Audio file formats at a glance

[Revan]

The first format or codec to gain widespread acceptance was MP3, but there are now a variety of players on the market that support AAC, WMA, OGG, and other formats. This table will help you sort out the alphabet soup and determine which codecs you need in an MP3 player.


AA Audible, the format used by Audible.com, is designed for spoken audio content such as audiobooks and talk radio programs, including NPR. Many portable music players support AA.

AAC Advanced Audio Coding, developed by Dolby Laboratories and best known as the format used in iPods. Apple and Real use their own DRM (digital rights management) technology to secure AAC downloads for iTunes and Real Rhapsody. The iPod is the solitary player that accepts copy-protected AAC files and only those from iTunes Music Store.

ATRAC3 ATRAC3 and ATRAC3plus are lossy compression formats used by Sony and its squadron of Network Walkman MP3 and MiniDisc players. It is an efficient format that sounds better than MP3 at the same bit rates. This format is akin to WMA and AAC but is generally known as a dark horse, as it is used by only Sony-branded players. Music downloaded or streamed from Sony's Connect music store are ATRAC3 files.

FLAC Free Lossless Audio Codec, an open-source format that uses a clever algorithm to preserve every 1 and 0 found in the uncompressed file. Though not widely implemented, lossless formats such as FLAC are popular with audiophiles who disdain "lossy" formats (MP3, WMA, and so on) that further compress files.

MP3 Motion Pictures Experts Group Layer 3 is such a mouthful, it's no wonder the abbreviation has taken over. In fact, MP3 is the Kleenex of digital music--so common, it's become shorthand for all portable players whether they use this format, though nearly all do. The eMusic online music store and most file-sharing networks use MP3.

MP3Pro The latest from Thomson/RCA (the company that licenses MP3 to manufacturers and developers), MP3Pro sounds better than MP3 at the same bit rate. However, it hasn't been widely adopted by manufacturers other than RCA.

OGG Ogg Vorbis is the underdog of this group. It sounds great, and because it is open source, there are no licensing fees when it's used to encode or play music--a fact that probably makes developers of other codecs a bit nervous. Although it's not as widespread as AAC, MP3, or WMA in players or online music services, OGG could gain traction as consumers grow more sophisticated in their digital audio usage and developers look for ways to cut down on licensing costs.

WAV/AIFF This is uncompressed audio, like what you'd find on a standard audio CD. For the most part, WAVs are found on Windows machines, while AIFFs live on Macs.

WMA Windows Media Audio, Microsoft's format, sounds better than MP3 at the same bit rate. Some WMA files include copy protection, but others do not (if you left the "Copy protect music" box checked under the Options menu in Windows Media Player you've been ripping copy-protected WMAs). Most players support WMA, and online music stores such as Napster and Wal-Mart use secure WMA.