Monkey's Audio
Monkey’s Audio is a lossless audio compression codec. Unlike lossy methods such as MP3, Ogg Vorbis, or LQT that permanently discard quality to save space, Monkey’s Audio only makes perfect, bit-for-bit copies of your music. That means it always sounds perfect – exactly the same as the original. Even though the sound is perfect, it still saves a lot of space.The other great thing is that you can always decompress your Monkey's Audio files back to the exact, original files. That way, you'll never have to recopy your CD collection to switch formats, and you'll always be able to recreate the original music CD if something ever happens to yours.
Other lossless audio compression methods are: SHN (Shorten) and FLAC.
