ALAC is an extension of files used in Apple operating systems. ALAC files are used to store audio data and are most often associated with iTunes. Data stored in such files is generated based on the ALAC (Apple Lossless Audio Codec) codec. It is a lossless format, which allows you to obtain the same sound that was stored in the original audio data.

After the codec was developed in 2004, it was the exclusive property of Apple. Since 2011, the codec has been released as an oper source technology, free of license fees.