Yasushi Nakajima

Audio signal subband encoder

There is provided an audio signal subband encoder which attains improved quality of sound by controlling allocation of the number of quantization bits to subband signals on the basis of an evaluation function combining the noise-to-mask ratio criterion with noise-to-signal ratio criterion in order to lessen the influence of the application error of the auditory masking rule such as the aliasing distortion of subband filters.

Audio subband encoded signal decoder

An audio subband encoded signal decoder which, when an error occurs in an audio subband encoded signal of a plurality of pieces of data, conceals the error in accordance with the contents of the data involving the error and the occurrence of the error in consideration of the degree of influence on a possible reproduced sound quality to thereby improve the sound quality.