Free Lossless Audio Codec

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What is FLAC?

Grossly oversimplified, FLAC is similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality. This is similar to how Zip works, except with FLAC you will get much better compression because it is designed specifically for audio, and you can play back compressed FLAC files in your favorite player (or your car or home stereo, see supported devices) just like you would an MP3 file.

FLAC stands for Free Lossless Audio Codec. "Free" means "Free" - that the specification of the stream format is in the public domain. It also means that the sources for libFLAC and libFLAC++ are available under the BSD (Berkeley Software Distribution)

FLAC compiles on many platforms.

Some claim FLAC is the most widely used lossless compression format on UNIX systems (though it seems more likely that shn retains that honor on all OS platforms).


  • Portable to many systems
  • Source open and freely licenced
  • Hardware support (PhatBox, Kenwood MusicKeg, Rio Karma, etc. See below)
  • Streaming support
  • Extremely fast decoding
  • Supports multichannel and high resolution streams
  • Supports ReplayGain
  • Supports cue-sheet (with some limitations)
  • Gaining wide use as successor to Shorten


  • Compresses less efficiently than other popular modern compressors (Monkey's Audio, OptimFROG)
  • Higher compression modes slow, for little gain over the default setting.

Players that support FLAC

For a more complete list see the FLAC links page.


Home stereo

Car stereo




Frontends (Windows)

Frontends (Mac)



  • CoolEdit

CD writers/rippers


Other tools

...and many more; see the FLAC software section and download section for a more comprehensive list.

Frequently Asked Questions

Question: Does the compression level affect decompression speed?

Short Answer: No.

Long Answer: In truth, the compression level does affect the decompression speed, but the difference between the various compress levels can barely be measured and is too small to be noticed, even on low-end machines.

Question: What is the best compression level for encoding my music?

Short Answer: The default setting, 5.

Long Answer: Encoding at the default setting will give the best balance between compression and encoding speed. Encoding at 8 can more than quadruple the encoding time, while having an insignificant effect on compression.

See also: FLAC FAQ

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