SPEECH CODING APPARATUS AND SPEECH DECODING APPARATUS EACH HAVING A SCALABLE CONFIGURATION

A speech coding apparatus includes a base layer coder that codes an input signal and generates first coded information. A base layer decoder decodes the first coded information and generates a first decoded signal. The base layer decoder also generates long term prediction information comprising information representing long term correlation of speech or sound. An adder obtains a residual signal representing a difference between the input signal and the first decoded signal. An enhancement layer coder calculates a long term prediction coefficient using the residual signal obtained in the adder and a long term prediction signal fetched from a previous long term prediction signal sequence based on the long term prediction information. The enhancement layer coder further codes the long term prediction coefficient and generates second coded information.