b2mc
Functions
-
int main(int argc, char *argv[])
b2mc [ option ] [ infile ]
-m int
order of coefficients \((0 \le M)\)
-a double
all-pass constant \((|\alpha| < 1)\)
infile str
double-type MLSA digital filter coefficients
stdout
double-type mel-cepstral coefficients
The below example converts MLSA digital filter coefficients into mel-cepstral coefficients:
b2mc < data.b > data.mc
The converted mel-cepstral coefficients can be reverted by
mc2b < data.mc > data.b
- Parameters
argc – [in] Number of arguments.
argv – [in] Argument vector.
- Returns
0 on success, 1 on failure.
-
class sptk::MlsaDigitalFilterCoefficientsToMelCepstrum
Convert MLSA digital filter coefficients to mel-cepstral coefficients.
The input is the \(M\)-th order MLSA digital filter coefficients:
\[ \begin{array}{cccc} b(0), & b(1), & \ldots, & b(M), \end{array} \]and the output is the \(M\)-th order mel-cepstral coefficients:\[ \begin{array}{cccc} \tilde{c}(0), & \tilde{c}(1), & \ldots, & \tilde{c}(M). \end{array} \]The mel-cepstral coefficients can be obtained by the linear transformation of the MLSA digital filter coefficients:\[ \tilde{\boldsymbol{c}} = \boldsymbol{A}\boldsymbol{b}, \]where\[\begin{split}\begin{eqnarray} \boldsymbol{A} &=& \left[ \begin{array}{ccccc} 1 & \alpha & 0 & \cdots & 0 \\ 0 & 1 & \alpha & \ddots & \vdots \\ 0 & 0 & 1 & \ddots & 0 \\ \vdots & \vdots & \ddots & \ddots & \alpha \\ 0 & 0 & \cdots & 0 & 1 \\ \end{array} \right], \\ \tilde{\boldsymbol{c}} &=& \left[ \begin{array}{cccc} \tilde{c}(0) & \tilde{c}(1) & \cdots & \tilde{c}(M) \end{array} \right]^{\mathsf{T}}, \\ \boldsymbol{b} &=& \left[ \begin{array}{cccc} b(0) & b(1) & \cdots & b(M) \end{array} \right]^{\mathsf{T}}. \end{eqnarray}\end{split}\]The transformation is implemented with low computational complexity as follows:\[\begin{split} \tilde{c}(m) = \left\{ \begin{array}{ll} b(m), & m = M \\ b(m) + \alpha b(m + 1). & 0 \le m < M \end{array} \right. \end{split}\][1] K. Tokuda, T. Kobayashi, T. Chiba, and S. Imai, “Spectral estimation of speech by mel-generalized cepstral analysis,” Electronics and Communications in Japan, part 3, vol. 76, no. 2, pp. 30-43, 1993.
Public Functions
-
MlsaDigitalFilterCoefficientsToMelCepstrum(int num_order, double alpha)
- Parameters
num_order – [in] Order of coefficients, \(M\).
alpha – [in] Frequency warping factor, \(\alpha\).
-
inline int GetNumOrder() const
- Returns
Order of coefficients.
-
inline double GetAlpha() const
- Returns
Frequency warping factor.
-
inline bool IsValid() const
- Returns
True if this object is valid.
-
bool Run(const std::vector<double> &mlsa_digital_filter_coefficients, std::vector<double> *mel_cepstrum) const
- Parameters
mlsa_digital_filter_coefficients – [in] \(M\)-th order MLSA digital filter coefficients.
mel_cepstrum – [out] \(M\)-th order mel-cepstral coefficients.
- Returns
True on success, false on failure.
-
bool Run(std::vector<double> *input_and_output) const
- Parameters
input_and_output – [inout] \(M\)-th order coefficients.
- Returns
True on success, false on failure.
-
MlsaDigitalFilterCoefficientsToMelCepstrum(int num_order, double alpha)