Fraunhofer l3enc was the first public software able to encode PCM (.wav) files to the MP3 format. The first public version was released on July 13, 1994.[1] This commandline tool was shareware and limited to 112 kbit/s. It was available for MS-DOS, Linux, Solaris, SunOS, NeXTstep and IRIX.[2] A licence that allowed full use (encoding up to 320 kbit/s) cost 350 Deutsche Mark, or about 250 US$.

Since the release (9 September 1995) of Fraunhofer WinPlay3, the first real-time MP3 software player, people were able to store and play back MP3 files on PCs. For full playback quality (stereo) one would have needed to meet the minimum requirements of a 486DX2/66 processor.

By the end of 1997 l3enc stopped being developed in favour of the development of MP3enc, which is the successor to l3enc.[2] It was often referred to as the “gold standard of encoders”.[3] It was available for Windows, Linux, Solaris, SunOS, IRIX and Alpha.[4] Development of MP3enc stopped in late 1998 to favour development of a parallel branch FhG had been developing for some time, called Fastenc.[5] None of these programs are still marketed.

An mp3 Surround encoder and mp3HD codec and Software Tools are now promoted on the Fraunhofer MP3 website.[6]

MP3 source code leak

It is speculated that a hacker named SoloH got access to the source code of the "dist10" MPEG reference implementation shortly after the release from the servers of the University of Erlangen. He developed a higher quality version and spread it on the internet. This leak started the widespread CD ripping and digital music distribution as MP3 over the internet.[7][8][9][10]

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Deutsch: L3enc