FLAC stands for Free Lossless Audio Codec, an audio format similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality. FLAC may never actually supplant MP3, but if you care about sound quality, then FLAC is undoubtedly your best option. Flac bit rate may range from 800kbps to 1500kbps whereas mp3 files are available in 128kbps, 190kbps and 320kbps.