Free Lossless Audio Codec

Infobox file format
name = Free Lossless Audio Codec
icon =

extension = .flac
mime = audio/x-flac [Registration being sought as audio/flac]
type code =
uniform type =
magic =
owner =
genre = Audio
container for =
contained by =
extended from =
extended to =
standard =Infobox Software
name = Free Lossless Audio Codec



caption =
developer = Xiph.Org Foundation
latest_release_version = 1.2.1
latest_release_date = release_date|2007|09|17
latest preview version =
latest preview date =
operating_system = Cross-platform
genre = Audio codec, Audio file format
license = GPL
BSD (Xiph.Org parts)
website = http://flac.sourceforge.net

Free Lossless Audio Codec (FLAC) is a file format for lossless audio data compression. Being lossless, FLAC does not remove information from the audio stream, as lossy compression formats such as MP3, AAC, and Vorbis do. FLAC's primary author is Josh Coalson.

FLAC reduces bandwidth and storage requirements without sacrificing the integrity of the audio source. A digital audio recording (such as a CD track) encoded to FLAC can be decompressed into an identical copy of the audio data. Audio sources encoded to FLAC are typically reduced in size 40 to 50 percent (46% according to their own comparison). [cite web |url=http://flac.sourceforge.net/comparison.html |title=FLAC - comparison |accessdate=2008-01-27]

FLAC is suitable for everyday audio playback and archival, with support for tagging, cover art and fast seeking. FLAC's free and open source royalty-free nature makes it well-supported by many software applications, but FLAC playback support in portable audio devices and dedicated audio systems is limited at this time. [http://flac.sourceforge.net/links.html#hardware FLAC Website] ]

On January 29, 2003, Xiphophorus (now called the Xiph.Org Foundation) announced the incorporation of FLAC under their banner, alongside Vorbis, Theora, Speex, and others.

The project

The FLAC project consists of:
* The stream format
* A simple container format for the stream, also called FLAC (or "Native FLAC")
* libFLAC, a library of reference encoders and decoders, and a metadata interface
* libFLAC++, an object wrapper around libFLAC
* flac, a command-line program based on libFLAC to encode and decode FLAC streams
* metaflac, a command-line metadata editor for .flac files and for applying Replay Gain
* Input plugins for various music players (Winamp, XMMS, foobar2000, musikCube, and many more)
* With Xiph.org incorporation, the Ogg container format, suitable for streaming (also called "Ogg FLAC")

"Free" means that the specification of the stream format can be implemented by anyone without prior permission (Xiph.org reserves the right to set the FLAC specification and certify compliance), and that neither the FLAC format nor any of the implemented encoding/decoding methods are covered by any patent. It also means that the reference implementation is free software. The sources for libFLAC and libFLAC++ are available under Xiph.org's BSD license, and the sources for flac, metaflac, and the plugins are available under the GPL.

In its stated goals, the FLAC project encourages its developers not to implement copy prevention features of any kind. [http://flac.sourceforge.net/developers.html FLAC Website] ]

Comparisons

FLAC is specifically designed for efficient packing of audio data, unlike general lossless algorithms such as ZIP and gzip. While ZIP may compress a CD-quality audio file by 10 - 20%, FLAC achieves compression rates of 30 - 50% for most music, with significantly greater compression for voice recordings.

Lossy codecs can achieve ratios of 80% or more by discarding data from the original stream. FLAC uses linear prediction to convert the audio samples to a series of small, uncorrelated numbers (known as the residual), which are stored efficiently using Golomb-Rice coding. It also uses run-length encoding for blocks of identical samples, such as silent passages. The technical strengths of FLAC compared to other lossless codecs lie in its ability to be streamed and in a fast decode time, which is independent of compression level.

As a lossless scheme, FLAC is also a popular archive format for owners of CDs and other media who wish to preserve their audio collections. If the original media is lost, damaged, or worn out, a FLAC copy of the audio tracks ensures that an exact duplicate of the original data can be recovered at any time. An exact restoration from a lossy archive (e.g., MP3) of the same data is impossible. A CUE file can optionally be created when ripping a CD. If a CD is read and ripped perfectly to FLAC files, the CUE file allows later burning of an audio CD that is identical in audio data to the original CD, including track order, pregaps, and CD-Text. However, additional data present on some audio CDs such as lyrics and CD+G graphics are beyond the scope of a CUE file and most ripping software, so that data will not be archived.

The European Broadcasting Union (EBU) has adopted the FLAC format over its Euroradio network for the distribution of high quality audio.

The Hydrogenaudio Wiki features a [http://wiki.hydrogenaudio.org/index.php?title=Lossless_comparison comparison] of lossless codecs, including FLAC.

Technical details

FLAC supports only fixed-point samples, not floating-point. It can handle any PCM bit resolution from 4 to 32 bits per sample, any sampling rate from 1 Hz to 1,048,570 Hz in 1 Hz increments, and any number of channels from 1 to 8. Channels can be grouped in cases like stereo and 5.1 channel surround to take advantage of interchannel correlations to increase compression. FLAC uses CRC checksums for identifying corrupted frames when used in a streaming protocol, and also has a complete MD5 hash of the "raw PCM" audio stored in its "STREAMINFO" metadata header.

FLAC allows for Rice parameter between 0-16, and up to 8 channels of audio and a wide range of sampling rates up to 192 kHz, in various bits-per-sample width. FLAC also supports Replay Gain.

FLAC is implemented as the libFLAC core encoder & decoder library with the main distributable program "flac" being the reference program utilizing the libFLAC API. This codec API is also available in C++ as libFLAC++.

The reference implementation of FLAC compiles on many platforms, including most Unix (such as Solaris and Mac OS X) and Unix-like (including Linux and BSD), Windows, BeOS, and OS/2 operating systems. There are build systems for autoconf/automake, MSVC, Watcom C, and Xcode.

For tagging, FLAC uses the same system as Vorbis comments. [cite web |url=http://flac.sourceforge.net/faq.html#general__tagging |title=FLAC - faq |accessdate=2008-01-27]

API organization

libFLAC API is organized into streams, seekable streams, and files (listed in the order of increasing abstraction from the base FLAC bitstream). Most FLAC applications will generally restrict themselves to encoding/decoding using libFLAC at the file level interface.

Software support

Encoding

* Cross-Platform
** FFmpeg
** [http://flake-enc.sourceforge.net/ Flake]
** Audacity 1.3.3 Beta Native FLAC support now included
** VLC media player 0.8.6a
** Juce
** aTunes
* Windows
** [http://www.audio-transcoder.com/ Audio Transcoder]
** BonkEnc — ‘rip’ directly from CD to FLAC file, or FLAC in the .ogg/.oga container
** GOM Player
** [http://smplayer.sourceforge.net/ SMPlayer]
** KMPlayer
** Ease Audio Converter
** Easy Media Creator
** Exact Audio Copy
** [http://www.poikosoft.com/ Easy CD-DA Extractor]
** GoldWave
** Nero Burning ROM with optional external filter plug-in
** dBpoweramp Music Converter with official codec
** Media Center since version 12.0.3xx
** [http://www.mediajukebox.com/ Media Jukebox] free version of Media Center (minus picture and video support)
** MediaMonkey
** Winamp native FLAC support now included
** JetAudio
** foobar2000 with official external encoder
** MP3 Stream Editor with official external encoder
** Omni Encoder with official external encoder
** Burrrn
** Flac Frontend
** Total Audio Converter
** Vegas Pro 8 [http://www.sonycreativesoftware.com/products/product.asp?PID=457&PageID=107]
** Sound Forge 9 [http://www.sonycreativesoftware.com/soundforge]
** VUPlayer [http://www.vuplayer.com/vuplayer.php]
** Yahoo! Music Jukebox
** [http://www.roxio.com/ Roxio Easy Media Creator]
** [http://code.google.com/p/reflacer/ Reflacer]
* Mac OS X
** Toast Titanium, beginning with version 7
** xACT, not to be confused with Microsoft's XACT audio programming library
** Max
**MacFLAC

Decoding

*Cross-Platform
** FFmpeg
** aTunes
**Audacity 1.3.5 Beta
** JUCE (cross-platform C++ toolkit that has embedded FLAC support)
** [http://www.linn.co.uk/digital_stream_players Linn Digital Stream Players] (see below for range of devices)
** MPlayer
** Songbird
** Squeezebox
** The Core Pocket Media Player with flac plugin
** VLC media player
* Mac OS X
** Ableton Live
** [http://people.xiph.org/~arek/flac_import/ FLAC Importer] , Quicktime Component
** Cog
** Play
** Fluke
** xACT, not to be confused with Microsoft's XACT
** TRAKTOR 3
** TRAKTOR Scratch
* Audio programming libraries:
**MacFLAC, decodes to file, no player functionality
** FLACer
* Windows
** Ableton Live
** AIMP
** ALTools-based ALSong
** [http://www.audio-transcoder.com/ Audio Transcoder]
** Billy (music player) since version 1.04i
** Ease Audio Converter
** [http://www.poikosoft.com/ Easy CD-DA Extractor]
** foobar2000
** GoldWave
** Media Center since version 12.0.3xx
** [http://www.mediajukebox.com/ Media Jukebox] free version of Media Center (minus picture and video support)
** iTunes after installing codec from Xiph (Ogg FLAC only)
** [http://www.cirlinca.com Cirlinca DVD-AUDIO Solo] can import FLAC to burn DVD-Audio discs
** JetAudio
** KSP Sound Player plugin included with normal install
** MediaMonkey
** MP3 Stream Editor plugin included with normal install
** Cockos REAPER Multitrack Recorder and Editor
** Renoise supports import and export from version 1.8
** Quintessential Player with flac plugin
** The KMPlayer
** TRAKTOR 3
** TRAKTOR Scratch
** TVersity, using ffdshow to transcode stream to WAV
** Vegas Pro 8 [http://www.sonycreativesoftware.com/products/product.asp?PID=457&PageID=107]
** VUPlayer [http://www.vuplayer.com/vuplayer.php]
** Winamp
** Windows Media Player and Media Player Classic with third-party plugin
** FairStars Audio Converter
** Yahoo! Music Jukebox
*Windows Mobile
** Kinoma Play
* Linux
** Audacious
** Banshee
** Baudline
** cmus
** mpd
** ogg123 (if compiled against flac - ogg123 is part of the 'vorbis-tools' package)
** Xine
** XMMS
** GNOME
*** GnomeBaker
*** Quod Libet
*** Rhythmbox
*** Totem Movie Player
*** Serpentine
** KDE
*** Amarok
*** JuK
*** [http://www.kde-apps.org/content/show.php?content=12608/ Audiokonverter] (from the context menu pop-up)

Ripping

*Cross-Platform
** aTunes
* Windows
** [http://www.audio-transcoder.com/ Audio Transcoder]
** BonkEnc using the FLAC.dll API
** CD to MP3 Maker
** CDex using the external encoder option (now lists "flac.dll" as an encoder option if flac is installed)
** DBpoweramp
** [http://www.poikosoft.com/ Easy CD-DA Extractor]
** Exact Audio Copy using the external encoder
** foobar2000 using the Converter plugin and the external encoder
** MediaMonkey
** MP3 Stream Editor using the official external encoder (single mode/album mode/full cover picture support)
** JetAudio
** Winamp
** PlexTools
** Yahoo! Music Jukebox
* Mac OS X
** Max (Mac OS 10.4 or higher)
* Linux
** ABCDE
** Asunder
** Banshee (music player)
** Cdda2wav
** Cdparanoia
** Mencoder
** crip
** [http://www.suwald.com/ripit/ripit.html RipIt] (Command line tool)
** GNOME
*** Grip
*** RipOff
*** Sound Juicer
** KDE
*** K3b
*** KAudioCreator
*** Konqueror

Hardware support

Native

* Escient [cite web |url=http://www.escient.com/support/supportdocuments/DigitalMusicFilesFormats.pdf |title=Supported Digital Music Formats & Tagging Requirements |accessdate=2008-01-27 |format=PDF |publisher=Escient |pages=p. 2]
* iAudio (Cowon) - A2, A3, 6, 7, F2, M3, M5, X5, U3, U5 [ [http://download.cowon.com/data/C08/U5/v2_13/U5_2.13.zip Korean firmware V2.13] ] , D2, native support with newer firmwares.
* Olive (Symphony, Musica, Opus) [cite web |url=http://www.olive.us/products/preloadterms.html?PHPSESSID=23dfebfa0 |title=Olive | Save The Sound. - Olive'S Free Cd Ripping Service - Preload Terms |accessdate=2008-01-27]
* PhatBox Hard Drive based in car Digital Media Player from PhatNoise
* Rio Karma
* SanDisk Sansa Fuze, Clip
* Squeezebox and Transporter network music players from Slim Devices. Current products decode natively. Old v1 units transcode to PCM on the server.
* Sonos
* Meizu M6 Mini Player, M3 Music Card
* Pixel Magic Systems' HD Mediabox (with firmware 1.3.4 or higher)
* Embedded Waveplayer- Module with FLAC level 0-2 support, MIDI and serial interface
* Teclast T29, T39, C260, C280, C290
* Trekstor Vibez
* Denon AVR-4308 & AVR-3808 AV Receiver [cite web |url=http://www.denon.co.uk/site/frames_main.php?main=prod&ver=&MID=3&sub=1&action=detail&Pid=340 |title=DENON UK | Home Audio Components |accessdate=2008-01-27 |format= |work=]
* T+A Music Player [cite web |url=http://www.taelektroakustik.de/eng/ta2/e_system/music_player.htm |title=T+A E-Series Music-Player |accessdate=2008-01-27]
* Linn Klimax DS (Digital Stream) - Digital Music Player
* Linn Akurate DS - Digital Music Player
* Linn Majik DS - Digital Music Player
* Linn Sneaky Music DS - Digital Music Player
* iriver E100 [cite web |url=http://www.iriver.com.au/iriver/index.cfm?pageID=2&sID=1&prodID=23&# |title=iRiver E100]
* NMT players

Third-party

* Microsoft Xbox when running the third party Xbox Media Center
* iPod - 1st through 5.5th generation, iPod mini and 1st generation iPod nano (not the shuffle, 2nd/3rd gen nano, classic or touch), using third party Rockbox firmware
* Nearly all Rockbox-compatible DAPs, including the iriver and Gigabeat (Toshiba) range of devices, plus the aforementioned iPods
* Any UPnP A/V / DLNA Device - - e.g. Netgear EVA700, Netgear MP101, Roku Soundbridge or Xbox 360 (when transcoded data is streamed from applications such as TVersity, which uses ffdshow)
* Sound Devices 7-Series Professional Audio Recorders with "badger" firmware update (v.2.24) [cite web |url=http://www.sounddevices.com/notes/recorders/file-formats/compression-reduction/ |title=Data Compression and Reduction Options for 7-Series Recorders | Sound Notes | Sound Devices, LLC |accessdate=2008-01-27]
* Sony PlayStation Portable when running LightMP3. [http://dl.qj.net/LightMP3-v1.7.1-(FLAC-bugfix)-PSP-Homebrew-Applications/pg/12/fid/15529/catid/151]

See also

* Comparison of audio codecs
* Meridian Lossless Packing
* Monkey's Audio
* TTA
* WavPack

References

External links

* [http://flac.sourceforge.net/ Official Website]
* [http://web.inter.nl.net/users/hvdh/lossless/lossless.htm Comparison of lossless formats] by Hans Heiden (somewhat outdated)