The Apple Lossless Audio Codec project contains the sources for
the ALAC encoder and decoder. Also included is an example command
line utility, called alacconvert, to read and write audio data
to/from Core Audio Format (CAF) and WAVE files. A description of a
‘magic cookie’ for use with files based on the ISO base media file
format (e.g. MP4 and M4A) is included as well.