Audio  Data Compression
	data compression  digital audio  MPEG
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Is the file extension for MPEG, audio layer 3. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 uses perceptual audio coding and psychoacoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal. The stuff the human ear doesn't hear anyway). It also adds a MDCT (Modified Discrete Cosine Transform) that implements a filter bank, increasing the frequency resolution 18 times higher than that of layer 2.

The result in real terms is layer 3 shrinks the original sound data from a CD (with a *bitrate of 1411.2 kilobits per one second of stereo music) by a factor of 12 (down to 112-128kbps) without sacrificing sound quality.

*Bitrate denotes the average number of bits that one second of audio data will consume.

Because MP3 files are small, they can easily be transferred across the Internet. Controversy arises when copyrighted songs are sold and distributed illegally off of Web sites. On the other hand, musicians may be able to use this technology to distribute their own songs from their own Web sites to their listeners, thus eliminating the need for record companies. Costs to the consumer would decrease, and profits for the musicians would increase.

MP3 Resources
Provides numerous resources related to MPEG Audio Layer 3.

MP3.com
Resource site for news and information about MP3. Includes a question and answer section, information about hardware and software, and links to related sites. Updated on Aug 4, 1998

MPEG pointers and resources page
A comprehensive resource for information on MPEG covering FAQs, industry news, audio and video players, systems, companies, products, and shareware. Updated on Aug 1, 1998

32-bit MP3 Players
Collection of reviewed, rated and downloadable MP3 players from Stroud's CWSApps.

Jumbo! MP3
Offers MP3 player reviews, information about encoders/decoders, plug-ins, applications, skins, streaming/broadcasting and FAQs.

LP to CD to MP3
IDG.net article (December 1998) on what MP3 offers, how it's distributed, and the companies involved.

MP3 Articles
Collection of ongoing articles about MP3 from Wired News.

MP3 FAQ
Answers common questions about MP3, with links to related resources.

MP3 Topic Center
CNET article with the latest MP3 news, equipment reviews, and downloads for players, finders, and combo rippers/encoders.

MP3: It's Not Secure, But It's Genuine
IDG.net article (January 1999) on the announcement that Liquid Audio, MP3, CDnow and a collection of record labels and other companies are forming a coalition to watermark digitally distributed music.

MP3now.com
Contains links to the top MP3 search engines and charts, software, hardware, downloads, and overview information.

MPEG Audio Layer 3 (MP3)
Excellent collection of information and resources related to MP3. This site is hosted by mpeg.org.

The Digital Media Association
The Digital Media Association includes other Web-media technology and retail companies, such as a2b music, broadcast.com, CDnow, Enso Audio Imaging, Liquid Audio, RealNetworks, and TCI Music.

WebTools' Complete Tool Kit On MP3
Good collection of overview articles, how-to's and news items.

Yahoo!'s MP3 page
Yahoo!'s directory of MP3. Updated on Aug 4, 1998