All About Format Audio Part 1

Posted on Thursday, March 19, 2009 by khabibkhan

Playing back digital audio has turned into a regular experience for most computer users thanks in part to a variety of formats that helped make audio smaller in size, allowing simple methods of digital distribution. There are many different formats that serve many different purposes. Need to know FLAC from MP3? We’ve broken down each format and its main purpose in this audio formats primer.


The most popular audio format, and the one that largely changed music as we know it, is called MP3. MP3 is a relatively old format and part of the first set of MPEG specifications governing the playback of both audio and video. MP3 actually stands for MPEG1 layer 3, and because of the name some people often confuse it with the audio/video standards MPEG-2 and MPEG-4.

MP3 is a lossy codec, which means when files are encoded to MP3, the encoder chooses which parts of the audio are most important, and discards other less important parts. This process results in audio files that are passable, but less complete than the original file. Depending on the bitrate at which the file is encoded, more information can be kept or thrown out. This “lossy” nature, like all MPEG codecs, makes it an ideal candidate as a delivery format, meaning a format for mass consumption, rather than an archival format. MP3 doesn’t have any sort of digital rights management (DRM) built-in, meaning most MP3s can be transferred to any device and be expected to play.


MP3’s ideal successor is AAC, which stands for Advanced Audio Codec. AAC was largely designed to be the next version of MP3, and accomplishes things like better quality audio at similar bitrates. That means AAC will sound better than similarly sized MP3s. While AAC might be the successor to MP3, thanks to MP3’s 10+ year lifespan as a file format, MP3 is supported with most devices whereas AAC doesn’t have the breadth of support in hardware devices by comparison. However, that’s not to imply that AAC doesn’t have a broad install base. Most notably, iPods can play AAC files back natively, and every track purchased in the iTunes Music Store is an AAC file.

Unlike MP3, AAC has seen some DRM implementations, again most notably in the iTunes Music Store. While not defined as part of the AAC specification, Apple has forked AAC to try to thwart music copying. The implementation, known as FairPlay, requires listeners to be using iTunes, and have a computer authorized to play the music before being able to actually listen to the files. Apple limits the computer count to five total activated iTunes accounts at a time (check out our guide to deauthorizing all those iTunes accounts at once if you ever hit your limit and find the need).


Another lossy audio format is the OGG format. OGG is a “free” format, meaning the format is maintained by the not-for-profit foundation, and doesn’t charge for licensing or implementation. OGG is a file format popular with open source computer users, since there is no corporation sponsoring the format and all of the format’s specifications and encoding methods are open and public. OGG is a less popular format, one not sanctioned by any store selling legal tracks, however many users transcode their music collections into OGG typically using the compression format called Vorbis. OGG files do not typically have any implementation of DRM, since the idea of DRM is counterintuitive to the nature of open source.