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What is FLAC - Free Lossless Audio Codec

FLAC stands for Free Lossless Audio Codec, which is an audio coding format for lossless compression of digital audio. The "free" in FLAC means both royalty-free licensing and a reference implementation which is free software. Unlike other formats such as MP3, AAC, the most extinct feature of FLAC is that it remains original audio quality thus was widely supported by various software and devices. FLAC is capable of compressing digital audios into 1/2 of its original size and also decompressing target files to an identical copy of the original version.


FLAC was started by Josh Coalson in 2000. The bit stream format was frozen when FLAC began being tested on the version 0.5. On 15 January 2001, Josh Coalson released the version 0.5 as a reference implementation. Later on, the version 1.0 was released on 20 July 2001.

On 20 January 2003, Xiphophorus announced that FLAC along with Ogg Vorbis, Ogg Theora, and Speex became open source projects under the Xiphophorus banner.

On 26 May 2013, the version 1.3.0 was released and moved its point development to Xiph.org Git repository.


The FLAC project includes: The stream format, ibFLAC, ibFLAC++, flac, metaflac, input plugins and Ogg FLAC.

The open format FLAC can be used without requiring prior authorization because it maintains copyright to redefine its standard and compatibility. It can be proved when FLAC encodes without any protected patent. The source code for libFLAC and libFLAC++ is released under BSD license while the source of flac, metaflac and other plugins are launched under the General Public License.

Any kind of copy prevention feature is not encouraged to be implemented by its developers for stated goals of FLAC.

Main features

1. Lossless compression. The audio data would be lossless when being encoded (see how to convert lossless FLAC using FLAC converter), which makes audio with FLAC format remaining its original sounds.

2. Fast speed in decoding.

3. Hardware supported. FLAC is the only widely hardware supported lossless audio codec since 2012.

4. Available in stream media.

5. Positioning supported.

6. Suitable for archives applications. Since FLAC is an open and lossless audio codec, it can be converted into any required format. When it encodes, FLAC will compare with the original data and send notice if the data were different when checking.

7. Flexible metadata. It can be defined and improved with no effect on the use of data stream and encoder.

8. Convenience for copying data from DVD. There is a cue form on the FLAC, which stores all the contents and soundtracks in a single file. Whenever your CD damaged, another duplicated audio can be copied from the backup file.

9. Anti-damage: Thanks to its frame structure, the loss could be controlled within damaged frames when the data stream was corrupted.

Visit our: How to Convert FLAC to Apple Losselss ALAC on a Mac


Monkey's Audio is an algorithm and file format for lossless audio data compression. Unlike lossy compression methods such as AAC, MP3, Vorbis and Musepack, lossless data compression does not discard data during the process of encoding. The file of Monkey's Audio sounds exactly the same as the original one. APE owns its position and becomes a popular format before FLAC shows up.

FLAC has support for metadata tagging, album cover art, and fast seeking.

1. Compression ratio

Among all the lossless codecs, the compression rate of APE is the best and even better ever than that of FLAC. If it was under the same speed of compression, the compression ratio FLAC and APE is almost no difference.

2. Supported platform

Compared with APE, FLAC has lower demand on encode standard and is the only widely available codec that supported by hardware. In the current multimedia market, FLAC is accepted by multimedia player, vehicles and stereos while APE is officially supported by Windows. In hardware aspect, FLAC is more supported than APE.

3. Error tolerance

APE has bad error tolerance which means that the audio of APE format could be null if there was any error or data lost during transmitting process. However, FLAC can totally avoid this trouble for each frame of it is separated.