1987

the audioteam 1987 (from left): Harald Popp, Stefan Krägeloh, Hartmut Schott, Bernhard Grill, Heinz Gerhäuser, Ernst Eberlein, Karlheinz Brandenburg und Thomas Sporer

1987: A research alliance is formed between Erlangen-Nuremberg University and the Fraunhofer Institute for Integrated Circuits within the framework of the European Union funded EUREKA project EU147 for Digital Audio Broadcasting (DAB). Led by Prof. Heinz Gerhäuser (Fraunhofer IIS), the joint research team puts up a functional real-time codec of the LC-ATC (Low Complexity Adaptive Transform Coding) algorithm as the basis for its research. Up to that point, LC-ATC existed only as a simulation on computer. Due to the enormous computing time required it could be tested only with a very limited amount of audio material. The real-time codec enables testing LC-ATC under real-world conditions and leads to significant algorithmic optimizations. The hardware system comprising multiple Digital Signal Processor (DSP) modules and a number of audio and data I/O interface cards is developed by a group of scientists including Harald Popp and Ernst Eberlein.

1988

1988: The Moving Picture Experts Group MPEG is established as a working group of the International Standardisation Organisation ISO. It is in charge of developing compressed digital audio and video standards.

1989

1989: Brandenburg finishes his doctoral thesis on the OCF algorithm (Optimum Coding in the Frequency Domain), a codec exhibiting a number of characteristics of the eventual mp3 technology, like a high frequency resolution filterbank, non-uniform quantization, Huffman coding, and its side information structure. The software part of the real-time system for OCF is mainly developed by Bernhard Grill under the lead of Prof. Gerhäuser. In this phase, the basic OCF technology is extended towards a system that is capable of coding audio signals at 64 kBit/s in good quality for the first time worldwide. That way, transmission of music in real-time over telephone lines could be achieved.

1991

1991: A new high-performance audio codec called ASPEC (Adaptive Spectral Perceptual Entropy Coding) codec is presented as the result of further improvements of OCF and contributions by Hannover University, AT&T, and Thomson. The development partners had proposed ASPEC already in 1989 for the forthcoming MPEG audio standard.
MPEG in total received 14 proposals for audio coding. Encouraged by MPEG, the audio coding contributions are merged into four proposals including ASPEC and MUSICAM. After several formal tests, MPEG suggests to erect a family of three audio coding schemes from MUSICAM and ASPEC: Layer 1 is a low complexity variant of MUSICAM, Layer 2 an optimized version of MUSICAM and Layer 3 is based on ASPEC.
Due to its lower complexity, Layer 2 is selected by DAB as the audio format for digital audio broadcasting services whereas the ASPEC / Layer 3 coder with its highest coding efficiency known at that time (and higher complexity) becomes the key to transmitting high quality audio via ISDN phone lines. As a proof of concept, Fraunhofer IIS manufactures and sells a number of ASPEC 19” studio racks to professional users such as radio stations. In this way, transmitting speech and music reliably via ISDN between broadcasting studios becomes the first real application of the Fraunhofer IIS audio coding algorithms.

The evolution from ASPEC to the final "mp3" (MPEG-1, Layer 3) codec involves some technological harmonization with the other planned MPEG-1 audio coders and the addition of a joint stereo coding mode, the latter developed by Jürgen Herre. In December, the technical development of the MPEG-1 standard is finished. Layer 3 offers near CD quality at less than 2 bits/sample.

1992

1992: MPEG concludes its first compression standard, MPEG-1, for use in video CDs (CD-I); the first edition is released as ISO/IEC 11172 in August 1993. In its audio section, a generic family of three codec formats (Layer 1, 2, 3) is specified. Being the most efficient of the three codecs, Layer 3 soon becomes a popular way to store music on the relatively small hard disk drives of PCs and to transfer music files over the Internet through 28.8kbps PC modems.

1994

1994: The first generation of one-chip mp3 decoders by Micronas are introduced.

1995

1995: The name “mp3” is coined. In an internal poll, Fraunhofer researchers unanimously vote for .mp3 as the file-name extension for MPEG Layer 3. In the same year, Fraunhofer provides a first PC based Layer 3 codec as shareware.

1996

1996: Worldspace Radio chooses mp3 for audio coding.

1997

1997: Michael Robertson starts mp3.com as a web site for information about mp3 technology, encoder, player, and anything else related to mp3. Not long after that, mp3.com was the biggest legal mp3 music sharing service.

1998

1998: The era of portable mp3 listening begins with the introduction of Diamond Multimedia’s "Rio 100" in the U.S. and Saehan Information Systems’s "MPMAN" in Korea. They are the first portable players using solid-state flash memory to store and play compressed mp3 music files either downloaded from the Internet or encoded from a music CD.

2000 - 2006

The increasing popularity of mp3 portables triggers dozens of companies to launch similar portable devices for compressed music playback, and stimulates the development of additional audio codecs for use in PCs and consumer electronics.
2000: In the U.S., the first portable audio devices equipped with hard drives and the first headphone CD players with mp3 functionalities are brought to market. mp3 increasingly becomes a cultural phenomenon, too, with hundreds of millions of mp3 capable computers and consumer electronic devices sold annually.
2006: In Germany, mp3 secures more than 10.000 jobs and the tax revenue for the German state sums up to around 300 Million Euros each year. Germans spend around 1.5 billion Euros on mp3 players and mp3 related products.
The possibility to store thousands of mp3 encoded songs on a small portable player, search them by album, artist, title, genre or even to have play lists generated automatically has reawakened millions of people's love for music. You no longer have to look for a misplaced CD in order to listen to a song you have missed for years. The whole music collection is available at the push of a button. In fact, inexpensive 40GB mp3 players today can store over 10,000 songs of CD quality readily available whenever and wherever you are.
mp3 is more than just a technology. It is a sensational development that connects musicians with music lovers, speakers with their listeners, artists with their audience.

2007

20 Years of Audio Coding at Fraunhofer IIS

In 2007 Fraunhofer IIS celebrates 20 successful years of developing audio coding algorithms. Today, the German institute is the worldwide leading independent research lab in the field of high quality audio compression technologies for the modern media world.
In May 1987, developers at Fraunhofer IIS achieved a first important milestone: They presented a real-time implementation of the “Low Complexity Adaptive Transform Codec”, in short LC-ATC. That way, music could be compressed in real-time for the first time – a huge advantage as before compression of audio signals took hours even using high performance computers. Preliminary work started already in the 70s with the goal of compressing music for transmission over phone lines.
World-renowned formats such as mp3 or MPEG-4 AAC evolved from the early beginnings. Thanks to these developments, Fraunhofer IIS enjoys an excellent reputation as the leading independent research lab in the field of audio coding.
For more information, please see our brochure "20 Years of Audio Coding at Fraunhofer IIS" (PDF, 3.6MB).