diff options
Diffstat (limited to 'plugins/supereq/ffmpeg_fft/libavutil/rational.c')
-rw-r--r-- | plugins/supereq/ffmpeg_fft/libavutil/rational.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/plugins/supereq/ffmpeg_fft/libavutil/rational.c b/plugins/supereq/ffmpeg_fft/libavutil/rational.c new file mode 100644 index 00000000..3e8b885d --- /dev/null +++ b/plugins/supereq/ffmpeg_fft/libavutil/rational.c @@ -0,0 +1,131 @@ +/* + * rational numbers + * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> + * + * 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 + */ + +/** + * @file + * rational numbers + * @author Michael Niedermayer <michaelni@gmx.at> + */ + +#include <assert.h> +//#include <math.h> +#include <limits.h> + +#include "common.h" +#include "mathematics.h" +#include "rational.h" + +int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max){ + AVRational a0={0,1}, a1={1,0}; + int sign= (num<0) ^ (den<0); + int64_t gcd= av_gcd(FFABS(num), FFABS(den)); + + if(gcd){ + num = FFABS(num)/gcd; + den = FFABS(den)/gcd; + } + if(num<=max && den<=max){ + a1= (AVRational){num, den}; + den=0; + } + + while(den){ + uint64_t x = num / den; + int64_t next_den= num - den*x; + int64_t a2n= x*a1.num + a0.num; + int64_t a2d= x*a1.den + a0.den; + + if(a2n > max || a2d > max){ + if(a1.num) x= (max - a0.num) / a1.num; + if(a1.den) x= FFMIN(x, (max - a0.den) / a1.den); + + if (den*(2*x*a1.den + a0.den) > num*a1.den) + a1 = (AVRational){x*a1.num + a0.num, x*a1.den + a0.den}; + break; + } + + a0= a1; + a1= (AVRational){a2n, a2d}; + num= den; + den= next_den; + } + assert(av_gcd(a1.num, a1.den) <= 1U); + + *dst_num = sign ? -a1.num : a1.num; + *dst_den = a1.den; + + return den==0; +} + +AVRational av_mul_q(AVRational b, AVRational c){ + av_reduce(&b.num, &b.den, b.num * (int64_t)c.num, b.den * (int64_t)c.den, INT_MAX); + return b; +} + +AVRational av_div_q(AVRational b, AVRational c){ + return av_mul_q(b, (AVRational){c.den, c.num}); +} + +AVRational av_add_q(AVRational b, AVRational c){ + av_reduce(&b.num, &b.den, b.num * (int64_t)c.den + c.num * (int64_t)b.den, b.den * (int64_t)c.den, INT_MAX); + return b; +} + +AVRational av_sub_q(AVRational b, AVRational c){ + return av_add_q(b, (AVRational){-c.num, c.den}); +} + +AVRational av_d2q(double d, int max){ + AVRational a; +#define LOG2 0.69314718055994530941723212145817656807550013436025 + int exponent= FFMAX( (int)(log(fabs(d) + 1e-20)/LOG2), 0); + int64_t den= 1LL << (61 - exponent); + if (isnan(d)) + return (AVRational){0,0}; + av_reduce(&a.num, &a.den, (int64_t)(d * den + 0.5), den, max); + + return a; +} + +int av_nearer_q(AVRational q, AVRational q1, AVRational q2) +{ + /* n/d is q, a/b is the median between q1 and q2 */ + int64_t a = q1.num * (int64_t)q2.den + q2.num * (int64_t)q1.den; + int64_t b = 2 * (int64_t)q1.den * q2.den; + + /* rnd_up(a*d/b) > n => a*d/b > n */ + int64_t x_up = av_rescale_rnd(a, q.den, b, AV_ROUND_UP); + + /* rnd_down(a*d/b) < n => a*d/b < n */ + int64_t x_down = av_rescale_rnd(a, q.den, b, AV_ROUND_DOWN); + + return ((x_up > q.num) - (x_down < q.num)) * av_cmp_q(q2, q1); +} + +int av_find_nearest_q_idx(AVRational q, const AVRational* q_list) +{ + int i, nearest_q_idx = 0; + for(i=0; q_list[i].den; i++) + if (av_nearer_q(q, q_list[i], q_list[nearest_q_idx]) > 0) + nearest_q_idx = i; + + return nearest_q_idx; +} |