/* Copyright (C) 2003 Epic Games    Written by Jean-Marc Valin   File: preprocess.c   Preprocessor with denoising based on the algorithm by Ephraim and Malah   Redistribution and use in source and binary forms, with or without   modification, are permitted provided that the following conditions are   met:   1. Redistributions of source code must retain the above copyright notice,   this list of conditions and the following disclaimer.   2. Redistributions in binary form must reproduce the above copyright   notice, this list of conditions and the following disclaimer in the   documentation and/or other materials provided with the distribution.   3. The name of the author may not be used to endorse or promote products   derived from this software without specific prior written permission.   THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE   DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE   POSSIBILITY OF SUCH DAMAGE.*/#ifdef HAVE_CONFIG_H#include "config.h"#endif#include <math.h>#include "speex_preprocess.h"#include "misc.h"#include "smallft.h"#define max(a,b) ((a) > (b) ? (a) : (b))#define min(a,b) ((a) < (b) ? (a) : (b))#ifndef M_PI#define M_PI 3.14159263#endif#define SQRT_M_PI_2 0.88623#define LOUDNESS_EXP 2.5#define NB_BANDS 8#define SPEEX_PROB_START_DEFAULT    0.35f#define SPEEX_PROB_CONTINUE_DEFAULT 0.20f#define ZMIN .1#define ZMAX .316#define ZMIN_1 10#define LOG_MIN_MAX_1 0.86859static void conj_window(float *w, int len){   int i;   for (i=0;i<len;i++)   {      float x=4*((float)i)/len;      int inv=0;      if (x<1)      {      } else if (x<2)      {         x=2-x;         inv=1;      } else if (x<3)      {         x=x-2;         inv=1;      } else {         x=4-x;      }      x*=1.9979;      w[i]=(.5-.5*cos(x))*(.5-.5*cos(x));      if (inv)         w[i]=1-w[i];      w[i]=sqrt(w[i]);   }}/* This function approximates the gain function    y = gamma(1.25)^2 * M(-.25;1;-x) / sqrt(x)     which multiplied by xi/(1+xi) is the optimal gain   in the loudness domain ( sqrt[amplitude] )*/static inline float hypergeom_gain(float x){   int ind;   float integer, frac;   static const float table[21] = {      0.82157f, 1.02017f, 1.20461f, 1.37534f, 1.53363f, 1.68092f, 1.81865f,      1.94811f, 2.07038f, 2.18638f, 2.29688f, 2.40255f, 2.50391f, 2.60144f,      2.69551f, 2.78647f, 2.87458f, 2.96015f, 3.04333f, 3.12431f, 3.20326f};         if (x>9.5)      return 1+.1296/x;      integer = floor(2*x);   frac = 2*x-integer;   ind = (int)integer;      return ((1-frac)*table[ind] + frac*table[ind+1])/sqrt(x+.0001f);}static inline float qcurve(float x){   return 1.f/(1.f+.1f/(x*x));}SpeexPreprocessState *speex_preprocess_state_init(int frame_size, int sampling_rate){   int i;   int N, N3, N4;   SpeexPreprocessState *st = (SpeexPreprocessState *)speex_alloc(sizeof(SpeexPreprocessState));   st->frame_size = frame_size;   /* Round ps_size down to the nearest power of two */#if 0   i=1;   st->ps_size = st->frame_size;   while(1)   {      if (st->ps_size & ~i)      {         st->ps_size &= ~i;         i<<=1;      } else {         break;      }   }         if (st->ps_size < 3*st->frame_size/4)      st->ps_size = st->ps_size * 3 / 2;#else   st->ps_size = st->frame_size;#endif   N = st->ps_size;   N3 = 2*N - st->frame_size;   N4 = st->frame_size - N3;      st->sampling_rate = sampling_rate;   st->denoise_enabled = 1;   st->agc_enabled = 0;   st->agc_level = 8000;   st->vad_enabled = 0;   st->dereverb_enabled = 0;   st->reverb_decay = .5;   st->reverb_level = .2;   st->speech_prob_start = SPEEX_PROB_START_DEFAULT;   st->speech_prob_continue = SPEEX_PROB_CONTINUE_DEFAULT;   st->frame = (float*)speex_alloc(2*N*sizeof(float));   st->ps = (float*)speex_alloc(N*sizeof(float));   st->gain2 = (float*)speex_alloc(N*sizeof(float));   st->window = (float*)speex_alloc(2*N*sizeof(float));   st->noise = (float*)speex_alloc(N*sizeof(float));   st->reverb_estimate = (float*)speex_alloc(N*sizeof(float));   st->old_ps = (float*)speex_alloc(N*sizeof(float));   st->gain = (float*)speex_alloc(N*sizeof(float));   st->prior = (float*)speex_alloc(N*sizeof(float));   st->post = (float*)speex_alloc(N*sizeof(float));   st->loudness_weight = (float*)speex_alloc(N*sizeof(float));   st->inbuf = (float*)speex_alloc(N3*sizeof(float));   st->outbuf = (float*)speex_alloc(N3*sizeof(float));   st->echo_noise = (float*)speex_alloc(N*sizeof(float));   st->S = (float*)speex_alloc(N*sizeof(float));   st->Smin = (float*)speex_alloc(N*sizeof(float));   st->Stmp = (float*)speex_alloc(N*sizeof(float));   st->update_prob = (float*)speex_alloc(N*sizeof(float));   st->zeta = (float*)speex_alloc(N*sizeof(float));   st->Zpeak = 0;   st->Zlast = 0;   st->noise_bands = (float*)speex_alloc(NB_BANDS*sizeof(float));   st->noise_bands2 = (float*)speex_alloc(NB_BANDS*sizeof(float));   st->speech_bands = (float*)speex_alloc(NB_BANDS*sizeof(float));   st->speech_bands2 = (float*)speex_alloc(NB_BANDS*sizeof(float));   st->noise_bandsN = st->speech_bandsN = 1;   conj_window(st->window, 2*N3);   for (i=2*N3;i<2*st->ps_size;i++)      st->window[i]=1;      if (N4>0)   {      for (i=N3-1;i>=0;i--)      {         st->window[i+N3+N4]=st->window[i+N3];         st->window[i+N3]=1;      }   }   for (i=0;i<N;i++)   {      st->noise[i]=1e4;      st->reverb_estimate[i]=0.;      st->old_ps[i]=1e4;      st->gain[i]=1;      st->post[i]=1;      st->prior[i]=1;   }   for (i=0;i<N3;i++)   {      st->inbuf[i]=0;      st->outbuf[i]=0;   }   for (i=0;i<N;i++)   {      float ff=((float)i)*.5*sampling_rate/((float)N);      st->loudness_weight[i] = .35f-.35f*ff/16000.f+.73f*exp(-.5f*(ff-3800)*(ff-3800)/9e5f);      if (st->loudness_weight[i]<.01f)         st->loudness_weight[i]=.01f;      st->loudness_weight[i] *= st->loudness_weight[i];   }   st->speech_prob = 0;   st->last_speech = 1000;   st->loudness = pow(6000,LOUDNESS_EXP);   st->loudness2 = 6000;   st->nb_loudness_adapt = 0;   st->fft_lookup = (struct drft_lookup*)speex_alloc(sizeof(struct drft_lookup));   spx_drft_init(st->fft_lookup,2*N);   st->nb_adapt=0;   st->consec_noise=0;   st->nb_preprocess=0;   return st;}void speex_preprocess_state_destroy(SpeexPreprocessState *st){   speex_free(st->frame);   speex_free(st->ps);   speex_free(st->gain2);   speex_free(st->window);   speex_free(st->noise);   speex_free(st->reverb_estimate);   speex_free(st->old_ps);   speex_free(st->gain);   speex_free(st->prior);   speex_free(st->post);   speex_free(st->loudness_weight);   speex_free(st->echo_noise);   speex_free(st->S);   speex_free(st->Smin);   speex_free(st->Stmp);   speex_free(st->update_prob);   speex_free(st->zeta);   speex_free(st->noise_bands);   speex_free(st->noise_bands2);   speex_free(st->speech_bands);   speex_free(st->speech_bands2);   speex_free(st->inbuf);   speex_free(st->outbuf);   spx_drft_clear(st->fft_lookup);   speex_free(st->fft_lookup);   speex_free(st);}static void update_noise(SpeexPreprocessState *st, float *ps, spx_int32_t *echo){   int i;   float beta;   st->nb_adapt++;   beta=1.0f/st->nb_adapt;   if (beta < .05f)      beta=.05f;      if (!echo)   {      for (i=0;i<st->ps_size;i++)         st->noise[i] = (1.f-beta)*st->noise[i] + beta*ps[i];   } else {      for (i=0;i<st->ps_size;i++)         st->noise[i] = (1.f-beta)*st->noise[i] + beta*max(1.f,ps[i]-st->frame_size*st->frame_size*4.0*echo[i]); #if 0      for (i=0;i<st->ps_size;i++)         st->noise[i] = 0;#endif   }}static int speex_compute_vad(SpeexPreprocessState *st, float *ps, float mean_prior, float mean_post){   int i, is_speech=0;   int N = st->ps_size;   float scale=.5f/N;   /* FIXME: Clean this up a bit */   {      float bands[NB_BANDS];      int j;      float p0, p1;      float tot_loudness=0;      float x = sqrt(mean_post);      for (i=5;i<N-10;i++)      {         tot_loudness += scale*st->ps[i] * st->loudness_weight[i];      }      for (i=0;i<NB_BANDS;i++)      {         bands[i]=1e4f;         for (j=i*N/NB_BANDS;j<(i+1)*N/NB_BANDS;j++)         {            bands[i] += ps[j];         }         bands[i]=log(bands[i]);      }            /*p1 = .0005+.6*exp(-.5*(x-.4)*(x-.4)*11)+.1*exp(-1.2*x);      if (x<1.5)         p0=.1*exp(2*(x-1.5));      else         p0=.02+.1*exp(-.2*(x-1.5));      */      p0=1.f/(1.f+exp(3.f*(1.5f-x)));      p1=1.f-p0;      /*fprintf (stderr, "%f %f ", p0, p1);*/      /*p0 *= .99*st->speech_prob + .01*(1-st->speech_prob);      p1 *= .01*st->speech_prob + .99*(1-st->speech_prob);            st->speech_prob = p0/(p1+p0);      */      if (st->noise_bandsN < 50 || st->speech_bandsN < 50)      {         if (mean_post > 5.f)         {            float adapt = 1./st->speech_bandsN++;            if (adapt<.005f)               adapt = .005f;            for (i=0;i<NB_BANDS;i++)            {               st->speech_bands[i] = (1.f-adapt)*st->speech_bands[i] + adapt*bands[i];               /*st->speech_bands2[i] = (1-adapt)*st->speech_bands2[i] + adapt*bands[i]*bands[i];*/               st->speech_bands2[i] = (1.f-adapt)*st->speech_bands2[i] + adapt*(bands[i]-st->speech_bands[i])*(bands[i]-st->speech_bands[i]);            }         } else {            float adapt = 1./st->noise_bandsN++;            if (adapt<.005f)               adapt = .005f;            for (i=0;i<NB_BANDS;i++)            {               st->noise_bands[i] = (1.f-adapt)*st->noise_bands[i] + adapt*bands[i];               /*st->noise_bands2[i] = (1-adapt)*st->noise_bands2[i] + adapt*bands[i]*bands[i];*/               st->noise_bands2[i] = (1.f-adapt)*st->noise_bands2[i] + adapt*(bands[i]-st->noise_bands[i])*(bands[i]-st->noise_bands[i]);            }         }      }      p0=p1=1;      for (i=0;i<NB_BANDS;i++)      {         float noise_var, speech_var;         float noise_mean, speech_mean;         float tmp1, tmp2, pr;         /*noise_var = 1.01*st->noise_bands2[i] - st->noise_bands[i]*st->noise_bands[i];           speech_var = 1.01*st->speech_bands2[i] - st->speech_bands[i]*st->speech_bands[i];*/         noise_var = st->noise_bands2[i];         speech_var = st->speech_bands2[i];         if (noise_var < .1f)            noise_var = .1f;         if (speech_var < .1f)            speech_var = .1f;                  /*speech_var = sqrt(speech_var*noise_var);           noise_var = speech_var;*/         if (speech_var < .05f*speech_var)            noise_var = .05f*speech_var;          if (speech_var < .05f*noise_var)            speech_var = .05f*noise_var;                  if (bands[i] < st->noise_bands[i])            speech_var = noise_var;         if (bands[i] > st->speech_bands[i])            noise_var = speech_var;         speech_mean = st->speech_bands[i];         noise_mean = st->noise_bands[i];         if (noise_mean < speech_mean - 5.f)            noise_mean = speech_mean - 5.f;         tmp1 = exp(-.5f*(bands[i]-speech_mean)*(bands[i]-speech_mean)/speech_var)/sqrt(2.f*M_PI*speech_var);         tmp2 = exp(-.5f*(bands[i]-noise_mean)*(bands[i]-noise_mean)/noise_var)/sqrt(2.f*M_PI*noise_var);         /*fprintf (stderr, "%f ", (float)(p0/(.01+p0+p1)));*/         /*fprintf (stderr, "%f ", (float)(bands[i]));*/         pr = tmp1/(1e-25+tmp1+tmp2);         /*if (bands[i] < st->noise_bands[i])            pr=.01;         if (bands[i] > st->speech_bands[i] && pr < .995)         pr=.995;*/         if (pr>.999f)            pr=.999f;         if (pr<.001f)            pr=.001f;         /*fprintf (stderr, "%f ", pr);*/         p0 *= pr;         p1 *= (1-pr);      }      p0 = pow(p0,.2);      p1 = pow(p1,.2);            #if 1      p0 *= 2.f;      p0=p0/(p1+p0);      if (st->last_speech>20)       {         float tmp = sqrt(tot_loudness)/st->loudness2;         tmp = 1.f-exp(-10.f*tmp);         if (p0>tmp)            p0=tmp;      }      p1=1-p0;#else      if (sqrt(tot_loudness) < .6f*st->loudness2 && p0>15.f*p1)         p0=15.f*p1;      if (sqrt(tot_loudness) < .45f*st->loudness2 && p0>7.f*p1)         p0=7.f*p1;      if (sqrt(tot_loudness) < .3f*st->loudness2 && p0>3.f*p1)         p0=3.f*p1;      if (sqrt(tot_loudness) < .15f*st->loudness2 && p0>p1)         p0=p1;      /*fprintf (stderr, "%f %f ", (float)(sqrt(tot_loudness) /( .25*st->loudness2)), p0/(p1+p0));*/#endif      p0 *= .99f*st->speech_prob + .01f*(1-st->speech_prob);      p1 *= .01f*st->speech_prob + .99f*(1-st->speech_prob);            st->speech_prob = p0/(1e-25f+p1+p0);      /*fprintf (stderr, "%f %f %f ", tot_loudness, st->loudness2, st->speech_prob);*/      if (st->speech_prob > st->speech_prob_start         || (st->last_speech < 20 && st->speech_prob > st->speech_prob_continue))      {         is_speech = 1;         st->last_speech = 0;      } else {         st->last_speech++;         if (st->last_speech<20)           is_speech = 1;      }      if (st->noise_bandsN > 50 && st->speech_bandsN > 50)      {         if (mean_post > 5)         {            float adapt = 1./st->speech_bandsN++;            if (adapt<.005f)               adapt = .005f;            for (i=0;i<NB_BANDS;i++)            {               st->speech_bands[i] = (1-adapt)*st->speech_bands[i] + adapt*bands[i];               /*st->speech_bands2[i] = (1-adapt)*st->speech_bands2[i] + adapt*bands[i]*bands[i];*/               st->speech_bands2[i] = (1-adapt)*st->speech_bands2[i] + adapt*(bands[i]-st->speech_bands[i])*(bands[i]-st->speech_bands[i]);            }         } else {            float adapt = 1./st->noise_bandsN++;            if (adapt<.005f)               adapt = .005f;            for (i=0;i<NB_BANDS;i++)            {               st->noise_bands[i] = (1-adapt)*st->noise_bands[i] + adapt*bands[i];               /*st->noise_bands2[i] = (1-adapt)*st->noise_bands2[i] + adapt*bands[i]*bands[i];*/               st->noise_bands2[i] = (1-adapt)*st->noise_bands2[i] + adapt*(bands[i]-st->noise_bands[i])*(bands[i]-st->noise_bands[i]);            }         }      }   }   return is_speech;}static void speex_compute_agc(SpeexPreprocessState *st, float mean_prior){   int i;   int N = st->ps_size;   float scale=.5f/N;   float agc_gain;   int freq_start, freq_end;   float active_bands = 0;   freq_start = (int)(300.0f*2*N/st->sampling_rate);   freq_end   = (int)(2000.0f*2*N/st->sampling_rate);   for (i=freq_start;i<freq_end;i++)