What is FLAC?
FLAC is a lossless audio codec designed to reduce file size without changing the decoded PCM audio.
FLAC technical specifications
| Property | FLAC format limit |
|---|---|
| Channels | 1–8 |
| Bits per sample | 4–32 bits |
| Maximum sample rate | 1,048,575 Hz (220 − 1) |
| Compression | Lossless |
| Bitrate | No single fixed range; depends on source PCM, content and compression efficiency |
The formal limits are much wider than normal music-library values. Hardware and software support is often narrower than the FLAC bitstream itself.
Common FLAC values
Most music files are 16-bit or 24-bit and use familiar rates such as 44.1, 48, 88.2, 96, 176.4 or 192 kHz. High-end hardware may support 352.8 or 384 kHz FLAC, but that is still only a subset of what the format can represent.
Why FLAC has no fixed bitrate
FLAC stores PCM losslessly, so the encoded bitrate changes with sample rate, bit depth, channel count and how compressible the audio is. Two 24-bit/96 kHz stereo tracks can therefore have different FLAC bitrates while decoding to PCM with the same basic technical resolution.
FLAC codec vs FLAC file
A normal .flac file contains a native FLAC stream plus metadata. FLAC audio can also be carried by other containers, including Ogg, Matroska and MP4 in implementations that support it.