The ALAC (Apple Lossless Audio Codec) file format is a lossless audio compression format developed by Apple Inc. It's designed to reduce the file size of audio recordings without sacrificing any audio quality. Unlike lossy formats like MP3 or AAC, ALAC preserves all the original audio data, allowing for perfect reconstruction of the original audio signal during playback. This makes it ideal for archiving music collections, as it ensures that no sonic detail is lost. ALAC files typically offer compression ratios of around 40-60% compared to the original uncompressed audio (e.g., WAV or AIFF). While ALAC was initially proprietary, Apple released the codec as open source in 2011, leading to wider adoption across various platforms and software. It is commonly used within the Apple ecosystem (iTunes, iOS devices) but is also supported by many other audio players and devices. The file extension associated with ALAC is '.alac'.