mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
b15a2f2504
Possible since 9325d88eba.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
36 lines
1.2 KiB
C
36 lines
1.2 KiB
C
/*
|
|
* Copyright (c) 2011 Justin Ruggles
|
|
*
|
|
* 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
|
|
*/
|
|
|
|
#include "libavutil/common.h"
|
|
#include "libavutil/mathematics.h"
|
|
#include "adx.h"
|
|
|
|
void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff)
|
|
{
|
|
double a, b, c;
|
|
|
|
a = M_SQRT2 - cos(2.0 * M_PI * cutoff / sample_rate);
|
|
b = M_SQRT2 - 1.0;
|
|
c = (a - sqrt((a + b) * (a - b))) / b;
|
|
|
|
coeff[0] = lrintf(c * 2.0 * (1 << bits));
|
|
coeff[1] = lrintf(-(c * c) * (1 << bits));
|
|
}
|