Include vamp-pyin

In preparation for captainMorgan's pitch analysis script.

libs/vamp-pyin/MeanFilter.h

@@ -0,0 +1,63 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    pYIN - A fundamental frequency estimator for monophonic audio
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _MEAN_FILTER_H_
+#define _MEAN_FILTER_H_
+
+class MeanFilter
+{
+public:
+    /**
+     * Construct a non-causal mean filter with filter length flen,
+     * that replaces each sample N with the mean of samples
+     * [N-floor(F/2) .. N+floor(F/2)] where F is the filter length.
+     * Only odd F are supported.
+     */
+    MeanFilter(int flen) : m_flen(flen) { }
+    ~MeanFilter() { }
+
+    /**
+     * Filter the n samples in "in" and place the results in "out"
+     */
+    void filter(const double *in, double *out, const int n) {
+	filterSubsequence(in, out, n, n, 0);
+    }
+
+    /**
+     * Filter the n samples starting at the given offset in the
+     * m-element array "in" and place the results in the n-element
+     * array "out"
+     */
+    void filterSubsequence(const double *in, double *out,
+			   const int m, const int n,
+			   const int offset) {
+	int half = m_flen/2;
+	for (int i = 0; i < n; ++i) {
+	    double v = 0;
+	    int n = 0;
+	    for (int j = -half; j <= half; ++j) {
+		int ix = i + j + offset;
+		if (ix >= 0 && ix < m) {
+		    v += in[ix];
+		    ++n;
+		}
+	    }
+	    out[i] = v / n;
+	}
+    }
+
+private:
+    int m_flen;
+};
+
+#endif