Speech decoder, speech decoding method, program and storage media to improve voice clarity by emphasizing voice tract characteristics using estimated formants

摘要

A code separation/decoding unit restores a vocal tract characteristic sp₁ and a vocal source signal r₁. A vocal tract characteristic modification unit modifies the vocal tract characteristic sp₁ and outputs the modified vocal tract characteristic sp₂. In this method, an emphasized vocal tract characteristic sp₂ is generated to output by applying formant emphasis, using amplification ratios calculated based on estimated formants, directly to the vocal tract characteristic sp₁ for instance. A signal synthesis unit synthesizes the modified vocal tract characteristic sp₂ and the vocal source signal r₁ to generate and output an output voice, s.