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Diffstat (limited to 'media/libsoundtouch/src/InterpolateCubic.cpp')
| -rw-r--r-- | media/libsoundtouch/src/InterpolateCubic.cpp | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/media/libsoundtouch/src/InterpolateCubic.cpp b/media/libsoundtouch/src/InterpolateCubic.cpp new file mode 100644 index 0000000000..b37b0fa801 --- /dev/null +++ b/media/libsoundtouch/src/InterpolateCubic.cpp @@ -0,0 +1,196 @@ +//////////////////////////////////////////////////////////////////////////////// +/// +/// Cubic interpolation routine. +/// +/// Author : Copyright (c) Olli Parviainen +/// Author e-mail : oparviai 'at' iki.fi +/// SoundTouch WWW: http://www.surina.net/soundtouch +/// +//////////////////////////////////////////////////////////////////////////////// +// +// 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 <stddef.h> +#include <math.h> +#include "InterpolateCubic.h" +#include "STTypes.h" + +using namespace soundtouch; + +// cubic interpolation coefficients +static const float _coeffs[]= +{ -0.5f, 1.0f, -0.5f, 0.0f, + 1.5f, -2.5f, 0.0f, 1.0f, + -1.5f, 2.0f, 0.5f, 0.0f, + 0.5f, -0.5f, 0.0f, 0.0f}; + + +InterpolateCubic::InterpolateCubic() +{ + fract = 0; +} + + +void InterpolateCubic::resetRegisters() +{ + fract = 0; +} + + +/// Transpose mono audio. Returns number of produced output samples, and +/// updates "srcSamples" to amount of consumed source samples +int InterpolateCubic::transposeMono(SAMPLETYPE *pdest, + const SAMPLETYPE *psrc, + int &srcSamples) +{ + int i; + int srcSampleEnd = srcSamples - 4; + int srcCount = 0; + + i = 0; + while (srcCount < srcSampleEnd) + { + float out; + const float x3 = 1.0f; + const float x2 = (float)fract; // x + const float x1 = x2*x2; // x^2 + const float x0 = x1*x2; // x^3 + float y0, y1, y2, y3; + + assert(fract < 1.0); + + y0 = _coeffs[0] * x0 + _coeffs[1] * x1 + _coeffs[2] * x2 + _coeffs[3] * x3; + y1 = _coeffs[4] * x0 + _coeffs[5] * x1 + _coeffs[6] * x2 + _coeffs[7] * x3; + y2 = _coeffs[8] * x0 + _coeffs[9] * x1 + _coeffs[10] * x2 + _coeffs[11] * x3; + y3 = _coeffs[12] * x0 + _coeffs[13] * x1 + _coeffs[14] * x2 + _coeffs[15] * x3; + + out = y0 * psrc[0] + y1 * psrc[1] + y2 * psrc[2] + y3 * psrc[3]; + + 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 InterpolateCubic::transposeStereo(SAMPLETYPE *pdest, + const SAMPLETYPE *psrc, + int &srcSamples) +{ + int i; + int srcSampleEnd = srcSamples - 4; + int srcCount = 0; + + i = 0; + while (srcCount < srcSampleEnd) + { + const float x3 = 1.0f; + const float x2 = (float)fract; // x + const float x1 = x2*x2; // x^2 + const float x0 = x1*x2; // x^3 + float y0, y1, y2, y3; + float out0, out1; + + assert(fract < 1.0); + + y0 = _coeffs[0] * x0 + _coeffs[1] * x1 + _coeffs[2] * x2 + _coeffs[3] * x3; + y1 = _coeffs[4] * x0 + _coeffs[5] * x1 + _coeffs[6] * x2 + _coeffs[7] * x3; + y2 = _coeffs[8] * x0 + _coeffs[9] * x1 + _coeffs[10] * x2 + _coeffs[11] * x3; + y3 = _coeffs[12] * x0 + _coeffs[13] * x1 + _coeffs[14] * x2 + _coeffs[15] * x3; + + out0 = y0 * psrc[0] + y1 * psrc[2] + y2 * psrc[4] + y3 * psrc[6]; + out1 = y0 * psrc[1] + y1 * psrc[3] + y2 * psrc[5] + y3 * psrc[7]; + + 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 multi-channel audio. Returns number of produced output samples, and +/// updates "srcSamples" to amount of consumed source samples +int InterpolateCubic::transposeMulti(SAMPLETYPE *pdest, + const SAMPLETYPE *psrc, + int &srcSamples) +{ + int i; + int srcSampleEnd = srcSamples - 4; + int srcCount = 0; + + i = 0; + while (srcCount < srcSampleEnd) + { + const float x3 = 1.0f; + const float x2 = (float)fract; // x + const float x1 = x2*x2; // x^2 + const float x0 = x1*x2; // x^3 + float y0, y1, y2, y3; + + assert(fract < 1.0); + + y0 = _coeffs[0] * x0 + _coeffs[1] * x1 + _coeffs[2] * x2 + _coeffs[3] * x3; + y1 = _coeffs[4] * x0 + _coeffs[5] * x1 + _coeffs[6] * x2 + _coeffs[7] * x3; + y2 = _coeffs[8] * x0 + _coeffs[9] * x1 + _coeffs[10] * x2 + _coeffs[11] * x3; + y3 = _coeffs[12] * x0 + _coeffs[13] * x1 + _coeffs[14] * x2 + _coeffs[15] * x3; + + for (int c = 0; c < numChannels; c ++) + { + float out; + out = y0 * psrc[c] + y1 * psrc[c + numChannels] + y2 * psrc[c + 2 * numChannels] + y3 * psrc[c + 3 * numChannels]; + pdest[0] = (SAMPLETYPE)out; + pdest ++; + } + i ++; + + // update position fraction + fract += rate; + // update whole positions + int whole = (int)fract; + fract -= whole; + psrc += numChannels*whole; + srcCount += whole; + } + srcSamples = srcCount; + return i; +} |