AAC (Advanced Audio Coding) A small-file, high-quality encoding format. Used by XM satellite radio and iTunes.

Aggregators (readers, clients) Web-based programs that collect and display the feeds you subscribe to. They may also download the feeds.

Audioblog Similar to a (print-based) Web-log, but most of the content is audio.

Bandwidth How much data can be transferred in a given period, usually expressed as bits per second (bps).

Blog (short for weblog) A Web site on which individuals or groups regularly post their opinions, diaries, and/or information.

Bit The most basic unit of information. A bit is either “on” or “off”—states that are represented by a one or a zero.

Bit rate The rate at which data is transferred. The most common bit rate for MP3s is 128 Kbps (kilobits per second).

Byte A byte is a set of 8 bits, enough to hold one character of alphanumeric data.

CBR (Constant Bit Rate) A file compress-ion rate that does not vary. (See VBR).

Codec (compressor / decompressor) An algorithm that converts data from analog to digital and back. (See compression.)

 

MB Megabyte(s), one million bytes (in fact, 1,048,576 bytes)

MP3 (MPEG-1 audio layer 3) is a lossy audio-compression format that can reduce files to as little as one-tenth of the size of the original.

MPEG-4 Audio and video coding standards for broadcast television, streaming audio, and other mediums.

Narrowcasting The wide distribution of very specific content.

Podcatchers Podcast aggregators, often for specific podcasts.

Podjack To create an alternate RSS feed for a podcast without the permission of the owner.

Protocol A set of rules that describe how data is transmitted between computers.

Quickcast Five-minute-or-less podcast.

Rip To copy and compress audio tracks.

RSS (Really Simple Syndication, Rich Site Summary) The most popular type of feed for podcasting.

Sampling An analog signal is measured at precise intervals and encoded as numbers (converted to digital). The sampling rate is how many times per second it is read. (CDs sample 44,100 times a second.)


A small flash-memory podcast player
Small flash-memory podcast player (self-knotting cord is standard equipment)

Compression The reduction of file size by omitting some of the information. This is usually done by removing frequencies that the ear cannot hear. (See lossy.)

DAP Digital audio player.

Feed (channel) A list of files that describe the contents of podcasts (or text pages). You can use the feed's address to subscribe to the contents.

Flash memory stores information on chips. Most small digital-audio players have flash memory. Flash is easy on batteries and does not require moving parts. Used in digital cameras.

Formats Files are saved in formats, such as MP3, wav, mpg, and AAC.

Frequency This is the rate at which a sound vibrates. It is stated in Hertz (Hz), which is cycles per second.

GB Gigabyte(s), one billion bytes (in fact, 1,073,741,824 bytes)

HD radio transmits compressed CD-quality sound over FM channels (or FM quality over AM). HDR is still experimental, and the receivers are still expensive. Happily, it will not require a subscription.

Kbps Thousands of bits per second, a measurement unit for data transmission.

Lossy compression causes some of the original data to be thrown away (e.g., MP3 music or jpeg photos). Files created with lossless compression can be completely recreated from the stored information (e.g., zip files, tiff photos).

Speedcast An experiment in reducing podcast length. Speech is faster but the pitch remains the same.

Streaming The on-line equivalent of an on-air broadcast that can be launched at any time. It is not stored in your computer, as podcasts are, but simply plays through it.

Syndication is the supplying of content for publication in more than one place, as, for example, comic strips in newspapers. Most syndicated podcasts are free.

Tag A word or phrase that characterizes a digital file to make it easier to find something specific. For example, a photo of the Acropolis might have such tags as Athens, Parthenon, architecture, Greece, and real old building.

Time shifting The use of a device such as a TiVo to record something to be seen or heard when you feel like it.

VBR (Variable Bit Rate) A compression rate that adjusts to fit the properties of a file. For example, part of a podcast may be music, or part of a song may have a lower volume. At that point, the bit rate may be adjusted to a more appropriate level. (See CBR.)

Videoblog (video weblog, vlog) Similar to a (print-based) weblog, but with video.

Vodcast (vidcast, vcast) A video podcast.

XML (eXtensible Markup Language) A programing language that makes it possible to send some kinds of data over the Internet. XML is used for RSS.