Patent ID: 7650278

Claim:
A digital signal encoding method, comprising: preparing a plurality of lookup tables storing numbers of allocated bits used to encode frequency bands of an input signal in a predetermined number of addresses; dividing the input signal in a time domain into signals in predetermined frequency bands; calculating address values of the predetermined frequency bands; selecting one of the plurality of lookup tables according to a characteristic of the input signal, the selected lookup table being used for all of the predetermined frequency bands of the input signal, the characteristic of the input signal being the number of frequency bands among the frequency bands of the input signal, whose occupancy rate is less than or more than a predetermined standard value; extracting the numbers of allocated bits of addresses having the calculated address values from the selected lookup table with respect to the predetermined frequency bands; allocating the extracted numbers of bits to the predetermined frequency bands; and generating a bitstream by quantizing the input signal according to the numbers of allocated bits.