SUB BAND ENCODING/DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To improve tone quality when it is a low bit rate in a sub band encoding/decoding method which is used to compand various digital audio signals. SOLUTION: A digital audio signal is inputted to a sub band dividing filter bank 101. A band division processing is performed by using sub band dividing filters G0(z)110-G13(z)123 which are reduced to 14 pieces of unequal band dividing filters according to an auditory characteristic of a user. Down-samplers 130-143 perform a thinning-out processing and a quantizing processing part 102 quantizes the digital audio signal, and then it is outputted in a bit stream. It is possible to improve decoding accuracy of a sub band signal and tone quality of the digital audio signal which is decoded and played back by reducing the number of scale factors in the stream of an encoder output and by increasing sample assigned bit number.