Apple made its lossless audio format open source, allowing for others to view and change the code for use in their own software and tools.
As Daring Fireball notes, the format — which goes by the name, Apple Lossless Audio Codec (or ALAC) — adopted the Apache licence last week.
ALAC was first introduced to Apple's Mac OS X Core Audio framework in 2004, where most users saw it as part of iTunes 4.5. It let users rip a CD into smaller compressed files without reduction in quality. Still, the resulting files are considerably larger than the more ubiquitous MP3, AAC and WMA formats, which compress music tracks even further at the expense of lower fidelity.
It also rivals the Free Lossless Audio Codec (FLAC), another lossless codec, that's been open and royalty free from the start, but is not supported on Apple's portable devices.
ALAC-formatted audio tracks can be played back on software and hardware that support it, which for Apple included things like iTunes and QuickTime, along with the company's iPod — and later iOS — products, and AirPort Express hardware through AirPlay.
As Ars Technica notes, it took developers about a year to reverse engineer the technology to add support for ALAC files in their own software. That includes audio playback software like VLC, Boxee and TapeDeck, which are now able to make use of the official code.