Because of the low tape speed, the achievable bit rate of DCC is limited. To compensate, DCC uses Precision Adaptive Sub-band Coding (PASC) for audio data compression. PASC was later integrated into the ISO/IEC 11172-3 standard as MPEG-1 Audio Layer I (MP1). Though MP1 allows various bit rates, PASC is fixed at 384 kilobits per second. The bandwidth of a CD recording of approximately 1.4 megabits per second is reduced to 384 kilobits per second, a compression ratio of around 3.68:1. The difference in quality between PASC and the 5:1 compression used by early versions of ATRAC in the original MiniDisc is largely a subjective matter.