ADAPTIVE ENCODING SYSTEM

PURPOSE: To improve encoding efficiency and audio quality by adaptively encoding input digital audio signals inputted from plural channels based on recognition entropy for respective input signals. CONSTITUTION: Respective sub band filters 11 and 12 filter the input signals and output samples to a quantization device 60. In the meantime, a recognition parameter calculation device 20 calculates SMR data SMR1 and SMR2, sound pressure levels P1 and P2 and mask threshold values M1 and M2 from the input signals of 2Ch, the SMRs 1 and 2 are supplied to a bit allocation unit 50 and Pi and P2 and M1 and M2 are supplied to a calculation device 30. The calculation device 30 calculates the recognition entropy PE1 and PE2, the average value and the standard deviation based on input data from the calculation device 20 and inputs them to the bit allocation unit 40. The unit 40 decides bits for respective frames based on the PE1 and PE2 or the like inputted from the calculation device 30 and outputs bit allocation information to the unit 50 and a formatting circuit 70.