LAME 
Originally an acronym for LAME ain't an MP3 encoder, LAME has evolved into a high-quality, high-speed, and free MP3 encoding engine. Open-source developers began LAME as an educational project to improve psychoacoustics, noise shaping, and encoding efficiency. Today, the engine (found in many forms, from uncompiled source code to software applications) has a reputation of delivering the best-sounding MP3s.