Audio compression technologies reduce the data size using a variety of digital signal processing technologies without any loss of sound quality. They also consider human auditory characteristics for the purpose. Audio compression technologies reduce the data size either by not recording the sounds that are difficult for humans to hear, by transforming them into other sounds or by completely eliminating them.
Several types of audio compression technologies are in use and include MP2 systems, MP3 systems, PAC, VQF, Windows WMA systems, TAC systems and sound cards. PAC (Perceptive Audio Coding) is an audio compression technology developed by Lucent Technologies and implemented by Celestialtech. The encoder-database-player program is known as Audiolib 1.0.
The encoding speed of the technology is high, comparable with real-time or even better. The sound quality is like that of the best of MP3 and is better than VQF. The file-format used by Audiolib is unique and no other players would play the files. However, files and databases can be imported or exported between PAC programs. The preferred file size is 128 kbps.
PAC Systems include EAC 081b Ripper and the preferred encoder is AUDIOLIB 1.0.