flac: flac (Free Lossless Audio Codec) flac: flac: FLAC stands for Free Lossless Audio Codec. Grossly oversimplified, flac: FLAC is similar to MP3, but lossless. "Free" means that the flac: specification of the stream format is in the public domain, and that flac: neither the FLAC format nor any of the implemented encoding/decoding flac: methods are covered by any patent. It also means that the sources for flac: libFLAC and libFLAC++ are available under the LGPL and the sources for flac: flac, metaflac, and the plugins are available under the GPL. flac: flac: FLAC was developed by Josh Coalson.