a computer running Linux, a modified Xbox, or any computer without iTunes installed, from connecting to a remote iTunes repository. iTunes will still connect as a client to other iTunes servers and to third-party servers.
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 FLAC container format are not supported) or Speex codecs with the Xiph QuickTime Components - because tag editing and album art is done within iTunes and not Quicktime, these features will not work with these QuickTime components. iTunes currently will not play back HE-AAC/aacPlus audio streams correctly. HE-AAC/aacPlus format files will play back as 22 kHz AAC files (effectively having no high end over 11 kHz). HE-AAC streaming audio (which a number of Internet radio stations use) will not play back at all. The latest version of iTunes (Win/Mac) supports importing audio CDs with the default iTunes standard file format of AAC at 128 kbit/s. Users can choose to import CDs from 16 kbit/s to 320 kbit/s constant bit rates (CBR) in either AAC or MP3.
Importing of audio CDs into MP3 can also be accomplished using variable bitrate (VBR), however it has been noted in a double-blind experiment conducted in January 2004 of six MP3 encoders, where the iTunes encoder came last, that the quality of the files produced by iTunes was below par. These results were later refuted because the method of testing using in the experiment was questionable.
The Windows version of iTunes can automatically transcode DRM-free WMA (including version 9) files to other audio formats, but it 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.
AAC and Apple Lossless files support Unicode metadata, stored in the MP4 container as so-called "Atoms". The QuickTime plugin that supports the OGG container format has no support for tag editing or album art.
iTunes uses the Gracenote interactive audio CD database to provide track name listings for audio CDs. The service can be set to activate when a CD is inserted into the computer and an Internet connection is available. Track names for albums imported to iTunes while not connected to the Internet can be obtained later when connected, by a manual procedure. For any album loaded into iTunes for which there is not an existing Gracenote track listing, the user can choose to submit track name data to Gracenote.
On October 12, 2005, Apple introduced iTunes 6.0, which added support for purchasing and viewing of video content from the iTunes Music Store. The iTunes Music Store initially offered a selection of several thousand Music Videos and five TV shows including most notably the ABC network's Lost and Desperate Housewives. Disney Channel's shows were also offered (The Suite Life of Zack & Cody and That's So Raven) 24 hours after airing as well as episode packs from past seasons; since that time, the collection has expanded with content from numerous television networks. The iTunes Music Store also gives the ability to view Apple's large collection of movie trailers.
As of September 5, 2006, the iTunes Store offers over 550 television shows for download. Additionally, a catalog of 75 feature-length movies from Disney-owned studios was introduced. As of April 11, 2007, over 500 feature-length movies are available through iTunes.
Originally, movies and TV shows were only available to U.S. customers, with the only video content available to non-U.S. customers being music videos and Pixar's short films. This is in process of being extended to other countries as licensing issues are resolved.
Video content available from the store used to be encoded as 540 kbit/s Protected MPEG-4 video (H.264) with an approximately 128 kbit/s AAC audio track. Many videos and video podcasts currently require the latest version of QuickTime, QuickTime 7, which is incompatible with older versions of Mac OS (only v10.3.9 and later are supported). On September 12, 2006, the resolution of video content sold on the iTunes Store was increased from 320x240 (QVGA) to 640x480 (VGA). The higher resolution video content is encoded as 1.5 Mbit/s (minimum) Protected MPEG-4 video (H.264) with a minimum 128 kbit/s AAC audio track.
Playlists can also be published by a user of iTunes with his or her own preferences.
Playlists can be played randomly or sequentially. The randomness of the shuffle algorithm can be biased for or against playing multiple tracks from the same album or artists in sequence (a feature introduced in iTunes 5.0, and then discontinued in iTunes 8.0). Party Shuffle can also be biased towards selecting tracks with a higher star rating. With this bias enabled, each star rating increases the preference for that particular song about 4% over that of a one-star-less rated song. Unrated songs are the least likely to be played. Inter-star ratings are stored by iTunes, but only affect this feature in the range of zero to one star.
The Party Shuffle playlist is intended as a simple DJ'ing aid. By default, it selects tracks randomly from other playlists or the library; users can override the automatic selections by deleting tracks (iTunes will choose new ones to replace them) or by adding their own via drag-and-drop or contextual menu. This allows a mixture of both preselected and random tracks in the same meta-playlist. The playlist from which Party Shuffle draws can be changed on the fly; this will cause all randomly chosen tracks to disappear and be replaced.
Version 4 of iTunes introduced the iTunes Music Store (later renamed to the iTunes Store) from which iTunes users can buy and download songs for use on a limited number of computers and an unlimited number of iPods. Many songs purchased from the iTunes Store are copy protected with Apple's FairPlay digital rights management (DRM) system.
At the 2008 Macworld Conference & Expo Apple CEO Steve Jobs announced that the iTunes Store had sold over 4 billion songs and set a new single day record of 20 million songs on December 25, 2007. He also announced that the iTunes Store will offer over 1,000 movies for rental by the end of February. The iTunes movie catalog includes content from 20th Century Fox, Warner Bros., Walt Disney Pictures, Paramount Pictures, Universal Studios, and Sony Pictures Entertainment. Renting a standard definition catalog title will cost US$2.99, while new releases will cost US$3.99. High definition titles will cost US$1.00 more respectively. These movies will also be transferable to all 6th generation iPods. On June 19th Apple stated that they had sold 5 billion songs using the iTunes store.
Users can select podcasts to listen to from the Podcast Directory, to which anyone can submit their podcast for placement. The front page of the directory displays high-profile podcasts from commercial broadcasters and independent podcasters. It also allows users to browse the podcasts by category or popularity, and to submit new podcasts to the directory.
The addition of podcasting functionality to a mainstream audio application like iTunes greatly helped bring podcasting to a much wider audience. Within days after iTunes 4.9 was released, podcasters were reporting that the number of downloads of their audio files had tripled, sometimes even quadrupled.
Podcast listeners can listen in one of two ways: through a hardware device like an MP3 player, or simply on their computer using media player software.
Automatic synchronization can be turned off in favor of manually copying individual songs or complete playlists. iTunes supports copying music to the iPod; however, only music and videos purchased from the iTunes store can be transferred from the iPod back to iTunes. This functionality was added after third-party software was available which allowed users to copy all content back to your computer. It is also possible to copy from the iPod using ordinary Unix command line tools, or by enabling hidden file viewing in Windows Explorer, then copying music from the iPod drive to a local disk for backup. Doing this can be confusing because the files are arranged in such a way that their folders and (depending on iPod and iTunes versions) file names are seemingly picked at random as they are put on the iPod. It is worth noting however that the files (along with their embedded title and artist information) remain unchanged. It is therefore less confusing to let iTunes reimport, reorganize, and rename all of the files after they are backed up. When music or video purchased through the iTunes Store is copied from an iPod, it will only play on computers that are authorized with the account that was used to purchase them. Several third party utilities can remove this limitation by stripping iTunes DRM from protected files. The legality of using such software in the United States is currently the subject of active debate.
When an iPod is connected that does not contain enough free space to sync the entire iTunes music library, a playlist will be created and given a name matching that of the connected iPod. This playlist can then be modified to the user's preference in song selection to fill the available space.
The Mac OS X version of iTunes can also synchronize with a small number of discontinued digital music players, while the Windows version will support only the iPod. The synchronization is limited, however, in that the iPod is the only digital music player compatible with Apple's proprietary FairPlay digital rights management technology, and thus most music purchased through the iTunes Store can only be played on an iPod. The remaining ability to synchronize with a limited number of legacy digital music players is likely a remnant of Apple's timeline the music industry: iTunes was released in January 2001, nine months prior to the iPod's unveiling and slightly more than two years before the introduction of the iTunes Music Store. When iTunes was released, compatibility with other music players was critical; as iPod has become the dominant digital music player, that compatibility may no longer be a necessity.
A number of unsupported third-party programs have been created to help a user of iTunes to synchronize songs with any music player that can be mounted as an external drive. Though iTunes is the only official method for synchronizing with the iPod, there are other programs available that allow the iPod to sync with other software players.
As of iTunes 7, purchased music can be copied from the iPod onto the computer. The computer must be authorized by that iTunes account. iTunes currently allows up to 5 computers to be authorized on one account. It does not allow you to transfer imported music files between computers. This may be necessary to back songs up, transfer songs to a new computer, or restore music after a disk failure using an iPod as the backup source. A number of shareware or freeware applications exist that complement iTunes.
iTunes-managed content can also be accessed via the Apple TV set-top box. Files in the iTunes library can either be synchronized with the Apple TV unit, which results in their being copied to the Apple TV's hard drive, or streamed to the Apple TV directly from a Macintosh or PC. Apple TV does not require the use of iTunes (as of the 'Take Two' software update); it can now import files from the iTunes Store directly over the internet.
Since the release of iTunes 7, Apple no longer promotes the Internet radio feature, and there is no mention of it on the iTunes website. However, it remains in the QuickTime 7.0.4, and iTunes EULA used by iTunes 188.8.131.52. With iTunes 7, the "Radio" item has reappeared as an optional source in the preferences, along with its stations. Companies such as iRADIOmast offer iTunes plugins that add thousands of additional radio stations.
In addition, a user is able to enter their own stream feeds to listen to under the "Radio" tab. This is done by "Advanced" > "Open Stream."