MP3 — The Day a Standard Got the Name ".mp3"

MP3 is the common name for audio files compressed with the international standard MPEG-1 Audio Layer III. The name was settled on 14 July 1995. Germany's Fraunhofer Institute for Integrated Circuits (IIS), where most of the work was done, held an internal poll and announced in an email that day that the extension for ISO MPEG Audio Layer 3 would be .mp3. Technical development of the method itself had been finished in December 1991, and the standard was published as ISO/IEC 11172-3 in August 1993. The extension came after the standard, and MP3 as a file format spread from there.

Development history is from Fraunhofer's "The mp3 History", publication from ISO, and the naming from Fraunhofer's 2005 press release.

Sending music down a phone line

Fraunhofer's timeline traces the start to the early 1970s, when Professor Dieter Seitzer of the University of Erlangen-Nuremberg worked on sending speech in high quality over telephone lines. When ISDN and optical fibre arrived in the late 1970s and better speech coding seemed less important, Seitzer's team turned to coding music.

In that work a student, Karlheinz Brandenburg, began applying psychoacoustics to audio coding: cutting out what the ear is unlikely to hear in order to reduce the amount of data. In 1988 Brandenburg completed a doctoral thesis on OCF (Optimum Coding in the Frequency Domain), a codec with many of the features of the eventual MP3. In 1987 the university and Fraunhofer IIS had formed a research alliance within EUREKA project EU147 for Digital Audio Broadcasting (DAB).

MPEG's three Layers

MPEG, the working group of the International Organization for Standardization charged with compressed audio and video standards, was set up in 1988. Fraunhofer and its partners proposed ASPEC for the MPEG audio standard, an improved OCF with contributions from the University of Hannover, AT&T and Thomson.

According to Fraunhofer, MPEG received 14 proposals for audio coding, which were merged into four, including ASPEC and MUSICAM. After formal tests MPEG built a family of three schemes: Layer 1, a low-complexity variant of MUSICAM; Layer 2, an optimised MUSICAM; and Layer 3, based on ASPEC. Layer 2, being simpler, was chosen for digital audio broadcasting, while Layer 3, the most efficient and the most demanding, became the key to sending high-quality audio over ISDN phone lines. Technical development of MPEG-1 was finished in December 1991, with Layer 3 offering near-CD quality at less than 2 bits per sample.

The MPEG-1 standard was published as the first edition of ISO/IEC 11172 in August 1993, with audio in ISO/IEC 11172-3. Fraunhofer writes that Layer 3, the most efficient of the three, soon became a popular way to store music on the small hard disks of PCs and to send music files over 28.8 kbps modems.

The email of 14 July 1995

Fraunhofer's 2005 press release "MP3 wird 10 Jahre" (MP3 turns ten) says that researchers at IIS chose ".mp3" on 14 July 1995 as the file extension for the compression method they had developed. The name came out of an internal poll, and an email from Jürgen Zeller dated that day announced that, by the overwhelming view of those asked, the extension would be .mp3. The release describes the naming as the conclusion of years of work by a team of up to 40 people.

In the same year Fraunhofer released a PC-based Layer 3 codec as shareware. Its timeline says that in 1996 it began selling the software over the internet, and that an Australian student bought it with a stolen credit card number and made it publicly available, after which it spread around the world.

From files to players

In 1998 portable players appeared that stored MP3 files in flash memory. Fraunhofer's timeline names Diamond Multimedia's Rio 100 in the US and Saehan Information Systems' MPMAN in South Korea.

The Rio went to court. In its 2001 Napster ruling, the US Court of Appeals for the Ninth Circuit cited its own 1999 decision that the Rio merely made copies to "space-shift" files already on a user's hard drive. It then held that Napster was different, because there the copying also meant distribution to the general public.

Fraunhofer's press release says more than 3 million MP3 players were sold in Germany alone in 2004. Apple's iTunes, released in January 2001, also began as music software that converted songs from CDs into MP3 files on the computer, and led on to the iPod later that year.

The end of patents and licensing

According to Fraunhofer's timeline, Fraunhofer and Thomson set up a joint licensing programme, and companies began licensing MP3 in 1992, directly after standardisation. Fraunhofer says it reinvested about €60 million of the mp3 licensing revenue in research.

That arrangement ended in 2017. Fraunhofer IIS states that Technicolor's mp3 licensing programme, covering certain mp3-related patents and software of Technicolor and Fraunhofer IIS, was terminated on 23 April 2017. Its timeline records under 2017 that the programme ended and that the last core mp3 patent included in it expired.

The same notice says MP3 remains popular with consumers even though more efficient codecs exist, while most streaming and broadcasting services use newer ISO-MPEG codecs such as the AAC family. The iTunes Music Store, opened in 2003, already encoded the songs it sold in AAC rather than MP3.

For the wider story of networks, see the timeline of the internet and the web.