If you are an Apple user there is a very slim chance you have used ALAC files on your various components.
ALAC or Apple Lossless Audio Codec is a lossless audio codec (duh). It compresses music down from their original size on a CD to about half of that size without any change in audio fidelity (the two files are mathematically equivalant); compare this to the mp3 (or ogg or aac or …) where the two files, though very different in size, are not the same sonically speaking (the conversion equation leaves a remainder which is thrown out and thus lost). Audio
snobsphiles (myself included) seek out lossless compression formats over lost (or lossy) formats in pursuit of sound qualities nearer to the original master recordings. Suffice it to say, it’s a niche market.
Apple developed their own lossless codec back in 2004 (or at least introduced it then). FLAC (the Free Lossless Audio Codec) was introduced just a few years before in 2001, so perhaps this was part of Apple’s motivation. In terms of math and in terms of sound there is no fundamental reason to select one of these two codecs over the other: they will sound identical if from the same source and can be interconverted indefinitely with no change to the music there contained.
Until recently, however, only one of these was freely available and open to the public (open source). Just a few days ago Apple released the source code for ALAC under the Apache license. (FLAC has open under the GNU GPL since it’s introduction.) (This is about the best article currently available on the Apple announcement.)
For those of us who use software which is not owned by Apple we have still been able to play ALAC files (or convert them to FLAC) since about March of 2005 (thanks to two clever C programmers—read about that here). (I wrote an article on converting ALAC and other formats to FLAC on Ubuntu.)
I have no ALAC currently in my collection. Since ALAC was held by Apple and only functional on Apple software and devices by default it would have made a poor choice for my larger music collection since it has always been my intention to use that music on all of my devices. I even went so far as to install Rockbox on my iPod Classic so that I could enjoy my FLAC files on that device.
I just don’t see this open-sourcing of ALAC as likely to effect many folks. It may have some minor impact on the larger acceptance of FLAC if Apple continues to dis-support FLAC on their operating systems, software, and devices. Then again this could well be a sign that Apple will finally begin supporting (or at least no longer actively dis-supporting) FLAC. (Dream with me.)
The only thing I really dislike about ALAC is the lack of conformity and sense in the file extension. Typically Apple uses the m4a extension. This is because they put the file within the mp4 wrapper. Unfortunately m4a is not an accepted file extension under the mp4 specifications. It’s also possible that you will find an AAC file (remember that’s the extension they use for their lost compression format). Keep in mind there is no programmatic relationship between AAC and ALAC; this is a bad practice and is to be avoided.
I suppose they could use either ALE or ALAC but I don’t think I’ve ever seen them. So, yes, typically they use the unspecified (We made it up!) file extension mp4, and that wouldn’t be all that bad except that mp4 is a wrapper and you can put anything you’d like in it; like an AAC. So really it’s anybody’s guess if you have a lossless or a lost file.
Of course this isn’t a criticism of the specification but rather merely a criticism of the deployment thereof.
Anyway, that’s the news. Probably you won’t care. If they have some clever political agenda for this maneuver it’s beyond me at present. We shall see what the future holds.