Changes in / [f98063b:5bdbb83]

File:

• src/pitch/pitchyinfft.c (modified) (5 diffs)

src/pitch/pitchyinfft.c

@@ -38 +38 @@
   smpl_t tol;         /**< Yin tolerance */
   smpl_t confidence;  /**< confidence */
-  uint_t short_period; /** shortest period under which to check for octave error */
+  uint_t samplerate;  /**< samplerate we got initialized with */
 };
 
@@ -70 +70 @@
   p->win = new_aubio_window ("hanningz", bufsize);
   p->weight = new_fvec (bufsize / 2 + 1);
+  p->samplerate = samplerate;
   for (i = 0; i < p->weight->length; i++) {
     freq = (smpl_t) i / (smpl_t) bufsize *(smpl_t) samplerate;
@@ -94 +95 @@
     //p->weight->data[i] = SQRT(DB2LIN(p->weight->data[i]));
   }
-  // check for octave errors above 1300 Hz
-  p->short_period = (uint_t)ROUND(samplerate / 1300.);
+
+  // disable weighting
+  fvec_set_all (p->weight, 1.0);
+
   return p;
 
@@ -109 +112 @@
   uint_t tau, l;
   uint_t length = p->fftout->length;
-  uint_t halfperiod;
   fvec_t *fftout = p->fftout;
   fvec_t *yin = p->yinfft;
   smpl_t tmp = 0., sum = 0.;
+  // empirically derived peak width to look for
+  uint_t lookafter = yin->length / 128, endbin;
+
   // window the input
   fvec_weighted_copy(input, p->win, p->winput);
@@ -146 +151 @@
     }
   }
-  // find best candidates
-  tau = fvec_min_elem (yin);
-  if (yin->data[tau] < p->tol) {
-    // no interpolation, directly return the period as an integer
-    //output->data[0] = tau;
-    //return;
-
-    // 3 point quadratic interpolation
-    //return fvec_quadratic_peak_pos (yin,tau,1);
-    /* additional check for (unlikely) octave doubling in higher frequencies */
-    if (tau > p->short_period) {
-      output->data[0] = fvec_quadratic_peak_pos (yin, tau);
-    } else {
-      /* should compare the minimum value of each interpolated peaks */
-      halfperiod = FLOOR (tau / 2 + .5);
-      if (yin->data[halfperiod] < p->tol)
-        output->data[0] = fvec_quadratic_peak_pos (yin, halfperiod);
-      else
-        output->data[0] = fvec_quadratic_peak_pos (yin, tau);
-    }
-  } else {
+
+  // calc min available confidence first
+  tmp = fvec_min(yin);
+  if (tmp > p->tol) {
+    // give up - got no confident candidate at all
     output->data[0] = 0.;
-  }
+    return;
+  }
+
+  // choose first confident candidate, to avoid choosing lower harmonics
+  tau = 0;
+  for (l = 1; l < yin->length; l++) {
+    // is this candidate "roughly" as good as the lowest one?
+    // the constant 0.1 is empirically derived
+    if (ABS (yin->data[l] - tmp) < 0.1) {
+      tau = l;
+      break;
+    }
+  }
+  // find local min around current peak to sharpen the results
+  endbin = tau + lookafter < yin->length - 1 ? tau + lookafter : yin->length - 1;
+  tmp = yin->data[tau];
+  for (l = tau; l < endbin; l++) {
+    if (yin->data[l] < tmp ) {
+      tmp = yin->data[l];
+      tau = l;
+    }
+    // stop as soon as we start going up again
+    if (yin->data[l] > tmp && l > tau) {
+      break;
+    }
+  }
+  output->data[0] = fvec_quadratic_peak_pos(yin, tau);
 }