Free Lossless Audio Codec

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) licence.

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).

FLAC files can be placed inside an Ogg container using libOggFLAC and libOggFLAC++.

Pros

• 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

Cons

• 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.

Hardware

Home stereo

• AudioReQuest music servers
• Digital Techniques' "iStereo" M300A Digital Music Player
• Escient's FireBall servers (E2-40/160/300, DVDM-300)
• Hifidelio
• Meda Systems' Bravo servers
• The MS300 Music Server by McIntosh Laboratory
• Olive's Symphony wireless digital music center
• PhatNoise Home Digital Media Player
• Rio Reciever and Dell Digital Audio Receiver
• Roku PhotoBridge HD (with plugin)
• SkipJam's networked audio/video devices
• Sonos Digital Music System
• Squeezebox2 and Squeezebox 3 (earlier models support via Slimserver)
• Zensonic Z500 Networked DVD Media Player

Car stereo

• Kenwood Music Keg
• PhatBox

Portable

• Apple iPod with Rockbox firmware
• iAudio M3 and X5
• iRiver iHP-120/iHP-140 with Rockbox firmware
• Iwod G10
• Rio Karma

Software

Players

• Apollo
• foobar2000
• JRiver Media Center
• LAMIP
• MPlayer
• MythTV
• QCD (plugin)
• VLC
• VUPlayer
• Winamp
• Windows Media Player and other directshow-based players (MPC, TCMP, RadLight) (with Illiminable's directshow filters or CoreFLAC)
• Xine
• XMMS
• XMplay

Frontends (Windows)

• Flacattack
• Custom Windows Frontend (by Speek)
• UniversalFront by Böreck
• Frontah by Madah
• Mareo by Kwambis

Frontends (Mac)

• MacFLAC
• RipBeak
• xACT

Converters

• dBpowerAMP Music Converter / Audio Player / CD Writer
• GX:Transcoder Music converter

Editors

• Adobe Audition

CD writers/rippers

• Ahead Nero Burning Rom
• Arson
• burnatonce
• Burrrn Audio CD burner
• Exact Audio Copy CD Ripper
• CDex CD ripper
• CD Wave

Taggers

• Mp3tag Universal Tag Editor
• The GodFather Tagger / Music manager
• Case's Tag command line tagger

Other tools

• Mr. QuestionMan
• Audio Identifier
• mkvtoolnix - tool to multiplex FLAC streams inside the Matroska container

...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

Addtional Reading

• FLAC Project Webpage
• Download
• Rio Karma
• Speek's Comparison of lossless audio compressors
• Lossless Codec Comparison by Rjamorim
• Omion's FLAC "File Size vs. Decoding Speed" test - a very thorough test on the influence of the chosen encoding level on the decoding speed of FLAC; the only one so far to have covered FLAC's --super-secret-totally-impractical-compression-level to this extent as well.