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. This is a very big event for music fans. While the FLAC format is widely used to distribute music in lossless format, it is not compatible with iTunes (or rather iTunes doesn’t accept FLAC files).
Apple created the Apple Lossless codec to be able to provide a lossless format with iTunes, deploying it in April, 2004. In my opinion, they created their own lossless format rather than use FLAC out of the fear that FLAC might have been encumbered by patents, which would leave Apple open to patent trolls. (Microsoft does not support FLAC in their Windows Media Player software either, undoubtedly for the same reason.)
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. I had heard from several classical music labels that Apple had harassed those that had tried to sell in that format some time ago. (It’s worth noting that Kirkville sponsor Hyperion Records recently started selling their music in Apple Lossless format, together with FLAC and MP3, and met with no problems.) 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.
Apple Lossless provides full lossless quality, in files of similar sizes as FLAC. As a lossless codec, there is no loss of sound quality when converting CDs or other master files into this format. Apple Lossless supports high bit rates and sample rates, and according to an Apple forum post, can handle up to 24 bits and 352.8 kHz. (I have converted files in Apple lossless at up to 24/192.) And I note that Gimmell Records is selling Apple Lossless files in up to 24/176.4, as of today.
It will be interesting to see if other software and hardware start offering support for Apple Lossless. If they do, this format could potentially overtake FLAC in the music market.