int main()
{
int n, ip[NMAXSQRT + 2];
double a[NMAX + 1], w[NMAX * 5 / 4], t[NMAX / 2 + 1], err;
printf("data length n=? (must be 2^m)\n");
scanf("%d", &n);
ip[0] = 0;
/* check of CDFT */
putdata(0, n - 1, a);
cdft(n, 1, a, ip, w);
cdft(n, -1, a, ip, w);
err = errorcheck(0, n - 1, 2.0 / n, a);
printf("cdft err= %g \n", err);
/* check of RDFT */
putdata(0, n - 1, a);
rdft(n, 1, a, ip, w);
rdft(n, -1, a, ip, w);
err = errorcheck(0, n - 1, 2.0 / n, a);
printf("rdft err= %g \n", err);
/* check of DDCT */
putdata(0, n - 1, a);
ddct(n, 1, a, ip, w);
ddct(n, -1, a, ip, w);
a[0] *= 0.5;
err = errorcheck(0, n - 1, 2.0 / n, a);
printf("ddct err= %g \n", err);
/* check of DDST */
putdata(0, n - 1, a);
ddst(n, 1, a, ip, w);
ddst(n, -1, a, ip, w);
a[0] *= 0.5;
err = errorcheck(0, n - 1, 2.0 / n, a);
printf("ddst err= %g \n", err);
/* check of DFCT */
putdata(0, n, a);
a[0] *= 0.5;
a[n] *= 0.5;
dfct(n, a, t, ip, w);
a[0] *= 0.5;
a[n] *= 0.5;
dfct(n, a, t, ip, w);
err = errorcheck(0, n, 2.0 / n, a);
printf("dfct err= %g \n", err);
/* check of DFST */
putdata(1, n - 1, a);
dfst(n, a, t, ip, w);
dfst(n, a, t, ip, w);
err = errorcheck(1, n - 1, 2.0 / n, a);
printf("dfst err= %g \n", err);
return 0;
}
void dfct(int n, double *a)
{
void ddct(int n, int isgn, double *a);
void bitrv1(int n, double *a);
int j, k, m, mh;
double xr, xi, yr, yi, an;
m = n >> 1;
for (j = 0; j < m; j++) {
k = n - j;
xr = a[j] + a[k];
a[j] -= a[k];
a[k] = xr;
}
an = a[n];
while (m >= 2) {
ddct(m, 1, a);
bitrv1(m, a);
mh = m >> 1;
xi = a[m];
a[m] = a[0];
a[0] = an - xi;
an += xi;
for (j = 1; j < mh; j++) {
k = m - j;
xr = a[m + k];
xi = a[m + j];
yr = a[j];
yi = a[k];
a[m + j] = yr;
a[m + k] = yi;
a[j] = xr - xi;
a[k] = xr + xi;
}
xr = a[mh];
a[mh] = a[m + mh];
a[m + mh] = xr;
m = mh;
}
xi = a[1];
a[1] = a[0];
a[0] = an + xi;
a[n] = an - xi;
bitrv1(n, a);
}
void chebexp(double (*f)(T), T a, T b, T eps,
BasicArray<T> &c, T &err)
{
int lenc = c.n() ;
int j, k, l, n;
T esf, ba, cos2, sin2, wi, ss, x, y, t, h, eref, erefh, errh;
esf = 10;
ba = T(0.5) * (b - a);
c[0] = T(0.5) * (*f)(a);
c[2] = T(0.5) * (*f)(b);
c[1] = (*f)(a + ba);
c[lenc - 1] = c[0] - c[2];
c[lenc] = c[0] + c[2] + c[1];
c[lenc - 2] = c[0] + c[2] - c[1];
cos2 = 0;
sin2 = 1;
wi = -1;
h = 1;
l = 1;
n = 2;
eref = erefh = T() ;
do {
ss = 2 * sin2;
cos2 = sqrt(2 + cos2);
sin2 /= 2 + cos2;
x = ba * sin2;
y = 0;
for (j = 0; j <= l - 1; j++) {
x += y;
y += ss * (ba - x);
c[j] = (*f)(a + x);
c[n - 1 - j] = (*f)(b - x);
}
wi /= cos2;
ddct(n, T(0.5) * cos2, wi, c);
l = n;
n *= 2;
for (j = l - 1; j >= 0; j--) {
k = lenc - j;
t = c[k] - c[j];
c[k] += c[j];
c[lenc - n + j] = t;
}
if (n == 4) {
eref = T(0.25) * (fabs(c[lenc]) + fabs(c[lenc - 1]) +
fabs(c[lenc - 2]) + fabs(c[lenc - 3]) + fabs(c[lenc - 4]));
erefh = eref * sqrt(eps);
eref *= eps;
err = erefh;
}
h *= T(0.5);
errh = esf * err;
err = h * (T(0.5) * fabs(c[lenc - n]) + fabs(c[lenc - n + 1]));
} while ((err > eref || errh > erefh) && 2 * n + 4 <= lenc);
c[lenc - n] *= T(0.5);
c[lenc] *= T(0.5);
for (j = lenc - n; j <= lenc; j++) {
c[j] *= h;
}
if (err > eref || errh > erefh) {
err = -(err);
} else {
do {
n -= 2;
err += fabs(c[lenc - n]) + fabs(c[lenc - n + 1]);
} while (err < eref && n > 2);
n += 2;
err = eref;
}
if (ba != 0) {
c[3] = 1 / ba;
} else {
c[3] = 0;
}
c[2] = T(0.5) * (b + a);
c[1] = n + T(0.5);
c[0] = lenc + T(0.5);
}
void
whs_extractor_process (WhsExtractor *self, const gfloat *in, WhsFeatureVector *ret)
{
gdouble tmp;
// Calculate MFCC
// http://de.wikipedia.org/wiki/MFCC
// Copy to our temporary array and apply hamming window
gdouble *freqdata = self->priv->fft.freqdata;
for (gint i = 0; i < self->frame_length; i++) {
freqdata[i] = in[i] * self->priv->cos[i];
}
// Take FFT
rdft (self->frame_length, 1, freqdata, self->priv->fft.ip, self->priv->fft.w);
// Store magnitude spectrum in freqdata[0...n/2]
for (guint i = 0; i < self->frame_length; i += 2) {
gdouble cur;
if (i == 0) {
freqdata[0] = freqdata[0] * freqdata[0];
freqdata[1] = freqdata[1] * freqdata[1];
} else {
cur = freqdata[i / 2 + 1] = freqdata[i] * freqdata[i] + freqdata[i+1] * freqdata[i+1];
}
}
// Move freqdata[1] to the end, it's for the nyquist frequency!
tmp = freqdata[1];
g_memmove (&freqdata[1], &freqdata[2], sizeof (gdouble) * (self->frame_length / 2 - 1));
freqdata[self->frame_length / 2] = tmp;
// Take logarithms
for (gint i = 0; i < self->frame_length / 2 + 1; i++) {
if (freqdata[i] != 0.0)
freqdata[i] = CLAMP (log10 (sqrt (freqdata[i]/(self->frame_length*self->frame_length))), -500.0, G_MAXDOUBLE);
else
freqdata[i] = -500.0;
}
// Convert to mel spectrum
gdouble bins[32];
#if 0
{
gint bin = 0;
gint step = mel (self->sample_rate / 2) / 32; // 32 bins
for (bin = 0; bin < 32; bin++) {
gint i;
bins[bin] = 0.0;
// Fill bin from 'start' to 'stop' with triangular weighting
gdouble start = (bin > 0) ? bin * step - 0.5 * step : 0;
gdouble stop = (bin < 31) ? (bin + 1) * step + 0.5 * step : (bin + 1) * step;
for (i = 0; i < self->frame_length / 2 + 1; i++) {
gdouble f = (((gfloat) i) / ((gfloat) (self->frame_length))) * self->sample_rate;
bins[bin] += triangle (start, stop, mel (f)) * freqdata[i];
}
}
}
#else
{
#if 1
gint i, j = 0, bin = 0;
gint start_m = (self->min_freq > 0) ? mel (CLAMP (self->min_freq - (self->sample_rate / self->frame_length), 0, self->sample_rate / 2)) : 0;
gint stop_m = (self->max_freq > 0) ? mel (CLAMP (self->max_freq + (self->sample_rate / self->frame_length), 0, self->sample_rate / 2)) : mel (self->sample_rate / 2);
gint step = (stop_m - start_m) / 32; // 32 bins
#else
gint i, j = 0, bin = 0;
gint start_m = 0;
gint step = mel (self->sample_rate / 2) / 32; // 32 bins
#endif
for (bin = i = 0; bin < 32; bin++, i += j) {
bins[bin] = 0.0;
// Fill bin
for (j = 0; (i + j) <= self->frame_length / 2 && mel (((i + j) * (self->sample_rate / 2)) / (self->frame_length / 2)) <= start_m + step * (bin + 1); j++) {
bins[bin] += freqdata[i+j];
}
// Normalize bin
if (j != 0)
bins[bin] /= j;
}
}
#endif
// Calculate DCT
ddct (32, -1, bins, self->priv->dct.ip, self->priv->dct.w);
for (gint i = 0; i < 32; i++)
ret->mfcc[i] = bins[i];
}
