static void preprocess_analysis(SpeexPreprocessState *st, spx_int16_t *x)
{
int i;
int N = st->ps_size;
int N3 = 2*N - st->frame_size;
int N4 = st->frame_size - N3;
float *ps=st->ps;
/* 'Build' input frame */
for (i=0;i<N3;i++)
st->frame[i]=st->inbuf[i];
for (i=0;i<st->frame_size;i++)
st->frame[N3+i]=x[i];
/* Update inbuf */
for (i=0;i<N3;i++)
st->inbuf[i]=x[N4+i];
/* Windowing */
for (i=0;i<2*N;i++)
st->frame[i] *= st->window[i];
/* Perform FFT */
spx_drft_forward(st->fft_lookup, st->frame);
/* Power spectrum */
ps[0]=1;
for (i=1;i<N;i++)
ps[i]=1+st->frame[2*i-1]*st->frame[2*i-1] + st->frame[2*i]*st->frame[2*i];
}
/* Transform a masking curve (power spectrum) into a pole-zero filter */
void curve_to_lpc(VorbisPsy *psy, float *curve, float *awk1, float *awk2, int ord)
{
int i;
float ac[psy->n];
float tmp;
int len = psy->n >> 1;
for (i=0;i<2*len;i++)
ac[i] = 0;
for (i=1;i<len;i++)
ac[2*i-1] = curve[i];
ac[0] = curve[0];
ac[2*len-1] = curve[len-1];
spx_drft_backward(&psy->lookup, ac);
_spx_lpc(awk1, ac, ord);
tmp = 1.;
for (i=0;i<ord;i++)
{
tmp *= .99;
awk1[i] *= tmp;
}
#if 0
for (i=0;i<ord;i++)
awk2[i] = 0;
#else
/* Use the second (awk2) filter to correct the first one */
for (i=0;i<2*len;i++)
ac[i] = 0;
for (i=0;i<ord;i++)
ac[i+1] = awk1[i];
ac[0] = 1;
spx_drft_forward(&psy->lookup, ac);
/* Compute (power) response of awk1 (all zero) */
ac[0] *= ac[0];
for (i=1;i<len;i++)
ac[i] = ac[2*i-1]*ac[2*i-1] + ac[2*i]*ac[2*i];
ac[len] = ac[2*len-1]*ac[2*len-1];
/* Compute correction required */
for (i=0;i<len;i++)
curve[i] = 1. / (1e-6f+curve[i]*ac[i]);
for (i=0;i<2*len;i++)
ac[i] = 0;
for (i=1;i<len;i++)
ac[2*i-1] = curve[i];
ac[0] = curve[0];
ac[2*len-1] = curve[len-1];
spx_drft_backward(&psy->lookup, ac);
_spx_lpc(awk2, ac, ord);
tmp = 1;
for (i=0;i<ord;i++)
{
tmp *= .99;
awk2[i] *= tmp;
}
#endif
}
void compute_curve(VorbisPsy *psy, float *audio, float *curve)
{
int i;
float work[psy->n];
float scale=4.f/psy->n;
float scale_dB;
scale_dB=todB(scale);
/* window the PCM data; use a BH4 window, not vorbis */
for(i=0;i<psy->n;i++)
work[i]=audio[i] * psy->window[i];
{
static int seq=0;
//_analysis_output("win",seq,work,psy->n,0,0);
seq++;
}
/* FFT yields more accurate tonal estimation (not phase sensitive) */
spx_drft_forward(&psy->lookup,work);
/* magnitudes */
work[0]=scale_dB+todB(work[0]);
for(i=1;i<psy->n-1;i+=2){
float temp = work[i]*work[i] + work[i+1]*work[i+1];
work[(i+1)>>1] = scale_dB+.5f * todB(temp);
}
/* derive a noise curve */
_vp_noisemask(psy,work,curve);
#define SIDEL 12
for (i=0;i<SIDEL;i++)
{
curve[i]=curve[SIDEL];
}
#define SIDEH 12
for (i=0;i<SIDEH;i++)
{
curve[(psy->n>>1)-i-1]=curve[(psy->n>>1)-SIDEH];
}
for(i=0;i<((psy->n)>>1);i++)
curve[i] = fromdB(1.2*curve[i]+.2*i);
//curve[i] = fromdB(0.8*curve[i]+.35*i);
//curve[i] = fromdB(0.9*curve[i])*pow(1.0*i+45,1.3);
}
/** Performs echo cancellation on a frame */
void speex_echo_cancel(SpeexEchoState *st, short *ref, short *echo, short *out, float *Yout)
{
int i,j,m;
int N,M;
float scale;
float ESR;
float SER;
float Sry=0,Srr=0,Syy=0,Sey=0,See=0,Sxx=0;
float leak_estimate;
leak_estimate = .1+(.9/(1+2*st->sum_adapt));
N = st->window_size;
M = st->M;
scale = 1.0f/N;
st->cancel_count++;
/* Copy input data to buffer */
for (i=0; i<st->frame_size; i++)
{
st->x[i] = st->x[i+st->frame_size];
st->x[i+st->frame_size] = echo[i];
st->d[i] = st->d[i+st->frame_size];
st->d[i+st->frame_size] = ref[i];
}
/* Shift memory: this could be optimized eventually*/
for (i=0; i<N*(M-1); i++)
st->X[i]=st->X[i+N];
/* Copy new echo frame */
for (i=0; i<N; i++)
st->X[(M-1)*N+i]=st->x[i];
/* Convert x (echo input) to frequency domain */
spx_drft_forward(st->fft_lookup, &st->X[(M-1)*N]);
/* Compute filter response Y */
for (i=0; i<N; i++)
st->Y[i] = 0;
for (j=0; j<M; j++)
spectral_mul_accum(&st->X[j*N], &st->W[j*N], st->Y, N);
/* Convert Y (filter response) to time domain */
for (i=0; i<N; i++)
st->y[i] = st->Y[i];
spx_drft_backward(st->fft_lookup, st->y);
for (i=0; i<N; i++)
st->y[i] *= scale;
/* Transform d (reference signal) to frequency domain */
for (i=0; i<N; i++)
st->D[i]=st->d[i];
spx_drft_forward(st->fft_lookup, st->D);
/* Compute error signal (signal with echo removed) */
for (i=0; i<st->frame_size; i++)
{
float tmp_out;
tmp_out = (float)ref[i] - st->y[i+st->frame_size];
st->E[i] = 0;
st->E[i+st->frame_size] = tmp_out;
/* Saturation */
if (tmp_out>32767)
tmp_out = 32767;
else if (tmp_out<-32768)
tmp_out = -32768;
out[i] = tmp_out;
}
/* This bit of code provides faster adaptation by doing a projection of the previous gradient on the
"MMSE surface" */
if (1)
{
float Sge, Sgg, Syy;
float gain;
Syy = inner_prod(st->y+st->frame_size, st->y+st->frame_size, st->frame_size);
for (i=0; i<N; i++)
st->Y2[i] = 0;
for (j=0; j<M; j++)
spectral_mul_accum(&st->X[j*N], &st->PHI[j*N], st->Y2, N);
for (i=0; i<N; i++)
st->y2[i] = st->Y2[i];
spx_drft_backward(st->fft_lookup, st->y2);
for (i=0; i<N; i++)
st->y2[i] *= scale;
Sge = inner_prod(st->y2+st->frame_size, st->E+st->frame_size, st->frame_size);
Sgg = inner_prod(st->y2+st->frame_size, st->y2+st->frame_size, st->frame_size);
/* Compute projection gain */
gain = Sge/(N+.03*Syy+Sgg);
if (gain>2)
gain = 2;
if (gain < -2)
gain = -2;
/* Apply gain to weights, echo estimates, output */
for (i=0; i<N; i++)
st->Y[i] += gain*st->Y2[i];
for (i=0; i<st->frame_size; i++)
{
st->y[i+st->frame_size] += gain*st->y2[i+st->frame_size];
st->E[i+st->frame_size] -= gain*st->y2[i+st->frame_size];
}
for (i=0; i<M*N; i++)
st->W[i] += gain*st->PHI[i];
}
/* Compute power spectrum of output (D-Y) and filter response (Y) */
for (i=0; i<N; i++)
st->D[i] -= st->Y[i];
power_spectrum(st->D, st->Rf, N);
power_spectrum(st->Y, st->Yf, N);
/* Compute frequency-domain adaptation mask */
for (j=0; j<=st->frame_size; j++)
{
float r;
r = leak_estimate*st->Yf[j] / (1+st->Rf[j]);
if (r>1)
r = 1;
st->fratio[j] = r;
}
/* Compute a bunch of correlations */
Sry = inner_prod(st->y+st->frame_size, st->d+st->frame_size, st->frame_size);
Sey = inner_prod(st->y+st->frame_size, st->E+st->frame_size, st->frame_size);
See = inner_prod(st->E+st->frame_size, st->E+st->frame_size, st->frame_size);
Syy = inner_prod(st->y+st->frame_size, st->y+st->frame_size, st->frame_size);
Srr = inner_prod(st->d+st->frame_size, st->d+st->frame_size, st->frame_size);
Sxx = inner_prod(st->x+st->frame_size, st->x+st->frame_size, st->frame_size);
/* Compute smoothed cross-correlation and energy */
st->Sey = .98*st->Sey + .02*Sey;
st->Syy = .98*st->Syy + .02*Syy;
st->See = .98*st->See + .02*See;
/* Check if filter is completely mis-adapted (if so, reset filter) */
if (st->Sey/(1+st->Syy + .01*st->See) < -1)
{
/*fprintf (stderr, "reset at %d\n", st->cancel_count);*/
speex_echo_state_reset(st);
return;
}
SER = Srr / (1+Sxx);
ESR = leak_estimate*Syy / (1+See);
if (ESR>1)
ESR = 1;
#if 1
/* If over-cancellation (creating echo with 180 phase) damp filter */
if (st->Sey/(1+st->Syy) < -.1 && (ESR > .3))
{
for (i=0; i<M*N; i++)
st->W[i] *= .95;
st->Sey *= .5;
/*fprintf (stderr, "corrected down\n");*/
}
#endif
#if 1
/* If under-cancellation (leaving echo with 0 phase) scale filter up */
if (st->Sey/(1+st->Syy) > .1 && (ESR > .1 || SER < 10))
{
for (i=0; i<M*N; i++)
st->W[i] *= 1.05;
st->Sey *= .5;
/*fprintf (stderr, "corrected up %d\n", st->cancel_count);*/
}
#endif
/* We consider that the filter is adapted if the following is true*/
if (ESR>.6 && st->sum_adapt > 1)
{
/*if (!st->adapted)
fprintf(stderr, "Adapted at %d %f\n", st->cancel_count, st->sum_adapt);*/
st->adapted = 1;
}
/* Update frequency-dependent energy ratio with the total energy ratio */
for (i=0; i<=st->frame_size; i++)
{
st->fratio[i] = (.2*ESR+.8*min(.005+ESR,st->fratio[i]));
}
if (st->adapted)
{
st->adapt_rate = .95f/(2+M);
} else {
/* Temporary adaption rate if filter is not adapted correctly */
if (SER<.1)
st->adapt_rate =.8/(2+M);
else if (SER<1)
st->adapt_rate =.4/(2+M);
else if (SER<10)
st->adapt_rate =.2/(2+M);
else if (SER<30)
st->adapt_rate =.08/(2+M);
else
st->adapt_rate = 0;
}
/* How much have we adapted so far? */
st->sum_adapt += st->adapt_rate;
/* Compute echo power in each frequency bin */
{
float ss = 1.0f/st->cancel_count;
if (ss < .3/M)
ss=.3/M;
power_spectrum(&st->X[(M-1)*N], st->Xf, N);
/* Smooth echo energy estimate over time */
for (j=0; j<=st->frame_size; j++)
st->power[j] = (1-ss)*st->power[j] + ss*st->Xf[j];
/* Combine adaptation rate to the the inverse energy estimate */
if (st->adapted)
{
/* If filter is adapted, include the frequency-dependent ratio too */
for (i=0; i<=st->frame_size; i++)
st->power_1[i] = st->adapt_rate*st->fratio[i] /(1.f+st->power[i]);
} else {
for (i=0; i<=st->frame_size; i++)
st->power_1[i] = st->adapt_rate/(1.f+st->power[i]);
}
}
/* Convert error to frequency domain */
spx_drft_forward(st->fft_lookup, st->E);
/* Do some regularization (prevents problems when system is ill-conditoned) */
for (m=0; m<M; m++)
for (i=0; i<N; i++)
st->W[m*N+i] *= 1-st->regul[i]*ESR;
/* Compute weight gradient */
for (j=0; j<M; j++)
{
weighted_spectral_mul_conj(st->power_1, &st->X[j*N], st->E, st->PHI+N*j, N);
}
/* Gradient descent */
for (i=0; i<M*N; i++)
st->W[i] += st->PHI[i];
/* AUMDF weight constraint */
for (j=0; j<M; j++)
{
/* Remove the "if" to make this an MDF filter */
if (st->cancel_count%M == j)
{
spx_drft_backward(st->fft_lookup, &st->W[j*N]);
for (i=0; i<N; i++)
st->W[j*N+i]*=scale;
for (i=st->frame_size; i<N; i++)
{
st->W[j*N+i]=0;
}
spx_drft_forward(st->fft_lookup, &st->W[j*N]);
}
}
/* Compute spectrum of estimated echo for use in an echo post-filter (if necessary)*/
if (Yout)
{
if (st->adapted)
{
/* If the filter is adapted, take the filtered echo */
for (i=0; i<st->frame_size; i++)
st->last_y[i] = st->last_y[st->frame_size+i];
for (i=0; i<st->frame_size; i++)
st->last_y[st->frame_size+i] = st->y[st->frame_size+i];
} else {
/* If filter isn't adapted yet, all we can do is take the echo signal directly */
for (i=0; i<N; i++)
st->last_y[i] = st->x[i];
}
/* Apply hanning window (should pre-compute it)*/
for (i=0; i<N; i++)
st->Yps[i] = (.5-.5*cos(2*M_PI*i/N))*st->last_y[i];
/* Compute power spectrum of the echo */
spx_drft_forward(st->fft_lookup, st->Yps);
power_spectrum(st->Yps, st->Yps, N);
/* Estimate residual echo */
for (i=0; i<=st->frame_size; i++)
Yout[i] = 2*leak_estimate*st->Yps[i];
}
}
