libFLAC

libFLAC is a portable, open-source library that implements the Free Lossless Audio Codec (FLAC). It provides a C API for encoding and decoding FLAC streams and is part of the FLAC project.

The library exposes streaming and encoding/decoding interfaces. It supports encoding from PCM data and decoding to PCM, with options for compression level (0–8), sample rate, bit depth, and channel count (up to 8). It handles FLAC metadata blocks, including STREAMINFO, SEEKTABLE, VORBIS_COMMENT, and PICTURE blocks. LibFLAC can be used in both encoding and decoding pipelines; there is also a C++ wrapper library libFLAC++.

Usage typically involves creating an encoder or decoder object, configuring parameters, feeding or retrieving PCM data, and finalizing the stream. It runs on major platforms, including Windows, macOS, and Linux, and supports both in-memory buffers and I/O callbacks for data transfer.

Licensing and availability: libFLAC is released under a permissive BSD-like license. Source code and binaries are available from the FLAC project and through major distribution repositories. The library is widely supported by multimedia applications and toolchains.

Impact and ecosystem: libFLAC is widely adopted in audio players, editors, and transcoding tools as the reference implementation for FLAC encoding and decoding. It remains actively maintained alongside ongoing developments in the FLAC format and ecosystem.