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+/*
+  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_C_DESIGN_H
+#define AUBIO_FILTER_C_DESIGN_H
+
+/** \file
+
+  C-weighting filter coefficients
+
+  This file creates a C-weighting digital filter, which reduces low and high
+  frequencies and enhance the middle ones to reflect the ability of the human
+  hearing.
+
+  The implementation is based on the following standard:
+
+    - IEC/CD 1672: Electroacoustics-Sound Level Meters, IEC, Geneva, Nov.  1996,
+  for A- and C-weighting filters.
+
+  See also:
+
+    - <a href="http://en.wikipedia.org/wiki/A-weighting">A-Weighting on
+  Wikipedia</a>
+    - <a href="http://en.wikipedia.org/wiki/Weighting_filter">Weighting filter on
+  Wikipedia</a>
+    - <a href="http://www.mathworks.com/matlabcentral/fileexchange/69">Christophe
+  Couvreur's 'octave' toolbox</a>
+
+  The coefficients in this file have been computed using Christophe Couvreur's
+  scripts in octave 3.0 (debian package 1:3.0.5-6+b2 with octave-signal
+  1.0.9-1+b1 on i386), with <pre> [b, a] = cdsign(1/Fs) </pre> for various
+  sampling frequencies (8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000,
+  88200, 96000, and 192000 Hz).
+
+  The sampling frequency should normally be higher than 20kHz, but most common
+  file sampling rates have been included for completeness.
+
+  \example temporal/test-c_weighting.c
+
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** create new C-design filter
+
+  \param samplerate sampling frequency of the signal to filter. Should be one of
+  8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and
+  192000 Hz
+
+  \return a new filter object
+
+*/
+aubio_filter_t *new_aubio_filter_c_weighting (uint_t samplerate);
+
+/** set feedback and feedforward coefficients of a C-weighting filter
+
+  \param f filter object to get coefficients from
+  \param samplerate sampling frequency of the signal to filter. Should be one of
+  8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and
+  192000 Hz
+
+*/
+uint_t aubio_filter_set_c_weighting (aubio_filter_t * f, uint_t samplerate);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AUBIO_FILTER_C_DESIGN_H */