mirror of
https://github.com/FFmpeg/FFmpeg.git
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200 lines
6.7 KiB
C
200 lines
6.7 KiB
C
/*
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* Copyright (c) 2015 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVFILTER_WINDOW_FUNC_H
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#define AVFILTER_WINDOW_FUNC_H
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#include <math.h>
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#include "libavutil/avassert.h"
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enum WindowFunc { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN,
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WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP,
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WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL,
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WFUNC_BHANN, WFUNC_LANCZOS, WFUNC_GAUSS, WFUNC_TUKEY,
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WFUNC_DOLPH, WFUNC_CAUCHY, WFUNC_PARZEN, WFUNC_POISSON,
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WFUNC_BOHMAN,
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NB_WFUNC };
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static inline void generate_window_func(float *lut, int N, int win_func,
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float *overlap)
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{
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int n;
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switch (win_func) {
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case WFUNC_RECT:
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for (n = 0; n < N; n++)
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lut[n] = 1.;
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*overlap = 0.;
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break;
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case WFUNC_BARTLETT:
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for (n = 0; n < N; n++)
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lut[n] = 1.-fabs((n-(N-1)/2.)/((N-1)/2.));
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*overlap = 0.5;
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break;
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case WFUNC_HANNING:
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for (n = 0; n < N; n++)
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lut[n] = .5*(1-cos(2*M_PI*n/(N-1)));
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*overlap = 0.5;
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break;
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case WFUNC_HAMMING:
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for (n = 0; n < N; n++)
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lut[n] = .54-.46*cos(2*M_PI*n/(N-1));
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*overlap = 0.5;
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break;
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case WFUNC_BLACKMAN:
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for (n = 0; n < N; n++)
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lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1));
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*overlap = 0.661;
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break;
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case WFUNC_WELCH:
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for (n = 0; n < N; n++)
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lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.);
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*overlap = 0.293;
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break;
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case WFUNC_FLATTOP:
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for (n = 0; n < N; n++)
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lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))-
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1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))-
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0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))-
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0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))-
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0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1));
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*overlap = 0.841;
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break;
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case WFUNC_BHARRIS:
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for (n = 0; n < N; n++)
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lut[n] = 0.35875-0.48829*cos(2*M_PI*n/(N-1))+0.14128*cos(4*M_PI*n/(N-1))-0.01168*cos(6*M_PI*n/(N-1));
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*overlap = 0.661;
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break;
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case WFUNC_BNUTTALL:
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for (n = 0; n < N; n++)
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lut[n] = 0.3635819-0.4891775*cos(2*M_PI*n/(N-1))+0.1365995*cos(4*M_PI*n/(N-1))-0.0106411*cos(6*M_PI*n/(N-1));
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*overlap = 0.661;
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break;
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case WFUNC_BHANN:
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for (n = 0; n < N; n++)
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lut[n] = 0.62-0.48*fabs(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1));
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*overlap = 0.5;
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break;
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case WFUNC_SINE:
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for (n = 0; n < N; n++)
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lut[n] = sin(M_PI*n/(N-1));
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*overlap = 0.75;
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break;
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case WFUNC_NUTTALL:
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for (n = 0; n < N; n++)
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lut[n] = 0.355768-0.487396*cos(2*M_PI*n/(N-1))+0.144232*cos(4*M_PI*n/(N-1))-0.012604*cos(6*M_PI*n/(N-1));
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*overlap = 0.663;
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break;
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case WFUNC_LANCZOS:
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#define SINC(x) (!(x)) ? 1 : sin(M_PI * (x))/(M_PI * (x));
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for (n = 0; n < N; n++)
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lut[n] = SINC((2.*n)/(N-1)-1);
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*overlap = 0.75;
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break;
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case WFUNC_GAUSS:
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#define SQR(x) ((x)*(x))
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for (n = 0; n < N; n++)
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lut[n] = exp(-0.5 * SQR((n-(N-1)/2)/(0.4*(N-1)/2.f)));
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*overlap = 0.75;
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break;
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case WFUNC_TUKEY:
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for (n = 0; n < N; n++) {
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float M = (N-1)/2.;
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if (FFABS(n - M) >= 0.3 * M) {
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lut[n] = 0.5 * (1 + cos((M_PI*(FFABS(n - M) - 0.3 * M))/((1 - 0.3) * M)));
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} else {
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lut[n] = 1;
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}
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}
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*overlap = 0.33;
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break;
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case WFUNC_DOLPH: {
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double b = cosh(7.6009022095419887 / (N-1)), sum, t, c, norm = 0;
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int j;
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for (c = 1 - 1 / (b*b), n = (N-1) / 2; n >= 0; --n) {
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for (sum = !n, b = t = j = 1; j <= n && sum != t; b *= (n-j) * (1./j), ++j)
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t = sum, sum += (b *= c * (N - n - j) * (1./j));
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sum /= (N - 1 - n), sum /= (norm = norm ? norm : sum);
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lut[n] = sum;
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lut[N - 1 - n] = sum;
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}
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*overlap = 0.5;}
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break;
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case WFUNC_CAUCHY:
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for (n = 0; n < N; n++) {
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double x = 2 * ((n / (double)(N - 1)) - .5);
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if (x <= -.5 || x >= .5) {
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lut[n] = 0;
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} else {
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lut[n] = FFMIN(1, fabs(1/(1+4*16*x*x)));
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}
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}
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*overlap = 0.75;
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break;
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case WFUNC_PARZEN:
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for (n = 0; n < N; n++) {
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double x = 2 * ((n / (double)(N - 1)) - .5);
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if (x > 0.25 && x <= 0.5) {
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lut[n] = -2 * powf(-1 + 2 * x, 3);
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} else if (x >= -.5 && x < -.25) {
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lut[n] = 2 * powf(1 + 2 * x, 3);
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} else if (x >= -.25 && x < 0) {
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lut[n] = 1 - 24 * x * x - 48 * x * x * x;
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} else if (x >= 0 && x <= .25) {
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lut[n] = 1 - 24 * x * x + 48 * x * x * x;
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} else {
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lut[n] = 0;
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}
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}
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*overlap = 0.75;
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break;
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case WFUNC_POISSON:
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for (n = 0; n < N; n++) {
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double x = 2 * ((n / (double)(N - 1)) - .5);
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if (x >= 0 && x <= .5) {
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lut[n] = exp(-6*x);
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} else if (x < 0 && x >= -.5) {
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lut[n] = exp(6*x);
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} else {
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lut[n] = 0;
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}
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}
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*overlap = 0.75;
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break;
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case WFUNC_BOHMAN:
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for (n = 0; n < N; n++) {
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double x = 2 * ((n / (double)(N - 1))) - 1.;
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lut[n] = (1 - fabs(x)) * cos(M_PI*fabs(x)) + 1./M_PI*sin(M_PI*fabs(x));
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}
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*overlap = 0.75;
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break;
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default:
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av_assert0(0);
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}
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}
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#endif /* AVFILTER_WINDOW_FUNC_H */
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