Apple’s Apple Lossless Codec, or ALAC, used to create lossless music files that are compatible, has gone open source, and is available under the Apache license. Details can be found at .

The Apple Lossless Audio Codec (ALAC) is an audio codec developed by Apple and supported on iPhone, iPad, most iPods, Mac and iTunes.  ALAC is a data compression method which reduces the size of audio files with no loss of information.  A decoded ALAC stream is bit-for-bit identical to the original uncompressed audio file.

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.

On his “Kirkville” blog (, author and reviewer Kirk McElhearn “this is a very big event for music fans. While the FLAC format is widely used to distribute music in lossless format, it’s not compatible with iTunes (or rather iTunes doesn’t accept FLAC files), he adds.

“Very little music is currently sold in Apple Lossless format, and music distributed in FLAC format needs to be converted to ALAC for iTunes compatibility – many programs can do this, including the free XLD, but it’s an annoying additional step,” writes McElhearn. “… “Now, with ALAC being open source, it is likely that we’ll see much more music sold is this format; I would expect any online dealer of lossless files to offer this format in addition to FLAC, because so many people use iTunes, and these files can be added to an iTunes library immediately with no conversion.”

— Dennis Sellers