/** * @file   ss.c *  * <JA> * @brief  スペクトル負換 * * 悸狠のスペクトル負換は wav2mfcc-buffer.c および wav2mfcc-pipe.c で * 乖われますˉここでは士堆スペクトルの夸年とファイルI/Oのみ年盜されていますˉ * </JA> *  * <EN> * @brief  Spectral subtraction * * The actual subtraction will be performed in wav2mfcc-buffer.c and * wav2mfcc-pipe.c.  These functions are for estimating average spectrum * of audio input, and file I/O for that. * </EN> *  * @author Akinobu LEE * @date   Thu Feb 17 17:19:54 2005 * * $Revision: 1.3 $ *  *//* * Copyright (c) 1991-2007 Kawahara Lab., Kyoto University * Copyright (c) 2000-2005 Shikano Lab., Nara Institute of Science and Technology * Copyright (c) 2005-2007 Julius project team, Nagoya Institute of Technology * All rights reserved */#include <sent/stddefs.h>#include <sent/mfcc.h>/**  * Binary read function with byte swaping (assume file is BIG ENDIAN) *  * @param buf [out] read data * @param unitbyte [in] size of a unit in bytes * @param unitnum [in] number of unit to be read * @param fp [in] file pointer */static booleanmyread(void *buf, size_t unitbyte, int unitnum, FILE *fp){  size_t tmp;  if ((tmp = myfread(buf, unitbyte, unitnum, fp)) < (size_t)unitnum) {    return(FALSE);  }#ifndef WORDS_BIGENDIAN  swap_bytes(buf, unitbyte, unitnum);#endif  return(TRUE);}/**  * Load a noise spectrum from file. *  * @param filename [in] path name of noise spectrum file * @param slen [out] length of the returned buffer *  * @return a newly allocated buffer that holds the loaded noise spectrum. */float *new_SS_load_from_file(char *filename, int *slen){  FILE *fp;  int num;  float *sbuf;  /* open file */  jlog("Stat: ss: reading Noise Spectrum for SS\n");  if ((fp = fopen_readfile(filename)) == NULL) {    jlog("Error: ss: failed to open \"%s\"\n", filename);    return(NULL);  }  /* read length */  if (myread(&num, sizeof(int), 1, fp) == FALSE) {    jlog("Error: ss: failed to read \"%s\"\n", filename);    return(NULL);  }  /* allocate */  sbuf = (float *)mymalloc(sizeof(float) * num);  /* read data */  if (myread(sbuf, sizeof(float), num, fp) == FALSE) {    jlog("Error: ss: failed to read \"%s\"\n", filename);    return(NULL);  }  /* close file */  fclose_readfile(fp);  *slen = num;  jlog("Stat: ss: done\n");  return(sbuf);}/**  * Compute average spectrum of audio input. * This is used to estimate a noise spectrum from input samples. *  * @param wave [in] input audio data sequence * @param wavelen [in] length of above * @param slen [out] length of returned buffer * @param w [i/o] MFCC calculation work area * @param para [in] parameter *  * @return a newly allocated buffer that contains the calculated spectrum. */float *new_SS_calculate(SP16 *wave, int wavelen, int *slen, MFCCWork *w, Value *para){  float *spec;  int t, framenum, start, end, k, i;  double x, y;    /* allocate work area */  spec = (float *)mymalloc((w->fb.fftN + 1) * sizeof(float));  for(i=0;i<w->fb.fftN;i++) spec[i] = 0.0;    /* Caluculate sum of noise power spectrum */  framenum = (int)((wavelen - para->framesize) / para->frameshift) + 1;  if (framenum < 1) {    jlog("Error: too short to get noise spectrum: length < 1 frame\n");    jlog("Error: no SS will be performed\n");    *slen = w->fb.fftN;    return spec;  }      start = 1;  end = 0;  for (t = 0; t < framenum; t++) {    if (end != 0) start = end - (para->framesize - para->frameshift) - 1;    k = 1;    for (i = start; i <= start + para->framesize; i++) {      w->bf[k] = (float)wave[i-1];      k++;    }    end = i;    if (para->zmeanframe) {      ZMeanFrame(w->bf, para->framesize);    }    /* Pre-emphasis */    PreEmphasise(w->bf, para->framesize, para->preEmph);    /* Hamming Window */    Hamming(w->bf, para->framesize, w);    /* FFT Spectrum */    for (i = 1; i <= para->framesize; i++) {      w->fb.Re[i-1] = w->bf[i]; w->fb.Im[i-1] = 0.0;    }    for (i = para->framesize + 1; i <= w->fb.fftN; i++) {      w->fb.Re[i-1] = 0.0;   w->fb.Im[i-1] = 0.0;    }    FFT(w->fb.Re, w->fb.Im, w->fb.n, w);    /* Sum noise spectrum */    for(i = 1; i <= w->fb.fftN; i++){      x = w->fb.Re[i - 1];  y = w->fb.Im[i - 1];      spec[i - 1] += sqrt(x * x + y * y);    }  }  /* Calculate average noise spectrum */  for(t=0;t<w->fb.fftN;t++) {    spec[t] /= (float)framenum;  }  /* return the new spec[] */  *slen = w->fb.fftN;  return(spec);}