30 years MP3: When music came online

This article first appeared on Heise Online in 2020. We publish it again in a slightly updated form for the 30th anniversary of MP3.

That with the anniversaries in technology is tricky – because there are usually several appointments that come into question as a birthday. It is also the case with MP3: For audio files that have been caught up according to their procedure, the project participants at the leading Fraunhofer Institute for Integrated Circuits (IIS) determined on July 14, 1995 according to internal vote “.MP3”. In the house, the files were called “.bit” up to this point. But the sophisticated system and even scolded as an over-complex system was already fixed on the MPEG meeting from November 2 to 6, 1992 in London. The history of development goes back to the 1970s – the “pregnancy” lasted more than a decade.

MP3 is the short form of MPEG 1/Layer III – the abbreviation MPEG (emphasized) stands for “Moving Picture Experts Group”. MPEG dealt with the data reduction of images process and therefore had to come up with something for the sound. Goal: The comparatively high data rate of PCM (Pulse code modulation) digitized audio signals evaporate on quantities that enable digital radio or use on data carriers that have less capacity than the CD.

This was researched in many places in the world-Sony worked for his Minidisc on Atrac, Dolby to AC-1, the forerunner of the AC-3, which was later marketed as a Dolby digitally marketed. In Germany and the Netherlands alone there were three camps: the first group was built around Philips and the Munich Institute for Broadcasting Technology (IRT) and worked on a system called “Musicam”. Initially, Karlheinz Brandenburg was traveling as a lone fighter, who researched possibilities at the University of Erlangen, subjectively to talent the data flood of digital sound signals. “We wanted to save the signal in such a way that it contains everything that is passed on from the inner ear to the nerve pathways,” says Brandenburg in an interview with Heise Online. Team three formed with Detlef Krahé at the University of Duisburg and Ernst F. Schröder von Thomson (then Telefunken, today Technicolor). Ultimately, there were team 2 and 3 whose work culminated in MP3.

Patent refuses – “that can’t work!”

Brandenburg acted on behalf of: his doctoral supervisor, Professor Dieter Seitzer, later founder of Fraunhofer IIS, had the idea of spreading music about ISDN telephone network in Hi-Fi quality in the 1970s. He wanted to have the first ideas protected – the patent was initially not granted because the examiners believed that according to the state of the art, no music could be transferred with the target bit rates. Seitzer found the doctoral student in Karlheinz Brandenburg, who took on the topic. Brandenburg soon moved to the straight founded IIS, where a group under the direction of Professor Heinz Gerhäuser continued to research.

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Initially, all researchers braked the available computing power – it may take hours before coding a sound example with the required parameters. In Europe, the technology recorded with the allocation of the EU project 147 (“Eureka”), which was to help the digital radio in the EU breakthrough. At the same time, the first real -time systems were available, which accelerated research significantly. MPEG was founded in 1988, after various hearing tests, MPEG 1/Layer I first used as a slimmed-down musicam variant on the long-forgotten digital compact cassette (DCC).

Long dry spell

MPEG 1/Layer II is the somewhat more complex musicam variant. It is the standard for SD digital TV and radio via cable and satellite and is used for terrestrial digital radio DAB (Digital Audio Broadcast). In Germany, however, the first DAB could not prevail. This did not work until 2011 with DAB+, whose codec is based on AAC (Advanced Audio Coding). MPEG 1/Layer III-MP3-is based on the Thomson/Fraunhofer development Aspec (Adaptive Spectral Perceptual Entropy Coding) and the modified discrete cosineustran formation (MDCT). The latter is one of the MP3 key technologies-it came into the system after the University of Hannover with Hans-Georg Musmann and Bernd Edler joined the project in 1988.

While Layer II was running on the radio, the teams around Thomson and Fraunhofer only had a look. But patience paid off. Thomson-Mann Schröder said Heise Online: “Brandenburg had long sight and perseverance.” He searched for applications away from the classic radio and relied on the rapidly growing computing power of PC processors.