FLAC (Free Lossless Audio Codec) is a free open source lossless audio encoding format designed by the Xiph.Org Foundation and first release on 2001-07-20. The compression algorithm is designed with audio data in mind, so it typically compresses to around 60% of the original size, better than generic lossless compression like ZIP or 7Z. FLAC also has native support for meta data tags, replay gain, and album art. Although the format was by no means the first lossless audio codec available, the fact that it was both open source and parent-free helped it to gain popularity faster than its predecessors. FLAC is now supported by every major operating system, web browser, and mature audio player.
Below is a comparison of an uncompressed three minute long pop song to general purpose compression algorithms and various levels of FLAC compression.
|WAV||31,935,500||Uncompressed audio data.|
|ZIP||29,485,937||The DEFLATE algorithm using 7-Zip's "ultra" compression.|
|7Z||23,050,798||The 7Z format using 7-Zip's "ultra" compression.|
|FLAC||20,878,568||Using "0" level compression. Emphasizes speed over compression.|
|FLAC||19,305,501||Using "8" level compression. Emphasizes compression over speed.|
|FLAC||19,190,099||Optimized with FLACOut.|
I found out about FLAC around the same time I found out about Vorbis in the mid-2000s. In my process of ripping my CD library to my computer's hard drive, I wanted to find the best audio format use. I initially used Vorbis, but, not liking the idea of permanently losing quality, I switched to FLAC soon after. I have since been an advocate for FLAC and, though I still use a lossy audio format on my mobile devices, all of my audio is always backed up in FLAC format.