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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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+////////////////////////////////////////////////////////////////////////////////
+///
+/// Sample interpolation routine using 8-tap band-limited Shannon interpolation
+/// with kaiser window.
+///
+/// Notice. This algorithm is remarkably much heavier than linear or cubic
+/// interpolation, and not remarkably better than cubic algorithm. Thus mostly
+/// for experimental purposes
+///
+/// Author : Copyright (c) Olli Parviainen
+/// Author e-mail : oparviai 'at' iki.fi
+/// SoundTouch WWW: http://www.surina.net/soundtouch
+///
+////////////////////////////////////////////////////////////////////////////////
+//
+// $Id: InterpolateShannon.cpp 195 2014-04-06 15:57:21Z oparviai $
+//
+////////////////////////////////////////////////////////////////////////////////
+//
+// License :
+//
+// SoundTouch audio processing library
+// Copyright (c) Olli Parviainen
+//
+// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <math.h>
+#include "InterpolateShannon.h"
+#include "STTypes.h"
+
+using namespace soundtouch;
+
+
+/// Kaiser window with beta = 2.0
+/// Values scaled down by 5% to avoid overflows
+static const double _kaiser8[8] =
+{
+ 0.41778693317814,
+ 0.64888025049173,
+ 0.83508562409944,
+ 0.93887857733412,
+ 0.93887857733412,
+ 0.83508562409944,
+ 0.64888025049173,
+ 0.41778693317814
+};
+
+
+InterpolateShannon::InterpolateShannon()
+{
+ fract = 0;
+}
+
+
+void InterpolateShannon::resetRegisters()
+{
+ fract = 0;
+}
+
+
+#define PI 3.1415926536
+#define sinc(x) (sin(PI * (x)) / (PI * (x)))
+
+/// Transpose mono audio. Returns number of produced output samples, and
+/// updates "srcSamples" to amount of consumed source samples
+int InterpolateShannon::transposeMono(SAMPLETYPE *pdest,
+ const SAMPLETYPE *psrc,
+ int &srcSamples)
+{
+ int i;
+ int srcSampleEnd = srcSamples - 8;
+ int srcCount = 0;
+
+ i = 0;
+ while (srcCount < srcSampleEnd)
+ {
+ double out;
+ assert(fract < 1.0);
+
+ out = psrc[0] * sinc(-3.0 - fract) * _kaiser8[0];
+ out += psrc[1] * sinc(-2.0 - fract) * _kaiser8[1];
+ out += psrc[2] * sinc(-1.0 - fract) * _kaiser8[2];
+ if (fract < 1e-6)
+ {
+ out += psrc[3] * _kaiser8[3]; // sinc(0) = 1
+ }
+ else
+ {
+ out += psrc[3] * sinc(- fract) * _kaiser8[3];
+ }
+ out += psrc[4] * sinc( 1.0 - fract) * _kaiser8[4];
+ out += psrc[5] * sinc( 2.0 - fract) * _kaiser8[5];
+ out += psrc[6] * sinc( 3.0 - fract) * _kaiser8[6];
+ out += psrc[7] * sinc( 4.0 - fract) * _kaiser8[7];
+
+ pdest[i] = (SAMPLETYPE)out;
+ i ++;
+
+ // update position fraction
+ fract += rate;
+ // update whole positions
+ int whole = (int)fract;
+ fract -= whole;
+ psrc += whole;
+ srcCount += whole;
+ }
+ srcSamples = srcCount;
+ return i;
+}
+
+
+/// Transpose stereo audio. Returns number of produced output samples, and
+/// updates "srcSamples" to amount of consumed source samples
+int InterpolateShannon::transposeStereo(SAMPLETYPE *pdest,
+ const SAMPLETYPE *psrc,
+ int &srcSamples)
+{
+ int i;
+ int srcSampleEnd = srcSamples - 8;
+ int srcCount = 0;
+
+ i = 0;
+ while (srcCount < srcSampleEnd)
+ {
+ double out0, out1, w;
+ assert(fract < 1.0);
+
+ w = sinc(-3.0 - fract) * _kaiser8[0];
+ out0 = psrc[0] * w; out1 = psrc[1] * w;
+ w = sinc(-2.0 - fract) * _kaiser8[1];
+ out0 += psrc[2] * w; out1 += psrc[3] * w;
+ w = sinc(-1.0 - fract) * _kaiser8[2];
+ out0 += psrc[4] * w; out1 += psrc[5] * w;
+ w = _kaiser8[3] * ((fract < 1e-5) ? 1.0 : sinc(- fract)); // sinc(0) = 1
+ out0 += psrc[6] * w; out1 += psrc[7] * w;
+ w = sinc( 1.0 - fract) * _kaiser8[4];
+ out0 += psrc[8] * w; out1 += psrc[9] * w;
+ w = sinc( 2.0 - fract) * _kaiser8[5];
+ out0 += psrc[10] * w; out1 += psrc[11] * w;
+ w = sinc( 3.0 - fract) * _kaiser8[6];
+ out0 += psrc[12] * w; out1 += psrc[13] * w;
+ w = sinc( 4.0 - fract) * _kaiser8[7];
+ out0 += psrc[14] * w; out1 += psrc[15] * w;
+
+ pdest[2*i] = (SAMPLETYPE)out0;
+ pdest[2*i+1] = (SAMPLETYPE)out1;
+ i ++;
+
+ // update position fraction
+ fract += rate;
+ // update whole positions
+ int whole = (int)fract;
+ fract -= whole;
+ psrc += 2*whole;
+ srcCount += whole;
+ }
+ srcSamples = srcCount;
+ return i;
+}
+
+
+/// Transpose stereo audio. Returns number of produced output samples, and
+/// updates "srcSamples" to amount of consumed source samples
+int InterpolateShannon::transposeMulti(SAMPLETYPE *pdest,
+ const SAMPLETYPE *psrc,
+ int &srcSamples)
+{
+ // not implemented
+ assert(false);
+ return 0;
+}