wav2mfcc.c File Reference

Convert speech waveform to parameter vector sequence. More...

#include <julius.h>
#include <sys/stat.h>

Include dependency graph for wav2mfcc.c:

Go to the source code of this file.

Functions
void	init_para (Value *para)
HTK_Param *	new_wav2mfcc (SP16 speech[], int speechlen)

---

Detailed Description

Convert speech waveform to parameter vector sequence.

Author:

Akinobu Lee

Date:

Sun Sep 18 19:40:34 2005

Parameter vector sequence extraction of input speech is done here. Only parameter format of MFCC_{0|E}_D[_Z][_N] with {25|26} dimensions can be extracted within Julius/Julian, so acoustic model for recognition should be trained by one of these parameter types. You can specify other parameters such as window size, frame shift, high/low frequency cut-off via runtime options. At startup, Julius will check for the parameter types of acoustic model if it conforms the limitation, and determine whether other additional processing is needed such as Cepstral Mean Normalization.

Functions below are used to convert fully buffered whole sentence utterance, and typically used for audio file input. When input is concurrently processed with recognition process at 1st pass, in case of microphone input, the MFCC computation will be done within functions in realtime-1stpass.c instead of these.

Revision

1.3

Definition in file wav2mfcc.c.

---

Function Documentation

void init_para (  Value *  para  )

Set configuration parameters for MFCC computation. Parameters: para  [out] feature extraction parameters Definition at line 72 of file wav2mfcc.c. Referenced by new_wav2mfcc(), and RealTimeInit().

HTK_Param* new_wav2mfcc (  SP16  speech[], int  speechlen )

Extract MFCC parameters with sentence CMN from given waveform. Parameters: speech  [in] buffer of speech waveform speechlen  [in] length of speech in samples Returns: pointer to newly allocated parameter structure data with extracted MFCC vector sequence. Definition at line 129 of file wav2mfcc.c. Referenced by main_recognition_loop().

---