X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Frational.c;h=405393619440283bf5ec71468be1b91016ecd5f3;hb=c98f3169bfb578c1a4e407b44524f0bfa3b4dc0c;hp=ac0c9d371452c241ffffd3c3bb622495fceb196b;hpb=0b0065992eb6652330f2c84d31de181c2d8956e6;p=ffmpeg diff --git a/libavutil/rational.c b/libavutil/rational.c index ac0c9d37145..40539361944 100644 --- a/libavutil/rational.c +++ b/libavutil/rational.c @@ -1,104 +1,145 @@ /* - * Rational numbers + * rational numbers * Copyright (c) 2003 Michael Niedermayer * - * This file is part of FFmpeg. + * This file is part of Libav. * - * FFmpeg is free software; you can redistribute it and/or + * Libav 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, + * Libav 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 + * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * */ /** - * @file rational.c - * Rational numbers + * @file + * rational numbers * @author Michael Niedermayer */ -//#include +#include "avassert.h" #include #include "common.h" #include "mathematics.h" #include "rational.h" -int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max){ - AVRational a0={0,1}, a1={1,0}; - int sign= (nom<0) ^ (den<0); - int64_t gcd= ff_gcd(FFABS(nom), FFABS(den)); +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){ - nom = FFABS(nom)/gcd; - den = FFABS(den)/gcd; + if (gcd) { + num = FFABS(num) / gcd; + den = FFABS(den) / gcd; } - if(nom<=max && den<=max){ - a1= (AVRational){nom, den}; - den=0; + if (num <= max && den <= max) { + a1 = (AVRational) { num, den }; + den = 0; } - while(den){ - uint64_t x = nom / den; - int64_t next_den= nom - den*x; - int64_t a2n= x*a1.num + a0.num; - int64_t a2d= x*a1.den + a0.den; + 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 (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) > nom*a1.den) - a1 = (AVRational){x*a1.num + a0.num, x*a1.den + a0.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}; - nom= den; - den= next_den; + a0 = a1; + a1 = (AVRational) { a2n, a2d }; + num = den; + den = next_den; } - assert(ff_gcd(a1.num, a1.den) <= 1U); + av_assert2(av_gcd(a1.num, a1.den) <= 1U); - *dst_nom = sign ? -a1.num : a1.num; + *dst_num = sign ? -a1.num : a1.num; *dst_den = a1.den; - return den==0; + 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); +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_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); +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_sub_q(AVRational b, AVRational c) +{ + return av_add_q(b, (AVRational) { -c.num, c.den }); } -AVRational av_d2q(double d, int max){ +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); + int exponent; + int64_t den; + if (isnan(d)) + return (AVRational) { 0,0 }; + if (isinf(d)) + return (AVRational) { d < 0 ? -1 : 1, 0 }; + exponent = FFMAX( (int)(log(fabs(d) + 1e-20)/LOG2), 0); + den = 1LL << (61 - exponent); 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; +}