FLAC became the lossless standard by being free: format, patents and implementation.

Lossless audio had a problem: the popular lossy formats, led by MP3, cut data the ear would not notice, but archivists and audiophiles needed every bit. The lossless options were either proprietary or carried licensing complications.

In 2001 Josh Coalson released FLAC, a lossless codec whose defining feature was not just compression but ownership. Xiph.Org later stewarded it, with co-developers including Erik de Castro Lopo, and published it as a clearly documented open format.

The claim that set it apart: it is the only lossless codec that is simultaneously non-proprietary, free of patent burdens and distributed with an open-source reference implementation. Anyone can encode or decode it, and the format and API are well documented.

That combination made it the safe place to put music you must keep, and in December 2024 the format became an internet standard in its own right when RFC 9639 was published.

Make the whole codec free: format, patent and implementation

Lossless compression with no quality loss is exactly what archiving and hi-fi need

Being patent-unencumbered removed legal risk for hardware and software makers

An open-source reference implementation let everyone build on the same base

A documented format and API made independent implementations and long-term access possible

To win a niche where trust and long-term access matter, give away everything needed to implement the format: removing patents opens adoption and lets the codec become the default archive.

FLAC became the standard lossless format in music servers, hi-fi playback, archiving and digital distribution of hi-res audio. The move from a community format to RFC 9639 in 2024 cemented its status. The RISC-V and open-IP worlds still debate whether openness alone is enough to unseat a dominant proprietary format, but in lossless audio FLAC's open model won.