MPEG Layer 3

page type::article thing type::file type purpose::audio compression::lossy

About
MPEG Layer 3 (MP3) is a lossy compression format for audio data. Files encoded in this format use the .mp3 file extension and are often referred to as "MP3"s.

Many organizations, most notably the Fraunhofer Society, have claimed software patent(s) on technology used in the MP3 format, and anyone wishing to release (a) software or hardware supporting MP3 audio, or (b) content encoded in the MP3 format must obtain permission from the patent owners (usually in the form of a paid license).

Because of this restriction, significant effort has been put into developing free alternatives, most notably Ogg Vorbis, and free software often does not support MP3 directly due to license conflicts.

The various MP3-related patents expire on dates ranging from 2007 to 2017 in the US, and at other times in other countries.

Reference

 * MP3 Licensing official site
 * Fraunhofer IIS division MP3 page
 * Fraunhofer IIS division MP3 page