Digital audio formats get improved all the time. Most formats have many versions that we do not go into here. This comparision table is ment to give you a rough idea of the diferences between formats.
Compatible with nearly all software and hardware audio players.
256 Kb/s DVD quality 2mb/1min
128 Kb/s CD quality 1mb/1min
64 Kb/s FM quality 1mb/2min
32 Kb/s AM quality 1mb/4min
16 Kb/s Phone quality 1mb/8min
Metadata
ID3: Title, Artist, Cover Art, Lyrics, Bit Rate
Used by many online services. Usualy free of any restrictions, and can be played, converted, edited with any software.
Originaly developed in 1991 as part of MPEG video format. Widely popular as a non-streaming audio format.
Compatible with many (192) digital audio players including iPod.
format1 Phone quality 2mb/1hour
format2 AM quality 4mb/1hour
format3 FM quality 7mb/1hour
format4 Near CD quality 14mb/1hour
Metadata
Author, title
Requires the Audible file manager or iTunes.
Usualy encoded with Audible DRM
Developed and used exclusively by Audible as part of their online audio book service. Extremely compact format.
Compatible with Apple iPod, Microsoft Zune, Sony PSP, an large number of cellphones from many manufacturers.
format1 Phone quality 2mb/1hour
format2 AM quality 4mb/1hour
format3 FM quality 7mb/1hour
format4 Near CD quality 14mb/1hour
Metadata
Title, Artist, Cover Art, Lyrics, Bit Rate
Can be encoded with Apple's FairPlay DRM.
Used by Apple as part of their online music and audio book service. Used for Podcasts.
Compatible with all CD players.
CD CD quality 10MB/1min
Metadata
CD text:

Title, Artist, Album ,
There's currently no effective DRM scheme for audio CDs.
The original digital audio format. This file format is not used to store audio files on the computer, only for making regular audio CDs that can be played on any CD player.
Compatible with most software and hardware audio players.
WMA Lossless No loss of quality 5-3 mb/1min
128 Kb/s CD quality 1mb/1min
64 Kb/s FM quality 1mb/2min
32 Kb/s AM quality 1mb/4min
16 Kb/s Phone quality 1mb/8min
Metadata
Song Name Title Artist, Genre, Album , Album Art, Parental Rating,
Main format used for PlaysForSure DRM. If encoded with PlaysForSure, needs Windows Media Player 10, and a PlaysForSure compatible portable device.
Developed and supported by Microsoft as part of Microsoft Windows. About same file size as MP3, WMA is said to be better quality. Without DRM encoding can be played by most software and hardware players. With DRM, needs WMP 10, and compatible hardware.
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