wavpack

WavPack is a completely open audio compression format providing lossless, high-quality lossy, and a unique hybrid compression mode. Although the technology is loosely based on previous versions of WavPack, the new version 4 format has been designed from the ground up to offer unparalleled performance and functionality. In the default lossless mode WavPack acts just like a WinZip compressor for audio files. However, unlike MP3 or WMA encoding which can affect the sound quality, not a single bit of the original information is lost, so there's no chance of degradation. This makes lossless mode ideal for archiving audio material or any other situation where quality is paramount.