LPAC is a codec (coder / decoder) for  lossless compression of digital audio
files. "Lossless" means that any compressed file can be decompressed in a way
it will be bit-wise identical with the original. This is the main advantage
of LPAC compared to lossy formats like MP3, WMA or RealAudio. On the other
hand, lossy codecs can achieve higher compression ratios. For example, MP3 at
128 kbit/s achieves a (fixed) compression ratio of 11, whereas LPAC's
compression ratios range from 1.5 to 4, strongly depending on the audio
material. Typically they are around 2 for pop music and 2.5 for classical
music. This may not seem much, but remember you will get back every single
bit, no matter how often you subsequently compress and decompress a file. It
is true that general archivers (Zip, LZH, gzip) are lossless, too, but they
often achieve nearly no compression on audio files.