Erlangen (dpa) - "1000 songs in your pocket." At the premiere of the first iPod in October 2001, Apple CEO Steve Jobs got to the heart of the revolutionary concept of the MP3 music file format.

The MP3 method for data reduction made it possible to actually store 1000 pieces of music on a small hard disk. However, MP3 was not invented in California - rather in large parts in the Franconian town of Erlangen. 25 years ago - on July 14, 1995 - researchers at the Fraunhofer Institute for Integrated Circuits agreed to use the file extension ".mp3" for the file standard they had developed.

The origins of the MP3 project go back to 1982. Back then it was a matter of making music files so small that they could be transferred in good quality over a digital telephone line (ISDN). The student Karlheinz Brandenburg made the apparently unsolvable task the subject of his doctoral thesis at the Chair for Technical Electronics in Erlangen.

But soon it was no longer just about enabling music transmission via ISDN telephony. A small team in Erlangen set out to define the next generation of audio for radio and television. The research was funded primarily from the EU project “Eureka”.

"We were absolute newcomers, we had never built a device in this area," recalls Brandenburg's colleague Bernhard Grill. «We also had no experience in broadcast technology. We started from scratch - on the green field. »

Initially, the researchers from Erlangen had to fight massive reservations, which were scattered in particular by economic competitors. "We were just researchers, and the competition took advantage of this to give us a certain reputation - according to the motto that we would only think of things that are so difficult to implement in practice anyway and that no one will do sensibly," he says Grill.

Because the Moving Picture Experts Group (MPEG) was unable to agree on one method, three different methods were standardized on how music and audio should be stored, transmitted on the Internet and via digital radio in the future. MPEG Layer 1 no longer plays a role. Layer 2 is still used for older television sets with stereo sound. Layer 3, on the other hand, has prevailed on a broad front, which is generally known as MP3 with the name of the file extension 25 years ago. "We had to survive on our technology," says Brandenburg.

However, the MP3 inventor then found that his algorithm failed and sounded terrible on one of his favorite songs, "Tom's Diner" by Suzanne Vega. So he got down to work optimizing the compression process countless times until the a cappella song came across as MP3, of course. «I have probably heard this song thousands of times this way. But because I like the music, it never hung out of my neck. »

The development work of Brandenburg and his colleagues Heinz Gerhäuser, Ernst Eberlein, Bernhard Grill, Jürgen Herre and Harald Popp should not only fundamentally renew the broadcasting technology, but also completely change the music industry.

A criminal hack has also contributed to this MP3 revolution. The Erlangen-based researchers had put a “reference encoder” on the net to demonstrate the skills of MP3. He only encoded music for a minute. However, one student broke the time limit, put this cracked version of the program on the web - and thus triggered the MP3 wave, which peaked on the Napster platform.

The format with the file extension ".mp3" shook the foundation of the music industry, because in one fell swoop it was possible to exchange music worldwide via the Internet, even if the data lines were much slower than today's gigabit connections. Only with the success of the iTunes Music Store in 2003 and legal streaming services like Spotify in 2008 did the music industry slowly recover.

Despite the constant improvements to the codec, i.e. compression process, criticism of MP3 and its successor formats does not stop. An MP3 file is only a weak representation of what analog music could once be; A modest replacement for the miracle that once happened when listening to records, Canadian musician Neil Young said in a TV interview: «Analog music is like a reflection; like a lake in which the landscape is reflected in calm weather. »

MP3 co-inventor Brandenburg can understand the criticism of the original MP3 halfway. However, the new codes such as AAC have become so good at higher data rates that the human ear cannot distinguish them from analog sound transmissions, for example from vinyl records. This has been proven by numerous blind tests - including a study by the British University of Huddersfield. "It is really the expectation that is heard."

In the meantime, Fraunhofer IIS licenses the fourth generation of audio codecs "Made in Germany". "If you buy a cell phone today, it is likely that we have implemented other technologies besides MP3," says Grill, director of the institute: almost all streaming services use the second and third generation of the AAC audio codec. "Our fourth generation is new to smartphones." These enhanced voice services (EVS) for better sound quality in mobile communications (4G and 5G) are not about music this time, but about speech, which is technically the greater challenge than music.

MP3 co-inventor Karlheinz Brandenburg, who made it into the “Internet Hall of Fame” in 2014, no longer accompanies the search for the perfect sound at the Fraunhofer Institute. After almost 20 years there, he retired this June. But he remains active: With his own company, the “Brandenburg Labs”, he is working together with Fraunhofer on a new technology called “Personalized Auditory Reality” or “PARty” for short, which should enable listening, listening or listening. Headphones should help with hearing, like glasses with vision.

The “PARty” headphones should be intelligent, that is, they should perceive the room and automatically analyze all the sound sources. «And then I can say that I want to talk to a certain person, which is hardly possible now because of the strong background noise. Or I want to talk to someone on the phone. But it shouldn't be like now that someone is croaking in my ear, but that I really have the impression that the person is standing a meter next to me and I am talking to them as normal. »

© dpa-infocom, dpa: 200713-99-771865 / 2

Karlheinz Brandenburg in the "Internal Hall of Fame"

MP3 inventors Karlheinz Brandenburg and Berhard Grill in an interview with the Gesellschaft für Informatik

University of Huddersfield study

Neil Young's MP3 review on ARTE TV