ALAC

ALAC, or Apple Lossless Audio Codec, is a lossless audio data compression format developed by Apple Inc. It reduces the size of digital music files without losing any original audio information, allowing bit-for-bit identical reconstruction of the source when decoded. ALAC files are commonly stored in the M4A or MP4 container formats and are designed to integrate seamlessly with Apple’s ecosystem.

Technical characteristics of ALAC include support for common high-fidelity audio specifications, such as 16- or 24-bit depth and sampling rates up to 192 kHz. The codec uses lossless compression, meaning that the encoded data can be fully restored without any degradation. ALAC also supports metadata tagging, album art, and gapless playback, which helps preserve the listening experience in continuous tracks or albums.

History and licensing: Apple introduced ALAC as part of its music software ecosystem in the mid-2000s. In 2011, Apple open-sourced the ALAC codec and released the source code under an open license, facilitating wider adoption and implementation beyond Apple devices. This move helped position ALAC as a competitive lossless option within the broader digital-audio landscape.

Usage and compatibility: ALAC is natively supported on Apple devices and software, including macOS, iOS, iPadOS, the Music app, and Apple TV. It is also widely supported by third-party media players and some hardware players that handle M4A/ALAC files. Within Apple Music and related services, ALAC is commonly used for lossless audio streams and downloads, providing lossless playback for users who opt into higher-quality audio.