Fraunhofer MP3 Encoders
Fraunhofer-Gesellschaft (FhG) is a German company that helped pioneer MP3 technology. The institute is a center of ongoing research of audio coding at low bitrates. Basically they are trying to achieve the best sound quality out of the lowest file size. Since 1998, Fraunhofer has put out a series of encoders that have matched their technological advances.
FastEnc - Fraunhofer's new fast encoder that they say encodes at 10X real time on a PIII 500 machine (a 4 minute song would only take 24 seconds to encode). It supports a full range of bitrates from 8-320 kbps, VBR, and can be found in Virtuosa Gold Phoenix Edition and Music Match Jukebox 6.0.
MP3Enc - High quality command line encoder with an available demo for download. If you buy the software from Opticom, you will also get the L3dec decoder. Fraunhofer provides a complete online manual for the program including switch commands, basics, advanced features, and bug fixes.
L3Enc - Older version of the MP3Enc codec and is not distributed any more. Good quality but very slow.
FhG Radium - Windows internal codec based on Fraunhofer's original code but not made by Fraunhofer. It is a cracked codec "optimized for various functions" and not endorsed by Fraunhofer.