ADAPTIVE ENCODED SYSTEM

PURPOSE: To improve the encoding efficiency and tone quality of an adaptive encoding system by encoding digital audio signals inputted from a plurality of channels. CONSTITUTION: Subband filters 11 and 12 input digital audio signals X1(mi) and X2(si) having sampling frequencies fs to a quantizing device 70 by dividing the frequencies fs into B pieces of sampling frequencies fs /B. Quantizers 71 and 72 constituting the quantizing device 70 quantize divided subband audio samples from filters 11 and 12 by using bit assignment information SB11 and SB12 from a third bit assignment unit 60 and supply the quantized samples to a formatting circuit 80 and the circuit 80 outputs the quantized audio samples and bit assignment information CB11, CB12, FB11, FB12, SB11, and SB12 from first, second, and third bit assignment units 40, 50, and 60 after formatting. Therefore, the input digital audio signal encoding efficiency and tone quality of an adaptive encoding system can be improved.