| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * Copyright (c) 2011 Justin Ruggles | ||
| 3 | * | ||
| 4 | * This file is part of FFmpeg. | ||
| 5 | * | ||
| 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. | ||
| 10 | * | ||
| 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. | ||
| 15 | * | ||
| 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 | ||
| 19 | */ | ||
| 20 | |||
| 21 | #include "libavutil/common.h" | ||
| 22 | #include "libavutil/mathematics.h" | ||
| 23 | #include "adx.h" | ||
| 24 | |||
| 25 | 5 | void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff) | |
| 26 | { | ||
| 27 | double a, b, c; | ||
| 28 | |||
| 29 | 5 | a = M_SQRT2 - cos(2.0 * M_PI * cutoff / sample_rate); | |
| 30 | 5 | b = M_SQRT2 - 1.0; | |
| 31 | 5 | c = (a - sqrt((a + b) * (a - b))) / b; | |
| 32 | |||
| 33 | 5 | coeff[0] = lrintf(c * 2.0 * (1 << bits)); | |
| 34 | 5 | coeff[1] = lrintf(-(c * c) * (1 << bits)); | |
| 35 | 5 | } | |
| 36 |