Skip to main content
Service phase: Beta

This service is still in development. Give us your feedback or view this page on the current PRONOM service.

Format

FLAC (Free Lossless Audio Codec)

Summary

Name
FLAC (Free Lossless Audio Codec)
Version
1.2.1
Identifiers
  • MIME: audio/flac
  • PUID: fmt/279
Format type
Audio
Description
FLAC stands for Free Lossless Audio Codec, an audio format similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality. The basic structure of a FLAC stream is: •The four byte string "fLaC" •The STREAMINFO metadata block •Zero or more other metadata blocks •One or more audio frames The first four bytes are to identify the FLAC stream. The metadata that follows contains all the information about the stream except for the audio data itself. After the metadata comes the encoded audio data.
File extensions
flac
Source
The National Archives and Records Administration / The National Archives and Records Administration

Internal signatures

FLAC (Free Lossless Audio Codec)

Note
BOF: 'fLaC' with optional byte (80|00) followed by '.."'

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
4
Byte Sequence
664C6143(80|00)000022
Endianness
None

Changelog

  • Updated in V98

    Release date
    27 October 2021

    FLAC: Signature updated with an either or (80|00). Signature developed and samples provided by Landesarchiv Nordrhein-Westfalen.

  • Updated in V92

    Release date
    20 September 2017

    FLAC (Free Lossless Audio Codec) 1.2.1: Added MIME type.

  • Updated in V72

    Release date
    12 November 2013

    FLAC (Free Lossless Audio Codec): Improved internal signature through PRONOM Research.

  • Added in V38

    Release date
    1 August 2010

    FLAC (Free Lossless Audio Codec): Signature developed from FLAC documentation

    FLAC (Free Lossless Audio Codec): Outline entry added