fftlib.h

/* fftlib.h: Copyright (C) 2005 Istvan Varga This file is part of Csound. The Csound 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. Csound 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 Csound; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef CSOUND_FFTLIB_H #define CSOUND_FFTLIB_H #if !defined(__BUILDING_LIBCSOUND) # error "Csound plugins and host applications should not include fftlib.h" #endif #ifdef __cplusplus extern "C" { #endif /** * Returns the amplitude scale that should be applied to the result of * an inverse complex FFT with a length of 'FFTsize' samples. */ MYFLT csoundGetInverseComplexFFTScale(CSOUND *csound, int FFTsize); /** * Returns the amplitude scale that should be applied to the result of * an inverse real FFT with a length of 'FFTsize' samples. */ MYFLT csoundGetInverseRealFFTScale(CSOUND *csound, int FFTsize); /** * Compute in-place complex FFT * FFTsize: FFT length in samples * buf: array of FFTsize*2 MYFLT values, * in interleaved real/imaginary format */ void csoundComplexFFT(CSOUND *csound, MYFLT *buf, int FFTsize); /** * Compute in-place inverse complex FFT * FFTsize: FFT length in samples * buf: array of FFTsize*2 MYFLT values, * in interleaved real/imaginary format * Output should be scaled by the return value of * csoundGetInverseComplexFFTScale(csound, FFTsize). */ void csoundInverseComplexFFT(CSOUND *csound, MYFLT *buf, int FFTsize); /** * Compute in-place real FFT * FFTsize: FFT length in samples * buf: array of FFTsize MYFLT values; output is in interleaved * real/imaginary format, except for buf[1] which is the real * part for the Nyquist frequency */ void csoundRealFFT(CSOUND *csound, MYFLT *buf, int FFTsize); /** * Compute in-place inverse real FFT * FFTsize: FFT length in samples * buf: array of FFTsize MYFLT values; input is expected to be in * interleaved real/imaginary format, except for buf[1] which * is the real part for the Nyquist frequency * Output should be scaled by the return value of * csoundGetInverseRealFFTScale(csound, FFTsize). */ void csoundInverseRealFFT(CSOUND *csound, MYFLT *buf, int FFTsize); /** * Multiply two arrays (buf1 and buf2) of complex data in the format * returned by csoundRealFFT(), and leave the result in outbuf, which * may be the same as either buf1 or buf2. * An amplitude scale of 'scaleFac' is also applied. * The arrays should contain 'FFTsize' MYFLT values. */ void csoundRealFFTMult(CSOUND *csound, MYFLT *outbuf, MYFLT *buf1, MYFLT *buf2, int FFTsize, MYFLT scaleFac); /** * Compute in-place real FFT, allowing non power of two FFT sizes. * * buf: array of FFTsize + 2 MYFLT values; output is in interleaved * real/imaginary format (note: the real part of the Nyquist * frequency is stored in buf[FFTsize], and not in buf[1]). * FFTsize: FFT length in samples; not required to be an integer power of two, * but should be even and not have too many factors. */ void csoundRealFFTnp2(CSOUND *csound, MYFLT *buf, int FFTsize); /** * Compute in-place inverse real FFT, allowing non power of two FFT sizes. * The output does not need to be scaled. * * buf: array of FFTsize + 2 MYFLT values, in interleaved real/imaginary * format (note: the real part of the Nyquist frequency is stored * in buf[FFTsize], and not in buf[1]). * FFTsize: FFT length in samples; not required to be an integer power of two, * but should be even and not have too many factors. */ void csoundInverseRealFFTnp2(CSOUND *csound, MYFLT *buf, int FFTsize); #ifdef __cplusplus } #endif #endif /* CSOUND_FFTLIB_H */

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