.alac File — Apple Lossless Audio Codec

ALAC (Apple Lossless Audio Codec) is a lossless audio compression format developed by Apple. ALAC compresses audio without any quality loss — decoded output is bit-identical to the original — while typically reducing file sizes by 40-60% compared to uncompressed PCM. Apple open-sourced the codec in 2011 under the Apache License. ALAC is the lossless format native to the Apple ecosystem, supported by iTunes, Apple Music, iPhone, iPad, Mac, Apple TV, HomePod, and AirPlay. Apple Music's lossless streaming tier uses ALAC encoding. The codec supports up to 32-bit sample depth and 384 kHz sample rate across 8 channels. ALAC is typically stored in M4A or CAF containers with appropriate metadata. While FLAC is more widely supported across non-Apple platforms and has a larger user base in the audiophile community, ALAC provides equivalent compression and quality with native Apple ecosystem integration. Many music management tools can convert between ALAC and FLAC without quality loss since both are lossless. The codec is efficient enough for real-time encoding and decoding on mobile devices, enabling lossless streaming and playback without excessive battery drain.