/** * @file   ss.c * @author Akinobu LEE * @date   Thu Feb 17 17:19:54 2005 *  * <JA> * @brief  スペクトル負(fù)換 * * 悸狠のスペクトル負(fù)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> *  * $Revision: 1.4 $ *  *//* * Copyright (c) 1991-2006 Kawahara Lab., Kyoto University * Copyright (c) 2000-2005 Shikano Lab., Nara Institute of Science and Technology * Copyright (c) 2005-2006 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 */  j_printerr("Reading Noise Spectrum for SS...");  if ((fp = fopen_readfile(filename)) == NULL) {    j_printerr("Error: SS_load_from_file: cannot open \"%s\"\n", filename);    return(NULL);  }  /* read length */  if (myread(&num, sizeof(int), 1, fp) == FALSE) {    j_printerr("Error: SS_load_from_file: cannot read \"%s\"\n", filename);    return(NULL);  }  /* allocate */  sbuf = (float *)mymalloc(sizeof(float) * num);  /* read data */  if (myread(sbuf, sizeof(float), num, fp) == FALSE) {    j_printerr("Error: SS_load_from_file: cannot read \"%s\"\n", filename);    return(NULL);  }  /* close file */  fclose_readfile(fp);  *slen = num;  j_printerr("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 para [in] parameter * @param slen [out] length of returned buffer *  * @return a newly allocated buffer that contains the calculated spectrum. */float *new_SS_calculate(SP16 *wave, int wavelen, Value para, int *slen){  int fftN, n;  float *bf, *Re, *Im, *spec;  int t, framenum, start, end, k, i;  double x, y;    /* Calculate FFT size */  fftN = 2;  n = 1;  while(para.framesize > fftN){    fftN *= 2; n++;  }#ifdef MFCC_SINCOS_TABLE  /* generate tables */  make_costbl_hamming(para.framesize);  make_fft_table(n);#endif    /* allocate work area */  spec = (float *)mymalloc((fftN + 1) * sizeof(float));  bf = (float *)mymalloc((fftN + 1) * sizeof(float));  Re = (float *)mymalloc((fftN + 1) * sizeof(float));  Im = (float *)mymalloc((fftN + 1) * sizeof(float));  for(i=0;i<fftN;i++) spec[i] = 0.0;    /* Caluculate Sum of Noise Power Spectral */  framenum = (int)((wavelen - para.framesize) / para.frameshift) + 1;  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++) {      bf[k] = (float)wave[i-1];      k++;    }    end = i;    if (para.zmeanframe) {      ZMeanFrame(bf, para.framesize);    }    /* Pre-emphasis */    PreEmphasise(bf, para);    /* Hamming Window */    Hamming(bf, para.framesize);    /* FFT Spectrum */    for (i = 1; i <= para.framesize; i++) {      Re[i-1] = bf[i]; Im[i-1] = 0.0;    }    for (i = para.framesize + 1; i <= fftN; i++) {      Re[i-1] = 0.0;   Im[i-1] = 0.0;    }    FFT(Re, Im, n);    /* Sum noise spectrum */    for(i = 1; i <= fftN; i++){      x = Re[i - 1];  y = Im[i - 1];      spec[i - 1] += sqrt(x * x + y * y);    }  }  /* Calculate average noise spectrum */  for(t=0;t<fftN;t++) {    spec[t] /= (float)framenum;  }  /* return the new spec[] */  free(Im);  free(Re);  free(bf);  *slen = fftN;  return(spec);}