Strictly speaking, MP3 specifies how to decode a file and what format
the file needs to be in, but it does not say how to encode it. This
is very interesting and useful. It allows for new (superior) methods
of encoding MP3s while retaining backward compatibility. This also
means that there are variations in quality amongst MP3 encoders (see
What it is Not Good For).
The MP3 specification was created through the cooperation of several
groups. The group that codified the specification and maintains its
as an international standard is the ISO (International
Standards Organization,
each standard is associated with a document number, MP3 is ISO 11172-3
and ISO 13818-3). However,
as is often the case with standards, some company initiated the core
technology for the standard. In the case of MP3 that company is The
Fraunhofer Institute (and
their partners Thomson Multimedia). They began their work within a
project (in 1987) called
EUREKA, EU147, Digital Audio Broadcasting and continued in a join venture
with the University of Erlangen (with professor Dieter Seitzer).
Today, although MP3 is an international standard,
Fraunhofer still hold patents on much of the technology. If another
company wishes to
use MP3 technology, they must pay Fraunhofer a license fee (because
Fraunhofer can demand a high license fee, large companies are
better able to afford the technology than small developers).