Add in tree aubio

Signed-off-by: falkTX <falktx@falktx.com>

deps/aubio/src/temporal/biquad.h

@@ -0,0 +1,75 @@
+/*
+  Copyright (C) 2003-2015 Paul Brossier <piem@aubio.org>
+
+  This file is part of aubio.
+
+  aubio 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 3 of the License, or
+  (at your option) any later version.
+
+  aubio 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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with aubio.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#ifndef AUBIO_FILTER_BIQUAD_H
+#define AUBIO_FILTER_BIQUAD_H
+
+/** \file
+
+  Second order Infinite Impulse Response filter
+
+  This file implements a normalised biquad filter (second order IIR):
+
+  \f$ y[n] = b_0 x[n] + b_1 x[n-1] + b_2 x[n-2] - a_1 y[n-1] - a_2 y[n-2] \f$
+
+  The filtfilt version runs the filter twice, forward and backward, to
+  compensate the phase shifting of the forward operation.
+
+  See also <a href="http://en.wikipedia.org/wiki/Digital_biquad_filter">Digital
+  biquad filter</a> on wikipedia.
+
+  \example temporal/test-biquad.c
+
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** set coefficients of a biquad filter
+
+  \param f filter object as returned by new_aubio_filter()
+  \param b0 forward filter coefficient
+  \param b1 forward filter coefficient
+  \param b2 forward filter coefficient
+  \param a1 feedback filter coefficient
+  \param a2 feedback filter coefficient
+
+*/
+uint_t aubio_filter_set_biquad (aubio_filter_t * f, lsmp_t b0, lsmp_t b1,
+    lsmp_t b2, lsmp_t a1, lsmp_t a2);
+
+/** create biquad filter with `b0`, `b1`, `b2`, `a1`, `a2` coeffs
+
+  \param b0 forward filter coefficient
+  \param b1 forward filter coefficient
+  \param b2 forward filter coefficient
+  \param a1 feedback filter coefficient
+  \param a2 feedback filter coefficient
+
+*/
+aubio_filter_t *new_aubio_filter_biquad (lsmp_t b0, lsmp_t b1, lsmp_t b2,
+    lsmp_t a1, lsmp_t a2);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AUBIO_FILTER_BIQUAD_H */