What Is FLAC? Free Lossless Audio Codec Explained

Unlike lossy codecs, FLAC discards nothing. It uses linear prediction to model the audio signal, then stores only the small differences between the prediction and the real waveform, encoded efficiently with Rice coding. Decoding reverses the process exactly- Like unzipping an archive. Typical savings are 40-60% versus uncompressed WAV, so a 40 MB track becomes roughly 16-24 MB with no quality change whatsoever. Because every frame is independently decodable, FLAC also handles streaming and seeking gracefully- Jumping to the middle of a long file is instant.

FLAC supports bit depths up to 32-bit and sample rates well beyond studio norms (24-bit / 192 kHz files are common in hi-res stores). It has excellent metadata support- Vorbis comments for tags plus embedded cover art- And each frame carries a checksum, so file corruption is detectable. Compression levels 0-8 trade encoding speed for file size; decoding speed is fast at every level, which matters for portable players.

FLAC is the natural choice for archiving CD rips and master recordings, for critical listening on good equipment, and as a source format you may re-encode later. Because it is lossless, you can convert FLAC to MP3, AAC, or anything else at any time without compounding quality loss- Something repeated lossy-to-lossy conversion cannot offer. See MP3 vs FLAC for a full comparison. FLAC is also the standard delivery format for hi-res download stores and live-recording communities, and storage is now cheap enough that keeping a FLAC master alongside MP3 copies for phones is a very practical library strategy.

FLAC playback is built into Android, Windows 10 and later, and most dedicated audio players. Apple devices historically favoured ALAC instead; modern iOS can play FLAC through the Files app and third-party players, but iTunes/Apple Music still does not import it directly. Car stereos and older MP3 players frequently lack FLAC support too, although network streamers, AV receivers, and most dedicated hi-fi ecosystems handle it well.

For phones, car audio, and easy sharing, the FLAC to MP3 converter produces compact files- Choose 320 kbps to keep quality as high as MP3 allows. Apple users can convert to ALAC instead via MP3 to ALAC style workflows, and MP3 to FLAC exists for tools that only accept FLAC input (it will not recover detail the MP3 already discarded). Either direction takes only seconds for a typical track.