wav2mfcc-buffer.c File Reference

Convert speech inputs into MFCC parameter vectors (per utterance). More...

#include <sent/stddefs.h>
#include <sent/mfcc.h>

Include dependency graph for wav2mfcc-buffer.c:

Go to the source code of this file.

Functions
void	make_costbl_hamming (int framesize)
void	make_fft_table (int n)
void	make_costbl_makemfcc (int fbank_num, int mfcc_dim)
void	make_sintbl_wcep (int lifter, int mfcc_dim)
int	Wav2MFCC (SP16 *wave, float **mfcc, Value para, int nSamples, float *ssbuf, int ssbuflen)
float	CalcLogRawE (float *wave, int framesize)
void	ZMeanFrame (float *wave, int framesize)
void	Hamming (float *wave, int framesize)
void	PreEmphasise (float *wave, Value para)
void	WeightCepstrum (float *mfcc, Value para)
float	Mel (int k, float fres)
FBankInfo	InitFBank (Value para)
void	FreeFBank (FBankInfo fb)
void	MakeFBank (float *wave, double *fbank, FBankInfo fb, Value para, float *ssbuf)
void	MakeMFCC (double *fbank, float *mfcc, Value para)
float	CalcC0 (double *fbank, Value para)
void	NormaliseLogE (float **mfcc, int frame_num, Value para)
void	Delta (float **c, int frame, Value para)
void	Accel (float **c, int frame, Value para)
void	FFT (float *xRe, float *xIm, int p)
void	CMN (float **mfcc, int frame_num, int dim)
Variables
static double *	costbl_hamming
	Cos table for hamming window.
static int	costbl_hamming_len = 0
	Length of above.
static double *	costbl_fft
	Cos table for FFT.
static double *	sintbl_fft
	Sin table for FFT.
static int	tbllen = 0
	Length of above.
static double *	costbl_makemfcc
	Cos table for DCT.
static int	costbl_makemfcc_len = 0
	Length of above.
static double *	sintbl_wcep
	Sin table for cepstrum weighting.
static int	sintbl_wcep_len = 0
	Length of above.
static float	sqrt2var
	Work area that holds value of sqrt(2.0) / fbank_num.

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Detailed Description

Convert speech inputs into MFCC parameter vectors (per utterance).

Author:

Akinobu LEE

Date:

Thu Feb 17 17:43:35 2005

This file contains functions to convert the whole speech input to MFCC vector array. The frame-wise MFCC computation needed for real-time recognition is defined in wav2mfcc-pipe.c.

The supported format is MFCC[_0][_E][_D][_A][_Z].

Revision

1.2

Definition in file wav2mfcc-buffer.c.

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Function Documentation

void make_costbl_hamming (  int  framesize  )

Generate table for hamming window. Parameters: framesize  [in] window size Definition at line 74 of file wav2mfcc-buffer.c. Referenced by InitFBank(), and new_SS_calculate().

void make_fft_table (  int  n  )

Build tables for FFT. Parameters: n  [in] 2^n = FFT point Definition at line 105 of file wav2mfcc-buffer.c. Referenced by InitFBank(), and new_SS_calculate().

void make_costbl_makemfcc (  int  fbank_num, int  mfcc_dim )

Generate table for DCT operation to make mfcc from fbank. Parameters: fbank_num  [in] number of filer banks mfcc_dim  [in] number of dimensions in MFCC Definition at line 138 of file wav2mfcc-buffer.c. Referenced by InitFBank().

void make_sintbl_wcep (  int  lifter, int  mfcc_dim )

Generate table for weighing cepstrum. Parameters: lifter  [in] cepstral liftering coefficient mfcc_dim  [in] number of dimensions in MFCC Definition at line 176 of file wav2mfcc-buffer.c. Referenced by InitFBank().

int Wav2MFCC (  SP16 *  wave, float **  mfcc, Value  para, int  nSamples, float *  ssbuf, int  ssbuflen )

Convert wave data to MFCC. Also does spectral subtraction if ssbuf specified. Parameters: wave  [in] waveform data mfcc  [out] buffer to store the resulting MFCC parameter vector [t][0..veclen-1], should be already allocated para  [in] configuration parameters nSamples  [in] length of waveform data ssbuf  [in] buffer that holds noise spectrum to be subtracted from input, or NULL if not use spectral subtraction ssbuflen  [in] length of above, ignored when ssbuf is NULL Returns: the number of processed frames. Definition at line 217 of file wav2mfcc-buffer.c. Referenced by new_wav2mfcc().

float CalcLogRawE (  float *  wave, int  framesize )

Calculate Log Raw Energy. Parameters: wave  [in] waveform data in the current frame framesize  [in] frame size Returns: the calculated log raw energy. Definition at line 316 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

void ZMeanFrame (  float *  wave, int  framesize )

Remove DC offset per frame Parameters: wave  [i/o] waveform data in the current frame framesize  [in] frame size Definition at line 337 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

void Hamming (  float *  wave, int  framesize )

Apply hamming window. Parameters: wave  [i/o] waveform data in the current frame framesize  [in] frame size Definition at line 354 of file wav2mfcc-buffer.c. Referenced by new_SS_calculate(), Wav2MFCC(), and WMP_calc().

void PreEmphasise (  float *  wave, Value  para )

Apply pre-emphasis filter. Parameters: wave  [i/o] waveform data in the current frame para  [in] configuration parameters Definition at line 374 of file wav2mfcc-buffer.c. Referenced by new_SS_calculate(), Wav2MFCC(), and WMP_calc().

void WeightCepstrum (  float *  mfcc, Value  para )

Re-scale cepstral coefficients. Parameters: mfcc  [i/o] a MFCC vector para  [in] configuration parameters Definition at line 389 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

float Mel (  int  k, float  fres )

Return mel-frequency. Parameters: k  [in] channel number of filter bank fres  [in] constant value computed by "1.0E7 / (para.smp_period * fb.fftN * 700.0)" Returns: the mel frequency. Definition at line 423 of file wav2mfcc-buffer.c. Referenced by InitFBank().

FBankInfo InitFBank (  Value  para  )

Build filterbank information and generate tables for MFCC comptutation. Parameters: para  [in] configuration parameters Returns: the generated filterbank information. Definition at line 435 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_init().

void FreeFBank (  FBankInfo  fb  )

Free FBankInfo. Parameters: fb  [in] filterbank information Definition at line 529 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC().

void MakeFBank (  float *  wave, double *  fbank, FBankInfo  fb, Value  para, float *  ssbuf )

Convert wave -> (spectral subtraction) -> mel-frequency filterbank Parameters: wave  [in] waveform data in the current frame fbank  [out] the resulting mel-frequency filterbank fb  [in] filterbank information para  [in] configuration parameters ssbuf  [in] noise spectrum, or NULL if not apply subtraction Definition at line 547 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

void MakeMFCC (  double *  fbank, float *  mfcc, Value  para )

Apply DCT to filterbank to make MFCC. Parameters: fbank  [in] filterbank mfcc  [out] output MFCC vector para  [in] configuration parameters Definition at line 607 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

float CalcC0 (  double *  fbank, Value  para )

Calculate 0'th cepstral coefficient. Parameters: fbank  [in] filterbank para  [in] configuration parameters Returns: Definition at line 644 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC(), and WMP_calc().

void NormaliseLogE (  float **  mfcc, int  frame_num, Value  para )

Normalise log energy Parameters: mfcc  [i/o] array of MFCC vectors frame_num  [in] number of frames para  [in] configuration parameters Definition at line 663 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC().

void Delta (  float **  c, int  frame, Value  para )

Calculate delta coefficients Parameters: c  [i/o] MFCC vectors, in which the delta coeff. will be appended. frame  [in] number of frames para  [in] configuration parameters Definition at line 695 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC().

void Accel (  float **  c, int  frame, Value  para )

Calculate acceleration coefficients. Parameters: c  [i/o] MFCC vectors, in which the delta coeff. will be appended. frame  [in] number of frames para  [in] configuration parameters Definition at line 744 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC().

void FFT (  float *  xRe, float *  xIm, int  p )

Apply FFT Parameters: xRe  [i/o] real part of waveform xIm  [i/o] imaginal part of waveform p  [in] 2^p = FFT point Definition at line 782 of file wav2mfcc-buffer.c. Referenced by MakeFBank(), and new_SS_calculate().

void CMN (  float **  mfcc, int  frame_num, int  dim )

Cepstrum Mean Normalization (buffered) Cepstral mean will be computed within the given MFCC vectors. Parameters: mfcc  [i/o] array of MFCC vectors frame_num  [in] number of frames dim  [in] total dimension of MFCC vectors Definition at line 835 of file wav2mfcc-buffer.c. Referenced by Wav2MFCC().

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