lpc2lsp

Functions

int main(int argc, char *argv[])

lpc2lsp [ option ] [ infile ]

-m int
- order of coefficients \((0 \le M)\)
-s double
- sampling rate \((0 < F_s)\)
-k int
- output gain type
  - 0 linear gain
  - 1 log gain
  - 2 without gain
-o int
- output format
  - 0 frequency in rad
  - 1 frequency in cyc
  - 2 frequency in kHz
  - 3 frequency in Hz
-n int
- number of splits of unit circle quadrant \((1 \le S)\)
-i int
- maximum number of iterations \((0 \le N)\)
-d double
- convergence threshold \((0 \le \epsilon)\)
infile str
- double-type LPC coefficients
stdout
- double-type LSP coefficients

The below example extracts 10-th order LSP coefficients from data.d.

frame < data.d | window | lpc -m 10 | lpc2lsp -m 10 > data.lsp

Parameters:

argc – [in] Number of arguments.
argv – [in] Argument vector.

Returns:

0 on success, 1 on failure.

See also

lsp2lpc lspdf

class LinearPredictiveCoefficientsToLineSpectralPairs

Convert linear predictive coefficients to line spectral pairs.

The input is the \(M\)-th order LPC:

\[ \begin{array}{cccc} K, & a(1), & \ldots, & a(M), \end{array} \]

and the output is the \(M\)-th order LSP:

\[ \begin{array}{cccc} K, & \omega(1), & \ldots, & \omega(M). \end{array} \]

The LSP coefficients are obtained by an iterative root finding algorithm.

[1] P. Kabal and R. P. Ramachandran, “The computation of line spectral frequencies using Chebyshev polynomials,” IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. 34, no. 6, pp. 1419-1426, 1986.

Public Functions

LinearPredictiveCoefficientsToLineSpectralPairs(int num_order, int num_split, int num_iteration, double convergence_threshold)

Parameters:

num_order – [in] Order of coefficients, \(M\).
num_split – [in] Number of splits of unit circle quadrant.
num_iteration – [in] Number of iterations.
convergence_threshold – [in] Convergence threshold.

inline int GetNumOrder() const

Returns:: Order of coefficients.

inline int GetNumSplit() const

Returns:: Number of splits.

inline int GetNumIteration() const

Returns:: Number of iterations.

inline double GetConvergenceThreshold() const

Returns:: Convergence threshold.

inline bool IsValid() const

Returns:: True if this object is valid.

bool Run(const std::vector<double> &linear_predictive_coefficients, std::vector<double> *line_spectral_pairs, LinearPredictiveCoefficientsToLineSpectralPairs::Buffer *buffer) const

Parameters:

linear_predictive_coefficients – [in] \(M\)-th order LPC.
line_spectral_pairs – [out] \(M\)-th order LSP.
buffer – [out] Buffer.

Returns:

True on success, false on failure.

bool Run(std::vector<double> *input_and_output, LinearPredictiveCoefficientsToLineSpectralPairs::Buffer *buffer) const

Parameters:

input_and_output – [inout] \(M\)-th order coefficients.
buffer – [out] Buffer.

Returns:

True on success, false on failure.

class Buffer: Buffer for LinearPredictiveCoefficientsToLineSpectralPairs class.