PASC: Precision Adaptive Subband Coding (PASC) is an MPEG-based data reduction method that is used in the Digital Compact Cassette (DCC) is used. The aim of this process is to convert digitized audio into CD-Save sound quality on audio tapes.
PASC achieves this by optimizing two factors that determine hearing ability:
- The first effect considered in PASC is the hearing threshold. The threshold of hearing is the volume at which human hearing begins to function. It is frequency dependent and is characterized by the fact that hearing is more sensitive to medium frequencies than to low or high ones. PASC takes this into account by only processing tones above the hearing characteristic.
- The second effect is volumethat im feeling a certain dynamics subject and changes the hearing threshold.
This means that with louder sounds, the hearing threshold automatically increases. This dynamization of the hearing threshold is also taken into account in PASC. The PASC process is extremely efficient, requiring only a quarter of the time with the same sound quality bitrate across from PCM. PASC uses the MPEG standard and has a bit rate of 384 kbit/s.