True Audio, or TTA, is a lossless audio compressor. It is designed to be simply and is offered up for free real-time use, maintaining good compression ratios (for lossless that is) and high speeds. It is open source, and it has performed favorably against other open source competitors when tested. TTA performs lossless compression on multichannel 8, 16 and 24-bit data of WAV audio files, with varied compression ratios, generally from 30% - 70% of the original based on the content itself.
The TTA lossless audio codec claims to allow the storing of up to 20 audio CDs worth of music on a single DVD-R disc, retaining the original CD quality audio, while also offering the use of ID3 tags. TTA source code and binaries are freely available and distributed under Open Source licenses. Since TTA is a lossless audio codec, it cannot offer the file sizes achieved by compressed MP3 files or other lossy compression formats. This is due to the fact that TTA encoded audio can be decoded 100% unchanged from the source.
Lossy compression on the other hand removes data permanently from the audio stream that cannot be recovered, hence the reason why decent quality full-length MP3 tracks can be around 4MB in size.