| /* |
| * Copyright (c) 2015 Paul B Mahol |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg 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. |
| * |
| * FFmpeg 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 FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| |
| #ifndef AVFILTER_WINDOW_FUNC_H |
| #define AVFILTER_WINDOW_FUNC_H |
| |
| #include <math.h> |
| #include "libavutil/avassert.h" |
| |
| enum WindowFunc { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN, |
| WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP, |
| WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL, |
| WFUNC_BHANN, WFUNC_LANCZOS, WFUNC_GAUSS, WFUNC_TUKEY, |
| WFUNC_DOLPH, WFUNC_CAUCHY, WFUNC_PARZEN, WFUNC_POISSON, |
| NB_WFUNC }; |
| |
| static inline void generate_window_func(float *lut, int N, int win_func, |
| float *overlap) |
| { |
| int n; |
| |
| switch (win_func) { |
| case WFUNC_RECT: |
| for (n = 0; n < N; n++) |
| lut[n] = 1.; |
| *overlap = 0.; |
| break; |
| case WFUNC_BARTLETT: |
| for (n = 0; n < N; n++) |
| lut[n] = 1.-fabs((n-(N-1)/2.)/((N-1)/2.)); |
| *overlap = 0.5; |
| break; |
| case WFUNC_HANNING: |
| for (n = 0; n < N; n++) |
| lut[n] = .5*(1-cos(2*M_PI*n/(N-1))); |
| *overlap = 0.5; |
| break; |
| case WFUNC_HAMMING: |
| for (n = 0; n < N; n++) |
| lut[n] = .54-.46*cos(2*M_PI*n/(N-1)); |
| *overlap = 0.5; |
| break; |
| case WFUNC_BLACKMAN: |
| for (n = 0; n < N; n++) |
| lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1)); |
| *overlap = 0.661; |
| break; |
| case WFUNC_WELCH: |
| for (n = 0; n < N; n++) |
| lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.); |
| *overlap = 0.293; |
| break; |
| case WFUNC_FLATTOP: |
| for (n = 0; n < N; n++) |
| lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))- |
| 1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))- |
| 0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))- |
| 0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))- |
| 0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1)); |
| *overlap = 0.841; |
| break; |
| case WFUNC_BHARRIS: |
| for (n = 0; n < N; n++) |
| 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)); |
| *overlap = 0.661; |
| break; |
| case WFUNC_BNUTTALL: |
| for (n = 0; n < N; n++) |
| 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)); |
| *overlap = 0.661; |
| break; |
| case WFUNC_BHANN: |
| for (n = 0; n < N; n++) |
| lut[n] = 0.62-0.48*fabs(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1)); |
| *overlap = 0.5; |
| break; |
| case WFUNC_SINE: |
| for (n = 0; n < N; n++) |
| lut[n] = sin(M_PI*n/(N-1)); |
| *overlap = 0.75; |
| break; |
| case WFUNC_NUTTALL: |
| for (n = 0; n < N; n++) |
| 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)); |
| *overlap = 0.663; |
| break; |
| case WFUNC_LANCZOS: |
| #define SINC(x) (!(x)) ? 1 : sin(M_PI * (x))/(M_PI * (x)); |
| for (n = 0; n < N; n++) |
| lut[n] = SINC((2.*n)/(N-1)-1); |
| *overlap = 0.75; |
| break; |
| case WFUNC_GAUSS: |
| #define SQR(x) ((x)*(x)) |
| for (n = 0; n < N; n++) |
| lut[n] = exp(-0.5 * SQR((n-(N-1)/2)/(0.4*(N-1)/2.f))); |
| *overlap = 0.75; |
| break; |
| case WFUNC_TUKEY: |
| for (n = 0; n < N; n++) { |
| float M = (N-1)/2.; |
| |
| if (FFABS(n - M) >= 0.3 * M) { |
| lut[n] = 0.5 * (1 + cos((M_PI*(FFABS(n - M) - 0.3 * M))/((1 - 0.3) * M))); |
| } else { |
| lut[n] = 1; |
| } |
| } |
| *overlap = 0.33; |
| break; |
| case WFUNC_DOLPH: { |
| double b = cosh(7.6009022095419887 / (N-1)), sum, t, c, norm = 0; |
| int j; |
| for (c = 1 - 1 / (b*b), n = (N-1) / 2; n >= 0; --n) { |
| for (sum = !n, b = t = j = 1; j <= n && sum != t; b *= (n-j) * (1./j), ++j) |
| t = sum, sum += (b *= c * (N - n - j) * (1./j)); |
| sum /= (N - 1 - n), sum /= (norm = norm ? norm : sum); |
| lut[n] = sum; |
| lut[N - 1 - n] = sum; |
| } |
| *overlap = 0.5;} |
| break; |
| case WFUNC_CAUCHY: |
| for (n = 0; n < N; n++) { |
| double x = 2 * ((n / (double)(N - 1)) - .5); |
| |
| if (x <= -.5 || x >= .5) { |
| lut[n] = 0; |
| } else { |
| lut[n] = FFMIN(1, fabs(1/(1+4*16*x*x))); |
| } |
| } |
| *overlap = 0.75; |
| break; |
| case WFUNC_PARZEN: |
| for (n = 0; n < N; n++) { |
| double x = 2 * ((n / (double)(N - 1)) - .5); |
| |
| if (x > 0.25 && x <= 0.5) { |
| lut[n] = -2 * powf(-1 + 2 * x, 3); |
| } else if (x >= -.5 && x < -.25) { |
| lut[n] = 2 * powf(1 + 2 * x, 3); |
| } else if (x >= -.25 && x < 0) { |
| lut[n] = 1 - 24 * x * x - 48 * x * x * x; |
| } else if (x >= 0 && x <= .25) { |
| lut[n] = 1 - 24 * x * x + 48 * x * x * x; |
| } else { |
| lut[n] = 0; |
| } |
| } |
| *overlap = 0.75; |
| break; |
| case WFUNC_POISSON: |
| for (n = 0; n < N; n++) { |
| double x = 2 * ((n / (double)(N - 1)) - .5); |
| |
| if (x >= 0 && x <= .5) { |
| lut[n] = exp(-6*x); |
| } else if (x < 0 && x >= -.5) { |
| lut[n] = exp(6*x); |
| } else { |
| lut[n] = 0; |
| } |
| } |
| *overlap = 0.75; |
| break; |
| default: |
| av_assert0(0); |
| } |
| } |
| |
| #endif /* AVFILTER_WINDOW_FUNC_H */ |
