LCOV - code coverage report
Current view: top level - libavcodec - kbdwin.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 20 20 100.0 %
Date: 2017-12-17 16:07:53 Functions: 2 2 100.0 %

          Line data    Source code
       1             : /*
       2             :  * This file is part of FFmpeg.
       3             :  *
       4             :  * FFmpeg is free software; you can redistribute it and/or
       5             :  * modify it under the terms of the GNU Lesser General Public
       6             :  * License as published by the Free Software Foundation; either
       7             :  * version 2.1 of the License, or (at your option) any later version.
       8             :  *
       9             :  * FFmpeg is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             :  * Lesser General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU Lesser General Public
      15             :  * License along with FFmpeg; if not, write to the Free Software
      16             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      17             :  */
      18             : 
      19             : #include "libavutil/avassert.h"
      20             : #include "libavutil/mathematics.h"
      21             : #include "libavutil/attributes.h"
      22             : #include "kbdwin.h"
      23             : 
      24             : #define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation
      25             : 
      26         676 : av_cold void ff_kbd_window_init(float *window, float alpha, int n)
      27             : {
      28             :    int i, j;
      29         676 :    double sum = 0.0, bessel, tmp;
      30             :    double local_window[FF_KBD_WINDOW_MAX];
      31         676 :    double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n);
      32             : 
      33         676 :    av_assert0(n <= FF_KBD_WINDOW_MAX);
      34             : 
      35      365604 :    for (i = 0; i < n; i++) {
      36      364928 :        tmp = i * (n - i) * alpha2;
      37      364928 :        bessel = 1.0;
      38    18611328 :        for (j = BESSEL_I0_ITER; j > 0; j--)
      39    18246400 :            bessel = bessel * tmp / (j * j) + 1;
      40      364928 :        sum += bessel;
      41      364928 :        local_window[i] = sum;
      42             :    }
      43             : 
      44         676 :    sum++;
      45      365604 :    for (i = 0; i < n; i++)
      46      364928 :        window[i] = sqrt(local_window[i] / sum);
      47         676 : }
      48             : 
      49          36 : av_cold void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n)
      50             : {
      51             :     int i;
      52             :     float local_window[FF_KBD_WINDOW_MAX];
      53             : 
      54          36 :     ff_kbd_window_init(local_window, alpha, n);
      55       19492 :     for (i = 0; i < n; i++)
      56       19456 :         window[i] = (int)floor(2147483647.0 * local_window[i] + 0.5);
      57          36 : }

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