FLAC (Free Lossless Audio Codec) is an open-source lossless audio compression format. FLAC files are mathematically identical to the original audio — decompressing a FLAC produces a bit-for-bit copy of the source. Unlike MP3 or AAC, no audio data is removed. Despite being lossless, FLAC achieves file size reductions of 40-60% compared to uncompressed WAV, making it excellent for archiving music collections.
FLAC works by predicting audio sample values using previous samples (linear predictive coding) and storing only the residual errors, which are then entropy-coded. Music with regular patterns (piano, guitar chords) compresses better than highly random signal content (white noise). Encoding and decoding FLAC is fast, requiring much less CPU than lossless video codecs.
Device support: Android natively supports FLAC. Windows 10+ supports FLAC. Mac and iOS support FLAC through compatible apps (not natively in Music app — Apple uses ALAC). VLC plays FLAC universally. FLAC is the audiophile's choice for digital music libraries. For mobile playback and sharing, convert to AAC or MP3 to reduce file size while maintaining excellent quality.