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ITunes

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iTunes,是一款由苹果电脑编写的媒体播放软件,用于播放和管理数码音乐、视频文件,或购买FairPlay格式的数码音乐文件。iTunes音乐商店(有时简称为“iTunes”或“iTMS”)是iTunes的组成部分,通过它用户能够透过iTunes购买数字音乐文件。

此播放器以易于使用而著名,但同时仍让用户精确地管理他们的音乐(例如,智能播放列表的功能)。iTunes被用于将歌曲装入到苹果受欢迎的数码音乐播放器iPod中。此程序可以自由下载,同时随Mac OS X和苹果的iLife家庭应用软件包附送。

iTunes兼容的操作系统包括Mac OS XWindows 2000Windows XPWindows Server 2003。过去的iTunes版本支持Mac OS 9,但现在只有使用版本3以下才能支持OS 9。

目录

功能

使用者能够将他们的音乐组成播放清单、编辑档案资讯、烧录 CD 、复制档案到数位音乐播放器、透过它内建的 Music Store 购买音乐、下载 Podcast 、备份歌曲到一张 CD 或者 DVD 上、执行视觉化、为及时配合音乐,表现生动的效果,和编码音乐,成为许多不同的音讯格式。

播放列表

“智能播放列表”是可以被设定为自动更新的播放列表(在线更新),(像一个数据库队列一样)基于一个自定义的列表选择标准。不同的标准可以控制不同方面的播放列表。

播放列表可以随机或按顺序播放。“随机性”乱序算法可以从一张专辑或一位艺术家的不同的音轨中选出不同的音轨进行播放(iTunes 5.0版本中的一个新特性)。派对随机播放也可以从评定等级较高的曲目中选取音轨进行播放。

派对随机播放列表被用作一个简单的DJ助手。默认情况下,它随机的从曲库或其它播放列表里选取音乐;用户可以通过删除其中的音乐来覆盖它的自动选取的结果(iTunes 将选取新的乐曲来替代它们),也可以通过即拖即放或右键菜单添加自己的音乐来达到同样的效果。这样就可以使一个播放列表中同时包含用户预选的和随机选取的音乐。派对随机播放列表可以在运行中提取;这使所有随机选取的音乐在播放列表播放时被替换。

曲库

iTunes 在两个文件中存储关于音频文件的元数据

第一个是名为 iTunes Library 的二进制文件(先前版本中名叫 iTunes x Music Libary),它使用了自己专有的曲库格式。它不仅缓冲类似艺术家和类型这样的存储在音频文件的标记空间(例如ID3标记)中的信息,也存一些像“播放计数”和“采样率”的iTunes特殊信息。

第二个文件名为 iTunes Music Library.xml,它在iTunes中的信息改变时被刷新。它是XML格式的,允许开发者容易的开发像 AppleiDVDiMovieiPhoto 或 Freshly Squeezed Software's Rock Star.Template:Ref一样的可以存取它的信息的软件。

这一系统防止厂商占有对一条音轨的元数据的任何改变,除了“播放计数”、“最后播放”和“采样率”这些被存储在专有文件中的元数据,其它所有信息通过 XML 文件而变得有效。

Internet 广播电台

iTunes 1.0附带了对Kerbango因特网广播电台服务的支持,提供给iTunes用户一个另一个可用的流行在线广播电台流媒体的选择。2001年Kerbango公司推出了商业,苹果公司为iTunes 2.0及其后续版本建立了它自己的网上广播服务。截止于2005年七月,iTunes广播服务已经可以支持大约200到300个不同的“广播站”(网上共有超过400个支持多比特率的流媒体),大多数是MP3流的格式。节目覆盖了许多种类的音乐和谈话,其中包括了像Radio ParadiseDI.fmSomaFM之类的主要的在线广播以及以KKJZWFMUWMVY为代表的地面电台。iTunes同样支持可以用Winamp播放的.pls和.m3u格式的文件,iTunes几乎使用了所有的流媒体格式。

苹果公司目前不再升级Internet广播电台了,iTunes网站上也没有任何消息被提起。

支持文件格式

iTunes目前可以解码MP3AIFFWAVMPEG-4MidiAACApple Lossless格式的文件,以及任何QuickTime可以播放的东西(甚至是视频),包括来自iTunes Music Store的受保护的AAC文件和Audible.com的有声书。为了支持其他如Ogg/VorbisSpeex编码的格式,iTunes需要安装Xiph QuickTime组件。iTunes目前不支持HE-AAC/aacPlus流媒体的回放。HE-AAC/aacPlus格式的文件将像22kHz的AAC文件一样被回放(没有超过10kHz的高频声音)。

曾经有一些关于苹果MP3可变比特率编码器的批评。在2004年的一月,Roberto Amorim组织蒙上双眼的公众聆听测试了六个128kbit/s的编码器,iTunes MP3 VBR 编码器排在了最后。Template:Ref

Windows版本的iTunes可以自动的把WMA格式的文件转换成其它的音频格式,但它不支持直接播放或编码WMA格式。

音乐共享

ITunes Library songs can be shared over a local network using Bonjour (formerly Rendezvous)-Apple's implementation of the Zeroconf (zero configuration required) open network standard—which 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 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.

Originally with iTunes 4.0, 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 EULA.

Music sharing uses the Digital Audio Access Protocol (DAAP), created by Apple for this purpose.Template:Ref DAAP has been reverse-engineered and is now used to stream playlists from non-Apple software.

Just days after the Windows version of iTunes was released, William Zeller, a 20-year-old Trinity College, Connecticut student, wrote myTunesTemplate:Ref, a program which allows Windows users to circumvent the iTunes restriction and download music from an iTunes shared playlist over a network. There also exists a similar open source Java client, called ourTunes. Yet another approach is used by iSyncTunes.Template:Ref This application does not use DAAP and only depends on external interfaces to transfer music between computers. It transfers the songs, saves them on the local hard drive and creates a song list that can be imported into the user's local library. There is also the Blue CoconutTemplate:Ref application for OS X, an AppleScript and Perl client.

视讯

On May 9 2005, video support was introduced to iTunes with the release of iTunes 4.8. Users can drag and drop movie clips from the computer into the iTunes Library for cataloging and organization. They can be viewed in a small frame in the main iTunes display, in a separate window, or full screen. Video support in iTunes is limited: while videos are distinguished from audio in the Library by a small icon resembling a TV or display, they are still grouped with normal music and organized by the same musical categories (such as "album" and "composer"). iTunes is also incompatible with some common video formats, including AVI and WMV.

On October 12 2005, Apple introduced iTunes 6.0 which added support for purchasing and viewing of video content from the iTunes Music Store. iTMS initially offered a selection of several thousand Music Videos and five TV shows including most notably ABC's Lost and Desperate Housewives 24 hours after airing as well as the collection from past seasons; since that time, the collection has expanded with NBC Universal, USA Network, Sci-Fi Channel shows, and Viacom, in addition to further Disney-owned networks' shows. iTMS also gives the ability to view Apple's large collection of movie trailers. Format for purchased Videos is 128 kbit/s Protected MPEG-4 video (H264)1.

As of January 26 2006, iTunes offers over 40 television shows for download, including, most recently, additions from Nickelodeon, Comedy Central and MTV with episodes of episodes of such shows as Spongebob Squarepants, South Park, and Punk'd. Many videos and video podcasts currently require the latest version of Quicktime (7) which is incompatible with older versions of MacOS (only v10.3.9 and later are supported).

视觉效果

iTunes支持可视化和设备插件。视觉效果插件允许开发者建立音乐驱动的视觉效果(iTunes包括一个默认的视觉效果,G-ForceTemplate:Ref,许可证来自SoundSpectrum)。视觉效果插件SDK for Mac 与 Windows可以从苹果网站上免费下载Template:Ref。设备插件允许对附加音乐播放设备的支持,但是苹果将只授权API给那些签署了保密协议的bona fideOEM

Podcast

2005年6月28日发布的4.9版本的iTunes增加了内建podcasting(中文译名“播客”)支持。用户可以在iTunes Music Store或者通过登陆feed URL订阅podcasts。订阅了之后,podcast将被自动的下载。用户可以选择每周、每日、每小时或手动更新podcast。苹果维护了四个“官方的”podcast:Podfinder(Adam Curry)、Street Official Real Talk(采访hip-hop艺术家)、iTunes New Music Tuesday和Apple Quarterly Earning Call。目录的首页同样显示来自商业广播电台和独立玻壳的引人注目的podcast。要获得关于podcasting的资料,请看external links

Video Podcast

iTunes版本6介绍了对video podcast的支持,尽管video和RSS支持已经非正式的存在于4.9版了。用户可以通过iTunes Music Store和feed URL订阅RSS feed。Video podcast不但可以包含可下载的视频文件(MOV、MP4、M4V、MPG),而且可以包括流甚至IPTV。可下载的文件可以传输到新型的iPod上,而且可下载的文件和流可以在苹果新的Front Row媒体中心程序中播放。

同步 iPod 与其它播放器

每当一个iPod与它相连时,iTunes会自动的同步它的音乐与视频库(OS X版本的iTunes可以同步几种不同的数码音乐播放器[1];Windows版本的iTunes只支持iPod[2])。新的曲目与播放列表被自动的复制到iPod上,电脑曲库里删除了的曲目也会在iPod中被删除。iPod中对曲目的评价将被反馈到iTunes曲库里,音乐书将记住最后一次播放的位置。

自动同步可以关闭,以便手动复制单独的曲目或完整的播放列表;然而,iTunes只可以把音乐复制到iPod上却不可以反向进行,这启发了第三方软件支持把音乐从iPod中复制出来。通过一些软件,在Unix命令行也可以做这一工作。

当与电脑相连的iPod没有足够的剩余空间来同步iTunes中的曲库时,将会创建一个与相连的iPod同名的播放列表。这个播放列表可以被用户更改已填充可用的空间。

IPod owners in US markets are taken to a one-time page within the iTunes Music store when first connecting it to their computer. This page currently offers a free album sampler from Lava and Atlantic Records where either the whole album or individual tracks can be downloaded. An album sampler from Universal Records was previously available and may still be accessed via a special link on the web.

ITunes supports a number of other popular portable music players with some limitations, most notably the inability to play music purchased from the iTunes Music Store. Supported players include a number of NOMAD players from Creative Labs, some players from Rio Audio, and the Nakamichi SoundSpace 2 device. Other manufacturers may also offer integration by way of a device plugin.

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, most notably the ml_iPod plugin for Winamp, that allows users to manage their iPod content through Winamp, and provides functionality not available through iTunes, such as the copying of music off of the iPod.

iTunes 音乐商店

Version 4 of iTunes introduced the iTunes Music Store from which iTunes users can buy and download songs for use on a limited number of computers and an unlimited number of iPods. Songs purchased from the iTunes Music Store are copy protected with Apple's FairPlay digital rights management (DRM) system. To date, over 950 million songs have been downloaded since the service first launched on April 28 2003.Template:Ref

Some complain that the tight integration of the iTunes Music Store with iTunes makes the sold music inaccessible to users who use operating systems other than Mac OS X or Microsoft Windows such as the Linux operating system, for which no version of iTunes is available. These complaints have resulted in the development of a number of alternative player software as well as published hacks or workarounds that allow customers of the iTunes Music Store to use the audio software or operating system software of their choice. The most notable of these hacks is PyMusique, which Apple has made several unsuccessful attempts at blocking.

Others complain that their purchased music can only be easily played in iTunes or on an iPod (though they can "burn" the tracks to a compact disc). This has led to the development of software such as Hymn, which decrypts purchased music (from versions of iTunes prior to 6.0) so that it can be played anywhere, or even shared.

Another minor complaint is lack of a recovery facility, whereby users could redownload music files which have been lost. This is a service offered by many of iTunes' competitors, while iTunes only allows "re-authorization" (or ability to recover the license).

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MiniStore

This feature was added in iTunes version 6.0.2. It adds a small window to the bottom of the main window, which can be turned on or off. When the user selects an item in their library, information about that particular item is sent to the iTunes Store, and the MiniStore shows related songs or videos. Initially, the MiniStore caused controversy because people feared it could be used as spyware.Template:Ref Apple clarified that the MiniStore didn't collect any information from users and later made it opt-in.Template:Ref

与其他应用程式整合

On the Macintosh, iTunes is tightly integrated with Apple's iWork suite of applications and the rest of the applications in iLife. These applications can access the iTunes Library directly, allowing access to the playlists and songs stored within. Music files from iTunes can be embedded directly into Pages documents and can supply the score for iDVD, iMovie and Keynote productions. ITunes is also integrated with Front Row (Front Row reads its info from iTunes and iPhoto.) In addition, any song exported from GarageBand, Apple's music-making program, is automatically added to the user's iTunes music library.

iTunes 版本历史

iTunes是从SoundJam MP--Macintosh软件公司Casady & Greene发行的一个流行的商业MP3软件--发展而来的。苹果公司买下了SoundJam MP的版权并且雇佣了创建了SoundJam的三位程序员。iTunes的第一个发行版与SoundJam MP十分相似,增加了CD烧录功能与一个更好的用户界面。苹果已经在iTunes的后续版本中增加了许多重要的功能。

Mac OS 9 以及 Mac OS X

  • 1.0 — 2001年1月9日
    • 最初的发行版本。
  • 1.1 — 2001年2月21日
    • 支持外置刻录机
    • 增强了可视化效果生成器。
    • 支持更多的刻录机。
  • 2.0 — 2001年11月2日
    • iPod 支援。
    • 等化器。
    • MP3 CD 烧录。
    • Crossfader.
    • 音效强化器。
    • 烧录 CDs 速度比原先快了两倍。
    • Unicode元数据和ID3 标签支援。
  • 2.0.2 — 2001年11月16日
    • 支持法语和德语。
  • 2.0.3 — 2001年12月13日
    • Only checked songs are synchronized with iPod.
    • Rio One MP3 player 支援。
  • 2.0.4 — 2002年3月20日
    • 展开 AppleScript 支援。
    • 增强稳定性和性能。

Mac OS X

  • 3.0 — 2002年7月17日
    • 智慧型播放清单。
    • Audible.com 有声书支援。
    • Sound check.
    • 分级。
    • 播放次数。
    • 加入音轨。
    • 导入与导出播放清单.
  • 3.0.1 — 2002年9月18日
  • 4.0 — 2003年4月28日
    • Music Store 支援。
    • Music 共享。
    • AAC 音讯编解码。
    • 专辑插图。
    • DVD 烧录支援。
    • 改进了搜索功能.
    • Beats per minute 栏位。
  • 4.0.1 - 2003年5月27日
    • Music sharing only in subnet.
    • 改进了性能.

Mac OS X 以及 Windows NT/XP

  • 4.1 — 2003年10月16日
    • Voice notes and On-The-Go playlists synchronization with iPod.
    • Support for large library to be burned on multiple CDs.
    • Music Store link dragging and dropping.
    • Music Store now features Audiobooks.
    • Music Store has more advanced Power Search.
    • Music Store 支援定额购买。
    • Music Store 支援礼券。
  • 4.5 — 2004年4月28日
    • iMix
    • 派对随机播放。
    • CD封面打印。
    • Music Store 快速连接。
    • Automatic WMA to AAC conversion (仅限 Windows)。
    • Apple Lossless 音频编码器。
  • 4.7 — 2004年10月27日
    • 支持把照片复制到一台iPod photo之中。
    • Ability to show duplicate songs in your library.
    • 性能改善。
    • iPod preferences now part of the Preferences window.
    • Ability to search iMixes by name on the iTunes Music Store.
    • Taskbar iTunes toolbar, 最小化到系统匣。 (仅限 Windows)
  • 4.7.1 — 2005年1月11日
    • Support for iPod shuffle and "Autofill" functionality.
    • Disallows play and transfer of Music Store-purchased tracks that have had the DRM-protection stripped by third-party applications.
    • Only allows 5 connections per day to libraries shared over a network.


  • 5.0 - 2005年9月7日
    • 精美的外观 (更简洁)
    • 'LCD' display at top now displays artist and song together
    • Ability to group playlists in folders
    • Search now has Search Bar for refining search results. It duplicates the Spotlight bar in Mac OS X 10.4 Finder:
      • 搜寻所有的音乐、有声书、Podcast 和视讯等。
      • 搜寻所有的演出者、专辑和歌曲。
    • 使用 Microsoft Outlook 以及 Outlook Express (仅限连线),自动地同步行事历和通讯录
    • 智慧型播放清单 (with adjustable 'randomness')
    • Support for the playback and creation of Variable Bitrate AAC files
    • Parental Controls to limit children's access to podcasts, the iTunes Music Store, and sharing features
    • Lyrics tab in track info box
    • Each song has the option to remember playback position and to skip it in shuffle mode
  • 5.0.1 - 2005年9月20日
    • 修正 Bug
    • Bonjour for Windows removed from installer bundle after DNS conflict problems
  • 6.0 - 2005年10月12日
    • "视频″增加至来源清单
    • 支援连线经由 iTunes Music Store 购买的视频
    • 可以传输视讯档案到第五代 iPod
  • 6.0.2 - 2006年1月10日
    • First Universal binary 版本
    • MiniStore
    • Multiple speaker streaming
    • Preferred user language (Windows 版本)
    • Stability and performance improvements
    • Fixed Windows 关机/重新开机 interrupt while in "工具列" 模式.

参阅

Notes & references

<references/>

外部连结

Template:Wikibooks

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