LameXP - LameXP is an Audio Encoder Front-End, a graphical user-interface for a number of audio encoders.
FLAC - A free, open source codec for lossless audio compression and decompression
SoundConverter - The sound conversion application for the GNOME environment.
Opus Interactive Audio Codec - Opus is a totally open, royalty-free, highly versatile audio codec.
fre:ac - fre:ac is a audio converter and CD extractor designed for Microsoft Windows, Mac OS and Linux, distributed under the GNU General Public License.
Vorbis - Ogg Vorbis is a fully open, general-purpose compressed audio format for mid to high quality...