Added pitch analysis. Doesn't crash, but otherwise untested.

1 files changed, 77 insertions, 0 deletions

diff --git a/libcelt/pitch.c b/libcelt/pitch.c
new file mode 100644
index 0000000..53a6d86
--- /dev/null
+++ b/libcelt/pitch.c
@@ -0,0 +1,77 @@
+/**
+   @file pitch.c
+   @brief Pitch analysis
+*/
+
+/* Copyright (C) 2005
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+
+#include <stdio.h>
+#include <math.h>
+#include "fftwrap.h"
+
+
+void find_spectral_pitch(float *x, float *y, int lag, int len, int *pitch, float *curve)
+{
+   //FIXME: Yuck!!!
+   static void *fft;
+   
+   if (!fft)
+      fft = spx_fft_init(lag);
+   
+   float xx[lag];
+   float X[lag];
+   float Y[lag];
+   int i;
+   
+   for (i=0;i<lag;i++)
+      xx[i] = 0;
+   for (i=0;i<len;i++)
+      xx[i] = x[i];
+   
+   spx_fft(fft, xx, X);
+   spx_fft(fft, y, Y);
+   X[0] = X[0]*Y[0];
+   for (i=1;i<lag/2;i++)
+   {
+      float n = 1.f/(1e1+sqrt((X[2*i-1]*X[2*i-1] + X[2*i  ]*X[2*i  ])*(Y[2*i-1]*Y[2*i-1] + Y[2*i  ]*Y[2*i  ])));
+      //n = 1;
+      //n = 1.f/(1+curve[i]);
+      
+      float tmp = X[2*i-1];
+      X[2*i-1] = (X[2*i-1]*Y[2*i-1] + X[2*i  ]*Y[2*i  ])*n;
+      X[2*i  ] = (- X[2*i  ]*Y[2*i-1] + tmp*Y[2*i  ])*n;
+   }
+   X[len-1] = 0;
+   X[0] = X[len-1] = 0;
+   spx_ifft(fft, X, xx);
+   
+   float max_corr=-1;
+   //int pitch;
+   *pitch = -1;
+   for (i=0;i<lag-len;i++)
+   {
+      //printf ("%f ", xx[i]);
+      if (xx[i] > max_corr)
+      {
+         *pitch = i;
+         max_corr = xx[i];
+      }
+   }
+   //printf ("%d\n", *pitch);
+}