Patent ID: 8099291

Claim:
A signal decoding apparatus that decodes coded information constructed in a plurality of layers, the signal decoding apparatus comprising: a decoding section that decodes the coded information of each layer to generate a plurality of decoded signals; an addition section that adds each of said decoded signals to generate a plurality of addition signals; a storage section that stores each of a plurality of addition signals of a previous frame; a synthesis processing section that calculates linear predictive coefficients by performing a linear predictive coefficient (LPC) analysis of the addition signals of the previous frame stored in the storage section and addition signals of a current frame generated by the addition section, and performs synthesis processing of decoded signals of the current frame using the linear predictive coefficients and the addition signals of the previous frame stored in the storage section; and a control section that controls whether or not to perform the synthesis processing by said synthesis processing section based on a presence or non-presence of the coded information of each layer within the previous frame, wherein: when the number of layers of coded information of the current frame falls below that of the previous frame, the synthesis processing section recalculates the linear predictive coefficients using decoded signals of a lower layer than a layer where coded information is lost, and performs the synthesis processing of decoded signals of the current frame using the recalculated linear predictive coefficients and the addition signals of the previous frame stored in the storage section.