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Key Terms

Key Terms

Don't let unfamiliar terms discourage you from learning all you can about the iPod and iTunes. If you don't completely understand what one of these words means, flip to the indicated page, read the full definition there, and find techniques related to that term.

Advanced Audio Coding(AAC)

A new digital audio format co-developed by Apple as part of the MPEG-4 definition; AAC has better quality than MP3, as well as optional built-in DRM. Page 8

AirPort Express

One of Apple's brand of wireless Internet connectivity devices, a wireless base station that provides not just wireless (802.11g) connectivity but also an audio connection between iTunes and a set of speakers to which it's connected. 229


A feature of AirPort Express that broadcasts the capability to route music to a set of externally connected speakers to any copy of iTunes running on the network; any of these iTunes computers can choose the AirTunes speakers and play music through them wirelessly. 229


The digital equivalent of the spoken-word tape. It's a special kind of digital audio file that plays for a long time as its content (the text of a book or speech) is read. The file includes additional technology such that, if you pause listening to the audio stream, iTunes remembers where you left off and picks up again at that point when you resume listening. This technology even works if you move from iTunes to iPod as you listen to the audiobook. 94


Register a computer over the network to be able to play protected AAC files purchased using a particular iTunes Music Store account. 103


A technique for selecting just enough songs at random from a specified source to fill your iPod shuffle to capacity. With one button click, you can copy a whole new set of music to the device. 171

Bit rate

The number of bits per second consumed by an audio stream; the bit rate can be constant or variable, and if constant can be used to calculate how much disk space a song file will take up. 52

Broken pointer

A song entry in the iTunes database that points to a file that no longer exists or has been moved to another location so that iTunes can't find it. Broken pointers are marked with a ! icon. 242


To create a music CD using a writable disc (CD-R, CD-RW, or writable DVD). Page 3


A CD or DVD drive capable of creating written, or burned, discs as well as reading them. Most modern computers are sold with CD burners, and many come with DVD burners as well. 204


Writable compact disc. A CD-R can be burned once, and after that its contents cannot be changed. A CD-R or CD-RW can hold 650 or 700 megabytes of data, depending on the format. 204


Rewritable compact disc. A CD-RW can be burned multiple times, usually up to a few dozen times. 204

Compact Disc Digital Audio(CDDA)

The standard specification for mastering compact discs, which includes a specific format for the uncompressed audio data in each track. 202


Fitting more music into a fewer number of bytes by discarding unimportant musical data or indexing repeated patterns. 51


Having one track fade out at its end; the next track begins as the previous one is still fading. 159


Revoke the ability for a computer to play protected AAC files purchased using a particular iTunes Music Store account, freeing up one of the available authorizations. 103

Deep discharge

Battery characteristics where optimum longevity and performance result from discharging the battery completely before recharging it. 197

Digital Rights Management(DRM)

Software algorithms that provide “copy protection” for digital music, usually enforced with digital “keys.” 12


Writable digital versatile disc. A DVD can hold 4.7 gigabytes of data and generally costs significantly more than a writable CD. Data on a DVD is heavily compressed, making the format much more complex than that of a CD. Some DVD formats, such as DVD+RW and DVD-RW, can be written to more than once. 204


A physical connection to a LAN is done using Ethernet, a low-level communication protocol that involves cables that end in RJ-45 jacks, which resemble large phone jacks. All modern Macs have an Ethernet port, which runs at 10, 100, or (on top-end models) 1000 megabits per second. Page 229


The specific internal data structure of a digital music file. 51


A playlist of music from the Music Store that you create in iTunes and then publish to the Music Store's servers. 111

Info tags

Data fields built into a digital audio file that contain the song's title, artist, album, track number, album art, and other information. Often called ID3 tags in MP3 files; also referred to generically as metadata. 11


A compression or conversion process where perfect sound quality from the original source is preserved. Lossless compression doesn't achieve such small file sizes as does lossy compression, but it's reversible. 52


A compression or conversion process in which some sound information or resolution is irretrievably lost, as when encoding a CD to MP3 format. The converse is lossless compression, meaning a reversible process in which no information is lost. 52

MPEG-1 level 3(MP3)

The most widely used format for digital music, MP3 files sound pretty good but have no copy protection built in. 11


An online financial broker that makes it easy for money to be exchanged between any two parties, found at http://www.paypal.com. 91


A collection of songs created by the user in a specific order, usually gathered according to a desired “theme” (such as “Driving Tunes” or “Workout Mix”). 140


Gray “arrow” icons in song info fields in iTunes that lead to similar music in the iTunes Music Store. 107


Apple's multimedia technology, built into Mac OS X; it must be installed on Windows for iTunes to work. 30

Really Simple Syndication(RSS)

A mechanism for a dynamically updated series (or feed) of items, such as in a blog or “latest news” site, that are delivered to a specialized application for quick and easy perusal. Page 125


To copy or import audio data from a CD. 3

Scrub bar

A long, horizontal control with a sliding knob that allows you to skip directly to a specific point in the timeline of a music or video file, as well as showing you your current position in the timeline. 19

Shallow discharge

Battery characteristics where optimum longevity and performance result from keeping the battery's charge “topped up” at all times and preventing the charge from running down all the way. 197

Smart Playlist

A playlist automatically created from user-specified criteria that is updated to reflect new music you add that matches those criteria. 142


To connect your iPod to your computer so that the iPod is filled with all the music in your iTunes library, with all the up-to-date info tags and playing history; iTunes is similarly updated to match the information on the iPod's songs. 164


A program within iTunes that displays colorful patterns, responding visually to the playing music by creating agitated wave shapes in constantly changing forms. 151

Windows Media Audio(WMA)

Microsoft's competitor format to AAC, WMA files are similarly higher-quality than MP3s, but their DRM is more restrictive. 8

Wireless base station

A networking device that enables you to share a broadband connection within a household by allowing computers with wireless capabilities to connect to it and share its connection. 229



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