3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #ifndef AVUTIL_RATIONAL_H
29 #define AVUTIL_RATIONAL_H
33 #include "attributes.h"
36 * rational number numerator/denominator
38 typedef struct AVRational{
39 int num; ///< numerator
40 int den; ///< denominator
44 * Compare two rationals.
45 * @param a first rational
46 * @param b second rational
47 * @return 0 if a==b, 1 if a>b and -1 if a<b
49 static inline int av_cmp_q(AVRational a, AVRational b){
50 const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den;
52 if(tmp) return ((tmp ^ a.den ^ b.den)>>63)|1;
53 else if(b.den && a.den) return 0;
54 else if(a.num && b.num) return (a.num>>31) - (b.num>>31);
59 * Convert rational to double.
60 * @param a rational to convert
63 static inline double av_q2d(AVRational a){
64 return a.num / (double) a.den;
69 * This is useful for framerate calculations.
70 * @param dst_num destination numerator
71 * @param dst_den destination denominator
72 * @param num source numerator
73 * @param den source denominator
74 * @param max the maximum allowed for dst_num & dst_den
75 * @return 1 if exact, 0 otherwise
77 int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max);
80 * Multiply two rationals.
81 * @param b first rational
82 * @param c second rational
85 AVRational av_mul_q(AVRational b, AVRational c) av_const;
88 * Divide one rational by another.
89 * @param b first rational
90 * @param c second rational
93 AVRational av_div_q(AVRational b, AVRational c) av_const;
97 * @param b first rational
98 * @param c second rational
101 AVRational av_add_q(AVRational b, AVRational c) av_const;
104 * Subtract one rational from another.
105 * @param b first rational
106 * @param c second rational
109 AVRational av_sub_q(AVRational b, AVRational c) av_const;
112 * Convert a double precision floating point number to a rational.
113 * inf is expressed as {1,0} or {-1,0} depending on the sign.
115 * @param d double to convert
116 * @param max the maximum allowed numerator and denominator
117 * @return (AVRational) d
119 AVRational av_d2q(double d, int max) av_const;
122 * @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer
123 * than q1, 0 if they have the same distance.
125 int av_nearer_q(AVRational q, AVRational q1, AVRational q2);
128 * Find the nearest value in q_list to q.
129 * @param q_list an array of rationals terminated by {0, 0}
130 * @return the index of the nearest value found in the array
132 int av_find_nearest_q_idx(AVRational q, const AVRational* q_list);
134 #endif /* AVUTIL_RATIONAL_H */