FREQUENCY DOMAIN PARAMETER SEQUENCE GENERATION METHOD, CODING METHOD, DECODING METHOD, FREQUENCY DOMAIN PARAMETER SEQUENCE GENERATION DEVICE, CODING DEVICE, DECODING DEVICE, PROGRAM, AND RECORDING MEDIUM

摘要

The present invention reduces coding distortion of frequency domain coding more than in the prior art and obtains an LSP parameter from a coefficient that is equivalent to a linear prediction coefficient obtained by frequency domain coding, said LSP parameter corresponding to a quantised LSP parameter of a previous frame and used in time domain coding. If p is an integer of 1 or more, a[1], a[2],..., a[p] is a linear prediction coefficient sequence obtained by linear prediction analysis of a sound signal in a prescribed time interval, ω[1], ω[2],..., ω[p] is a frequency domain parameter sequence derived from the linear prediction coefficient sequence a[1], a[2],...,a[p], and the frequency domain parameter sequence ω[1], ω[2],..., ω[p] is input, an LSP linear conversion unit (300) determines a post-conversion frequency domain parameter ~ω[i] value by linear conversion of each ~ω[i] (i=1, 2,..., p) in a post-conversion frequency domain parameter sequence ~ω[1], ~ω[2],..., ~ω[p] on the basis of the relation of the values ω[i] and one or a plurality of frequency domain parameters adjacent to ω[i].