| 摘要 |
The invention relates to a speech signal decoding method comprising decoding information containing at least a sound source signal, a gain, and filter coefficients from a received bit stream, identifying voiced speech and unvoiced speech of a speech signal using the decoded information, performing smoothing processing for at least either one of the decoded gain and the decoded filter coefficients, and
decoding the speech signal by driving a filter having the decoded filter coefficients by an excitation signal obtained by multiplying the decoded sound source signal by the decoded gain using a result of the smoothing processing, wherein said smoothing processing is performed based on the result of said identification. The invention further relates to a speech signal decoding apparatus comprising decoding means for decoding information containing at least a sound source signal, a gain, and filter coefficients from a received bit stream, identification means for identifying voiced speech and unvoiced speech of a speech signal using decoded information, smoothing means for performing smoothing processing for at least either one of the decoded gain and the decoded filter coefficients, and filtering means for decoding the speech signal by driving a filter having the decoded filter coefficients by an excitation signal obtained by multiplying the decoded sound source signal by the decoded gain, using a result of the smoothing processing, wherein said smoothing processing is performed based on the result of said identification.
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