A Comparison of Audio File Formats

Note that this guide isn't meant to be all-encompassing. It is just for the audio file formats which are:

• current
• common
• used for music

There are and will continue to be other formats, including new ones invented as time goes by. While it is true that you could encounter full-length songs in something like .WAV format, this is almost never going to happen.

Format: Advanced Audio Coding ( AAC )

Compression: lossy

What it plays on: iPod, iPhone, Zune, PSP, Nintendo DS1, mobile phones, cross-platform

Meta data: iTunes only

Origin: Apple

Notes: A very broad multimedia standard, popping up in everything from Flash players to video game consoles. It is also known as MPEG-4. Most notably it's the standard of choice for iPods. It's a good compromise between audio quality and file size, with better quality than MP3.

Format: Audio Interchange File Format ( AIFF )

Compression: none (compressed form is AIFF-C)

What it plays on: Mac OS X, iPod

Meta data: Yes, in the MIDI format.

Origin: Apple

Notes: A large file size and a bit structure optimized to work best on Apple hardware makes this format almost unportable to other platforms and not very well-suited for small-storage portable media devices. Consider that one minute of music in AIFF format uses 10 MBs of space, and now think about downloading an album. Usually only used for sound files.

Format: Free Lossless Audio Codec ( FLAC )

Compression: lossless

What it plays on: cross-platform operating systems, much software

Meta data: STREAMINFO

Origin: Xiph.Org Foundation (open source)

Notes: Much more widely deployed and accepted than it's cousin OGG, FLAC is a pretty good standard for lossless audio files which still manages to have a neatly smaller file size. While it is not supported per se on media players, anything more sophisticated than a mobile phone upon which you can install software can play FLAC. Software supporting FLAC includes aTunes (not to be confused with iTunes), Audacity (the world's best open source audio program), MPlayer, and dozens of programs for every platform you can think of.

Format: Flash Video ( FLV )

Compression: lossy

What it plays on: Any Flash-equipped device, cross-platform

Meta data: N/A

Origin: Adobe Software

Notes: This is not an audio format, but a Flash video format. It's worth mentioning here because of the YouTube factor; a common way to obtain songs from the Internet is to use a Flash downloader to rip a song off YouTube, then use a utility program to extract the audio to something like MP3. You can just as easily download and play the FLV files as they are, and treat any Flash player like a media device. Hey, why not?

Format: Monkey's Audio ( APE )

Compression: lossless

What it plays on: Microsoft Windows

Meta data: API

Origin: Monkey's Audio (proprietary company)

Notes: So far, this new lossless format is only operable on computers running Microsoft Windows. Some promises have been made for other platforms and devices, but not much has come through so far. It's still too early to tell.

Format: MPEG-1 Audio Layer 3 ( MP3 )

Compression: lossy

What it plays on: cross-platform, cross-device

Meta data: ID3 metadata

Origin: The Moving Picture Experts Group (AT&T-Bell Labs, CCETT, ISO)

Notes: So massively deployed on Microsoft, Apple, Unix, and other platforms, that it can't be called a media device unless it supports MP3. MP3 provides lower sound-quality than MPEG-4 or AAC, at a slightly smaller file size. The MPEG family of formats achieves smaller file size by cutting out all sound frequencies outside the normal range of human hearing.

Format: Vorbis ( OGG )

Compression: lossy

What it plays on: Google Android phones, some rare media players, scattered systems

Meta data: Vorbis comment

Origin: Xiph.Org Foundation (open source)

Notes: For being an open source standard alternative to the MPEG format, this is an incredibly unsupported format. It seems that almost nothing plays it "out of the box", but some devices can play it with a plug-in that you have to (a) find, (b) install, and (c) maintain yourself. While other open source file formats and standards have enjoyed relatively great success, don't expect OGG to stick around for long. Even the most die-hard Linux zealot doesn't seem to like OGG.

Format: RealAudio ( RA )

Compression: lossy

What it plays on: RealPlayer, Internet

Meta data: Real Audio Metadata (RAM)

Origin: RealNetworks

Notes: You're unlikely to encounter this format in straight-forward music downloading; instead it's used for streaming audio. Thanks to RealNetworks' tightly-locked proprietary nature and the bad reputation of their software, this format is becoming increasingly rare.

Format: Windows Media Audio ( WMA )

Compression: lossy (lossless in WMA-9)

What it plays on: Zune, Windows systems, cross-platform,

Meta data: ASF container format

Origin: Microsoft

Notes: Microsoft being the 800-pound gorilla that it is, any media device that is connected to Microsoft better handle the WMA format or else. However, Apple is laughing at it and rightly so. The FFmpeg project is a group which reverse-engineered this format so that it can now play on Unix/Linux/POSIX systems, oppening the door to future non-Microsoft mobile support. Adobe software also supports it. The quality is slightly less than the MPEG family of codecs, the file size is slightly larger, and it may have the dreaded "PlaysForSure" DRM mixed into it.

Footnote: Why can't we have one standard format?

Wouldn't it be a nice world if we just had ONE audio file format, and not have to bother with all of this? The thought just brings tears to your eyes, doesn't it?

But nothing seems to abhor a standard like technology. From text to image to audio to video, we seem to be up to our ears in mutually incompatible file formats. It's been this way since the very first computers arrived on the scene, and it's probably never going to change. To soothe your aggravation, here's some reasons on why that is:

Nobody is forcing them to standardize. There isn't any world-wide government enforcing a standard. International organizations do recommend standards, but they often get ignored. These include the Telecommunication Standardization Sector (ITU-T) of Geneva, the non-profit International Electrotechnical Commission (IEC), and the International Organization for Standardization (ISO).

Competition. Given a choice between an absolute monopoly and a bunch of competing companies, we want to choose the competitive market. What happens when company A uses the format produced by company B is, it makes it easier for company B to compete. So company A goes off and does its own thing, and everybody else does their thing, and so we have a stew of formats. In some cases, patent-free and open formats have been created by the open source community specifically to fight back against a format controlled by a monopoly.

Everybody's trying to make a profit. So they patent their formats and patent their devices, and if you have a problem hopping from platform to platform, that's your fault for not being loyal to one company.

Improved formats are always being invented. Here, at last, is one positive reason. Technology is always advancing, so we have either better ways of encoding audio data, or better devices that can handle higher-quality data. A lot of what you see in the glut of audio file formats is legacy formats that still exist from platforms a decade old or more.

There, hopefully this at least puts to rest the nagging suspicion you've been having that the tech companies are creating dozens of different file formats just to drive you crazy. That's actually only part of the reason.