2 * Copyright (c) 2015 Paul B Mahol
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifndef AVFILTER_WINDOW_FUNC_H
23 #define AVFILTER_WINDOW_FUNC_H
26 #include "libavutil/avassert.h"
28 enum WindowFunc { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN,
29 WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP,
30 WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL,
31 WFUNC_BHANN, WFUNC_LANCZOS, WFUNC_GAUSS, WFUNC_TUKEY,
32 WFUNC_DOLPH, WFUNC_CAUCHY, WFUNC_PARZEN, WFUNC_POISSON,
35 static inline void generate_window_func(float *lut, int N, int win_func,
42 for (n = 0; n < N; n++)
47 for (n = 0; n < N; n++)
48 lut[n] = 1.-fabs((n-(N-1)/2.)/((N-1)/2.));
52 for (n = 0; n < N; n++)
53 lut[n] = .5*(1-cos(2*M_PI*n/(N-1)));
57 for (n = 0; n < N; n++)
58 lut[n] = .54-.46*cos(2*M_PI*n/(N-1));
62 for (n = 0; n < N; n++)
63 lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1));
67 for (n = 0; n < N; n++)
68 lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.);
72 for (n = 0; n < N; n++)
73 lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))-
74 1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))-
75 0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))-
76 0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))-
77 0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1));
81 for (n = 0; n < N; n++)
82 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));
86 for (n = 0; n < N; n++)
87 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));
91 for (n = 0; n < N; n++)
92 lut[n] = 0.62-0.48*fabs(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1));
96 for (n = 0; n < N; n++)
97 lut[n] = sin(M_PI*n/(N-1));
101 for (n = 0; n < N; n++)
102 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));
106 #define SINC(x) (!(x)) ? 1 : sin(M_PI * (x))/(M_PI * (x));
107 for (n = 0; n < N; n++)
108 lut[n] = SINC((2.*n)/(N-1)-1);
112 #define SQR(x) ((x)*(x))
113 for (n = 0; n < N; n++)
114 lut[n] = exp(-0.5 * SQR((n-(N-1)/2)/(0.4*(N-1)/2.f)));
118 for (n = 0; n < N; n++) {
121 if (FFABS(n - M) >= 0.3 * M) {
122 lut[n] = 0.5 * (1 + cos((M_PI*(FFABS(n - M) - 0.3 * M))/((1 - 0.3) * M)));
130 double b = cosh(7.6009022095419887 / (N-1)), sum, t, c, norm = 0;
132 for (c = 1 - 1 / (b*b), n = (N-1) / 2; n >= 0; --n) {
133 for (sum = !n, b = t = j = 1; j <= n && sum != t; b *= (n-j) * (1./j), ++j)
134 t = sum, sum += (b *= c * (N - n - j) * (1./j));
135 sum /= (N - 1 - n), sum /= (norm = norm ? norm : sum);
137 lut[N - 1 - n] = sum;
142 for (n = 0; n < N; n++) {
143 double x = 2 * ((n / (double)(N - 1)) - .5);
145 if (x <= -.5 || x >= .5) {
148 lut[n] = FFMIN(1, fabs(1/(1+4*16*x*x)));
154 for (n = 0; n < N; n++) {
155 double x = 2 * ((n / (double)(N - 1)) - .5);
157 if (x > 0.25 && x <= 0.5) {
158 lut[n] = -2 * powf(-1 + 2 * x, 3);
159 } else if (x >= -.5 && x < -.25) {
160 lut[n] = 2 * powf(1 + 2 * x, 3);
161 } else if (x >= -.25 && x < 0) {
162 lut[n] = 1 - 24 * x * x - 48 * x * x * x;
163 } else if (x >= 0 && x <= .25) {
164 lut[n] = 1 - 24 * x * x + 48 * x * x * x;
172 for (n = 0; n < N; n++) {
173 double x = 2 * ((n / (double)(N - 1)) - .5);
175 if (x >= 0 && x <= .5) {
177 } else if (x < 0 && x >= -.5) {
190 #endif /* AVFILTER_WINDOW_FUNC_H */